Abstract 2772: Mechanisms linking STK11 loss with metastatic potential in KRAS-mutated lung adenocarcinoma

Abstract Metastasis is one of the major determinants of worsened patient prognosis and occurs in roughly 50% of lung adenocarcinoma (LUAD) patients at the time of diagnosis. Late-stage diagnosis of LUAD often results in the accumulation of a wide range of mutations in tumor cells, with altered KRAS being the most frequently encountered oncogenic driver. Co-mutation of the tumor suppressor STK11 is also common and occurs in 10-15% of KRAS-driven LUAD. Retrospective patient studies have demonstrated that concurrent oncogenic KRAS and STK11 loss-of-function mutations are associated with metastatic disease, poorer patient survival, and inferior therapy response. The purpose of this study was to identify molecular mechanisms by which STK11 loss results in a greater metastatic potential in KRAS-driven LUAD in hopes of exploiting that knowledge to improve patient outcomes. For our studies, we utilized the KRAS-mutated, STK11-intact human LUAD cell line NCI-H2009. Both parental and ∆STK11 (generated by CRISPR/Cas9) H2009 cells were seeded in Transwell® inserts coated with fibronectin. As expected, H2009 ∆STK11 cells displayed a 1.6-fold increase in trans-well migration compared to the parental line (SEM 14393 ± 877.3 cells, n=6; p<0.0001). To assess the invasive properties of parental and ∆STK11 cells in a three-dimensional environment, spheroids generated by hanging drop culture were embedded in Matrigel and imaged by light microscopy at zero and 24-hours post-embedding. Analysis demonstrates a 2.4-fold increase in invasion in ∆STK11 cells compared to parental cells (SEM 0.03 ± 0.01 mm2, n=19-21; p<0.0001). Three-dimensional LUAD spheroids have been reported to more closely recapitulate in-vivo tumor transcriptomes compared to two-dimensional monolayer cultures. qRT-PCR analyses of our spheroids demonstrate that loss of STK11 promotes a significant increase in the expression of lung cancer stem cell markers CXCR4, NANOG, CD44, and OCT4 (n=3-6; p<0.002). These markers are known to support stem cell maintenance, chemoresistance, as well as metastatic potential, suggesting a mechanistic link between STK11 and their transcriptional regulation. To assess the impact of STK11 loss on early and late-stage metastasis in-vivo, we will use an embryonic zebrafish xenograft model. Zebrafish represent a tractable metastasis model due to the number of conserved human homologs - most notable being the CXCR4/CXCL12 axis which models cross-communication between zebrafish endothelium and cognate human tumor ligands. Current and future studies focus on investigating the role of STK11 in regulating stem cell markers; thereby identifying potentially novel therapeutic targets for STK11 and KRAS co-mutated LUAD patients. Citation Format: Cole M. Royer, Lauren K. Bialek, Hailey M. Sarausky, Shannon M. Prior, Gopika Nandagopal, Paula B. Deming, David J. Seward, Melissa N. Scheiber. Mechanisms linking STK11 loss with metastatic potential in KRAS-mutated lung adenocarcinoma [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 2772.