AIM: To verify whether P-glycoprotein (P-gp) could induce cell resistance to apoptosis by inhibiting caspase-8 and caspase-3.METHODS: Human KB cells, either drug-sensitive or with multidrug resistance (MDR) phenotype ...AIM: To verify whether P-glycoprotein (P-gp) could induce cell resistance to apoptosis by inhibiting caspase-8 and caspase-3.METHODS: Human KB cells, either drug-sensitive or with multidrug resistance (MDR) phenotype caused by overexpression of P-gp (KBv200 cells), were treated with anti-Fas (CH-11 monoclonal antibody) to induce apoptosis.Cytotoxicity was detected by MTT assay. Symptoms of cell death were assessed by morphological observation after Hoechst33258 staining, activation of caspase-8 and caspase-3 was measured by Western blotting.RESULTS: Compared with KB cells, the resistance of KBv200 cells to VCR (vincristine) was about 51-fold higher.Anti-Fas (CH-11) induced cytotoxicity and apoptosis in both sensitive KB cells and MDR phenotype KBv200cells. The IC50 of CH-11 in KB cells was similar to that in KBv200 cells. CH-11 induced similar apoptotic rates in both KB cells and KBv200 cells, which could be classified as caspase-dependent apoptotic pathway. Verapamil (VRP) did not affect CH-11-mediated apoptosis in KBv200 cells.CONCLUSION: Expression of P-glycoprotein does not induce resistance to caspase-8 and -3 activation or antiFas-induced cell apoptosis.展开更多
基金Supported by the Natural Science Foundation of Guangdong Province,No.021813National Natural Science Foundation of China,No.30371659
文摘AIM: To verify whether P-glycoprotein (P-gp) could induce cell resistance to apoptosis by inhibiting caspase-8 and caspase-3.METHODS: Human KB cells, either drug-sensitive or with multidrug resistance (MDR) phenotype caused by overexpression of P-gp (KBv200 cells), were treated with anti-Fas (CH-11 monoclonal antibody) to induce apoptosis.Cytotoxicity was detected by MTT assay. Symptoms of cell death were assessed by morphological observation after Hoechst33258 staining, activation of caspase-8 and caspase-3 was measured by Western blotting.RESULTS: Compared with KB cells, the resistance of KBv200 cells to VCR (vincristine) was about 51-fold higher.Anti-Fas (CH-11) induced cytotoxicity and apoptosis in both sensitive KB cells and MDR phenotype KBv200cells. The IC50 of CH-11 in KB cells was similar to that in KBv200 cells. CH-11 induced similar apoptotic rates in both KB cells and KBv200 cells, which could be classified as caspase-dependent apoptotic pathway. Verapamil (VRP) did not affect CH-11-mediated apoptosis in KBv200 cells.CONCLUSION: Expression of P-glycoprotein does not induce resistance to caspase-8 and -3 activation or antiFas-induced cell apoptosis.
