Metformin-repressed miR-381-YAP-snail axis activity disrupts NSCLC growth and metastasis
Authors: Guoming Su
Juanjuan Dai
Yan Wu
Kaikai Gong
Jing Du
Lijuan Yang
Dan Jin
Jiwei Guo
Weiwei Chen
Xiaohong Wang
Shuang Miao
Xuelin Li
Journal: Journal of Experimental & Clinical Cancer Research (2020)
Discipline: CLINICAL MEDICINE
Keywords: EMT; Metformin; NSCLC; Snail; YAP
Affiliations: Clinical Medicine Laboratory, Binzhou Medical University Hospital, Binzhou, 256603, People's Republic of China., Cancer research institute, Binzhou Medical University Hospital, Binzhou, 256603, People's Republic of China. ., Cancer research institute, Binzhou Medical University Hospital, Binzhou, 256603, People's Republic of China., Department of Thyroid and Breast Surgery, Binzhou Medical University Hospital, Binzhou, 256603, People's Republic of China., Department of Nursing, Binzhou Polytechnic University, Binzhou, 256603, People's Republic of China.

Abstract:  Background: Recent evidence indicates that metformin inhibits mammalian cancer growth and metastasis through the regulation of microRNAs. Metformin regulates miR-381 stability, which plays a vital role in tumor progression. Moreover, increased YAP expression and activity induce non-small cell lung cancer (NSCLC) tumor growth and metastasis. However, the molecular mechanism underpinning how metformin-induced upregulation of miR-381 directly targets YAP or its interactions with the epithelial-mesenchymal transition (EMT) marker protein Snail in NSCLC is still unknown. Methods: Levels of RNA and protein were analyzed using qPCR, western blotting and immunofluorescence staining. Cellular proliferation was detected using a CCK8 assay. Cell migration and invasion were analyzed using wound healing and transwell assays. Promoter activity and transcription were investigated using the luciferase reporter assay. Chromatin immunoprecipitation was used to detect the binding of YAP to the promoter of Snail. The interaction between miR-381 and the 3'UTR of YAP mRNA was analyzed using the MS2 expression system and co-immunoprecipitation with biotin. Results: We observed that miR-381 expression is negatively correlated with YAP expression and plays an opposite role to YAP in the regulation of cellular proliferation, invasion, migration, and EMT of NSCLC cells. The miR-381 function as a tumor suppressor was significantly downregulated in lung cancer tissue specimens and cell lines, which decreased the expression of its direct target YAP. In addition, metformin decreased cell growth, migration, invasion, and EMT via up-regulation of miR-381. Moreover, YAP, which functions as a co-transcription factor, enhanced NSCLC progression and metastasis by upregulation of Snail. Snail knockdown downregulated the mesenchymal marker vimentin and upregulated the epithelial marker E-cadherin in lung cancer cells. Furthermore, miR-381, YAP, and Snail constitute the miR-381-YAP-Snail signal axis, which is repressed by metformin, and enhances cancer cell invasiveness by directly regulating EMT. Conclusions: Metformin-induced repression of miR-381-YAP-Snail axis activity disrupts NSCLC growth and metastasis. Thus, we believe that the miR-381-YAP-Snail signal axis may be a suitable diagnostic marker and a potential therapeutic target for lung cancer. 

Retracted: No

PubPeer comments:
 Images in Figure 4C and 4D seem to also appear in Figure 4e of August 2018 Journal of Cellular Physiology DOI: 10.1002 jcp.27094, discussed here: https: pubpeer.com publications A01DF7A476CFFE54ED07B5B3B16C5B#2. I did not see any overlap in authorship or institutional affiliation. I was unable to find any resemblance between the corresponding authors names and non-institutional email addresses. *** ![file] ,