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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1997-9-30
pubmed:abstractText
Nodularin is a new liver carcinogen possessing a potent tumor-promoting activity in rat liver, mediated through inhibition of protein phosphatases 1 and 2A, and a weak initiating activity. Since we previously reported evidence that nodularin up-regulated expression of the tumor necrosis factor alpha gene (TNF alpha) and early-response genes in rat liver after its i.p. administration, and since TNF alpha had tumor-promoting activity in vitro, it is possible that TNF alpha itself is involved in liver tumor promotion. We investigated whether hepatocytes themselves induce expression of the TNF alpha gene and early-response genes in primary cultured rat hepatocytes treated with nodularin. Like nodularin, microcystin-LR, which is another liver tumor promoter belonging to the okadaic acid class, strongly induced TNF alpha gene expression in rat hepatocytes, as well as TNF alpha release from those cells into the medium. On the other hand, 12-O-tetradecanoylphorbol-13-acetate, which has been reported to induce no tumor promotion in rat liver, induced no apparent expression of the TNF alpha gene in primary cultured rat hepatocytes. As for the expression of early-response genes, 1 microM nodularin or microcystin-LR induced expression of the c-jun, jun B, jun D, c-fos, fos B and fra-1 genes in the hepatocytes, and the expression of these genes was prolonged up to 24 h, suggesting mRNA stabilization induced by inhibition of protein phosphatases 1 and 2A. This paper presents new evidence that the TNF alpha gene and early-response genes were expressed in hepatocytes treated with a liver tumor promoter.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0171-5216
pubmed:author
pubmed:issnType
Print
pubmed:volume
123
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
413-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Expression of the tumor necrosis factor alpha gene and early response genes by nodularin, a liver tumor promoter, in primary cultured rat hepatocytes.
pubmed:affiliation
Saitama Cancer Center Research Institute, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't