Abstract LB-241: Cancer-associated fibroblasts modulate growth- and metastasis-promoting pathways in human pancreatic cancer cells and augment orthotopic tumor growth in mice

Abstract

Abstract Background: The role of cancer-associated fibroblasts (CAFs) in the development, progression, and metastasis of pancreatic ductal adenocarcinoma (PDAC) is not completely understood. We sought to better characterize the role of CAFs by evaluating the effect of co-culturing CAFs and pancreatic cancer cells on growth and metastasis pathways. Methods: Resected human PDACs were grown orthotopically in mice. From these tumors, human pancreatic cancer cells and mouse CAFs were isolated and grown in culture. Three cell culture environments were created: 1) pure (>99%) human pancreatic cancer cells, 2) pure (97%) mouse CAFs, and 3) co-culture of both cell types. IHC and FACS were used to confirm cell type and species of origin. Phospho-receptor tyrosine kinase (pRTK) and cytokine arrays were performed on the three groups. Additionally, the effect of CAFs on PDAC growth was evaluated in nude mice by orthotopically injecting cancer cells (1 × 106 cells) with and without CAFs (1 × 106 cells). Results: CAFs stained positively for -smooth muscle actin (-SMA) but were negative for E-cadherin, while cancer cells stained positively for E-cadherin, but not -SMA. FACS for MHC-I confirmed mouse origin of the CAFs (negative) and human origin of the cancer cells (positive). Co-culture of mouse fibroblasts and human tumor cells led to significant upregulation of cell proliferation pathways (evidenced by increased human pRTKs and cytokines, including EGFR1, EGFR2, c-Met, Ron, IGF-1R, and thrombospondin-2), angiogenic pathways (evidenced by increased secretion of VEGF, IL-8, and angiogenin) and matrix degradation and remodeling pathways (increased secretion of MMPs 8 and 9, TIMPs 1 and 4, and uPA). Orthotopic mouse injection of human pancreatic cancer cells in combination with mouse CAFs (1:1 ratio) led to larger tumors at 3 weeks as compared to injection with cancer cells alone (1129 mm3 vs. 443 mm3, p < 0.005). Conclusions: Using co-culture of CAFs and pancreatic cancer cells we have recapitulated the modulation of pathways responsible for cell proliferation, angiogenesis, and matrix remodeling thought to occur in vivo during tumor progression. Further, we show that co-injection of CAFs and pancreatic cancer cells significantly augments orthotopic tumor growth in mice. These studies lay the groundwork for future studies to define the critical factors produced by stromal fibroblasts and the role of such factors in PDAC progression, allowing new insights into improving patient therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-241.