WO2008070739A1 - Ksp activators - Google Patents

Abstract

The present invention provides compounds that modulate kinesin activity. The present invention provides methods for discovering compounds that modulate kinesin activity. The present invention also provides methods and compositions for treatment of disorders mediated by abnormal cellular proliferation activities.

Description

KSP ACTIVATORS

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/868,908, filed December 6, 2006, which is incorporated by reference herein in its entirety.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT [0002] NOT APPLICABLE

REFERENCE TO A "SEQUENCE LISTING," A TABLE, OR A COMPUTER

PROGRAM LISTING APPENDDC SUBMITTED ON A COMPACT DISK. [0003] NOT APPLICABLE

BACKGROUND OF THE INVENTION

[0004] The kinesin superfamily is comprised of proteins which utilize a conserved catalytic motor domain to generate intracellular movement of vesicles or macromolecules along microtubules in diverse eukaryotic cellular processes (e.g., cell proliferation). Over 90 kinesin proteins can be classified into at least 8 subfamilies based on primary amino acid sequence, domain structure, velocity of movement, and cellular function. The motor domain is a compact structure of approximately 340 amino acids, and can be located at the N- terminus, in the internal region, or at the C-terminus of the kinesin molecule. Most of the kinesin proteins have an N-terminal catalytic motor domain, e.g., the BimC and the KHC families (See, e.g., Goldstein et al., Annu. Rev. Cell Dev. Biol., 15:141-83,1999; Moore, J. D. and Endow, S. A., Bioassays 18:207-219, 1996). During mitosis, kinesins organize microtubules into the bipolar structure that is the mitotic spindle, and mediate movement of chromosomes along spindle microtubules, as well as structural changes in the mitotic spindle associated with specific phases of mitosis. These "molecular motors" translate energy released by hydrolysis of ATP into mechanical force, which drives the directional movement of cellular cargoes along microtubules. [0005] The prototypical native kinesin molecule is a heterotetramer comprised of two heavy polypeptide chains (KHCs) and two light polypeptide chains (KLCs). The KHC homodimer is typically referred to as "kinesin" and is classified as a member of the KHC kinesin family (Goldstein et al., Annu. Rev. Cell Dev. Biol., 15:141-83,1999). The human form of KHC has been cloned (Navone et al., J. Cell Biol, 117:1263-75 (1992)). Human KHC N-terminal fragments have reportedly been expressed in E. coli and purified (Fujiwara, et al., Biophys. J. 69:1563-8, 1995; Vale et al., Nature 380:451-3, 1996). The crystal structure of the KHC motor domain has been reported (KuIl et al., Nature 380:550-555, 1996). Motility activity of KHC has also been reported.

[0006] Another notable kinesin that has been identified is kinesin spindle protein ("KSP"), a member of the BimC kinesin family that is characterized by a conserved, globular motor domain at the amino terminus followed by a non-conserved, rod-like helical coiled-coil domain and a BimC box at the carboxyl terminus (Endow, Trends Biol. Sci. 16:221-225, 1991; Sanders et al., J. Cell Biol. 128:617-624, 1995). During mitosis, KSP associates with microtubules of the mitotic spindle. Microinjection of antibody directed against KSP into human cells prevents spindle pole separation during prometaphase, giving rise to monopolar spindles and causing mitotic arrest. KSP and related kinesins bundle antiparallel microtubules and slide them relative to one another, thus forcing the two spindle poles apart. KSP may also mediate in anaphase B spindle elongation and focusing of microtubules at the spindle pole. The current Ksp inhibitors in clinical development are molecules that, like monastrol (Maliga et al BMC Chem Biol 6:2, 2006), bind near the loop 5 region of KSP and are affected by mutations in this region of the protein. This can possibly make their efficacy in clinical settings susceptible to spontaneous mutations in the loop 5 region of KSP. The activator CKl 230969 is able to activate the mutant protein indicating that this mechanism of KSP modulation might be more resistant to mutations in the loop 5 region.

[0007] Human KSP (also termed HsEg5) has been cloned and characterized (see, e.g., Blangy et al, Cell, 83:1159-69 (1995); Galgio et al., J. Cell Biol., 135:399-414, 1996; Whitehead et al., J. Cell Sci., 111 :2551-2561, 1998; Kaiser, et al., J. Biol. Chem., 274:18925- 31, 1999; GenBank accession numbers: X85137, NM 004523). Drosophila (Heck et al., J. Cell Biol., 123:665-79, 1993) and Xenopus (Le Guellec et al., MoI. Cell Biol., 11:3395-8, 1991) homologs of KSP have been reported. Drosophila KLP61F/KRP130 has reportedly been purified in native form (Cole, et al., J. Biol. Chem., 269:22913-22916, 1994), expressed in E. coli,(Barton, et al., MoI. Biol. Cell, 6:1563-74, 1995) and reported to have motility and ATPase activities (Cole, et al., supra; Barton, et al., supra). Xenopus Eg5 was expressed in E. coli and reported to possess motility activity (Sawin, et al., Nature, 359:540-3, 1992; Lockhart and Cross, Biochemistry, 35:2365-73, 1996; Crevel, et al, J. MoI. Biol., 273:160- 170, 1997) and ATPase activity (Lockhart and Cross, supra; Crevel et al., supra).

[0008] Besides KSP, other members of the BimC family include BimC, CIN8, cut7, KJPl ,

KLP61F (Barton et al., MoI. Biol. Cell. 6:1563-1574, 1995; Cottingham & Hoyt, J. Cell Biol.

138:1041-1053, 1997; DeZwaan et al., J. Cell Biol. 138:1023-1040, 1997; Gaglio et al., J.

Cell Biol. 135:399-414, 1996; Geiser et al., MoI. Biol. Cell 8:1035-1050, 1997; Heck et al., J.

Cell Biol. 123:665-679, 1993; Hoyt et al., J. Cell Biol. 118:109-120, 1992; Hoyt et al., Genetics 135:35-44, 1993; Huyett et al., J. Cell Sci. 111 :295-301, 1998; Miller et al., MoI.

Biol. Cell 9:2051-2068, 1998; Roof et al., J. Cell Biol. 118:95-108, 1992; Sanders et al., J.

Cell Biol. 137:417-431,1997; Sanders et al., MoI. Biol. Cell 8:1025-0133, 1997; Sanders et al., J. Cell Biol. 128:617-624, 1995; Sanders & Hoyt, Cell 70:451-458, 1992; Sharp et al., J.

Cell Biol. 144:125-138, 1999; Straight et al., J. Cell Biol. 143:687-694, 1998; Whitehead & Rattner, J. Cell Sci. 111:2551-2561, 1998; Wilson et al., J. Cell Sci. 110:451-464, 1997).

[0009] The present invention surprisingly provides methods for activating kinesins.

BRIEF SUMMARY OF THE INVENTION

[0010] In a first embodiment, the present invention provides a method of activating a kinesin comprising the step of contacting the kinesin with a compound of Formula I:

R¹ is a member selected from the group consisting of halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₂-C₆ alkynyl, C₂-C₆ alkenyl, -N(R⁴,R⁵), cyano, -OR⁹, -SR⁹, a C₃-C₈ cycloalkyl substituted with 0-2 R⁶ groups, a C₆-C₁₂ aryl ring system substituted with 0-3 R⁷ groups, a heteroaryl ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R groups and a heterocyclic ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-5 R⁸ groups. L is a linker selected from the group consisting of a bond, Ci-C₆ alkyl and C₃-C₈ cycloalkyl. R² is a member selected from the group consisting of hydrogen and Ci-C₆ alkyl. Alternatively, R^]-L and R² combine to form a heterocyclic ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R⁸ groups. A is a 5-membered heteroaryl ring system having 2-3 heteroatoms each independently selected from the group consisting of N, O and S. Each R³ is independently a member selected from the group consisting of hydrogen, halogen, Ci-C₆ alkyl, Ci-C₆ alkoxy and C₃-C₈ cycloalkyl. Alternatively, two R³ groups combine to form a member selected from the group consisting of a phenyl ring and a C₅-C₈ cycloalkyl. Each of R⁴ and R⁵ is a member selected from the group consisting of hydrogen and Ci-C₆ alkyl. Each R⁶ is independently a member selected from the group consisting of hydrogen and Ci-C₆ alkyl. Alternatively, two R⁶ groups combine to form a phenyl group. Each R⁷ is independently selected from the group consisting of hydrogen, -N(R⁴,R⁵), halogen, -C]-C₆ alkoxy and Ci-C₆ alkyl. Each R⁸ is independently selected from the group consisting of hydrogen and Ci-C₆ alkyl. R⁹ is a member selected from the group consisting of hydrogen, Ci-C₆ alkyl and a -C_J-C₄ alkyl-C₆-Ci₂ aryl ring system. And salts, hydrates, isomers and prodrugs thereof. In this manner, the kinesin is activated.

[0011] hi a second embodiment, the present invention provides a method of treating a disease by activating a kinesin with a compound of Formula I.

[0012] hi a third embodiment, the present invention provides a method of modulating the ATPase activity of a domain of cellular proliferation protein KSP comprising the step of contacting KSP with a compound of Formula I.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1. Figure 1 shows one example of an enzyme coupled assay system that can be utilized to assay for the production of ADP by a target protein that directly or indirectly produces ADP. The assay can be utilized in screening methods to identify modulators of the target protein by conducting the assay, for example, in the presence and absence of a candidate agent. This particular system utilizes pyruvate kinase to regenerate ATP and couples the oxidation of pyruvate to the conversion of AMPLEX RED (Molecular Probes, Inc., Eugene Oregon) to Resorufin.

[0014] Figure 2. Figure 2 shows SK-OV-3 cells treated with compound 82. Figure 2A shows SK-OV-3 cells treated with compound 82 and stained for Tubulin. Figure 2B shows SK-OV-3 cells treated with DMSO and stained for Tubulin. [0015] Figure 3. Figure 3 shows SK-OV-3 cells treated with compound 82. Figure 3A shows SK-OV-3 cells treated with 20 μM compound 82 and stained with Hoechst. Figure 3B shows SK-OV-3 cells treated with 20 μM compound 82 and stained for Tubulin. Figure 3 C shows SK-OV-3 cells treated with DMSO and stained with Hoechst. Figure 3D shows SK- OV-3 cells treated with DMSO and stained for Tubulin.

[0016] Figure 4. Figure 4 shows that the basal ATPase activator compound 16 (CK1230969) is less sensitive to loop 5 mutation than monastrol.

DETAILED DESCRIPTION OF THE INVENTION I. Definitions

[0017] As used herein, the term "activating" refers to the process of increasing the activity of a biomolecule, such as an enzyme, protein, or cell, beyond its normal activity level.

[0018] As used herein, the term "alkenyl" refers to either a straight chain or branched alkenyl of 2 to 6 carbon atoms, such as vinyl, propenyl, isopropenyl, butenyl, isobutenyl, butadienyl, pentenyl or hexadienyl. Alkenyl groups of the present invention can also be substituted with groups such as halogen and cyano.

[0019] As used herein, the term "alkyl" refers to a straight or branched chain, saturated, aliphatic radical having the number of carbon atoms indicated. For example, C₁-C₆ alkyl includes methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, tertbutyl, etc. Alkyl groups of the present invention can also be substituted with groups such as halogen and cyano.

[0020] As used herein, the term "alkynyl" refers to either a straight chain or branched alkyl of 2 to 6 carbon atoms having an alkynyl group therein, such as acetylenyl, propynyl or butynyl. Alkynyl groups of the present invention can also be substituted with groups such as halogen and cyano.

[0021] As used herein, the term "aryl" refers to a monocyclic or fused bicyclic, tricyclic or greater, aromatic ring assembly containing 6 to 16 ring carbon atoms. For example, aryl may be phenyl or naphthyl, preferably phenyl. "Arylene" means a divalent radical derived from an aryl group. Aryl groups can be mono-, di- or tri-substituted by one, two or three radicals selected from alkyl, alkoxy, hydroxy, halogen, cyano, amino, amino-alkyl, trifluoromethyl, haloalkyl, amido, esters, carboxylic acid, alkylenedioxy and oxy-C₂-C₃-alkylene; all of which are optionally further substituted, for instance as hereinbefore defined; or 1- or 2-naphthyl; or 1- or 2-phenanthrenyl. Alkylenedioxy is a divalent substitute attached to two adjacent carbon atoms of phenyl, e.g. methylenedioxy or ethylenedioxy. Oxy-C₂-C₃-alkylene is also a divalent substituent attached to two adjacent carbon atoms of phenyl, e.g. oxyethylene or oxypropylene. An example for oxy- C₂-C₃-alkylene-phenyl is 2,3-dihydrobenzofuran-5-yl.

[0022] Preferred as aryl is naphthyl, phenyl or phenyl mono- or disubstituted by alkoxy, phenyl, halogen, alkyl or trifluoromethyl, especially phenyl or phenyl-mono- or disubstituted by alkoxy, halogen or trifluoromethyl, and in particular phenyl.

[0023] Examples of substituted phenyl groups as R are, e.g. 4-chlorophen-l-yl, 3,4- dichlorophen- 1 -yl, 4-methoxyphen- 1 -yl, 4-methylphen- 1 -yl, 4-aminomethylphen- 1 -yl, 4- rnethoxyethylaminomethylphen- 1 -yl, 4-hydroxyethylaminomethylphen- 1 -yl, 4-hydroxyethyl- (methyl)-aminomethylphen- 1 -yl, 3-aminomethylphen- 1 -yl, 4-N-acetylaminomethylphen- 1 - yl, 4-aminophen-l-yl, 3-aminophen-l-yl, 2-aminophen-l-yl, 4-phenyl-phen-l-yl, 4- (imidazol- 1 -yl)-phen- 1 -yl, 4-(imidazol- 1 -ylmethyl)-phen- 1 -yl, 4-(morpholin- 1 -yl)-phen- 1 -yl, 4-(morpholin- 1 -ylmethyl)-phen- 1 -yl, 4-(2-methoxyethylaminomethyl)-phen- 1 -yl and 4-

(pyrrolidin-l-ylmethyl)-phen-l-yl, 4-(thiophenyl)-phen-l-yl, 4-(3-thiophenyl)-phen-l-yl, 4- (4-methylpiperazin-l-yl)-phen-l-yl, and 4-(piperidinyl)-phen-l-yl and 4-(pyridinyl)-phen-l- yl optionally substituted in the heterocyclic ring.

[0024] As used herein, the term "ATPase" refers to an enzyme that hydrolyzes ATP. For example, ATPases include proteins comprising molecular motors such as kinesins, myosins and dyneins. A "molecular motor" is a molecule that utilizes chemical energy to produce mechanical force or movement; molecular motors are particularly of interest in cytoskeletal systems. For further review, see, Vale and Kreis, 1993, Guidebook to the Cytoskeletal and Motor Proteins, New York: Oxford University Press; Goldstein, 1993, Ann. Rev. Genetics 27: 319-351; Mooseker and Cheney, 1995, Annu. Rev. Cell Biol. 11: 633-675; Burridge et al., 1996, Ann. Rev. Cell Dev. Biol. 12: 463-519.

[0025] As used herein, the term "contacting" refers to the process of bringing into contact at least two distinct species such that they can react or form a complex. It should be appreciated, however, the resulting complex can be produced directly from a complexation between the added species or from an intermediate formed from one or more of the added species which can be produced in the complex mixture. [0026] As used herein, the term "cycloalkyl" refers to a saturated or partially unsaturated, monocyclic, fused bicyclic or bridged polycyclic ring assembly containing from 3 to 12 ring atoms, or the number of atoms indicated. For example, C_3-8cycloalkyl includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and up to cyclooctyl.

[0027] As used herein, the term "haloalkyl" refers to alkyl as defined above where some or all of the hydrogen atoms are substituted with halogen atoms. Halogen (halo) preferably represents chloro or fluoro, but may also be bromo or iodo. For example, haloalkyl includes trifluoromethyl, fluoromethyl, 1,2,3,4,5-pentafiuoro-phenyl, etc. The term "perfluoro" defines a compound or radical which has at least two available hydrogens substituted with fluorine. For example, perfluorophenyl refers to 1,2,3,4,5-pentafluorophenyl, perfluoromethane refers to 1,1,1 -trifluoromethyl, and perfiuoromethoxy refers to 1,1,1 - trifiuoromethoxy.

[0028] As used herein, the term "halogen" refers to fluorine, chlorine, bromine and iodine.

[0029] As used herein, the term "heteroaryl" refers to a monocyclic or fused bicyclic or tricyclic aromatic ring assembly containing 5 to 16 ring atoms, where from 1 to 4 of the ring atoms are a heteroatom each selected from N, O or S. For example, heteroaryl includes pyridyl, indolyl, indazolyl, quinoxalinyl, quinolinyl, isoquinolinyl, benzothienyl, benzofuranyl, furanyl, pyrrolyl, thiazolyl, isothiazolyl, thiadiazolyl, benzothiazolyl, oxazolyl, isoxazolyl, oxadiazolyl, triazolyl, tetrazolyl, pyrazolyl, imidazolyl, thienyl, or any other radicals substituted, especially mono- or di-substituted, by e.g. alkyl, nitro or halogen.

Pyridyl represents 2-, 3- or 4-pyridyl, advantageously 2- or 3-pyridyl. Thienyl represents 2- or 3-thienyl. Quinolinyl represents preferably 2-, 3- or 4-quinolinyl. Isoquinolinyl represents preferably 1-, 3- or 4-isoquinolinyl. Benzopyranyl, benzothiopyranyl represents preferably 3- benzopyranyl or 3-benzothiopyranyl, respectively. Thiazolyl represents preferably 2- or 4- thiazolyl, and most preferred, 4-thiazolyl. Triazolyl is preferably 1-, 2- or 5-(l,2,4-triazolyl). Tetrazolyl is preferably 5-tetrazolyl.

[0030] Preferably, heteroaryl is imidazolyl, isothiazolyl, thiadiazolyl, oxadiazolyl, pyridyl, indolyl, quinolinyl, pyrrolyl, thiazolyl, isoxazolyl, triazolyl, tetrazolyl, pyrazolyl, thienyl, furanyl, benzothiazolyl, benzofuranyl, isoquinolinyl, benzothienyl, oxazolyl, indazolyl, or any of the radicals substituted, especially mono- or di-substituted.

[0031] As used herein, the term "heterocycle" refers to a ring system having from 3 ring members to about 20 ring members and from 1 to about 5 heteroatoms such as N, O and S. Additional heteroatoms can also be useful, including, but not limited to, B, Al, Si and P. The heteroatoms can also be oxidized, such as, but not limited to, -S(O)- and -S(O)₂-. For example, heterocycle includes, but is not limited to, tetrahydrofuranyl, tetrahydrothiophenyl, morpholino, pyrrolidinyl, pyrrolinyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, piperazinyl, piperidinyl, indolinyl, quinuclidinyl and l,4-dioxa-8-aza-spiro[4.5]dec-8-yl.

[0032] As used herein, the term "kinesin" refers to a class of motor protein found in cells. Kinesins useful in the present invention include, but are not limited to, Kin2, chromokinesin, KiflA, KSP, CENP-E, MCAK, HSET, RabK6, Kip3D, Kifl5, K335, Q475, D679, FLl, P166, H195, FL2, E433, R494, E658, L360, K491, S553, M329, T340, S405, V465, T488, Ml, M2, M3, M4, M5, M6, FL3, A2N370, A2M511, K519, E152.2, Q151.2, Q353, M472 and MKLPl.

[0033] As used herein, the term "linker" refers to a chemical moiety that links one part of the compound of the present invention to another part of the compound of the present invention. Exemplary linkers include, but are not limited to, alkyl and cycloalkyl groups. One of skill in the art will appreciate that other types of linkers are useful in the present invention.

[0034] As used herein, the term "modulating" refers to altering the chemical action of an enzyme, such as altering the conformation of the enzyme, or increasing or decreasing the activity of the enzyme.

II. Kinesin Modulators

A. Kinesins

[0035] In certain embodiments, the kinesin of the present invention includes mitotic kinesins. Mitotic kinesins are enzymes essential for assembly and function of the mitotic spindle, but are not generally part of other microtubule structures, such as nerve processes. Mitotic kinesins play essential roles during all phases of mitosis. These enzymes are

"molecular motors" that translate energy released by hydrolysis of ATP into mechanical force which drives the directional movement of cellular cargoes along microtubules. The catalytic domain sufficient for this task is a compact structure of approximately 340 amino acids. During mitosis, kinesins organize microtubules into the bipolar structure that is the mitotic spindle. Kinesins mediate movement of chromosomes along spindle microtubules, as well as structural changes in the mitotic spindle associated with specific phases of mitosis. Experimental perturbation of mitotic kinesin function causes malformation or dysfunction of the mitotic spindle, frequently resulting in cell cycle arrest. From both the biological and enzymatic perspectives, these enzymes are attractive targets for the discovery and development of novel anti-mitotic chemo therapeutics.

[0036] Examples of kinesins that can be assayed include, but are not limited to, Kin2, chromokinesin, KiflA, KSP, CENP-E, MCAK, HSET, RabK6, Kip3D, Kifl5, K335, Q475, D679, FLl, P166, H195, FL2, E433, R494, E658, L360, K491, S553, M329, T340, S405, V465, T488, Ml, M2, M3, M4, M5, M6, FL3, A2N370, A2M511, K519, E152.2, Q151.2, Q353, M472 and MKLPl. It is understood that unless a particular species is named, the term "kinesin" includes homologs thereof which may have different nomenclature among species. For example, the human homolog of KiflA is termed ATSV, the human homologue of Xenopus Eg5 is termed KSP, and human HSET corresponds to Chinese hamster CHO2.

[0037] As used herein, the term "kinesin protein activity" refers to one of the biological activities of a kinesin protein, including, but not limited to, its ability to affect ATP hydrolysis. Other activities include microtubule binding, gliding, polymerization/depolymerization (effects on microtubule dynamics), binding to other proteins of the spindle, binding to proteins involved in cell-cycle control, or serving as a substrate to other enzymes, such as kinases or proteases and specific kinesin cellular activities such as chromosome congregation, axonal transport, etc.

[0038] Methods of performing motility assays are well known to those of skill in the art (see, e.g., Hall et al., 1996, Biophys. J. 71 : 3467-3476, Turner et al., 1996, Anal. Biochem. 242 (l):20-5; Gittes et al., 1996, Biophys. J. 70(1): 418-29; Shirakawa et al., 1995, J. Exp. Biol. 198: 1809-15; Winkelmann et al., 1995, Biophys. J. 68: 2444-53; Winkelmann et al., 1995, Biophys. J. 68: 72S, and the like).

[0039] As will be appreciated by those in the art, the kinesins of the present invention can be made in a variety of ways, including by expressing a nucleic acid encoding the kinesin.

[0040] Numerous suitable methods for recombinant protein expression, including generation of expression vectors, generation of fusion proteins, introducing expression vectors into host cells, protein expression in host cells, and purification methods are known to those in the art and are described, for example, in the following textbooks: Sambrook et al., Molecular Cloning: A Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1989); Ausubel et al., Short Protocols in Molecular Biology (John Wiley & Sons, Inc., 1995); Harlow and Lane, Antibodies: A Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1988); O'Reilly et al., Baculovirus Expression Vectors: A Laboratory Manual (New York: Oxford University Press, 1994); Richardson, Baculovirus Expression Protocols (Totowa: Humana Press, 1995); Kriegler, Gene Transfer and Expression: A Laboratory Manual (New York: Oxford University Press, 1991); Roth, Protein Expression in Animal Cells, Methods in Cell Biology Vol. 43 (San Diego: Academic Press, 1994); Murray, Gene Transfer and Expression Protocols, Methods in Molecular Biology, VoI 7 (Clifton: Humana Press, 1991); Deutscher, Guide to Protein Purification, Methods in Enzymology Vol. 182 (San Diego: Academic Press, Inc., 1990); Harris and Angal, Protein Purification Methods: A Practical Approach (Oxford: IRL Press at Oxford University Press, 1994); Harris and Angal, Protein Purification Applications: A Practical Approach (Oxford: IRL Press at Oxford University Press, 1990); Rees et al., Protein Engineering, A Practical Approach (Oxford: IRL Press at Oxford University Press, 1992); and White, PCR Protocols, Methods in Molecular Biology, Vol. 15 (Totowa, Humana Press, 1993).

[0041] Both eukaryotic and prokaryotic host cell types are useful in the present invention for the expression of kinesins. Appropriate host cells include yeast, bacteria, archaebacteria, fungi, plant, insect and animal cells, including mammalian cells. Of particular interest are Drosophila melanogaster cells, Saccharomyces cerevisiae and other yeasts, E. coli, Bacillus subtilis, SF9 cells (and other related cells for use with baculo viral expression systems), C 129 cells, 293 cells, Neurospora, BHK, CHO, COS, Dictyostelium, etc.

[0042] In some embodiments, the kinesins are purified for use in the assays, as outlined herein, to provide substantially pure samples. The terms "substantially pure" or "isolated" as used herein mean that the protein is unaccompanied by at least some of the material with which it is normally associated in its natural state, preferably constituting at least about 0.5%, more preferably at least about 5% by weight of the total protein in a given sample. A substantially pure protein comprises at least about 75% by weight of the total protein, with at least about 80% being preferred, and at least about 90% being particularly preferred. Alternatively, the kinesin need not be substantially pure as long as the sample comprising the kinesin is substantially free of other components that can contribute to the production of ADP (or, in the case of indirect assays, other components which are subsequently assayed).

[0043] The kinesins may be isolated or purified in a variety of ways known to those skilled in the art depending on what other components are present in the sample. Standard purification methods include electrophoretic, molecular, immunological and chromatographic techniques, including ion exchange, hydrophobic, affinity, reverse-phase HPLC chromatography, and chromatofocusing. For example, the kinesin may be purified using a standard anti-target antibody column. Ultrafiltration and diafiltration techniques, in conjunction with protein concentration, are also useful. For general guidance in suitable purification techniques, see Scopes, R., Protein Purification, Springer-Verlag, N. Y. (1982).

[0044] Suitable purification schemes for some specific kinesins are outlined in U.S. Ser. No. 09/295,612, filed Apr. 20, 1999, hereby expressly incorporated herein in its entirety, along with referenced materials.

B. Compounds

[0045] The compounds used in the present invention were purchased from Albany Molecular. The compounds of the present invention can be prepared according to methods similar to those of U.S. Patent No. 4,336,264 and European Patent Publication No. 0 042 732.

III. Assay Methods and Screening Methods

[0046] The present invention provides methods for high throughput screening of modulators of kinesin activity, multi-time-point kinetic assay, enzymatic assays to detect ADP production using NADH, non-NADH coupled enzymatic assays to detect ADP production, and cell assays to determine in vitro potency of small molecule activators.

[0047] In some embodiments, the present invention provides a method of activating a kinesin comprising the step of contacting the kinesin with a compound of Formula I:

wherein R¹ is a member selected from the group consisting of halogen, C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₂-C₆ alkynyl, C₂-C₆ alkenyl, -N(R⁴,R⁵), cyano, -OR⁹, -SR⁹, a C₃-C₈ cycloalkyl substituted with 0-2 R⁶ groups, a C₆-C₁₂ aryl ring system substituted with 0-3 R⁷ groups, a heteroaryl ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R⁸ groups and a heterocyclic ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-5 R⁸ groups; L is a linker selected from the group consisting of a bond, C₁-C₆ alkyl and C₃-C₈ cycloalkyl; R² is a member selected from the group consisting of hydrogen and C₁-C₆ alkyl; alternatively, R^]-L and R² combine to form a heterocyclic ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R⁸ groups; A is a 5-membered heteroaryl ring system having 2-3 heteroatoms each independently selected from the group consisting of N, O and S; each R³ is independently a member selected from the group consisting of hydrogen, halogen, C₁-C₆ alkyl, C₁-C₆ alkoxy and C₃-C₈ cycloalkyl; alternatively, two R³ groups combine to form a member selected from the group consisting of a phenyl ring and a C₅-C₈ cycloalkyl; each of R⁴ and R⁵ is a member selected from the group consisting of hydrogen and C₁-C₆ alkyl; each R⁶ is independently a member selected from the group consisting of hydrogen and C₁-C₆ alkyl; alternatively, two R⁶ groups combine to form a phenyl group; each R⁷ is independently selected from the group consisting of hydrogen, -N(R⁴,R⁵), halogen, -Ci-C₆ alkoxy and Ci-C₆ alkyl; each R⁸ is independently selected from the group consisting of hydrogen and C₁-C₆ alkyl; R⁹ is a member selected from the group consisting of hydrogen, Ci-C₆ alkyl and a -Ci-C₄ alkyl-C₆-Ci₂ aryl ring system; and salts, hydrates, isomers and prodrugs thereof, thereby activating the kinesin.

[0048] In other embodiments, the present invention provides a method of activating a kinesin wherein A is a member selected from the group consisting of imidazole, pyrazole, isothiazole, isoxazole, thiadiazole, thiazole, oxazole, triazole and oxadiazole.

[0049] In another embodiments, the present invention provides a method of activating a kinesin comprising the step of contacting the kinesin with a compound of Formula Ia:

In a further embodiment, R¹ is a member selected from the group consisting OfC₂-C₆ alkenyl, C₂-C₆ alkynyl, cyano, -OR⁹, -SR⁹, a C₃-C₈ cycloalkyl, a C₆ aryl ring system substituted with 0-3 R⁷ groups, a heteroaryl ring system having 5-6 ring members and 1 heteroatom selected from the group consisting of N, O and S and a heterocyclic ring system having 5-6 ring members and 1 heteroatom selected from the group consisting of N, O and S; and R⁹ is a Ci-C₆ alkyl. In another embodiment, L is selected from the group consisting of a bond and Cj-C₆ alkyl; alternatively, R¹ -L and R² combine to form a heterocyclic ring system having 5-6 ring members and 1-2 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R⁸ groups. Li still another embodiment, R¹ -L and R² combine to form a ring system selected from the group consisting of pyrrolinyl, pyrrolidinyl, tetrahydropyridine, piperdinyl, thiomorpholinyl, azocane and indolinyl. In some other embodiments, each R³ is independently a member selected from the group consisting of Ci-C₆ alkyl and C₃-C₈ cycloalkyl. In yet another embodiment, each R³ is independently a member selected from the group consisting of t-butyl and cyclohexyl.

[0050] In some embodiments, the present invention provides a method of activating a kinesin wherein R¹ is a member selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyano, -NEt₂, -NMe₂, -OMe, -OEt, -OPr, -SMe, - SEt, -S-CH₂-Ph, cyclobutyl, cyclopentyl, cyclohexyl, bicyclo[3.3.0]octanyl, azocanyl, phenyl, pyridyl, piperidinyl, pyrrolidinyl and imidazolyl. In other embodiments, R¹ is a member selected from the group consisting of propenyl, propynyl, isobutenyl, -OMe, -SMe, cyclopropyl, phenyl, pyridyl, furanyl, thiophenyl and tetra-hydro-furanyl.

[0051] In still other embodiments, the present invention provides a method of activating a kinesin comprising the step of contacting KSP with a compound selected from the group consisting of:

[0052] In other embodiments, the present invention provides a method of activating a kinesin wherein the kinesin is KSP. hi some other embodiments, the compound has an AC40 of less than about 10 μM. hi still other embodiments, the compound has an AC40 of less than about 1 μM.

A. High Throughput Screening

[0053] The invention provides methods of screening candidate agents for the ability to serve as modulators of kinesin activity, hi some embodiments, high throughput screening (HTS) systems are used, which can include the use of robotic systems. The assays of the present invention offer the advantage that many samples can be processed in a short period of time. For example, plates having 96, 384, 1536 or as many wells as are commercially available can be used.

[0054] High throughput screening systems are commercially available (see, e.g., Zymark Corp., Hopkinton, Mass.; Air Technical Industries, Mentor, Ohio; Beckman Instruments, Inc., Fullerton, Calif; Precision Systems, Inc., Natick, Mass., etc.) These systems typically automate entire procedures including all sample and reagent pipetting, liquid dispensing, timed incubations, and final readings of the microplate in detector(s) appropriate for the assay. These configurable systems provide high throughput and rapid start up as well as a high degree of flexibility and customization. The manufacturers of such systems, i.e., Zymark Corp., provide detailed protocols for the various high throughput assays.

[0055] Generally a plurality of assay mixtures are run in parallel with different agent concentrations to obtain a differential response to the various concentrations. Typically, one of these concentrations serves as a negative control, i.e., at zero concentration or below the level of detection. However, in some embodiments, any concentration can be used as the control for comparative purposes.

[0056] Some high throughput screening methods that are provided involve providing a library containing a large number of compounds (candidate compounds) potentially having the desired activity. Such "combinatorial chemical libraries" are then screened in one or more assays, as described herein, to identify those library members (particular chemical species or subclasses) that display a desired characteristic activity. The compounds thus identified can serve as conventional "lead compounds" or can themselves be used as potential or actual therapeutics or agricultural compounds.

[0057] For example, in one embodiment, candidate agents are assayed in highly parallel fashion by using multiwell plates by placing the candidate agents either individually in wells or testing them in mixtures. Assay components, such as for example, a kinesin, coupling enzymes, substrates, and ATP can then be added to the wells and the absorbance or fluorescence of each well of the plate measured by a plate reader. A candidate agent which modulates the function of the kinesin is identified by an increase or decrease in the rate of ATP hydrolysis compared to a control assay in the absence of that candidate agent.

[0058] One exemplary HTS system is as follows. The system comprises a microplate input function which has a storage capacity matching a logical "batch" size determined by reagent consumption rates. The input device stores and, delivers on command, barcoded assay plates containing pre-dispensed samples, to a barcode reader positioned for convenient and rapid recording of the identifying barcode. The plates are stored in a sequential nested stack for maximizing storage density and capacity. The input device can be adjusted by computer control for varying plate dimensions. Following plate barcode reading, the input device can be adjusted by computer control for varying plate dimensions. Following plate barcode reading, the input device transports the plate into the pipetting device which contains the necessary reagents for the assay. Reagents are delivered to the assay plate with the pipetting device. Tip washing in between different reagents is performed to prevent carryover. A time dependent mixing procedure is performed after each reagent to effect a homogeneous solution of sample and reagents. The sequential addition of the reagents is delayed by an appropriate time to maximize reaction kinetics and readout levels. Immediately following the last reagent addition, a robotic manipulator transfers the assay plate into an optical interrogation device which records one or a series of measurements to yield a result which can be correlated to an activity associated with the assay. The timing of the robotic transfer is optimized by minimizing the delay between "last reagent" delivery and transfer to the optical interrogation device. Following the optical interrogation, the robotic manipulator removes the finished assay plates to a waste area and proceeds to transfer the next plate from pipetting device to optical interrogation device. Overlapping procedures of the input device, pipetting device and optical interrogation device are used to maximize throughput.

[0059] In one embodiment, approximately 1000 assays are performed per hour with very low false negative and false positive rates, with up to 10,000 assays an hour being preferred and more than 100,000 assays per hour being particularly preferred. In another embodiment, at least one or more of the steps regarding automated liquid handling or preferred assay design as described herein are included.

B. Multi-Time-Point Kinetic Assays

[0060] Some assays use a multi-time-point (kinetic) assay, with at least two data points being preferred. As will be appreciated by those in the art, the interval can be adjusted to correlate with the biological activity of the protein. In the case of multiple measurements the absolute rate of the protein activity can be determined, and such measurements have higher specificity particularly in the presence of candidate agents which have similar absorbance or fluorescence properties to that of the enzymatic readout. The kinetic assay reduces the false positive rate. In an additional aspect, the kinetic rates are normalized to several control wells on each assay plate. This allows for some variation in the activity of the kinesins and the stability of assay reagents over time and thus permits screening runs of several hours.

C. Coupled Enzyme Assays to Detect ADP Production Involving NADH

[0061] There are, for example, a number of enzymatic reactions known in the art which convert ADP to ATP. For example, pyruvate kinases are known to perform this conversion. Greengard, Nature 78:632-634 (1956); Hart, MoI. Pharmacol. 6(1):31-40 (1970). This is a useful method in that it allows the regeneration of ATP, which can then be used by the kinesin. In one embodiment, the level of activity of the enzymatic reaction is determined directly. For example, in a pyruvate kinase (PK) reaction, pyruvate or ATP can be measured by conventional methods known in the art.

[0062] In some embodiments, the level of activity of the enzymatic reaction which uses

ADP as a substrate is measured indirectly by being coupled to another reaction. For example, in one embodiment, the method further comprises a lactate dehydrogenase (LDH) reaction under conditions which normally allow the oxidation of NADH, wherein said lactate dehydrogenase reaction is dependent on the pyruvate kinase reaction. Measurement of enzymatic reactions by coupling is discussed, for example, in Greengard, Nature 178:632-634 (1956) and is further discussed below in regards to fluorescence methods.

[0063] It is understood that the methods provided herein can be applied to a varied array of kinesins and are not limited to cytoskeletal component systems. However, for illustrative purposes, an example of the present invention is to assay for modulators of the polymerized state of cytoskeletal filament proteins actin or tubulin. In this example, the candidate agent or mixture comprising at least one candidate agent is incubated with the filament protein under conditions that would normally promote either polymerization or depolymerization. A molecular motor that is activated by the filament is then added to the assay mixture and its activity is monitored by ADP or phosphate release as discussed above. Candidate agents which increase the fraction of the filament protein in a polymerized state will be identified by an increase in the motor ATPase and those which increase the fraction of the filament protein in a depolymerized state will be identified by a decrease in the motor ATPase.

[0064] When proteins that use ATP are included, the pyruvate kinase/lactate dehydrogenase embodiments are particularly preferred due to the advantage of ATP regeneration so that ATP concentration is constant over time.

[0065] Thus, some screening methods are designed to identify candidate agents that modulate the activity of a kinesin with ATP, phosphoenolpyruvate (PEP), pyruvate kinase (PK), lactate dehydrogenase (LDH) and NADH. The added pyruvate kinase catalyzes a reaction between PEP and the ADP produced by the kinesin to produce pyruvate and regenerate ATP. LDH then reduces the pyruvate that is formed to lactate, with the concomitant oxidation of NADH to NAD+. Assays are usually conducted in both the presence and absence of the candidate agent to determine if the candidate agent has an effect on the activity of the kinesin.

D. Non-NADH Coupled Enzyme Assays to Identify ADP Production

[0066] Other assays and screening methods utilize coupled enzyme systems but do not involve detecting the consumption (i.e., oxidation) of NADH. Instead, the coupled enzyme system (in a series of one or more coupled enzyme reactions) couples the utilization of ADP produced by the kinesin to the formation of a detectable compound that has a higher extinction coefficient, thereby providing increased sensitivity. The methods can utilize selected dye compounds, for instance, that produce a detectable product (e.g., a fluorescent compound) that has an extinction coefficient of at least 30,000 M^-1Cm^"1, 40,000 M^-1Cm^"1, 50,000 M^-1Cm^"1, or 60,000 M^-1Cm^"1, or any range therebetween.

[0067] In some methods, the ADP produced by the target enzyme is coupled to the regeneration of ATP and the formation of pyruvate (e.g., in a pyruvate kinase reaction). The oxidation of the pyruvate is coupled in turn to the formation of the detectable product.

[0068] An example of this type of assay generally involves combining a kinesin and an enzyme that can utilize the ADP produced directly or indirectly by the kinesin. In the coupled enzyme system in this particular assay, utilization of ADP by the enzyme is coupled to the conversion of a phosphorylated substrate to a dephosphorylated substrate by the enzyme, thereby resulting in the regeneration of ATP from ADP. Another reaction in the coupled system, the oxidation of the dephosphorylated substrate is coupled to the reduction of an oxidized substrate to form a reduced substrate. Finally, the reduced substrate is oxidized in another enzymatic reaction, with the concomitant reduction of a dye molecule (e.g., fluorophore) to form the detectable compound with the high extinction coefficient. Here, too, screening methods utilizing such assays are generally conducted in the presence and absence of a candidate agent to determine whether the candidate agent affects the activity of the kinesin.

[0069] Figure 1 depicts a specific example of this approach. In the particular assay shown in this figure, ATP, pyruvate kinase, PEP, pyruvate oxidase, a peroxidase (e.g., horse radish peroxidase, HRP) and 10-acetyl-3,7-dihydroxyphenoxazine (AMPLEX RED, Molecular Probes, Inc., Eugene, OR) are combined in an assay. ADP produced by the target enzyme is thus coupled to the conversion of PEP to pyruvate through the enzymatic activity of pyruvate kinase; this conversion also results in the regeneration of ATP from ADP. The oxidation of the pyruvate that is formed occurs with the reduction of oxygen to hydrogen peroxide via the enzymatic activity of pyruvate oxidase. The oxidation of the resulting hydrogen peroxide is coupled to the reduction of 10-acetyl-3,7-dihydroxyphenoxazine using horse radish peroxidase to form 3H-phenoxazin-3-one, 7-hydroxy (RESORUFIN, Molecular Probes, Inc., Eugene, OR), which can be excited at a wavelength of 563 nm and emits at a wavelength of 587 nm. The extinction coefficient for 3H-phenoxazin-3-one, 7-hydroxy is 58,000 M^-1Cm^"1. [0070] Assays of this general type in which the oxidation of pyruvate is coupled to the formation of a detectable product can be conducted with pyruvate oxidases from various sources. Suitable pyruvate oxidases include, for example, E. coli pyruvate oxidase (ICN) and Lactobacillus plantarum (Sigma).

[0071] The use of pyruvate oxidase from Lactobacillus plantarum can give significantly improved sensitivity as compared to pyruvate oxidases from other sources. This particular pyruvate oxidase utilizes phosphate as a cofactor. Assays conducted with this particular enzyme thus also include phosphate (e.g., sodium or potassium phosphate (mono or dibasic) at about 2 mM). hi assays conducted with pyruvate oxidases of this type that utilize phosphate as a cofactor, pyruvate oxidase catalyzes the reaction between pyruvate, oxygen and phosphate ion to form acetyl phosphate (rather than simply acetate as is the case with pyruvate oxidases that do not utilize phosphate as a cofactor) and hydrogen peroxide.

[0072] Other versions of 10-acetyl-3,7-dihydroxyphenoxazine such as Amp lex Deep Red (Molecular Probes), which has approximately twice the extinction coefficient of 10-acetyl- 3,7-dihydroxyphenoxazine, can be used for detection in this coupled system.

[0073] The assays can be conducted using two mixes that contain the necessary assay components to facilitate high throughput screening. For example, in some assays one mixture includes ATP, PEP, dye (e.g., 10-acetyl-3,7-dihydroxyphenoxazine (AMPLEX RED)) and kinesin. The second mixture contains pyruvate kinase, microtubules, pyruvate oxidase and a peroxidase enzyme (e.g., horse radish peroxidase), hi certain high throughput screening assays, samples containing one or more candidate agents are placed in sample wells on a multi-well plate. An aliquot from the first mixture is then transferred to each of the sample wells, followed by an aliquot from the second mixture. The resulting mixtures are subsequently mixed and signal (e.g., absorbance or fluorescence) measured at each of the wells.

[0074] Assays utilizing dyes with high extinction coefficients can be performed as end point assays, but the increased sensitivity possible with such dyes means that kinetic analyses can also be readily performed. The further increase in sensitivity that can be achieved using the Lactobacillus plantarum/phosphate cofactor combination further enhance the capabilities of conducting the assays in kinetic formats. As noted above, kinetic assays are ones in which measurements are made at multiple time points (e.g., a reading about every 1 minute). Further details regarding such assays are provided in the Examples below. Table 1. Table of Compound Assay Data

¹ AC40 data: +++, < 1 μM; ++, < 10 μM, +, > 10 μM; -, no data. IC50 data: +++, < 20 μm; ++, < 100 μM; +, > 100 μM; -, no data.

E. Cell assay

[0075] In vitro potency of small molecule activators is determined, for example, by assaying human ovarian cancer cells (SK-OV-3) for viability following a 72-hour exposure to a 9-point dilution series of compound. Cell viability is determined by measuring the absorbance of formazon, a product formed by the bioreduction of MTS/PMS, a commercially available reagent. Each point on the dose-response curve is calculated as a percent of untreated control cells at 72 hours minus background absorption (complete cell kill).

[0076] Antiproliferative compounds that have been successfully applied in the clinic to treatment of cancer (cancer chemotherapeutics) have GI50's that vary greatly. For example, in A549 cells, paclitaxel GI50 is 4 nM, doxorubicin is 63 nM, 5-fluorouracil is 1 μM, and hydroxyurea is 500 μM (data provided by National Cancer Institute, Developmental Therapeutic Program, http://dtp.nci.nih.gov/). Therefore, compounds that inhibit cellular proliferation, irrespective of the concentration demonstrating inhibition, have potential clinical usefulness. IV. Therapeutic Applications

A. Examples of Diseases and Disorders to be Treated

[0077] The chemical entities described herein can be used to treat cellular proliferation diseases. Such diseases include, but are not limited to, cancer (further discussed below), autoimmune disease, fungal disorders, arthritis, graft rejection, inflammatory bowel disease, cellular proliferation induced after medical procedures, including, but not limited to, surgery, angioplasty, and the like. Treatment includes inhibiting cellular proliferation. It is appreciated that in some cases the cells may not be in an abnormal state and still require treatment. Thus, in some embodiments, at least one chemical entity is administered to cells or individuals afflicted or subject to impending affliction with any one of these diseases or states.

[0078] The chemical entities provided herein can be used to treat cancer including solid tumors such as skin, breast, brain, cervical carcinomas, testicular carcinomas, etc. More particularly, cancers that can be treated include, but are not limited to:

• Cardiac: sarcoma (angiosarcoma, fibrosarcoma, rhabdomyosarcoma, liposarcoma), myxoma, rhabdomyoma, fibroma, lipoma and teratoma;

• Lung: bronchogenic carcinoma (squamous cell, undifferentiated small cell, undifferentiated large cell, adenocarcinoma), alveolar (bronchiolar) carcinoma, bronchial adenoma, sarcoma, lymphoma, chondromatous hamartoma, mesothelioma; • Gastrointestinal: esophagus (squamous cell carcinoma, adenocarcinoma, leiomyosarcoma, lymphoma), stomach (carcinoma, lymphoma, leiomyosarcoma), pancreas (ductal adenocarcinoma, insulinoma, glucagonoma, gastrinoma, carcinoid tumors, vipoma), small bowel (adenocarcinoma, lymphoma, carcinoid tumors, Karposi's sarcoma, leiomyoma, hemangioma, lipoma, neurofibroma, fibroma), large bowel (adenocarcinoma, tubular adenoma, villous adenoma, hamartoma, leiomyoma);

• Genitourinary tract: kidney (adenocarcinoma, Wilm's tumor [nephroblastoma], lymphoma, leukemia), bladder and urethra (squamous cell carcinoma, transitional cell carcinoma, adenocarcinoma), prostate (adenocarcinoma, sarcoma), testis (seminoma, teratoma, embryonal carcinoma, teratocarcinoma, choriocarcinoma, sarcoma, interstitial cell carcinoma, fibroma, fibroadenoma, adenomatoid tumors, lipoma);

• Liver: hepatoma (hepatocellular carcinoma), cholangiocarcinoma, hepatoblastoma, angiosarcoma, hepatocellular adenoma, hemangioma; • Bone: osteogenic sarcoma (osteosarcoma), fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma, Ewing's sarcoma, malignant lymphoma (reticulum cell sarcoma), multiple myeloma, malignant giant cell tumor chordoma, osteochronfroma (osteocartilaginous exostoses), benign chondroma, chondroblastoma, chondromyxofibroma, osteoid osteoma and giant cell tumors;

• Nervous system: skull (osteoma, hemangioma, granuloma, xanthoma, osteitis deformans), meninges (meningioma, meningiosarcoma, gliomatosis), brain (astrocytoma, medulloblastoma, glioma, ependymoma, germinoma [pinealoma], glioblastoma multiform, oligodendroglioma, schwannoma, retinoblastoma, congenital tumors), spinal cord neurofibroma, meningioma, glioma, sarcoma);

• Gynecological: uterus (endometrial carcinoma), cervix (cervical carcinoma, pre- tumor cervical dysplasia), ovaries (ovarian carcinoma [serous cystadenocarcinoma, mucinous cystadenocarcinoma, unclassified carcinoma], granulosa-thecal cell tumors, Sertoli-Leydig cell tumors, dysgerminoma, malignant tertoma), vulva (squamous cell carcinoma, intraepithelial carcinoma, adenocarcinoma, fibrosarcoma, melanoma), vagina (clear cell carcinoma, squamous cell carcinoma, botryoid sarcoma (embryonal rhabdomyosarcoma], fallopian tubes (carcinoma);

• Hematologic: blood (myeloid leukemia [acute and chronic], acute lymphoblastic leukemia, chronic lymphocytic leukemia, myeloproliferative diseases, multiple myeloma, myelodysplasia syndrome), Hodgkin's disease, non-Hodgkin's lymphoma

[malignant lymphoma];

• Skin: malignant melanoma, basal cell carcinoma, squamous cell carcinoma, Karposi's sarcoma, moles dysplastic nevi, lipoma, angioma, dermatofibroma, keloids, psoriasis; and • Adrenal glands: neuroblastoma.

[0079] As used herein, treatment of cancer includes treatment of cancerous cells, including cells afflicted by any one of the above-identified conditions. Thus, the term "cancerous cell" as provided herein, includes a cell afflicted by any one of the above identified conditions.

[0080] Disease states other than cancer which can be treated by the methods and compositions include restenosis, autoimmune disease, arthritis, graft rejection, inflammatory bowel disease, proliferation induced after medical procedures such as surgery, angioplasty, and the like, hi some methods, cells not in a hyper or hypo proliferation state (abnormal state) are the subject of treatment. For example, during wound healing, the cells may be proliferating "normally", but proliferation enhancement may be desired. Similarly, in the agriculture arena, cells may be in a "normal" state, but proliferation modulation may be desired to enhance a crop by directly enhancing growth of a crop, or by inhibiting the growth of a plant or organism which adversely affects the crop. Thus, therapeutic applications of the present invention include treatment of individuals afflicted or impending affliction with any one of these disorders or states.

[0081] In some embodiments, the present invention provides a method of treating a disease by activating a kinesin with a compound of Formula I. In other embodiments, the disease is a member selected from the group consisting of cancer, autoimmune disease, fungal disorders, arthritis, graft rejection, inflammatory bowel disease and cellular proliferation induced after medical procedures, hi still other embodiments, the cancer is a member selected from the group consisting of cardiac cancer, lung cancer, gastrointestinal cancer, genitourinary tract cancer, liver cancer, bone cancer, cancer of the nervous system, gynecological cancer, hematologic cancer, skin cancer and cancer of the adrenal glands.

B. Modulating Cellular Proliferation

[0082] Many clinical conditions or disease states are linked to abnormal cell proliferation. Accordingly, the present invention provides methods for treating such conditions or disease states by modulating cellular proliferation activities (e.g., kinesin bioactivities). Once a determination has been made regarding the abnormal proliferation state of a cell the compositions of the present invention (e.g., modulators of kinesin activity) can be administered as therapeutic agents.

[0083] The cellular proliferation modulator can be an anti-kinesin antibody (e.g., anti-L5 antibody), or other modulator. Usually such modulators are obtained by the screening methods described above. The modulation can be due to an alteration of a bioactivity involved in cellular proliferation, e.g., modulating motor activity. When administered to a cell, such cellular proliferation modulator (e.g., a kinesin inhibitor which binds to L5 region) can reduce or eliminate an endogenous cellular proliferation activity (e.g., kinesin ATPase activity). Methods of administering nucleic acids encoding peptide modulators are described by Brower et al., Nature Biotechnology, 16:1304-1305, 1998; Donnelly et al., Annu Rev Immunol, 15:617-48, 1997; as well as PCT/US93/03868, WO 91/04753, or WO 90/10448). [0084] In some embodiments, the present invention provides a method of modulating the ATPase activity of a domain of cellular proliferation protein KSP comprising the step of contacting KSP with a compound of Formula I.

C. Pharmaceutical Compositions: Dosages and Modes of Administration

[0085] The kinesin modulators of the present invention can be directly administered under sterile conditions to the patient to be treated. Modulators can be administered alone or as the active ingredient of a pharmaceutical formulation. Formulations typically comprise at least one active ingredient together with one or more acceptable carriers thereof. Each carrier should be both pharmaceutically and physiologically acceptable in the sense of being compatible with the other ingredients and not injurious to the patient. For example, the kinesin modulator is complexed with carrier proteins such as ovalbumin or serum albumin prior to their administration in order to enhance stability or pharmacological properties such as half-life. Furthermore, therapeutic formulations of this invention can be combined with or used in association with other therapeutic agents.

[0086] The therapeutic formulations can be delivered by any effective means which could be used for treatment. Depending on the specific kinesin modulators to be administered, the suitable means include oral, rectal, vaginal, nasal, pulmonary administration, or parenteral (including subcutaneous, intramuscular, intravenous and intradermal) infusion into the bloodstream, hi some instances, for example, in the treatment of wounds and inflammation, the kinesin proteins and modulators can be directly applied as a solution or spray.

[0087] The pharmaceutical compositions can be prepared in various forms, such as granules, tablets, pills, suppositories, capsules, suspensions, salves, lotions and the like. The concentration of therapeutically active compound in the formulation may vary from about 0.1-100% by weight. Therapeutic formulations are prepared by any methods well known in the art of pharmacy. See, e.g., Gilman et al., eds., Goodman and Gilman's: The

Pharmacological Bases of Therapeutics, 8th ed., Pergamon Press, 1990; and Remington's Pharmaceutical Sciences, 17th ed., Mack Publishing Co., Easton, P. a., 1990; Avis et al., eds., Pharmaceutical Dosage Forms: Parenteral Medications, published by Marcel Dekker, Inc., N. Y., 1993; Lieberman et al., eds., Pharmaceutical Dosage Forms: Tablets, published by Marcel Dekker, Inc., N. Y., 1990; and Lieberman et al., eds., Pharmaceutical Dosage Forms: Disperse Systems, published by Marcel Dekker, Inc., N.Y., 1990. [0088] The therapeutic formulations can conveniently be presented in unit dosage form and administered in a suitable therapeutic dose. A suitable therapeutic dose can be determined by any of the well known methods such as clinical studies on mammalian species to determine maximum tolerable dose and on normal human subjects to determine safe dosage. Except under certain circumstances when higher dosages may be required, the preferred dosage of a kinesin modulator usually lies within the range of from about 0.001 to about 1000 mg, more usually from about 0.01 to about 500 mg per day.

[0089] The preferred dosage and mode of administration of a kinesin modulator (e.g., a KSP inhibitor) can vary for different patients, depending upon factors that can be individually reviewed by the treating physician, such as the condition or conditions to be treated, the choice of composition to be administered, including the particular kinesin modulator, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the chosen route of administration). As a general rule, the quantity of a kinesin modulator administered is the smallest dosage which effectively and reliably prevents or minimizes the conditions of the patients. Therefore, the above dosage ranges are intended to provide general guidance and support for the teachings herein, but are not intended to limit the scope of the invention.

V. Examples

EXAMPLE 1 : A HIGH THROUGHPUT ASSAY FOR MODULATORS OF BASAL ATPASE ACTIVITY OF THE MOTOR PROTEIN KSP

[0090] This assay was based on the detection of ADP production from the basal ATPase activity of KSP (motor domain of human Ksp - residues Ml to L360). ADP production was monitored by a coupled enzyme system that included pyruvate kinase, pyruvate oxidase and horse radish peroxidase. Under the assay conditions described in this section, pyruvate kinase catalyzes the reaction between ADP and PEP to form ATP and pyruvate, respectively. Pyruvate oxidase in the presence of phosphate, then catalyzes an oxidation/reduction reaction between pyruvate and oxygen to form acetyl phosphate and hydrogen peroxide. The horse radish peroxidase subsequently catalyzes the oxidation/reduction reaction between hydrogen peroxide and the dye AMPLEX RED (10-acetyl-3,7-dihydroxyphenoxazine) from Molecular Probes to form the highly fluorescent molecule 3H-phenoxazin-3-one, 7-hydroxy (RESORUFIN, Molecular Probes, Eugene, OR), which can be detected at 587 nm. Assay Components

[0091] A KSP ATPase domain produced in Cytokinetics was used in the assay. The final 25 μl of assay solution contains the following: 10 ug/ml KSP, 6.8 ug/ml pyruvate kinase (Sigma), 4 U/ml pyruvate oxidase (Sigma), 0.5 U/ml horse radish peroxidase (Sigma), 0.1 mM ATP, 0.1 mM PEP, 0.05 mM AMPLEX RED, 2 mM Sodium Phosphate, 50 ppm antifoam 298 (Sigma) and 0.1 mg/ml BSA in 25 mM pipes buffer, pH 6.8, 2 mM MgCl₂.

[0092] The assays solutions were prepared as indicated in the following chart:

Compound Plates/Instrumentation [0093] Potential chemical modulators of KSP were dissolved in DMSO at a concentration of approximately 1 mg/ml, and 0.5 μl of each solution dispensed into a single well of a black 384 well plate (Costar, Corning). On each plate, there are at least 16 wells into which pure DMSO (without a candidate compound) is dispensed. These wells serve as negative controls for comparison to the potential chemical modulators on that plate. The compound plates are made in advance and stored at 4 °C, and each plate is labeled with a bar code which is used to identify the compounds on a given plate.

Assay Performance

[0094] A stack of compound plates is placed in the plate storage devices and plates are transferred one at a time to the automated pipetting device by the plate carrier of the Plat Stak. Each of the 384 wells is then filled with 12.5 μl of solution 2 listed on the chart above. The pipette tips are washed with a solution of 0.001% antifoam in deionized water. To start the assay, 12.5 μl of solution 1 is then added to each well. The solution is then mixed by pipetting the solution up and down 10 times. The plate is then transferred to the plate reader by the robotic arm. In the plate reader, the plate is exposed to 563 run light to excite AMPLEX RED and 10 fluorescence measurements at 587 ran are taken at 50 second intervals to produce a 8 minute kinetic read for each well. While one plate is being read, the next plate is transferred to the pipetting device and prepared up to but not including the addition of the second solution. When the plate read is complete, the robotic arm transfers the plate to a waste chute and simultaneously the second solution is pipetted into the next plate so that it can be transferred to the reader to complete the cycle. The entire assay is run at room temperature about 20 °C.

Data Analysis

[0095] Following data acquisition, the maximum rate of the fluorescence change is calculated for each well and normalized to the average of the control wells (without compound and with DMSO) which were present on the same plate. The normalized rates are then entered into an Oracle database, and this allows them to be correlated with the potential chemical modulators. On each plate, the coefficient of variation of the slopes for the control wells ranges from 4-8%. Quality control is assured by monitoring for a minimal initial absorbance and a linear absorbance change.

Features [0096] The improved sensitivity possible using dyes such as AMPLEX RED means that very small ATPase activities can be measured using assays such as described in this example and that the amount of reagent consumed in the assays can be reduced by about 100-fold relative to certain NADH-based assays. For instance, ATPase activities as low as about 0.0004 uM/s can be measured. Furthermore, because the excitation and emission wavelengths are at 560 and 580 nm, respectively, interference from fluorescent compounds that can be problematic in the near UV region is reduced.

[0097] The assay components and the performance of the assay are optimized together to match the overall read time with the rate at which ADP is produced by KSP. In this example, the rate of fluorescence intensity change is approximately 9000 RFU/Second. This corresponds to the production of approximately 0.00035 μM ADP/sec. In addition to optimizing the rate of ADP production, the read time should be long enough for the rate of AMPLEX RED consumption to reach steady state beyond an initial lag time of several seconds. In some cases, the order of addition of the reagents can have a significant affect on the rate of ADP production. In this example, the optimal rate is achieved by premixing all reagents except for the compound of interest and ATP.

EXAMPLE 2: A HIGH THROUGHPUT ASSAY FOR MODULATORS OF THE MOTOR PROTEIN KSP

[0098] This assay was based on the detection of ADP production from the microtubule stimulated ATPase activity of the motor protein KSP. ADP production was monitored by a coupled enzyme system that included pyruvate kinase, pyruvate oxidase and horse radish peroxidase. Under the assay conditions described in this section, pyruvate kinase catalyzes the reaction between ADP and PEP to form ATP and pyruvate, respectively. Pyruvate oxidase in the presence of phosphate, then catalyzes an oxidation/reduction reaction between pyruvate and oxygen to form acetyl phosphate and hydrogen peroxide. The horse radish peroxidase subsequently catalyzes the oxidation/reduction reaction between hydrogen peroxide and the dye AMPLEX RED (10-acetyl-3,7-dihydroxyphenoxazine) from Molecular Probes to form the highly fluorescent molecule 3H-phenoxazin-3-one, 7-hydroxy (RESORUFIN, Molecular Probes, Eugene, OR), which can be detected at 587 nm.

Assay Components

[0099] A KSP ATPase (motor domain of human Ksp - residues Ml to L360) produced at Cytokinetics was used in the assay. The final 25 μl of assay solution contains the following: 0.4 ug/ml KSP, 100 μg/ml microtubules assembled from porcine brain tubulin prepared at Cytokinetics, 6.8 ug/ml pyruvate kinase (Sigma), 4 U/ml pyruvate oxidase (Sigma), 0.5 U/ml horse radish peroxidase (Sigma), 0.25 mM ATP, 0.1 mM PEP, 0.05 mM AMPLEX RED, 5 μM paclitaxel, 50 ppm antifoam 298 (Sigma) and 0.1 mg/nil BSA in 25 mM pipes buffer, pH 6.8, 2 mM MgCl₂.

[0100] The assays solutions were prepared as indicated in the following chart

Compound Plates/Instrumentation

[0101] Potential chemical modulators of KSP were dissolved in DMSO at a concentration of approximately 1 mg/ml, and 0.5 μl of each solution dispensed into a single well of a black 384 well plate (Costar, Corning). On each plate, there are at least 16 wells into which pure DMSO (without a candidate compound) is dispensed. These wells serve as negative controls for comparison to the potential chemical modulators on that plate. The compound plates are made in advance and stored at 4 °C, and each plate is labeled with a bar code which is used to identify the compounds on a given plate.

[0102] The robotic system that runs the assay consists of a plate storage and retrieval device (Plate Stak, CCS Packard), a 96 channel automated pipetting device (Multimek, Beckman), a robotic arm (Twister, Zymark), and a plate reader for absorbance (Ultramark, BioRad). The system is controlled by a custom-built software application.

Assay Performance

[0103] A stack of compound plates is placed in the plate storage devices and plates are transferred one at a time to the automated pipetting device by the plate carrier of the Plat Stak. Each of the 384 wells is then filled with 12.5 μl of solution 2 listed on the chart above. The pipette tips are washed with a solution of 0.001% antifoam in deionized water. To start the assay, 12.5 μl of solution 1 is then added to each well. The solution is then mixed by pipetting the solution up and down 10 times. The plate is then transferred to the plate reader by the robotic arm. In the plate reader, the plate is exposed to 563 run light to excite AMPLEX RED and 10 fluorescence measurements at 587 nm are taken at 50 second intervals to produce a 8 minute kinetic read for each well. While one plate is being read, the next plate is transferred to the pipetting device and prepared up to but not including the addition of the second solution. When the plate read is complete, the robotic arm transfers the plate to a waste chute and simultaneously the second solution is pipetted into the next plate so that it can be transferred to the reader to complete the cycle. The entire assay is run at room temperature about 20 °C.

Data Analysis

[0104] Following data acquisition, the maximum rate of the fluorescence change is calculated for each well and normalized to the average of the control wells (without compound and with DMSO) which were present on the same plate. The normalized rates are then entered into an Oracle database, and this allows them to be correlated with the potential chemical modulators. On each plate, the coefficient of variation of the slopes for the control wells ranges from 4-8%. Quality control is assured by monitoring for a minimal initial absorbance and a linear absorbance change.

Features [0105] The improved sensitivity possible using dyes such as AMPLEX RED means that very low ATPase activity can be measured using assays such as described in this example and that the amount of reagent consumed in the assays can be reduced by about 100-fold relative to certain NADH-based assays. For instance, ATPase activities as low as about 0.003 s-1 can be measured. Furthermore, because the excitation and emission wavelengths are at 560 and 580 nm, respectively, interference from fluorescent compounds that can be problematic in the near UV region is reduced.

[0106] The assay components and the performance of the assay are optimized together to match the overall read time with the rate at which ADP is produced by KSP. In this example, the rate of fluorescence intensity change is approximately 25000 RFU/Second. This corresponds to the production of approximately 0.00085 μM ADP/sec. In addition to optimizing the rate of ADP production, the read time should be long enough for the rate of AMPLEX RED consumption to reach steady state beyond an initial lag time of several seconds. In some cases, the order of addition of the reagents can have a significant affect on the rate of ADP production. In this example, the optimal rate is achieved by premixing all reagents except for the compound of interest and ATP.

EXAMPLE 3: CELLULAR IC50s

[0107] In vitro potency of small molecule activators is determined by assaying human ovarian cancer cells (SK-OV-3) for viability following a 72-hour exposure to a 10-point dilution series of compound. Cell viability is determined by measuring the absorbance of formazon, a product formed by the bioreduction of MTS/PMS, a commercially available reagent. Each point on the dose-response curve is calculated as a percent of untreated control cells at 72 hours minus background absorption (complete cell kill).

Materials and Solutions:

[0108] Cells: SK-OV-3, Ovarian Cancer (human). Media: RPMI medium + 5% Fetal Bovine Serum + 2mM L-glutamine. Colorimetric Agent for Determining Cell Viability: Promega MTS tetrazolium compound. Control Compound for max cell kill: Topotecan, IuM.

Procedure:

Day 1 - Cell Plating [0109] Wash adherent SK-OV-3 cells in a Tl 75 Flask with 1OmLs of PBS and add 2mLs of 0.25% trypsin. Incubate for 5 minutes at 37°C. Rinse cells from flask using 8mL of media (RPMI medium+ 5%FBS) and transfer to fresh 5OmL sterile conical. Determine cell concentration by adding lOOuL of cell suspension to 90OuL of ViaCount reagent (Guava Technology), an isotonic diluent in a micro-centrifuge tube. Place vial in Guava cell counter and set readout to acquire. Record cell count and calculate the appropriate volume of cells to achieve 300 cells/20uL.

[0110] Add 20ul of cell suspension (300 cells/well) to all wells of 384-well CoStar plates.

[0111] Incubate for 24 hours at 37°C, 100% humidity, and 5% CO2, allowing the cells to adhere to the plates.

Day 2 - Compound addition [0112] In a sterile 384-well CoStar assay plate, dispense 5ul of compound at 250X highest desired concentration to wells Bl l-Ol 1 (except for Hl 1 control well) and B 14-014 (27 compounds per plate, edge wells are not used due to evaporation). 250X compound is used to ensure final uniform concentration of vehicle (DMSO) on cells is 0.4%. Dilute 14.3ul of 1OmM Topotecan into 10ml of 5.8% DMSO in RPMI medium giving a final concentration of 14.3uM stock. Add 1.5ul of this Topotecan stock to 20ul of cell in column 13 (rows B-O) giving a final Topotecan concentration on cells of IuM. ODs from these wells will be used to subtract out for background absorbance of dead cells and vehicle. Add 80ul of medium without DMSO to each compound well in column 11 and 14. Add 40ul medium (containing 5.8% DMSO) to all remaining wells. Serially dilute compound 2-fold from column 11 to column 2 by transferring 40ul from one column to the next taking care to mix thoroughly each time. Similarly serially dilute compound 2-fold from column 14 to column 23.

[0113] For each compound plate, add 1.5uL compound-containing medium in duplicate from the compound plate wells to the corresponding cell plates wells. Incubate plates for 72 hours at 37°C, 100% humidity, and 5% CO2.

Day 5 - MTS Addition and OD Reading [0114] After 72 hours of incubation with drug, remove plates from incubator and add 4.5ul MTS / PMS to each well. Incubate plates for 120 minutes at 37°C, 100% humidity, 5% CO2. Read ODs at 490nm after a 5 second shaking cycle in a 384- well spectrophotometer.

[0115] For Data analysis, calculate normalized % of control (absorbance-background), and use XLfit to generate a dose-response curve. Certain chemical entities described herein showed activity when tested by this method.

EXAMPLE 4: APPLICATION OF A MITOTIC KTNESIN ACTIVATOR [0116] Human tumor cells SK-OV-3 (ovarian) were plated in 96-well plates at densities of 4,000 cells per well, allowed to adhere for 24 hours, and treated with various concentrations of the test compounds for 24 hours. Cells were fixed in 4% formaldehyde and stained with antitubulin antibodies (subsequently recognized using fluorescently-labeled secondary antibody) and Hoechst dye (which stains DNA).

[0117] Visual inspection revealed that the compounds caused cell cycle arrest.

EXAMPLE 5: INHIBITION OF CELLULAR PROLIFERATION IN TUMOR CELL LINES TREATED WITH MITOTIC KINESIN ACTIVATORS. [0118] Cells were plated in 96-well plates at densities from 1000-2500 cells/well of a 96- well plate and allowed to adhere/grow for 24 hours. They were then treated with various concentrations of drug for 48 hours. The time at which compounds are added is considered TO. A tetrazolium-based assay using the reagent 3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) (U.S. Patent No. 5,185,450) (see Promega product catalog #G3580, CellTiter 96® AQueous One Solution Cell Proliferation Assay) was used to determine the number of viable cells at TO and the number of cells remaining after 48 hours compound exposure. The number of cells remaining after 48 hours was compared to the number of viable cells at the time of drug addition, allowing for calculation of growth inhibition.

[0119] The growth over 48 hours of cells in control wells that had been treated with vehicle only (0.25% DMSO) is considered 100% growth and the growth of cells in wells with compounds is compared to this. Mitotic kinesin activators inhibited cell proliferation in human ovarian tumor cell lines (SK-OV-3).

[0120] A Gi50 was calculated by plotting the concentration of compound in μM vs the percentage of cell growth of cell growth in treated wells. The Gi50 calculated for the compounds is the estimated concentration at which growth is inhibited by 50% compared to control, i.e., the concentration at which:

100 x [(Treated48 - TO) / (Control48 - TO)] = 50.

[0121] All concentrations of compounds are tested in duplicate and controls are averaged over 12 wells. A very similar 96-well plate layout and Gi50 calculation scheme is used by the National Cancer Institute (see Monks, et al., J. Natl. Cancer Inst. 83 :757-766 (1991 )).

However, the method by which the National Cancer Institute quantitates cell number does not use MTS, but instead employs alternative methods.

EXAMPLE 6: COMPOUND PREPARATION

[0122] The compounds used in the present invention were purchased from Albany Molecular. The compounds of the present invention can be prepared according to methods similar to those of U.S. Patent No. 4,336,264 and European Patent Publication No. 0 042 732.

[0123] It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes to the same extent as if each individual publication, patent or patent application were specifically and individually indicated to be so incorporated by reference.

Claims

WHAT IS CLAIMED IS:

L A method of activating a kinesin comprising the step of contacting said kinesin with a compound of Formula I:

wherein R¹ is a member selected from the group consisting of halogen, C₁-C₆ alkyl, Ci-C₆ haloalkyl, C₂-C₆ alkynyl, C₂-C₆ alkenyl, -N(R⁴,R⁵), cyano, -OR⁹, -SR⁹, a C₃-C₈ cycloalkyl substituted with 0-2 R⁶ groups, a C₆-C₁₂ aryl ring system substituted with 0-3 R⁷ groups, a heteroaryl ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R⁸ groups and a heterocyclic ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-5 R⁸ groups; L is a linker selected from the group consisting of a bond, Ci-C₆ alkyl and C₃-C₈ cycloalkyl; R² is a member selected from the group consisting of hydrogen and Ci-C₆ alkyl; alternatively, R¹ -L and R² combine to form a heterocyclic ring system having 5-10 ring members and 1-3 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R⁸ groups; A is a 5-membered heteroaryl ring system having 2-3 heteroatoms each independently selected from the group consisting of N, O and S; each R³ is independently a member selected from the group consisting of hydrogen, halogen, Ci-C₆ alkyl, CpC₆ alkoxy and C₃-C₈ cycloalkyl; alternatively, two R³ groups combine to form a member selected from the group consisting of a phenyl ring and a C₅-C₈ cycloalkyl; each of R⁴ and R⁵ is a member selected from the group consisting of hydrogen and Ci-C₆ alkyl; each R⁶ is independently a member selected from the group consisting of hydrogen and Ci-C₆ alkyl; alternatively, two R⁶ groups combine to form a phenyl group; each R⁷ is independently selected from the group consisting of hydrogen, -N(R⁴,R⁵), halogen, -Ci-C₆ alkoxy and Ci-C₆ alkyl; each R⁸ is independently selected from the group consisting of hydrogen and Ci-C₆ alkyl; R⁹ is a member selected from the group consisting of hydrogen, Ci-C₆ alkyl and a -Ci-C₄ alkyl-C₆-Ci₂ aryl ring system; and salts, hydrates, isomers and prodrugs thereof, thereby activating said kinesin.

2. The method of claim 1, wherein A is a member selected from the group consisting of imidazole, pyrazole, isothiazole, isoxazole, thiadiazole, thiazole, oxazole, triazole and oxadiazole.

3. The method of claim 2, comprising the step of contacting said kinesin with a compound of Formula Ia:

4. The method of claim 3, wherein R¹ is a member selected from the group consisting of C₂-C₆ alkenyl, C₂-C₆ alkynyl, cyano, -OR⁹, -SR⁹, a C₃-C₈ cycloalkyl, a C₆ aryl ring system substituted with 0-3 R⁷ groups, a heteroaryl ring system having 5-6 ring members and 1 heteroatom selected from the group consisting of N, O and S and a heterocyclic ring system having 5-6 ring members and 1 heteroatom selected from the group consisting of N, O and S; and R⁹ is a Ci-C₆ alkyl.

5. The method of claim 3, wherein L is selected from the group consisting of a bond and Ci-C₆ alkyl; alternatively, R¹ -L and R² combine to form a heterocyclic ring system having 5-6 ring members and 1-2 heteroatoms each independently selected from the group consisting of N, O and S and substituted with 0-2 R⁸ groups.

6. The method of claim 5, wherein R^!-L and R² combine to form a ring system selected from the group consisting of pyrrolinyl, pyrrolidinyl, tetrahydropyridine, piperdinyl, thiomorpholinyl, azocane and indolinyl.

7. The method of claim 3, wherein each R³ is independently a member selected from the group consisting of Ci-C₆ alkyl and C₃-C₈ cycloalkyl.

8. The method of claim 7, wherein each R is independently a member selected from the group consisting of t-butyl and cyclohexyl.

9. The method of claim 3, wherein R¹ is a member selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyano, - NEt₂, -NMe₂, -OMe, -OEt, -OPr, -SMe, -SEt, -S-CH₂-Ph, cyclobutyl, cyclopentyl, cyclohexyl, bicyclo[3.3.0]octanyl, azocanyl, phenyl, pyridyl, piperidinyl, pyrrolidinyl and imidazolyl.

10. The method of claim 3, wherein R¹ is a member selected from the group consisting of propenyl, propynyl, isobutenyl, -OMe, -SMe, cyclopropyl, phenyl, pyridyl, furanyl, thiophenyl and tetra-hydro-furanyl.

11. The method of claim 10, comprising the step of contacting KSP with a compound selected from the group consisting of:

Yl. The method of claim 1, wherein said kinesin is KSP.

13. The method of claim 1, wherein said compound has an AC40 of less than about 10 μM.

14. The method of claim 1 , wherein said compound has an AC40 of less than about 1 μM.

15. A method of treating a disease by activating a kinesin with a compound of claim 1.

16. The method of claim 15, wherein said disease is a member selected from the group consisting of cancer, autoimmune disease, fungal disorders, arthritis, graft rejection, inflammatory bowel disease and cellular proliferation induced after medical procedures.

17. The method of claim 16, wherein said cancer is a member selected from the group consisting of cardiac cancer, lung cancer, gastrointestinal cancer, genitourinary tract cancer, liver cancer, bone cancer, cancer of the nervous system, gynecological cancer, hematologic cancer, skin cancer and cancer of the adrenal glands.

18. A method of modulating the ATPase activity of a domain of cellular proliferation protein KSP comprising the step of contacting KSP with a compound of claim 1.