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Oncogene Expression in Cell Lines Derived From Rat Tracheal Implants Exposed In Vivo to 7,12‐Dimethylbenz[ a ]anthracene
Author(s) -
Cosma Greg N.,
Marchok Ann C.,
Garte Seymour J.
Publication year - 1989
Publication title -
molecular carcinogenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 97
eISSN - 1098-2744
pISSN - 0899-1987
DOI - 10.1002/mc.2940020507
Subject(s) - biology , 7,12 dimethylbenz[a]anthracene , in vivo , oncogene , microbiology and biotechnology , cancer research , cell , genetics , cell cycle , gene , carcinogenesis , dmba
Expression of four oncogenes and two keratin genes was determined in rat tracheal epithelial cell lines derived from tracheal implants exposed in vivo to 7,12‐dimethylbenz[ a ]anthracene. Cell lines were grouped into four stages of neoplastic progression based on phenotypic markers in order to correlate oncogene expression with stage of malignancy. Northern analysis of RNA revealed a significantly enhanced expression of the c‐ myc oncogene in the most tumorigenic or tumor‐derived cell lines, whereas preneoplastic cells expressed approximately fivefold less transcript. Southern analysis of tracheal cell DNA did not demonstrate amplification of the c‐ myc gene in any of the positive cell lines. In contrast to c‐ myc , other oncogenes such as ras and fos were expressed in all cell lines, as well as in control cell cultures, to a similar extent. Patterns of differentiation were examined in these epithelial cell lines by determining the expression of two distinct keratin genes, KA‐1 and KB‐2 . Both malignant and preneoplastic cells expressed the KB‐2 gene at variably high levels, whereas the expression of the KA‐1 keratin was barely detectable in any of the cell lines. The stage‐specific expression of the c‐ myc oncogene in these tracheal cell lines suggests a correlation between the regulation of certain oncogenes and neoplastic progression in this model of respiratory carcinogenesis.