- Synthesis and biological characterization of protease-activated prodrugs of doxazolidine
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Doxazolidine (doxaz) is a new anthracycline anticancer agent. While structurally similar to doxorubicin (dox), doxaz acts via a distinct mechanism to selectively enhance anticancer activity over cardiotoxicity, the most significant clinical impediment to successful anthracycline treatment. Here, we describe the synthesis and characterization of a prodrug platform designed for doxaz release mediated by secreted proteolytic activity, a common association with invasiveness and poor prognosis in cancer patients. GaFK-Doxaz is hydrolyzable by the proteases plasmin and cathepsin B, both strongly linked with cancer progression, as well as trypsin. We demonstrate that activation of GaFK-Doxaz releases highly potent doxaz that powerfully inhibits the growth of a wide variety of cancer cells (average IC50 of 8 nM). GaFK-Doxaz is stable in human plasma and is poorly membrane permeable, thereby limiting activation to locally secreted proteolytic activity and reducing the likelihood of severe side effects.
- Barthel, Benjamin L.,Rudnicki, Daniel L.,Kirby, Thomas Price,Colvin, Sean M.,Burkhart, David J.,Koch, Tad H.
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p. 6595 - 6607
(2012/10/07)
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- Synthesis and biological evaluation of novel prodrugs of anthracyclines for selective activation by the tumor-associated protease plasmin
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New prodrugs of daunorubicin and doxorubicin designed for selective activation by the serine protease plasmin are described. The low toxic prodrugs 3, 4, and 5 are converted to the corresponding cytotoxic drugs upon proteolysis by the tumor-associated protease plasmin. Application of a self- eliminating spacer was essential for enzyme activation. A prodrug containing a chloro-substituted spacer was synthesized with the aim of enhancing the rate of conversion by plasmin. All prodrugs were highly stable in buffer solution and in serum and on the average 15-fold less cytotoxic than the parent drugs in seven human tumor cell lines. A marked in vitro selectivity was demonstrated by incubation of the doxorubicin prodrugs with a plasmin generating MCF-7 breast cancer cell line transfected with urokinase-type plasminogen activator (u-PA) in comparison with the nontransfected nonplasmin generating cell line. Prodrugs 4 and 5 showed the same cytotoxic effect as the free parent drug doxorubicin in the u-PA transfected cells, indicating complete conversion of the prodrug by plasmin. Addition of the plasmin inhibitor Trasylol drastically increased the ID50 values in the u-PA transfected MCF-7 cells for both prodrugs 4 and 5.
- De Groot, Franciscus M. H.,De Bart, Anton C. W.,Verheijen, Jan H.,Scheeren, Hans W.
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p. 5277 - 5283
(2007/10/03)
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- Cathepsin B-sensitive dipeptide prodrugs. 1. A model study of structural requirements for efficient release of doxorubicin
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A series of lysosomal protease-sensitive peptides attached to doxorubicin (DOX) was prepared as model substrates for internalizing anticancer immunoconjugates and potential antimetastasis prodrugs. Rates of cathepsin B-mediated release of free drug was measured for each, and human plasma stabilities for representative examples.
- Dubowchik, Gene M.,Firestone, Raymond A.
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p. 3343 - 3346
(2007/10/03)
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