Increased chemotherapy sensitivity on adriamycin resistance cells of breast cancer by up-regulated EGR-1

OBJECTIVE:To explore the chemotherapy sensitivity of transcription factor EGR-1 on the adriamycin resistance cells of breast cancer.METHODS:The expression type human EGR-1 plasmid was transfected into MCF-7/Adr cells to enhance the expression of EGR-1.Then the double stain with Annexin-V-FITC/PI was performed to detect cell apoptosis by flow cytometry(FCM).MCF-7/Adr cell viability was determined via MTT method.EGR-1 mRNA were assessed by RT-PCR.Caspase-3 and P-gp proteins were detected by Western blot.RESULTS:After being stable transfected with pcDNA3.1/EGR-1 plasmid,a significant difference in the apoptosis efficiency was observed between the pcDNA3.1/EGR-1〔(41.43±2.34)%〕,pcDNA3.1 empty vector and the negative control group MCF-7/Adr cells(P=0.011).In the presence of 100 μg/mL concentrations of adriamycin,the viability of MCF-7/Adr cells was significantly decreased after the transfection only 35%(P=0.037).Compared with the pcDNA3.1 empty vector and negative control groups,there was a significant difference in expression of EGR-1 mRNA(79.4±1.8)%(P=0.008).The expression of Caspase-3 protein of the pcDNA3.1/EGR-1 transfected group in MCF-7/Adr cells was significantly increased(58.7±2.1)%,and the expression of P-gp protein was significantly decreased(34.2±2.1)%(P0.05).CONCLUSIONS:The up-expression of EGR-1 can effectively reverse adriamycin resistance in MCF-7/Adr cells.It may be related to the up-regulated EGR-1 increasing Caspase-3 level and inducing cell apoptosis.