Stromal cues regulate the pancreatic cancer epigenome and metabolome

• Published in: Proceedings of the National Academy of Sciences - PNAS 2017-01, Vol.114 (5), p.1129-1134
• Main Authors: Sherman, Mara H., Yu, Ruth T., Tseng, Tiffany W., Sousa, Cristovao M., Liu, Sihao, Truitt, Morgan L., He, Nanhai, Ding, Ning, Liddle, Christopher, Atkins, Annette R., Leblanc, Mathias, Collisson, Eric A., Asara, John M., Kimmelman, Alec C., Downes, Michael, Evans, Ronald M.
• Format: Article
• Language: English
• Subjects: Acetylation; Biological Sciences; Carcinoma, Pancreatic Ductal - genetics; Carcinoma, Pancreatic Ductal - metabolism; Carcinoma, Pancreatic Ductal - pathology; Carcinoma, Pancreatic Ductal - physiopathology; Cells; Cytokines - metabolism; Energy Metabolism; Enhancer Elements, Genetic; Fibroblasts - physiology; Gene Expression Regulation, Neoplastic - genetics; Genomes; Histone Code; Humans; Intercellular Signaling Peptides and Proteins - metabolism; Metabolome; Mutation; Neoplasm Proteins - antagonists & inhibitors; Neoplasm Proteins - physiology; Pancreatic cancer; Pancreatic Neoplasms - genetics; Pancreatic Neoplasms - metabolism; Pancreatic Neoplasms - pathology; Pancreatic Neoplasms - physiopathology; Pancreatic Stellate Cells - physiology; Promoter Regions, Genetic; Protein Serine-Threonine Kinases - antagonists & inhibitors; Protein Serine-Threonine Kinases - physiology; Proteins; Stromal Cells - physiology; Transcription Factors; Tumor Cells, Cultured; Tumor Microenvironment - physiology; Tumors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1620164114

A fibroinflammatory stromal reaction cooperates with oncogenic signaling to influence pancreatic ductal adenocarcinoma (PDAC) initiation, progression, and therapeutic outcome, yet the mechanistic underpinning of this crosstalk remains poorly understood. Here we show that stromal cues elicit an adaptive response in the cancer cell including the rapid mobilization of a transcriptional network implicated in accelerated growth, along with anabolic changes of an altered metabolome. The close overlap of stroma-induced changes in vitro with those previously shown to be regulated by oncogenic Kras in vivo suggests that oncogenic Kras signaling—a hallmark and key driver of PDAC—is contingent on stromal inputs. Mechanistically, stroma-activated cancer cells show widespread increases in histone acetylation at transcriptionally enhanced genes, implicating the PDAC epigenome as a presumptive point of convergence between these pathways and a potential therapeutic target. Notably, inhibition of the bromodomain and extraterminal (BET) family of epigenetic readers, and of Bromodomain-containing protein 2 (BRD2) in particular, blocks stroma-inducible transcriptional regulation in vitro and tumor progression in vivo. Our work suggests the existence of a molecular “AND-gate” such that tumor activation is the consequence of mutant Kras and stromal cues, providing insight into the role of the tumor microenvironment in the origin and treatment of Ras-driven tumors.