Basic study to establish molecular diagnosis and gene therapy for anticancer drug-resistant cancer cells

(1)抗癌耐药癌细胞的细胞和分子表征：利用来自人子宫癌和卵巢癌的100多个抗癌耐药亚克隆，对其药物敏感性进行定量评价，并与耐药亚克隆mRNA表达谱结果进行比较。本研究首次发现了死亡相关蛋白激酶（death-associated protein kinase， DAPK）与癌细胞抗癌药物敏感性的关系。子宫癌细胞去甲基化诱导DAPK表达，恢复其sn38敏感性。sn38耐药细胞的去甲基化恢复了sn38敏感性，而cdp耐药细胞的去甲基化不影响其cdp敏感性。(2)耐药亚克隆的mRNA表达谱：cDNA微阵列分析揭示了耐药亚克隆的mRNA表达谱。特别是，在许多抗癌耐药亚克隆中，c-myc mRNA的表达被显著抑制。(3)抑制mRNA表达可能揭示药物敏感性调节分子的候选基因：我们利用siRNA程序发现了药物敏感性调节分子的候选基因。研究STAT3的表达与肿瘤药物敏感性的关系。(4)耐药癌细胞基因治疗的基础研究：近期我们发现激活素A可以完全抑制tgf - β 1的生长抑制信号，表明激活素A在子宫内膜腺癌中的升高间接促进了癌细胞的增殖。作为基因治疗的靶点；我们正在研究刺激肿瘤组织中激活素A产生的调节因子。(5)同步放化疗的基础研究：在宫颈SCC细胞的体外实验中，我们找到了抗癌药物与放疗的最佳组合。

(1)Cellular and molecular characterization of anticancer drug-resistant cancer cells : Using more than 100 anticancer drug-resistant subclones derived from human uterine and ovarian carcinomas, their drug-sensitivities were quantitatively evaluated and compared to the results of mRNA expression profiling of the resistant subclones. In this study, we have first found some relationships of death-associated protein kinase (DAPK) and anticancer-drug sensitivities of cancer cells. Demethylation of uterine cancer cells induced DAPK expression and restored their SN38-sensitivity. Demethylation of SN38-resistant cells restored SN38-sensitivity while demethylation of CDDP-resistant cells did not affect their CDDP-sensitivities.(2)mRNA expression profiling of the drug-resistant subclones : cDNA microarray analyses revealed mRNA expression profiling of the drug-resistant subclones. Especially, c-myc mRNA expressions were significantly suppressed in many anti-cancer drug-resistant subclones.(3)Suppression of mRNA expression may disclose candidate genes of drug-sensitivity-regulating molecules : By using siRNA procedure, we have been discovering candidate genes of drug-sensitivity-regulating molecules. Relationship of STAT3 expression and anticancer drug-sensitivity has been investigated.(4)Basic study on gene therapy for drug-resistant cancer cells : Recently we have identified that growth-inhibitory signals of TGF-beta1 can be completely inhibited by activin A, indicating increased activin-A in endometrial adenocarcinoma indirectly enhance cell proliferation of the cancer cells. As targets for gene therapy, therefore ; we are investigating the regulatory factors that stimulate activin A production in cancer tissues.(5)Basic study for concurrent chemoradiation : In in vitro experiments with cervical SCC cells, we have found optimal combination of anticancer drugs with radiotherapy.