Linked Life Data

2833510

Source:http://linkedlifedata.com/resource/pubmed/id/2833510

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1988-5-18
pubmed:abstractText
Human HeLa cells and murine L(S) cells are highly sensitive to the cytocidal activity of tumor necrosis factor (TNF) when simultaneously treated with the inhibitor of protein synthesis cycloheximide. This cytocidal activity of TNF was inhibited up to 90% in both cell lines after a 15-60-min pretreatment with 3-10 ng/ml of phorbol 12-myristate 13-acetate (PMA). This inhibition was long lasting for HeLa cells but transient for L(S) cells. The protection afforded by PMA was most effective when the cells were pretreated with this phorbol ester, but it decreased when PMA was added together with TNF or after TNF addition. This finding suggested that PMA interfered with one of the early steps in the mechanism of action of TNF. A pretreatment with the calcium ionophore A23187 also reduced the cytocidal activity of TNF in both HeLa and L(S) cells to about the same extent. Treatment of these cells with either PMA or A23187 significantly decreased the binding of 125I-TNF to cell surface receptors. This decrease paralleled the time course and dose-response of the inhibition of cytocidal activity. In addition, treatment of HeLa cells with 1-oleyl-2-acetyl-glycerol (OAG) also induced a rapid loss of TNF binding capacity. Since OAG, PMA, and A23187 are all activators of protein kinase C (Ca2+/phospholipid-dependent enzyme), these results suggest that this kinase is involved in modulation of TNF sensitivity. Furthermore, depletion or inhibition of protein kinase C antagonized PMA-induced effects on TNF cytotoxicity and binding to receptors. Internalization of bound TNF was not significantly affected by PMA treatment, and Scatchard analysis of binding data indicated that PMA decreased TNF receptor binding affinity rather than the number of TNF-binding sites. These findings suggest that protein kinase C may have a physiological role in mediating TNF sensitivity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
263
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5686-92
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Tumor necrosis factor receptors and cytocidal activity are down-regulated by activators of protein kinase C.
pubmed:affiliation
Department of Biological Sciences, State University of New York, Albany 12222.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't