Abstract 771: A TGF-β superfamily member, myostatin contributes to MASH and HCC via muscle atrophy by disrupting TGF-β signaling, and is a potential marker with PKM2 for human HCC

Abstract Background: In patients with cirrhosis and hepatocellular carcinoma (HCC), sarcopenia or skeletal muscle loss, as well as metabolic alterations are frequent and progressive comorbidities. Myostatin, a TGF-β superfamily member is expressed primarily in skeletal muscle, inhibits muscle growth, and causes sarcopenia in cirrhosis. Previously, we had observed liver-specific knockout of the SMAD3 adaptor, βII-spectrin -Sptbn1 (βS-LSKO) or siRNA targeting βII-spectrin blocks sarcopenia, fatty liver disease-MASH and HCC (Sci TM 2021), suggesting that βII-spectrin may be a viable strategy to identify mechanisms, as well as new biomarkers of MASH and HCC. Methods: 1. SPTBN1Flox (control) and liver-specific βII-spectrin knockout (SPTBN1LSKO) mice were fed Western diet (WD) and treated with Diethylnitrosamine (DEN) for obesity-associated HCC. Muscle mass, body weight and multiple enzymes involved in glycolysis as well as sarcopenia were measured in mutant mice. 2. In tumors, a rate-limiting enzyme in glycolysis, pyruvate kinase isozyme M2 (PKM2) that mediates inflammation and aerobic glycolysis in Warburg effect. Therefore, we further examined TGF-β pathway-enriched biomarkers such as Myostatin and PKM2 for markers of HCC and whether these could stratify risk in patients with cirrhosis for HCC, in a four-institution cohort, (n=157) compared to cirrhosis patients (n=380). Results: 1. Like human fatty liver disease, obese mutant mice show marked sarcopenia with increased PKM2 and Myostatin levels with decreased p-RPS6/total-RPS6 ratio (indicating mTOR signaling inhibition) in striated muscle tissue. In contrast, levels are restored to normal in the liver specific knockout of SPTBN1. 2. Using the 108 markers as well as PKM2 and myostatin (MSTN), we found 31 markers with false discovery rate (FDR) p values < 0.10 from univariable Kruskal-Wallis tests for the associations of markers with HCC vs. cirrhosis. Conclusions: Our results reveal that SMAD3 adaptor, βII-spectrin liver-specific knockout decreases Myostatin and PKM2 expression, providing new insight into molecular mechanisms in MASH and HCC. These studies reflect that these are biologically functional circuits that could provide new serum markers, such as Myostatin and PKM2 for risk stratification of HCC. Citation Format: Kazufumi Ohshiro, Krishanu Bhowmick, Xiyan Xiang, Shivani Kapoor, Richard Amdur, Srinivasan Dasarathy, Adrian R. Krainer, Lopa Mishra. A TGF-β superfamily member, myostatin contributes to MASH and HCC via muscle atrophy by disrupting TGF-β signaling, and is a potential marker with PKM2 for human HCC [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 771.