Low expression of microRNA-125b enhances the expression of STAT3 and contributes to cholesteatoma growth

Abstract

Introduction: MicroRNA-125b has been found to be down-regulated in many types of malignant tumours and diseases with excessive proliferation of keratinocytes, such as cutaneous squamous cell carcinoma and psoriasis. Cholesteatoma, which is mainly composed of keratinocytes, also has characteristics of abnormal proliferation similar to a malignant tumour. However, the expression and regulatory mechanisms of miR-125b and its downstream genes in cholesteatoma have not been clarified. Material and methods: Real time fluorescence quantitative PCR was applied to detect the expression of miR-125b in the cholesteatoma and corresponding retroauricular skin. Immunohistochemical staining and western blot were used to detect signal transducers and activators of transcription 3 (STAT3) and the downstream gene cyclinD1, survivin, and vascular endothelial growth factor (VEGF) in the cholesteatoma and corresponding retroauricular skin. The targeted regulatory relationship between miR-125b and STAT3 was confirmed by dual luciferase reporter assay. Proliferation and apoptosis of transfected HaCaT cells were detected by MTS, cell cycle, and apoptosis assays. Results: We observed down-regulation of miR-125b and up-regulation of STAT3, cyclinD1, survivin, and VEGF in cholesteatoma tissues. STAT3 was a direct target gene of miR-125b. Inhibition of miR-125b enhanced STAT3 and its downstream genes expression, promoted HaCaT cell proliferation, and inhibited apoptosis. Conclusions: The results of this study demonstrate that miR-125b can influence the growth of cholesteatoma by targeting STAT3 and its downstream genes, including cyclinD1, survivin, and VEGF, thus providing an opportunity to establish new medical therapy strategies and facilitating further study of the pathogenesis of cholesteatoma.

Expression and Regulatory Mechanisms of MicroRNA in Cholesteatoma: A Systematic Review

“…Zang et al [44] observed downregulation of miR-125b and upregulation of STAT3, cyclin D1, survivin, and VEGF in cholesteatoma tissues, which is consistent with the results of previous studies [17,57,102,103]. These reports imply that the inhibition of miR-125b expression in cholesteatoma may contribute to high proliferation and low apoptosis through an increased expression of STAT3, which could be used as a potential therapeutic target for intratympanic pharmacotherapy of cholesteatoma [17].…”

“…In total, 118 articles were retrieved through the database search. After applying the search strategy described above, a total of 18 articles were identified that met all inclusion criteria [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. A flow diagram of the detailed study selection process is presented in Figure 1.…”

“…All included studies used cholesteatoma tissues for analysis. Additionally, the majority of studies included in vitro experiments on cell lines [30,32,[34][35][36][37][38][39][42][43][44]46,47]. In the Zheng study [46], a mouse model was also used for in vivo testing.…”

“…Retroauricular skin has been used as a control material in many of the included studies [31,33,[35][36][37][38][40][41][42][43][44][45]47]. There are reports that the selection of control group material in cholesteatoma studies can be important for the outcome of the studies, with deep meatal skin specimens being more similar in protein profile to cholesteatoma than retroauricular skin [165,166].…”