Abstract 2469: PROTAC mediated NR4A1 degradation as a novel strategy for cancer immunotherapy

Abstract An effective cancer therapy requires both killing cancer cells and targeting tumor-promoting pathways or cell populations within the tumor microenvironment (TME). We purposely search for molecules that are critical for multiple cell types in the TME and identified nuclear receptor subfamily 4 group A member 1 (NR4A1) as one such molecule. NR4A1 has been shown to promote the aggressiveness of cancer cells and maintain the immune suppressive TME. Using genetic and pharmacological approaches, we establish NR4A1 as a valid therapeutic target for cancer therapy. Importantly, we have developed the first-of-its kind proteolysis-targeting chimera (PROTAC, named NR-V04) against NR4A1. NR-V04 effectively degrades NR4A1 within hours of treatment in vitro and sustains for at least 4 days in vivo, exhibiting long-lasting NR4A1-degradation in tumors and an excellent safety profile. NR-V04 leads to robust tumor inhibition and sometimes eradication of established melanoma tumors. At the mechanistic level, we have identified an unexpected novel mechanism via significant induction of tumor-infiltrating (TI) B cells as well as an inhibition of monocytic myeloid derived suppressor cells (m-MDSC), two clinically relevant immune cell populations in human melanomas. Overall, NR-V04-mediated NR4A1 degradation holds promise for enhancing anti-cancer immune responses and offers a new avenue for treating various types of cancer such as melanoma. Citation Format: Lei Wang, Yufeng Xiao, Yuewan Luo, Rohan Master, Jiao Mo, Myung-Chul Kim, Yi Liu, Chandra Maharjan, Urvi Patel, Xiangming Li, Donald Shaffer, Guertin Kevin, Haoyang Zhuang, Emily Moser, Keiran Smalley, Daohong Zhou, Guangrong Zheng, Weizhou Zhang. PROTAC mediated NR4A1 degradation as a novel strategy for cancer 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 2469.