Halogenated Boroxine K2 (B3O3F4 Oh) Modulates Metabolic Phenotype and Autophagy in Human Bladder Carcinoma 5637 Cell Line

Abstract Halogenated boroxine K2(B3O3F4OH), (HB) has effectively inhibited growth of several carcinoma cell lines. Because of the growing interest in autophagy induction as therapeutic approach in bladder carcinoma (BC), we aimed to assess the effects of HB on metabolic phenotype and autophagy levels in 5637 human bladder carcinoma cells (BC). Cytotoxicity was evaluated using alamar blue assay, and degree of autophagy was determined microscopically. Mitochondrial respiration and glycolysis were measured simultaneously. The relative expression of autophagy related genes BECN1, P62, BCL-2, and DRAM1 were determined by real time PCR. HB inhibited cell growth in concentration dependent manner. Starvation significantly increased level of autophagy in positive control compared to the basal level of autophagy in negative control. In HB treated cultures, the degree of autophagy was higher compared to the basal level and metabolic phenotype altered: both glycolysis and oxidative phosphorylation (OXPHOS) were decreased by HB at 0.2 and 0.4 mg/ml. Genes expression was deregulated towards autophagy induction and expansion. These findings suggest that HB disrupts the bioenergetic metabolism, and reduces intracellular survival potential of BC cells. Further molecular studies are needed to confirm and potentially apply these findings.