Lack of correlated expression between the glutathione S-transferase P-form and the oncogene products c-Jun and c-Fos in rat tissues and preneoplastic hepatic foci.
Since the expression of glutathione S-transferase P-form (GST-P) has been suggested from in vitro studies to be partly regulated by the oncogene product, c-Jun and c-Fos, their distributions were compared in normal rat tissues and preneoplastic hepatic lesions induced by the Solt-Farber protocol. Immunohistochemically demonstrated GST-P protein was positively correlated with expression of both c-Jun and c-Fos in the epidermis of the skin and the smooth muscle of adult lung and with either c-Jun or c-Fos respectively in the bile ducts and bronchial epithelium. However, GST-P expression was also observed in proximal and distal straight segments of the kidney and other tissues negative for c-Jun and c-Fos and both c-Jun and c-Fos were present in the renal proximal and distal convoluted tubules, where GST-P was lacking. Thus, the localization of GST-P was in some cases clearly separable from those of c-Jun or c-Fos. GST-P was found to be focally expressed from an early stage of hepatocarcinogenesis, when c-Jun was not detectable. At later stages, this oncogene product was stained in 35.7% of GST-P-positive foci, with a clear relation to the degree of GST-P staining. Since GST-P is not always accompanied by appreciable c-Jun or c-Fos, these oncogene products are apparently not prerequisites for its expression. However, c-Jun may be partly responsible for maintaining high levels of GST-P in hepatic foci at later stages of hepatocarcinogenesis.
Suzuki
S
S
Second Department of Biochemistry, Hirosaki University School of Medicine, Japan.
Satoh
K
K
Nakano
H
H
Hatayama
I
I
Sato
K
K
Tsuchida
S
S
D000818:Animals; D000918:Antibody Specificity; D005982:Glutathione Transferase / Q000096:biosynthesis* / Q000235:genetics; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008114:Liver Neoplasms, Experimental / Q000201:enzymology / Q000235:genetics*; D008297:Male; D011230:Precancerous Conditions / Q000201:enzymology / Q000235:genetics*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis* / Q000235:genetics; D016755:Proto-Oncogene Proteins c-jun / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology
D007527:Isoenzymes; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase