阿霉素（Adriamycin，ADR）和依托泊苷是临床常用的肿瘤化学治疗药物，主要作用机制为抑制DNA拓扑异构酶，导致DNA双链断裂（double—strand DNA breaks，DSB）。肿瘤细胞发生耐药与多种机制有关，其中对DNA损伤修复的影响是其中重要的...阿霉素（Adriamycin，ADR）和依托泊苷是临床常用的肿瘤化学治疗药物，主要作用机制为抑制DNA拓扑异构酶，导致DNA双链断裂（double—strand DNA breaks，DSB）。肿瘤细胞发生耐药与多种机制有关，其中对DNA损伤修复的影响是其中重要的一环。端粒重复序列结合因子2（telomeric repeat binding factor2，TRF2）能够通过维持端粒末端的T环结构，防止端粒被DNA损伤修复机制检测为DSB，维持端粒的正常结构和功能。展开更多
Objective: To study the reversal effect of neferine on adriamycin (ADM) resistant human breast cancer cell line MCF-7/ADM. Methods: The cytotoxic effect of Nef or ADM was determined by 3-[4, 5-dimethylthiazol-2.-yl], ...Objective: To study the reversal effect of neferine on adriamycin (ADM) resistant human breast cancer cell line MCF-7/ADM. Methods: The cytotoxic effect of Nef or ADM was determined by 3-[4, 5-dimethylthiazol-2.-yl], 5-diphenyl tetraxolium bromid (MTT) assay. Apoptosis and the expression of P-glycoprotein (P-gp) were detected by flow cytometry (FCM). The intracellular ADM concentration was measured by HPLC. Results: Nef at 1, 5, 10 mol/L decreased the IC50 of ADM to MCF-7/ADM from 11.63 g/mL to 4.59, 2.44, 0.27 g/mL respectively. MCF-7/ADM could resist the apoptosis induced by ADM while Nef (1-10 mol/L) could augment ADR-mediated apoptosis. Nef (10 mol/L) increased the accumulation of ADM up to 2.88 fold in MCF-7/ADM but not in sensitive cells MCF-7/S and reduced the expression of P-gp in MCF-7/ADM cells. Conclusion: Nef can circumvent multidrug resistance (MDR) of MCF-7/ADM cells and the mechanism was associated with the increase of intracellular accumulation of ADM and the reduced expression of P-gp in MCF-7/ADM cells.展开更多
AIM:To explore whether antisense blocking of protein kinase C alpha(PKCα)would reverse multi-drug resistance(MDR)in the vincristine(VCR)-resistant human gastric cancer cell line SGC7901/VCR. METHODS:SGC7901/VCR cells...AIM:To explore whether antisense blocking of protein kinase C alpha(PKCα)would reverse multi-drug resistance(MDR)in the vincristine(VCR)-resistant human gastric cancer cell line SGC7901/VCR. METHODS:SGC7901/VCR cells expressing antisense PKCα,SGC7901/VCR/aPKC,were established by transfection with a recombinant plasmid reversely inserted with PKCαcDNA.Empty vector(PCI-neo)transfected cell clones,SGC7901/VCR/neo,served as the control.Western blot method was used to detect PKCαcontent in SGC7901,SGC7901/VCR,SGC7901/ VCR/neo and SGC7901/VCR/aPKC cells,using PKCα-specific antibody.The sensitivity of SGC7901,SGC7901/ VCR,SGC7901/VCR/neo and SGC7901/VCR/aPKC cells to doxorubicin(DOX)in vitro was determined by MTT assay.The uptake of DOX in these cells was detected with fluorescence spectrophotometer.RESULTS:Western blot analysis showed that the PKCαprotein level was about 8.7-fold higher in SGC7901/ VCR cells than that in SGC7901 cells,whereas the protein expression of PKCαwas reduced by 78%in SGC7901/VCR/aPKC cells when compared with the SGC7901/VCR cells.SGC7901/VCR/aPKC cells had a 4.2-fold increase in DOX cytotoxicity,accompanied by a 1.7-fold increase of DOX accumulation in comparison with SGC7901/VCR cells. CONCLUSION:PKCαpositively regulates MDR in SGC7901 cells,and inhibition of PKCαcan partially attenuate MDR in human gastric cancer cells.展开更多
Objective:To find out how to overcome resistance during multiple myeloma(MM) treatment through establishing a multidrug resistant human multiple myeloma cell line and investigating its biological features.Methods:The ...Objective:To find out how to overcome resistance during multiple myeloma(MM) treatment through establishing a multidrug resistant human multiple myeloma cell line and investigating its biological features.Methods:The parent cell line MOLP-2 was exposed to different concentrations of melphalan and a melphalan-resistant cell line MOLP-2/R was identified by continuous stepwise selection.The cell morphology and growth curves were examined.Protein levels of P-gp, MRP and FANCD2 monoubiquitination were checked by Western blotting.The IC50 of melphalan and resistance index(RI) were detected by MTT assay.Results:A melphalan-resistant cell line MOLP-2/R was finally identified.The RI of MOLP-2/R cells to melphalan was 6.03.Besides melphalan it was cross resistant to other chemotherapeutic agents, including ADM, CTX, DDP and VP-16.The multiplication time was postponed(P < 0.05).Studies showed that FANCD2 protein monoubiquitination was enhanced, but the levels of P-gp and MRP expressions in the MOLP-2/R cells were similar with the parent cells.Conclusion:MOLP-2/R cell line may serve as an ideal model for exploring the mechanism of MDR.Over-expression of FANCD2 protein monoubiquitination might contribute to acquired drug resistance in MOLP-2/R cell line.展开更多
文摘Objective: To study the reversal effect of neferine on adriamycin (ADM) resistant human breast cancer cell line MCF-7/ADM. Methods: The cytotoxic effect of Nef or ADM was determined by 3-[4, 5-dimethylthiazol-2.-yl], 5-diphenyl tetraxolium bromid (MTT) assay. Apoptosis and the expression of P-glycoprotein (P-gp) were detected by flow cytometry (FCM). The intracellular ADM concentration was measured by HPLC. Results: Nef at 1, 5, 10 mol/L decreased the IC50 of ADM to MCF-7/ADM from 11.63 g/mL to 4.59, 2.44, 0.27 g/mL respectively. MCF-7/ADM could resist the apoptosis induced by ADM while Nef (1-10 mol/L) could augment ADR-mediated apoptosis. Nef (10 mol/L) increased the accumulation of ADM up to 2.88 fold in MCF-7/ADM but not in sensitive cells MCF-7/S and reduced the expression of P-gp in MCF-7/ADM cells. Conclusion: Nef can circumvent multidrug resistance (MDR) of MCF-7/ADM cells and the mechanism was associated with the increase of intracellular accumulation of ADM and the reduced expression of P-gp in MCF-7/ADM cells.
基金Supported by The Research Fund of the Educational Departmentof Zhejiang Provincial Government,No.20070609the Research Fund of Jiaxing Science and Technology Bureau,No.2007AY2033
文摘AIM:To explore whether antisense blocking of protein kinase C alpha(PKCα)would reverse multi-drug resistance(MDR)in the vincristine(VCR)-resistant human gastric cancer cell line SGC7901/VCR. METHODS:SGC7901/VCR cells expressing antisense PKCα,SGC7901/VCR/aPKC,were established by transfection with a recombinant plasmid reversely inserted with PKCαcDNA.Empty vector(PCI-neo)transfected cell clones,SGC7901/VCR/neo,served as the control.Western blot method was used to detect PKCαcontent in SGC7901,SGC7901/VCR,SGC7901/ VCR/neo and SGC7901/VCR/aPKC cells,using PKCα-specific antibody.The sensitivity of SGC7901,SGC7901/ VCR,SGC7901/VCR/neo and SGC7901/VCR/aPKC cells to doxorubicin(DOX)in vitro was determined by MTT assay.The uptake of DOX in these cells was detected with fluorescence spectrophotometer.RESULTS:Western blot analysis showed that the PKCαprotein level was about 8.7-fold higher in SGC7901/ VCR cells than that in SGC7901 cells,whereas the protein expression of PKCαwas reduced by 78%in SGC7901/VCR/aPKC cells when compared with the SGC7901/VCR cells.SGC7901/VCR/aPKC cells had a 4.2-fold increase in DOX cytotoxicity,accompanied by a 1.7-fold increase of DOX accumulation in comparison with SGC7901/VCR cells. CONCLUSION:PKCαpositively regulates MDR in SGC7901 cells,and inhibition of PKCαcan partially attenuate MDR in human gastric cancer cells.
文摘Objective:To find out how to overcome resistance during multiple myeloma(MM) treatment through establishing a multidrug resistant human multiple myeloma cell line and investigating its biological features.Methods:The parent cell line MOLP-2 was exposed to different concentrations of melphalan and a melphalan-resistant cell line MOLP-2/R was identified by continuous stepwise selection.The cell morphology and growth curves were examined.Protein levels of P-gp, MRP and FANCD2 monoubiquitination were checked by Western blotting.The IC50 of melphalan and resistance index(RI) were detected by MTT assay.Results:A melphalan-resistant cell line MOLP-2/R was finally identified.The RI of MOLP-2/R cells to melphalan was 6.03.Besides melphalan it was cross resistant to other chemotherapeutic agents, including ADM, CTX, DDP and VP-16.The multiplication time was postponed(P < 0.05).Studies showed that FANCD2 protein monoubiquitination was enhanced, but the levels of P-gp and MRP expressions in the MOLP-2/R cells were similar with the parent cells.Conclusion:MOLP-2/R cell line may serve as an ideal model for exploring the mechanism of MDR.Over-expression of FANCD2 protein monoubiquitination might contribute to acquired drug resistance in MOLP-2/R cell line.
