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目的 探讨IL—4基因修饰对肝细胞癌多药耐药(MDR)的逆转作用及可能机制。方法 用逆录病毒载体将IL—4基因导入人肝癌细胞细胞系HepG2,采用MTT生物活性法检测药物敏感性。间接免疫荧光染色流式细胞仪分析P—糖蛋白(P—gP)。微量荧光分光光度法分析癌细胞内ADM聚集量。结果 IL—4基因修饰显著提高癌细胞对多种化疗药物的敏感性(耐药逆转倍数在6～32倍间)及增加ADM在癌细胞内聚集;P—gP阳性表达率(5％±0.6％)较野生型及空载体修饰细胞(98.5％+0.5％)明显降低。逆转作用可为PKC激活剂TPA所阻断。IL—4基因修饰瘤苗及其培养上清与野生型细胞共培养,也可使野生型瘤细胞产生逆转效应。结论 IL—4基因修饰可通过自分泌、旁分泌形式逆转肝癌细胞MDR,此作用可能与其下调P—gP表达及抑制PKC活性有关。
Objective To investigate the reversal effect of IL-4 gene modification on multidrug resistance (MDR) in hepatocellular carcinoma and its possible mechanism. Methods IL-4 gene was transduced into HepG2 cell line of human hepatocellular carcinoma cell line with retroviral vector and the drug sensitivity was detected by MTT bioassay. Indirect immunofluorescence staining was used to analyze P-glycoprotein (P-gp). Microfluidic spectrophotometric analysis of ADM accumulation in cancer cells. Results The IL-4 gene modification significantly increased the sensitivity of cancer cells to various chemotherapeutic drugs (6 to 32 fold of the fold change in drug resistance) and increased ADM accumulation in cancer cells. The positive rate of P-gp expression (5% ± 0.6 %) Was significantly lower than wild-type and empty vector-modified cells (98.5% + 0.5%). The reversal can be blocked by TPA, a PKC activator. IL-4 gene-modified tumor vaccine and its culture supernatant and wild-type cells co-cultured, but also make wild-type tumor cells have a reversal effect. Conclusion IL-4 gene modification can reverse the MDR of hepatocellular carcinoma cells by autocrine and paracrine forms, which may be related to down-regulation of P-gp expression and inhibition of PKC activity.