Morphologic and growth effects of tobacco-associated chemical carcinogens and smokeless tobacco extracts on human oral epithelial cells in culture

Oral Surg Oral Med Oral Pathol. 1993 Mar;75(3):323-32. doi: 10.1016/0030-4220(93)90145-t.


Epidemiologic studies show an increase in the use of smokeless tobacco but few in vitro studies have directly assessed the potential for smokeless tobacco-induced oral carcinogenesis. Oral keratinocytes were grown to 90% confluence from explants of human labial and gingival mucosa at 34 degrees C, 5% CO2 in defined media. Epithelial monolayers were subsequently subcultured and then treated for 1 hour with aqueous extracts of moist or leaf smokeless tobacco, or with 0.25 to 1.0 ng/ml of three common smokeless tobacco carcinogens: 4-(N-methyl-N-nitrosamino)-1-(3-pyridinyl)-1-butanone; N-nitrosonornicotine; and benzo(a)pyrene. Even though the controls and most treatment groups terminally differentiated, cells exposed to 4-(N-methyl-N-nitrosamino)-1-(3-pyridinyl)-1-butanone, N-nitrosonornicotine, and moist and dry extract continued to divide, maintained a differentiated phenotype for 8 1/2 to 10 weeks in culture, and displayed focal growth and morphologic changes suggestive of early stages in cell transformation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Carcinogens / toxicity*
  • Cell Division / drug effects
  • Cell Survival / drug effects
  • Cell Transformation, Neoplastic
  • Cells, Cultured
  • Fibroblasts / drug effects
  • Humans
  • Immunophenotyping
  • Mouth Mucosa / drug effects*
  • Nitrosamines / toxicity
  • Plants, Toxic*
  • Tobacco, Smokeless / toxicity*


  • Carcinogens
  • Nitrosamines
  • 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone
  • N'-nitrosonornicotine