Abstract 4449: Hepatic steatosis induced by bioactive lipids

Abstract Introduction: HCC is the most common form of liver cancer and is the sixth most common cancer globally. Despite the clinical advancement of immune checkpoint inhibitors, median survival continues to be less than twenty months and most patients develop resistance making it one of the deadliest malignancies. The rate of liver cancer continues to rise, which is coupled to the high prevalence of steatosis and steatohepatitis that accounts for about 25% in the general population. Pathologically, 80% of liver cancer occurs in patients with an underlying liver disease that displays liver steatosis. Thus, it is paramount to better characterize the transition from steatosis to HCC. Methods: Utilizing a Pten deleted mouse model (PtenloxP/loxP; Alb-Cre+) that recapitulates HCC progression, protein and lipid fractions were isolated to explore differentially expressed proteins and their correlations with bioactive lipid metabolism. Global untargeted differential proteomics was done with fractionation using a qExactive. Lipid fractions were analyzed using a Sciex 6500 for targeted lipidomic analysis. In addition, genetic knockout hepatocyte cell lines of each AKT isoform were used to explore the involvement of the PI3K/AKT signal. Further, a phosphoproteomic enrichment was performed to discover downstream signaling targets. Results: The PTEN regulated PI3K/AKT signal is induced in 54% of all liver cancers and represents the dominant signaling pathway regulating liver cancer progression. Untargeted differential proteomic analysis of Pten deleted mice livers revealed significant dysregulation in oxidative stress and eicosanoid metabolism among the top enriched disease and biological functions when the phenotype progressed from steatosis to HCC. Analysis of publicly available liver cancer patient samples from the NCI Proteomic Data Commons further shows strong correlation between PTEN protein abundance and the expression of enzymes involved in eicosanoid metabolism. Our analysis using a bio-active lipid multi reaction monitoring panel of Pten deleted mouse livers further validates significant decreases in resolving eicosanoid levels along with increases in proinflammatory eicosanoid precursors as steatosis progress to HCC. These data suggest a potential hepatic AKT-dependency in regulating the shift towards proinflammatory eicosanoids. Primary isolated hepatocytes from mouse livers lacking either AKT1 or AKT2 were analyzed to elucidate AKT’s regulatory role in hepatic eicosanoid metabolism. Proteomic and lipidomic analysis of these hepatocytes supported a unique AKT isoform specific role in the regulation of eicosanoids via potential isoform specific signaling interactions with MAPK. Conclusion: Eicosanoid metabolism dysregulation plays a key role in the progression from steatosis to HCC and appears to be regulated in an AKT isoform specific manner via interactions with MAPK signaling. Citation Format: Mario Alba, Ielyzaveta Slarve, Brandon Ebright, Yiren Zhou, Whitaker Cohn, Yunyi Jia, Elizabeth Elton, Jared Khan, Aditi Datta, Lina He, Qi Tang, Pranav Pammidimukkala, Taojian Tu, Phillip Nguyen, Jonathan Katz, Julian Whitelegge, Stan Louie, Bangyan Stiles. Hepatic steatosis induced by bioactive lipids [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4449.