Abstract 2025: Phosphoproteomic profiling following MAP3K1 kinase inhibition identifies NPM1 as a novel substrate

Abstract

Abstract In response to diverse cellular cues, MAP3K1, a mitogen-activated protein kinase, participates in various cancer signaling networks including the NFκB, JNK, ERK, and p38 pathways. Functioning as a signaling kinase in these oncogenic pathways, MAP3K1 contributes to tumor growth and metastasis, thus making it an attractive therapeutic target for cancer. Structure-guided design using MAP3K1 AlphaFold and Schrödinger GLIDE led to the development of 51-106, a selective MAP3K1 small molecule inhibitor. Profiling using the KiNativTM platform in a cellular matrix revealed 51-106 as a selective ATP-competitive MAP3K1 inhibitor. 51-106 blocked TNFα-induced MAP3K1-IKKβ-mediated NFκB activity. Phosphoproteomics analysis following MAP3K1 inhibition by 51-106 showed a dose dependent decrease in NPM1 T199 phosphorylation indicating NPM1 as a novel substrate of MAP3K1. NPM1 plays a critical role in DNA damage repair; consistently we observed a dose dependent S-phase arrest upon MAP3K1 inhibition by 51-106, suggesting a dysfunctional DNA damage response. Higher MAP3K1 transcript level in pancreatic cancer patients is associated with poorer (50% vs. 15%) 5-year survival. Treatment of pancreatic cancer cell lines with the MAP3K1 inhibitor 51-106 inhibited cell growth and migration. In combination studies, 51-106 synergistically inhibited growth with gemcitabine in LSL-KrasG12D/+, LSL-Trp53R172H/+, Pdx1-Cre (KPC) cell lines in vitro and in KPC syngeneic orthotopic implantation mouse model of pancreatic cancer in vivo. Our study is the first to identify NPM1 as a potential substrate of MAP3K1, and these results warrant the investigation of MAP3K1 inhibition as a therapeutic option in cancer. Citation Format: Lidia Boghean, Sarbjit Singh, Kiran Mangalaparthi, Surendra K. Shukla, Smitha Kizhake, Amritha Kizhake, Donn Wishka, Jayapal Reddy Mallareddy, Joel Morris, Paul Grothaus, Pankaj K. Singh, Akhilesh Pandey, Amarnath Natarajan. Phosphoproteomic profiling following MAP3K1 kinase inhibition identifies NPM1 as a novel substrate [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 2025.