Resistance to gemcitabine is mediated by the circ_0036627/miR-145/S100A16 axis in pancreatic cancer.

The development of gemcitabine (GEM) resistance severely limits the treatment efficacy in pancreatic cancer (PC) and increasing evidence highlights the vital roles of circular RNAs (circRNAs) in the tumorigenesis, progression and drug resistance of PC. However, the circRNAs underlying GEM resistance development of PC remains to be clarified. The current research aims to unveil the roles of circ_0036627 in dictating the aggressiveness and GEM sensitivity in PC. We reported the increased expression of circ_0036627 in PC tissues and PC cell lines. Elevated circ_0036627 expression level was correlated with advanced tumour grade and poor overall survival in PC patients. Functional assays and in vivo experiments demonstrated that circ_0036627 overexpression was required for the proliferation, migration invasion and GEM resistance in PC cells. circ_0036627 knockdown suppressed tumour development in vivo. The molecular analysis further showed that circ_0036627 increased S100A16 expression by sponging microRNA-145 (miR-145), a tumour-suppressive miRNA that could significantly attenuate PC cell proliferation, migration, invasion and GEM resistance. Furthermore, our findings suggested that S100A16 acted as an oncogenic factor to promote aggressiveness and GEM resistance in PC cells. In conclusion, the current findings provide new mechanistic insights into PC aggressiveness and GEM resistance, suggesting the critical role of circ_0036627/miR-145/S100A16 axis in PC progression and drug resistance development and offering novel therapeutic targets for PC therapy.