Role of long-chain acyl-CoA synthetases in MASH-driven hepatocellular carcinoma and ferroptosis.

Metabolic dysfunction-associated steatohepatitis-driven hepatocellular carcinoma (MASH-HCC) incidence is rapidly rising worldwide. Lipid metabolic reprogramming is a hallmark of solid tumors to satisfy cancer's high metabolic demand. However, it may confer sensitivity to ferroptosis, a cell death mode driven by iron-dependent lipid peroxidation. In this report, we describe the lipid metabolic landscape in MASH-HCC and characterize long-chain acyl-CoA synthetases (ACSLs), a family of enzymes involved in the synthesis of cellular lipids. Bulk RNA sequencing, single-cell RNA sequencing, spatial transcriptomics, and immunohistochemistry analyses of human MASH-HCC were integrated to identify differentially expressed lipid metabolism genes. Ferroptosis in vitro was assessed in human HCC cell lines. The characterization of ACSLs was also conducted at the single-cell level in a diet-induced experimental murine model of MASH-HCC. Our analysis revealed that in human MASH-HCC, ACSLs exhibit a heterogeneous expression, with ACSL4 notably enriched in tumor tissues, contrasting with ACSL5 upregulation in noncancerous MASH. We identified a unique lipid metabolic gene signature of MASH-HCC, which included genes associated with ferroptosis vulnerability. In vitro, high ACSL4 expression was associated with increased ferroptosis sensitivity in human HCC cell lines. Finally, single-cell RNA sequencing revealed elevated ACSL4 expression in immune cells in a murine MASH-HCC model, suggesting a role of ACSL4 in shaping the tumor immune microenvironment. Overall, this report offers new insights into the lipid metabolic landscape and ferroptosis sensitivity for novel MASH-HCC treatments.NEW & NOTEWORTHY Our study examined healthy human MASH and MASH-associated hepatocellular carcinoma (MASH-HCC) livers using bulk and scRNA sequencing, spatial transcriptomics, and immunohistochemistry. We found that ACSLs displayed differential and spatially heterogeneous expression. ACSL4 was abundant in tumor tissues, whereas ACSL5 was elevated in noncancerous MASH tissues. ACSL4 was mainly found in immune cells like natural killer cells and natural killer T cells in murine MASH-HCC, suggesting its role in tumor immune microenvironment modulation.