目的 研究缺氧对化疗药物敏感性的影响及药物转运蛋白和凋亡相关蛋白的变化,探讨缺氧条件下胃癌细胞发生多药耐药的机制.方法 通过MTT比色法检测胃癌细胞SGC7901在缺氧和常氧状态下对化疗药物敏感性的差异;利用Annexin V/PI染色法检测缺氧对化疗药物诱导的凋亡的影响;利用阿霉素的蓄积和潴留实验检测缺氧与常氧条件下胃癌细胞SGC7901阿霉素的潴留和蓄积的差异;利用Western blot 和RT-PCR方法检测不同时间缺氧处理胃癌细胞SGC7901中药物转运蛋白p-gp和MRP的变化以及凋亡相关分子Bcl-2和Bax的变化.结果 缺氧能够显著降低胃癌细胞对化疗药物的敏感性,并能够降低化疗药物诱导的凋亡和药物在细胞内的潴留和蓄积;缺氧能够显著上调MDR1和MRP1基因的表达以及增加其产物p-gp和MRP的蛋白水平;缺氧能够显著增加抗凋亡分子Bcl-2 mRNA和蛋白水平以及降低促凋亡分子Bax的表达.结论缺氧加剧胃癌细胞的多药耐药表型,其主要是通过上调药物转运蛋白的表达及增加抗凋亡分子Bcl-2/Bax的比例实现的.%Objective To study hypoxia-induced the chemotherapeutic drug sensitivity, exploit the mechanism of hypoxia-induced drug resistance in gastric cancer cells and characterize the role of drug transporter proteins and apoptotic relative protein contributing to hypoxia-induced MDR. Methods MTT assay, Annexin V/PI staining and Adriamycin accumulation and retention were used to determine the sensitivity of those cells to chemotherapeutic drugs under normoxic and hypoxic condition. By semiquantitative RT-PCR and Western blot, the expression of MDR, MRP, Bcl-2 and Bax were measured in the cells exposed to hypoxic condition at indicated times. Results Under hypoxic condition, gastric cancer cells revealed an increased drug resistance toward different chemotherapeutic drugs, a decrease apoptosis index induced by chemotherapeutics and a decrease accumulation and retention of ADR. Semiquantitative RT-PCR and Western blot results revealed that hypoxia increased the expression of MDR, MRP, Bcl-2 mRNA and protein, and decreased the expression of Bax mRNA and protein. Conclusion Hypoxia prompts multidrug resistance (MDR) phenotype via upregulating drug transporter protein MDR and increasing anti-apoptotic molecular ratio of Bcl-2 and Bax.
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