Tubulin Inhibitors
The present invention refers to novel molecules which inhibit the polymerization of the tubulin skeleton of cancer cells.
It is the objective of the present invention to provide novel cytotoxic molecules which preferably show a high potent activity against cancer cell lines and strong binding
affinities to tubulin, thus, being preferably able to kill cancer cells.
The present invention provides one or more compounds of formula (I) :
(I)
wherein
R is H or an alkyl , alkenyl, alkynyl, CO-alkyl or heteroalkyl group, all of which may optionally be substituted;
R
' is H or an alkyl, alkenyl, alkynyl, CO-alkyl or heteroalkyl group, all of which may optionally be substituted;
R' ' is a group of formula CH
2OH or
n is O, 1 , 2, 3, 4 or 5 ;
Y is independently optionally substituted alkyl (e.g. methyl), heteroalkyl (e.g. MeO) , halogen, CN, N02 or OH; or a pharmacologically acceptable salt, solvate, hydrate or a pharmacologically acceptable formulation thereof.
The expression alkyl refers to a saturated, straight-chain or branched hydrocarbon group that contains from 1 to 20 carbon atoms, preferably from 1 to 12 carbon atoms, especially from 1 to 6 (e.g. 1, 2, 3 or 4) carbon atoms, for example methyl, ethyl, propyl, isopropyl, isobutyl, n-butyl, sek-butyl, tert- butyl , n-pentyl, 2 , 2—dimethylpropyl , 2 -methylbutyl , n-hexyl, 2 , 2 -dimethylbutyl or 2 , 3 -dimethylbutyl .
The expressions alkenyl and alkynyl refer to at least
partially unsaturated, straight-chain or branched hydrocarbon groups that contain from 2 to 20 carbon atoms, preferably from 2 to 12 carbon atoms, especially from 2 to 6 (e.g. 2, 3 or 4) carbon atoms, for example an ethenyl, allyl, acetylenyl, propargyl, isoprenyl or hex-2-enyl group. Preferably, alkenyl groups have one or two (especially preferably one) double bond(s), and alkynyl groups have one or two (especially preferably one) triple bond(s).
Furthermore, the terms alkyl, alkenyl and alkynyl refer to groups in which one or more hydrogen atoms (e.g. 1, 2 or 3 hydrogen atoms) have been replaced by a halogen atom
(preferably F or Cl) such as, for example, a 2,2,2- trichloroethyl or a trifluoromethyl group.
The expression heteroalkyl refers to an alkyl, alkenyl or alkynyl group in which one or more (preferably 1, 2 or 3) carbon atoms have been replaced by an oxygen, nitrogen, phosphorus, boron, selenium, silicon or sulfur atom
(preferably by an oxygen, sulfur or nitrogen atom) . The expression heteroalkyl furthermore refers to a carboxylic acid or to a group derived from a carboxylic acid, such as, for example, acyl (alkyl-CO-), acylalkyl, alkoxycarbonyl , acyloxy, acyloxyalkyl , carboxyalkylamide or alkoxycarbonyloxy .
Preferably, a heteroalkyl group contains from 1 to 12 carbon atoms and from 1 to 4 hetero atoms selected from oxygen, nitrogen and sulphur (especially oxygen and nitrogen) .
Especially preferably, a heteroalkyl group contains from 1 to 6 (e.g. 1, 2, 3 or 4) carbon atoms and 1, 2 or 3 (especially 1 or 2) hetero atoms selected from oxygen, nitrogen and sulphur (especially oxygen and nitrogen)
Examples of heteroalkyl groups are groups of formulae:
Ra-0-Ya-, Ra-S-Ya-, Ra-N (Rb) -Ya- , Ra-C0-Ya-, Ra-0-CO-Ya-,
Ra-C0-0-Ya-, Ra-CO-N(Rb) -Ya- , Ra-N (Rb) -CO-Ya- , Ra-0-CO-N (Rb) -Y - , Ra-N(Rb) -CO-0-Ya- , Ra-N (Rb) -CO-N (Rc) -Ya- , Ra-0-CO-0-Ya- ,
Ra-N(Rb) -C(=NRd) -N(RC) -Ya- , R -CS-Ya-, Ra-0-CS-Ya-, Ra-CS-0-Ya-, Ra-CS-N(Rb) -Ya-, Ra-N(Rb) -CS-Ya- , Ra-0-CS -N (Rb) -Ya- ,
Ra-N(Rb) -CS-0-Ya- , Ra-N(Rb) -CS-N(RC) -Ya- , Ra-0-CS -O-Ya- ,
Ra - S - CO-Ya-, Ra - CO - S-Ya-, Ra-S-CO-N(Rb) -Ya-, Ra-N (Rb) -CO-S-Ya- , Ra-S-CO-0-Ya- , Ra-0-CO-S-Ya- , Ra- S - CO - S-Ya- , Ra-S- CS-Ya-,
Ra - CS - S-Ya-, Ra-S-CS-N(Rb) -Ya- , Ra-N (Rb) - CS - S-Ya- , Ra-S-CS-0-Ya- , Ra-0-CS- S-Ya- , wherein Ra is a hydrogen atom, a Ci - C6 alkyl, a C2-C6 alkenyl or a C2-C6 alkynyl group; Rb is a hydrogen atom, a Ci - C6 alkyl, a C2-C6 alkenyl or a C2-C6 alkynyl group; Rc is a hydrogen atom, a Ci - C6 alkyl, a C2-C6 alkenyl or a C2-C6 alkynyl group; Rd is a hydrogen atom, a Ci - C6 alkyl, a C2-C6 alkenyl or a C2-C6 alkynyl group and Ya is a direct bond, a Ci -C6 alkylene, a C2-C6 alkenylene or a C2-C6 alkynylene group, wherein each heteroalkyl group contains at least one carbon atom and one or more hydrogen atoms may be replaced by halogen (e.g. fluorine or chlorine) atoms.
Specific examples of heteroalkyl groups are methoxy,
trifluoromethoxy, ethoxy, n-propyloxy, isopropyloxy, tert- butyloxy, methoxymethyl , ethoxymethyl , -CH2CH2OH, -CH2OH, methoxyethyl , methylamino, ethylamino, dimethylamino,
diethylamino, isopropylethylamino , methylamino methyl, ethylamino methyl, diisopropylamino ethyl, enol ether, dimethyl - amino methyl, dimethylamino ethyl, acetyl, propionyl ,
butyryloxy, acetyloxy, methoxycarbonyl , ethoxycarbonyl , N- ethyl-N-methylcarbamoyl or N-methylcarbamoyl . Further examples of heteroalkyl groups are nitrile, isonitrile, cyanate, thio- cyanate, isocyanate, isothiocyanate and alkylnitrile groups.
The term "optionally substituted" relates to groups, wherein one or more hydrogen atoms have been replaced by fluorine, chlorine, bromine or iodine atoms or by OH, =0, SH, =S, NH2, =NH or N02 groups. This term relates further to groups, which can be exclusively or additionally substituted with
unsubstituted Ci-C6 alkyl, C2-C6 alkenyl , C2-C6 alkinyl or Cx-C6 heteroalkyl groups .
Protecting groups are known to a person skilled in the art and e.g. described in P . J. Kocienski, Protecting Groups, Georg Thieme Verlag, Stuttgart, 1994 and in T. W. Greene, P. G. M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, New York, 1999. Common amino protecting groups are e.g. t-butyloxycarbonyl (Boc) , t-butyldimethylsilyl (TBS) ,
benzyloxycarbonyl (Cbz, Z) , benzyl (Bn) , benzoyl (Bz) ,
fluorenylmethyloxycarbonyl (Fmoc) , allyloxycarbonyl (Alloc) , triethylsilyl (TES) , trichlorethyloxycarbonyl (Troc) , acetyl or trifluoracetyl .
Compounds of formula (I) may comprise several chiral centers depending on their substitution pattern. The present invention relates to all defined enantio- and diastereoisomers as well as their mixtures in all ratios. Moreover the present
invention relates to all cis/trans isomers of compounds of general formula (I) as well as their mixtures. Moreover the present invention relates to all tautomeric forms of compounds of the general formula (I) .
Preferably, R is H or Ci-C6 alkyl; especially a methyl or a propyl group .
Preferably, R' is -CO-alkyl, alkyl or heteroalkyl, especially Acetyl (Ac) or -CH2OCH3.
Preferably,
Further preferably, R
" is -CH
2OH.
Perferably, n is 0.
Especially preferred are compounds of formula (I) wherein: R is Ci - C6 alkyl, especially - CH3 , ethyl, propyl, butyl, isopropyl, isobutyl, n-pentyl, n-hexyl;
R
' is -CO-alkyl or heteroalkyl , especially -CO-CH
3 or -CH
2OCH
3;
(especially -CH
2OH) and
n is 0.
Examples of pharmacologically acceptable salts of the
compounds of formula (I) are salts of physiologically acceptable mineral acids,, such as hydrochloric acid, sulfuric acid and phosphoric acid, or salts of organic acids, such as methanesulfonic acid, p-toluenesulfonic acid, lactic acid, formic acid acetic acid, trifluoroacetic acid, citric acid, succinic acid, fumaric acid, maleic acid and salicylic acid. Further examples of pharmacologically acceptable salts of the compounds of formula (I) are alkali metal and alkaline earth metal salts such as, for example, sodium, potassium, lithium, calcium or magnesium salts, ammonium salts or salts of organic bases such as, for example, methylamine, dimethylamine , triethylamine , piperidine, ethylenediamine , lysine, choline hydroxide, meglumine, morpholine or arginine salts. Compounds of formula (I) may be solvated, especially hydrated. The hydration may take place, for example, during the preparation process or as a consequence of the hygroscopic nature of the
initially anhydrous compounds of formula (I) . The solvates and/or hydrates may e.g. be present in solid or liquid form.
The therapeutic use of compounds of formula (I), their pharmacologically acceptable salts, solvates and hydrates,
respectively, as well as formulations and pharmaceutical compositions also lie within the scope of the present
invention .
The pharmaceutical compositions according to the present invention comprise at least one compound of formula (I) as an active ingredient and, optionally, carrier substances and/or adj uvants .
The use of compounds of formula (I) for the preparation of medicaments for the treatment and/or prevention of cancer is also subject of the present invention. Moreover, the present compounds are of interest for the prevention and/or treatment of tumor diseases.
Cancers that can be treated or prevented by the compositions and methods of the present invention include, but are not limited to human sarcomas and carcinomas, e.g., fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma , lymphangiosarcoma , lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing 1 s tumour, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma, pancreatic cancer, breast cancer, ovarian cancer, prostate cancer, squamous cell carcinoma, basal cell carcinoma,
adenocarcinoma, sweat gland carcinoma, sebaceous gland
carcinoma, papillary carcinoma, papillary adenocarcinomas,
cystadenocarcinoma , medullary carcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma, bile duct
carcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilms1 tumour, cervical cancer, testicular tumour, lung carcinoma, small cell lung carcinoma, bladder carcinoma, epithelial carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma, meningioma, melanoma, neuroblastoma, retinoblastoma; leukemias, e.g., acute
lymphocytic leukaemia and acute myelocytic leukaemia
(myeloblastic, promyelocytic , myelomonocytic , monocytic and erythroleukemia) ; chronic leukaemia (chronic myelocytic
(granulocytic) leukaemia and chronic lymphocytic Leukaemia) , and polycythemia vera, lymphoma (Hodgkin's disease and non- Hodgkin's disease), multiple myeloma. Waldenstrohm ' s
macroglobulinemia, and heavy chain disease.
Other examples of leukaemias include acute and/or chronic leukaemias, e.g., lymphocytic leukaemia (e.g., as exemplified by the p388 (murine) cell line) , large granular lymphocytic leukaemia, and lymphoblastic leukaemia; T-cell leukaemias, e.g., T-cell leukaemia (e.g., as exemplified by the CEM, Jurkat, and HSB-2 (acute), YAC 1 (murine) cell lines), T- lymphocytic leukaemia, and T- lymphoblastic leukaemia; B cell leukaemia (e.g., as exemplified by the SB (acute) cellline) , and B- lymphocytic leukaemia; mixed cellieukaemias , e.g., B and T cellieukaemia and B and T lymphocytic leukaemia: myeloid leukaemias, e.g., granulocytic leukaemia, myelocytic leukaemia
(e.g., as exemplified by the HL-60 (promyelocyte) cell line), and myelogenous leukaemia (e.g., as exemplified by the K562
(chronic) cellline) ; neutrophilic leukaemia; eosinophilic leukaemia: monocytic leukaemia (e.g., as exemplified by the THP-1 (acute) cellline) ; myelomonocytic Leukaemia; Naegeli-
type myeloid leukaemia; and nonlymphocytic leukemia. Other examples of leukaemias are described in Chapter 60 of The Chemotherapy Sourcebook, Michael C. Perry Ed., Williams & Williams (1992) and Section 36 of Holland Frie Cancer Medicine 5th Ed., Bast et al . Eds., B.C. Decker Inc. (2000). The entire teachings of the preceding references are incorporated herein by reference.
In general, compounds of formula (I) can be given as a single treatment or as multiple treatments either alone or in
combination with an arbitrary therapeutic substance according to known and accepted modes or as a continuous treatment whereby the active principle can be embedded in a matrix such as e.g. an implantable hydrogel . Compositions according to the invention can be administered in one of the following ways: orally, including dragees, coated tablets, pills, semi-solids, soft or hard capsules, solutions, emulsions or suspensions; parenteral, including injectable solutions; rectal as
suppositories; by inhalation, including powder formulation or as a spray, transdermal or intranasal. For the production of such tablets, pills, semi solids, coated tabletts, dragees and hard gelatine capsules the therapeutically used product is mixed with pharmacologically inert, inorganic or organic carriers, e.g. with lactose, sucrose, glucose, gelatine, malt, silica gel, starch, or derivatives thereof, talkum, stearinic acid or its salts, dried skim milk and the like. For the production of soft capsules one may use carriers like
vegetable oils, petroleum, animal or synthetic oils, wax, fat, polyols. For the production of liquid solutions and syrups one may use carriers for example water, alcohols, aqueous saline, aqueous dextrose, polyole, glycerin, vegetable oils,
petroleum, animal or synthetic oils. For the production of
suppositories one may use excipients like e.g. vegetable, petroleum, animal or synthetic oils, wax, fat and polyols. For aerosol formulations one may use compressed gases suitable for this purpose like e.g. oxygen, nitrogen, noble gas and carbon dioxide. The pharmaceutically useful agents may also contain additives for conservation, stabilisation, e.g. UV stabilizer, emulsifier, sweetener, aromatiser, salts to change the osmotic pressure, buffers, coating additives and antioxidants.
Combinations with other therapeutic agents can include further agents, which are commonly used to treat the diseases
mentioned above, especially tumor diseases.
It has been surprisingly found that the compounds of the present invention wherein R' ' is -CH2OH show the same or a very similar biological activity as the known Tubulysins (see e.g. WO 9813375; F. Sasse, H. Steinmetz, G. H5fle, H. Reichenbach, J. Antibiot. 2000, 53, 879-885; A. W. Patterson et al , Chem. Eur. J. 2007, 13, 9534-9541), although the "Tup" unit has been replaced by a phenylalanine derivative, a much simpler
structural unit which is much less complicated to synthesize. The replacement of the "Tup" unit by a derivative of a natural amino acid makes the overall compounds more peptide- like which improves the biodegradability of the compounds in the body. Furthermore, this replacement leads to a reduction of the overall weight of the resulting compounds which leads to an enhanced bioavailability. In addition, the new compounds show an enhanced binding to tubulin.
Examples
According to the synthetic procedures of the building blocks disclosed herein, compounds of formula (I) were synthesized using common peptide coupling methods known to a person skilled in the art.
Compounds of formula (I) having the following residues where prepared :
R: H, methyl, propyl;
n: 0.
Synthetic Procedures
The syntheses of the respective carbonic acid derivatives of compounds MSRD334, MSRD345 and SDRD28 were performed according to procedures described in PCT/EP2008/003762 (WO 2008/138561) . All compounds described in this patent were characterized by 1H-NMR, 13C-NMR and mass spectroscopy. The purity was
identified by HPLC .
Synthesis of MSRD368:
MSRD356
To a solution of dipeptide (200mg, 0.44 mmol) in a 1:1 mixture of chloroform/formaldehyde dimethyl acetal (2 mL) P205 was added portionwise (626 mg, 4.4 mmol) . The reaction mixture was poured into a saturated aqueous solution of NaHC03 (25 mL) and extracted with AcOEt (1x10 mL) . The solvent was removed in vacuo and the crude product was purified by flash
chromatography (hexane :AcOEt 7:3) to give 154 mg of MSRD356 (70 % yield) as a colorless oil.
To a solution of MSRD356 (144 mg, 0.29 mmol) in a THF/H20 4:1 mixture (5 mL) , LiOH. H20 (19 mg, 0.43 mmol) was added. The reaction was stirred for 5 h, then H20 (10 mL) and AcOEt (10 mL) were added. The layers were separated and a 1 M solution of HC1 was added to the aqueous phase until pH 1-2 was
reached. The resulting mixture was extracted with AcOEt. The organic phase was dried over anhydrous Na
2S0
4, filtered and the solvent was removed in vacuo to give 119 mg of pure MSRD357 (87% yield) as a white solid.
To a solution of MSRD357 (109 mg, 0.23 mmol) in DMF (5 mL) , HOAt (38 mg, 0.28 mmol), HATU (105 mg, 0.28 mmol) and Et3N (70 μΐι, 0.51 mmol) were added. After stirring for 5 min Tup (55 mg, 0.25 mmol) was added. The reaction mixture was stirred for 2 h. The reaction was diluted with H20 (10 mL) and extracted with Et20 (1x10 mL) . The organic phase was washed with a IN aqueous solution of HC1 (1 x 15 mL) , with a saturated aqueous solution of NaHC03 (lx 15 mL) and with brine (2 x 15 mL) . After drying over anhydrous Na2S04, and filtration, the solvent was removed in vacuo to give 159 mg of pure MSRD360 (quantitative yield) as a white foam.
To a solution of MSRD360 (149 mg, 0.22 mmol) in MeOH (5 mL) , Pd/C was added. The reaction mixture was stirred 18 h under a hydrogen atmosphere. The reaction was filtered through celite and the filtrate was concentrated under reduced pressure to
give 142 mg of pure MSRD362 as white foam in quantitative yield .
To a suspension of N-Methylpipecolinic acid (34 mg, 0.24 mmol) in DCM (5 mL) , HOAt (35 mg, 0.26 mmol), HATU (99 mg, 0.26 mmol), Et3N (67 μΐΐ,, 0.48 mmol) and MSRD362 (142 mg, 0.22 mmol) were added. The reaction mixture was stirred for 4h. The reaction was washed with H20 (10 mL) , with a saturated aqueous solution of NaHC03 (lx 15 mL) and with brine (1 x 15 mL) . After drying over anhydrous Na2S04, and filtration, the solvent was removed in vacuo. The crude was purified by FC (DCM : MeOH 97:3) to give 107 mg of MSRD364 (63% yield) as a white foam.
To a solution of MSRD364 (102 mg, 0.13 mmol) in THF (5 mL) , a IN aqueous solution of LiOH (400 μL, 0.40 mmol) was added. The reaction was stirred for 2 days and then acidified with TFA
until pH 1-2 was reached. The resulting mixture was washed with H20 (5 mL) and extracted with AcOEt (10 mL) . The organic phase was basified with Et3N until pH 8 was reached, washed with H20 (5 mL) , dried over anhydrous Na2S04, filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography (DCM/MeOH 9:1), affording 52 mg of
MSRD365 (52 % yield) as a white foam. The reduction of MSRD365 towards MSRD368 was done according to the general procedure described below.
Synthesis of MSRD390:
MSRD371
To a solution of phenylalaninole 300 mg, 1.98 mmol) in DCM (10 mL) , cooled at 0°C, Et3N (414 μL, 2.97 mmol), imidazole (269 mg, 3.96 mmol) and TBDPCI (516 μL, 1.98 mmol) were added. The reaction mixture was warmed to r.t., stirred overnight and quenched with water (5 mL) . The layers were separated and the organic phase dried over anhydrous Na2S0 , filtered and the solvent was removed in vacuo. The residue was purified by flash chromatography (DCM/MeOH 97:3, DCM/MeOH 95:5), affording 647 mg of MSRD371 (84 % yield) as a colorless oil.
SRD379
To a solution of dipeptide (85 mg, 0.20 mmol) in DMF (5 mL) HOAt (33 mg, 0.24 mmol), HATU (91 mg, 0.24 mmol), Et3N (61 μΐ, 0.44 mmol) and MSRD371 (93 mg, 0.24mmol) were added. The reaction mixture was stirred for 4 h and 20 mL Et20 were added. The reaction was washed with H20 (10 mL) , with a saturated aqueous solution of NaHC03 (lx 15 mL) and with brine (1 x 15 mL) . After drying over anhydrous Na2S04, and filtration, the solvent was removed in vacuo to give 157 mg of pure MSRD379 (quantitative yield) as a white foam.
MSRD380
To a solution of MSRD379 (149 mg, 0.19 mmol) in DCM (10 mL) Ac20 (76 μL, 0.93 mmol), pyridine (45 μL, 0.47 mmol) and a catalytic amount of D AP were added. The reaction mixture was stirred for 3h and the solvent was removed in vacuo. The
residue was purified by flash chromatography (Hex/AcOEt 7:3) to give 143 mg of MSRD380 (89% yield) as a white foam. SRD388
To a solution of MSRD380 (133 mg, 0.16 mmol) in MeOH (5 mL) Pd/C was added. The reaction mixture was stirred 18 h under a hydrogen atmosphere. The reaction was filtered through celite and the filtrate was concentrated under reduced pressure to give 124 mg of pure MSRD388 (95% yield) as white foam.
MSRD389
To a suspension of N-Methylpipecolinic acid (33 mg, 0.23 mmol) in DCM (5 mL) HOAt (33 mg, 0.24 mmol), HATU (91 mg, 0.24 mmol), Et3N (54 μΙ_ι, 0.39 mmol) and MSRD388 (124 mg, 0.15 mmol) were added. The reaction mixture was stirred for 4h. The reaction was washed with H20 (10 mL) , with a saturated aqueous solution of NaHC03 (lx 15 mL) and with brine (1 x 15 mL) . After drying over anhydrous Na2S0 , and filtration, the solvent was removed in vacuo. The crude product was purified by flash
chromatography (DCM : MeOH 97:3) to give 100 mg of MSRD389 (71% yield) as a white foam.
MSRD390
To a solution of MSRD389 (89 mg, 0.09 mmol) in THF (3 mL) a 1M solution of Bu4NF in THF (189 μΐ.,, 0.189 mmol) was added. The reaction mixture was stirred for 4 min and washed with water (5 mL) . The aqueous phase was extracted with AcOEt (1X10 mL) . The collected organic phases were dried over anhydrous Na2S04, filtrated and the solvent was removed in vacuo. The crude product was purified by flash chromatography (DCM:MeOH 97:3, 93:7) to give 59 mg of MSRD390 (94% yield) as a white foam. All analytical data (HNMR, C MR, MS) correspond to the
structure of MSRD390.
General Procedure for the reduction of the carbonic acid derivatives MSRD334, MSRD345, MSRD368 and SDRD28:
To a solution of the corresponding carbonic acid derivative (0.04 mmol) in THF (2 mL) , Et3N (7 μL, 0.05 mmol) was added. After cooling the reaction mixture to 0°C, EtOCOCl (5 μL, 0.05 mmol) was added. The reaction was stirred at the same temperature for 30 min and filtered through celite. The solution was
then added to a solution of NaBH4 (3.0 mg, 0.08 mmol) in water (1 mL) and cooled at 0°C. The reaction mixture was stirred at the same temperature for 30 min, quenched with H20 (5 ml) and extracted with EtOAc (1x5 mL) . The solvent was removed in vacuo and the crude product was purified by flash chromatography (DC : MeOH 94:6) to give 24 mg of the corresponding alcohol (81 % yield) as a white foam.
Determination of the IC-50 Concentration against various cancer cell lines
The activity of some representative example compounds of the present invention has been determined with the BrdU-Assay as described in: Porstmann T. , Ternynck T., Avrameas S. (1985) "Quantification of 5-bromo-2-deoxyuridine incorporation into DNA: an enzyme immunoassay for the assessment of the lymphoid cell proliferative response." J. Immunol. Methods 82: 169-179.
The results are shown in Table 1.
Table 1
In general the new molecules of the present invention show an activity against several cancer cell lines between 0.1 to 400 nM.
Determination of the destabilisation effect against
microtubuli (Figure 1)
Figure 1 shows the destabilising effect against microtubuli. To proof that the novel compounds according to formula (I) are showing an destabilizing effect against microtubuli the in vitro activity was measured in an tubulin polymerisation assay. As controls a tubulin stabilising agent (taxol) and strong destabilising agents (vinblastin and tubulysin A) were used. The novel compounds show an remarkable destabilising effect against microtubuli like e.g. vinblastin.
Determination of the concentration dependency of the
microtubuli polymerisation
Figures 2a-e show the concentration dependency in the
microtubuli polymerisation assay. A clear concentration dependent effect against microtubuli polymerisation was determined .
Determination of the in-vitro activity in the tubulin
polymerisation assay
Figures 3a-b shows the IC-50 concentration against tubulin polymerisation. The IC-50 concentration of the activity against the tubulin polymerisation was determined and compared to strong inhibitors of the micrtubuli skeleton like e.g.
vinblastin, tubulysin A.