Screening the differential expression of adriamycin-resistance related genes of breast cancer by cDNA microarray

Objective: To study the differential gene expression of adriamycin-resistance of breast cancer cell line MCF-7/ADR as compared with its parent cell MCF-7 and screen the related genes.

Methods: The in vitro inhibitory rate of MCF-7/ADR and MCF-7 cell lines to ADM (adriamycin) was examined by MIT assay. Then a cDNA microarray representing 14,755 genes was used to analyze the expression profiles of these two breast cancer cell lines.

Results: The inhibitory rate of MCF-7/ ADR to ADM was lower than that of MCF-7(P <0.05)and the drug resistance to ADR of MCF-7/ADR was stronger than that of MCF-7. There were 2374 differential expression genes in MCF-7/adr and MCF-7 cell lines, of which 1099 genes upregulated with 99 genes 10-fold upregulated and 1275 genes downregulated with 71 genes 10-fold downregulated. The important upregulated genes were Bcl-2, GSTP1, c-myc, MMP-1 and NNMT while those downregulated ones p53, p21, p27 and CYPIA1.

Conclusions: Drug resistance of breast cancer is a complicated process involving the expression of many upregulated or downregulated genes. The application of gene chip in screening drug-resistant genes may be a new approach for selecting the optimal chemotherapeutic regimens. [Key words]