Advances in Cancer Biology - Metastasis (Oct 2021)
miR-221 regulates proliferation, invasion, apoptosis and progression of prostate cancer cells by modulating E-cadherin/Wnt/β catenin axis
Abstract
MicroRNA-221 (miR-221) is aberrantly expressed in various tumours including prostate carcinoma and can act as either tumour suppressor or oncogene depending on the tumour system and stage. Epithelial-mesenchymal transition (EMT) is a plastic transition in tumour progression characterized by decreased expression of epithelial markers and increased expression of mesenchymal markers and has been known to play a critical role in promoting metastases. In this study, we have demonstrated the functional role of miR-221 in regulating epithelial-mesenchymal transition in prostate cancer. Expression of miR-221 was found to be downregulated in androgen-independent prostate cancer cells and was found to be inversely correlated with EMT. Ectopic expression of miR-221 potentially inhibited invasion and migration of androgen-independent prostate cancers cells and inhibition of miR-221 expression rescued the anti-invasive effects of miR-221. Flow cytometric analysis further revealed that miR-221 could induce cell cycle arrest with simultaneous induction of apoptosis. Additionally, transfection with miR-221 mimic upregulated negative regulators of Wnt/β catenin pathway such as GSK-3β thereby inhibiting it and downregulated mesenchymal markers viz., N-cadherin and Vimentin with simultaneous upregulation of epithelial marker E-cadherin as revealed by real-time PCR and Western blot analysis. A study using xenograft model further confirmed the anti-tumorigenic and anti-metastatic role of miR-221 in prostate cancer. We believe that his study is the first report documenting the miR-221- Wnt/β catenin signaling-EMT regulatory circuit in prostate cancer.
