ABSTRACT
The microRNA-200 (miR-200) family is associated with tumor metastasis and poor patient prognosis. We found that miR-200c/141 cluster overexpression upregulated SerpinB2 in the MDA-MB-231 triple-negative (TN) breast cancer cell line. We observed transcription factor (c-Jun, c-Fos, and FosB) upregulation, nuclear localization of c-Jun, and increased SerpinB2 promoter-directed chloramphenicol acetyltransferase activity in miR-200c/141 cluster-overexpressing cells relative to controls. Additionally, miR-124a and miR-26b, which directly target SepinB2, were downregulated compared to controls. In mouse xenograft models, miR-200c/141 cluster overexpression promoted lymph node and lung metastasis, and siRNA-mediated SerpinB2 knockdown decreased lung metastasis, suggesting that SerpinB2 mediates miR-200c/141-induced lung metastasis. We also explored the clinical significance of SerpinB2 protein status through analysis of primary breast tumor samples and The Cancer Genome Atlas (TCGA) data. High SerpinB2 levels were associated with reduced survival and increased lymph node metastasis in breast cancer patients. SerpinB2 was overexpressed in the TN breast cancer subtype as compared to the luminal subtype. The present study demonstrates that SerpinB2 promotes miR-200c/141 cluster overexpression-induced breast cancer cell metastasis, and SerpinB2 overexpression correlates with increased metastatic potential and unfavorable outcomes in breast cancer patients. SerpinB2 may be a useful biomarker for assessing metastasis risk in breast cancer patients.
Subject(s)
Lung Neoplasms/secondary , MicroRNAs/genetics , Plasminogen Activator Inhibitor 2/genetics , Triple Negative Breast Neoplasms/pathology , Animals , Cell Line, Tumor , Epithelial-Mesenchymal Transition , Female , Gene Expression Regulation, Neoplastic , Humans , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Lymphatic Metastasis , Mice , Multigene Family , Neoplasm Metastasis , Neoplasm Staging , Neoplasm Transplantation , Survival Analysis , Triple Negative Breast Neoplasms/genetics , Up-RegulationABSTRACT
To explore the role of ErbB-mediated signaling in cardiogenesis of ES cells, we examined the expression of ErbB receptors as well as effects of a ligand and inhibitors using Nkx2.5GFP ES cells, in which the GFP gene was knocked-in to the Nkx2.5 locus to monitor cardiac differentiation. Although all ErbB receptors were expressed in developing embryoid bodies, expression of ErbB4 was almost exclusively found in differentiated cardiomyocytes. Heregulin beta1, a ligand of ErbB receptors, enhanced the generation of Nkx2.5/GFP(+) cardiomyocytes in embryoid bodies, while AG1478 and PD153035, inhibitors of ErbBs, drastically blocked the generation of Nkx2.5/GFP(+) cardiomyocytes. These results suggest that the signaling pathway mediated by ErbBs is important in the induction and differentiation of cardiomyocytes from ES cells.