Adipocytes reprogram glucose metabolism in cancer cells promoting metastasis
In the tumor microenvironment, adipocytes function as an alternate fuel source for cancer cells. However, whether adipocytes influence macromolecular biosynthesis in cancer cells is unknown. Here, we systematically characterized the bi-directional interaction between primary human adipocytes and ovarian cancer (OvCa) cells using multi-platform metabolomics, imaging mass spectrometry, [13C]-glucose isotope tracing, and gene expression analysis. We report that omental tumor explants and OvCa cells co-cultured with adipocytes divert part of the glucose from glycolysis and TCA cycle towards glycerol-3-phosphate (G3P) synthesis. Normoxic HIF1 protein, stabilized by adipokines, regulate this altered flow of glucose-derived carbons in cancer cells, resulting in increased synthesis of glycerophospholipids (GPL) and triacylglycerols. Blocking adipocyte-induced HIF1 expression increases lipid peroxidation levels in cancer cells and sensitizes them to ferroptosis-mediated cell death. Subsequently, the knockdown of HIF1 or G3P acyltransferase 3 (a regulatory enzyme of GPL synthesis) reduced metastasis in xenograft models of OvCa. In summary, we show that in an adipose-rich tumor microenvironment, cancer cells generate G3P as a precursor for critical membrane and signaling components, thereby promoting metastasis. Targeting biosynthetic processes specific to adipose-rich tumor microenvironments might be an effective strategy against metastasis.