AIM: To study the role of hypermethylation in the loss of retinoic acid receptor beta(2) (RARbeta(2)) in esophageal squamous cell carcinoma (ESCC). METHODS: The role of hypermethylation in RARbeta(2) gene silencing in 6 ESCC cell lines was determined by methylation-specific PCR (MSP), and its methylation status was compared with RARbeta(2) mRNA expression by RT-PCR. The MSP results were confirmed by bisulfite sequencing of RARbeta(2) promoter regions. RESULTS: Methylation was detected in 4 of the 6 cell lines, and the expression of RARbeta(2) was markedly downregulated in 3 of the 4 methylated cell lines. The expression of RARbeta(2) was restored in one RARbeta(2) -downregulated cell line with the partial demethylation of promoter region of RARbeta(2) after 5-aza-2'-deoxycytidine (5-aza-dc) treatment. CONCLUSION: The methylation of the 5' region may play an important role in the downregulation of RARbeta(2) in some ESCC cell lines, suggesting that multiple mechanisms contribute to the loss of RARbeta(2) expression in ESCC cell lines. This study may have clinical applications for treatment and prevention of ESCC.
AIM: To study the role of hypermethylation in the loss of retinoic acid receptor beta(2) (RARbeta(2)) in esophageal squamous cell carcinoma (ESCC). METHODS: The role of hypermethylation in RARbeta(2) gene silencing in 6 ESCC cell lines was determined by methylation-specific PCR (MSP), and its methylation status was compared with RARbeta(2) mRNA expression by RT-PCR. The MSP results were confirmed by bisulfite sequencing of RARbeta(2) promoter regions. RESULTS: Methylation was detected in 4 of the 6 cell lines, and the expression of RARbeta(2) was markedly downregulated in 3 of the 4 methylated cell lines. The expression of RARbeta(2) was restored in one RARbeta(2) -downregulated cell line with the partial demethylation of promoter region of RARbeta(2) after 5-aza-2'-deoxycytidine (5-aza-dc) treatment. CONCLUSION: The methylation of the 5' region may play an important role in the downregulation of RARbeta(2) in some ESCC cell lines, suggesting that multiple mechanisms contribute to the loss of RARbeta(2) expression in ESCC cell lines. This study may have clinical applications for treatment and prevention of ESCC.
Authors: Tamotsu Kuroki; Francesco Trapasso; Sai Yendamuri; Ayumi Matsuyama; Hansjuerg Alder; Masaki Mori; Carlo M Croce Journal: Cancer Res Date: 2003-07-01 Impact factor: 12.701