Cheating death: How a porphyrin transporter fuels survival in hypoxia

Heme is an important cofactor in biological processes such as oxidative phosphorylation, and its biosynthesis is altered in stress conditions including hypoxia. In this study, we uncovered a pivotal role for ABCB6, a porphyrin-transporting member of the ATP binding cassette family, in affecting porphyrin synthesis and survival under hypoxic conditions. We demonstrate that ABCB6 is a direct target of hypoxia-inducible factor 1, which is regulated through a conserved hypoxia response element in normal and tumor cells. Overexpression of ABCB6 significantly increased porphyrin synthesis and enhanced hypoxic survival, whereas ABCB6 deletion or suppression of porphyrin synthesis impaired survival under low oxygen conditions. Moreover, high ABCB6 expression correlated with poor prognosis, highlighting its clinical relevance. These findings establish ABCB6 as a key survival factor in hypoxia, regulated by porphyrin synthesis. Targeting ABCB6 could present a novel therapeutic strategy for cancers thriving in hypoxic microenvironments. Under hypoxia, hypoxia-inducible factor 1 drives significant upregulation of the porphyrin transporter ABCB6, triggering profound alterations in porphyrin levels and markedly enhancing hypoxic survival—an insight with critical clinical implications.