Simulated microgravity induces HIF-1-dependent pseudohypoxic and glycolytic state in triple- negative breast cancer

With the expansion of commercial spaceflight and space exploration, the microgravity environment provides unparalleled opportunities to fight against challenging diseases. Here, we investigate the impact of simulated microgravity (sMG) on the cellular morphology and metabolic state of triple-negative breast cancer (TNBC). TNBC cells (SUM159 and MDA-MB-231) were exposed to sMG (~0.001 g) using a random positioning machine (RPM) for 1 and 3 days. Transcriptome profiling revealed that sMG induces a “pseudohypoxic” state, characterized by altered expression of genes typically associated with hypoxia, even under normoxic conditions. sMG upregulates HIF-1α protein levels and its target gene expression , and downregulates c-MYC and its target gene expression. In addition, sMG mediates metabolic reprogramming of TNBC cells by upregulating gene expression in glycolysis and downregulating gene expression in glutaminolysis and TCA cycle in a HIF-1-dependent manner. Metabolomic analysis further confirmed activation of glycolytic pathway under sMG. Our findings demonstrate that sMG induces a HIF-1-dependent pseudohypoxic and glycolytic state in TNBC cells and implicate a gravity-responsive HIF-1/c-MYC axis in metabolic control.