Abstract 5555: Potential pathways underlying sorafenib resistance in hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC), the most prevalent form of liver cancer, is heavily influenced by socioeconomic and health disparities. In the Rio Grande Valley (RGV), risk factors such as Hepatitis B and C, diabetes, and non-alcoholic fatty liver disease (NAFLD) contribute significantly to HCC prevalence. McAllen, TX, ranks as the most obese city in the United States, compounding the HCC burden in this underserved area. Limited access to screening and early detection often results in late-stage diagnoses and poor outcomes. A deeper understanding of the molecular mechanisms driving HCC, particularly drug resistance, is crucial for improving early detection and treatment strategies. Our lab investigates the role of Y-Box Binding Protein 1 (YBX1) in HCC progression and resistance to sorafenib, the first-line tyrosine kinase inhibitor (TKI) for advanced HCC. YBX1, part of the Cold Shock Domain (CSD) protein superfamily, is a 324-amino acid protein involved in mRNA translation regulation via interactions with microRNAs and non-coding RNAs. While sorafenib shows initial efficacy, resistance frequently develops, and its mechanisms remain poorly understood. Methods: HCC cell lines were cultured following ATCC guidelines. Lentiviral overexpression plasmids for YBX1, incorporating GFP and a puromycin selection marker, were obtained from Abmgood. YBX1 expression was validated using Western blot and RT-PCR. Functional assays, including invasion, migration, proliferation, colony formation, and Xcelligence impedance analysis, were conducted to assess phenotypic changes. A phosphoproteome array identified kinase pathways influenced by YBX1, while specific kinase activators and inhibitors clarified YBX1-regulated signaling pathways linked to sorafenib resistance. Results: Analysis of The Cancer Genome Atlas (TCGA) confirmed that YBX1 expression is significantly elevated in HCC tumors compared to normal tissues and correlates with disease progression, metastasis, and poor survival. In vitro studies demonstrated that YBX1 overexpression (OE) enhanced invasion, migration, proliferation, and colony formation, while knockdown (KD) reduced these behaviors. Xcelligence assays further revealed accelerated proliferation in YBX1-OE cells and diminished growth in KD cells. Phosphoproteome analysis identified several kinases modulated by YBX1, and pathway analysis is ongoing to determine their roles in sorafenib resistance. Conclusion and Future Directions: We established GFP-expressing SK-Hep1 cell lines with stable YBX1 overexpression and knockdown, confirming YBX1’s role in driving oncogenic phenotypes in HCC. Ongoing proteomic studies aim to identify YBX1-associated proteins and pathways, with a focus on kinase modulation. These insights will enhance our understanding of sorafenib resistance mechanisms and inform the development of targeted therapies to overcome resistance in HCC. Citation Format: Yamile Abuchard Anaya, Ana Ayala Pazzi, Dennis Kwabiah, Veerababu Nagati, Ricardo Pequeno Bracho, Manish K. Tripathi. Potential pathways underlying sorafenib resistance in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5555.