ROS generation via NOX4 and its utility in the cytological diagnosis of urothelial carcinoma of the urinary bladder

BMC Urology

Research Article

Keiji Shimada¹  Noboru Konishi¹  Tomomi Fujii¹  Kiyohide Fujimoto²  Satoshi Anai² 

[1] Department of Pathology, Nara Medical University School of Medicine, 840 Shijo-cho, 634-8521, Kashihara city, Nara, Japan;Department of Urology, Nara Medical University School of Medicine, 840 Shijo-cho, 634-8521, Kashihara city, Nara, Japan;

关键词: Bladder Cancer;    Urothelial Carcinoma;    Urine Cytology;    Human Bladder Cancer;    Urothelial Carcinoma Cell;   

DOI  :  10.1186/1471-2490-11-22

 received in 2011-07-02, accepted in 2011-10-28,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundReactive oxygen species (ROS) production via NADPH oxidase (NOX) contributes to various types of cancer progression. In the present research, we examined the pathobiological role of NADPH oxidase (NOX)4-mediated generation of reactive oxygen species (ROS) in urothelial carcinoma (UC) of the urinary bladder, and demonstrated the utility of ROS labeling in urine cytology.MethodsNOX4 gene was silenced in vivo and in vitro by NOX4 siRNA transfection with or without atlocollagen. Cell cycle and measurement of ROS were analyzed by flowcytometry. Orthotopic implantation animal model was used in vivo experiment. NOX4 expression in urothelial carcinoma cells was observed by immunohistochemical analysis using surgical specimens of human bladder cancer. Urine cytology was performed after treatment with ROS detection reagents in addition to Papanicolaou staining.ResultsNOX4 was overexpressed in several UC cell lines and the NOX inhibitor, diphenylene iodonium reduced intracellular ROS and induced p16-dependent cell cycle arrest at the G1 phase. Moreover, silencing of NOX4 by siRNA significantly reduced cancer cell growth in vivo as assessed in an orthotopic mouse model. Immunohistochemistry demonstrated high expression of NOX4 in low grade/non-invasive and high grade/invasive UC including precancerous lesions such as dysplasia but not in normal urothelium. Then, we assessed the usefulness of cytological analysis of ROS producing cells in urine (ROS-C). Urine samples obtained from UC cases and normal controls were treated with fluorescent reagents labeling the hydrogen peroxide/superoxide anion and cytological atypia of ROS positive cells were analyzed. As a result, the sensitivity for detection of low grade, non-invasive UC was greatly increased (35% in conventional cytology (C-C) vs. 75% in ROS-C), and the specificity was 95%. Through ROS-C, we observed robust improvement in the accuracy of follow-up urine cytology for cases with previously diagnosed UC, especially in those with low grade/non-invasive cancer recurrence (0% in C-C vs. 64% in ROS-C).ConclusionsThis is the first report demonstrating that ROS generation through NOX4 contributes to an early step of urothelial carcinogenesis and cancer cell survival. In addition, cytology using ROS labeling could be a useful diagnostic tool in human bladder cancer.

【 授权许可】

Unknown   
© Shimada et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.