[Biosensors and Bioelectronics] Absolute quantification of DNA methylation using microfluidic chip-b
Hypermethylation of CpG islands in the promoter region of many tumor suppressor genes downregulates their expression and in a result promotes tumorigenesis. Therefore, detection of DNA methylation status is a convenient diagnostic tool for cancer detection. Here, we reported a novel method for the integrative detection of methylation by the microfluidic chip-based digital PCR. This method relies on methylation-sensitive restriction enzyme HpaII, which cleaves the unmethylated DNA strands while keeping the methylated ones intact. After HpaII treatment, the DNA methylation level is determined quantitatively by the microfluidic chip-based digital PCR with the lower limit of detection equal to 0.52%. To validate the applicability of this method, promoter methylation of two tumor suppressor genes (PCDHGB6 and HOXA9) was tested in 10 samples of early stage lung adenocarcinoma and their adjacent non-tumorous tissues. The consistency was observed in the analysis of these samples using our method and a conventional bisulfite pyrosequencing. Combining high sensitivity and low cost, the microfluidic chip-based digital PCR method might provide a promising alternative for the detection of DNA methylation and early diagnosis of epigenetics-related diseases.
Zhenhua Wua, b, Yanan Baia, b, Zule Chenga, b, Fangming Liua, Ping Wangc, Dawei Yangd, Gang Lie, Qinghui Jina, Hongju Maoa, , , Jianlong Zhaoa, , a State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China b University of Chinese Academy of Sciences, Beijing 100039, China c The Key Laboratory of Pharmacology and Medical Molecular Biology, Medical College, Henan University of Science and Technology, Luoyang 471023, China d Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, China e School of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China Received 17 February 2017, Revised 9 May 2017, Accepted 11 May 2017, Available online 12 May 2017