十字饱碱逆转耐药性KB细胞多药抗药性的机制

Mechanism of staurosporine in reversing multidrug resistance in KB cell to vicristine

目的:研究蛋白激酶C抑制剂十字饱碱(staurosporine,ST)逆转耐长春新碱KB细胞(简称KB/VCR)的机制。方法:用MTT法比较ST作用前后KB/VCR细胞耐药性的改变,用流式细胞术观察KB/VCR药物代谢的变化,用RTPCR法和免疫组织化学方法研究耐药膜糖蛋白(Pglycoprotein,Pgp)、耐药相关蛋白(multidrugresistanceassociatedprotein,MRP)和肺耐药蛋白(lungcancerresistancerelatedprotein,LRP)在细胞mRNA水平和蛋白水平上的表达。结果:1ng/mLST使KB/VCR细胞耐药性下降了158倍。亲本株KB/S细胞几乎不表达Pgp,而KB/VCR细胞却近100%强表达Pgp,P=0.004;ST使KB/VCR细胞的Pgp表达强度明显降低,但阳性率未见明显改变。MRP在两种细胞的基因转录水平和蛋白水平均呈现弱表达,ST也不影响其表达。1ng/mLST作用24h后,KB/S和KB/VCR细胞的LRP在mRNA水平及蛋白水平上表达指数均明显地高出用药前,P=0.006。结论:ST可通过降低Pgp表达强度和药物外排功能来逆转肿瘤细胞的多药抗药性,但这种作用可部分地被LRP蛋白表达增强所抵消。

OBJECTIVE:To identify the mechanism of staurosporine (ST), a PKC inhibitor, in reversing the multidrug resistance in KB cell to vicristine(KB/VCR). METHODS: MTT assay was applied to compare the change of reverse degree,after and before treating KB/VCR with ST. Flow cytometry was applied to observe the change of drug intracellular accumulation and efflux in KB/VCR cells. RT-PCR and cytoimmunochemistry were used to observe the expression of P-gp, MRP and LRP in the level of mRNA and protein. RESULTS: When treated with 1 ng/mL ST, the drug resistance index decreased 15 folds. The P-gp were strongly expressed in 100% KB/VCR cells but quite weakly expressed in KB/S cells,P=0.004. After treating KB/VCR with ST, the expressions of P-gp decreased evidently; the expression of MRP in these cells were weak in the level of gene transcription and cell, and ST did not influence the expression of MRP; 24 hours after the treatment with 1 ng/mL ST, the mRNA expression index and the expression of protein of LRP in KB/S cells and KB/VCR cells increased evidently, P=0.006. CONCLUSION: ST can reverse the multidrug resistance in cancer cell by decreasing the expression of P-gp and drug efflux, but this reversion can partly be counteracted by the increase of LRP expression.