多药耐药基因转染对肝癌小鼠大剂量化疗支持作用

Chemoprotective effect of multidrug resistance 1 gene transfer to hematopoietic progenitor cells on mice with cancer allows receiving intensified chemotherapy

目的观察多药耐药(MDR1)基因保护骨髓进行大剂量化疗杀伤肿瘤及在体内表达情况。方法BALB/C小鼠H22肝癌模型,^(60)Co-γ照射,移植转染MDR1的骨髓造血细胞后化疗,计数白细胞,测定瘤体大小;外周血、骨髓、脾、肿瘤等行P-糖蛋白免疫组织化学,流式细胞术以及MDR1 RT-PCR,PCR检测。结果MDR1转染小鼠白细胞明显较高(P<0.01),单纯骨髓移植小鼠白细胞前3周高于BC组,第4周后差异无统计学意义;化疗剂量较大抑瘤率高。MDR1转染后肿瘤组织无P-糖蛋白表达;外周血,肾PCR检测有特异条带而RT-PCR检测未发现。结论MDR1保护骨髓支持大剂量化疗可抑制肿瘤生长。外源MDR1仅在骨髓有效表达。

Objective To investigate human multidrug resistance （hMDR1） gene transfer to pre- vent bone marrow toxicity from chemotherapy agents and its expression in mice in vivo. Methods Hematopoietic progenitor cells served as targets of MDR1 gene transfer by the mediation of retrovirus vector and engrafted into the tumor-bearing BALB/C mice with ^60Co-γ ray exposure in advance. The MDR1 gene was detected by PCR, RT-PCR, flow cytometry and immunocytochemistry at 6th week. Results Doxorubicin （ADM） suppressed tumor growth of the xenograft significantly in a dose-dependence manner if supported by suitable peripheral WBC. WBCs count revealed that doxorubicin-treated mice that had received gene- transduced cells showed a significant increase in WBCs count compared with their gene-transduced-naive counterparts. The MDRI mRNA expression was detected in bone marrow. Tail vein blood and spleens contained measurable amounts of MDRI DNA and no transcripts of the MDRI gene. Tumor tissue had no MDRI DNA and MDRI mRNA expression. Conclusion MDR1 gene therapy may provide some degrees of chemoprotection so can increase the chemotherapy dose to kill tumor cells.