Regulations of miR-183-5p and Snail-Mediated Shikonin-Reduced Epithelial-Mesenchymal Transition in Cervical Cancer Cells

Abstract

Background

Shikonin, the main ingredient of Lithospermum erythrorhizon, has been reported to have antitumor effects via multiple targets and signaling pathways. However, the detailed mechanism underlying the effects in cervical cancer still remained unknown.

Methods

MTT, wound-healing, transwell assays and flow cytometry experiments were used to measure cell growth, migration, invasion, and cell cycle analysis. Western blot was used to examine protein levels of Snail, Vimentin and E-cadherin. The expression level of miR-183-5p was measured via qRT-PCR. The E-cadherin promoter activity was detected via Secrete-PairTM Dual Luminescence Assay Kit. The transient transfection experiments were used for silencing of E-cadherin and overexpression of Snail genes. Tumor xenograft and bioluminescent imaging experiments were carried out to confirm the in vitro findings.

Results

We showed that shikonin inhibited cell viability, migration and invasion, and induced cell cycle arrest in a dose-dependent manner in cervical cancer Hela and C33a cells. Mechanistically, we found that shikonin increased miR-183-5p expression and inhibited expression of transcription factor Snail protein. The mimics of miR-183-5p reduced, while the inhibitors of miR-183-5p reversed shikonin-inhibited Snail protein expression. In addition, shikonin decreased Vimentin, increased E-cadherin protein expressions and E-cadherin promoter activity, the latter was reversed in cells transfected with exogenous Snail overexpression vectors. Moreover, silencing of E-cadherin significantly abolished shikonin-inhibited cervical cancer cell growth. Similar findings were also observed in vivo using one xenograft mouse model.

Conclusion

Our results show that shikonin inhibits EMT through inhibition of Snail and stimulation of miR-183-5p expressions, which resulted in induction of E-cadherin expression. Thus, blockade of EMT could be a novel mechanism underlying the anti-cervical cancer effects of shikonin.

Keywords:

• shikonin
• EMT
• cervical cancer
• miR-183-5p
• Snail
• E-cadherin

Acknowledgments

This work was supported in part by the grants from the National Natural Scientific Foundation of China (Nos. 81473716, 81703551, and 81871863) and the Major Program of National Natural Science Foundation of Guangdong (No. 2018B030311061).

Author Contributions

All authors made substantial contributions to conception and design, acquisition of data or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests.