Tumor-derived Interleukin 35 Mediates the Dissemination of Gemcitabine Resistance in Pancreatic Adenocarcinoma

Rapid development of drug resistance after chemotherapy is a major cause of treatment failure in individuals with pancreatic ductal adenocarcinoma (PDAC). In this study, we illustrate that tumor-derived interleukin 35 (IL-35) mediates the accelerated resistance of PDAC to gemcitabine (GEM). We observe that GEM resistance can spread from GEM-resistant PDAC cells to GEM-sensitive cells, and that IL-35 is responsible for the propagation of chemoresistance, which is supported by sequencing and experimental data. Additionally, we discover that GEM-resistant cells have significantly higher levels of IL-35 expression. Mechanistically, aberrantly expressed IL-35 triggers transcriptional activation of SOD2 expression via GP130-STAT1 signaling, scavenging reactive oxygen species (ROS) and leading to GEM resistance. Furthermore, GEM treatment stimulates IL-35 expression through activation of the NF-κB pathway, resulting in acquired chemoresistance. In the mouse model, a neutralizing antibody against IL-35 enhances the tumor suppressive effect of GEM. Collectively, our data suggests that IL-35 is critical in mediating GEM resistance in pancreatic cancer, and therefore could be a valuable therapeutic target in overcoming PDAC chemoresistance.