Promoter methylation in the PTCH gene in cervical epithelial cancer and ovarian cancer tissue as studied by eight novel Pyrosequencing® assays

Int J Oncol. 2011 Mar;38(3):685-92. doi: 10.3892/ijo.2011.895. Epub 2011 Jan 3.

Abstract

DNA methylation status in the CpG sites of promoter regions in cancer-related genes, such as PTCH, has traditionally been investigated using either dye-terminator sequencing or methylation-specific PCR. We aimed to study the PTCH gene promoter methylation in gynecological cancers, with a method that gives a quantitative measure of the methylation status of the promoter region of the studied gene, and for this purpose, we designed novel Pyrosequencing-based assays. Bisulfite-treated genomic DNA (bsDNA) was amplified by standard PCR and applied to novel Pyrosequencing® assays, in order to measure the methylated fraction (%) at each CpG site of the PTCH gene promoter. We analyzed 22 squamous cell cervical cancer tissue specimens (11 with good and 11 with poor outcomes after radiotherapy) and 5 ovarian cancer tissue specimens matched with 5 normal ovarian tissue specimens. Six optimized PCR protocols which generated 8 Pyrosequencing assays covering 63 CpG sites in the promoter regions 1 and 2 as well as the previously unanalyzed promoter region 3 in the PTCH gene were developed. The 27 tumor tissue specimens and 5 normal tissues did not show any methylation within any of the 63 CpG sites. Our data suggest that methylation of the PTCH promoter is not a high-prevalence feature of squamous cell cervical cancer or ovarian cancer, but Pyrosequencing assays are a good method for studying promoter methylation.

MeSH terms

  • Base Sequence
  • CpG Islands
  • DNA Methylation* / physiology
  • Female
  • Gene Expression Regulation, Neoplastic
  • Gene Frequency
  • High-Throughput Nucleotide Sequencing / methods
  • Humans
  • Matched-Pair Analysis
  • Molecular Sequence Data
  • Neoplasms, Glandular and Epithelial / genetics*
  • Neoplasms, Glandular and Epithelial / pathology
  • Ovarian Neoplasms / genetics*
  • Ovarian Neoplasms / pathology
  • Patched Receptors
  • Patched-1 Receptor
  • Promoter Regions, Genetic* / genetics
  • Receptors, Cell Surface / genetics*
  • Receptors, Cell Surface / physiology
  • Sequence Analysis, DNA / methods*
  • Uterine Cervical Neoplasms / genetics*
  • Uterine Cervical Neoplasms / pathology

Substances

  • PTCH1 protein, human
  • Patched Receptors
  • Patched-1 Receptor
  • Receptors, Cell Surface