Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K49/00—Preparations for testing in vivo
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
  • G01N1/30—Staining; Impregnating ; Fixation; Dehydration; Multistep processes for preparing samples of tissue, cell or nucleic acid material and the like for analysis
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K49/00—Preparations for testing in vivo
  • A61K49/001—Preparation for luminescence or biological staining
  • A61K49/006—Biological staining of tissues in vivo, e.g. methylene blue or toluidine blue O administered in the buccal area to detect epithelial cancer cells, dyes used for delineating tissues during surgery
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents

Definitions

• This invention relates to methods for detecting epithelial cancer.
• the invention pertains to methods for selectively killing epithelial cancer cells.
• the invention concerns methods for detecting epithelial cancer cells in the presence of normal cells and/or for selectively killing such cells, in which the mitochondria of cancer cells retain a mitochondrial marking agent for a time sufficient to permit identification and/or killing such cells.
• Cancer or “cancerous” cells are used in the broad sense, to include invasive cancer cells, cancer-in- situ cells and severely dysplastic cells.
• Mitochondrial marking agent means a compound that is selectively taken up by the mitochondria of living cancer cells and is selectively retained in cancer cells for a time sufficient to permit identification and/or killing or incapacitation thereof .
• “Killing" of cells means either causing cell death s apoptosis or cell changes that render a cell incapable of reproduction and metastasizing .
• Adduct means the reaction product, either covalent or noncovalent, of a mitochondrial marking agent and a cancer chemotherapeutic agent .
• Adjuvant means a mitochondrial marking agent that, in combination with another chemotherapeutic agent, causes improved killing of cancer cells, either synergistically or by additive effects with the other agent.
• In-vivo diagnostic procedures for detecting malignant and premalignant epithelial lesions or carcinomas employing dye compositions that selectively "color" tissues that are abnormal due to dysplasia, hyperplasia, tumorigenesis and other active surface lesions, are known in the art. These diagnostic methods employ a dye that imparts color to a cancerous substrate, which is then detectable under light at visible wavelengths or a fluorescent dye that imparts color to the substrate, which is then detectable when illuminated by light at wavelengths outside the visible spectrum.
• toluidine blue selectively marks cancerous epithelial tissue because it is selectively retained in the relatively larger interstitial spaces between cancer cells
• the mechanism of such selective staining of epithelial tissue by cationic dyes e.g., dyes such as rhodamine, fluoresceins, oxazine and thiazine dyes (including toluidine blue) and other cationic supravital marking agents, is the selective uptake and selective retention of the agent in the mitochondria of cancer cells.
• This selective mitochondrial uptake and retention is apparently due to the higher electrical potential (negative charge on the inside of the membrane) of cancerous cells' mitochondria as compared to mitochondria of normal cells. See, e.g., Chen et al .
• the selective marking of cancer cells by, and retention in the mitochondria of cancer cells of, supravital cationic dyes and other supravital cationic marking agents are related to one of the very characteristics of cancer cells that appears to be responsible for their rapid cloning growth and metastasizing ability, namely, that the higher electrical potential of the mitochondria of cancer cells is the source of cellular energy and is the driving force for ATP (adenosine triphosphate) production by the cells.
• Our detection methods comprise the steps of delivering a cationic supravital mitochondrial marking agent to tissue in the locus of a suspect cancerous site on the epithelium (which contains both normal and cancerous cells) , thus causing said agent to be taken up and selectively retained in the mitochondria of the cancer cells.
• the cancerous cells are then detectable by any suitable method, for example, instrumental or visual examination under visible light or under light of selected invisible wavelengths.
• a rinse reagent is applied to the locus of the suspect cancerous site, thus enhancing the rate of release of the agent from the mitochondria of the normal cells and further increasing the selectivity of the diagnostic methods.
• a method for selectively killing cancerous epithelial cells comprising the step of contacting cancerous cells in the locus of a suspect cancerous site with a cationic supravital mitochondrial marking agent, to cause cell death or to render the ' cancer cells substantially incapable of multiplication.
• the marking agent can be delivered to the cancer cells in a single discrete dose, or continuously, or in repeated discrete doses, with or without employing a rinse reagent after each dose.
• a method of improving the selectivity and cancer cell killing ability of cancer chemotherapeutic agents comprising the steps of either (1) forming a reaction product of a cationic supravital agent and a chemotherapeutic agent and delivering the reaction product to cancerous epithelial cells or (2) combining the cationic supravital agent with a cancer chemotherapeutic agent, to improve the selectivity or killing ability of the chemotherapeutic agent, either by additive or synergistic effects, or both.
• cationic supravital mitochondrial marking agents include dyes, including toluidine blue 0, alcian blue, malachite green, phenosafranin, acriflavine, pyronine Y, toluylene blue and brilliant green;
• non-dye compounds including peonidin, oxythiamine, tiemonium iodide, elliptinium acetate and furazolium chloride.
• the preferred mitochondrial marking agents are dyes of the oxazine and thiazine class.
• the thiazine dyes are especially preferred, particularly toluidine blue 0, Azure A, Azure B and ring-substitution and N- substitution analogs thereof.
• the marking agent or reaction product of marking agent + chemotherapeutic agent In order to be selectively absorbed and retained in cancer cell mitochondria, the marking agent or reaction product of marking agent + chemotherapeutic agent, must have a molecular weight of below about 5,000. Further, because of marked differences in the selective marking and therapeutic activity of various closely related analogs, it appears that the molecular structure of the marking agent significantly affects its ability to selectively mark and/or kill living cancer cells in the presence of normal living cells. These differences in cell marking and killing ability are related to structural features, e.g., location and type of ring- substituents and N-substituents, of the marking agent molecules that implicate one or more or all of the following mechanisms of action:
• the structure of the marking agent molecule e.g., position and nature of ring and N-substituents on the cationic molecule, affects the availability of the positive charge and hinders the ability of the marking agent or "stacked" groups of them to be attracted by the negative charges on the mitochondrial membranes or within the mitochondria.
• the structure of the marking agent molecule permits it to intercalate into or "stack" along the exterior of mitochondrial DNA of cancer cells.
• the structure of the marking agent molecule permits it or stacked groups of them to bind to specific active sites, e.g., four specific proteins, in the mitochondria, and/or precipitate with cardiolipins at the inner surface of the mitochondrial membrane.
• the structure of the marking agent affects its reduction potential and its tendency to change to the uncharged "leuco" form. 5.
• the structure of the marking agent affects its acidity (p a ) , and, in turn, the ability of the cationic marking agent to deprotonate at physiological pH .
• the cationic form of the dye can be attracted to the outer surface of the mitochondrial membrane, whereupon the dye cation can lose a proton and concomitantly lose its positive charge, thereby liberating the neutral form of the dye, which may more readily penetrate the nonpolar matrix of the membrane and gain access to the interior of the mitochondrion.
• Mechanisms 1 dye- membrane) , 2 (dye-base pair or dye-dye) , and 3 (dye- protein or dye-lipid) depend on the hydrophobicity- lipophilicity of the dye, which can be assessed by various means, one of which is the partition coefficient between aqueous solution and a low-polarity organic solvent, such as 1-octanol (i.e., log P values) .
• Mechanisms 4 and 5 depend on hydrophobicity- lipophilicity, due to the effect of differential solvation of reactant and product on reduction potential (oxidized vs. reduced forms) and p a (neutral vs. charged forms) .
• hydrophobicity hampers the solvation of protonated tertiary aliphatic amines (R 3 NH + ) , thereby decreasing their acidity relative to secondary amines (R 2 NH 2 + ) .
• a cationic supravital marking agent having a log P of from about -1.0 to about 5.
• Different concentrations of the various cationic marking agents at 100, 50, 10 and 1 ⁇ g/ml are prepared in RPMI medium complete with 20% fetal calf serum, 1 mM glutamine, hydrocortisone, insulin, transferrin, estradiol, selenium and growth hormone.
• the carcinoma cells are incubated at 37EC in tissue culture incubators with 5% C0 2 and 95% relative humidity, for 5 minutes with each agent and concentration there and then rinsed twice using 2 minute incubations with 1% acetic acid. After incubation and rinsing, the cells are harvested, at 30 min., 1 hour, 2 hours, 4 hours and 8 hours. The cells are then extracted with 2-butanol and analyzed by spectrophotometry for quantitation of the marking agent.
• the results show that there is a concentration dependence in the rate of accumulation of marking agent in the mitochondria of both carcinoma and normal cells and in the selectivity of release of the marking agent from cancer cells, but this concentration dependence starts to become less pronounced.
• the saturation concentration for toluidine blue 0 occurs at concentrations of lO ⁇ g/ml and above.
• the saturation concentrations for the other marking agents are similarly determined.
• the remaining experiments are conducted with a concentration of lO ⁇ g/ml for toluidine blue 0 and at the saturation concentrations for the other marking agents so-determined, unless stated otherwise.
• the mitochondrial localization of the agents is analyzed using confocal high resolution microscopy and phase contrast microscopy.
• Living cells are cultivated in complete growth medium with 20% fetal calf serum and growth factors, and maintained at 37EC. These cells accumulate and retain the marking agents in the mitochondria. When these cells are then maintained in an agent-free medium, carcinoma cells retain the agent for longer than about 1 hour, but normal epithelial cells release the agent within about 15 minutes.
• Known agents that alter the mitochondrial electrical potential are used to pretreat epithelial cancer cells, followed by treatment with the cationic supravital mitochondrial marking agents.
• These pretreatment agents include azide and cyanide preparations and dinitrophenol.
• Epithelial cancer cells are also pre-stained with the various dyes and then are post-treated with these known agents.
• the release of the dyes from the cells or the transfer of the dyes to other subcellular compartments, including the nucleus is analyzed.
• the cells pretreated with these agents do not accumulate dyes in the mitochondria and the mitochondria of the pre-stained cells release the dye upon post- treatment with these agents.
• Fresh explants of resected epithelial carcinomas are analyzed for marking agent uptake and retention. After resection, the carcinomas are microdissected from surrounding tissue, cut into 3 mm sections and maintained as explant tissue cultures at 37°C. These explants are then incubated with the various agents and then extracted for quantitation of the agent.
• Oral carcinoma have rapid uptake and prolonged retention of these agents.
• the agents start to be released from the cells after about one hour of cultivation in agent-free medium. However, the agents are released faster when the cells are incubated in medium that does not contain growth factors, fetal calf serum and other medium additives. The agents are also released faster when the cells are grown in adverse conditions such as lower temperatures.
• SqCHN Oral carcinoma
• normal epithelial cells quickly release the agents from their mitochondria and from the cell much more quickly. By 10-15 minutes, most of the agent is released from the mitochondria.
• the following adducts of cationic mitochondrial marking agents and various known chemotherapeutic agents are employed, with substantially similar results, except that the cancer cell kill rate and selectivity of the chemotherapeutic agent are substantially improved.
• a toluidine blue drug substance is prepared in accordance with the manufacturing procedures disclose in the U.S. Patent 6,086,852, issued to Burkett on July 11, 2000. Components of the drug substance are then fractionated and separated by semi-preparative HPLC, yielding the analogs identified in the ⁇ 852 patent as represented by Peaks 5, 6, 7 and 8.
• the compounds represented by peaks 7 and 8 are toluidine blue regioisomers, having the ring methyl group in the -2 position (peak 8) and the -4 position (peak 7) .
• the compound represented by peak 5 is the N-demethylated derivative of peak 7 and the compound represented by peak 6 is the N-demethylated derivative of peak 8.
• the compounds represented by peaks 5, 6, 7 and 8, obtained during the fractionation of the toluidine blue O, are analyzed for their selective toxicity towards living oral carcinoma cells (SqCHN) compared to living normal oral epithelial cells.
• SqCHN living oral carcinoma cells
• Separate cultures of squamous carcinoma cells and normal epithelial cells are incubated with the different dye fractions and then washed with dye-free medium. The cells are then re- incubated in growth medium and observed over a period of 8 days to determine the extent of cell killing.
• the compound of peak 6 results in 95% cell death of carcinoma cells, compared to only about 20% killing of normal cells.
• the compound of peak 8 shows 89% cell death of carcinoma cells whereas it only causes about 20% killing of normal cells.
• the selective retention of the compounds of peaks 6 and 8 is selectively toxic towards carcinoma cells.
• the selective introduction into the mitochondria of cationic dyes leads to disruption of the mitochondrial electrical potential which is the source of cellular energy and the driving force of ATP (adenosine triphosphate) production of the cells.
• ATP adenosine triphosphate
• the therapeutic characteristics of the compounds of peaks 6 and 8 are determined by further in-vi tro tests, conducted in the manner of Example 8, using other isolates of carcinoma cells and normal epithelial cells.
• the testing profile includes other squamous carcinomas of the head and neck, esophagus, lung, cervix and skin, as well as other types of cancers, including adenocarcinomas, lymphomas and sarcomas.
• In-vivo "delay of tumor growth” and "tumor regression assay” tests using tumor-bearing animals, including head and neck and lung carcinomas implanted in Balb-C mice, are made to analyze the in-vivo therapeutic benefit of these compounds.

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• 2000
  • 2000-02-28 WO PCT/US2000/005387 patent/WO2001064110A1/en not_active Ceased
  • 2000-02-28 AU AU2000237154A patent/AU2000237154A1/en not_active Abandoned
• 2001
  • 2001-02-27 CZ CZ20013861A patent/CZ20013861A3/cs unknown
  • 2001-02-27 WO PCT/US2001/006318 patent/WO2001064255A1/en not_active Ceased
  • 2001-02-27 RU RU2001132076/15A patent/RU2226404C2/ru not_active IP Right Cessation
  • 2001-02-27 IL IL14614101A patent/IL146141A0/xx unknown
  • 2001-02-27 AU AU43316/01A patent/AU785489B2/en not_active Ceased
  • 2001-02-27 MX MXPA01010886A patent/MXPA01010886A/es active IP Right Grant
  • 2001-02-27 CA CA002370741A patent/CA2370741A1/en not_active Abandoned
  • 2001-02-27 BR BR0104747-7A patent/BR0104747A/pt not_active Application Discontinuation
  • 2001-02-27 EP EP01916271A patent/EP1214101A4/de not_active Ceased
  • 2001-02-27 JP JP2001563152A patent/JP2003525044A/ja active Pending
  • 2001-02-27 NZ NZ515202A patent/NZ515202A/en unknown
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