MiR-137's Tumor Suppression on Prolactinomas by Targeting MITF and Modulating Wnt Signaling Pathway.

MiR-137's Tumor Suppression on Prolactinomas by Targeting MITF and Modulating Wnt Signaling Pathway.

J Clin Endocrinol Metab. 2019 12 01;104(12):6391-6402

Authors: Lei C, Jing G, Jichao W, Xiaohui L, Fang Q, Hua G, Yazhou M, Zhang Y

Abstract CONTEXT: Prolactinomas are the most common functional pituitary adenomas; the aggressive tumors still present challenge to clinicians. Aberrant expression of miRNAs has been functionally associated with prolactinomas. OBJECTIVE: Here we explored the role of miR-137 on the proliferation, invasion, and apoptosis of prolactinomas and its possible mechanism. RESULTS: Low expression of miR-137 was correlated with the invasive behavior of human prolactinomas and predicted high recurrence. MiR-137 inhibited cell proliferation, invasion, and survivals of MMQ and GH3 cells and reduced tumor volume in F344 rat prolactinomas. The luciferase reporter assay confirmed that microphthalmia-associated transcription factor (MITF) was the direct target of miR-137. In addition, miR-137 mimics could inhibit MITF expression in vivo and in vitro. Upregulation of MITF expression promoted cell proliferation, invasion, and survivals and reversed the antitumor effect of miR-137 in vivo and in vitro. Furthermore, miR-137 could also upregulate wnt-inhibitory factor-1 and inhibit nuclear translocation of β-catenin. Upregulation of wnt-inhibitory factor-1 with decitabine can enhance the inhibition on cell proliferation of miR-137. A glycogen synthase kinase-3 inhibitor, SB 216763, promoted cell proliferation by upregulation of total/cytoplasmic/nuclear β-catenin and reversed tumor suppression of miR-137 mimics. CONCLUSIONS: Our data suggest that miR-137 possesses a tumor invasive suppressor function with a prognostic value in prolactinomas by targeting MITF and modulating Wnt-β-catenin signaling pathway.

PMID: 31162548 [PubMed - indexed for MEDLINE]