Mir-124 Attenuates STAT3-Mediated TH17 Differentiation in Colitis-Driven Colon Cancer

Front Oncol. 2020 Dec 17:10:570128. doi: 10.3389/fonc.2020.570128. eCollection 2020.

Abstract

Background: Inflammation often induces regeneration to repair the tissue damage. However, chronic inflammation can transform temporary hyperplasia into a fertile ground for tumorigenesis. Here, we demonstrate that the miR-124 acts as a safeguard to inhibit the pro-inflammatory production and reparative regeneration.

Methods: The expression levels of miR-124 and IL-17, IFN-γ were detected by qRT-PCR. TH17 or TH1 cells were detected by flow cytometer, respectively. The binding of STAT3 to the promoter region of IL-17 gene was analyzed by Chip assay. miR-124 binding to the 3'UTR of STAT3 gene was detected by reported plasmid construction and luciferase assay. Furthermore, DSS-induced colitis mice model and T cell transfer model were used to confirm the function of miR-124 in vivo. The related gene expression was analyzed by ELISA and western blot experiments.

Results: The results indicated that miR-124 decrease promotes colon tumorigenesis after Citrobacter rodentium infection and AOM/DSS induced colon cancer murine model. In molecular mechanism, miR-124 targets STAT3 to inhibit TH17 cell polarization and keep TH17 polarization in colonic microenvironment.

Conclusions: Our study strengthened the important role of miR-124 in the regulation of adaptive immune responses and blocking the development of colitis-related cancer.

Keywords: STAT3; TH17 cell; colitis; colitis-related cancer; miR-124.