Targeting complex IV to alter the tumor microenvironment and boost macrophage antitumor immunity.

Clark et al. showcase that interferons (IFNs) trigger a functional reprogramming of tumor-associated macrophages (TAMs) by downregulating NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4 (NDUFA4), a key subunit of mitochondrial complex Ⅳ. This drives a transition from protumor TAMs to antitumor IFN-associated TAMs (IFN-TAMs) through activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway. This mechanism can be leveraged to boost antitumor immunity and improve responses to immune checkpoint blockade.