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The role of non-ras transforming genes in chemical carcinogenesis

C S Cooper1

  • 1Section of Molecular Carcinogenesis, Institute of Cancer Research, Sutton, Surrey, UK.

Environmental Health Perspectives
|June 1, 1991
PubMed

Insights

Chemically induced tumors often contain dominant transforming genes, including ras family members and other growth factor receptors like met and neu. These genes, activated by mutations or gene fusions, drive cancer development.

Area of Science:

  • Molecular Biology
  • Oncology
  • Genetics

Background:

  • Chemically induced tumors and cell lines frequently harbor dominant transforming genes.
  • The NIH 3T3 transfection-transformation assay is a key method for detecting these genes.
  • While ras family genes (H-ras, K-ras, N-ras) are common, other genes like met and neu are also implicated.

Purpose of the Study:

  • To identify and characterize dominant transforming genes in chemically induced malignancies.
  • To investigate the mechanisms of activation for non-ras transforming genes, specifically met and neu.

Main Methods:

  • DNA transfection experiments using NIH 3T3 mouse fibroblast cell line.
  • Analysis of activated met gene in a human cell line transformed by N-methyl-N'-nitro-N-nitrosoguanidine.
  • Characterization of activated neu gene in mouse nervous system tumors induced by N-ethyl-N-nitrosourea.
  • Cytogenetic studies and Southern analysis of DNA from neoplastic cells.

Main Results:

  • Activated met gene identified, encoding a growth factor receptor; activation involves a chimeric gene (met/trp).
  • Activated neu gene identified, encoding a growth factor receptor; activation involves a point mutation.
  • Demonstrated that genetic alterations are present in chemically induced malignancies.

Conclusions:

  • Chemically induced tumors contain diverse dominant transforming genes, including ras and non-ras proto-oncogenes.
  • Activation mechanisms for proto-oncogenes like met and neu involve gene fusion or point mutations.
  • These findings highlight the genetic basis of chemical carcinogenesis and identify novel oncogenes.

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