Patey Prize 2 O8 Characterisation of Pancreatic Stellate Cell (psc) Exosomes and Their Impact on Pancreatic Cancer Cell Phenotype

O8 CHARACTERISATION OF PANCREATIC STELLATE CELL (PSC) EXOSOMES AND THEIR IMPACT ON PANCREATIC CANCER CELL PHENOTYPE SM Robinson (1,2), DA Mann (1), J Mann (1), RM Charnley (2), SA White (1,2) (1) Institute of Cellular Medicine, Newcastle University (2) Freeman Hospital, Newcastle upon Tyne Introduction: Background Exosomes vesicles measuring up to 100nm in size and play key roles in cellto-cell communication. They are particularly rich sources of miRNA and are therefore a means by which one cell can impact on the gene expression and phenotype of neighbouring cells. Pancreatic cancer has a dense stroma of which PSCs are a key component. The aim of this study is to characterise PSC exosomes and their impact on pancreatic cancer cell phenotype. Method Exosomes were isolated from conditioned media of PSCs. Their RNA content was isolated and the miRNA cargo identified using the nanostring system. Pancreatic cancer cell lines MiaPACA2 and PANC1 were exposed to exosomes in 2D and 3D culture. Result The top 15 miRNA’s identified in exosomes were implicated in a variety of cancer associated KEGG pathways e.g. proteoglycans in cancer (p<0.0001), pancreatic cancer (p<0.0001), p53 signalling (p<0.0001), pathways in cancer (p<0.0001) involving over 620 genes. MiaPACA2 cells treated with exosomes demonstrate a 27% reduction in proliferation (p<0.05) whereas this is not seen in PANC1 cells. Exosome treatment reduced the sensitivity of PANC1 cells but not miaPACA2 cells to Gemcitabine. MiaPACA2 cells do not form spheroids in hanging drop culture however in the presence of exosomes do form 3D structures. PANC1 formed more compact spheroids in the presence of exosomes (p<0.001). This was associated with increased expression of cell adhesion genes e.g. CTGF (p<0.01), uPAR (p<0.01). Conclusion PSC exosomes contain miRNA’s implicated in a variety of cancer related cell signalling processes and impact on the phenotype of pancreatic cancer cells. Take-home message: PSC exosomes appear to have an impact on the phenotype of pancreatic cancer cells.