nitrophenols and Urinary-Bladder-Neoplasms

Aromatic amines can be metabolized by N-acetylation and N-hydroxylation to hydroxamic acids; these subsequently are conjugated to form the N,O-sulfonate and N,O-glucuronide conjugates. The N,O-sulfonates are highly labile metabolites that generate reactive intermediates involved in the covalent binding of the parent compound to protein, RNA and DNA, as well as to low molecular compounds like glutathione. This paper discusses methods used to decrease sulfation in vivo, and thereby to enhance the formation of the more stable N,O-glucuronides from N-hydroxy-2-acetylaminofluorene and N-hydroxy-4-acetylamino-4'-fluorobiphenyl. Acetaminophen pretreatment decreases the sulfate availability, but results in many side effects that complicate the analysis of the results. An 8% casein diet reduces the sulfate availability in the rat to approximately 20% of control and thus offers an effective approach to decrease sulfation. The most effective selective inhibition of sulfation is by pentachlorophenol, which very strongly reduces N,O-sulfonation of both hydroxamic acids, and selectively inhibits the formation of DNA adducts that have retained the N-acetyl group. This inhibitor and the related 2,6-dichloro-4-nitrophenol can be employed to study the role of sulfation of hydroxamic acids in initiation and promotion of tumor formation by aromatic amines.

Topics: Acetaminophen; Amines; Animals; Binding Sites; Biological Availability; Carcinogens; Diet; Glucuronates; Glutathione; Hydroxamic Acids; Nitrophenols; Pentachlorophenol; Rats; Sulfates; Urinary Bladder Neoplasms

ABT‑737 is a recently reported inhibitor of members of the Bcl‑2 family of apoptosis regulators. However, to the best of our knowledge, its necroptosis‑inducing function in bladder cancer has not yet been researched. Thus, the present study aimed to investigate whether this Bcl‑2 family inhibitor can induce both apoptosis and necroptosis of urothelial carcinoma cells. The proliferation and survival of urothelial carcinoma cell lines treated with a combination of both Z‑VAD‑FMK as a pan‑caspase inhibitor and ABT‑737 were assessed in vitro. Z‑DNA binding protein 1 (ZBP1), receptor‑interacting protein (RIP)1 and RIP3 were knocked down using small interfering RNA in urothelial carcinoma cell lines. The protein expression levels of ZBP1, RIP1 and RIP3 following cell transfection were measured via western blot analysis. Cell viability was determined using an MTT assay. Cell invasion was examined using cell invasion assays. The expression levels of necroptosis‑related proteins, high mobility group box 1, ZBP1, mixed‑lineage kinase domain‑like protein (MLKL) and RIP3, were measured via western blotting. It was found that ABT‑737 inhibited the proliferation and invasion of bladder cancer cells by inducing cell necrosis. The data demonstrated that ZBP1 and RIP3 have main roles in the cell necrosis induced by ABT‑737. In addition, RIP3 and ZBP1, without interacting with RIP1, directly induced MLKL‑mediated programmed cell necrosis. Thus, understanding how urothelial carcinoma cells react to Bcl‑2 family inhibitors may accelerate the discovery of drugs to treat bladder cancer.

Topics: Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Carcinoma; Cell Line, Tumor; Humans; Necroptosis; Nitrophenols; Nuclear Pore Complex Proteins; Piperazines; Protein Kinases; Proto-Oncogene Proteins c-bcl-2; Receptor-Interacting Protein Serine-Threonine Kinases; RNA-Binding Proteins; Sulfonamides; Urinary Bladder Neoplasms

Although health hazards of 4-nitrophenol (PNP) exposure have been reported, the adverse effects of PNP exposure on cancer biological features are still unknown. We investigated the effects of administration of PNP in T24 human bladder cancer cells. The results showed that PNP exposure promoted cellular proliferation, migration and invasion, inhibited adhesion and apoptosis in vitro. Using quantitative real-time PCR, we found that (1) the mRNA expression levels of cell-cycle regulators PCNA, cyclin D1 and COX-2 were increased in PNP-treated cells compared to controls, however, that of pro-apoptotic gene Bax was decreased; (2) the expression level of EMT-associated gene E-cadherin was decreased in PNP-treated cells, whereas those of N-cadherin, vimentin, snail, and slug were increased; (3) the expression levels of cancer-promoting genes HIF-1, IL-1β, VEGFα and K-Ras were enhanced, but those of tumor suppressors p53, PTEN and BRCA were decreased. There was a positive association between PNP exposure times and the promotion effects. Finally, we found that the expression level of PPARγ (γ1 isoform) was increased in PNP-treated T24 cells. GW9662, a specific PPARγ antagonist, attenuated PNP-induced cell migration and invasion. These findings indicate that PNP exposure may promote bladder cancer growth and progression involving PPARγ signaling. PPARγ is a potential target for development of novel intervention study on environment pollution. Environ. Mol. Mutagen. 61:316-328, 2020. © 2019 Wiley Periodicals, Inc.

Topics: Carcinogens, Environmental; Cell Line, Tumor; Cell Movement; Cell Proliferation; Disease Progression; Endocrine Disruptors; Epithelial-Mesenchymal Transition; Humans; Neoplasm Invasiveness; Nitrophenols; Urinary Bladder Neoplasms

BAG3 is overexpressed in several malignancies and mediates a non-canonical, selective form of (macro)autophagy. By stabilizing pro-survival Bcl-2 proteins in complex with HSP70, BAG3 can also exert an apoptosis-antagonizing function. ABT-737 is a high affinity Bcl-2 inhibitor that fails to target Mcl-1. This failure may confer resistance in various cancers.. Urothelial cancer cells were treated with the BH3 mimetics ABT-737 and (-)-gossypol, a pan-Bcl-2 inhibitor which inhibits also Mcl-1. To clarify the importance of the core autophagy regulator ATG5 and BAG3 in ABT-737 treatment, cell lines carrying a stable lentiviral knockdown of ATG5 and BAG3 were created. The synergistic effect of ABT-737 and pharmaceutical inhibition of BAG3 with the HSF1 inhibitor KRIBB11 or sorafenib was also evaluated. Total cell death and apoptosis were quantified by FACS analysis of propidium iodide, annexin. Target protein analysis was conducted by Western blotting.. Knockdown of BAG3 significantly downregulated Mcl-1 protein levels and sensitized urothelial cancer cells to apoptotic cell death induced by ABT-737, while inhibition of bulk autophagy through depletion of ATG5 had no discernible effect on cell death. Similar to knockdown of BAG3, pharmacological targeting of the BAG3/Mcl-1 pathway with KRIBB11 was capable to sensitize both cell lines to treatment with ABT-737.. Our results show that BAG3, but not bulk autophagy has a major role in the response of bladder cancer cells to BH3 mimetics. They also suggest that BAG3 is a suitable target for combined therapies aimed at synergistically inducing apoptosis in bladder cancer.

Topics: Adaptor Proteins, Signal Transducing; Apoptosis; Apoptosis Regulatory Proteins; Biphenyl Compounds; Blotting, Western; Butylated Hydroxytoluene; Carcinoma, Transitional Cell; Cell Line, Tumor; DNA, Neoplasm; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Urinary Bladder Neoplasms