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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1997-11-10
pubmed:abstractText
Selective delivery of lethal concentrations of drugs to tumors, allowing the latter to be eradicated without damage to other tissues, continues to be a major goal in cancer chemotherapy. Prodrugs (i.e. drugs that have been derivatized to prevent uptake into cells or interaction with targets), activated by enzyme-monoclonal antibody conjugates positioned at tumor sites, offer promise for achieving this objective. Methotrexate alpha-peptides (derivatives in which an amino acid is linked to the alpha-carboxyl group of the glutamate moiety) are ideal prodrugs, since they are not transported into cells and can be converted to the parent drug by carboxypeptidases. The L,L-diastereomer of MTX-alpha-Phe, synthesized in good yield by treatment of the p-nitrophenyl ester of 4-amino-4-deoxy-10-methylpteroic acid with Glu-alpha-Phe, was hydrolyzed readily by carboxypeptidase A (CP-A). Conjugate was prepared by derivatizing the enzyme and monoclonal antibody KS1/4 with linkers containing maleimide and sulfhydryl groups, respectively; interaction of these groups to form a stable thioether bond joined the proteins. When administered in vitro to UCLA-P3 human lung adenocarcinoma cells (ca. 5 x 10(4) antibody binding sites/cell) that had been pre-treated with the conjugate (whose antibody KS1/4 is targeted to these cells), and excess conjugate removed by extensive washing, MTX-Phe (ID50 = 6.3 x 10(-8) M) approached the toxicity of MTX (ID50 = 4.5 x 10(-8) M). In the absence of conjugate, MTX-Phe was much less toxic (ID50 = 2.2 x 10(-6) M).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0065-2571
pubmed:author
pubmed:issnType
Print
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
77-92
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Development of methotrexate alpha-peptides as prodrugs for activation by enzyme-monoclonal antibody conjugates.
pubmed:affiliation
Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037, USA.
pubmed:publicationType
Journal Article