Methylation-specific electrochemical biosensing strategy for highly sensitive and quantitative analysis of promoter methylation of tumor-suppressor gene in real sample

A handy and practical methylation-specific electrochemical biosensing strategy was developed by integrating bisulfite conversion and PCR amplification with high efficient electrochemical biosensor. The dual signal amplification of PCR and enzyme-catalyzed electrochemical sensing resulted in higher sensitivity of the proposed method. The primers for PCR and capture probes for amplicons binding were specifically designed to distinguish different CpG islands in the promoter regions of target gene, which further enhanced the specificity. The designed method showed very high sensitivity and specificity for DNA methylation analysis and was able to respond to about 8 copies of methylated promotor of secreted frizzled-related protein 2 (SFRP2) gene in 10,000 times of unmethylated genomic DNA. Moreover, the established biosensor was successfully verified for quantitative detection of SFRP2 promotor methylation in breast primary tumor tissues and subtlemonitor of SFRP2 promotor methylation status changes in real sample with the demethylating agent treatment This proposed strategy presented a simple and pragmatic platform toward high sensitive and quantitative detection promoter methylation of tumor-suppressor gene for early diagnosis and prognostic assessment of cancer, as well as monitoring response to therapeutic agents. (C) 2016 Published by Elsevier B.V.