Abstract B17: Tumor-associated stellate cells promote an invasive phenotype of pancreatic cancer cells

Abstract

Abstract At the time of diagnosis, almost 80% of pancreatic cancer patients present with either new-onset type 2 diabetes or impaired glucose tolerance. Pancreatic cancer is associated with a highly abundant stroma, which is believed to influence the pathogenesis of the disease. In the local tumor microenvironment, both elevated glucose levels and the presence of tumor-associated stellate cells are hypothesized to promote the tumor progression and invasion by tumor cells. In this study, the influence by the microenvironment on pancreatic cancer cell invasion was investigated in vitro. Epithelial-to-mesenchymal transition (EMT) of human pancreatic cancer cells co-cultured in normal (5mM) or high (25 mM) glucose conditions with tumor-associated pancreatic stellate cells (TPSCs) was monitored by Western immunoblotting. In addition, a three-dimensional organotypic model was established to study and visualize the pancreatic cancer cell invasion. After co-culture, the expression of several EMT-markers was altered. The levels of E-cadherin were reduced by more than 95% (P<0.001) while vimentin was increased by 45% (P<0.05). In addition, high glucose conditions reduced the levels of ZO-1 and β-catenin compared to normal glucose. TGF-β stimulation, a known inducer of EMT, resulted in a similar modulation of EMT markers. The organotypic model showed differences in the extent of invasion between the cell lines investigated, of which PANC-1 human pancreatic cells were shown to be the most invasive and also formed a highly proliferative epithelium. In high glucose conditions, the invasion of PANC-1 cells appeared to increase both in number and distance covered by the cells. Immunofluorescent staining of EMT-markers in organotypic sections displayed a lack of E-cadherin and extensive expression of vimentin in the tumor epithelium. In conclusion, this study show TPSCs to induce changes in pancreatic cancer cells associated with enhanced invasiveness. In addition, a three-dimensional model visualized the invasive potential of the pancreatic cancer cells, which was further enhanced by high glucose conditions. This study contributes to further elucidate the interplay between, and influence of, the cell types present in the local tumor microenvironment, which promotes the tumor cell invasion as an important step in the pancreatic tumor progression. Citation Format: Emelie Karnevi, Ann H. Rosendahl, Moin A. Saleem, Roland Andersson. Tumor-associated stellate cells promote an invasive phenotype of pancreatic cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B17.