The Anti-tumor Activity Of DC/CTL Induced By Pancreatic Cancer Derived Exosome And Its Ultrafiltered Lysate

Objective:To observe the impact of pancreatic cancer derived exosome and ultrafiltered exosome lysate on the anti-tumor activity of DC/CTL cells and demonstrate the mechanism.Methods:exosome derived from SW1990cells (human pancreatic cancer line) were collected by ultracentrifugation and low-osmotic splitting followed by ultrafiltration were performed to remove exosomal microRNAs and purify the ultrafiltered exosome lysate. ImDC(immature dendritic cells) were induced from peripheral blood and co-cultured with CTL(cytotoxic lymphocyte), which were impulsed by exosome and ultrafiltered exosome lysate respectively. The concentration of TNF-a and perform in culture medium supernatant were examined by ELISA. CCK-8kit was used to evaluate the cytotoxic activity of DC/CTL to SW1990cells.ResultsThe concentration of TNF-a and perform of E-DC/CTL group were129.54pg/ml and2.68ng/ml respectively, lower than that of DC/CTL (189.72pg/ml and3.71ng/ml) and EL-DC/CTL (207.13pg/ml and3.92ng/ml).The killing rates of E-DC/CTL was34.17%, lower than that of DC/CTL(49.19%) and EL-DC/CTL (68.62%) significantly. The Killing rate of EL-DC/CTL was significantly higher than that of DC/CTL (P<0.05).Conclusion:SW1990cells derived exosome inhibit the anti-tumor activity of DC/CTL by down-regulating TNF-α and perforin, and exosomal miRNA may play important roles in the immune escape of pancreatic cancer.We set up a new model based on ultrafiltered exosome lysate derived from pancreatic cancer to enhance the anti-tumor activity of DC/CTL.