CYP3A5参与急性白血病耐药机制的研究

Study of CYP3A5 in drug resistance mechanisms in acute leukemia

目的 探讨细胞色素P4 5 0 3A亚家族多肽 5 (CYP3A5 )在急性白血病 (AL)耐药机制中的作用。方法 RT PCR、免疫组化、MTT法检测白血病细胞株、AL患者原代细胞CYP3A5转录表达与细胞株对化疗药物敏感性、患者化疗疗效及预后的相关性 ,检测化疗药物对CYP3A5的转录调控 ;构建CYP3A5重组质粒稳定转染HL 6 0细胞 ,观察细胞对化疗药物的敏感性是否改变。结果 转录CYP3A5的K5 6 2、U937细胞与不转录CYP3A5的NB4、HL 6 0细胞相比 ,对柔红霉素明显耐受 (耐药倍数均为 2 1倍 ) ;原发耐药组患者初治时CYP3A5阳性率 (17.2 % )显著高于持续完全缓解 (CCR)组 (0 .4 % )与继发耐药组初治时 (5 .4 % ) ,早期复发组第 1次完全缓解 (CR1 )时阳性率 (2 3.9% )显著高于CCR组CR时(1 3% ) ;柔红霉素可诱导K5 6 2 A0 2、HL 6 0 ADR细胞CYP3A5转录 ;HL 6 0细胞稳定转染CYP3A5重组质粒后明显耐受柔红霉素、长春新碱 (耐药倍数分别为 3.0 ,4 .0倍 )。结论 白血病细胞表达CYP3A5可能使其原位代谢多种化疗药物 ,是直接导致AL耐药的机制之一。

Objective To investigate if CYP3A5 is involved in drug resistances mechanisms of acute leukemia. Methods By using RT-PCR, immunohistochemistry and MTT assay, CYP3A5 mRNA and protein were detected in leukemia cell lines and acute leukemia patients, meanwhile transcriptional regulation of CYP3A5 induced by daunorubicin was observed. A pcDNA3-CYP3A5 reconstituted plasmid and its stably transfected cell line HL-60/CYP3A5 were both estabolished. Results CYP3A5 mRNA was detected in K562 and U937 cells, whose IC 50 values of daunorubicin were 2.1-fold higher than those of NB4 and HL-60 cells. Bone marrow CYP3A5 positive blast cell percentage at the time of diagnosis in primary drug resistance group(17.2%)was significantly higher than that of continuous complete remission(CCR) group(0.4%) and secondary drug resistance group(5.4%). In their first complete remission of the early relapsed group, the positive rate had been 23.9% as compared with that of CCR group (1.3%). Daunorubicin increased CYP3A5 mRNA level in K562/A02 and activated its transcription in HL-60/ADR. HL-60/CYP3A5 cell was significantly resistant to daunorubicin and vincristine than HL-60 cells did (3.0 and 4.0 times, respectively). Conclusion CYP3A5 expressed in leukemia cells may cause in situ metabolization of many kinds of anticancer drugs, thus led to drug resistance.