Pharmacology Division

5. Pharmacology Division

　The research program in the Pharmacology Division focuses on the discovery of new approaches for treatment of cancer that can be translated to the clinic. Basic and applied immunological and pharmacological research is critical for the rational development and effective use of anti-cancer immuncompetent cells and drugs. A major focus is fundamental research on the anti-tumor mechanisms of immunocompetent cells and drugs, and the cellular and molecular determinants of the recognition of tumor cells and drug sensitivity and resistance. The more applied research projects include the development of appropriate schedules of different types of effector cells and drugs for cancer treatment including; (1) cell therapy using the newly discovered T-cell subset, NK-like T cells, as strong anti-tumor effector cells, (2) the clinical application of combined modalities such as combination chemotherapy, adjuvant therapy, and chemogenotherapy, (3) clinical phase I, II and III studies using dendritic cells and anti-cancer drugs, and (4) pharmacokinetic and pharmacodynamic analyses in clinical investigation.
Anti-Tumor Immunity of NK-Like T Cells

　Intermediate T-cell receptor (TCR^int) cells or natural killer (NK)-like T (NKT) cells are a newly found T-cell subset and play an important role in various immune responses including anti-tumor immunity. The U5A2-13 monoclonal antibody (mAb) was established using tMK-2U cells derived from TCR^int cells of BALB/c nude mice.⁽⁹¹⁾ U5A2-13 antigen was expressed on 65% of TCR^int cells in the liver of the various mouse strains including both NK1.1⁺ and NK1.1^- mouse strains. U5A2-13⁺ cells were wholly a subset of IL-2Rb⁺ TCR^int cells. More than 85% of U5A2-13⁺ cells co-expressed NK1.1 antigen, whereas a small number of both U5A2-13⁺NK1.1^- and U5A2-13-NK1.1⁺ populations were also observed. Therefore U5A2-13 mAb can recognize a similar population to NKT cells.
　The anti-metastatic effect of U5A2-13⁺ T cells was examined. When U5A2-13 antibody was injected into the tail vein of B6 mice, all U5A2-13⁺ T cells were completely eliminated by day 14, but interestingly TCR^int cells, NK1.1⁺ T cells or NK cells remained. On day 1, B16 melanoma cells were injected into the spleen and on day 14, the number of metastatic nodules in the liver was counted. The disapearance of U5A2-13⁺ T cells, but not NK1.1⁺ T cells, resulted in a significant increase in metastases in the liver. U5A2-13⁺ T cells may therefore play an important role in tumor metastasis.
Biological and Biochemical Pharmacology

　Research has focused on understanding the molecular mechanisms by which drugs kill tumors and the identification of molecular targets for specific anticancer drugs. Factors involved in activation and metabolism of anticancer agents are also of interest. Major research areas include elucidation of mechanisms of anti-tumor effects involving DNA topoisomerases,⁽⁹²⁾ DNA damage,⁽⁹³⁾ cell cycle regulation, intracellular signaling pathway,^(94-96) and microtubule dynamics.⁽⁹⁷⁾
Drug Resistance

　Drug resistance in tumor cells is frequently observed in patients receiving chemotherapeutic agents. A fundamental approach to drug resistance is to determine the molecule responsible for resistance to each drug.⁽⁹⁸⁾ Mechanisms of cisplatin resistance include the decreased intracellular accumulation of drugs caused by increased active efflux⁽⁹⁹⁾ and the increased capacity of the detoxification mechanisms mediated by glutathione.^(98,100)
　The mechanisms of resistance to DX-8951f, a novel camptothecin derivative were investigated in human lung cancer cells. The DX-8951f-resistant cells showed no decrease in topoisomerase I activity but a decreased capacity of cleavable complex formation with the drug and DNA.⁽⁹²⁾
　The mechanisms of action of a novel anti-mitotic agent, E7010 were investigated. E7010 exerts anti-tumor activity through binding to the colchicine-binding sites of b-tubulin. An isotype imbalance of b-tubulin was observed in the E7010-resistant cells. The antimitotic agents show different binding activities for each b-tubulin isotype.⁽¹⁰¹⁾
Combination Therapy

　A new 3-dimensional technique to evaluate the combination effect has been developed. For the combination of KRN5500 and TAS103, concomitant use of these agents with platinum showed greater anti-tumor effects on lung cancer cells. Other related clinical studies are listed.^(102-104)
Induction of Glutathione Synthesis-related Proteins

　The cerebral and hepatic reduced glutathione (GSH) levels were increased soon after irradiation with 50 cGy of g-rays. The increase in GSH was considered to be a consequence of the induction of GSH synthesis-related proteins including thioredoxin and glutathione reductase.^(105,106)




	5. Pharmacology Division



		The research program in the Pharmacology Division focuses on the discovery of new approaches for treatment of cancer that can be translated to the clinic. Basic and applied immunological and pharmacological research is critical for the rational development and effective use of anti-cancer immuncompetent cells and drugs. A major focus is fundamental research on the anti-tumor mechanisms of immunocompetent cells and drugs, and the cellular and molecular determinants of the recognition of tumor cells and drug sensitivity and resistance. The more applied research projects include the development of appropriate schedules of different types of effector cells and drugs for cancer treatment including; (1) cell therapy using the newly discovered T-cell subset, NK-like T cells, as strong anti-tumor effector cells, (2) the clinical application of combined modalities such as combination chemotherapy, adjuvant therapy, and chemogenotherapy, (3) clinical phase I, II and III studies using dendritic cells and anti-cancer drugs, and (4) pharmacokinetic and pharmacodynamic analyses in clinical investigation. Anti-Tumor Immunity of NK-Like T Cells 　Intermediate T-cell receptor (TCR^int) cells or natural killer (NK)-like T (NKT) cells are a newly found T-cell subset and play an important role in various immune responses including anti-tumor immunity. The U5A2-13 monoclonal antibody (mAb) was established using tMK-2U cells derived from TCR^int cells of BALB/c nude mice.⁽⁹¹⁾ U5A2-13 antigen was expressed on 65% of TCR^int cells in the liver of the various mouse strains including both NK1.1⁺ and NK1.1^- mouse strains. U5A2-13⁺ cells were wholly a subset of IL-2Rb⁺ TCR^int cells. More than 85% of U5A2-13⁺ cells co-expressed NK1.1 antigen, whereas a small number of both U5A2-13⁺NK1.1^- and U5A2-13-NK1.1⁺ populations were also observed. Therefore U5A2-13 mAb can recognize a similar population to NKT cells. 　The anti-metastatic effect of U5A2-13⁺ T cells was examined. When U5A2-13 antibody was injected into the tail vein of B6 mice, all U5A2-13⁺ T cells were completely eliminated by day 14, but interestingly TCR^int cells, NK1.1⁺ T cells or NK cells remained. On day 1, B16 melanoma cells were injected into the spleen and on day 14, the number of metastatic nodules in the liver was counted. The disapearance of U5A2-13⁺ T cells, but not NK1.1⁺ T cells, resulted in a significant increase in metastases in the liver. U5A2-13⁺ T cells may therefore play an important role in tumor metastasis. Biological and Biochemical Pharmacology 　Research has focused on understanding the molecular mechanisms by which drugs kill tumors and the identification of molecular targets for specific anticancer drugs. Factors involved in activation and metabolism of anticancer agents are also of interest. Major research areas include elucidation of mechanisms of anti-tumor effects involving DNA topoisomerases,⁽⁹²⁾ DNA damage,⁽⁹³⁾ cell cycle regulation, intracellular signaling pathway,^(94-96) and microtubule dynamics.⁽⁹⁷⁾ Drug Resistance 　Drug resistance in tumor cells is frequently observed in patients receiving chemotherapeutic agents. A fundamental approach to drug resistance is to determine the molecule responsible for resistance to each drug.⁽⁹⁸⁾ Mechanisms of cisplatin resistance include the decreased intracellular accumulation of drugs caused by increased active efflux⁽⁹⁹⁾ and the increased capacity of the detoxification mechanisms mediated by glutathione.^(98,100) 　The mechanisms of resistance to DX-8951f, a novel camptothecin derivative were investigated in human lung cancer cells. The DX-8951f-resistant cells showed no decrease in topoisomerase I activity but a decreased capacity of cleavable complex formation with the drug and DNA.⁽⁹²⁾ 　The mechanisms of action of a novel anti-mitotic agent, E7010 were investigated. E7010 exerts anti-tumor activity through binding to the colchicine-binding sites of b-tubulin. An isotype imbalance of b-tubulin was observed in the E7010-resistant cells. The antimitotic agents show different binding activities for each b-tubulin isotype.⁽¹⁰¹⁾ Combination Therapy 　A new 3-dimensional technique to evaluate the combination effect has been developed. For the combination of KRN5500 and TAS103, concomitant use of these agents with platinum showed greater anti-tumor effects on lung cancer cells. Other related clinical studies are listed.^(102-104) Induction of Glutathione Synthesis-related Proteins 　The cerebral and hepatic reduced glutathione (GSH) levels were increased soon after irradiation with 50 cGy of g-rays. The increase in GSH was considered to be a consequence of the induction of GSH synthesis-related proteins including thioredoxin and glutathione reductase.^(105,106)