蛋白激酶C的下调与KBV200细胞多药耐药性的关系

Down-Regulation of PKC and Multidrug Resistance in KBV200 Cells

目的 探讨蛋白激酶C (PKC)在肿瘤多药耐药 (MDR)中的作用。方法 3 2 P掺入法测定PKC的活性 ;Westernblot法检测KBV2 0 0细胞株PKC亚型的表达和亚细胞分布 ;实验组用十字孢碱 (SP)预孵育KBV2 0 0细胞 ;MTT法检测耐药株KBV2 0 0细胞的耐药性。结果 SP可下调膜组分和浆组分的PKC活性及总活性 ;使PKCα膜组分和浆组分的表达均降低 ,PKCβ的膜组分消失 ,浆组分PKCβ的表达稍增强 ,PKCε的膜组分和浆组分表达无变化 ;SP可降低VCR、ADR对KBV2 0 0细胞的IC50 值 (P <0 0 1)。结论 SP使KBV2 0 0细胞耐药性降低 ,可能与下调PKC有关。

Objective To investigate the relationship between protein kinase C(PKC) and multidrug resistance(MDR) in KBV200 cells.Methods PKC activity was assayed by the measurement of the incorporation of 32 P from [γ- 32 P]ATP into peptide substrates.Western blot was used for the assessment of PKC isoform expression.PKC inhibitor SP was used to preincubate KBV200 cells to evaluate the importance of PKC in MDR.The cell inhibitory rate was evaluated by MTT.Results The PKC activity of membrane and cytosol fraction was lower in SP group than that in control group(P<0.01).PKCα expression was downregulated especially in membrane fraction after SP preincubation.PKCβ expression was increased slightly in cytosol fraction but disappeared in membrane fraction.The values of IC 50 of VCR and ADR in SP group were decreased to 251.8 nmol/L and 58.69 nmol/L respectively.Conclusions SP(PKC inhibitor) could decrease the multidrug resistance of KBV200 cells,suggesting that PKC may be involved in the mechanism of multidrug resistance of tumor cells.