Abstract A12: Promotion of pancreatic cancer by perfluorooctanoic acid (PFOA)

Abstract Pancreatic cancer is the fourth leading cause of cancer deaths and one of the most lethal forms of cancer diagnosed in the United States. While the exact cause of pancreatic cancer is unknown, established risk factors for pancreatic cancer include smoking, alcohol consumption, and pancreatitis, all of which share the ability to generate oxidative stress—a condition known to promote cancer progression. Perfluorooctanoic acid (PFOA), a chemical widely used in consumer and industrial applications, has been shown to induce pancreatic acinar cell tumors in rodents through a yet to be determined mechanism. In humans, epidemiologic studies have linked PFOA exposure to adverse chronic health effects including several types of cancer. PFOA has been detected in essentially all of the American population, with mean serum levels close to 4 ng/ml and a predicted half-life of ~4 yrs. We have previously shown that exposure of mice to PFOA for 7 days triggered oxidative stress in the pancreas, which was associated with focal ductal hyperplasia and inflammation. The purpose of this study was to determine if PFOA exposure promotes the progression of pancreatic cancer in a well-characterized mouse model of pancreatic cancer, the LSL-KRasG12D;Pdx-1 Cre (KC) model. For our studies, KC mice received either tap water or tap water containing 5 ppm PFOA, starting at 2 months of age. Mice were sacrificed at 6 and 9 months of age, corresponding to 4 and 7 months of PFOA treatment, at which time serum and tissues were collected. Pancreata were processed for histologic examination (H&E stain), Alcian Blue (AB) staining, used as a marker to identify neoplastic lesion area, and RNA isolation for gene expression. Amylase, lipase, PFOA, and inflammatory cytokines were quantified in serum. Our results show that PFOA accumulates in the serum and pancreas of treated KC mice. In 6-month-old KC mice, exposure to PFOA increased the total AB+ lesion area from 4.87% ± 1.65% to 7.71% ± 3.01%. While the average lesion size was similar between control and PFOA-treated groups, the number of lesions per mm2 increased from 8.73 ± 3.19 to 16.73 ± 6.31, demonstrating that PFOA exposure leads to increased lesion development. qPCR analysis of pancreata verified increased expression of lesion markers CK19 and Sox9 in PFOA-treated mice. Analysis of mRNA expression in the pancreas revealed an increase in oxidative stress, evidenced by elevated Sod1 expression, and an increase in inflammatory markers (Tnfα and IL1α). Collectively, these results demonstrate that PFOA leads to expansion of the pancreatic lesion area in the LSL-KRasG12D;Pdx-1 Cre mouse model, which is accompanied by oxidative stress and an inflammatory response. These results, coupled with the widespread human exposure to PFOA and its biologic persistence, suggest that it may participate in promoting pancreatic cancer progression. Citation Format: Barbara A. Hocevar, Lisa M. Kamendulis. Promotion of pancreatic cancer by perfluorooctanoic acid (PFOA) [abstract]. In: Proceedings of the AACR Special Conference on Environmental Carcinogenesis: Potential Pathway to Cancer Prevention; 2019 Jun 22-24; Charlotte, NC. Philadelphia (PA): AACR; Can Prev Res 2020;13(7 Suppl): Abstract nr A12.