Deletion of <i>HNF1A-AS1</i> Suppresses the Malignant Phenotypes of Breast Cancer Cells <i>In Vitro</i> and <i>In Vivo</i> Through Targeting <i>miRNA-20a-5p/TRIM32</i> Axis

Abstract

<b><i>Background:</i></b> Hepatocyte nuclear factor 1 homeobox A-antisense RNA 1 (<i>HNF1A-AS1</i>) is a long noncoding RNA and controls human tumor development and progression. However, its expression and role in breast cancer, the most overwhelmingly occurring malignancy in women globally, remain poorly illuminated. <b><i>Materials and Methods:</i></b> Expression of <i>HNF1A-AS1</i>, <i>miRNA</i> (<i>miR</i>)-<i>20a-5p</i>, and tripartite motif containing 32 (<i>TRIM32</i>) was detected using quantitative real-time polymerase chain reaction and Western blotting. Cell proliferation, apoptosis, migration, and invasion were measured by cellTiter 96 AQueous one solution cell proliferation assay kit, flow cytometry, and transwell assays, respectively. Epithelial-mesenchymal transition (EMT) was evaluated by Western blotting, analyzing E-cadherin, N-cadherin, and vimentin expression. Mice xenograft model was generated to investigate tumor growth <i>in vivo</i>. The target binding among <i>miR-20a-5p</i>, <i>HNF1A-AS1</i>, and <i>TRIM32</i> was confirmed by dual-luciferase reporter assay. <b><i>Results:</i></b> Expression of <i>HNF1A-AS1</i> and <i>TRIM32</i> was upregulated and <i>miR-20a-5p</i> was downregulated in breast cancer tumors and cell lines. Deletion of <i>HNF1A-AS1</i> induced cell apoptosis rate, but suppressed cell proliferation, EMT, migration, and invasion in MDA-MB-231 and MCF-7 cells. Furthermore, <i>HNF1A-AS1</i> downregulation impeded tumor growth <i>in vivo</i>. Interestingly, <i>miR-20a-5p</i> overexpression elicited the similar suppressive effects in MDA-MB-231 and MCF-7 cells, which was partially reversed by <i>TRIM32</i> upregulation; besides, <i>miR-20a-5p</i> silencing could abolish the antitumor role of <i>HNF1A-AS1</i> deletion. Notably, <i>HNF1A-AS1</i> positively modulated <i>TRIM32</i> expression through acting as a molecular "sponge" for <i>miR-20a-5p</i>. <b><i>Conclusions:</i></b> Knockdown of <i>HNF1A-AS1</i> suppressed breast carcinogenesis presumably through targeting <i>miR-20a-5p</i>/<i>TRIM32</i> axis, suggesting that <i>HNF1A-AS1</i> might be a promising therapy target for breast cancer.