miR-30a-5p Inhibits Epithelial-to-Mesenchymal Transition by Targeting CDK6 in Nasal Polyps

Background: Epithelial-to-Mesenchymal Transition (EMT) is considered as a crucial event in disease development and dysregulation of microRNAs (miRNAs) is involved in the regulation of EMT in various human diseases. Emerging evidences congregated over the years have demonstrated that miR-30a-5p was decreased in diseases and its overexpression inhibited the process of diseases via attenuating EMT. Although aberrant expression of miRNAs and occurrence of EMT were previously reported in Nasal Polyps (NPs), the role of miR-30a-5p in EMT of NPs is still remains unclear.

Objective: The purpose of our present study was to explore the expression and potential function of miR-30a-5p in EMT of NPs.

Methods: The expression of miR-30a-5p and mRNA expression level were detected by quantitative real-time PCR (qRT-PCR) in transforming growth factor β1 (TGF-β1) - induced EMT model and NPs patients. Western Blot (WB) and immunohistochemistry (IHC) were performed to evaluate the protein expression level of EMT markers. The cells mobility was assessed by Wound-Healing assay. Luciferase reporter assay was utilized to verify the relationship between Cyclin-dependent kinase 6 (CDK6) and miR-30a-5p.

Results: Firstly, we observed that miR-30a-5p was down-regulated notably, accompanying with the alteration of EMT markers expression in NPs tissues and EMT model induced by TGF-β1 in primary Human Nasal Epithelial Cells (pHNECs) and A549 cells in vitro. Moreover, the functional assays demonstrated that overexpression of miR-30a-5p significantly inhibited EMT and cells mobility. Subsequently, CDK6 was validated as a direct target of miR-30a-5p. Finally, we performed the rescue experiments indicating that overexpression of CDK6 eliminated the suppressive effects of miR-30a-5p in TGF-β1-induced EMT in pHNECs and A549 cells.

Conclusion: Taken together, our results suggested that EMT was involved in NPs, and overexpression of miR-30a-5p could attenuate EMT via repressing the expression of the CDK6 in pHNECs and A549 cells.