KHSRP promotes the malignant behavior and cisplatin resistance of bladder cancer cells through the CLASP2/MAPRE1 axis.

Bladder cancer (BC) is a highly prevalent form of cancer worldwide, and cisplatin (CDDP) resistance poses a major challenge to patients. Cytoplasmic linker-associated protein 2 (CLASP2) is a member of the microtubule plus-end tracking protein family and is involved in the regulation of microtubule dynamics. In this study, we evaluated the influence of CLASP2 on BC progression and cisplatin resistance. Levels of CLASP2, HNRNPA1, NONO, ZRANB2, FUS, KHSRP and QKI in BC tissues and cells were tested by RT-qPCR. Protein levels of CLASP2 and KHSRP were detected by Western blot. Cell viability and IC50 of cisplatin-treated BC cells were measured by CCK-8. Cell proliferation and apoptosis were determined using colony formation assay and flow cytometry, respectively. RNA immunoprecipitation (RIP) and Co-immunoprecipitation (Co-IP) experiments were adopted to verify target genes of CLASP2. Cellular localization of CLASP2 and MAPRE1 was detected utilizing immunofluorescence staining. The xenograft tumor model was established in BALB/c nude mice. We found that iCLASP2 levels were increased in CDDP-resistant BC tissues and cells. Suppression of CLASP2 impeded BC cell proliferation and alleviated their resistance to CDDP. KHSRP positively influenced the stability of CLASP2 mRNA. There was a protein interaction between CLASP2 and MAPRE1. Silencing KHSRP or MAPRE1 reversed the effect exerted of CLASP2 on BC cells. CLASP2 decreased the sensitivity of BC to CDDP in vivo. Our results imply that CLASP2 contributes to tumorigenesis and cisplatin resistance in BC via targeting MAPRE1, thereby promoting BC progression and providing a new therapeutic target for BC treatment.