This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Breault, J. E. Articles by Dahiya, R. Search for Related Content PubMed PubMed Citation Articles by Breault, J. E. Articles by Dahiya, R.

Methylation of the -Catenin Gene Is Associated With Poor Prognosis of Renal Cell Carcinoma

¹ Department of Urology, Veterans Affairs Medical Center and University of California at San Francisco, San Francisco, California; Departments of ² Urology and ³ Biochemistry, Shimane University School of Medicine, Izumo, Japan; and ⁴ Department of Urology, Kagoshima University Faculty of Medicine, Kagoshima, Japan

Requests for reprints: Rajvir Dahiya, Urology Research Center (112F), Veterans Affairs Medical Center and University of California at San Francisco, 4150 Clement Street, San Francisco, CA 94121. Phone: 415-750-6964; Fax: 415-750-6639; E-mail: rdahiya{at}urol.ucsf.edu.

Purpose: -Catenin is a cell adhesion protein, and its functional loss is associated with tumor invasion and metastasis. We hypothesize that (1) promoter CpG methylation regulates the expression and function of the -catenin gene in renal cell carcinoma (RCC) and (2) methylation of the -catenin gene is associated with poor prognosis of RCC. To test these hypotheses, we analyzed the CpG methylation status of the -catenin gene and its correlation with clinical outcome in RCC.

Experimental Design: Genomic DNA and total RNA were extracted from three renal cancer cell lines (A498, Caki-1, and Caki-2) and 54 RCC tissue samples with their corresponding normal kidney tissue samples. Expression of -catenin gene was analyzed by reverse transcription-PCR and immunostaining. Promoter methylation was analyzed by two different methylation-specific PCR (MSP-A and MSP-B), and the results were verified by DNA sequencing.

Results: The demethylating agent (5-aza-2'-deoxycytidine) increased levels of mRNA transcript of the -catenin gene in three renal cancer cell lines. -Catenin mRNA and protein expression were significantly reduced in RCC samples compared with normal kidney samples, respectively (P < 0.05). MSP-A and MSP-B bands were detected in 45 of 54 (83.3%) and 49 of 54 (90.7%) RCC samples, respectively. In normal kidney, weak products of MSP-A and MSP-B were detected in 5 of 54 (9.3%) and 6 of 54 (11.1%) samples, respectively. Likewise, both MSP-A and MSP-B ratios were significantly higher in RCC samples compared with normal kidney samples, respectively (P < 0.01). Multivariate analysis revealed that the MSP-B ratio was a powerful and independent predictor superior to nuclear grade and Robson stage with respect to survival and disease progression (P = 0.029 and 0.0071, respectively). No mutations in the NH₂-terminal region of -catenin were found in this study.

Conclusion: Expression of -catenin is regulated by promoter CpG methylation, and the balance between methylated and unmethylated RCC cell populations could determine its functional role. Because the conventional nuclear grade and/or staging system have some limitations to predict precise clinical outcome, this is the first report demonstrating that promoter CpG methylation of -catenin can be an independent and superior predictor for survival and disease progression.

Key Words: -catenin • methylation • prognosis • renal cell carcinoma

This article has been cited by other articles:

				C. D E Margetts, M. Morris, D. Astuti, D. C Gentle, A. Cascon, F. E McRonald, D. Catchpoole, M. Robledo, H. P H Neumann, F. Latif, et al. Evaluation of a functional epigenetic approach to identify promoter region methylation in phaeochromocytoma and neuroblastoma Endocr. Relat. Cancer, September 1, 2008; 15(3): 777 - 786. [Abstract] [Full Text] [PDF]

				F. F. Costa, K. Le Blanc, and B. Brodin Concise Review: Cancer/Testis Antigens, Stem Cells, and Cancer Stem Cells, March 1, 2007; 25(3): 707 - 711. [Abstract] [Full Text] [PDF]

				F. Rahnama, F. Shafiei, P. D. Gluckman, M. D. Mitchell, and P. E. Lobie Epigenetic Regulation of Human Trophoblastic Cell Migration and Invasion Endocrinology, November 1, 2006; 147(11): 5275 - 5283. [Abstract] [Full Text] [PDF]

				T. Gastaldi, P. Bonvini, F. Sartori, A. Marrone, A. Iolascon, and A. Rosolen Plakoglobin is differentially expressed in alveolar and embryonal rhabdomyosarcoma and is regulated by DNA methylation and histone acetylation Carcinogenesis, September 1, 2006; 27(9): 1758 - 1767. [Abstract] [Full Text] [PDF]

				F. Christoph, S. Weikert, C. Kempkensteffen, H. Krause, M. Schostak, J. Kollermann, K. Miller, and M. Schrader Promoter Hypermethylation Profile of Kidney Cancer with New Proapoptotic p53 Target Genes and Clinical Implications Clin. Cancer Res., September 1, 2006; 12(17): 5040 - 5046. [Abstract] [Full Text] [PDF]