The DNA methylation-regulated miR-193a-3p dictates the multi-chemoresistance of bladder cancer via repression of SRSF2/PLAU/HIC2 expression.

Chemoresistance hinders the curative cancer chemotherapy. To define the role of the DNA methylation-regulated microRNA (miR) genes in the chemoresistance of bladder cancer, we performed both DNA methylomic and miRomic analyses of a multi-chemosensitive (5637) versus a multi-chemoresistant (H-bc) cell line and found that miR-193a-3p is hypermethylated/silenced in 5637 and hypomethylated/expressed in H-bc cells. A forced reversal of its level turned around the chemoresistance in the cultured cells and the tumor xenografts in nude mice. Three of its targets: SRSF2, PLAU and HIC2, work in concert to relay the miR-193a-3p's impact on the bladder cancer chemoresistance by modulating the activities of the following five signaling pathways: DNA damage, Notch, NF-κB, Myc/Max, and Oxidative Stress. In addition to the mechanistic insights in how the newly identified miR-193a-3p/SRSF2,PLAU,HIC2/five signaling pathway axis regulates the chemoresistance of bladder cancer cells, our study provides a new set of diagnostic targets for the guided personalized chemotherapy of bladder cancer.