Frequent Epigenetic Suppression of Tumor Suppressor Gene Glutathione Peroxidase 3 by Promoter Hypermethylation and Its Clinical Implication in Clear Cell Renal Cell Carcinoma

International Journal of Molecular Sciences

Qianling Liu¹  Jie Jin¹  Jianming Ying²  Mengkui Sun¹  Yun Cui¹  Lian Zhang¹  Ben Xu¹  Yu Fan¹  Qian Zhang¹ 

[1] Department of Urology, Peking University First Hospital and Institute of Urology, National Research Center for Genitourinary Oncology, Beijing 100034, China; E-Mails:;Department of Pathology, Cancer Institute and Cancer Hospital, Peking Union Medical College (PUMC), Chinese Academy of Medical Sciences, Beijing 100021, China; E-Mail:

关键词: GPX3;    reactive oxygen species;    methylation;    tumor suppress gene;    clear cell renal cell carcinoma;   

DOI  :  10.3390/ijms160510636

来源: mdpi

【 摘 要 】

The goal of this study is to identify novel tumor suppressor genes silenced by promoter methylation in clear cell renal cell carcinoma (ccRCC) and discover new epigenetic biomarkers for early cancer detection. Reactive oxygen species (ROS) is a major cause of DNA damage that correlates with cancer initiation and progression. Glutathione peroxidase 3 (GPX3), the only known extracellular glycosylated enzyme of GPXs, is a major scavenger of ROS. GPX3 has been identified as a tumor suppressor in many cancers. However, the role of GPX3 in ccRCC remains unclear. This study aimed to investigate its epigenetic alteration in ccRCC and possible clinicopathological association. In our study, GPX3 methylation and down-regulation were detected in 5 out of 6 ccRCC cell lines and the GPX3 mRNA and protein expression level in ccRCC tumors was significantly lower than in adjacent non-malignant renal tissues (p < 0.0001). Treatment with 5-Aza-2'-deoxycytidine restored GPX3 expression in ccRCC cells. Aberrant methylation was further detected in 77.1% (162/210) of RCC primary tumors, but only 14.6% (7/48) in adjacent non-malignant renal tissues. GPX3 methylation status was significantly associated with higher tumor nuclear grade (p = 0.014). Thus, our results showing frequent GPX3 inactivation by promoter hypermethylation in ccRCC may reveal the failure in the cellular antioxidant system in ccRCC and may be associated with renal tumorigenesis. GPX3 tumor specific methylation may serve as a biomarker for early detection and prognosis prediction of ccRCC.

【 授权许可】

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© 2015 by the authors; licensee MDPI, Basel, Switzerland.