Tuft Cells Inhibit Pancreatic Tumorigenesis in Mice by Producing Prostaglandin D2.

BACKGROUND & AIMS Development of pancreatic ductal adenocarcinoma (PDA) involves acinar to ductal metaplasia and genesis of tuft cells. It has been a challenge to study these rare cells due to lack of animal models. We investigated the role of tuft cells in pancreatic tumorigenesis. METHODS We performed studies with LSL-KrasG12D/+; Ptf1aCre/+ mice (KC, develop pancreatic tumors), KC mice crossed with mice with pancreatic disruption of Pou2f3 (KPouC mice, do not develop Tuft cells), or mice with pancreatic disruption of the hematopoietic prostaglandin D synthase gene (Hpgds, KHC mice), and wild-type mice. Mice were allowed to age or were given caerulein to induce pancreatitis; pancreata were collected and analyzed by histology, immunohistochemistry, RNA sequencing, ultrastructural microscopy, and metabolic profiling. We performed laser-capture dissection and RNA sequencing analysis of pancreatic tissues from 26 patients with pancreatic intraepithelial neoplasias (PanINs), 19 patients with intraductal papillary mucinous neoplasms (IPMN), and 197 patients with PDA. RESULTS Pancreata from KC mice had increased formation of tuft cells and higher levels of prostaglandin D2 than wild-type mice. Pancreas-specific deletion of POU2F3 in KC mice (KPouC mice) resulted in a loss of tuft cells and accelerated tumorigenesis. KPouC mice had increased fibrosis and activation of immune cells following administration of caerulein. Pancreata from KPouC and KHC mice had significantly lower levels of PGD2, compared with KC mice, and significantly increased numbers of PanINs and PDAs. KPouC and KHC mice had increased pancreatic injury, following administration of caerulein, significantly less normal tissue, more extracellular matrix deposition, and higher PanIN grade than KC mice. Human PanIN and IPMN had gene expression signatures associated with tuft cells and increased expression of Hpgds mRNA compared with PDA. CONCLUSIONS In mice with KRAS-induced pancreatic tumorigenesis, loss of tuft cells accelerates tumorigenesis and increases the severity of caerulein-induced pancreatic injury, via decreased production of PGD2. These data are consistent with the hypothesis that tuft cells are a metaplasia-induced tumor attenuating cell type.