Loss of activating transcription factor 3 prevents KRAS-mediated pancreatic cancer

The unfolded protein response (UPR) is activated in pancreatic pathologies and suggested as a target for therapeutic intervention. In this study, we examined activating transcription factor 3 (ATF3), a mediator of the UPR that promotes acinar-to-ductal metaplasia (ADM) in response to pancreatic injury. Since ADM is an initial step in the progression to pancreatic ductal adenocarcinoma (PDAC), we hypothesized that ATF3 is required for initiation and progression of PDAC. We generated mice carrying a germline mutation of Atf3 (Atf3(-/-)) combined with acinar-specific induction of oncogenic KRAS (Ptf1a(creERT/+)Kras(G12D/+)). Atf3(-/-) mice with (termed APK) and without KRAS(G12D) were exposed to cerulein-induced pancreatitis. In response to recurrent pancreatitis, Atf3(-/-) mice showed decreased ADM and enhanced regeneration based on morphological and biochemical analysis. Similarly, an absence of ATF3 reduced spontaneous pancreatic intraepithelial neoplasia (PanIN) formation and PDAC in Ptf1a(creERT/+)Kras(G12D/+) mice. In response to injury, KRAS(G12D) bypassed the requirement for ATF3 with a dramatic loss in acinar tissue and PanIN formation observed regardless of ATF3 status. Compared to Ptf1a(creERT/+)Kras(G12D/+) mice, APK mice exhibited a significant decrease in pancreatic and total body weight, did not progress through to PDAC, and showed altered pancreatic fibrosis and immune cell infiltration. These findings suggest a complex, multifaceted role for ATF3 in pancreatic cancer pathology.

Automated summary

The study suggests a critical role of ATF3 in pancreatic cancer development through promoting ADM and PanIN formation. Loss of ATF3 can reduce response to pancreatic injury and decrease the incidence of PDAC.