Abstract PR010: Aging-induced reprogramming of the cell of origin defines lung cancer evolution

Abstract Aging is one of the most important risk factors for cancer development. However, our understanding of how aging impacts cancer evolution remains at an early stage. We investigated the evolution of lung adenocarcinoma (LUAD) in aged vs. young KrasLSL-G12D/+; Trp53flox/flox (KP) mice. Surprisingly, we found that LUAD initiation and progression were significantly impaired with aging. Using functional in vivo and in vitro assays, we demonstrated that the loss of tumor-initiating potential could be attributed to a loss of stemness in the alveolar type 2 (AT2) cells, which are the predominant cell of origin for LUAD. We next explored the biology of the tumors that formed in aged KP mice using single-cell transcriptomics. We discovered a distinct compositional landscape of cancer cell subsets in aged lung tumors, revealing a delay in the molecular progression of the cancers and an aging-specific gene expression signature. Interestingly, key components of this gene signature could be traced back to specific epigenetic alterations in the AT2 cells. Furthermore, the aged mouse LUAD signature was highly predictive of patient age in human LUAD, indicating conservation of the age-associated changes across species. We hypothesized that the aging-associated changes in gene expression during LUAD tumorigenesis may underpin delayed tumor progression in the aged KP mice. To test this, we performed an in vivo genetic screen in the autochthonous KP model and identified genetic dependencies that were specific to LUAD in aged or young mice. Our results indicate that aging-associated epigenetic changes in the cell of origin are imprinted on evolving tumors, which determines tumor initiation potential, alters trajectory of tumor evolution, and leads to age-dependent vulnerabilities. These findings suggest that the biology of tumors is fundamentally altered by aging, raising new possibilities for cancer treatment and prevention in patients of different ages. Citation Format: Xueqian Zhuang, Simon Joost, Qing Wang, Melissa Blum, Selena Ding, Zhuxuan Li, Yingqian Zhan, Richard Koche, Emily Wong, Tuomas Tammela. Aging-induced reprogramming of the cell of origin defines lung cancer evolution [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr PR010.