Abstract 3087: Targeting AURKA and TRIP13 exploits mitotic vulnerability and enhances antitumor immunity in Rb-deficient immunocompetent lung cancer models

Abstract Rb loss is a common event in multiple cancers and creates vulnerabilities that can be therapeutically exploited. We previously reported that HPV-positive, Rb-deficient cancers depend on two mitotic checkpoint regulators, Aurora kinase A (AURKA) and TRIP13, for proper mitotic exit. Dual inhibition of these proteins induces mitotic catastrophe and cell death. To determine whether this dependency extends beyond HPV-driven tumors and affects the tumor immune microenvironment, we evaluated the combination of AURKA and TRIP13 inhibition in Rb-deficient lung cancer models. To test the combination, we used the TRIP13 inhibitor DCZ0415 and the AURKA inhibitor alisertib. We first assessed the ability of DCZ0415 to inhibit TRIP13. Consistent with previous reports, DCZ0415 binds to TRIP13 as confirmed by CETSA and affinity chromatography assays. Treatment of cancer cells with 10µM DCZ0415 reduced MAD2 association with CDC20 in pull-down assays, indicating that DCZ0415 selectively interferes with TRIP13-mediated MAD2 conversion. TRIP13 ATPase activity was largely unaffected, suggesting a kinase-independent inhibitory mechanism. The IC50 values for DCZ0415 in murine non-small cell lung cancer (NSCLC) cell lines were 20μM for 344SQ and 16μM for 344P, as determined by CellTiter-Glo assays. In apoptosis assays (Annexin V), DCZ0415 alone did not induce measurable cell death, while alisertib (200 nM) resulted in ∼25% apoptosis after 72 hours. In contrast, the combination treatment produced significantly greater apoptosis. In 344SQ cells, the combination induced ∼40% cell death, compared with 4.6% for DCZ0415 and 25% for alisertib alone. Similar findings were observed in 344P cells, with combination treatment inducing ∼55% apoptosis. We next evaluated the combination in a PD1-resistant, Rb-deficient immunocompetent mouse model. The combination produced a marked reduction in tumor growth compared with either agent, with significant differences apparent by day 14. Preliminary immunoprofiling of tumor-infiltrating immune cells (TILs) revealed several combination-specific effects. Dendritic cell abundance increased, suggesting enhanced antigen presentation within the tumor. The combination also reduced myeloid-derived suppressor cell (MDSC) levels in the tumor, indicating a shift toward a less suppressive tumor immune microenvironment. Additionally, TIL analysis showed increased overall T-cell infiltration, with both CD4+ and CD8+ T-cell populations elevated relative to single agents. T-cell polyfunctionality was also enhanced, as indicated by higher frequencies of GZMB+ and IFNγ+ effector T cells. Together, these findings identify combined AURKA and TRIP13 inhibition as a promising therapeutic approach for Rb-deficient cancers and provide the first in vivo evidence of its efficacy and immune-modulating potential in NSCLC. Citation Format: Soma Ghosh, Jennifer L. Anderson, Andrew G. Sikora, Faye M. Johnson. Targeting AURKA and TRIP13 exploits mitotic vulnerability and enhances antitumor immunity in Rb-deficient immunocompetent lung cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 3087.