Abstract 6799: The impact of targeting TRAF2 and NCK-interacting protein kinase on anti-tumor effect and tumor immune environment in cMYC-high small cell lung cancer

Abstract Background: Small cell lung cancer (SCLC) is a highly lethal malignancy with rapidly acquired chemotherapy resistance. While the inflamed SCLC subtype is associated with a significantly improved response to immunotherapy, the non-inflamed SCLC subtypes, encompassing most SCLC patients, experience only modest survival gains with chemo-immunotherapy. Wnt signaling pathway activation is associated with resistance to chemotherapy and an immune checkpoint inhibitor in several tumors. TRAF2 and NCK-interacting protein kinase (TNIK), which interacts with downstream effectors, TCF4/β-catenin transcriptional complex, is an essential activator of Wnt target genes. TNIK is highly expressed in several cancers, but the efficacy of TNIK inhibition in SCLC has not previously been researched. We previously demonstrated that single agent TNIK inhibitors are effective in a subset of SCLC. Here, we hypothesize that targeting TNIK will show an anti-tumor effect based on specific biomarkers and also modify the tumor immune environment in SCLC. Methods: We evaluated susceptibility to a small molecule TNIK inhibitor, NCB-0846, in 29 human-derived SCLC cell lines using 96-hour proliferation assays. To investigate efficacy biomarkers, we correlated NCB-0846 IC50 values with proteomic expression (profiled using reverse phase protein array). cMYC and FOXK1 expression was reduced by siRNA. Chemokine concentrations were determined by ELISA. Results: SCLC cell lines with high cMYC levels, were more sensitive to the TNIK inhibitor, NCB-0846 (F.C.=-2.07, p=0.01), while SCLC cell lines with high expression of TTF-1 were more resistant (F.C.=2.48, p<0.01). Knockdown of cMYC conferred resistance to NCB-0846 in cMYC-high cells, while NCB-0846 treatment resulted in decreased cMYC expression in a concentration-dependent manner. Additionally, NCB-0846 treatment decreased the immunosuppressive chemokine CCL2 levels in the supernatant of human-derived SCLC cell lines and GEMM-derived cell lines. The expression of FOXK1, a transcription factor of CCL2, was also reduced in cell lines treated with NCB-0846. Conclusions: These findings show that TNIK inhibition is more effective in cMYC-high SCLC, acting through downregulating cMYC levels. TNIK inhibition also decreases the production of CCL2, an immunosuppressive chemokine implicated in resistance to anti-PD-L1 immunotherapy. Together, these findings highlight the promising potential of TNIK inhibitors in cMYC-high SCLC. Additionally, suppressing CCL2 by TNIK inhibition supports the rationale for combining the TNIK inhibitor and an anti-PD-L1 antibody in the non-inflamed SCLC subtypes. Citation Format: Azusa Tanimoto, Kavya Ramkumar, Allison Stewart, Bingnan Zhang, Robert Cardnell, Shen Li, Qi Wang, Jing Wang, Carl Gay, Lauren Averett Byers. The impact of targeting TRAF2 and NCK-interacting protein kinase on anti-tumor effect and tumor immune environment in cMYC-high small cell lung cancer [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 6799.