miR-221/222 promote tumor growth and suppress apoptosis by targeting lncRNA GAS5 in breast cancer.
Biosci Rep 2019;
39:BSR20181859. [PMID:
30538172 PMCID:
PMC6331665 DOI:
10.1042/bsr20181859]
[Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/03/2018] [Accepted: 12/07/2018] [Indexed: 01/26/2023] Open
Abstract
MicroRNAs (miRNAs) are 21-23-nucleotide, short, non-coding RNAs that play important roles in virtually all biological pathways in mammals and other multicellular organisms. The association of miR-221 and miR-222 (miR-221/222) for breast cancer is critical, but their detailed roles in its development and progression remain unclear. In the present study, we found that miR-221/222 were consistently up-regulated in breast cancer tissues. We then investigated the molecular mechanisms by which miR-221/222 contributed to breast cancer and identified growth arrest-specific transcript 5 (GAS5) as a direct target gene of miR-221/222. In contrast with the up-regulated expression levels of miR-221/222, GAS5 levels were significantly down-regulated and negatively correlated with miR-221/222 in breast cancer tissues. In addition, we showed that miR-221/222 inhibitors increased cellular apoptosis, miR-221/222 mimics decreased the cell apoptosis in breast cancer cells, and restoration of GAS5 expression attenuated the anti-apoptotic effects of miR-221/222 in breast cancer cells, indicating that GAS5 was a direct mediator of miR-221/222 function. Finally, we showed that miR-221/222 suppressed GAS5 expression significantly and enhanced tumor growth in a mouse model of breast cancer xenografts. The present study highlighted the important role of miR-221/222 as oncomiRs in breast cancer, which inhibited GAS5 translation. These findings may provide a new perspective for the molecular mechanism of breast carcinogenesis and provide a novel approach to the treatment of breast cancer.
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