Long Non-Coding RNA A2M-AS1 Promotes Breast Cancer Progression by Sponging microRNA- 146b to Upregulate MUC19

Background: Long non-coding RNA (lncRNA) A2M-AS1 has been indicated to be augmented in breast cancer (BC), with its specific function undetermined. Therefore, this study is designed to investigate the mechanism of lncRNA A2M-AS1 in BC. Methods: The expression of A2M-AS1, microRNA (miR)-146b, and MUC19 in BC tissues and cells was measured. Then, the interaction among A2M-AS1, miR-146b, and MUC19 was detected. After A2M-AS1, miR-146b, and MUC19 expression were altered in BC cells, cell proliferation, invasion, and apoptosis were detected, and the protein levels of Hippo-related proteins (YAP and p-YAP) were evaluated. Tumor growth assay was also performed to validate the effects of A2M-AS1 and miR-146b in vivo. Results: A2M-AS1 and MUC19 were highly expressed in BC, while miR-146b was poorly expressed. A2M-AS1 acts as a molecular sponge for miR-146b, which targeted and negatively modulated MUC19. A2M-AS1 accelerated BC cell proliferation, invasion, and colony formation and suppressed apoptosis via the miR-146b/MUC19/Hippo axis, which was confirmed in vivo. Conclusion: Taken above together, an oncogenic role for A2M-AS1 in BC was elicited by acting as a miR-146b sponge to promote MUC19 expression. The findings will present some cues for a further approach to BC.