Abstract 4741: Targeting sorafenib-resistant HCCs by protein X-armed T cell immunotherapy

Abstract

Abstract Hepatocellular carcinoma (HCC) is the most common type of liver cancer globally, ranking fourth according to the World Health Organization's GLOBOCAN database. Sorafenib and lenvatinib are single-drug therapies used for advanced HCC, but only around 30% of patients benefit from them, and drug resistance typically develops within a few months. Our previous study has demonstrated the specific IL-6-IGF-1R-YAP signaling in regulating the stemness expressions, tumor metastasis, and drug-resistance of the sorafenib resistant HCC (2015 Clinical Cancer Res, 2019 J Exp Clinical Cancer Research, 2021 Cancers, 2023 Cancers). In advance our previous study, this study aims to develop a novel immune therapeutic strategy for sorafenib-resistant HCC treatment. We found, when compared to peri-tumor tissues, the immunohistochemical staining showed a high co-expression of both protein X and PD-L1 in liver tumor tissues (6.25%, n=32 versus 28.125%, n = 64, respectively). To further confirm this observation, we used in vitro cell line models with sorafenib-naïve HCCs (HepG2215_N, Hep3B_N, Huh7_N, and PLC5_N) and sorafenib-resistant HCCs (HepG2215_R, Hep3B_R, Huh7_R, and PLC5_R) in this study. As PD-L1 on tumor cells can dampen T cell cytotoxicity, we generated CD3/protein X bispecific antibodies, which can bind to both CD3 and protein X, and coupled them to T cells (Arm-T cells) and normal T cells (N-T cells). We tested their cytotoxic effects on sorafenib-resistant HCCs using the sorafenib-resistant HepG2215_R cells, co-cultured with Arm-T cells and N-T cells for 24 hours. Our results showed that Arm-T cells exhibited a significantly stronger cytotoxic effect on sorafenib-resistant HepG2215_R cells, with several notable findings: (1) The binding time of Arm-T cells to HepG2215_R cells was significantly longer than that of N-T cells (248.9 ± 146.6 minutes, n=23 versus 28.3 ± 13.49 minutes, n=24); (2) The cytotoxicity of Arm-T cells was significantly higher than that of N-T cells (29.7 ± 2.3% versus 13.6 ± 3.3%); and (3) The secreted levels of INFγ and TNFα by Arm-T cells were significantly higher than those of N-T cells (138.1 ± 7.2 ng/ml and 34.6 ± 0.7 ng/ml versus 31.4 ± 2.5 ng/ml and 3.6 ± 1.1 ng/ml, respectively). These findings were also consistent when using Hep3B-R cells (data not shown). To summarize, our study shows that Arm-T cells possess strong cytotoxic abilities against sorafenib-resistant HCC. These findings have implications for developing effective immuno-therapeutic strategies for patients with sorafenib-resistant HCCs. Citation Format: Mai-Huong Thi Ngo, Michael Chen, Pei-Chi Lan, Kuo-Hsiang Chuang, Yen-Hua Huang. Targeting sorafenib-resistant HCCs by protein X-armed T cell immunotherapy [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 4741.