Immunologically specific activation of a cephalosporin derivative of mitomycin C by monoclonal antibody beta-lactamase conjugates.
J Med Chem
; 40(17): 2788-92, 1997 Aug 15.
Article
em En
| MEDLINE
| ID: mdl-9276025
ABSTRACT
The syntheses of two cephalosporin derivatives 2 and 3 of mitomycin C (1) containing 7-phenylacetamido and 7-delta-carboxybutanamido side chains, respectively, are described. These compounds were prepared for evaluation as cephalosporin prodrugs capable of being activated by mAb-beta-lactamase conjugates. In vitro cytotoxicity assays performed on H2987 lung adenocarcinoma and clone 62 melanoma cell lines indicated that compound 2 was comparable in cytotoxicity to the parent drug. In an effort to improve upon the cytotoxic differential of 2, an alternative prodrug 3 containing a polar carboxyl group in the side chain of the cephalosporin moiety was prepared. Compound 3 consistently behaved as a prodrug and was approximately 40- and 10-fold less toxic than 1 toward H2987 and clone 62, respectively. Determination of kinetic constants for hydrolysis by beta-lactamase from Enterobacter cloacae P99 indicated kcat values of 476 +/- 170 and 248 +/- 15.1 s-1 for 2 and 3, respectively. The kcat/Km ratios for 2 and 3 were found to be approximately 9.7 and 2.1 microM/s, respectively. Comparison of these kcat/Km values with those obtained for similar cephalosporin derivatives of other antitumor agents demonstrated that compounds with delta-carboxybutanamido side chains generally have slightly diminished efficiency of enzymatic hydrolysis compared to the corresponding 7-phenylacetamido analog. It was also demonstrated that the less toxic prodrug 3 was activated in an immunologically specific manner by L6-F(ab')-beta-lactamase and 96.5-F(ab')-beta-lactamase conjugates, selective for H2987 and clone 62 cells, respectively.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Beta-Lactamases
/
Cefalosporinas
/
Mitomicinas
/
Anticorpos Monoclonais
Limite:
Humans
Idioma:
En
Revista:
J Med Chem
Assunto da revista:
QUIMICA
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Estados Unidos