We surveyed the range of small-molecule compounds that inhibit Mint3-mediated HIF-1 activation and identified naphthofluorescein, which blocked the interaction between Mint3 and FIH-1 in vitro and suppressed Mint3-dependent HIF-1 activity and glycolysis in cancer cells and macrophages without causing cytotoxicity in vitro. Here, HIF1A is linked to cancer.