Autophagic adaptation to oxidative stress alters peritoneal residential macrophage survival and ovarian cancer metastasis

Tumor-associated macrophages (TAMs) affect cancer progression and therapy. Ovarian carcinoma often metastasizes to the peritoneal cavity. Here, we found 2 peritoneal macrophage subsets in mice bearing ID8 ovarian cancer based on T cell immunoglobulin and mucin domain containing 4 (Tim-4) expression. Tim-4(+) TAMs were embryonically originated and locally sustained while Tim-4(–) TAMs were replenished from circulating monocytes. Tim-4(+) TAMs, but not Tim-4(–) TAMs, promoted tumor growth in vivo. Relative to Tim-4(–) TAMs, Tim-4(+) TAMs manifested high oxidative phosphorylation and adapted mitophagy to alleviate oxidative stress. High levels of arginase-1 in Tim-4(+) TAMs contributed to potent mitophagy activities via weakened mTORC1 activation due to low arginine resultant from arginase-1–mediated metabolism. Furthermore, genetic deficiency of autophagy element FAK family-interacting protein of 200 kDa resulted in Tim-4(+) TAM loss via ROS-mediated apoptosis and elevated T cell immunity and ID8 tumor inhibition in vivo. Moreover, human ovarian cancer–associated macrophages positive for complement receptor of the immunoglobulin superfamily (CRIg) were transcriptionally, metabolically, and functionally similar to murine Tim-4(+) TAMs. Thus, targeting CRIg(+) (Tim-4(+)) TAMs may potentially treat patients with ovarian cancer with peritoneal metastasis.