TanshinoneIIA ameliorates inflammatory microenvironment of colon cancer cells via repression of microRNA-155

► We built a cell mode between inflammatory macrophages and colon cancer cells. ► TSA indirectly inhibits proliferation of colon cancer cells. ► The mechanism relies on TSA decreased production of inflammatory cytokines. ► TSA decreased miR-155 via repression of PU.1. ► TSA restores SHIP1, which is a negative regulator of inflammation.