RNA binding protein Pumilio2 promotes chemoresistance of pancreatic cancer via focal adhesion pathway and interacting with transcription factor EGR1.

Pancreatic cancer (PCa) has insidious onset, high malignancy and poor prognosis. Gemcitabine (GEM) is one of the first-line chemotherapy drugs for PCa. However, GEM resistance has always been a bottleneck problem leading to recurrence and death of PCa patients. RNA-binding proteins (RBPs) are important proteins that regulate transportation, splicing, stability and translation of RNA. Abnormal expression of RBPs often lead to a series of abnormal accumulation or degradation of downstream RNA resulting in various diseases. In our study, we utilized RIP seq, RIP-qPCR, in vitro and in vivo experiments and found that pumilio2 (PUM2) was high expression in PCa, and promoted GEM resistance of PCa by regulating mRNA stability of integrin Alpha 3 (ITGA3) and other genes in focal adhesion pathway, and there was positive feedback regulation between PUM2 and transcription factor early growth response gene 1 (EGR1), that is PUM2 binding to 3'UTR region of EGR1 mRNA, and EGR1 binding to promoter region of PUM2 gene. The discovery of EGR1/PUM2/ITGA3 axis provided a solid experimental basis for the selection of chemotherapy regiments for PCa patients and exploration of combined regimens to reverse GEM resistance in the future.