Curcumin inhibits colon cancer malignant progression and promotes T cell killing by regulating miR-206 expression.

ABSTRACT

Colon cancer is a great threat to human health. Curcumin, as a traditional Chinese medicine extract with anti-tumor and anti-inflammatory effects, can affect the development of diverse human diseases including cancer. The aim of this research was to probe the mechanism by which curcumin regulates colon cancer progression. Colon cancer cells were processed with graded concentrations of curcumin. The proliferation and apoptosis of the treated cells were determined by MTT, colony formation assay and flow cytometry. Expression of signaling pathway-related proteins and programmed death-ligand 1 (PD-L1) was measured by western blotting. The effect of curcumin on tumor cell growth was verified through T cell-mediated killing and ELISA assays. The relationship between target gene expression and the survival rate of colon cancer patients was analyzed by a survival curve. Curcumin treatment restrained proliferation and accelerated apoptosis of colon cancer cells. It elevated miR-206 expression, which in turn affected colon cancer cell function. miR-206 enhanced colon cancer cell apoptosis and inhibited PD-L1 expression; thus, curcumin enhanced the killing effect of T cells on tumor cells by suppressing PD-L1 through inhibiting the JAK/STAT3 pathway. Patients with high expression of miR-206 had better survival rates than those with low expression. Curcumin can regulate miR-206 expression and inhibit the malignant behavior of colon cancer cells and enhance T cell killing through the JAK/STAT3 pathway.