Linked Life Data

2162250

Source:http://linkedlifedata.com/resource/pubmed/id/2162250

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
1990-7-23
pubmed:abstractText
The effects of the lipid-soluble dihydrofolate reductase inhibitor, trimetrexate, on the inhibition of thymidylate biosynthesis as a result of perturbation in cellular folate pools in H35 hepatoma cells in vitro has been investigated. Exposure of the cultures to increasing concentrations of trimetrexate between 2 and 20 nM causes a marked reduction in de novo thymidylate biosynthesis and a concomitant decrease in (6R)5,10-methylenetetrahydropteroylpolyglutamate (5,10-CH2H4PteGlun) from 2.0-0.2 microM, respectively. This is accompanied by an increase in H2PteGlun from 1.2 microM in control cultures to 4.7 microM in cultures exposed to 20 nM trimetrexate. The dependency of de novo thymidylate biosynthesis on intracellular 5,10-CH2H4PteGlun in trimetrexate-treated cells is compared with (a) the relationship of thymidylate biosynthesis on intracellular levels of 5,10-CH2H4PteGlun in folate-depleted cells supplemented with increments of folic acid and (b) the substrate (5,10-CH2H4PteGlun) dependence of purified thymidylate synthase from the same source. All three results are nearly identical demonstrating that trimetrexate-dependent inhibition of de novo thymidylate biosynthesis is primarily a result of substrate depletion. These results coupled with the weak inhibitory properties of H2PteGlun for thymidylate synthase Ki = 5.0 microM) suggest that H2PteGlun accumulation is not the major determinant in inhibiting thymidylate synthase following trimetrexate inhibition but under certain conditions has the potential to enhance the inhibition caused by substrate depletion.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0008-5472
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
50
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3979-84
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Role of substrate depletion in the inhibition of thymidylate biosynthesis by the dihydrofolate reductase inhibitor trimetrexate in cultured hepatoma cells.
pubmed:affiliation
Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.