Abstract 5014: HPK1 gene knockout reporter cell line: an efficient drug screening system

Abstract Immunotherapy is the stimulation of the immune system, improving on the ability of immune system to treat cancer. It is expected to be the most effective therapy for patients with tumor metastasis. Checkpoint inhibitor (CPI) therapy is a form of cancer immunotherapy which can block inhibitory checkpoints, restoring immune system function. Tumor cells could recruit immunomodulatory cells and induce inhibitory signals, resulting in losing immunomodulatory. Therefore, there is an urgent need to develop new therapeutic agents that work in concert with CPI. HPK1, also known as MAP4K1, can act as a negative regulator of activation signals generated by T cell receptor (TCR). The development and screening of HPK1 inhibitors have great potential in the cancer immunotherapy. Herein, we constructed a HPK1 knockout reporter cell line Jurkat-NFAT-Luc2-HPK1-Knockout-Cell-Line by CRISPR/Cas9 which can be used in high-throughput HPK1 inhibitors screening. Wild type cells were incubated with HPK1 inhibitors and luciferase signals were compared in HPK1-knockout cells. Our HPK1 knockout reporter cell line has high sensitivity and specificity. The reporter system can achieve high-throughput compound library screening. After selected the compound with selective inhibitory activity, further validation and optimization would be performed. Moreover, we constructed a Jurkat-HPK1-HiBiT reporter cell line by CRISPR/Cas9. It can be used in the screening of HPK1 degradants. We believe that HPK1 gene editing cell lines play an important role in the high-throughput screening of drugs. It could facilitate the development of drugs in tumor immunotherapy. Citation Format: Yunpeng Zhai, Lidan Li, Jianyu Hao, Yuqing Hu, Jinying Ning, Feng Hao. HPK1 gene knockout reporter cell line: an efficient drug screening system. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5014.