Abstract B041: TIMP1-Mediated regulation of angiogenesis differs between KRAS-Dependent and KRAS-Independent cells in NSCLC

Abstract Non–small cell lung cancer (NSCLC) remains a major cause of cancer mortality, with EGFR and KRAS representing two of the most frequently mutated driver genes. KRAS-mutant tumors often exhibit oncogene addiction, relying on sustained KRAS signaling for survival and displaying varying degrees of KRAS dependency. However, certain mutations enable tumor cells to bypass KRAS signaling and transition into a KRAS-independent state, a shift commonly associated with epithelial–mesenchymal transition (EMT). In our recent publication, we demonstrated that TIMP-1 levels inversely correlate with KRAS expression across multiple NSCLC cell lines, and that shRNA-mediated TIMP-1 modulation alters KRAS dependency. We have investigated angiogenic alterations in KRAS-dependent and KRAS-independent cells following TIMP-1 overexpression or knockdown. KRAS-dependent cells (H2009, H441), which exhibit low endogenous TIMP-1, were engineered to overexpress TIMP-1, whereas KRAS-independent cells (H460, SKLU-1, A549), which express high TIMP-1, were subjected to TIMP-1 knockdown. TIMP-1 modulation demonstrated an inverse correlation with Thrombospondin-1 (TSP-1) expression across all lines. To further assess downstream signaling, we examined c-Myc, given prior evidence that c-Myc upregulation suppresses TSP-1. Consistent with our earlier findings that ERK activity is elevated in KRAS-dependent cells and further enhanced by TIMP-1 overexpression, c-Myc exhibited a similar pattern: its levels increased upon TIMP-1 overexpression in KRAS-dependent cells, while KRAS-independent cells showed low basal c-Myc expression with no significant changes following TIMP-1 knockdown. We have also performed RNA sequencing on all the mentioned cell lines and their TIMP1 OE/KD clones to identify KRAS-dependent and KRAS-independent pathways related to angiogenesis. In addition, angiogenic profiling of 55 analytes (R&D Systems) across the TIMP-1–modulated clones revealed consistent regulation of TSP-1, IL-8, and VEGF in both KRAS-dependent and KRAS-independent models, further supporting a TIMP-1–linked angiogenic axis. Together, our results highlight TIMP-1 as a key regulator of angiogenesis in NSCLC, in a KRAS-dependency–specific manner. Citation Format: Ilamathi M-Thirusenthilarasan, Pankaj Ahluwalia, Bilal Siddiqui, Ravindra Kohle, Amyn Rojiani, Mumtaz Rojiani. TIMP1-Mediated regulation of angiogenesis differs between KRAS-Dependent and KRAS-Independent cells in NSCLC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RAS Oncogenesis and Therapeutics; 2026 Mar 5-8; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(5_Suppl_1):Abstract nr B041.