Network-guided genetic screening for metastasis-related microRNA-200c in breast cancer

To screen for the gene network regulated by breast cancer metastasis-related miR- 200c (microRNA-200c) using bioinformatics means. Methods: The miRNAs differentially expressed in 12 types of breast cell lines were screened out using Affymetrix® miRNA Array. Lipofectamine was supplied in the transfection of miR-200c mimic into four breast cancer cell lines with high-metastatic capability (BT549, HS578T, MDA-MB-231 and SUM159PT cells). The genes differentially expressed in these four breast cancer cell lines were screened through mRNA expression profiling. The signalling pathways and the gene network regulated by miR-200c were screened using MAS (Molecule Annotation System) (CapitalBio Molecule Annotation System). Results: Nine miRNAs were differentially expressed among 12 types of breast cell lines (P < 0.01, fold change ≥20 or ≤-20), and the expression of miR-200c was decreased most significantly in breast cancer cell lines of high metastatic potential. There were 33 co-upregulated genes and 13 codownregulated genes shared through the four breast cancer cell lines of high metastatic potential after transfection with miR-200c mimic. The results of real-time fluorescence quantitative PCR and Western blotting confirmed that the expressions of ZEB1 (zinc finger E-box binding homeobox 1) mRNA and protein were decreased in four transfected cell lines. The bioinformatics analysis using MAS suggested that the common signalling pathways related to the genes differentially expressed in breast cancer cells transfected with miR-200c mimic included pathways olfactory transduction, cytokine-cytokine receptor interaction, cell adhesion molecules, etc . The different signalling pathways could be in interconnection with each other through co-regulated genes, and co-regulated genes had a close interrelationship within a specific pathway. Conclusion: Based on high-throughput screening using Biochip technology, the bioinformatics analysis is able to demonstrate the gene network regulated by miR-200c and provide an explicit direction for further mechanism research on miR-200c.