Expression of glutathione S-transferase M3 in clear cell renal cell carcinoma and its promoter CpG methylation
10.3724/SP.J.1008.2008.01273
- Author:
Qi WU
1
Author Information
1. Department of Urology
- Publication Type:Journal Article
- Keywords:
DNA methylation;
Glutathione transferase;
Kidney neoplasms;
Neoplasm metastasis
- From:
Academic Journal of Second Military Medical University
2010;29(11):1273-1278
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To examine the expression and promoter CpG island methylation of glutathione S-transferase M3 (GSTM3) gene in clear cell renal cell carcinoma (ccRCC), and to evaluate the relationship of expression, methylation of GSTM3 gene with the metastasis and oncogenesis of ccRCC. Methods: Using semi-quantitative RT-PCR technique, we examined GSTM3 expression in surgical specimens of 24 primary ccRCCs and adjacent non-malignant tissues, 14 metastatic ccRCCs and 2 ccRCC cell lines (RCC05-TXJ,RCC05-ZTJ) with different metastatic potentials. RCC05-TXJ cells were cultured in RPMI 1640 medium and treated with DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (5-Aza-CdR). Semi-quantitative RT-PCR was used to examine the expression of GSTM3 in response to 5-Aza-CdR treatment. Nested bisulfite sequencing PCR and DNA sequencing were used to analyze different methylation locuses in GSTM3 gene promoter in 10 primary ccRCCs and adjacent non-malignant tissues. We also examined the methylation level in 10 primary ccRCCs and the corresponding non-malignant tissues as well as 8 metastatic tissues by nested methylation-specific PCR. Results: Expression of GSTM3 gene in metastatic ccRCC cells (RCC05-TXJ) was lower than that in the non-metastatic ccRCC cells (RCC05-ZYJ). Down-regulation of GSTM3 gene expression was found in 17 of the 24 primary ccRCCs as compared with the non-malignant tissue. Expression of GSTM3 in the metastatic ccRCCs was lower than that in primary ccRCCs. 5-Aza-CdR treatment increased GSTM3 expression in RCC05-ZYJ. Methylation in GSTM3 promoter was found in 4 of 10 ccRCC tissues, 2 of 10 adjacent tissues, and 1 of 8 metastatic tissues. No significant difference was found between ccRCC and adjacent tissues (P = 0.628) or ccRCC and metastatic disease (P = 0.314) due to limit number of cases. Conclusion: Our findings support that promoter aberrant methylation is one of the major mechanisms of GSTM3 gene down-regulation in ccRCC. The preliminary identification of GSTM3 promoter methylation sites may provide a basis for further study.
