Abstract
Bladder cancer (BC) is a lethal cancer that threatens the health of millions of people. Chemotherapy drug resistance, for example, cisplatin (DDP) resistance, is a huge limitation for BC therapy. PTEN pseudogene-1 (PTENP1) has been identified as a significant biomarker of multiple cancers. Therefore, it is essential to illuminate the molecular mechanism of PTENP1 in BC cell DDP resistance and progression. Serum exosomes were isolated using an ExoQuick precipitation kit. Serum exosomes were round-shaped vesicles of 100 ± 60 nm in size. The expression of PTENP1 was down-regulated in serum exosomes isolated from cisplatin non-responsive patients compared with responsive patients. ROC curves certified the diagnostic value of PTENP1. Apparently, PTENP1 transfection inhibited DDP-resistant BC cell proliferation, migration, cisplatin resistance and facilitated apoptosis. Next, we discovered that PTENP1 was a sponge of miR-103a, while PDCD4 was a target of miR-103a. More importantly, PTENP1 regulated DDP-resistant cell viability, migration, apoptosis and cisplatin resistance by interacting with the miR-103a/PDCD4 axis. In addition, PTENP1 hindered tumor growth of cisplatin-resistant mice. Exosome-derived PTENP1 suppressed the DDP resistance of BC by inhibiting cell proliferation, migration and promoting apoptosis through regulating the miR-103a/PDCD4 axis, representing a targeted therapy for DDP-resistant BC patients.