Hypomethylation and hypoexpression of human CYP2E1 gene in lung tumors

Biochem Biophys Res Commun. 1994 Dec 15;205(2):1086-92. doi: 10.1006/bbrc.1994.2777.


We have demonstrated the presence of CYP2E1 protein in a catalytically active form in lung tumors, differences being observed between the tumors and normal tissues from the same patients. Indeed, a higher microsomal CYP2E1 N-nitrosodimethylamine (NDMA) demethylase activity was present in normal tissues compared to tumors and was accompanied by corresponding change in CYP2E1 protein concentration, as shown by Western blot analysis. The catalytic activity among tumors differed from that among normal tissues with statistical significance of p < 0.01. CYP2E1 mRNA was present in lung tumors and less expressed compared to normal tissues from the same individuals. In order to understand the regulation of CYP2E1 gene expression, we studied the methylation status of the CYP2E1 gene in human lung tumors and normal tissues from the same patients and observed that a hypomethylation was associated with a hypoexpression of the CYP2E1 gene in lung tumors.

Publication types

  • Comparative Study

MeSH terms

  • Base Sequence
  • Blotting, Western
  • Carcinoma, Squamous Cell / enzymology*
  • Carcinoma, Squamous Cell / genetics
  • Cytochrome P-450 CYP2E1
  • Cytochrome P-450 Enzyme System / analysis
  • Cytochrome P-450 Enzyme System / biosynthesis*
  • DNA / chemistry
  • DNA / isolation & purification
  • DNA Primers
  • DNA, Neoplasm / chemistry
  • DNA, Neoplasm / isolation & purification
  • Gene Expression*
  • Humans
  • Lung / enzymology*
  • Lung Neoplasms / enzymology*
  • Lung Neoplasms / genetics
  • Male
  • Methylation
  • Microsomes / enzymology*
  • Molecular Sequence Data
  • Oxidoreductases, N-Demethylating / analysis
  • Oxidoreductases, N-Demethylating / biosynthesis*
  • Polymerase Chain Reaction
  • RNA, Messenger / analysis
  • RNA, Messenger / biosynthesis
  • Smoking


  • DNA Primers
  • DNA, Neoplasm
  • RNA, Messenger
  • DNA
  • Cytochrome P-450 Enzyme System
  • Cytochrome P-450 CYP2E1
  • Oxidoreductases, N-Demethylating