Ether-lipids accumulation promotes hepatocellular carcinoma progression linked to PPARα deficiency.

Abstract

Background: While the Warburg effect links glycolysis to de novo lipid synthesis in carcinogenesis, the roles of lipids in cancer prognosis remain elusive. Here, a multi-omics approach was conducted in a cohort of hepatocellular carcinoma (HCC) to elucidate the role of lipid metabolites as prognostic markers.

Methods: Ninety-eight HCC patients were recruited between 2011 and 2013. Their specimens were subjected to transcriptomic and lipidomic profiling. The resulting data were then analyzed using strategic bioinformatics approaches to identify associations with HCC prognosis. Subsequently, lipid-related pathways implicated in these analyses were verified using cellular and molecular approaches.

Results: Our findings indicate that lipidomic profiling is a potential prognostic marker for HCC. Specifically, higher levels of ether-lipids were significantly associated with poor survival and adverse clinical features, such as advanced TNM stage and metastasis. Analysis of transcriptomic patterns within patient groups defined by lipidomic profiles revealed that ether-lipid abundance inversely correlated with PPAR signaling but positively correlated with the expression of metastasis-associated gene clusters (e.g., genes involved in ECM remodeling, adhesion, and migration). Functional studies verified that ether-lipids enhance cell mobility. Consistent with the proposed mechanism, treatment with a PPARα agonist reduced ether-lipid accumulation and cell mobility. Therefore, we delineated an axis whereby PPARα downregulation leads to ether-lipid accumulation, subsequently promoting cell mobility. Mechanistically, we propose that deficient PPARα-mediated lipophagy results in cellular ether-lipid accumulation. These lipids, in turn, promote cell mobility via Transient Receptor Potential Vanilloid 2 (TRPV2)-mediated cytoskeletal rearrangement.

Conclusion: This study identifies lipidome patterns as a risk factor for patient prognosis. Mechanistically, deficient PPARα-mediated lipophagy leads to the accumulation of ether-lipids within cancer cells, which in turn promotes cell mobility via calcium-dependent, TRPV2 channel-mediated cytoskeletal rearrangement.