Abstract 1747: Targeting NRF2-responsive kinases for the treatment of esophageal squamous cell carcinoma

Abstract Esophageal squamous cell carcinoma (ESCC) ranks as the 8th most commonly diagnosed cancer and the 6th leading cause of cancer-related deaths worldwide. NRF2 has been identified as a bona fide cancer driver in human ESCC, with mutation rates ranging from 10% to 22%. Hyperactivation of NRF2 promotes tumor growth, metastasis, and resistance to conventional therapies in ESCC. Evidence suggests that NRF2 also regulates kinases influencing ESCC phenotypes, though the specific kinases involved are yet to be identified. NRF2 ChIP-seq analysis revealed enrichment of 42 kinases, including Akt2 and Pkm, and 31 phosphatases, such as Pten and Dusp16, in the Keap1-/- mouse esophagus compared to wild-type tissue. We confirmed NRF2 binding at the promoter regions of Akt2 and Pten. mRNA expression profiling revealed enrichment of the PI3K/AKT, RAS, ERK, and GSK3β signaling pathways in the Keap1-/- esophagus relative to Nrf2-/-;Keap1-/- esophagus. Immunohistochemical staining showed overexpression of pAKT, p-mTOR, pS6, and PKM2 in the esophagus of both Keap1-/- and Sox2CreER;LSL-Nrf2E79Q/+ mice. Using PhosphoExplorer and PamChip arrays, we identified several kinases, including PI3K, as NRF2-responsive kinases in NRF2W24C-KYSE70 cells compared to isogenic NRF2null-KYSE70 cells, as well as in Sox2CreER;LSL-Nrf2E79Q/+ mouse esophageal epithelium versus wild-type tissue. In NRF2null-KYSE70 cells, expression of pAKT, pS6, p-PTEN, PIK3CA, AREG, and pEGFR was significantly downregulated compared to NRF2W24C-KYSE70 cells. Similar results were seen in NRF2D77V-KYSE180 cells treated with NRF2 siRNA. Furthermore, NRF2null-KYSE70 cells showed increased sensitivity to EGFR inhibitor (Gefitinib), PIK3CA inhibitor (Alpelisib), and AKT inhibitor (Capivasertib), compared to NRF2W24C-KYSE70 cells. Notably, Alpelisib and an NRF2 inhibitor (Pyrimethamine) synergistically suppressed NRF2W24C-KYSE70 cell growth. Consistent with these findings, pNRF2 expression correlated with PI3K signaling proteins, including pAKT and p-mTOR, in human ESCC tissues. These studies highlight the potential of combining an NRF2 inibitor with a PI3K pathway inhibitor as a promising therapeutic strategy for ESCC. Citation Format: Boopathi Subramaniyan, Zhaohui Xiong, Yahui Li, Chorlada Paiboonrungruang, Francis Spitz, M. Ben Major, Xiaoxin Chen. Targeting NRF2-responsive kinases for the treatment of esophageal squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1747.