Abstract 2767: Aneuploidy-induced VHL haploinsufficiency in lung squamous cell carcinoma and clear cell renal cell carcinoma

Aneuploidy is present in 90% of solid tumors, making it a hallmark of cancer. Despite its prevalence, aneuploidy has been difficult to model in human cells due to the technical challenges of generating targeted events. One high-frequency aneuploidy alteration is chromosome 3p (chr3p) deletion, which is found in 80% of lung squamous cell carcinomas (LUSC) and 90% of clear cell renal cell carcinomas (ccRCC). Cells with chr3p deletion are missing one copy of the Von Hippel-Lindau (VHL) gene, a master regulator that targets Hypoxia Inducible Factor Subunit Alpha (HIF-α) for degradation. When HIF-α is not degraded, it promotes the transcription of genes involved in cell metabolism, cell survival, and proliferation. The role of VHL has already been extensively studied in ccRCC, but only using models with homozygous VHL loss, therefore the effect of heterozygous VHL loss is not known. I hypothesize that partial VHL loss is enough to stabilize HIF and activate transcriptional targets involved in tumor progression in LUSC. To study the effects of chr3p deletion, we developed a CRISPR-based approach to generate isogenic cell lines with and without the aneuploidy event in lung airway epithelial cells. Seven of eleven chr3p deleted clones had HIF-α protein stabilization in normoxic conditions. We also generated cells with smaller regions of chr3p deleted instead of whole arm loss. If the deletion region included VHL, we observed HIF-α accumulation. To test whether VHL haploinsufficiency was sufficient for this phenotype, we used CRISPRi to reduce VHL to 50% levels and found stabilization of HIF-α. In hypoxic conditions, VHL knockdown cells had increased HIF-α protein accumulation and gene expression of HIF-α targets GLUT1 and VEGF. These preliminary data suggest that VHL haploinsufficiency is enough to cause HIF-α stabilization. Additionally, we looked at VHL knockdown in renal epithelial cells and saw no HIF stabilization. This indicates that VHL haploinsufficiency and HIF stabilization may differ in lung vs. kidney cells. To our knowledge, our research is among the first to study VHL in lung cancer, and our results could have significant implications for drug development in LUSC. HIF-α inhibitors have recently been approved by the FDA, so determining the dose dependency of VHL on HIF-α activity will increase knowledge on treatment efficacy for patients with heterozygous deletion of VHL. Citation Format: Joanna Kopko, Joan J. Castellano-Perez, Gayatri Bulsara, Alison Taylor. Aneuploidy-induced VHL haploinsufficiency in lung squamous cell carcinoma and clear cell renal 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 2767.