1. MTA-cooperative PRMT5 inhibitors enhance T cell-mediated antitumor activity in MTAP-loss tumors.
- Author
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Chen S, Hou J, Jaffery R, Guerrero A, Fu R, Shi L, Zheng N, Bohat R, Egan NA, Yu C, Sharif S, Lu Y, He W, Wang S, Gjuka D, Stone EM, Shah PA, Rodon Ahnert J, Chen T, Liu X, Bedford MT, Xu H, and Peng W
- Subjects
- Animals, Mice, Humans, T-Lymphocytes immunology, T-Lymphocytes drug effects, Cell Line, Tumor, Female, Neoplasms drug therapy, Neoplasms immunology, Isoquinolines, Pyrimidines, Protein-Arginine N-Methyltransferases antagonists & inhibitors, Protein-Arginine N-Methyltransferases metabolism, Purine-Nucleoside Phosphorylase antagonists & inhibitors, Purine-Nucleoside Phosphorylase metabolism
- Abstract
Background: Hyperactivated protein arginine methyltransferases (PRMTs) are implicated in human cancers. Inhibiting tumor intrinsic PRMT5 was reported to potentiate antitumor immune responses, highlighting the possibility of combining PRMT5 inhibitors (PRMT5i) with cancer immunotherapy. However, global suppression of PRMT5 activity impairs the effector functions of immune cells. Here, we sought to identify strategies to specifically inhibit PRMT5 activity in tumor tissues and develop effective PRMT5i-based immuno-oncology (IO) combinations for cancer treatment, particularly for methylthioadenosine phosphorylase (MTAP)-loss cancer., Methods: Isogeneic tumor lines with and without MTAP loss were generated by CRISPR/Cas9 knockout. The effects of two PRMT5 inhibitors (GSK3326595 and MRTX1719) were evaluated in these isogenic tumor lines and T cells in vitro and in vivo . Transcriptomic and proteomic changes in tumors and T cells were characterized in response to PRMT5i treatment. Furthermore, the efficacy of MRTX1719 in combination with immune checkpoint blockade was assessed in two syngeneic murine models with MTAP-loss tumor., Results: GSK3326595 significantly suppresses PRMT5 activity in tumors and T cells regardless of the MTAP status. However, MRTX1719, a methylthioadenosine-cooperative PRMT5 inhibitor, exhibits tumor-specific PRMT5 inhibition in MTAP-loss tumors with limited immunosuppressive effects. Mechanistically, transcriptomic and proteomic profiling analysis reveals that MRTX1719 successfully reduces the activation of the PI3K pathway, a well-documented immune-resistant pathway. It highlights the potential of MRTX1719 to overcome immune resistance in MTAP-loss tumors. In addition, MRTX1719 sensitizes MTAP-loss tumor cells to the killing of tumor-reactive T cells. Combining MRTX1719 and anti-PD-1 leads to superior antitumor activity in mice bearing MTAP-loss tumors., Conclusion: Collectively, our results provide a strong rationale and mechanistic insights for the clinical development of MRTX1719-based IO combinations in MTAP-loss tumors., Competing Interests: Competing interests: JRA reports non-financial support and reasonable reimbursement for travel from European Society for Medical Oncology and Loxo Oncology; receiving consulting and travel fees from Ellipses Pharma, Molecular Partners, IONCTURA, Sardona, Mekanistic, Amgen, Merus, MonteRosa, Aadi and Bridgebio (including serving on the scientific advisory board); consulting fees from Vall d’Hebron Institute of Oncology/Ministero De Empleo Y Seguridad Social, Chinese University of Hong Kong, Boxer Capital, LLC, Tang Advisors, LLC and Guidepoint, receiving research funding from Blueprint Medicines, Merck Sharp and serving as investigator in clinical trials with Cancer Core Europe, Symphogen, BioAlta, Pfizer, Kelun-Biotech, GlaxoSmithKline, Taiho, Roche Pharmaceuticals, Hummingbird, Yingli, Bicycle Therapeutics, Merus, Aadi Bioscience, ForeBio, Loxo Oncology, Hutchison MediPharma, Ideaya, Amgen, Tango Therapeutics, Mirati Therapeutics, Linnaeus Therapeutics, MonteRosa, Kinnate, Yingli, Debio, BioTheryX, Storm Therapeutics, Beigene, MapKure, Relay, Novartis, FusionPharma, C4 Therapeutics, Scorpion Therapeutics, Incyte, Fog Pharmaceuticals, Tyra, Nuvectis Pharma. MTB is a co-founder of EpiCypher. No potential conflicts of interest were disclosed by other authors., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2024
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