Aksentijevich I, Cardarelli C O, Pastan I, Gottesman M M
Laboratories of Cell Biology and Molecular Biology, National Cancer Institute, NIH, Bethesda, Maryland 20892-4255, USA.
Clin Cancer Res. 1996 Jun;2(6):973-80.
In this work, we demonstrate a protective effect conferred by the human multidrug resistance gene (MDR1) to populations of the murine hematopoietic system against the toxic effects of bisantrene, a novel intercalating cytotoxic agent under investigation as an anticancer agent. In vitro, MDR1-expressing cell lines are highly cross-resistant to bisantrene, and low levels of P-glycoprotein (the MDR1 gene product cell surface protein) confer resistance to the drug. MDR1-positive mice were generated after transplantation of bone marrow cells (BMC) transduced in vitro with a MDR1 retrovirus. Control mice were transplanted with BMC transduced with the neomycin resistance gene. Administration of a single i.v. dose of 50 mg/kg of bisantrene resulted in a decrease of the total WBC count of approximately 40%. In contrast, a decrease of the total WBC count of only 17% was observed in mice transplanted with MDR1-transduced BMC. Immunofluorescence studies with cell lineage-specific monoclonal antibodies showed that bisantrene was specifically toxic for B lymphocytes and macrophages. Double-staining with MRK16 (a monoclonal antibody specific for P-glycoprotein) demonstrated that a single dose of bisantrene increased the relative number of MDR1-transduced positive B cells, macrophages, and (to some extent) granulocytes when compared to the number found in MDR1-untreated mice or the bisantrene-treated neomycin-transduced control mice. These results provide in vivo evidence that bisantrene is a hematotoxic drug capable of selecting for MDR1-transduced hematopoietic cells. Bisantrene might be useful for gene therapy as an in vivo selective agent for cells transduced with MDR1 vectors that also coexpress therapeutic genes of interest.
在本研究中，我们证明了人类多药耐药基因（MDR1）对小鼠造血系统群体具有保护作用，可抵御双胺苯吖啶的毒性作用。双胺苯吖啶是一种新型嵌入性细胞毒性药物，正作为抗癌药物进行研究。在体外，表达MDR1的细胞系对双胺苯吖啶具有高度交叉耐药性，低水平的P-糖蛋白（MDR1基因产物细胞表面蛋白）赋予对该药物的耐药性。用MDR1逆转录病毒体外转导骨髓细胞（BMC）后生成MDR1阳性小鼠。对照小鼠移植用新霉素抗性基因转导的BMC。静脉注射单次剂量50mg/kg双胺苯吖啶导致白细胞总数下降约40%。相比之下，移植MDR1转导BMC的小鼠中白细胞总数仅下降17%。用细胞谱系特异性单克隆抗体进行的免疫荧光研究表明，双胺苯吖啶对B淋巴细胞和巨噬细胞具有特异性毒性。用MRK16（一种对P-糖蛋白特异的单克隆抗体）进行双重染色表明，与未用MDR1处理的小鼠或经双胺苯吖啶处理的新霉素转导对照小鼠中发现的数量相比，单次剂量的双胺苯吖啶增加了MDR1转导的阳性B细胞、巨噬细胞以及（在一定程度上）粒细胞的相对数量。这些结果提供了体内证据，表明双胺苯吖啶是一种血液毒性药物，能够选择MDR1转导的造血细胞。双胺苯吖啶作为一种体内选择剂，对于用MDR1载体转导且还共表达感兴趣治疗基因的细胞，可能对基因治疗有用。
