CpG Islands Methylation Status in SHP1 Gene Promoter Region in Gastric Cancer Cells

Objective To investigate the aberrant DNA methylation status of CpG islands in SHP1 gene promoter region in gastric cancer cells. Method CpG islands in the region of -1 000 bp-1 340 bp in transcription start sites of SHP1 gene were analyzed by Cpgplot software, and the primers of methylationspecific PCR (MSP) were designed by MethPrimer software. A new bisulfite-based MSP method was applied to detect the methylation status of SHP1 gene promoter region the limited gastric cancer cells. Bisulfite-modified DNA samples were amplified by MSP primers covering the CpG islands in SHP1 gene promoter region. The MSP products were purified cloned, which was subject to Sanger sequencing. Original and bisulfite modified partial sequences were compared. CpG loci methylation status was analyzed. Results Cpgplot displayed that MSP primers were located in SHP1 gene exon1 area which was close to the transcription initiation site. CpG islands length was > 200 bp, GC content was > 50%, and Obs/Exp was > 0.60. MSP detection showed that methylation-specific primer amplification was positive, whereas the unmethylation-specific primer amplification was negative, which revealed the region was highly methylated. Conclusion CpG islands in SHP1 gene promoter region are hypermethylated in gastric cancer cells.