| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1994: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Sensitivities of three leukemic cell lines, K562, HL60, KG1, toward etoposide (VP-16), cisplatin (CDDP), cytosine arabinoside (Ara-C) and 4- hydroperoxycyclophosphamide (4HC) were investigated using polymerase chain reaction (PCR) technique. DNA was extracted from cells after short term treatment (4 hours) with CDDP,then target genomic region was amplified. Reduction of the amount of PCR product was observed in the cases of CDDP-treated HL60 and KG1 cells which showed morphological changes of apoptosis. Furthermore, the similar effect on PCR amplification was also found in the case of CDDP-treated K562 cells which did not show such morphological changes. Conceivably, it is not DNA fragmentation but CDDP-induced DNA crosslinks that is relevant to the reduction of the amplified PCR product. However, short term exposure to VP-16, Ara-C,or 4HC did not clearly show such effects. When DNA from the cells exposed with drug for 3 days was used as template, PCR-based dose-response curves were compatible with those obtained by tetrazolium reduction assay. In vitro drug sensitivity assay does not necessarily predict the clinical outcome, since the in vitro culture condition is not the same as in vivo milieu. In addition, combination chemotherapy is usually performed in clinical field. Comparison of dose-response curves of leukemic cells against anti-cancer drugs at onset with those at relapse may bring some contribution to chemotherapeutic strategy for individual patient. When degree of amplification of leukemic cell-specific DNA region is quantified after drug treatment, drug sensitivity of leukemic cells among many normal cells could be analyzed in vitro.
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