Expression profile of hydrogen sulfide and its synthases correlates with tumor stage and grade in urothelial cell carcinoma of bladder

Abstract

Background: Hydrogen sulfide (H2S) is a newly discovered gas transmitter. It is synthesized by cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (MPST). Endogenous hydrogen sulfide has never been studied in bladder cancer.

Purpose: We evaluated H2S production and its synthases expression levels in transitional cell carcinoma (urothelial cell carcinoma of bladder [UCB]) of human bladder tissue and cell lines.

Materials and methods: Immunostaining was performed in urothelial cell lines and bladder specimens from 94 patients with UCB of different stages/grades. The expression levels/activities of CBS, CSE, and MPST of specimens and cell lines were analyzed by image semiquantity assay, western blot, and a sulfur-sensitive electrode. We tried to find the correlation between hydrogen sulfide and its synthases with tumor stage in UCB. All experiments were repeated at least 3 times.

Results: Immunoreactivity for CBS, CSE, and MPST was detected in malignant uroepithelium and muscular layer of all tissues examined and cultured cells. The expression levels of CBS, CSE, and MPST were associated with UCB stage/grade. Muscle-invasive bladder cancer samples showed the highest production of H2S (52.6±2.91 nmol/[mg·min]) among all tested samples and EJ cells (transitional cell carcinoma, grade IIIshowed the highest production of H2S among all tested cell lines (53.3±7.02nmol/[mg·min]).

Conclusions: Protein levels and catalytic activities of CBS, CSE, and MPST increased with the increase of malignant degrees in human bladder tissues and human UCB cell lines. Our findings may promote the application of these novel enzymes to UCB diagnosis or treatment.

Keywords: 3-Mercaptopyruvate sulfurtransferase; Cystathionine β-synthase; Cystathionine γ-lyase; Hydrogen sulfide; Urothelial cell carcinoma of bladder.