Concomitant overexpression of mir-182-5p and mir-182-3p raises the possibility of IL-17-producing Treg formation in breast cancer by targeting CD3d, ITK, FOXO1, and NFATs: A meta-analysis and experimental study.

T cells are polarized toward regulatory T cells (Tregs) in tumor microenvironment by the shuttling of microRNAs that target T cell-activating signaling pathways. We evaluated the expression of the miR-182 cluster (miR-96, 182, and 183) in peripheral blood mononuclear cells (PBMCs) of patients with breast cancer (BC), and T cell polarization by the expression of FOXO1, NFATs, ITK, TCR/CD3 complex, and IL-2/IL-2RA. Twenty-six microRNAs overexpressed in tumor tissues and sera of these patients were extracted by a meta-analysis. Then, the expression of the miR-182 cluster was investigated in PBMCs and sera of these patients and correlated with their targets in PBMCs. Finally, miR-182 was cloned into Jurkat cells to evaluate its effects on T cell polarization. FOXO1, CD3d, ITK, NFATc3, NFATc4, and IL-2RA were targeted by miR-182, due to which their expression decreased in PBMCs of patients. Although IL-6, IL-17, and TGF-β increased after miR-182 transduction, IL-2 dramatically decreased. We revealed CD4 FOXP3 T cell differentiation in the miR-182-transduced group. Although miR-182 has inhibitory effects on T cells by the inhibition of FOXO1, TCR/CD3 complex, NFATs, and IL-2/IL-2RA signaling pathways, it increases FOXP3, TGF-β, and IL-17 expression to possibly drive T cell deviation toward the transitional state of IL-17-producing Tregs and Treg formation in the end.