title: Adenovirus-mediated p53 gene therapy reverses resistance of breast cancer cells to adriamycin.
abstract: The aim of this study was to determine whether adenovirus-mediated p53 gene (Ad-p53) transfection can enhance adriamycin cytotoxicity and reverse adriamycin resistance in human breast cancer cells and explore its effect on the expression of MDR1 gene and permeability-glycoprotein (P-gp). Human breast cancer cell lines, MCF-7 and MCF-7/ADR, were used in in-vitro studies. After infection with Ad-p53, the cytotoxicity of adriamycin was evaluated using the Cell Counting Kit-8 assay. The expression of MDR1 mRNA was detected by quantitative real-time PCR. The expression of P-gp was analyzed using western blotting. In in-vivo studies, MCF-7/ADR tumor cells were inoculated subcutaneously in athymic nude mice. After 14 days of inoculation, tumor size was measured. Apoptosis and expression of P-gp in the tumor tissue were analyzed by fluorescence activated cell sorting and western blotting. After transfection with a multiplicity of infection of 50 for Ad-p53, chemosensitivity of MCF-7/ADR cells increased by 18.1 times (P=0.001), and 50% inhibitory concentration (IC50) of adriamycin decreased from 4.54 ± 0.91 to 0.26 ± 0.11 mg/l. Real-time PCR showed that MDR1 mRNA decreased from 1.32 to 0.85 (P=0.001). Western blotting analysis showed that P-gp also decreased. In in-vivo studies, Ad-p53 combined with adriamycin dramatically inhibited the growth of subcutaneous xenograft of MCF-7/ADR. The fluorescence activated cell sorting assay showed that there were more apoptotic cells in tumor tissues treated with Ad-p53 and adriamycin. The expression of P-gp was significantly decreased in tumor tissues. This study suggests that Ad-p53 can reverse MCF-7/MDR cell resistance to adriamycin. The reversal effect was associated with inhibition of P-gp expression and induction of apoptosis.
authors.affiliation: Breast Center of Military General Hospital of Beijing PLA, China. qixiaot@yeah.net
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Qi
authors.forename: Zhikun
authors.initials: Z
authors.lastname: Chang
authors.forename: Jin
authors.initials: J
authors.lastname: Song
authors.forename: Gui
authors.initials: G
authors.lastname: Gao
authors.forename: Zheng
authors.initials: Z
authors.lastname: Shen
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics; D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000627:therapeutic use*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004317:Doxorubicin / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005260:Female; D005434:Flow Cytometry; D016158:Genes, p53 / Q000235:genetics*; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014183:Transplantation, Heterologous
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D012333:RNA, Messenger; D004317:Doxorubicin