Hypoxia-driven phase separation of the PABP1/eIF4B complex forms stress granules and activates ChaC2 translation to promote polyunsaturated lipids-supported peritoneal metastasis in gastric cancer.

Highly metastatic cancer cells depend on polyunsaturated fatty acids (PUFAs) to enhance membrane fluidity, yet this adaptive advantage concurrently renders them more susceptible to ferroptosis. However, the adaptation and survival strategies of metastatic gastric cancer (GC) cells under severe stress conditions remain unclear. To identify driver genes underlying peritoneal metastasis (PM) in GC, we performed integrated multi-omics analyses of GC tissues, followed by validation using a large cohort of clinical samples (n = 124) and corresponding prognostic data. Both in vitro and in vivo functional studies confirmed that ChaC2 is a critical driver of PM from GC. Mechanistic investigations revealed that ChaC2 attenuates ferroptosis sensitivity caused by elevated PUFAs levels in metastatic GC cells. Under hypoxic conditions, HIF-1α transcriptionally upregulates eIF4B and promotes cytoplasmic translocation of PABP1, leading to liquid-liquid phase separation (LLPS) of the PABP1/eIF4B complex. This phase-separated structure recruits G3BP1 to nucleate stress granules (SGs), within which ChaC2 mRNA is selectively sequestered, thereby enhancing its stability and translational efficiency. Collectively, our findings demonstrate that hypoxia-induced PABP1/eIF4B LLPS specifically upregulates ChaC2 expression, enabling metastatic cancer cells to evade ferroptosis triggered by their own metastatic demands and ultimately facilitating tumor dissemination. This study uncovers a critical adaptive regulatory mechanism employed by metastatic GC cells to cope with stress challenges during PM, thereby offering novel therapeutic targets and strategic insights for intervention.