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Gemcitabine plus cisplatin (GC) combination chemotherapy is the primary treatment for advanced bladder cancer (BC) with unresectable or metastatic disease. However, most cases develop resistance to this therapy. We investigated whether drug resistance could be targeted through metabolic reprogramming therapies. Metabolomics analyses in our lab's gemcitabine‐ and cisplatin‐resistant cell lines revealed increased phosphoglycerate dehydrogenase (PHGDH) expression in gemcitabine‐resistant cells compared with parental cells. Isocitrate dehydrogenase 2 (IDH2) gain of function stabilized hypoxia‐inducible factor1α (HIF1α) expression, stimulating aerobic glycolysis. In gemcitabine‐resistant cells, elevated fumaric acid suppressed prolyl hydroxylase domain‐containing protein 2/Egl nine homolog 1 (PHD2) and stabilized HIF1α expression. PHGDH downregulation or inhibition in gemcitabine‐resistant BC cells inhibited their proliferation, migration, and invasion. Cisplatin‐resistant cells showed elevated fatty acid metabolism, upregulating fatty acid synthase (FASN) downstream of tyrosine kinase. Using the fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitor erdafitinib, we inhibited malonyl‐CoA production, which is crucial for fatty acid synthesis, and thereby suppressed upregulated HIF1α expression. Combination treatment with NCT503 and erdafitinib synergistically suppressed tumor cell proliferation and induced apoptosis in vitro and in vivo. Understanding these mechanisms could enable innovative BC therapeutic strategies to be developed. [ABSTRACT FROM AUTHOR]

Bladder cancer (BC) is a common genitourinary malignancy that exhibits silent morbidity and high mortality rates because of a lack of diagnostic markers and limited effective treatments. Here, we evaluated the role of the lncRNA brain cytoplasmic RNA 1 (BCYRN1) in BC. We performed loss-of-function assays to examine the effects of BCYRN1 downregulation in T24 and BOY BC cells. We found that BCYRN1 downregulation significantly inhibited the proliferation, migration, invasion, and three-dimensional spheroid formation ability and induced apoptosis in BC cells. Additionally, gene set enrichment analysis (GSEA) using RNA sequences from tumor fractions showed that BCYRN1 downregulation decreased the expression of mRNAs associated with the cell cycle. These findings were supported by observations of G2/M arrest in flow cytometry assays. Finally, we examined the expression of serum exosomal BCYRN1 as a biomarker. Clinically, BCYRN1 expression in serum exosomes from patients with BC (n = 31) was significantly higher than that in healthy donors (n = 19; mean difference: 4.1-fold higher, p < 0.01). Moreover, in patients who had undergone complete resection of BC, serum exosomal BCYRN1 levels were significantly decreased (n = 8). Thus, serum exosomal BCYRN1 may be a promising diagnostic marker and therapeutic target in patients with BC. [ABSTRACT FROM AUTHOR]

In microRNA (miRNA) biogenesis, the guide-strand of miRNA integrates into the RNA induced silencing complex (RISC), whereas the passenger-strand is inactivated through degradation. Analysis of our miRNA expression signature of bladder cancer (BC) by deep-sequencing revealed that microRNA (miR)-145-5p (guide-strand) and miR-145-3p (passenger-strand) were significantly downregulated in BC tissues. It is well known that miR-145-5p functions as a tumor suppressor in several types of cancer. However, the impact of miR-145-3p on cancer cells is still ambiguous. The aim of the present study was to investigate the functional significance of miR-145-3p and BC oncogenic pathways and targets regulated by miR-145-5p/miR-145-3p. Ectopic expression of either miR-145-5p or miR-145-3p in BC cells significantly suppressed cancer cell growth, migration and invasion and it also induced apoptosis. The gene encoding ubiquitin-like with PHD and ring finger domains 1 (UHRF1) was a direct target of these miRNAs. Silencing of UHRF1 induced apoptosis and inhibited cancer cell proliferation, migration, and invasion in BC cells. In addition, overexpressed UHRF1 was confirmed in BC clinical specimens, and the high UHRF1 expression group showed a significantly poorer cause specific survival rate in comparison with the low expression group. Taken together, our present data demonstrated that both strands of miR-145 (miR-145-5p: guide-strand and miR-145-3p: passenger-strand) play pivotal roles in BC cells by regulating UHRF1. The identification of the molecular target of a tumor suppressive miRNAs provides novel insights into the potential mechanisms of BC oncogenesis and suggests novel therapeutic strategies., Competing Interests: The authors indicated no potential conflicts of interest.