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Plant Ribosome-Inactivating Proteins: Progesses, Challenges and Biotechnological Applications (and a Few Digressions). Toxins (Basel) 2017; 9:toxins9100314. [PMID: 29023422 PMCID: PMC5666361 DOI: 10.3390/toxins9100314] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/29/2017] [Accepted: 10/03/2017] [Indexed: 12/11/2022] Open
Abstract
Plant ribosome-inactivating protein (RIP) toxins are EC3.2.2.22 N-glycosidases, found among most plant species encoded as small gene families, distributed in several tissues being endowed with defensive functions against fungal or viral infections. The two main plant RIP classes include type I (monomeric) and type II (dimeric) as the prototype ricin holotoxin from Ricinus communis that is composed of a catalytic active A chain linked via a disulphide bridge to a B-lectin domain that mediates efficient endocytosis in eukaryotic cells. Plant RIPs can recognize a universally conserved stem-loop, known as the α-sarcin/ ricin loop or SRL structure in 23S/25S/28S rRNA. By depurinating a single adenine (A4324 in 28S rat rRNA), they can irreversibly arrest protein translation and trigger cell death in the intoxicated mammalian cell. Besides their useful application as potential weapons against infected/tumor cells, ricin was also used in bio-terroristic attacks and, as such, constitutes a major concern. In this review, we aim to summarize past studies and more recent progresses made studying plant RIPs and discuss successful approaches that might help overcoming some of the bottlenecks encountered during the development of their biomedical applications.
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2
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Simon N, FitzGerald D. Immunotoxin Therapies for the Treatment of Epidermal Growth Factor Receptor-Dependent Cancers. Toxins (Basel) 2016; 8:toxins8050137. [PMID: 27153091 PMCID: PMC4885052 DOI: 10.3390/toxins8050137] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 04/20/2016] [Accepted: 04/22/2016] [Indexed: 12/17/2022] Open
Abstract
Many epithelial cancers rely on enhanced expression of the epidermal growth factor receptor (EGFR) to drive proliferation and survival pathways. Development of therapeutics to target EGFR signaling has been of high importance, and multiple examples have been approved for human use. However, many of the current small molecule or antibody-based therapeutics are of limited effectiveness due to the inevitable development of resistance and toxicity to normal tissues. Recombinant immunotoxins are therapeutic molecules consisting of an antibody or receptor ligand joined to a protein cytotoxin, combining the specific targeting of a cancer-expressed receptor with the potent cell killing of cytotoxic enzymes. Over the decades, many bacterial- or plant-based immunotoxins have been developed with the goal of targeting the broad range of cancers reliant upon EGFR overexpression. Many examples demonstrate excellent anti-cancer properties in preclinical development, and several EGFR-targeted immunotoxins have progressed to human trials. This review summarizes much of the past and current work in the development of immunotoxins for targeting EGFR-driven cancers.
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Affiliation(s)
- Nathan Simon
- Biotherapy Section, Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, 37/5124 Bethesda, MD 20892, USA.
| | - David FitzGerald
- Biotherapy Section, Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, 37/5124 Bethesda, MD 20892, USA.
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Lian C, Ruan L, Shang D, Wu Y, Lu Y, Lü P, Yang Y, Wei Y, Dong X, Ren D, Chen K, Liu H, Tu Z. Heparin-Binding Epidermal Growth Factor-Like Growth Factor as a Potent Target for Breast Cancer Therapy. Cancer Biother Radiopharm 2016; 31:85-90. [DOI: 10.1089/cbr.2015.1956] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Caixia Lian
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Lingling Ruan
- School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Dongsheng Shang
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Yanfang Wu
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Yongjin Lu
- School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Peng Lü
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Yuhua Yang
- School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Yajun Wei
- School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Xiaojing Dong
- School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Dewan Ren
- School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Keping Chen
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
| | - Hanqing Liu
- School of Pharmacy, Jiangsu University, Zhenjiang, China
| | - Zhigang Tu
- Institute of Life Sciences, Jiangsu University, Zhenjiang, China
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Wei LQ, Liang HT, Qin DC, Jin HF, Zhao Y, She MC. MiR-212 exerts suppressive effect on SKOV3 ovarian cancer cells through targeting HBEGF. Tumour Biol 2014; 35:12427-34. [PMID: 25201063 DOI: 10.1007/s13277-014-2560-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 08/26/2014] [Indexed: 01/27/2023] Open
Abstract
MicroRNAs (miRNAs) play critical roles in the development and progression of ovarian cancer. We found that miR-212 was significantly downregulated in serum and tissues from epithelial ovarian cancer (EOC) patients. Overexpression of miR-212 in ovarian cancer cells inhibited cell proliferation, migration, and invasion. Luciferase reporter assay confirmed HBEGF as a direct target of miR-212. Overexpression of miR-212 decreased HBEGF expression at both the protein and messenger RNA (mRNA) levels. Knockdown of HBEGF expression in SKOV3 cell line significantly inhibited cell growth, migration, and invasion. HBEGF mRNA level was upregulated in EOC tissues and inversely correlated with miR-212 expression in tissues. Upregulation of HBEGF could attenuate the effect induced by miR-212. These findings indicate that miR-212 displays a tumor-suppressive effect in human ovarian cancer. And miR-212 suppresses cell proliferation, migration, and invasion by targeting the HBEGF transcript, highlighting the therapeutic potential of miR-212 and HBEGF in epithelial ovarian cancer treatment.
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Affiliation(s)
- Li-Qiang Wei
- Department of Clinical Laboratory, The First Affiliated Hospital of Zhengzhou University, No. 1, Jianshe Road, Zhengzhou, 450052, Henan, China
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5
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Tamburino R, Pizzo E, Sarcinelli C, Poerio E, Tedeschi F, Ficca AG, Parente A, Di Maro A. Enhanced cytotoxic activity of a bifunctional chimeric protein containing a type 1 ribosome-inactivating protein and a serine protease inhibitor. Biochimie 2012; 94:1990-6. [PMID: 22659569 DOI: 10.1016/j.biochi.2012.05.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 05/22/2012] [Indexed: 11/29/2022]
Abstract
Both ribosome-inactivating proteins (RIPs) and plant proteinase inhibitors, belong to protein families known to regulate cellular homeostasis and likely involved in plant defense. Nevertheless the interest in these protein classes is due to their potential use for the treatment of several important human diseases such as cancer. Thus, in the present study, type 1 ribosome-inactivating protein and wheat subtilisin/chymotrypsin inhibitor, were engineered into a chimeric protein with cytotoxic action selective for murine tumor cells, while lacking any appreciable toxicity on murine normal cells. This chimeric protein selectively sensitizes to apoptotic death cells derived from Simian-virus-40-transformed mouse fibroblasts (SVT2 cells). The cytotoxicity of this new recombinant product has been detected also on three different human malignant cells. Therefore action on tumor cells of this protein could represent a potentially very attractive novel tool for anticancer drug design.
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Affiliation(s)
- Rachele Tamburino
- Dipartimento di Scienze della Vita, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta, Italy
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A class of human proteins that deliver functional proteins into mammalian cells in vitro and in vivo. ACTA ACUST UNITED AC 2011; 18:833-8. [PMID: 21802004 DOI: 10.1016/j.chembiol.2011.07.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 07/01/2011] [Accepted: 07/07/2011] [Indexed: 01/16/2023]
Abstract
We discovered a class of naturally occurring human proteins with unusually high net positive charge that can potently deliver proteins in functional form into mammalian cells both in vitro and also in murine retina, pancreas, and white adipose tissues in vivo. These findings represent diverse macromolecule delivery agents for in vivo applications, and also raise the possibility that some of these human proteins may penetrate cells as part of their native biological functions.
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7
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Egan K, Crowley D, Smyth P, O'Toole S, Spillane C, Martin C, Gallagher M, Canney A, Norris L, Conlon N, McEvoy L, Ffrench B, Stordal B, Keegan H, Finn S, McEneaney V, Laios A, Ducrée J, Dunne E, Smith L, Berndt M, Sheils O, Kenny D, O'Leary J. Platelet adhesion and degranulation induce pro-survival and pro-angiogenic signalling in ovarian cancer cells. PLoS One 2011; 6:e26125. [PMID: 22022533 PMCID: PMC3192146 DOI: 10.1371/journal.pone.0026125] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 09/20/2011] [Indexed: 01/22/2023] Open
Abstract
Thrombosis is common in ovarian cancer. However, the interaction of platelets with ovarian cancer cells has not been critically examined. To address this, we investigated platelet interactions in a range of ovarian cancer cell lines with different metastatic potentials [HIO-80, 59M, SK-OV-3, A2780, A2780cis]. Platelets adhered to ovarian cancer cells with the most significant adhesion to the 59M cell line. Ovarian cancer cells induced platelet activation [P-selectin expression] in a dose dependent manner, with the most significant activation seen in response to the 59M cell line. The platelet antagonists [cangrelor, MRS2179, and apyrase] inhibited 59M cell induced activation suggesting a P2Y12 and P2Y1 receptor mediated mechanism of platelet activation dependent on the release of ADP by 59M cells. A2780 and 59M cells potentiated PAR-1, PAR-4, and TxA2 receptor mediated platelet activation, but had no effect on ADP, epinephrine, or collagen induced activation. Analysis of gene expression changes in ovarian cancer cells following treatment with washed platelets or platelet releasate showed a subtle but valid upregulation of anti-apoptotic, anti-autophagy pro-angiogenic, pro-cell cycle and metabolic genes. Thus, ovarian cancer cells with different metastatic potential adhere and activate platelets differentially while both platelets and platelet releasate mediate pro-survival and pro-angiogenic signals in ovarian cancer cells.
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Affiliation(s)
- Karl Egan
- Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Darragh Crowley
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Paul Smyth
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Sharon O'Toole
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
- Department of Obstetrics and Gynaecology, Trinity College Dublin, Dublin, Ireland
| | - Cathy Spillane
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Cara Martin
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Michael Gallagher
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Aoife Canney
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Lucy Norris
- Department of Obstetrics and Gynaecology, Trinity College Dublin, Dublin, Ireland
| | - Niamh Conlon
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Lynda McEvoy
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Brendan Ffrench
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Britta Stordal
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Helen Keegan
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Stephen Finn
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | | | - Alex Laios
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
- Department of Obstetrics and Gynaecology, Trinity College Dublin, Dublin, Ireland
| | - Jens Ducrée
- The Biomedical Diagnostics Institute, Dublin City University, Dublin, Ireland
| | - Eimear Dunne
- Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Leila Smith
- Fluidigm Corporation [Europe], Amsterdam, Netherlands
| | - Michael Berndt
- Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland
- The Biomedical Diagnostics Institute, Dublin City University, Dublin, Ireland
| | - Orla Sheils
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
| | - Dermot Kenny
- Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland
- The Biomedical Diagnostics Institute, Dublin City University, Dublin, Ireland
| | - John O'Leary
- Department of Histopathology, Trinity College Dublin, Dublin, Ireland
- * E-mail:
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8
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Selective formation of covalent protein heterodimers with an unnatural amino acid. ACTA ACUST UNITED AC 2011; 18:299-303. [PMID: 21439474 DOI: 10.1016/j.chembiol.2011.01.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 01/07/2011] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
We report a strategy for the generation of heterodimeric protein conjugates using an unnatural amino acid with orthogonal reactivity. This paper addresses the challenges of site-specificity and homogeneity with respect to the synthesis of bivalent proteins and antibody-drug conjugates. There are numerous antibody-drug conjugates in preclinical and clinical development, yet these are based either on nonspecific lysine coupling chemistry or on disulfide modification made difficult by the large number of cysteines in antibodies. Here, we describe a recombinant approach that can be used to rapidly generate a variety of constructs with defined conjugation sites. Moreover, this methodology results in homogeneous antibody conjugates whose biological, physical, and pharmacological properties can be quantitatively assessed and subsequently optimized. As proof of concept, we have generated anti-Her2 Fab-Saporin conjugates that demonstrate excellent potency in vitro.
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9
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Nautiyal J, Kanwar SS, Majumdar APN. EGFR(s) in aging and carcinogenesis of the gastrointestinal tract. Curr Protein Pept Sci 2011; 11:436-50. [PMID: 20491625 DOI: 10.2174/138920310791824110] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 05/20/2010] [Indexed: 12/24/2022]
Abstract
Cells of the gastrointestinal (GI) mucosa are subject to a constant process of renewal which, in normal adults, reflects a balance between the rates of cell production and cell loss. Detailed knowledge of these events is, therefore, essential for a better understanding of the normal aging processes as well as many GI diseases, particularly malignancy, that represent disorders of tissue growth. In general, many GI dysfunctions, including malignancy, increase with advancing age, and aging itself is associated with alterations in structural and functional integrity of the GI tract. Although the regulatory mechanisms for age-related increase in the incidence of GI-cancers are yet to be fully delineated, recent evidence suggests a role for epidermal growth family receptors and its family members {referred to as EGFR(s)} in the development and progression of carcinogenesis during aging. The present communication discusses the involvement of EGFR(s) in regulating events of GI cancers during advancing age and summarizes the current available therapeutics targeting these receptors. The current review also describes the effectiveness of ErbB inhibitors as well as combination therapies. Additionally, the involvement of GI stem cells in the development of the age-related rise in GI cancers is emphasized.
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Affiliation(s)
- Jyoti Nautiyal
- Veterans Affairs Medical Center, Wayne State University, Detroit, MI 48201, USA
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10
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de Virgilio M, Lombardi A, Caliandro R, Fabbrini MS. Ribosome-inactivating proteins: from plant defense to tumor attack. Toxins (Basel) 2010; 2:2699-737. [PMID: 22069572 PMCID: PMC3153179 DOI: 10.3390/toxins2112699] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 10/29/2010] [Accepted: 11/04/2010] [Indexed: 12/02/2022] Open
Abstract
Ribosome-inactivating proteins (RIPs) are EC3.2.32.22 N-glycosidases that recognize a universally conserved stem-loop structure in 23S/25S/28S rRNA, depurinating a single adenine (A4324 in rat) and irreversibly blocking protein translation, leading finally to cell death of intoxicated mammalian cells. Ricin, the plant RIP prototype that comprises a catalytic A subunit linked to a galactose-binding lectin B subunit to allow cell surface binding and toxin entry in most mammalian cells, shows a potency in the picomolar range. The most promising way to exploit plant RIPs as weapons against cancer cells is either by designing molecules in which the toxic domains are linked to selective tumor targeting domains or directly delivered as suicide genes for cancer gene therapy. Here, we will provide a comprehensive picture of plant RIPs and discuss successful designs and features of chimeric molecules having therapeutic potential.
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Affiliation(s)
| | - Alessio Lombardi
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Milan, Italy;
| | - Rocco Caliandro
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Bari, Italy;
| | - Maria Serena Fabbrini
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Milan, Italy;
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11
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Lu P, Feng MG. Bifunctional enhancement of a β-glucanase-xylanase fusion enzyme by optimization of peptide linkers. Appl Microbiol Biotechnol 2008; 79:579-87. [PMID: 18415095 DOI: 10.1007/s00253-008-1468-4] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 03/20/2008] [Accepted: 03/23/2008] [Indexed: 11/29/2022]
Affiliation(s)
- Ping Lu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
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12
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Weyergang A, Selbo PK, Berg K. Photochemically stimulated drug delivery increases the cytotoxicity and specificity of EGF-saporin. J Control Release 2006; 111:165-73. [PMID: 16466823 DOI: 10.1016/j.jconrel.2005.12.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 11/25/2005] [Accepted: 12/01/2005] [Indexed: 11/25/2022]
Abstract
Epidermal growth factor receptor (EGFR) targeting has become a major field in both cancer research and therapy. In the present study an EGF-saporin affinity toxin has been established and evaluated in two EGFR overexpressing cancer cell lines. The binding of saporin to EGF did not influence the ribosome-inactivating activity of saporin as measured by a luminescence based reticulocyte lysate assay. Control experiments, using untargeted saporin, EGFR-negative cell lines and competition with EGF and anti-EGFR antibody were used to document selective uptake of the affinity toxin. One limitation in administration of macromolecular-drugs is lysosomal degradation. Photochemical internalization (PCI) is a modality for cytosolic release of macromolecules based on photochemical rupture of endocytic membranes and subsequent drug release. It was shown that PCI increases the toxicity of EGF-saporin significantly in EGFR-positive cells. EGF binding to saporin enhanced the PCI-induced cytotoxicity in NuTu-19 cells about 1000-fold when the photochemical treatment alone killed 50% of the cells. In conclusion, PCI of EGF-saporin is a promising method for increasing the efficiency of protein toxin-based cancer therapies. PCI of targeting toxins also exert a triple tumour-selectivity; utilization of an affinity toxin, preferential accumulation of the photosensitizer in neoplastic lesions, and site-directed light activation.
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Affiliation(s)
- Anette Weyergang
- Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway.
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Hossann M, Li Z, Shi Y, Kreilinger U, Büttner J, Vogel PD, Yuan J, Wise JG, Trommer WE. Novel immunotoxin: a fusion protein consisting of gelonin and an acetylcholine receptor fragment as a potential immunotherapeutic agent for the treatment of Myasthenia gravis. Protein Expr Purif 2005; 46:73-84. [PMID: 16230023 DOI: 10.1016/j.pep.2005.08.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 08/15/2005] [Accepted: 08/17/2005] [Indexed: 11/22/2022]
Abstract
In continuation of our attempts for antigen-specific suppression of the immune system [I.L. Urbatsch, R.K.M. Sterz, K. Peper, W.E. Trommer, Eur. J. Immunol. 23(1993) 776-779] a novel fusion protein composed of amino acids 4-181 of the extracellular domain of the alpha-subunit of the human muscle acetylcholine receptor and the plant toxin gelonin was expressed in Escherichia coli. The fusion protein formed inclusion bodies but could be solubilized in the presence of guanidinium hydrochloride. After a simple two step purification and refolding procedure, it exhibited a native structure at least in the main immunogenic region as shown by antibodies recognizing a conformational epitope. Half maximal inhibition of translation was achieved at 46 ng/ml as compared to 4.6 ng/ml for native and 2.4 for recombinant gelonin. Its use as therapeutic agent for the treatment of Myasthenia gravis was investigated in an animal model. Female Lewis rats were immunized with complete acetylcholine receptor from the electric ray Torpedo californica and developed thereafter experimental autoimmune M. gravis. Quantitative assessment of the disease was achieved by repetitive stimulation of the Nervus tibialis. Rats showed no symptoms of M. gravis, neither visually nor electrophysiologically after treatment with the fusion protein as determined one and seven weeks after the second application. This approach may also be useful for the therapy of further autoimmune diseases by substituting other autoantigens for the AchR fragment in the fusion protein.
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Affiliation(s)
- Martin Hossann
- Department of Chemistry, TU Kaiserslautern, P.O. Box 3049, D-67653 Kaiserslautern, Germany
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Kim YH, Kim HS, Yoo JS. Effect of basic fibroblast growth factor-saporin (bFGF-SAP) conjugate on bovine choriocapillary endothelial cells. KOREAN JOURNAL OF OPHTHALMOLOGY 2005; 18:121-31. [PMID: 15635825 DOI: 10.3341/kjo.2004.18.2.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We evaluated the effect of a basic fibroblast growth factor (bFGF) and saporin conjugate (bFGF-SAP) on proliferation, migration and tubule formation in bovine choriocapillary endothelial cells (BCECs). Cell proliferation and MTS assays were done with 0.01, 0.1, 1, 10, and 100 nM bFGF-SAP, and an equimolar concentration of bFGF and saporin. TUNEL assay was performed to confirm apoptosis. Cells were treated with 1, 10, and 100 nM bFGF-SAP and migration assay and tubule formation assay were done. Results were evaluated with image analysis. All experiments were performed in triplicate and repeated three times. Viable cells (ID50 = 0.62) and cell proliferation by MTS assay (ID50 = 0.75 nM) were inhibited. Saporin caused cytotoxicity and inhibition of proliferation at high concentration. DNA fragmentation was identified by TUNEL assay. Migration and tubule formation were also inhibited. All mechanisms responsible for neovascularization were inhibited, and this could be applied in the management of subretinal choroidal neovascularization (SRN).
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Affiliation(s)
- Yeong Hoon Kim
- Department of Ophthalmology, St. Paul's Hospital, Catholic University Medical College, Seoul, Korea
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15
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Laskin JJ, Sandler AB. Epidermal growth factor receptor: a promising target in solid tumours. Cancer Treat Rev 2004; 30:1-17. [PMID: 14766123 DOI: 10.1016/j.ctrv.2003.10.002] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The epidermal growth factor receptor (EGFR) is expressed in a wide variety of solid tumours. It has been demonstrated that the EGFR-associated signaling pathway plays an important role in carcinogenesis and cancer progression. In the new therapeutic paradigm of molecular-targeted cancer therapy, interference with intracellular signaling cascades is an appealing treatment approach. Inhibitory strategies under study include monoclonal antibodies, tyrosine kinase inhibitors, EGFR-ligand conjugates, EGFR immunoconjugates, and antisense oligonucleotides. Many of these strategies have demonstrated efficacy against EGFR-expressing tumour cells in preclinical studies, prompting a large number of clinical trials. In particular, clinical studies using monoclonal antibody blockade and EGFR tyrosine kinase inhibitors have suggested that EGFR blockade is a well-tolerated and effective treatment strategy; however, more trials are needed to precisely define how these agents will fit into modern cancer care.
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Affiliation(s)
- Janessa J Laskin
- Division of Medical Oncology, British Columbia Cancer Agency, 600 West 10th Avenue, Vancouver, BC V5Z 4E6, Canada.
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16
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Sundberg AL, Blomquist E, Carlsson J, Steffen AC, Gedda L. Cellular retention of radioactivity and increased radiation dose. Model experiments with EGF-dextran. Nucl Med Biol 2003; 30:303-15. [PMID: 12745022 DOI: 10.1016/s0969-8051(02)00421-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Targeting of tumor cells with radiolabeled biomolecules is a possible approach to inactivate disseminated tumor cells. However, rapid degradation of the biomolecules after cellular internalization and subsequent excretion of the radioactivity is a problem. We studied the possibility of using dextran as a carrier of radionuclides to improve the intracellular retention. An EGF-dextran conjugate, aimed for targeting of tumor cells overexpressing the EGF-receptor, was used as model. Retention tests were performed with (125)I on different parts: [(125)I]-EGF-dextran-[(125)I], [(125)I]-EGF-dextran and EGF-dextran-[(125)I]. Comparisons were made with [(125)I]-EGF. The radiolabeled compounds were incubated with cultured glioma cells for different times. The cellular retention of radioactivity was then measured for up to 24 h. Expected radiation doses at the cellular level were calculated assuming that (131)I, instead of (125)I, was coupled to EGF and EGF-dextran. The results indicated that the EGF-part of the conjugate was degraded and the EGF-attached radioactivity was rapidly excreted, whereas radioactivity on dextran was retained intracellularly to a high degree, i.e. 70-80% of the radioactivity bound to dextran was still cell-associated after 24 h. The retention after 24 h was significantly higher (p < 0.001) when the radioactivity was on the dextran instead of the EGF-part. The radiolabeled EGF-dextran had a notably high specific radioactivity; up to 11 MBq/microg. There was potential for at least hundred times increased radiation dose per receptor interaction when the radioactivity was on the dextran part. The advantage with radioactivity on the dextran part was the high cellular retention and the high specific radioactivity (higher than previously reported for other residualizing labels) without severe loss of receptor specific binding. Thus, dextran seems suitable as a carrier of radionuclides aimed for therapy and gives potential for a highly increased radiation dose.
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Affiliation(s)
- Asa Liljegren Sundberg
- Division of Biomedical Radiation Sciences, Rudbeck Laboratory, Uppsala University, Sweden
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Heisler I, Keller J, Tauber R, Sutherland M, Fuchs H. A cleavable adapter to reduce nonspecific cytotoxicity of recombinant immunotoxins. Int J Cancer 2003; 103:277-82. [PMID: 12455044 DOI: 10.1002/ijc.10809] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
One of the problems associated with the administration of immunotoxins is hypersensitivity reaction such as vascular leak syndrome. This may be prevented by decreasing the plasma half-life. To improve immunotoxins with respect to reduced side effects, we have previously described the development of a cleavable adapter. This adapter links the toxic moiety and ligand that are usually directly coupled. In our study, the cytotoxicity of saporin linked either directly or via the adapter to epidermal growth factor (EGF) was evaluated in vitro. The immunotoxins exhibited similar cytotoxic activity towards A-431 and HER14 cells (IC(50) < 10 nM). The supernatant from 6 hr cultures of HER14 cells incubated in the presence of the adapter-containing immunotoxin exhibited a significantly reduced cytotoxicity as compared to the directly coupled immunotoxin. Western blotting revealed that the adapter was cleaved, thus supporting our proposal that cleavable adapters may reduce nonspecific effects. A similar reduced half-life was detected in platelet-poor plasma. In contrast MCF-7 cells remain unaffected by the immunotoxins. This was shown to be due to the absence of detectable EGF-receptor in comparison to A-431 and HER14 cells as determined by Western blotting. Furthermore, we could show that the adapter does not exert an effect on the N-glycosidase activity of saporin. These results suggest that the use of cleavable adapters may be a useful tool in immunotoxins for reducing the killing of surrounding noncancerous cells due to nonspecific binding.
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Affiliation(s)
- Iring Heisler
- Institut für Klinische Chemie und Pathobiochemie, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Berlin, Germany
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Noonberg SB, Benz CC. Tyrosine kinase inhibitors targeted to the epidermal growth factor receptor subfamily: role as anticancer agents. Drugs 2000; 59:753-67. [PMID: 10804033 DOI: 10.2165/00003495-200059040-00003] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Abnormal cell signal transduction arising from protein tyrosine kinases has been implicated in the initiation and progression of a variety of human cancers. Over the past 2 decades pharmaceutical and university laboratories have been involved in a tremendous effort to develop compounds that can selectively modulate these abnormal signalling pathways. Targeting receptor tyrosine kinases, especially the epidermal growth factor receptor subfamily, has been at the forefront of this effort as a result of strong clinical data correlating over-expression of these receptors with more aggressive cancers. There are a variety of strategies under development for inhibiting the kinase activity of these receptors, targeting both the extracellular and intracellular domains. Antibody-based approaches, immunotoxins and ligand-binding cytotoxic agents use the extracellular domain for targeted tumour therapy. Small molecule inhibitors target the intracellular catalytic region by interfering with ATP binding, while nonphosphorylatable peptides are aimed at the intracellular substrate binding region. Compounds that inhibit subsequent downstream signals from the receptor by interrupting intracellular protein recognition sequences are also being investigated. In the past 5 years enormous progress has been made in developing tyrosine kinase inhibitor compounds with sufficient potency, bioavailability and selectivity against this subfamily of receptor tyrosine kinases. The anti-HER2 monoclonal antibody, trastuzumab, for patients with metastatic breast cancer is the first of these inhibitor compounds to gain FDA approval. However, preclinical and clinical trials are ongoing with a variety of other monoclonal antibodies, immunotoxins, and small molecule quinazoline and pyrimidine-based inhibitors. Although their cytotoxic and cytostatic potential has been proven, they are not likely to replace standard chemotherapy regimens as single-agent, first-line therapeutics. Instead, their promising additive and synergistic antitumour effects in combination with standard chemotherapeutics suggest that these novel agents will find their greatest utility and efficacy in conjunction with existing anticancer agents.
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Affiliation(s)
- S B Noonberg
- University of California, San Francisco, Division of Hematology-Oncology, 94143, USA
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Ho JJ, Kim YS. Biliopancreatic malignancy: Future prospects for progress. Ann Oncol 1999. [DOI: 10.1093/annonc/10.suppl_4.s300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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