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BackgroundRently, the incidence of bladder cancer has been on the rise. Accumulating researches have been conducted to clarify the molecular mechanisms and potential therapeutic targets of bladder cancer. The present study aims to explore the regulatory mechanism of the urothelial carcinoma-associated 1 (UCA1)-miR-582-5p-ATG7 axis in bladder cancer.MethodsQuantitative real-time polymerase chain reaction was used to detect mRNA level. Relative protein expression was detected by western blot. wound healing assay and transwell were used to determine migration and invasion of cells. in addtion, luciferase reporter assay and immunohistochemistry were performed.ResultsUCA1 expression was upregulated in bladder cancer tissues and cells, while the depletion of UCA1 by shRNA resulted in the suppression of cell proliferation, invasion, migration, and drug resistance. Further studies demonstrated that UCA1 could directly interact with miR-582-5p, and that there was an inverse correlation between miR-582-5p and UCA1. In addition, we found that ATG7 is a target of miR-582-5p and can be downregulated by either miR-582-5p overexpression or UCA1 knockdown. In particular, the autophagy is reduced when UCA1 shRNA is introduced. Moreover, the in vivo experiment further demonstrated the contribution of UCA1 in bladder cancer including tumor growth, invasion, and migration, and UCA1 knockdown can inhibit the aforementioned activities.ConclusionThese results provided evidence for a novel UCA1 interaction regulatory network in bladder cancer, that is, UCA1-miR-582-5p-ATG7-autophagy axis. Our study provides a new insight into the treatment of bladder cancer.

Rationale: Ureteral obstruction-induced hydronephrosis is associated with renal fibrosis and progressive chronic kidney disease (CKD). Exosome-mediated cell-cell communication has been suggested to be involved in various diseases, including renal fibrosis. However, little is known regarding how exosomes regulate renal fibrosis in obstructed kidneys. Methods: We first examined the secretion of exosomes in UUO (unilateral ureteral obstruction) mouse kidneys and TGF-β1-stimulated tubular epithelial cells (NRK-52E). Exosomes from NRK-52E cells were subsequently harvested and incubated with fibroblasts (NRK-49F) or injected into UUO mice via the tail vein. We next constructed Rab27a knockout mice to further confirm the role of exosome-mediated epithelial-fibroblast communication relevant to renal fibrosis in UUO mice. High-throughput miRNA sequencing was performed to detect the miRNA profiles of TGFβ1-Exos. The roles of candidate miRNAs, their target genes and relevant pathways were predicted and assessed in vitro and in vivo by setting specific miRNA mimic, miRNA inhibitor, siRNA or miRNA LNA groups. Results: Increased renal fibrosis was associated with prolonged UUO days, and the secretion of exosomes was markedly increased in UUO kidneys and TGF-β1-stimulated NRK-52E cells. Purified exosomes from TGF-β1-stimulated NRK-52E cells could activate fibroblasts and aggravate renal fibrosis in vitro and in vivo . In addition, the inhibition of exosome secretion by Rab27a knockout or GW4869 treatment abolished fibroblast activation and ameliorated renal fibrosis. Exosomal miR-21 was significantly increased in TGFβ1-Exos compared with Ctrl-Exos, and PTEN is a certain target of miR-21. The promotion or inhibition of epithelial exosomal miR-21 correspondingly accelerated or abolished fibroblast activation in vitro , and renal fibrosis after UUO was alleviated by miR-21-deficient exosomes in vivo through the PTEN/Akt pathway. Conclusion: Our findings reveal that exosomal miR-21 from tubular epithelial cells may accelerate the development of renal fibrosis by activating fibroblasts via the miR-21/PTEN/Akt pathway in obstructed kidneys.

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Ferroptosis, a novel form of regulated cell death characterized by disrupted iron metabolism and the accumulation of lipid peroxides, has exhibited enormous potential in the therapy of cancer particularly clear cell renal cell carcinoma (ccRCC). Luteolin (Lut), a natural flavonoid widely existing in various fruits and vegetables, has been proven to exert potent anticancer activity in vitro and in vivo. However, previous studies on the anticancer mechanism of Lut have been shown in apoptosis but not ferroptosis. In the present study, we identified that Lut substantially inhibited the survival of ccRCC in vitro and in vivo, and this phenomenon was accompanied by excessively increased intracellular Fe2+ and abnormal depletion of GSH. In addition, Lut induced the imbalance of mitochondrial membrane potential, classical morphological alterations of mitochondrial ferroptosis, generation of ROS, and occurrence of lipid peroxidation in an iron-dependent manner in ccRCC cells. However, these alterations induced by Lut could be reversed to some extent by the iron ion chelator deferiprone or the ferroptosis inhibitor ferrostatin-1, indicating that ccRCC cells treated with Lut underwent ferroptosis. Mechanistically, molecular docking further established that Lut probably promoted the heme degradation and accumulation of labile iron pool (LIP) by excessively upregulating the HO-1 expression, which led to the Fenton reaction, GSH depletion, and lipid peroxidation in ccRCC, whereas blocking this signaling pathway evidently rescued the Lut-induced cell death of ccRCC by inhibiting ferroptosis. Altogether, the current study shows that the natural compound monomer Lut exerted anticancer efficacy by excessively upregulating HO-1 expression and activating LIP to trigger ferroptosis in ccRCC and could be a promising and potent drug candidate for ccRCC treatment.