Expressed Sequence Tags-1-Targeted MiRNA-326 in Gastric Cancer Induces Local Immune Inflammatory Microenvironment by Inducing T Helper Cell 17 Cell Differentiation

Abstract

This study intends to assess miRNA-326’s effect on the immune-inflammatory microenvironment and its mechanism in gastric cancer (GC). GC adjacent tissues and tumor tissues were collected to analyze inflammatory factors by immunohistochemistry and ELISA, Est-1 and miRNA-326 level by Western blot or PCR, Th17 cells by flow cytometry. CD4+ T cells were transfected with Est-1 inhibitor, Est-1 mimics, or miR-326 mimics followed by measurement of Th17 differentiation-related genes via gene chips and inflammatory factor release. Inflammatory factors in serum of GC patients were significantly increased and miR-326 was upregulated with decreased Est-1 and unbalanced Th17/Treg cell ratio. miR-326 targeted Est-1 to inhibit its expression. After transfection with Est-1 inhibitor, Th17 differentiation-related genes were upregulated. After transfection with miR-326 mimics, Est-1 level was reduced and inflammation was enhanced with maturation of Th17 cells. In conclusion, miRNA-326 induces Th17 cell differentiation by targeting Est-1, thereby promoting the release of inflammatory factors and inducing immune inflammatory microenvironment.