The Change Of Gene Expression Profiles In Breast Cancer Cell Lines Treated By Anticancer Drugs

BACKGROUND: Chemoresistance is a major clinical problem in the treatment of human malignancy. Because of heterogeneity , breast tumors are diverse in their responsiveness to chemotherapy. It's very necessary to establish a method and select indicators for predicting efficacy of anticancer drugs for individual patients. OBJECTIVE: To investigate the change of gene expression profiles in breast cancer cell lines treated by anticancer drugs.METHODS: The drug sensitivities of MCF-7 and MDA-MB-231 cell lines to ADM (adriamycin), 5-FU(5-fluorouracil), MTX(methotrexate) and drug combination AF(ADM+5-FU) and MF(MTX+5-FU) were examined by MTT assay. Flow cytometry (Annexin-V and PI) was used to detect apoptosis and cell cycle distribution in breast cancer cell lines administered with anticancer drugs.Then a cDNA microarray representing 14,000 genes was used to analyze expression profiles of breast cancer cell lines pre- and post-chemotherapy.RESULTS: The differences of chemosensitivity to each drug were showed between MCF-7 and MDA-MB-231.Comparison of the gene expresison proflies of two cell lines , a series of genes expressed coincidentally in both cell lines were selected for each drug treatment.They play important role in multiple process including cytoskeleton, signal conduction, cell proliferation/differentiation , regulation of cell cycle, transcription and translation of gene and metabolism of cell. CONCLUSIONS: These results demonstrate that the process of a anticancer drug killing tumor cells is very complicated involving many gene upregulated or downregulated expresison .As a new approach, cDNA microarray is feasible to genomewide exploration of gene expression patterns correlated to chemosensitivity.