| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
KFr13 (KFR) showed more than 3 fold sensitivity than OVCAR-2 (OV) for TXL,while IC50 of CDDP was 6 fold much as that of OV.KFr13 also showed 14 fold resistant to ADM than OV.KFR is able to be classified to ADM-resistant. This result suggests that CDDP-resistant cells are sensitive to TXL.The mechanisms of this result are not clear. Cell cycle changes are significant by 1mu and 0.1muM TXL.Both KFR and OV were accumulated to G2+M phase by 1mu and 0.1muM TXL.While 0.01muM TXL showed no significant growth suppression to KFR and OV,this concentration of TXL resulted sub-G1 peak in OV.Using laser scanning cytometry, from sub-G1 area where few signals existing, morphological apoptotic cells were observed. In KFR,apoptotic cells induced by TXL were existing in G2 phase, not but M phase or other cell cycle phases. From sub-G1 area, only particles of apoptotic bodies were observed. These discrepancies resulted from differences of sensitivities to drugs of cell lines.
Apoptag occasionally showed p
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ositive staining in apoptotic cells, even though cells showed apoptosis morphologically. Apoptag staining procedure is relatively simplified and easy to perform at constant manner. The mechanisms to explain this result are needed to be further investigated. OV showed apoptosis often by drug exposure. The fact that floating cells of OV from control group demonstrated apoptosis is suggesting that special pass ways are existing to induce apoptosis in OV.
Bcl-2beta in floating cells treated by 1muM TXL are an attractive result. bcl-2 gene was originally understood to code two proteins, Bcl-2alpha and Bcl-2beta. It is not yet clear when and how this 21 kDa protein was produced during TXL exposure. TXL may affect mitochondria directly or via changing the intracellular structures inducing hyperpolimerization of tubulins. There is no information about KFR regarding to relationship between status of Bcl-2 protein and cell cycle. Judging from data we obtained by flow cytometry, KFR expressed Bcl-2 protein without cell cycle specific manner.
Expression of Cyclin D1 and B1 were changed dramatically by TXL exposure. 0.01mu TXL resulted expression of both cyclin D1 and B1 in all cell cycle phases in KFR and OV.As shown in Figures 2 and 4,0.01muM TXL did not affect cell growth in KFR and OV,even a low concentration of TXL has an effect to alter cell cycle check point proteins. The expression of cyclin D1 and B1 in control cells are observed in all cell cycle phases. Further investigation is required. Less
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