Abstract 5866: TESC mediates resistance to lenvatinib in hepatocellular carcinoma by regulating cell autophagy
Authors: Zhuang Hao , Zhang Tingting , Chen Jiaqi 
Published: March 2024

Abstract
Objective: To investigate the mechanism by which TESC (Tescalcin) induces lenvatinib resistance in hepatocellular carcinoma (HCC) through autophagy mediation.
Methods:1) Utilized established liver cancer organoids from over 70 patients for lenvatinib drug sensitivity screening and transcriptome sequencing to identify lenvatinib-resistant genes. 2) Constructed stable TESC overexpression and downregulation liver cancer cell lines. Employed CCK8 assays to plot IC50 drug sensitivity curves, elucidating changes in lenvatinib sensitivity in liver cancer cells after TESC overexpression or downregulation. 3) Used TESC-stable cells to establish subcutaneous tumor models and intrahepatic tumor models in nude mice. After tumor formation, administered lenvatinib orally to observe whether TESC affects liver cancer sensitivity to lenvatinib in vivo. 4) Conducted Western blot (WB) analysis to assess the expression of autophagy-related molecules (LC3B II/I, P62, and Beclin1 proteins) in TESC downregulated or overexpressed stable cell lines and their control cell lines. Utilized the LC3-GFP-mRFP fluorescence dual-labeling lentivirus system and laser confocal microscopy to examine autophagic flux. 5)Treated TESC downregulated cells with the autophagy inhibitor 3-MA. Conducted WB to assess the expression levels of autophagy-related proteins and plotted drug sensitivity curves using IC50 experiments to evaluate the impact of 3-MA on reversing liver cancer cell sensitivity to lenvatinib.
Results: Compared to the control group, HCC cells overexpressing TESC showed an increased IC50 value and reduced sensitivity to lenvatinib, while TESC downregulation resulted in a decreased IC50 value and decreased sensitivity to lenvatinib. Subcutaneous tumor experiments in nude mice indicated that, compared to the control group, tumors with reduced TESC expression were more sensitive to lenvatinib. Additionally, in HCC cells overexpressing TESC, protein expression levels of LC3B II/I and Beclin1 significantly decreased, while P62 expression increased. Conversely, TESC downregulation significantly increased protein expression levels of LC3B II/I and Beclin1, while P62 expression decreased. Furthermore, results from the LC3-GFP-mRFP autophagy dual-labeling lentivirus system showed a significant reduction in fluorescence spots in the TESC overexpression group compared to the control group, indicating weakened autophagic flux. Treatment of TESC downregulated liver cancer cells with 3-MA resulted in an increased IC50 value compared to the control group.
Conclusion: TESC expression levels are associated with the sensitivity of liver cancer cells to lenvatinib, possibly by inhibiting autophagy and affecting the sensitivity of liver cancer cells to lenvatinib.
Citation Format: Hao Zhuang, Tingting Zhang, Jiaqi Chen. TESC mediates resistance to lenvatinib in hepatocellular carcinoma by regulating cell autophagy [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 5866.