Novel Inhibitors of Carboxypeptidase G2(CPG2):  Potential Use in Antibody-Directed Enzyme Prodrug Therapy

1999 ◽  
Vol 42 (6) ◽  
pp. 951-956 ◽  
Author(s):  
Tariq H. Khan ◽  
Ebun A. Eno-Amooquaye ◽  
Frances Searle ◽  
Pat J. Browne ◽  
Helen M. I. Osborn ◽  
...  
Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 625
Author(s):  
Mohammed S. Aldughaim ◽  
Fatimah Alsaffar ◽  
Michael D. Barker

Broad-spectrum cytotoxic drugs have been used in cancer therapy for decades. However, their lack of specificity to cancer cells often results in serious side-effects, limiting efficacy. For this reason, antibodies have been used to attempt to specifically target cytotoxic drugs to tumours. One such approach is antibody-directed enzyme prodrug therapy (ADEPT) which uses a tumour-directed monoclonal antibody, coupled to an enzyme, to convert a systemically administered non-toxic prodrug into a toxic one only at the tumour site. Among the main drawbacks of ADEPT is the immunogenicity of the antibody-enzyme complex, which is exacerbated by slow clearance due to size, hence limiting repeated administration. Additionally, the mono-specificity of the antibody could potentially result in drug resistance with repeated administration. We have identified a novel short peptide sequence, p700, derived from a human tissue inhibitor of metalloproteinases-3 (TIMP-3), which binds to and inhibits a number of tyrosine kinase growth factor receptors (VEGFRs1-3, FGFRs 1-4 and PDGFRα) which are known to be upregulated in many tumours and tumour vasculature. In this report, we fused p700 to His-tagged, codon-optimised, carboxypeptidase G2 (CPG2). CPG2 is a bacterial enzyme used in ADEPT, which activates potent nitrogen-mustard pro-drugs by removal of an inhibitory glutamic acid residue. Recombinant CPG2-p700 was highly expressed in Escherichia coli and successfully purified by nickel affinity chromatography. Biolayer interferometry showed that CPG2-p700 had a 100-fold increase in binding affinity for VEGFR2 compared with CPG2 alone and retained its catalytic activity, as determined by methotrexate cleavage. In the presence of CPG2-p700, the ZD2676P pro-drug showed significant cytotoxicity for 4T1 cells compared with prodrug alone or CPG2 alone. p700 is, therefore, a potentially useful alternative to monoclonal antibodies for enzyme pro-drug therapy and could equally be used for effective delivery of other cytotoxic drugs to tumour tissue.


2019 ◽  
Vol 10 (4) ◽  
pp. 45 ◽  
Author(s):  
Anderson ◽  
Hobbs ◽  
Gwenin ◽  
Ball ◽  
Bennie ◽  
...  

Directed enzyme prodrug therapy (DEPT) involves the delivery of a prodrug-activating enzyme to a solid tumour site, followed by the subsequent activation of an administered prodrug. One of the most studied enzyme–prodrug combinations is the nitroreductase from Escherichia coli (NfnB) with the prodrug CB1954 [5-(aziridin-1-yl)-2,4-dinitro-benzamide]. One of the major issues faced by DEPT is the ability to successfully internalize the enzyme into the target cells. NfnB has previously been genetically modified to contain cysteine residues (NfnB-Cys) which bind to gold nanoparticles for a novel DEPT therapy called magnetic nanoparticle directed enzyme prodrug therapy (MNDEPT). One cellular internalisation method is the use of cell-penetrating peptides (CPPs), which aid cellular internalization of cargo. Here the cell-penetrating peptides: HR9 and Pep-1 were tested for their ability to conjugate with NfnB-Cys. The conjugates were further tested for their potential use in MNDEPT, as well as conjugating with the delivery vector intended for use in MNDEPT and tested for the vectors capability to penetrate into cells.


ChemInform ◽  
2006 ◽  
Vol 37 (29) ◽  
Author(s):  
Christian Asche ◽  
Pascal Dumy ◽  
Daniele Carrez ◽  
Alain Croisy ◽  
Martine Demeunynck

Author(s):  
Cindy Yeoh Shin Ly ◽  
Anil Philip Kunnath

Gene-directed enzyme prodrug therapy (GDEPT) is an advanced cancer therapy that has potential use against localized and metastasized cancer. This strategy aims to improve the limitations of chemotherapy and existing cancer treatments by specific gene delivery, which allows the conversion of systemically administered nontoxic prodrugs to active chemotherapeutic drugs inside the target tumor cells, thereby resulting in a significant therapeutic index by introducing high concentrations of cytotoxic compounds to the tumor cells while limiting the systemic toxicity. The main attraction of GDEPT is by expanding the toxicity to adjacent non-expressing target cancer cells through local and distal bystander effects, leading to tumor regression. This review focused on the application of the six main GDEPT systems for treating cancer, including herpes simplex virus thymidine kinase (HSV-TK) with ganciclovir (GCV), cytosine deaminase (CD) from bacteria or yeast with 5-fluorocytosine (5-FC), E. coli nitroreductase (NfsB) with 5-(aziridin-1-yl)-2,4- initrobenzamide (CB1954), hepatic cytochrome P4l50 (CYP450) with cyclophosphamide (CPA), purine nucleoside phosphorylase (PNP) from E. coli with 6-methylpurine deoxyriboside (MEP), and bacterial carboxypeptidase G2 (CPG2) with 4-[(2-chloroethyl)(2-mesloxyethyl)amino] benzoyl-L-glutamic acid (CMDA). In each system, the mechanism of action, clinical trials for the past decades, limitations, and areas that need improvement are discussed.


2000 ◽  
Vol 16 (1-2) ◽  
pp. 53-62 ◽  
Author(s):  
K. A. Chester ◽  
J. Bhatia ◽  
G. Boxer ◽  
S. P. Cooke ◽  
A. A. Flynn ◽  
...  

Single chain Fv antibodies (sFvs) have been produced from filamentous bacteriophage libraries obtained from immunised mice. MFE-23, the most characterised of these sFvs, is reactive with carcinoembryonic antigen (CEA), a glycoprotein that is highly expressed in colorectal adenocarcinomas. MFE-23 has been expressed in bacteria and purified in our laboratory for two clinical trials; a gamma camera imaging trial using123I-MFE-23 and a radioimmunoguided surgery trial using125I-MFE-23, where tumour deposits are detected by a hand-held probe during surgery. Both these trials show MFE-23 is safe and effective in localising tumour deposits in patients with cancer. We are now developing fusion proteins which use MFE-23 to deliver a therapeutic moiety; MFE-23::CPG2 targets the enzyme carboxypeptidase G2 (CPG2) for use in the ADEPT (antibody directed enzyme prodrug therapy) system and MFE::TNFα aims to reduce sequestration and increase tumor concentrations of systemically administered TNFα.


2006 ◽  
Vol 16 (7) ◽  
pp. 1990-1994 ◽  
Author(s):  
Christian Asche ◽  
Pascal Dumy ◽  
Danièle Carrez ◽  
Alain Croisy ◽  
Martine Demeunynck

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