A microassay for measuring cytosine DNA methyltransferase activity during tumor progression

Steven A. Belinsky, Kristen J. Nikula, Stephen B. Baylin, Jean pierre Issa

Research output: Contribution to journalArticlepeer-review


The cytosine DNA methyltransferase (MT) enzyme, which catalyzes DNA methylation at CpG sites, is overexpressed at the mRNA level during the progressive stages of colon cancer. This paper describes the adaption of a sensitive microassay for determining MT enzyme activity during tumor progression in human colon and murine lung. MT activity was progressively elevated in mucosa from familial adenomatosis polyposis patients, mucosa adjacent to cancers, and in colonie adenocarcinomas when compared to colonie mucosa from control patients. In addition, the activity of this enzyme was increased in alveolar type II but not Clara cells isolated from A/J mice following carcinogen exposure and continued to increase during tumor progression. The use of a microassay for measuring MT activity indicates that changes in enzyme activity were in general agreement with previous findings of increased MT mRNA levels during colon cancer progression and also implicates the involvement of this pathway in lung cancer development.

Original languageEnglish (US)
Pages (from-to)335-340
Number of pages6
JournalToxicology Letters
Issue numberC
StatePublished - Dec 1995


  • Colon cancer
  • DNA methyltransferase activity
  • Lung cancer
  • Tumor progression
  • Type II cells

ASJC Scopus subject areas

  • Toxicology


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