Cancer-Associated Endocrine Cells Participate in Pancreatic Carcinogenesis

Abstract

Background & AimsThe pancreas is composed of endocrine and exocrine parts, and its interlacing structure indicates potential interaction between endocrine and exocrine cells. Although the tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) has been well characterized, the role of pancreatic endocrine cells during carcinogenesis is relatively understudied. MethodsWe depicted the changes of endocrine cells in PDAC by single-cell transcriptome sequencing, spatial transcriptome sequencing and multiplex immunohistochemistry. After that, the interaction between pancreatic carcinogenesis and endocrine changes was explored in orthotopic transplantation mice, KC mice and KPC mice. Finally, we proved the mechanism of the interaction between endocrine and exocrine parts of the pancreas through islet isolation, co-culture in vitro and co-injection in vivo. ResultsWe found that pancreatic endocrine cells displayed significantly different transcriptomic characteristics and increased interaction with exocrine part in PDAC. Specifically, among all the changes, pancreatic polypeptide positive (PPY+) cells showed a sharp increment accompanied with the progression of the cancer lesion, which might be derived from the transdifferentiation of α and β cells. Interestingly, it was proved that PDAC cells were able to induce the transdifferentiation of pancreatic α cells and β cells into GCG+PPY+ and INS+PPY+ double-positive cells, which further promoted carcinogenesis and development of PDAC in a paracrine-dependent manner and formed a reciprocal interaction. ConclusionsOur study systematically maps the alteration of pancreatic endocrine cells in PDAC and elucidates the potential endocrine-exocrine interaction mechanisms during PDAC carcinogenesis. Meanwhile, we first time define and characterize cancer-associated endocrine cells (CAEs), thereby further broadening the composition of PDAC microenvironment.