J Cancer 2016; 7(12):1653-1662. doi:10.7150/jca.14762 This issue

Research Paper

MicroRNA-34c Suppresses Breast Cancer Migration and Invasion by Targeting GIT1

Wei-Yang Tao1, 2, Chun-Yang Wang2, 3, Yong-Hui Sun1, Yong-Hui Su1, Da Pang1, Guo-Qiang Zhang1✉

1. Department of Breast Surgery, Harbin Medical University Cancer Hospital, Harbin, China;
2. Key Laboratory of Cardiovascular Medicine Research (Harbin Medical University), Ministry of Education, Harbin, China;
3. Department of Urology, The First Affiliated Hospital of Harbin Medical University, Harbin, China.

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Tao WY, Wang CY, Sun YH, Su YH, Pang D, Zhang GQ. MicroRNA-34c Suppresses Breast Cancer Migration and Invasion by Targeting GIT1. J Cancer 2016; 7(12):1653-1662. doi:10.7150/jca.14762. Available from https://www.jcancer.org/v07p1653.htm

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Abnormal expression of microRNAs plays important role in tumor metastasis. Migration and invasion of cancer cells accord for the metastasis and deterioration of breast cancer. However, the regulatory role of microRNAs in the invasion and migration of breast cancer cells has not completely understood yet. Here we found that microRNA-34c (miR-34c) was significantly downregulated in metastatic tissue of breast cancer. In vitro study showed that miR-34c negatively regulated GIT1 protein expression by binding to the 3'UTR of GIT1 mRNA. Consistently, GIT1 protein expression was found upregulated significantly in metastatic breast cancer. Moreover, miR-34c overexpression suppressed the expression of GIT1 protein, and this effect was restored by AMO-miR-34c in breast cancer cells. Overexpression of miR-34c suppressed cell migration and invasion in both MCF-7 and MDA-MD-231 breast cancer cells. Furthermore, knockdown of endogenous GIT1 expression reduced the migration and invasion of both two breast cancer cells. Collectively, miR-34c downregulation in breast cancer cells resulted in the upregulation of GIT1, which in turn enhanced the migration and invasion of breast cancer. This study highlights molecular mechanism of migration and invasion of breast cancer cells.

Keywords: miR-34c, breast cancer, GIT1, metastasis.