Carcinogenesis, Vol 19, 897-903, Copyright © 1998 by Oxford University Press
T Tanaka, Y Nishiyama, K Okada, K Satoh, A Fukuda, K Uchida, T Osawa, H Hiai and S Toyokuni
An iron chelate, ferric nitrilotriacetate (Fe-NTA), induces renal proximal
tubular damage, a consequence of iron-catalysed Fenton-like reactions, that
finally leads to a high incidence of renal cell carcinoma (RCC) in rodents.
Glutathione S-transferase (GST) is a family of enzymes that play an
important role in detoxification of hydrophobic and electrophilic
molecules, and has been associated with putative preneoplastic foci of rat
hepatocarcinogenesis and chemotherapy- resistance of human cancers. Our
previous study revealed an induction of pi-class glutathione S-transferase
(Yp) mRNA in the kidney 3 h after administration of Fe-NTA. In the present
study, expression of GST isozymes were further investigated in the
Fe-NTA-induced RCCs of rats which are characterized by (1) high incidence
of metastasis and invasion, (2) high incidence of tumour-associated
mortality, and (3) possible involvement of reactive oxygen species in
carcinogenesis. In the Fe-NTA-induced RCCs, the levels of alpha-class GST
(Ya) mRNA and proteins were markedly decreased with no apparent change in
the copy number of the gene. In contrast, GST-Yp mRNA and proteins were
significantly increased in the RCCs while the total GST enzymatic activity
was decreased. Immunohistochemical analysis revealed intense staining of
GST-Yp not only in the primary RCCs and its metastatic sites, but also in
their non-tumorous part of proximal tubules. The contrastive expression of
GST isozymes in this renal carcinogenesis model suggests an alteration of
its transcription mechanisms and warrants further investigation of this
particular detoxifying enzyme from the viewpoint of reactive oxygen
species-induced carcinogenesis.
ARTICLES
Over-expression of glutathione S-transferase Yp isozyme and concomitant down-regulation of Ya isozyme in renal cell carcinoma of rats induced by ferric nitrilotriacetate
Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Japan.
![]()
CiteULike
Connotea
Del.icio.us What's this?