Abstract B108: Integrated in vivo dissection of metastatic phenotypes and molecular programs in pancreatic ductal adenocarcinoma

Abstract

Abstract The ability of pancreatic ductal adenocarcinoma (PDAC) cells to form tissue destructive metastases remains a critical impediment to therapy. Metastasis is a complex multistep process that is poorly understood and the molecular events and cellular states that enable cancer cells to overcome each step of the metastatic cascade remain elusive. To investigate the regulators of PDAC metastasis, we accrued and characterized a panel of 31 cell lines generated from mouse models of PDAC. Initial experiments indicated that these cell lines have an ~40-fold difference in their ability to form lung metastases after transplantation into immunocompetent recipient mice. To more accurately quantify the relationship between metastatic seeding, growth, organ tropism, and immune evasion across all cell lines in parallel, we tagged each cell line with a barcode that provides both cell line-level and subclonal-level resolution. We pooled all 31 barcoded cell lines, transplanted them to seed metastases in different organs, and performed barcode sequencing on DNA from the metastasis-bearing tissues after short (seeding) and long (expansion) time periods. Neither seeding nor metastatic outgrowth correlated with growth in culture. Metastatic seeding did not directly correlate with overall metastatic burden, indicating that these processes depend on distinct biological processes. Transplantation into syngeneic immune-competent and immune-deficient recipient mice quantified the impact of immune responses towards each cell line. Bulk and single cell RNA-sequencing uncovered unexpected intra- and inter-cell line heterogeneity. Future experiments will integrate the data on metastatic phenotypes with molecular information to uncover drivers and inhibitors of each step of the metastatic cascade. Broad-scale molecular profiling coupled with quantitative in vivo analysis of metastatic phenotypes will uncover the relationships between metastatic phenotypes, create a resource for the community, and reveal novel pathways that govern PDAC metastasis, which could have implications for developing novel therapeutic strategies. Citation Format: Saswati Karmakar, Anastasia Lyulina, Xiaochen Xiong, Yuning J. Tang, Steven Lopez, Nicolas William Hughes, Laura Attardi, Dmitri A. Petrov, Monte M. Winslow. Integrated in vivo dissection of metastatic phenotypes and molecular programs in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B108.