Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/5005—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells
  • G01N33/5008—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells for testing or evaluating the effect of chemical or biological compounds, e.g. drugs, cosmetics
  • G01N33/5011—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells for testing or evaluating the effect of chemical or biological compounds, e.g. drugs, cosmetics for testing antineoplastic activity
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
  • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
  • C12Q1/34—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving hydrolase
  • C12Q1/42—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions involving hydrolase involving phosphatase
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y5/00—Nanobiotechnology or nanomedicine, e.g. protein engineering or drug delivery

Definitions

• the present invention relates to a method of detecting cancer and, more particularly, to methods of optimizing drug treatment for cancer.
• Cancer is responsible for the majority of morbidity and mortality worldwide, despite recent advances in medical technology.
• Current therapeutic strategies focus predominantly on achieving the removal or death of cancer cells within the patient, through a diverse array of surgical and non- surgical techniques; the most widely used are chemotherapy and gamma irradiation.
• Those methods have a number of prominent disadvantages, in particular the culling of healthy cells/tissues within the patient, and the rather toxic side-effects of the current generation of chemotherapeutic drugs utilized in cancer treatment.
• Differentiation therapy is an alternative approach which promotes reversion of phenotype from malignant to normal.
• Differentiation therapy is based on the concept that cancer cells are normal cells that have been arrested at an immature or less differentiated state, lack the ability to control their own growth, and thus multiply at an abnormally fast rate.
• Differentiation therapy aims to force the cancer cell to resume the process of maturation. Although differentiation therapy does not kill the cancer cells, it restrains their growth and allows the application of more conventional therapies (such as chemotherapy) to eradicate the remaining malignant ceils.
• Differentiation therapy has a number of advantages over conventional therapeutic strategies that target death of cancer/tumor cells.
• the culling of healthy cells/tissues within the patient with chemotherapeutic drugs or gamma irradiation would be eliminated, together with their associated adverse side-effects.
• the killing of cancer cells through gamma irradiation or chemotherapeutic eliminates most, but not completely all cancer cells within the patient, thereby leading to remission of the disease.
• differentiation therapy it is speculated that by inducing some of the cancer cells into the pathway of terminal differentiation and eventual senescence, this would somehow signal other cancer cells to follow suit through a variety of mechanisms.
• Various markers have been used as a means of monitoring patients undergoing differentiation therapy.
• alkaline phosphatase is alkaline phosphatase, wherein expression of same was shown to correlate with the differentiation status of a cell [Patnaik A, et al., Clin. Can Research, 2002 Jul;8(7):2142-8; Rephaeli A, Zhuk R, Nudelman A, 2000, Drug Develop. Res. VoI 50:379- 391], Rapid and easy detection of such markers with high sensitivity, selectivity and accuracy paves the way for tailoring therapeutic agent to specific patients - 'personalized medicine'. This is of great importance in cancer therapy where it is now known that tumor treatment response cannot be predicted only from its type and anatomical location.
• U.S. Pat. App. No. 20060100488 teaches detection of cancerous cells by directly monitoring the electrical response of the cells following application of an alternating current.
• WO 91/15595 teaches analysis of electrical conductivity of cancer cells for monitoring responsiveness to therapy and drug screening. Specifically, WO 91/15595 teaches monitoring the effectiveness of a particular agent to inhibit increases in the volume and number of cancer cells by analyzing electrical conductivity thereof. Accordingly, both these patent applications teach that the intrinsic electrical properties of a cancer cell may be used as markers for detection and monitoring of cancer cells.
• U.S. Pat. Appl. No. 20040053425 teaches amperometric analysis of an analyte in a fluid, wherein the electrode comprises the current producing enzyme.
• U.S. Pat. Appl No. 20040053425 does not teach amperometric detection of intracellular markers.
• U.S. Pat. No. 5,149,629 teaches amperometric analysis of markers, including cancer cell markers, wherein the electrode comprises antibodies capable of binding the markers thereto. The analysis is by substrate competition. U.S. Pat. No. 5,149,629 does not detect endogenous amperometric features of cancer cells.
• amperometric detection of analytes has been shown to be an effective method for detection. However, until presently, amperometric detection has not been used for analyzing cellular enzymatic activities.
• a method of detecting a cancer cell comprising: (a) contacting the cell with a substrate for an enzyme under conditions wherein the enzyme catalyzes a reaction of the cell with the substrate, so as to generate a product capable of producing an electrical signal; and (b) measuring a level of the electrical signal, wherein a difference in a level of the electrical signal compared to a predetermined threshold is indicative of a cancer cell.
• a method of diagnosing a subject with cancer comprising: (a) contacting at least one cell in a sample of a subject with a substrate for an enzyme under conditions wherein the enzyme catalyzes a reaction of the cell with the substrate, so as to generate a product capable of producing an electrical signal; and (b) measuring a level of the electrical signal, wherein a difference in a level of the electrical signal compared to a predetermined threshold is indicative of cancer.
• a method of individually optimizing a treatment for cancer comprising: (a) contacting at least one cancer cell in a sample of a subject with at least one anti cancer agent; (b) contacting the at least one cancer cell with a substrate for an enzyme, under conditions wherein the enzyme catalyzes a reaction of the cell with the substrate, so as to generate a product capable of producing an electrical signal; and (c) measuring a level of the electrical signal produced by the cell, wherein the level is indicative of an efficiency of the anti cancer agent to treat the cancer of the subject.
• a method of monitoring an anti cancer treatment in a subject comprising:(a) administering at least one anti cancer agent to the subject; (b) detecting a presence or level of cancer cells in a sample of the subject following step (a) according to the method of the present invention, wherein the presence or level is indicative of a state of the cancer.
• a method of determining an anti-cancer treatment for a subject comprising: (a) analyzing a presence or level of cancer cells in a sample of the subject according to the method of the present invention; (b) administering to the subject a therapeutic effective amount of an anti cancer agent according to the presence or level of cancer cells in the sample of the subject.
• the method further comprises repeating step (a) following step (b).
• a method of identifying an agent capable of reversing a malignant phenotype of a cell comprising, (a) subjecting at least one cancer cell to an agent; (b) measuring a malignant phenotype of the cell following (a) and optionally prior to (a) according to the method of the present invention, wherein a reversion of phenotype is indicative of an agent capable of reversing a malignant phenotype of a cell.
• kits comprising:(i) at least one component of an electrochemical cell, the electrochemical cell being adapted for holding at least one biological cell and for performing electrochemical measurement; and (ii) at least one anti-cancer agent.
• the kit further comprises a substrate which is enzymatically reacted on by an enzyme of the biological cell to yield a reaction product giving rise to a redox reaction at an electrode of the electrochemical cell.
• a system configured for detecting a cancer cell according to the method of the present invention.
• the at least one cell comprises a plurality of cells.
• the measuring is performed using means for high output.
• the means is selected from the group consisting of an automated sampling device, a liquid handling equipment, a dispenser, an electrode array, a robot, or any combination thereof.
• the contacting is effected in vitro.
• the contacting is effected ex vivo.
• the sample comprises no more than 500 cells. According to still further features in the described preferred embodiments, the biopsy sample comprises no less than 10 cells.
• the enzyme is alkaline phosphatase.
• the substrate is p-APP.
• the cancer cells are colon cancer cells.
• the measuring is effected using an electrochemical cell.
• the measuring is effected in a multiwell array.
• each well of the multiwell array comprises an electrochemical cell.
• each well of the multiwell array is a nano-volume well.
• the agent comprises a test composition.
• the test composition is selected from the group consisting of a polynucleotide a polypeptide, a small molecule chemical, a carbohydrate, a lipid and a combination of same.
• the agent comprises a test condition.
• the test condition is a radiation condition.
• the cell is intact.
• the cancer cells are intact.
• the cell is a mammalian cell.
• the cancer cells are mammalian cells.
• FIGS. 1A-C are graphs depicting the HT-29 colon cancer cell response to BA, butyroylmethyl-diethyl phosphate and pivaloyloxymethyl butyrate. Amperometric response curves for monitoring of alkaline phosphatase activity were generated using the electrochemical array chip.
• the HT-29 colon cancer cells were exposed to the following differentiation agents: Butyric acid (2.5 mM) - Figure 1A, butyroylmethyl-diethyl phosphate and pivaloyloxymethyl butyrate (50 ⁇ M) - Figures 1 B and 1C respectively.
• the HT-29 cells with the substrate PAPP were placed into the 10OnL volume electrochemical chambers on the chip. Current was measured using the amperometric technique at 22OmV. Error estimation (5 repeats) is 2nA RMS.
• FIGs. 2A-C are photographs illustrating the number of cells per sample.
• FIGs. 2D-F are graphs illustrating the enzymatic activities of the samples versus cell numbers. Error estimation (5 repeats) is 3 ⁇ A RMS.
• FIG. 3 is a bar graph depicting the correlation between HT-29 colon cancer cell number and the induced alkaline phosphatase enzymatic activity. Activity is presented by _current/_time. Each result represents the mean of three measurements. Current was measured using the amperometric technique at 22OmV.
• FlGs. 4A-C are graphs illustrating the effect of an eight hour treatment of butyroylmethyl- diethyl phosphate on HT-29 cells.
• Figure 4A is a bar graph illustrating the slope of alkaline phosphatase current signal.
• Figures 4B-C are graphs illustrating the change in current over time, on different numbers of treated ( Figure 4B) and non-treated ( Figure 4C) cells.
• FIGs. 5A-C are graphs illustrating the effect of a seventy eight hour treatment of butyroylmethyl-diethyl phosphate on HT-29 cells.
• Figure 5A is a bar graph illustrating the slope of alkaline phosphatase current signal.
• Figures 5B-C are graphs illustrating the change in current over time, on different numbers of treated ( Figure 5B) and non-treated ( Figure 5C) cells.
• FIGs. 6A-C are graphs illustrating the effect of a ninety six hour treatment of butyroylmethyl-diethyl phosphate on HT-29 cells.
• Figure 6A is a bar graph illustrating the slope of alkaline phosphatase current signal.
• Figures 6B-C are graphs illustrating the change in current over time, on different numbers of treated ( Figure 6B) and non-treated ( Figure 6C) cells.
• the present invention is of a method of detecting cancer cells. Specifically, the present invention can be used to diagnose cancer, monitor treatment, determine treatment regimens and develop novel treatment modalities for the disease.
• Differentiation therapy focuses on the induction of cancer cells to normal cells by forcing the cancer cells to resume a process of maturation.
• Numerous markers have been used as a means of monitoring patients undergoing differentiation therapy.
• One such marker Js alkaline phosphatase, wherein expression of same was shown to correlate with the differentiation status of a cell.
• normal enzymatic activity denotes that the cells differentiate properly as a consequence of the particular drug treatment, whilst lack of enzymatic activity denotes ineffectual drug treatment for the particular cancer and/or for the particular patient.
• the present inventors have developed a novel electrochemical method for sensitive and high-throughput detection of a cancer cell's response to differentiation therapy.
• Utilizing nano-volume analytical device is of special interest in clinically relevant samples since it requires less tissue for diagnostics, and enables high-throughput analysis and comparison of the effect of various drugs on one tumor sample, while keeping uniform biological and environmental conditions.
• this new method can help tailor cancer drugs and treatments to individual patients towards 'personalized medicine 1 .
• a method of detecting a cancer cell comprises contacting the cell with a substrate for an enzyme, under conditions wherein the enzyme catalyzes a reaction of the cell with the substrate, so as to generate a product capable of producing an electrical signal and subsequently, measuring a level of the electrical signal, wherein a difference in a level of the electrical signal compared to a predetermined threshold is indicative of a cancer cell.
• detecting refers to the act of detecting, diagnosing, perceiving, uncovering, exposing, visualizing or identifying a cell.
• the term "cell” refers to a mammalian cell, preferably a human cell.
• Single cells may be used in accordance with the teachings of the present invention as well as plurality of cells.
• the plurality of cells comprises no less than 10 cells and no more than 500 cells.
• the cells are in a single suspension such that the number of cells may be counted, although adherent cells and aggregates may still be detected.
• the plurality of cells may be from any biological sample such as cell-lines, primary cultures and cellular samples, e.g. biopsies (surgical biopsies including incisional or excisional biopsy, fine needle aspirates and the like), complete resections or body fluids. Methods of biopsy retrieval are well known in the art.
• the cells in the biological sample may be assayed for a functional enzyme without any pretreatment.
• the cells in the biological sample are preferably intact (i.e. whole), and preferably viable, although it will be appreciated that pre-treatment of cells, such as generation of cell extracts or non-intact cells are also contemplated by the present invention.
• a “cancer cell”, also referred to herein as a “malignant cell”, is a cell which has been released from normal cell division control, and is thus characterized by an abnormal growth and a tendency to proliferate in an uncontrolled way and, in some cases, to metastasize.
• the cancer cell may be a neoplastic cell, a pre-malignant cell, a metastatic cell, a tumor cell, an oncogenic cell, a cell with a cancer genotype, a cell of malignant phenotype, an oncogene transfected cell, a virus transformed cell, a cell which expresses an oncogene, a cell which expresses a marker for cancer, or a combination thereof.
• Non-limiting examples of a cancer cell which may be detected by the method of the present invention is: an adenocarcinoma cell, an adrenal gland tumor cell, an ameloblastoma cell, an anaplastic cell, anaplastic carcinoma of the thyroid cell, an angiofibroma cell, an angioma cell, an angiosarcoma cell, an apudoma cell, an argentaffmoma cell, an arrhenoblastoma cell, an ascites tumor cell, an ascitic tumor cell, an astroblastoma cell, an astrocytoma cell, an ataxia- telangiectasia cell, an atrial myxoma cell, a basal cell carcinoma cell, a benign tumor cell, a bone cancer cell, a bone tumor cell, a brainstem glioma cell, a brain tumor cell, a breast cancer cell, a Burkitt's lymphoma cell, a cancerous cell, a carcinoid cell,
• a melanoma cell a meningioma cell, a mesothelioma cell, a metastatic cell, a metastasis cell, a metastatic spread cell, a Morton's neuroma cell, a multiple myeloma cell, a myeloblastoma cell, a myeloid leukemia cell, a myelolipoma cell, a myeloma cell, a myoblastoma cell, a myxoma cell, a nasopharyngeal carcinoma cell, a neoplastic cell, a nephroblastoma cell, a neuroblastoma cell, a neurofibroma cell, a neurofibromatosis cell, a neurogliorna cell, a neuroma cell, a non-Hodgkin's lymphoma cell, an oligodendroglioma cell, an optic glioma cell, an osteochond
• the cancer cell is a colon cancer cell.
• the method of the present invention is effected by contacting an enzyme substrate with a cell, to bring about a reaction of the cell, wherein the product of the enzymatic reaction is capable of generating an electrical signal.
• reaction of the cell refers to a reaction that occurs between the substrate and an endogenous enzyme expressed by the cell, and not to a reaction that occurs with an exogenous enzyme.
• the substrate is selected according to the enzyme, (also referred to herein as "marker enzyme") that is required to be detected.
• the enzyme may be situated inside the cell (i.e. intracellular) or on the cell membrane (i.e. membrane bound).
• the enzyme is a secreted enzyme.
• the substrate is preferably membrane permeable.
• the substrate is preferably selected such that following catalysis, the product formed is also membrane permeable such that it may diffuse away from the cell and on to the detector electrode
• the enzyme required to be detected is alkaline phosphatase (or enzyme secreted alkaline phosphatase, (SEAP)) and the substrate is 17, 4-aminophenyl phosphate (p-APP).
• Alkaline phosphatase converts p-APP to the electrochemical product, p- aminophenol (PAP).
• P-APP is widely commercially available from such Companies as Sigma-Aldrich
• Alkaline phosphatase is present in normal cells, but is reduced (or even absent) in cancerous cells. Therefore, analysis of the alkaline phosphatase activity level of cells, may be used as a marker for evaluating the efficiency of a particular drug for treating cancer and even for diagnostic purposes.
• the term "contacting" refers to bringing the substrate into the vicinity of a cell under conditions such that the substrate may be catalyzed by the enzyme.
• the contacting should by effected under buffer conditions, at a temperature and time sufficient to allow catalysis of the substrate and generation of sufficient product that it may be detected by an electrochemical cell.
• the contacting is effected for at least 5 minutes, at room temperature - see Examples 2 and 3 herein below.
• the contacting may be effected in vitro, ex vivo or in vivo.
• the contacting may be effected in a vessel which is also capable of detecting the product of the enzymatic reaction (i.e., in the electrochemical cell), such that the electrical signal is detected on-line.
• the contacting may be effected in a separate vessel from where the detection takes place such that it is possible to continuously withdraw samples at particular time points and place such samples within the electrochemical cells.
• the contacting may be effected in a test tube, flask, tissue culture, chip, array, plate, microplate, capillary, or the like.
• the cells may be placed on a vibrating plate following the addition of the substrate for continuous thorough mixing of the contents of the cells.
• electrochemical measurement of products capable of undergoing a redox reaction (i.e. capable of electron transfer) at an electrode of a chemical cell to yield an electrical signal is typically effected in electrochemical cells.
• electrical signal refers to electrons or electrochemically active species.
• electrochemical measurement refers to a measurement performed by the use of electrodes in a solution, typically in an electrochemical cell. The measurement may be performed, for example, by chrono-amperometry, chrono-potentiometry, cyclic voltammetry, chrono-coulometry or square wave voltammetry. A signal detectable in such a measurement, is one that differs in such electrochemical measurement from the control.
• the electrochemical cells of the present invention comprise a measurement electrode, a return electrode, a reference electrode and a chamber to hold the cells.
• the working electrode may be of a variety of different kinds, for example, it may be made of carbon, including glassy carbon, activated carbon cloth electrode, carbon felt, platinized carbon cloth, plain carbon cloth), may be made of gold, platinum or silver.
• the counter electrode may also be made of the same material as the working electrode.
• the reference electrode may for example be saturated calomel electrode, may be an Ag/AgCI electrode.
• the electrodes may be of a screen printed electrode which can be inserted into the vessel comprising the cells without the need to withdraw a sample and transport it into a separate electrochemical cell.
• the electrodes used to detect the product according to the method of the present invention may be reusable electrodes or disposable ones.
• Reusable electrodes may for example be electrodes made of glassy carbon in a disk or rod shape which are embedded in teflon. Disposable electrodes may for-example be electrodes in the form of carbon paper, carbon cloth, carbon felts, or the screen printed electrode of the kind noted above.
• the electrochemical cell is a three-electrode cell.
• the electrochemical cell is a two-electrode cell.
• the electrochemical cells are provided as an array (i.e. chip) comprising a plurality of such cells i.e. a multiwell array where each well is of a nano-volume size.
• the system for measuring the electrical signal generated by the reaction product may further comprise a control module which may be a computer, a potentiostat and a multiplexer module which is needed in case of a typical embodiment for simultaneous measurement from a plurality of electrochemical cells.
• a control module which may be a computer, a potentiostat and a multiplexer module which is needed in case of a typical embodiment for simultaneous measurement from a plurality of electrochemical cells.
• the computer scans all the electrodes via the parallel port, and the background response to the potential application of each electrode is recorded by the computer.
• the entire electrochemical measurement sequence can be performed over a long period of time while measuring the currents resulting from the changes in the concentration of the products.
• the system can be calibrated by measuring the oxidation or reduction of an electroactive species, typically the same species which is the product of the enzymatic reaction in the electrochemical cell and comparison of the results of all the electrodes.
• the electrodes may be connected to the potentiostat and at the same time also collected via the multiplexer to a parallel port of the microcomputer.
• Each electrode is inserted in an electrochemical cell containing a reference electrode and a counter electrode which are also connected to the potentiostat.
• a specific potential is applied by the potentiostat on the electrodes (which can be the same for all the electrodes or can be a different potential to each electrode) and the current in each electrode is detected.
• the electrical signals are visualized in real-time on the computer screen.
• the signals generated by the electrochemical products of the enzymatic reactions reflect the level of enzyme in the cell, and the enzymes (presence, absence or level of same) are markers for cancer
• the signals may be used to determine whether a cell is cancerous (i.e. malignant) or not. Specifically, if the level of the generated electrical signal is different to a predetermined threshold, this would indicate that the cell is cancerous.
• the predetermined threshold is determined by the electrical signal generated by a control cell.
• the control cell can be a normally differentiated cell, non-cancerous cell, preferably of the same tissue and specimen as the tested cell suspicious of a cancerous or undifferentiated phenotype.
• the difference is at least 10 %, 20 %, 30 %, 40 %, 50 %, 80 %, 100 % (i.e., two-fold), 3 fold, 5 fold or 10 fold different as compared to a control cell.
• the amount of enzyme (and accordingly electrical signal) in a cancer cell is lower than the amount of enzyme (and accordingly electrical signal) in a non-cancer cell.
• the amount of enzyme (and accordingly electrical signal) in a cancer cell is higher than the amount of enzyme (and accordingly electrical signal) in a non-cancer cell.
• the method of the present invention may be used for diagnosing a subject with cancer.
• diagnosis refers to classifying a cancer, determining a severity of cancer (grade or stage), monitoring cancer progression, forecasting an outcome of the cancer and/or prospects of recovery.
• the subject may be a healthy animal or human subject undergoing a routine well-being check up.
• the subject may be at risk of having cancer (e.g., a genetically predisposed subject, a subject with medical and/or family history of cancer, a subject who has been exposed to carcinogens, occupational hazard, environmental hazard] and/or a subject who exhibits suspicious clinical signs of cancer [e.g., blood in the stool or melena, unexplained pain, sweating, unexplained fever, unexplained loss of weight up to anorexia, changes in bowel habits (constipation and/or diarrhea), tenesmus (sense of incomplete defecation, for rectal cancer specifically), anemia and/or general weakness).
• cancer e.g., a genetically predisposed subject, a subject with medical and/or family history of cancer, a subject who has been exposed to carcinogens, occupational hazard, environmental hazard
• a subject who exhibits suspicious clinical signs of cancer
• the present has a variety of applications pertaining to individually optimizing a treatment for cancer, monitoring an-anti cancer treatment in a subject, determining an anti cancer treatment for a subject and identifying an agent capable of reversing a malignant phenotype of a cell.
• a method of identifying an agent capable of reversing a malignant phenotype of a cell comprises subjecting at least one cancer cell to an agent and determining the efficiency of the anti cancer agent by monitoring the activity or expression of the marker enzyme (e.g. alkaline phosphatase) according to the method of the present invention.
• the marker enzyme e.g. alkaline phosphatase
• reversing a malignant phenotype refers to at least partially reversing the proliferative and/or invasive characteristics of the malignant cell.
• agent refers to a test composition comprising a biological agent or a chemical agent
• biological agents examples include, but are not limited to, nucleic acids, e.g., polynucleotides, ribozymes, siRNA and antisense molecules (including without limitation RNA, DNA, RNA/DNA hybrids, peptide nucleic acids, and polynucleotide analogs having altered backbone and/or bass structures or other chemical modifications); proteins, polypeptides (e.g. peptides), carbohydrates, lipids and "small molecule" drug candidates.
• nucleic acids e.g., polynucleotides, ribozymes, siRNA and antisense molecules (including without limitation RNA, DNA, RNA/DNA hybrids, peptide nucleic acids, and polynucleotide analogs having altered backbone and/or bass structures or other chemical modifications)
• proteins polypeptides (e.g. peptides)
• carbohydrates e.g. lipids and "small molecule" drug candidates.
• Small molecules can be, for example, naturally occurring compounds (e.g., compounds derived from plant extracts, microbial broths, and the like) or synthetic organic or organometallic compounds having molecular weights of less than about 10,000 daltons, preferably less than about 5,000 daltons, and most preferably less than about 1 ,500 daltons.
• the agents are differentiation agents including, but not limited to butyric acid and its derivatives.
• conditions that may be tested as potential anti cancer agents according to the method of the present invention include, but are not limited to, radiation exposure (such as, gamma radiation, UV radiation, X-radiation).
• the "marker enzyme" is also assayed prior to contact with the agent so that a comparison may be made prior to and following treatment.
• the agent is subjected to the cancer cells for a period long enough to have an anti cancer effect.
• these agents are subjected to the cancer cells for at least 1 day and more preferably 3 days.
• the agent may be contacted with cancer cells either in vitro, ex vivo or in vivo. If the contacting is effected in vivo, the cells are typically removed from the subject prior to contact with the substrate of the present invention.
• the present invention can, in theory, be practiced with a single electrochemical cell, such a method is not efficient nor is it desirable.
• the method of the present invention is used for high throughput screening of agents using a plurality of electrochemical cells to simultaneously screen a variety of agents.
• the cells may be part of a chip, for example a silicon chip as described in Example 1 herein below.
• the method of the present invention is performed using means for high output. Accordingly, the method may be performed, for example, using an automated sampling device, a liquid handling equipment, a dispenser, an electrode array, a robot, or any combination thereof.
• tumor treatment response cannot be predicted only from its type and anatomical location. It will be appreciated that the method of identifying an agent capable of reversing a malignant phenotype of a ceil may be modified such that particular patient's cells may be used in the assay system, thereby tailoring therapeutic agents to specific patients. Furthermore, it will be appreciated that not only may the specific agent be selected using the method of the present invention, but the optimal dose and optimal treatment regimen may also be identified according to the method of the present invention. In this way a therapeutically effective amount of an agent may be determined. The patient may be treated according to the optimal treatment conditions selected with the aid of the method of the present invention and optionally retested after a suitable time period. In this way a patient's response may be continually monitored whilst undergoing therapy.
• the analyzing enzyme levels and administering steps may be repeated a number of times during the course of a treatment.
• the alkaline phosphatase levels may be analyzed one week following administration of the agent. If the alkaline phosphatase levels are higher than those compared with a control, the dose of the agent may be decreased. If the alkaline phosphatase levels remain lower than those compared with a control, the dose of the agent may be increased.
• the electrochemical cell of the present invention may be provided in a kit together with at least one anti-cancer agent (e.g. a differentiation agent such as butyric acid) for determining an effect thereof on a cancer cell.
• the kit of the present invention may, if desired, be presented in a pack which may contain one or more units of the kit of the present invention.
• the pack may be accompanied by instructions for using the kit and the estimated dose of the anticancer agent for a particular number of cells.
• the pack may also be accommodated by a notice associated with the container in a form prescribed by a governmental agency regulating the manufacture, use or sale of laboratory supplements, which notice is reflective of approval by the agency of the form of the compositions.
• the kit may also comprise a substrate which is enzymatically reacted on by the marker enzyme of the biological cell (i.e. cancer cell) to yield a reaction product giving rise to a redox reaction at an electrode of the electrochemical cell.
• a substrate which is enzymatically reacted on by the marker enzyme of the biological cell (i.e. cancer cell) to yield a reaction product giving rise to a redox reaction at an electrode of the electrochemical cell.
• a nano-bio-chip was designed and fabricated using standard micro-system-technology (MST) methods. Its architecture included an array of miniaturized electrochemical cells. The cells were placed in the nano-volume chambers (i.e. the electrochemical-cells). The cylindrical chambers held 100 nl_ volume each. All arrays included positive and negative controls chambers.
• MST micro-system-technology
• the device was manufactured in two parts: a) a disposable chip - with the nano-chambers where the cells were placed, and b) a reusable chip, with an interface to electronic circuitry which included a multiplexer, potentiostat, temperature control and a pocket PC for sensing and data analysis. This setting allowed continuous reusing for multiple measurements.
• the chip was produced from silicon, and contained an array of eight miniaturized electrochemical cells. Each electrochemical-cell consisted of three circular-shaped electrodes, surrounded by an insulating silicon nitride layer: 1) Gold working electrode, 2) Gold counter electrode and 3) Ag/AgCI reference electrode. The electrodes were made by gold sputtering, microlithography and by selectively depositing Ag and anodizing it in a chloride containing solution for the reference electrode. The chambers walls were constructed from photopolymerized polyimide (SU-8) ( Figures 1A-B). The silicon chip was wire bonded to a plastic chip, which was interfacing the electronic circuit.
• SU-8 photopolymerized polyimide
• the signal sensing was performed by the handheld palm-potentiostat with an interface to electronic circuitry for electrode signal regulation and detection (Palm Instruments BV-2004).
• the electronics consisted of eight independent duplicate circuits of electrochemical cells, which are temperature-controlled. A potential was applied between a working and a reference electrode in each electrochemical cell, and the output current was measured.
• HT-29 human colon cancer cells were grown in DMEM medium in the presence of fetal bovine serum at 37 0 C in 95 % air, 5 % CO2 for 3 days prior to butyrate treatment. Butyrate at different concentrations was added to the HT-29 cell cultures. Concentrations applied were: 0, 0.078, 0.156, 0.3125, 0.625, 1.25, 2.5, 5 and 10 mM. Optimal butyrate concentration, LC50 and viability were calculated accordingly. The measurements were performed in PBS with the intact cells and without additional treatment of the cancer cells such as lysis.
• Butyric acid (BA) and its derivatives BA (Sigma, Israel) ranging between 0.08-10 mM were introduced to HT-29 colon cancer cells and incubated for 72 h for optimization. BA at a constant concentration of 2.5 mM was applied in all electrochemical experiments. BA derivatives, butyroylmethyl-diethyl phosphate, and pivaloyloxymethyl butyrate, were synthesized as described [Rephaeli A, Zhuk R, Nudelman A, 2000, Drug Develop. Res.Vol 50:379-391].
• Butyroylmethyl- diethyl phosphate was solubilized in PBS and pivaloyloxymethyl butyrate in DMSO followed by dilution with medium to a final DMSO concentration of ⁇ 0.1%.
• the prodrugs were then introduced to the cells at a constant concentration of 50 ⁇ M and incubated for 96 h at 37 0 C in 95 % air, 5 % CO2 conditions. Following incubation with the differentiation agents, viable cells were counted by tripa blue exclusion and tested for viability and LC 50 calculations. Prior to all electrochemical measurement, cells were centrifuged and diluted in PBS. All measurements were performed in PBS. The influence of BA 1 pivaloyloxymethyl butyrate and butyroylmethyl-diethyl phosphate were examined by measuring the enzymatic activity of alkaline phosphatase. Alkaline phosphatase activity measurements:
• Optical measurements Alkaline phosphatase activity was detected with the optical substrate para-Nitrophenyl Phosphate (PNPP kit ready to use, Sigma). The resultant enzymatic product was measured at wavelength of 420nm.
• Electrochemical measurements Amperometric enzyme measurements were performed with the electrochemical substrate, p-APP.
• the enzymatic reaction product, aminophenol (p-AP) is oxidized at the gold working electrode at 22OmV and the generated current was measured.
• Eight- channeled 100 nl_ volume electrochemical chambers were loaded with HT-29 cancer cells, that were treated with BA or its derivatives. Cells were placed into the electrochemical chambers and the substrate was added to 1 mg/ml final concentration at a total volume of 100 nL. The generated current was measured and the number of cells was counted under the microscope. The correlation between cell number and current density was analyzed.
• HT-29 human colon cancer cells
• RESULTS HT-29 colon cancer cells were exposed for 96 hours to various differentiation therapy agents and the induced alkaline phosphatase activity was measured.
• Each electrochemical chamber on the array was loaded with cells exposed to a different agent - namely Butyric acid, butyroylmethyl-diethyl phosphate and pivaloyloxymethyl butyrate.
• Figure 1A-C Normal enzymatic activity denotes that the cells differentiate properly as a consequence of the particular drug treatment.
• the ability to quantitate the enzymatic reaction is due to the miniaturized design of the chip, combined with the advantages of the electrochemical detection method.

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