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Moradbeygi F, Ghasemi Y, Farmani AR, Hemmati S. Glucarpidase (carboxypeptidase G2): Biotechnological production, clinical application as a methotrexate antidote, and placement in targeted cancer therapy. Biomed Pharmacother 2023; 166:115292. [PMID: 37579696 DOI: 10.1016/j.biopha.2023.115292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/30/2023] [Accepted: 08/04/2023] [Indexed: 08/16/2023] Open
Abstract
Patients receiving high-dose methotrexate (HDMTX) for malignancies are exposed to diverse complications, including nephrotoxicity, hepatotoxicity, mucositis, myelotoxicity, neurological symptoms, and death. Glucarpidase is a recombinant carboxypeptidase G2 (CPG2) that converts MTX into nontoxic metabolites. In this study, the role of vector type, gene optimization, orientation, and host on the expression of CPG2 is investigated. The effectiveness of various therapeutic regimens containing glucarpidase is classified and perspectives on the dose adjustment based on precision medicine are provided. Conjugation with cell-penetrating peptides, human serum albumin, and polymers such as PEG and dextran for delivery, higher stability, and production of the biobetter variants of CPG2 is highlighted. Conjugation of CPG2 to F(ab՜)2 or scFv antibody fragments against tumor-specific antigens and the corresponding prodrugs for tumor-targeted drug delivery using the antibody-directed enzyme prodrug therapy (ADEPT) is communicated. Trials to reduce the off-target effects and the possibility of repeated ADEPT cycles by adding pro-domains sensitive to tumor-overexpressed proteases, antiCPG2 antibodies, CPG2 mutants with immune-system-unrecognizable epitopes, and protective polymers are reported. Intracellular cpg2 gene expression by gene-directed enzyme prodrug therapy (GDEPT) and the concerns regarding the safety and transfection efficacy of the GDEPT vectors are described. A novel bifunctional platform using engineered CAR-T cell micropharmacies, known as Synthetic Enzyme-Armed KillER (SEAKER) cells, expressing CPG2 to activate prodrugs at the tumor niche is introduced. Taken together, integrated data in this review and recruiting combinatorial strategies in novel drug delivery systems define the future directions of ADEPT, GDEPT, and SEAKER cell therapy and the placement of CPG2 therein.
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Affiliation(s)
- Fatemeh Moradbeygi
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Younes Ghasemi
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran; Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ahmad Reza Farmani
- Tissue Engineering Department, School of Advanced Technologies in Medicine, Fasa University of Medical Sciences, Fasa, Iran
| | - Shiva Hemmati
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran; Biotechnology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
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2
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Jain S, Aresu L, Comazzi S, Shi J, Worrall E, Clayton J, Humphries W, Hemmington S, Davis P, Murray E, Limeneh AA, Ball K, Ruckova E, Muller P, Vojtesek B, Fahraeus R, Argyle D, Hupp TR. The Development of a Recombinant scFv Monoclonal Antibody Targeting Canine CD20 for Use in Comparative Medicine. PLoS One 2016; 11:e0148366. [PMID: 26894679 PMCID: PMC4760772 DOI: 10.1371/journal.pone.0148366] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 01/19/2016] [Indexed: 01/08/2023] Open
Abstract
Monoclonal antibodies are leading agents for therapeutic treatment of human diseases, but are limited in use by the paucity of clinically relevant models for validation. Sporadic canine tumours mimic the features of some human equivalents. Developing canine immunotherapeutics can be an approach for modeling human disease responses. Rituximab is a pioneering agent used to treat human hematological malignancies. Biologic mimics that target canine CD20 are just being developed by the biotechnology industry. Towards a comparative canine-human model system, we have developed a novel anti-CD20 monoclonal antibody (NCD1.2) that binds both human and canine CD20. NCD1.2 has a sub-nanomolar Kd as defined by an octet red binding assay. Using FACS, NCD1.2 binds to clinically derived canine cells including B-cells in peripheral blood and in different histotypes of B-cell lymphoma. Immunohistochemical staining of canine tissues indicates that the NCD1.2 binds to membrane localized cells in Diffuse Large B-cell lymphoma, Marginal Zone Lymphoma, and other canine B-cell lymphomas. We cloned the heavy and light chains of NCD1.2 from hybridomas to determine whether active scaffolds can be acquired as future biologics tools. The VH and VL genes from the hybridomas were cloned using degenerate primers and packaged as single chains (scFv) into a phage-display library. Surprisingly, we identified two scFv (scFv-3 and scFv-7) isolated from the hybridoma with bioactivity towards CD20. The two scFv had identical VH genes but different VL genes and identical CDR3s, indicating that at least two light chain mRNAs are encoded by NCD1.2 hybridoma cells. Both scFv-3 and scFv-7 were cloned into mammalian vectors for secretion in CHO cells and the antibodies were bioactive towards recombinant CD20 protein or peptide. The scFv-3 and scFv-7 were cloned into an ADEPT-CPG2 bioconjugate vector where bioactivity was retained when expressed in bacterial systems. These data identify a recombinant anti-CD20 scFv that might form a useful tool for evaluation in bioconjugate-directed anti-CD20 immunotherapies in comparative medicine.
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Affiliation(s)
- Saurabh Jain
- University of Edinburgh, Institute of Genetic and Molecular Medicine and School of Veterinary Medicine, Edinburgh, EH4 2XR, United Kingdom
| | - Luca Aresu
- Dipartimento di Biomedicina Comparata e Alimentazione (BCA) Department of Comparative Biomedicine and Food Science, Università di Padova 35020 Legnaro (PD), Italy
| | - Stefano Comazzi
- Dipartimento di Scienze Veterinarie e Sanità Pubblica, Università degli Studi di Milano, via Celoria 10, 20133 Milano, Italy
| | - Jianguo Shi
- University of Edinburgh, Institute of Genetic and Molecular Medicine and School of Veterinary Medicine, Edinburgh, EH4 2XR, United Kingdom
| | - Erin Worrall
- University of Edinburgh, Institute of Genetic and Molecular Medicine and School of Veterinary Medicine, Edinburgh, EH4 2XR, United Kingdom
| | - John Clayton
- Mologic, Ltd, Bedford Technology Park, Thurleigh, Bedford, MK44 2YP, United Kingdom
| | - William Humphries
- Mologic, Ltd, Bedford Technology Park, Thurleigh, Bedford, MK44 2YP, United Kingdom
| | - Sandra Hemmington
- Mologic, Ltd, Bedford Technology Park, Thurleigh, Bedford, MK44 2YP, United Kingdom
| | - Paul Davis
- Mologic, Ltd, Bedford Technology Park, Thurleigh, Bedford, MK44 2YP, United Kingdom
| | - Euan Murray
- University of Edinburgh, Institute of Genetic and Molecular Medicine and School of Veterinary Medicine, Edinburgh, EH4 2XR, United Kingdom
- INSERM Unité 940, Institut de Génétique Moléculaire, Université Paris 7, Hôpital St Louis, 27 rue Juliette Dodu, Paris, France
| | - Asmare A. Limeneh
- Bahit Dar University College of Medicine and Health Sciences Department of Medical Biochemistry and Molecular Biology, Bahir Dar, Ethiopia
| | - Kathryn Ball
- University of Edinburgh, Institute of Genetic and Molecular Medicine and School of Veterinary Medicine, Edinburgh, EH4 2XR, United Kingdom
| | - Eva Ruckova
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, 656 53 Brno, Czech Republic
| | - Petr Muller
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, 656 53 Brno, Czech Republic
| | - Borek Vojtesek
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, 656 53 Brno, Czech Republic
| | - Robin Fahraeus
- INSERM Unité 940, Institut de Génétique Moléculaire, Université Paris 7, Hôpital St Louis, 27 rue Juliette Dodu, Paris, France
| | - David Argyle
- University of Edinburgh, Institute of Genetic and Molecular Medicine and School of Veterinary Medicine, Edinburgh, EH4 2XR, United Kingdom
| | - Ted R. Hupp
- University of Edinburgh, Institute of Genetic and Molecular Medicine and School of Veterinary Medicine, Edinburgh, EH4 2XR, United Kingdom
- * E-mail:
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3
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Green JM. Glucarpidase to combat toxic levels of methotrexate in patients. Ther Clin Risk Manag 2012; 8:403-13. [PMID: 23209370 PMCID: PMC3511185 DOI: 10.2147/tcrm.s30135] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Indexed: 12/05/2022] Open
Abstract
In January 2012, glucarpidase (Voraxaze®) received approval from the US Food and Drug Administration for intravenous treatment of toxic plasma methotrexate concentrations due to impaired renal clearance. Methotrexate, an antifolate agent, has been used for over 60 years in the treatment of various cancers. High-dose methotrexate has been particularly useful in the treatment of leukemias and lymphomas. However, even with aggressive hydration and urine alkalinization, such regimens can lead to acute renal dysfunction, as indicated by decreases in urine production and concomitant increases in blood urea nitrogen and serum creatinine levels. Because methotrexate is largely excreted by the kidneys, this can greatly potentiate tissue damage. Toxic levels of blood methotrexate can be rapidly and effectively decreased by intravenous administration of glucarpidase. Glucarpidase is a recombinant form of carboxypeptidase G2, a bacterial enzyme that rapidly cleaves methotrexate to form the amino acid glutamate and 2,4-diamino-N10-methylpteroic acid. Catabolites of methotrexate are much less toxic than the parent compound, and are primarily excreted by hepatic mechanisms. Glucarpidase has been available on a compassionate basis since the 1990s, and a variety of case reports and larger clinical trials have demonstrated the safety and efficacy of this drug in patients ranging in age from infants to the elderly and in a variety of races and ethnic groups. Glucarpidase should not be administered within 2 hours of leucovorin, because this agent is a reduced folate which competes with methotrexate for the enzyme and glucarpidase inactivates leucovorin. Side effects of glucarpidase are rare and relatively mild, and include paraesthesia, flushing, nausea, vomiting, pruritus, and headache. Glucarpidase has seen limited use in intrathecal treatment of methotrexate toxicity for which it is also effective. Future applications of this enzyme in chemotherapy continue to be an active area of research.
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Yang Q, Larsen SK, Mi Z, Robbins PD, Basse PH. PTD-mediated loading of tumor-seeking lymphocytes with prodrug-activating enzymes. AAPS JOURNAL 2008; 10:614-21. [PMID: 19104945 DOI: 10.1208/s12248-008-9066-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 11/10/2008] [Indexed: 12/21/2022]
Abstract
Using the approach of peptide transduction domain (PTD)-mediated loading of interleukin-2(IL-2)-activated natural killer (A-NK) cells, tumor-seeking lymphocytes, with prodrug-activating enzymes, we primarily aim to generate a cytotoxic drug selectively within tumors and minimize damage to normal tissues. A-NK cells are able to accumulate selectively at tumor sites. While these cells by themselves possess significant antitumor effect in vivo, we suggest that they can also serve as Trojan horses, by bringing anticancer agents, such as prodrug-activating enzymes, selectively to tumors. We have successfully demonstrated in a mouse model that A-NK cells can be rapidly loaded with prodrug-activating enzymes, such as alkaline phosphatase (AP) and beta-galactosidase (beta-gal), in vitro using enzyme-conjugated peptide PTD5. Upon adoptive transfer into lung-tumor-bearing animals, the loaded A-NK cells are able to bring their cargo of the prodrug-activating enzymes selectively to pulmonary metastases. The targeting of the AP to the tumor tissues is highly specific, since more than a fivefold higher concentration of AP was found in the tumor tissues compared to the surrounding normal lung tissue at 24 h after injection. The approach of transporting prodrug-activating enzymes selectively into tumors clearly shows potential for future targeted chemotherapy. Ongoing studies in our laboratory are evaluating the antitumor efficacy of cellular-dependent enzyme prodrug therapy.
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Affiliation(s)
- Qin Yang
- Department of Immunology, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, University of Pittsburgh, 5150 Center Avenue, Suite 1A-106, Pittsburgh, Pennsylvania. 15232, USA.
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5
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Pedone E, Searle F, Brocchini S. Diethylstilbestrol glutamate as a potential substrate for ADEPT. J Drug Target 2008; 14:437-43. [PMID: 17092843 DOI: 10.1080/10611860600834573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The combination of systemic toxicity, water insolubility and a labile chemical structure has limited the clinical use of diethylstilbestrol (DES) 1 for the treatment of prostate cancer. To determine if DES could potentially be a prodrug substrate for the pre-targeting strategy known as antibody directed enzyme prodrug therapy (ADEPT), the DES-glutamate 5 was prepared. The synthesis required the activation of the bis-t-butyl glutamate ester 2 to the isocyanate 3 followed by addition of DES 1. The desired DES-glutamate 5 was water-soluble and upon incubation with carboxypeptidase G2 (CPG2) underwent carbamate cleavage to give DES 1. A control reaction in the absence of CPG2 demonstrated that the enzyme was necessary for rapid glutamate cleavage to give DES 1. HPLC analysis was required to follow the reaction of DES-glutamate 5 with CPG2. These preliminary results suggest that it may be possible to examine an ADEPT strategy for DES provided enzymatic kinetics can be measured.
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Affiliation(s)
- Elisa Pedone
- Department of Pharmaceutics, The School of Pharmacy, University of London, 29-39, Brunswick Square, London WC1N 1AX, UK
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6
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Abstract
Antibody-directed enzyme prodrug therapy was conceived as a means of restricting the action of cytotoxic drugs to tumor sites. Since antigenic targets were a central component of the approach, colonic cancer, with its virtually universal expression of carcinoembryonic antigen at the cellular level, presented an obvious starting point. The principle of antibody-directed enzyme prodrug therapy is to use an antibody directed at a tumor-associated antigen to vector an enzyme to tumor sites. The enzyme should be retained at tumor sites after it has cleared from blood and normal tissues. A nontoxic prodrug, a substrate for the enzyme, is then given and, by cleaving an inactivating component from the prodrug, a potent cytotoxic agent is generated. One of the potential advantages of such a system is that a small cytotoxic agent, generated within a tumor site, is much more diffusible than a large antibody molecule. Moreover, failure to express the target antigen by cancer cells does not protect them from the bystander action of the cytotoxic agent. This review will primarily consider the studies of the London group since this is the only group that has so far reported clinical trials and it is only through clinical trials that the requirements of a successful antibody-directed enzyme prodrug therapy system can be identified.
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Affiliation(s)
- Kenneth D Bagshawe
- Imperial College London, Department of Medical Oncology, Charing Cross Campus, Fulham Palace Road, London W6 8RF, UK.
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7
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Graham-Cole CL, Thomas HD, Taylor GA, Newell DR, Melton RG, Hesp R, Boddy AV. An evaluation of thymidine phosphorylase as a means of preventing thymidine rescue from the thymidylate synthase inhibitor raltitrexed. Cancer Chemother Pharmacol 2006; 59:197-206. [PMID: 16721548 DOI: 10.1007/s00280-006-0258-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Accepted: 04/23/2006] [Indexed: 10/24/2022]
Abstract
The antitumour effect of thymidylate synthase inhibitors such as raltitrexed (RTX) may be reversed by salvage of thymidine (Thd). Since thymidine phosphorylase (TP) depletes Thd, the potential for tumour-selective depletion of Thd using antibody-mediated delivery of TP to tumours was investigated. In vitro studies demonstrated that 25 x 10(-3) units/ml TP depleted extracellular Thd (3 microM) and restored sensitivity to the growth inhibitory effects of RTX in Lovo and HT29 cell lines. Thymidine concentrations in xenograft tumours were inversely proportional to the activity of TP in the tumour, and the presence of a subcutaneous Lovo xenograft reduced plasma Thd concentrations from 0.92 +/- 0.07 to 0.37 +/- 0.04 microM. Intravenous administration of native TP enzyme depleted plasma Thd to 5 nM, but following rapid elimination of TP, plasma Thd returned to pretreatment values. There was no effect on tumour TP or Thd. Conjugation of TP to the A5B7 F(ab)2 antibody fragment, which targets carcinoembryonic antigen (CEA) expressed on colorectal cell-lines such as Lovo, did result in selective accumulation of TP in the tumour. However, there was no tumour-selective depletion of Thd and there did not appear to be any potential benefit of combining antibody-targeted TP with RTX.
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Affiliation(s)
- Claire L Graham-Cole
- Northern Institute for Cancer Research, Medical School, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK
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8
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Bagshawe KD, Sharma SK, Begent RHJ. Antibody-directed enzyme prodrug therapy (ADEPT) for cancer. Expert Opin Biol Ther 2005; 4:1777-89. [PMID: 15500406 DOI: 10.1517/14712598.4.11.1777] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Antibody-directed enzyme prodrug therapy (ADEPT) aims to restrict the cytotoxic action to tumour sites. The obstacles to achieve this were recognised at the outset, but time and experience have given these better definition. The development of fusion proteins has provided the means of making consistent antibody-enzyme constructs on an adequate scale, and glycosylation has provided the means to control the clearance of enzyme from non-tumour sites. Human enzymes have yet to be tested in a clinical setting, and there are pointers indicating that the immunological response to foreign enzymes can be overcome. The relatively small number of purpose-designed prodrugs tested so far leaves this an area ripe for further development. The ongoing iterative process between preclinical and clinical studies is critical to achieving the objective.
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Affiliation(s)
- Kenneth D Bagshawe
- Department of Oncology, Royal Free & University College Medical School, University College London, UK
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9
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Bagshawe KD, Burke PJ, Knox RJ, Melton RG, Sharma SK. Targeting enzymes to cancers - new developments. Expert Opin Investig Drugs 2005; 8:161-72. [PMID: 15992070 DOI: 10.1517/13543784.8.2.161] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Two methods of using tumour located enzymes have been described. These are antibody directed enzyme prodrug therapy (ADEPT) and macromolecule directed enzyme prodrug therapy (MDEPT), where the tumour located enzyme converts a non-toxic prodrug into a cytotoxic drug at tumour sites. The alternative use of tumour located enzymes is to inactivate rescue agents that protect cells from antimetabolite action, and is described as 'Antimetabolite with inactivation of rescue agent at cancer sites' (AMIRACS). The leakiness of tumour blood vessels and poor lymphatic drainage allows enzymes to be targeted to many cancers by attachment to polymeric macromolecules (MDEPT), as well as to antibodies and antibody fragments (ADEPT). To avoid systemic toxicity, enzyme activity in blood and normal tissues must be very low before giving a prodrug or rescue agent. Antibodies directed against the enzyme component of macromolecular conjugates have proved to be very efficient at clearing normal tissues. Human enzymes which are over expressed by cancer cells can be exploited particularly if they require co-factors or co-substrates, either in situ or targeted to extracellular sites. Bacterial enzymes have advantages in specificity but require some form of immunological control in view of their immunogenicity. Prodrugs which generate drugs with very short half lives are desirable, and have been developed, including one which has a differential toxicity between prodrug and the active drug of 1000 to 10,000 fold. The range of antimetabolites available for AMIRACS was initially restricted to inhibitors of dihydrofolate reductase but has been greatly extended by the introduction of inhibitors of other enzymes. The limitations of these systems are discussed.
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Affiliation(s)
- K D Bagshawe
- Enzacta Ltd, Building 115, Porton Science Park, Salisbury, Wiltshire, SP4 0JQ, UK
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10
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Senter PD, Springer CJ. Selective activation of anticancer prodrugs by monoclonal antibody-enzyme conjugates. Adv Drug Deliv Rev 2001; 53:247-64. [PMID: 11744170 DOI: 10.1016/s0169-409x(01)00206-x] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A great deal of interest has surrounded the activities of monoclonal antibodies (mAbs), and mAb-drug, toxin and radionuclide conjugates for the treatment of human cancers. In the last few years, a number of new mAb-based reagents have been clinically approved (Rituxan, Herceptin, and Panorex), and several others are now in advanced clinical trials. Successful therapeutic treatment of solid tumors with drug conjugates of such macromolecules must overcome the barriers to penetration within tumor masses, antigen heterogeneity, conjugated drug potency, and efficient drug release from the mAbs inside tumor cells. An alternative strategy for drug delivery involves a two-step approach to cancer therapy in which mAbs are used to localize enzymes to tumor cell surface antigens. Once the conjugate binds to the cancer cells and clears from the systemic circulation, antitumor prodrugs are administered that are catalytically converted to active drugs by the targeted enzyme. The drugs thus released are capable of penetrating within the tumor mass and eliminating both cells that have and have not bound the mAb-enzyme conjugate. Significant therapeutic effects have been obtained using a broad range of enzymes along with prodrugs that are derived from both approved anticancer drugs and highly potent experimental agents. This review focuses on the activities of several mAb-enzyme/prodrug combinations, with an emphasis on those that have provided mechanistic insight, clinical activity, novel protein constructs, and the potential for reduced immunogenicity.
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Affiliation(s)
- P D Senter
- Seattle Genetics, 21823 30th Dr. SE, Bothell, WA 98021, USA.
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11
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Bagshawe KD, Sharma SK, Burke PJ, Melton RG, Knox RJ. Developments with targeted enzymes in cancer therapy. Curr Opin Immunol 1999; 11:579-83. [PMID: 10508703 DOI: 10.1016/s0952-7915(99)00004-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cancer therapy based on the delivery of enzymes to tumour sites has advanced in several directions since antibody-directed enzyme/prodrug therapy was first described. It has been shown that methoxypolyethylene glycol (MPEG) can be used to deliver enzyme to a variety of solid tumours. MPEG-enzyme conjugates show reduced immunogenicity and may allow repeated treatment with enzymes of bacterial origin. Enzyme delivery to tumours by polymers can be used to convert a low toxicity prodrug to a potent cytotoxic agent. An example of such a prodrug is CB1954, which can be activated by a human enzyme in the presence of a cosubstrate. Tumour-located enzymes can also be used in conjunction with a combination of antimetabolites and rescue agents. The rescue agent protects normal tissue but is degraded at cancer sites by the enzyme, thus deprotecting the tumour and allowing prolonged antimetabolite action.
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Affiliation(s)
- K D Bagshawe
- Department of Medical Oncology, Imperial College of Medicine, Charing Cross campus London, W6 8RP, UK.
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12
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Khan TH, Eno-Amooquaye EA, Searle F, Browne PJ, Osborn HM, Burke PJ. Novel inhibitors of carboxypeptidase G2 (CPG2): potential use in antibody-directed enzyme prodrug therapy. J Med Chem 1999; 42:951-6. [PMID: 10090777 DOI: 10.1021/jm990004i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The design and synthesis of potent thiocarbamate inhibitors for carboxypeptidase G2 are described. The best thiocarbamate inhibitor N-(p-methoxybenzenethiocarbonyl)amino-L-glutamic acid 6d, chosen for preliminary investigations of in vitro antibody-directed enzyme prodrug therapy (ADEPT), abrogated the cytotoxicity of a combination of A5B7-carboxypeptidase G2 conjugate and prodrug PGP (N-p-{N,N-bis (2-chloroethyl)amino}phenoxycarbonyl-L-glutamate) toward LS174T cells. This is the first report of a small-molecule enzyme inhibitor proposed for use in conjunction with the ADEPT approach.
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Affiliation(s)
- T H Khan
- Imperial College of Science, Technology and Medicine, Charing Cross Site, Medical Oncology, St. Dunstan's Road, London W6 8RF, UK
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13
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Tilby MJ, McCartney H, Gould KA, O'Hare CC, Hartley JA, Hall AG, Golding BT, Lawley PD. A monofunctional derivative of melphalan: preparation, DNA alkylation products, and determination of the specificity of monoclonal antibodies that recognize melphalan-DNA adducts. Chem Res Toxicol 1998; 11:1162-8. [PMID: 9778312 DOI: 10.1021/tx980129a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bifunctional alkylating agents, such as those based on nitrogen mustard, form important parts of many anti-cancer chemotherapy protocols and are responsible for increased incidences of secondary tumors in successfully treated patients. These drugs generally form a majority of monofunctional DNA adducts, although the bifunctional adducts appear to be necessary for their powerful cytotoxic and antitumor effects. The relative importance of bifunctional as opposed to monofunctional adducts in the varied biological consequences of drug exposure has not been studied in detail, particularly in relation to the role and specificity of biochemical responses to therapy-related DNA damage. A simple method is described for the preparation of useful quantities of a pure monofunctional derivative of the nitrogen mustard-based drug melphalan. Monohydroxymelphalan was prepared by partial hydrolysis, purified by reversed phase chromatography, and characterized by MS, NMR, and HPLC. Contamination with melphalan was </=0.2%. The heat labile DNA base adducts formed by monohydroxymelphalan were shown to contain undetectable levels of cross-linked species. The ratio of adenine to guanine adducts was 0.62, similar to the equivalent ratio for melphalan. The sequence-dependent pattern of alkylation of purified DNA was indistinguishable from that of melphalan, but required a higher dose to achieve comparable extents of reaction. The specificities of two monoclonal antibodies that recognize melphalan-DNA adducts were investigated using DNA alkylated with [3H]monohydroxymelphalan. Adducts on this DNA showed similar immunoreactivities to adducts formed by melphalan. This shows clearly that neither antibody was specific for cross-linked adducts and that it is therefore possible to quantify adducts formed by both monohydroxymelphalan and melphalan with high sensitivities. The availability of monohydroxymelphalan in addition to melphalan, together with sensitive immunoassays for adducts on extracted DNA and in individual cells, constitutes a useful system for investigating cellular responses to the DNA modifications formed by a clinically relevant drug.
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Affiliation(s)
- M J Tilby
- Leukaemia Research Fund Laboratory and Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne NE2 4HH, U.K.
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14
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Denny WA, Wilson WR. The design of selectively-activated anti-cancer prodrugs for use in antibody-directed and gene-directed enzyme-prodrug therapies. J Pharm Pharmacol 1998; 50:387-94. [PMID: 9625483 DOI: 10.1111/j.2042-7158.1998.tb06878.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Systemic anti-proliferative agents (cytotoxins) have been the most successful single design concept for anti-cancer drugs. However, they have inherent limitations (they target dividing cells rather than cancer cells) which limit their clinical efficacy, especially toward the more slowly-growing solid tumours. New concepts are required to improve the selectivity of their killing of tumour cells. One possibility is the use of prodrugs which can be activated selectively in tumour tissue. Several potential mechanisms for this are being explored, including tumour hypoxia, low extracellular pH, therapeutic radiation and tumour-specific endogenous or exogenous enzymes. In the last approach the exogenous enzyme can be delivered by attachment to monoclonal antibodies (ADEPT) or as DNA constructs containing the corresponding gene (GDEPT). A limitation of both approaches is that only a small proportion of the tumour cells become activation-competent, but this can be substantially overcome by the design of appropriate prodrugs capable of killing activation-incompetent cells via a bystander effect. We have proposed a modular approach to prodrug design in which a trigger unit determines tumour selectivity and an effector unit achieves the desired level of killing of cells when the trigger is activated. For ADEPT and GDEPT prodrugs the primary requirement of the trigger is efficient and selective activation by the appropriate enzyme; the released effector must be a potent, diffusible cytotoxin which fully exploits the small proportion of cells capable of activating the prodrug. A wide variety of chemistries has been used, but many of the existing effectors do not have all of these properties. We report work on two types of cytotoxin derived from very potent anti-tumour antibiotics (enediynes and amino-seco-cyclopropylindolines) as effectors in prodrugs for ADEPT and GDEPT applications.
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Affiliation(s)
- W A Denny
- Cancer Society Research Laboratory, Faculty of Medicine and Health Science, The University of Auckland, New Zealand
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Abstract
Antibody-directed enzyme prodrug therapy (ADEPT) is a therapeutic strategy which aims to improve the selectivity of anticancer drugs. ADEPT is a two-step antibody targeting system that has benefits over a one-step chemo-, toxin- or radioimmunoconjugate. The basic principles of ADEPT are discussed alongside the requirements of the components: antibodies, enzymes and prodrugs. The design and syntheses of prodrugs are detailed particularly prodrug/drug systems of potential clinical use, the rationale behind their design and the in vitro and in vivo results obtained. The main features of ADEPT, such as targeting of cancer cells by the antibody-enzyme conjugates, enzymic activation of the prodrugs, selection of the prodrug/drug and enzyme/prodrug systems are reviewed.
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Schmidt F, Florent J, Monneret C, Straub R, Czech J, Gerken M, Bosslet K. Glucuronide prodrugs of hydroxy compounds for antibody directed enzyme prodrug therapy (ADEPT) : A phenol nitrogen mustard carbamate. Bioorg Med Chem Lett 1997. [DOI: 10.1016/s0960-894x(97)00157-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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