氯化两面针碱体外逆转KBV200多药耐药性的机制初步探讨

The Mechanism of Reversal Effect of Nitidine Chloride in KBV200 Cells in Vitro

目的初步探讨氯化两面针碱(nitidine chloride,NC)逆转KBV200细胞株的体外机制。方法用MTT法测定NC对KBV200细胞的逆转作用及量效关系。免疫细胞化学(ICC)法检测单用NC及NC联合长春新碱(VCR)处理KBV200后,细胞中的耐药相关蛋白P-gp和LRP的量、GST-π和TOPO-Ⅱ的活性,以及肿瘤细胞调亡蛋白P53及Bcl-2/Bax比值的变化。结果 0.3,0.6和1.2μg.ml-1的NC分别联合VCR对KBV200的逆转倍数分别为2.44,5.54和1.14倍。与单用VCR组相比,NC联合VCR组上调P53的表达(P<0.01),增强TOPO-Ⅱ活性(P<0.01),下调P-gp和LRP的表达(P<0.01),下调Bcl-2/Bax的比值。结论 NC具有逆转人口腔鳞癌细胞KBV200多药耐药性的作用,其机制可能与提高肿瘤细胞内药物的累积量和促进肿瘤细胞的凋亡有关。

Objective The mechanism of reversal multidrug resistance of human oral squamous carcinoma cells KBV200 by niti- dine chloride （NC） was investigated in vitro. Methods The cytotoxicity of NC in KBV200 cells was detected by MTT assay. The expression of resistance - associated proteins P - gp and LRP, the activity of GST - π, TOPO - Ⅱ, and the tumor cell apoptosis proteins P53 and ratio changes of Bcl - 2/Bax were determined by immunocytoehemistry （ICC）. Results 0. 3,0.6 and 1.2 μg .ml^-1 NC combined with VCR reversed the MDR by 2.44,5.54 and 1.14 -fold respectively. NC could sensitize to KBV200 cells, up - regulated the expression of P53 and down - regulated the expression of P - gp （ P 〈 0.01 ）. The expression of LRP and the ra- tio of Bcl - 2/Bax decreased （ P 〈 0.01 ） after treatment with NC. The activity of TOPO - Ⅱobviously increased （ P 〈 0.01 ） after treatment with NC. Conclusion The results suggest that NC is potent MDR - reverse agent to KBV200 cells in vitro. The mecha- nism is probably associated with down - regulating the expression of P - gp and LRP, thus increasing the concentration of anti - tumor drugs inside MDR - resistant cells ; down - regulating Bcl - 2/Bax value, and up - regulating the expression of P53 to pro- mote apoptosis of KBV200.