Interrogating the Spatial and Functional Relevance of Microbes in Pancreatic Cancer and Metastasis

Abstract/ Summary Pancreatic ductal adenocarcinoma (PDAC) represents one of the most aggressive malignancies, with more than 50% of patients with pancreatic cancer presenting with metastatic disease, mainly in the liver, at the time of diagnosis. We have previously described the presence of microbes in

pancreatic cancer which could determine outcomes. Furthermore, we revealed that microbial modulation can affect tumor microbial composition, immune cells landscape and tumors growth. We have now preliminary data showing microbial distribution across tumors and cellular compartments. Moreover, we have been able to perform spatial microbial functional assessment

at regional and single cell level. We have identified similar microbes in primary tumors and matched liver metastasis, suggesting microbial seeding from primary tumors to liver. More evidence for this is our findings revealing that NETosis, a process of host defense against microbes, is upregulated in liver during the metastatic process. The overall goal of this proposal

is to deeply characterize the location, distribution and spatial functionality of microbes within the tumor microenvironment of primary tumors as well as their influence in tumors growth, pre- metastatic niche and liver metastasis formation. To this end, we will use multiple methodologies including state-of-the-art microbial-host imaging, regional and single cell microbial-host

sequencing to determine the location of bacteria within the cellular compartments, patterns of distribution, functionality and species characterization together with screening culturomics (Aim 1). We will then use multiple mouse models to fully characterize the role of human PDAC microbes in primary tumor growth, metastatic niche and liver metastasis formation by adding human-

pancreatic cancer derived microbes allowing in vivo tracking of microbial-containing cancer cells as well as local and global microbial ablation, in vitro organoid microbial co-cultures and assessment/modulation of NETosis to determine their role in mediating microbial effects (Aim 2). The success of this proposal has high potential for the development of novel microbial modulation

strategies that target the tumor microenvironment which could ultimately lead to improved outcomes in patients with pancreatic cancer.