Downregulation of glutathione S-transferase M1 protein in N-butyl-N-(4-hydroxybutyl)nitrosamine-induced mouse bladder carcinogenesis

• Published in: Toxicology and applied pharmacology 2014-09, Vol.279 (3), p.322-330
• Main Authors: Chuang, Jing-Jing, Dai, Yuan-Chang, Lin, Yung-Lun, Chen, Yang-Yi, Lin, Wei-Han, Chan, Hong-Lin, Liu, Yi-Wen
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Animals; Antimetabolites, Antineoplastic - pharmacology; Azacitidine - analogs & derivatives; Azacitidine - pharmacology; Biological and medical sciences; BIOLOGICAL MARKERS; Biomarker; BLADDER; Bladder cancer; Blotting, Western; Body Weight - drug effects; Butylhydroxybutylnitrosamine - toxicity; CAPILLARIES; CARCINOGENESIS; Carcinogenesis, carcinogens and anticarcinogens; CARCINOGENS; Carcinogens - toxicity; CARCINOMAS; Cell Line, Tumor; Chemical agents; CHEMOTHERAPY; Coloring Agents; CONNECTIVE TISSUE; Decitabine; DEOXYCYTIDINE; DIAGNOSTIC TECHNIQUES; DNA; DNA CpG methylation; Down-Regulation - drug effects; Electrophoresis, Gel, Two-Dimensional; Female; GLUTATHIONE; Glutathione S-transferase; Glutathione Transferase - biosynthesis; Glutathione Transferase - drug effects; Glutathione Transferase - genetics; Humans; Immunohistochemistry; KERATIN; LACTATE DEHYDROGENASE; Medical sciences; MESSENGER-RNA; METHYLATION; MICE; Mice, Inbred C57BL; Mucous Membrane - drug effects; Mucous Membrane - ultrastructure; MUCOUS MEMBRANES; Multiple tumors. Solid tumors. Tumors in childhood (general aspects); MYOSIN; Nephrology. Urinary tract diseases; NITROSAMINES; Protein 2D electrophoresis; Real-Time Polymerase Chain Reaction; RNA, Messenger - antagonists & inhibitors; RNA, Messenger - biosynthesis; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Toxicology; Tumors; Tumors of the urinary system; Urinary Bladder - pathology; Urinary Bladder Neoplasms - chemically induced; Urinary Bladder Neoplasms - genetics; Urinary Bladder Neoplasms - pathology; Urinary tract. Prostate gland
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2014.06.018

Bladder cancer is highly recurrent following specific transurethral resection and intravesical chemotherapy, which has prompted continuing efforts to develop novel therapeutic agents and early-stage diagnostic tools. Specific changes in protein expression can provide a diagnostic marker. In our present study, we investigated changes in protein expression during urothelial carcinogenesis. The carcinogen BBN was used to induce mouse bladder tumor formation. Mouse bladder mucosa proteins were collected and analyzed by 2D electrophoresis from 6 to 20weeks after commencing continuous BBN treatment. By histological examination, the connective layer of the submucosa showed gradual thickening and the number of submucosal capillaries gradually increased after BBN treatment. At 12-weeks after the start of BBN treatment, the urothelia became moderately dysplastic and tumors arose after 20-weeks of treatment. These induced bladder lesions included carcinoma in situ and connective tissue invasive cancer. In protein 2D analysis, the sequentially downregulated proteins from 6 to 20weeks included GSTM1, L-lactate dehydrogenase B chain, keratin 8, keratin 18 and major urinary proteins 2 and 11/8. In contrast, the sequentially upregulated proteins identified were GSTO1, keratin 15 and myosin light polypeptide 6. Western blotting confirmed that GSTM1 and NQO-1 were decreased, while GSTO1 and Sp1 were increased, after BBN treatment. In human bladder cancer cells, 5-aza-2′-deoxycytidine increased the GSTM1 mRNA and protein expression. These data suggest that the downregulation of GSTM1 in the urothelia is a biomarker of bladder carcinogenesis and that this may be mediated by DNA CpG methylation. •GSTM1 and NQO-1 proteins decreased in the mouse bladder mucosa after BBN treatment.•BBN induced GSTO1 and Sp1 protein expression in the mouse bladder mucosa.•5-Aza-2′-deoxycytidine increased GSTM1 mRNA and protein in human bladder cancer cell.•GSTM1 downregulation in the urothelia may be a biomarker of bladder carcinogenesis.