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Abstract
Recent advances in RNA engineering during the last two decades have supported the development of RNA-based therapeutics targeting a variety of human diseases. The broad scope of these emerging drugs clearly demonstrates the versatility of RNA. Ribozymes have been seen as promising candidates in this area. However, efficient intracellular application of ribozymes remains challenging, and other strategies appear to have outperformed ribozymes as molecular drugs. Nevertheless, trans-cleaving ribozymes have been applied for specific cleavage of target mRNAs in order to inhibit undesired gene expression. Furthermore, ribozymes have been engineered to allow site-directed RNA sequence alterations, enabling the correction of genetic misinformation at the RNA level. This chapter provides an overview of ribozyme-based strategies, highlighting the promises and pitfalls for potential therapeutic applications.
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Affiliation(s)
- Darko Balke
- University of Greifswald, Institute of Biochemistry Felix-Hausdorff-Str. 4 17487 Greifswald Germany
| | - Sabine Müller
- University of Greifswald, Institute of Biochemistry Felix-Hausdorff-Str. 4 17487 Greifswald Germany
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2
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Shen L, Zhou Q, Wang Y, Liao W, Chen Y, Xu Z, Yang L, Sun LQ. Antiangiogenic and antitumoral effects mediated by a vascular endothelial growth factor receptor 1 (VEGFR-1)-targeted DNAzyme. Mol Med 2013; 19:377-86. [PMID: 24306423 DOI: 10.2119/molmed.2013.00090] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/29/2013] [Indexed: 02/05/2023] Open
Abstract
Antiangiogenesis is a promising antitumor strategy that inhibits tumor vascular formation to suppress tumor growth. DNAzymes are synthetic single-strand deoxyribonucleic acid (DNA) molecules that can cleave ribonucleic acids (RNAs). Here, we conducted a comprehensive in vitro selection of active DNAzymes for their activity to cleave the vascular endothelial growth factor receptor (VEGFR-1) mRNA and screened for their biological activity in a matrigel tube-formation assay. Among the selected DNAzymes, DT18 was defined as a lead molecule that was further investigated in several model systems. In a rat corneal vascularization model, DT18 demonstrated significant and specific antiangiogenic activity, as evidenced by the reduced area and vessel number in VEGF-induced corneal angiogenesis. In a mouse melanoma model, DT18 was shown to inhibit B16 tumor growth, whereas it did not affect B16 cell proliferation. We further assessed the DT18 effect in mice with established human nasopharyngeal carcinoma (NPC). A significant inhibition of tumor growth was observed, which accompanied downregulation of VEGFR-1 expression in NPC tumor tissues. To evaluate DT18 effect on vasculature, we performed dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) on the human NPC xenograft mice treated with DT18 and showed a reduction of the parameter of K(trans) (volume constant for transfer of contrast agent), which reflects the condition of tumor microvascular permeability. When examining the safety and tolerability of DT18, intravenous administration of Dz18 to healthy mice caused no substantial toxicities, as shown by parameters such as body weight, liver/kidney function, and histological and biochemical analyses. Taken together, our data suggest that the anti-VEGFR-1 DNAzyme may be used as a therapeutic agent for the treatment of cancer, such as NPC.
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Affiliation(s)
- Liangfang Shen
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Qin Zhou
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ying Wang
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Weihua Liao
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yan Chen
- Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhijie Xu
- Cancer Research Institute, Central South University, Hunan, China
| | - Lifang Yang
- Cancer Research Institute, Central South University, Hunan, China Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lun-Quan Sun
- Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China
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3
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Yu X, Tong Y, Kwok HF, Sze SCW, Zhong L, Lau CBS, Ge W. Anti-angiogenic activity of Erxian Decoction, a traditional Chinese herbal formula, in zebrafish. Biol Pharm Bull 2012; 35:2119-27. [PMID: 23018578 DOI: 10.1248/bpb.b12-00130] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Erxian Decoction (EXD), a traditional Chinese herbal formula, has been used to treat menopausal symptoms and other aging diseases for several decades. Recently, our laboratory found that EXD could inhibit the proliferation of breast cancer cells. This activity may be mediated by anti-angiogenic action. To investigate the anti-angiogenic activity of EXD, its inhibitory effect on blood vessel formation was evaluated using both wild type and transgenic zebrafish embryos with fluorescent vasculature in vivo. Both semi-quantitative and real-time quantitative polymerase chain reaction (qPCR) were carried out to evaluate the effect of EXD on the expression of several genes closely associated with angiogenesis in zebrafish. EXD was found to inhibit vessel formation in zebrafish embryos in a dose- and time-dependent manner. Furthermore, it reduced the mRNA expression of vascular endothelial growth factor A (VEGF-A) and the protein level of hypoxia inducible factor 1α (HIF-1α) in the embryos, suggesting the involvement of HIF-1 mediated VEGF-A signaling pathway in the anti-angiogenic action of EXD. The anti-angiogenic activity of EXD provides new insights to its clinical application and may in the future lead to the development of potential drugs for treating various cancers, especially in menopausal period.
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Affiliation(s)
- Xiaobin Yu
- School of Chinese Medicine, LKS Faculty of Medicine, The University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong, China
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4
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Morrow PK, Murthy RK, Ensor JD, Gordon GS, Margolin KA, Elias AD, Urba WJ, Weng DE, Rugo HS, Hortobagyi GN. An open-label, phase 2 trial of RPI.4610 (Angiozyme) in the treatment of metastatic breast cancer. Cancer 2012; 118:4098-104. [PMID: 22281842 DOI: 10.1002/cncr.26730] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 09/26/2011] [Accepted: 10/13/2011] [Indexed: 12/18/2022]
Abstract
BACKGROUND Serum and plasma levels of vascular endothelial growth factor (VEGF) correlate with prognosis in patients with metastatic breast cancer (MBC). VEGF binds to 2 receptors on endothelial cells, VEGFR-1 and VEGFR-2. RPI.4610 (Angiozyme0) is an antiangiogenic ribozyme targeting the VEGFR-1 mRNA. Preclinical and phase 1 studies suggested that RPI.4610 is a well-tolerated agent with clinical activity in solid tumors. The authors' trial evaluated the efficacy of RPI.4610 in the treatment of patients with progressive MBC. METHODS This phase 2, multicenter, single-arm study was designed to assess the objective response rate of RPI.4610 in patients with MBC who had experienced disease progression with at least 1 course of chemotherapy for MBC. Patients received daily subcutaneous injections of RPI.4610 100 mg/m(2) for 12 weeks. RESULTS Most patients (93%) had received at least 2 lines of chemotherapy previously; 69% of patients had received at least 3 lines of chemotherapy. Median follow-up was 2.76 months (range, 0.89-36.6 months). No partial responses nor complete responses were found. Median progression-free survival was 1.41 months (95% confidence interval [CI], 1.35-1.45). The median overall survival from start of treatment was 11.89 months (95% CI, 4.11-23.66). Treatment-related adverse events (AEs) were primarily grade 1 to 2 in intensity. Most common AEs were: injection site reactions, abdominal pain, anorexia, chromaturia, constipation, dyspnea, fatigue, headache, pain at the injection site, nausea, vomiting, and fever. CONCLUSIONS Although RPI.4610 demonstrated a well-tolerated safety profile, its lack of clinical efficacy precludes this drug from further development.
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Oh EJ, Park K, Choi JS, Joo CK, Hahn SK. Synthesis, characterization, and preliminary assessment of anti-Flt1 peptide–hyaluronate conjugate for the treatment of corneal neovascularization. Biomaterials 2009; 30:6026-34. [DOI: 10.1016/j.biomaterials.2009.07.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 07/14/2009] [Indexed: 10/20/2022]
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6
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Abstract
Although Nature's antisense approaches are clearly impressive, this Perspectives article focuses on the experimental uses of antisense reagents (ASRs) for control of biological processes. ASRs comprise antisense oligonucleotides (ASOs), and their catalytically active counterparts ribozymes and DNAzymes, as well as small interfering RNAs (siRNAs). ASOs and ribozymes/DNAzymes target RNA molecules on the basis of Watson-Crick base pairing in sequence-specific manner. ASOs generally result in destruction of the target RNA by RNase-H mediated mechanisms, although they may also sterically block translation, also resulting in loss of protein production. Ribozymes and DNAzymes cleave target RNAs after base pairing via their antisense flanking arms. siRNAs, which contain both sense and antisense regions from a target RNA, can mediate target RNA destruction via RNAi and the RISC, although they can also function at the transcriptional level. A considerable number of ASRs (mostly ASOs) have progressed into clinical trials, although most have relatively long histories in Phase I/II settings. Clinical trial results are surprisingly difficult to find, although few ASRs appear to have yet established efficacy in Phase III levels. Evolution of ASRs has included: (a) Modifications to ASOs to render them nuclease resistant, with analogous modifications to siRNAs being developed; and (b) Development of strategies to select optimal sites for targeting. Perhaps the biggest barrier to effective therapies with ASRs is the "Delivery Problem." Various liposomal vehicles have been used for systemic delivery with some success, and recent modifications appear to enhance systemic delivery, at least to liver. Various nanoparticle formulations are now being developed which may also enhance delivery. Going forward, topical applications of ASRs would seem to have the best chances for success. In summary, modifications to ASRs to enhance stability, improve targeting, and incremental improvements in delivery vehicles continue to make ASRs attractive as molecular therapeutics, but their advance toward the bedside has been agonizingly slow.
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MESH Headings
- Animals
- Binding Sites/genetics
- DNA, Catalytic/chemistry
- DNA, Catalytic/therapeutic use
- Drug Delivery Systems/methods
- Drug Delivery Systems/trends
- Humans
- Oligonucleotides, Antisense/adverse effects
- Oligonucleotides, Antisense/chemistry
- Oligonucleotides, Antisense/therapeutic use
- Oligonucleotides, Antisense/toxicity
- RNA, Catalytic/chemistry
- RNA, Catalytic/therapeutic use
- RNA, Small Interfering/chemistry
- RNA, Small Interfering/therapeutic use
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Affiliation(s)
- Wei-Hua Pan
- Gittlen Cancer Research Foundation, Hershey Medical Center, Department of Pathology, College of Medicine, Pennsylvania State University, Hershey, Pennsylvania 17033, USA
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7
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Goncalves V, Gautier B, Coric P, Bouaziz S, Lenoir C, Garbay C, Vidal M, Inguimbert N. Rational Design, Structure, and Biological Evaluation of Cyclic Peptides Mimicking the Vascular Endothelial Growth Factor. J Med Chem 2007; 50:5135-46. [PMID: 17900101 DOI: 10.1021/jm0706970] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Angiogenesis is the development of a novel vascular network from a pre-existing structure. Blocking angiogenesis is an attractive strategy to inhibit tumor growth and metastasis formation. Based on structural and mutagenesis data, we have developed novel cyclic peptides that mimic, simultaneously, two regions of the VEGF crucial for the interaction with the VEGF receptors. The peptides, displaying the best affinity for VEGF receptor 1 on a competition assay, inhibited endothelial cell transduction pathway, migration, and capillary-like tubes formation. The specificity of these peptides for VEGF receptors was demonstrated by microscopy using a fluorescent peptide derivative. The resolution of the structure of some cyclic peptides by NMR and molecular modeling has allowed the identification of various factors accounting for their inhibitory activity. Taken together, these results validate the selection of these two regions as targets to develop molecules able to disturb the development of cancer and angiogenesis-associated diseases.
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Affiliation(s)
- Victor Goncalves
- Université Paris Descartes, UFR biomédicale, Laboratoire de Pharmacochimie Moléculaire et Cellulaire, 45 rue des Saints Pères, Paris, F-75006, France
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8
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Tao Y, Kim J, Yin Y, Zafar I, Falk S, He Z, Faubel S, Schrier RW, Edelstein CL. VEGF receptor inhibition slows the progression of polycystic kidney disease. Kidney Int 2007; 72:1358-66. [PMID: 17882148 DOI: 10.1038/sj.ki.5002550] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Although the receptors for vascular endothelial growth factor (VEGF) exert their effects on vasculogenesis and angiogenesis through receptors located on endothelial cells, recent studies have shown that these receptors are also present on renal tubular epithelial cells. We investigated the role of VEGF on increased tubule cell proliferation in the Han:SPRD heterozygous (Cy/+) rat model of polycystic kidney disease. The levels of VEGF in the kidneys and the serum, and the expression of the two receptors on tubules were increased in Cy/+ rats. These rats were given ribozymes that specifically inhibited VEGFR1 and VEGFR2 mRNA expression. Tubule cell proliferation within the cysts was significantly decreased in the ribozyme-treated animals leading to decreased cystogenesis, blunted renal enlargement, and prevented the loss of renal function. Our studies show that inhibition of VEGF function may be an important therapeutic option to delay the progression of polycystic kidney disease.
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Affiliation(s)
- Y Tao
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Amarillo, Texas 79106, USA.
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9
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Yamamoto A, Watanabe H, Sueki H, Nakanishi T, Yasuhara H, Iijima M. Vascular endothelial growth factor receptor tyrosine kinase inhibitor PTK787/ZK 222584 inhibits both the induction and elicitation phases of contact hypersensitivity. J Dermatol 2007; 34:419-29. [PMID: 17584317 DOI: 10.1111/j.1346-8138.2007.00304.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vascular endothelial growth factor (VEGF) and its endothelial cell receptors (VEGFR) have been shown to be involved in the pathogenesis of the contact hypersensitivity (CHS) reaction. Previous studies have demonstrated that anti-VEGFR-2 antibody significantly suppresses the elicitation phase of CHS but does not affect the induction phase. PTK787/ZK 222584 (1-[4-chloroanilino]-4-[4-pyridylmethyl] phthalazine succinate; PTK/ZK) is a potent inhibitor of VEGFR tyrosine kinases. To test the effect of PTK/ZK on the induction and elicitation phases of CHS separately, we used an established method of CHS assay-sensitization and challenge in BALB/c mice. Either 50 mg/kg/day PTK/ZK or vehicle serving as a control was administered orally in the induction or elicitation phases separately. In the afferent phase, flow cytometry of skin-draining lymph node cells revealed that the migration of Langerhans cells was suppressed in the mice treated with PTK/ZK at sensitization. The degrees of ear swelling at 24 and 48 h were significantly diminished in mice treated with PTK/ZK at sensitization (P < 0.05). In the efferent phase, the degrees of ear swelling at 24 h (P < 0.01) and 48 h (P < 0.05), ear blood flow at 24 and 48 h (P < 0.01), and production of VEGF in the epidermis at 24 h (P < 0.05) were significantly suppressed in mice treated with PTK/ZK at elicitation. These findings and previous demonstrations suggest that both VEGF R-1 and VEGF R-2 are needed during the induction phase, and that VEGFR-2 has a pivotal role in the elicitation phase of the CHS reaction.
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Affiliation(s)
- Aisaku Yamamoto
- Department of Dermatology, Showa University School of Medicine, Shinagawa-ku, Tokyo, Japan
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10
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Baka S, Clamp AR, Jayson GC. A review of the latest clinical compounds to inhibit VEGF in pathological angiogenesis. Expert Opin Ther Targets 2007; 10:867-76. [PMID: 17105373 DOI: 10.1517/14728222.10.6.867] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Angiogenesis plays an important role in the formation of new blood vessels and is crucial for tumour development and progression. Imbalance between pro- and antiangiogenesis factors regulates the biological process of angiogenesis. The best characterised of the proangiogenic factors and the most potent is vascular endothelial growth factor (VEGF). The binding of VEGF to one of its transmembrane tyrosine kinase receptors, which are predominantly found on endothelial cells, results in receptor dimerisation, activation and autophosphorylation of the tyrosine kinase domain. This triggers a cascade of complex downstream signalling pathways. Several strategies targeting the VEGF signalling pathway have been developed. These include neutralising antibodies to VEGF (bevacizumab) or VEGF receptors (VEGFRs) (DC101), soluble VEGFR/VEGFR hybrids (VEGF-Trap), and tyrosine kinase inhibitors of VEGFRs (BAY43-9006, SU11248, ZD6474, AZD2171, PTK/ZK and others). Several of these agents are now being investigated in clinical trials.
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Affiliation(s)
- Sofia Baka
- Christie Hospital, Manchester, M20 4BX, UK.
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11
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Kiselyov A, Balakin KV, Tkachenko SE. VEGF/VEGFR signalling as a target for inhibiting angiogenesis. Expert Opin Investig Drugs 2007; 16:83-107. [PMID: 17155856 DOI: 10.1517/13543784.16.1.83] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
VEGFs and a respective family of tyrosine kinases receptors (VEGFRs) are key proteins modulating angiogenesis, the formation of new vasculature from an existing vascular network. There has been considerable evidence in vivo, including clinical observations, that abnormal angiogenesis is implicated in a number of disease conditions, which include rheumatoid arthritis, inflammation, cancer, psoriasis, degenerative eye conditions and others. Antiangiogenic therapies based on inhibition of VEGF/VEGFR signalling were reported to be powerful clinical strategies in oncology and ophthalmology. Current efforts have yielded promising clinical data for several antiangiogenic therapeutics. In this review, the authors elucidate key aspects of VEGFR signalling, as well as clinically relevant strategies for the inhibition of VEGF-induced angiogenesis, with an emphasis on small-molecule VEGFR inhibitors.
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Affiliation(s)
- Alex Kiselyov
- ChemDiv, Inc., 11558 Sorrento Valley Road, Suite 5, San Diego, CA 92121, USA.
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12
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Quesada AR, Muñoz-Chápuli R, Medina MA. Anti-angiogenic drugs: from bench to clinical trials. Med Res Rev 2006; 26:483-530. [PMID: 16652370 DOI: 10.1002/med.20059] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Angiogenesis, the generation of new capillaries through a process of pre-existing microvessel sprouting, is under stringent control and normally occurs only during embryonic and post-embryonic development, reproductive cycle, and wound repair. However, in many pathological conditions (solid tumor progression, metastasis, diabetic retinopathy, hemangioma, arthritis, psoriasis and atherosclerosis among others), the disease appears to be associated with persistent upregulated angiogenesis. The development of specific anti-angiogenic agents arises as an attractive therapeutic approach for the treatment of cancer and other angiogenesis-dependent diseases. The formation of new blood vessels is a complex multi-step process. Endothelial cells resting in the parent vessels are activated by an angiogenic signal and stimulated to synthesize and release degradative enzymes allowing endothelial cells to migrate, proliferate and finally differentiate to give rise to capillary tubules. Any of these steps may be a potential target for pharmacological intervention. In spite of the disappointing results obtained initially in clinical trials with anti-angiogenic drugs, recent reports with positive results in phases II and III trials encourage expectations in their therapeutic potential. This review discusses the current approaches for the discovery of new compounds that inhibit angiogenesis, with emphasis on the clinical developmental status of anti-angiogenic drugs.
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Affiliation(s)
- Ana R Quesada
- Department of Molecular Biology and Biochemistry, Faculty of Science, University of Málaga, 29071 Málaga, Spain.
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13
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Affiliation(s)
- J Heidemann
- Department of Medicine B, University of Münster, Albert-Schweitzer-Strasse 33, D-48129 Münster, Germany.
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14
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Abstract
Sustained angiogenesis is one of the hallmarks of carcinogenesis. Vascular endothelial growth factor (VEGF) is a crucial molecule mediating proangiogenic signals against which a number of therapeutic approaches have been designed, such as monoclonal antibodies, small-molecule receptor kinase inhibitors, and nucleic acid inhibitors. The VEGF signaling pathway as a target in lung cancer therapy was validated by a randomized phase III study of platinum agent-based combination chemotherapy with or without bevacizumab, a recombinant humanized monoclonal antibody against VEGF-A, in first-line, nonsquamous, metastatic non-small-cell lung cancer. This trial demonstrated an improvement in overall survival among patients who received bevacizumab in comparison with those who received carboplatin and paclitaxel alone. In this review, we will discuss various aspects of this pivotal trial and highlight issues relevant to angiogenesis inhibition in the treatment of non-small-cell lung cancer.
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Affiliation(s)
- Grace K Dy
- Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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15
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Fahmy RG, Waldman A, Zhang G, Mitchell A, Tedla N, Cai H, Geczy CR, Chesterman CN, Perry M, Khachigian LM. Suppression of vascular permeability and inflammation by targeting of the transcription factor c-Jun. Nat Biotechnol 2006; 24:856-63. [PMID: 16823369 DOI: 10.1038/nbt1225] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 05/26/2006] [Indexed: 01/20/2023]
Abstract
Conventional anti-inflammatory strategies induce multiple side effects, highlighting the need for novel targeted therapies. Here we show that knockdown of the basic-region leucine zipper protein, c-Jun, by a catalytic DNA molecule, Dz13, suppresses vascular permeability and transendothelial emigration of leukocytes in murine models of vascular permeability, inflammation, acute inflammation and rheumatoid arthritis. Treatment with Dz13 reduced vascular permeability due to cutaneous anaphylactic challenge or VEGF administration in mice. Dz13 also abrogated monocyte-endothelial cell adhesion in vitro and abolished leukocyte rolling, adhesion and extravasation in a rat model of inflammation. Dz13 suppressed neutrophil infiltration in the lungs of mice challenged with endotoxin, a model of acute inflammation. Finally, Dz13 reduced joint swelling, inflammatory cell infiltration and bone erosion in a mouse model of rheumatoid arthritis. Mechanistic studies showed that Dz13 blocks cytokine-inducible endothelial c-Jun, E-selectin, ICAM-1, VCAM-1 and VE-cadherin expression but has no effect on JAM-1, PECAM-1, p-JNK-1 or c-Fos. These findings implicate c-Jun as a useful target for anti-inflammatory therapies.
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Affiliation(s)
- Roger G Fahmy
- Centre for Vascular Research, University of New South Wales, and Department of Haematology, The Prince of Wales Hospital, Sydney NSW 2031, Australia
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16
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Nieder C, Wiedenmann N, Andratschke N, Molls M. Current status of angiogenesis inhibitors combined with radiation therapy. Cancer Treat Rev 2006; 32:348-64. [PMID: 16713103 DOI: 10.1016/j.ctrv.2006.03.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 03/27/2006] [Accepted: 03/27/2006] [Indexed: 02/06/2023]
Abstract
Angiogenesis inhibitors combined with cytotoxic chemotherapy have recently entered routine oncological practice. Several rationales exist for combining these agents with ionizing radiation, a primary curative cancer treatment, either in bimodal or trimodal fashion, i.e. with or without additional chemotherapy. More than 20 different anti-angiogenic agents have been studied in preclinical animal tumor models. This systematic review compares the results of preclinical studies published before February 2006. The combination of vascular endothelial growth factor (VEGF) inhibitors with irradiation consistently resulted in improved tumor growth delay (at least additive effects), despite different radiation schedules, drugs and doses, and combination regimens. Only two studies evaluated tumor control dose (TCD)50 as a measure of tumor cure (radiation dose yielding permanent local control in 50% of the tumors). While anti-VEGF receptor (VEGFR) antibody treatment improved the outcome, a VEGFR tyrosine kinase inhibitor showed negative results. For agents interfering with other pathways, the results are also not consistent, although most studies were positive. Trimodal approaches seem to improve tumor growth delay even further. Importantly, both radiotherapy schedule and sequence of the modalities in combined treatment may impact on the outcome. Hence, further preclinical studies examining these parameters need to be conducted. While preclinical research is ongoing, phase I and II clinical trials with bevacizumab, combretastatin A-4, thalidomide and different receptor tyrosine kinase inhibitors, usually combined with radio- and chemotherapy, have been designed. Early results suggest that acute toxicity is acceptable, planned surgery after such treatment is feasible, and that further evaluation of such combined modality treatment is warranted.
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Affiliation(s)
- Carsten Nieder
- Department of Radiation Oncology, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
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17
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Abstract
The discovery that nucleic acids mediated the inhibition of gene expression in a sequence-specific manner has provided the scientific community with a potentially important tool to analyse gene function and validate drug targets. Selective inhibition of gene expression by ribozymes and small interfering RNAs (siRNAs) is being explored for potential therapeutics against viral infections, inflammatory disorders, haematological diseases and cancer. In order to be used as pharmaceutical drugs, chemical modifications are necessary to increase their stability in vivo. However, such modifications should not affect either the ribozyme cleavage activity or the incorporation of the siRNAs into the RNA interference (RNAi) targeting complex and subsequent mRNA cleavage. To attain stability, ribozymes and siRNAs must also overcome several other problems, including accessibility to target messenger RNAs (mRNAs), efficient delivery to target cells and unwanted non-specific effects.
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Affiliation(s)
- M Sioud
- Institute for Cancer Research, Department of Immunology, Molecular Medicine Group, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway.
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18
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Abstract
Abnormal gene expression is a hallmark of many diseases. Gene-specific downregulation of aberrant genes could be useful therapeutically and potentially less toxic than conventional therapies due its specificity. Over the years, many strategies have been proposed for silencing gene expression in a gene-specific manner. Three major approaches are antisense oligonucleotides (AS-ONs), ribozymes/DNAzymes, and RNA interference (RNAi). In this brief review, we will discuss the successes and shortcomings of these three gene-silencing methods, and the approaches being taken to improve the effectiveness of antisense molecules. We will also provide an overview of some of the clinical applications of antisense therapy.
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Affiliation(s)
- A Kalota
- Division of Hematology/Oncology, Department of Medicine, University of Pennsylvania, 421 Curie Blvd, Philadelphia PA, 19104, USA
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19
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Gee MFW, Tsuchida R, Eichler-Jonsson C, Das B, Baruchel S, Malkin D. Vascular endothelial growth factor acts in an autocrine manner in rhabdomyosarcoma cell lines and can be inhibited with all-trans-retinoic acid. Oncogene 2005; 24:8025-37. [PMID: 16116481 DOI: 10.1038/sj.onc.1208939] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Vascular endothelial growth factor (VEGF) is a potent signalling molecule that acts through two tyrosine kinase receptors, VEGFR1 and VEGFR2. The upregulation of VEGF and its receptors is important in tumour-associated angiogenesis; however, recent studies suggest that several tumour cells express VEGF receptors and may be influenced by autocrine VEGF signalling. Rhabdomyosarcoma (RMS) is the most common paediatric soft-tissue sarcoma, and is dependent on autocrine signalling for its growth. The alveolar subtype of RMS is often characterized by the presence of a PAX3-FKHR translocation, and when introduced into non-RMS cells, the resultant fusion protein induces expression of VEGFR1. In our study, we examined the expression of VEGF and its receptors in RMS, and autocrine effects of VEGF on cell growth. VEGF and receptor mRNA and protein were found to be expressed in RMS cells. Exogenous VEGF addition resulted in extracellular signal-regulated kinase-1/2 phosphorylation and cell proliferation, and both were reduced by VEGFR1 blockade. Growth was also slowed by VEGFR1 inhibitor alone. Treatment of RMS cells with all-trans-retinoic acid decreased VEGF secretion and slowed cell growth, which was rescued by VEGF. These data suggest that autocrine VEGF signalling likely influences RMS growth and its inhibition may be an effective treatment for RMS.
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MESH Headings
- Autocrine Communication/drug effects
- Autocrine Communication/physiology
- Blotting, Western
- Cell Count
- Cell Culture Techniques
- Cell Division/drug effects
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Cell Survival/drug effects
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Fluorescent Antibody Technique, Indirect
- Gene Expression Regulation, Neoplastic/drug effects
- HeLa Cells
- Humans
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Phosphorylation/drug effects
- RNA, Messenger/analysis
- Recombinant Proteins/metabolism
- Recombinant Proteins/pharmacology
- Reverse Transcriptase Polymerase Chain Reaction
- Rhabdomyosarcoma, Alveolar/genetics
- Rhabdomyosarcoma, Alveolar/metabolism
- Rhabdomyosarcoma, Alveolar/pathology
- Rhabdomyosarcoma, Embryonal/genetics
- Rhabdomyosarcoma, Embryonal/metabolism
- Rhabdomyosarcoma, Embryonal/pathology
- Tretinoin/pharmacology
- Umbilical Veins/cytology
- Vascular Endothelial Growth Factor A/genetics
- Vascular Endothelial Growth Factor A/metabolism
- Vascular Endothelial Growth Factor A/pharmacology
- Vascular Endothelial Growth Factor Receptor-1/genetics
- Vascular Endothelial Growth Factor Receptor-1/metabolism
- Vascular Endothelial Growth Factor Receptor-2/genetics
- Vascular Endothelial Growth Factor Receptor-2/metabolism
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Affiliation(s)
- Matthew F W Gee
- Division of Haematology/Oncology, Department of Paediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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20
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Thamm DH, Dickerson EB, Akhtar N, Lewis R, Auerbach R, Helfand SC, MacEwen EG. Biological and molecular characterization of a canine hemangiosarcoma-derived cell line. Res Vet Sci 2005; 81:76-86. [PMID: 16256156 DOI: 10.1016/j.rvsc.2005.09.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 08/24/2005] [Accepted: 09/06/2005] [Indexed: 10/25/2022]
Abstract
Canine hemangiosarcoma (HSA) is a devastating disease. Investigation of novel therapies has been limited by the limited availability of canine HSA-derived cell lines. We report the development of a canine HSA-derived cell line, DEN-HSA, which recapitulates features of angiogenic endothelium. DEN-HSA cells were derived from a spontaneous HSA arising in the kidney of a dog. DEN-HSA displayed surface molecules distinctive of endothelial histogenesis, including factor VIII-related antigen, ICAM-1 and alpha(v)beta3 integrin. In vitro, DEN-HSA formed microvascular tube-like structures on Matrigel, and proliferated in response to a variety of angiogenic growth factors. The cells expressed mRNA and protein specific for bFGF and its receptors, and VEGF and its receptors, among others. DEN-HSA conditioned medium evoked a marked angiogenic response in a murine corneal pocket assay, indicating potent proangiogenic activity of substances secreted by this cell line. This research confirms the DEN-HSA cell line as endothelial in origin, suggests the presence of angiogenic growth factor autocrine loops, and offers the potential to utilize DEN-HSA cells for the study of novel therapies that modulate endothelial proliferation.
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Affiliation(s)
- Douglas H Thamm
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 53706, USA.
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21
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Weng DE, Masci PA, Radka SF, Jackson TE, Weiss PA, Ganapathi R, Elson PJ, Capra WB, Parker VP, Lockridge JA, Cowens JW, Usman N, Borden EC. A phase I clinical trial of a ribozyme-based angiogenesis inhibitor targeting vascular endothelial growth factor receptor-1 for patients with refractory solid tumors. Mol Cancer Ther 2005; 4:948-55. [PMID: 15956252 DOI: 10.1158/1535-7163.mct-04-0210] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE This study intended to determine the maximum tolerated dose, safety, pharmacokinetic variables, clinical response, and pharmacodynamic markers of daily s.c. administration of Angiozyme. PATIENTS AND METHODS Patients with refractory solid tumors were enrolled in a dose escalation and expanded cohort design. Dose escalation involved cohorts of patients at doses of 10, 30, 100, or 300 mg/m(2)/d for 29 days. A second component enrolled 15 additional patients at a daily dose of 100 mg/m(2). Patients were eligible to continue on therapy until disease progression. RESULTS Thirty-one patients were enrolled and 28 were evaluable (range, 29-505 days; median, 89.5 days). A maximum tolerated dose was not defined by toxicity but rather by the maximal deliverable dose of 300 mg/m(2)/d. Grade 1 to 2 injection site reactions were the most common toxicities. One patient in the 300 mg/m(2) group experienced a reversible grade 3 injection site reaction. Angiozyme showed dose-dependent plasma concentrations with good bioavailability. Surrogate markers showed Angiozyme localization in tumor biopsies and a significant increase in serum von Willebrand factor antigen, a marker for endothelial cell dysfunction. Although Angiozyme-reactive antibody production was noted for some patients, no antibody-related adverse events were noted. Seven of 28 (25%) evaluable patients had stable disease for >or =6 months, with the longest treatment duration of > or =16 months. Two patients (nasopharyngeal carcinoma and melanoma) showed minor responses. CONCLUSION Angiozyme was well tolerated with satisfactory pharmacokinetic variables for daily s.c. dosing. Results have provided the basis for subsequent clinical trials of this first-of-class biologically targeted therapeutic.
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Affiliation(s)
- David E Weng
- Taussig Cancer Center, Cleveland Clinic Foundation, OH 44195, USA.
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22
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Kobayashi H, Eckhardt SG, Lockridge JA, Rothenberg ML, Sandler AB, O'Bryant CL, Cooper W, Holden SN, Aitchison RD, Usman N, Wolin M, Basche ML. Safety and pharmacokinetic study of RPI.4610 (ANGIOZYME), an anti-VEGFR-1 ribozyme, in combination with carboplatin and paclitaxel in patients with advanced solid tumors. Cancer Chemother Pharmacol 2005; 56:329-36. [PMID: 15906031 DOI: 10.1007/s00280-004-0968-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Accepted: 09/14/2004] [Indexed: 11/25/2022]
Abstract
PURPOSE RPI.4610 (ANGIOZYME) is a chemically stabilized ribozyme targeting vascular endothelial growth factor receptor 1. The purpose of this study was to evaluate the safety and pharmacokinetics of RPI.4610 in combination with carboplatin and paclitaxel in patients with advanced solid tumors. METHODS The study used a sequential treatment design evaluating a single dose level for all three drugs: paclitaxel 175 mg m-2 and carboplatin AUC=6 on day 1 of a 21-day cycle, and RPI.4610 100 mg m-2 day-1 beginning on day 8 and continuing daily thereafter. Pharmacokinetic samples were drawn on day 1 of courses 1 (chemotherapy alone) and 2 (chemotherapy+RPI.4610), and on day 8 of course 1 (RPI.4610 alone). Ratios were generated by comparing the pharmacokinetic parameters for the combination of carboplatin with paclitaxel when administered alone or together with RPI.4610. RESULTS Twelve patients were enrolled in this trial and received two to six courses of treatment each. The most common grade 3-4 toxicities were neutropenia (three patients), thrombocytopenia (three patients), pain (three patients), anemia (two patients) and fatigue (two patients). The ratio of the mean maximum plasma concentration (Cmax) for carboplatin when administered with paclitaxel alone versus when administered with paclitaxel and RPI.4610 was 1.07 (90% confidence interval, 0.77-1.37). Similarly, the ratio of the mean AUC0-last for carboplatin was 1.04 (0.73-1.35). For paclitaxel the ratio of the mean Cmax when administered with carboplatin alone versus with carboplatin and RPI.4610 was 1.17 (1.03-1.31), and the ratio of the mean AUC0-last was 1.17 (1.04-1.30). Objective tumor responses were observed and included one patient with a complete response (bladder cancer) and one patient with a partial response (esophageal cancer). CONCLUSIONS These results indicate that RPI.4610, carboplatin, and paclitaxel can be administered safely in combination without substantial pharmacokinetic interactions.
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Affiliation(s)
- Hiroyuki Kobayashi
- Vanderbilt-Ingram Cancer Center, 777 Preston Research Building, Nashville, TN 37232-6307, USA
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23
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Bae DG, Kim TD, Li G, Yoon WH, Chae CB. Anti-Flt1 Peptide, a Vascular Endothelial Growth Factor Receptor 1–Specific Hexapeptide, Inhibits Tumor Growth and Metastasis. Clin Cancer Res 2005; 11:2651-61. [PMID: 15814646 DOI: 10.1158/1078-0432.ccr-04-1564] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The purpose of this study was to develop antagonists specific for the vascular endothelial growth factor receptor 1 (VEGFR1) and to investigate the effects of the antagonists on the VEGF-induced endothelial cell functions and tumor progression. EXPERIMENTAL DESIGN Hexapeptides that inhibit binding of VEGFR1 and VEGF were identified through screening of synthetic peptide library. A selected peptide, anti-Flt1, was investigated for binding specificity with various receptors and ligand peptides. Effects of the peptide on proliferation, cell migration, and fibrin gel-based angiogenesis of endothelial cells were also investigated. The activity of anti-Flt1, in vivo, was evaluated for inhibition of tumor growth and metastasis in VEGF-secreting cancer cell-implanted mice by s.c. injections of the peptide. RESULTS Here, we report on a short peptide that binds to VEGFR1 and prevents binding of VEGF. A hexapeptide, anti-Flt1 (Gly-Asn-Gln-Trp-Phe-Ile or GNQWFI), was identified from peptide libraries. The anti-Flt1 peptide shows specificity toward binding to VEGFR1 and it inhibits binding of VEGF, placental growth factor (PlGF), and VEGF/PlGF heterodimer to VEGFR1. This peptide does not inhibit the proliferation of endothelial cells induced by VEGF and VEGF/PlGF heterodimer but it effectively blocks VEGF-induced migration of endothelial cells and their capacity to form capillary-like structures on fibrin gel-based in vitro angiogenesis system. Furthermore, growth and metastasis of VEGF-secreting tumor cells were also significantly inhibited by s.c. injections of anti-Flt1 peptide in nude mice. Accordingly, VEGF-induced migration and capillary formation are mediated through VEGFR1, and these processes may play an important role in the growth and metastasis of VEGF-secreting tumors. CONCLUSIONS We show that a peptide (anti-Flt1) specific for VEGFR1 inhibits growth and metastasis of tumor that secretes VEGF. The effects on endothelial cell functions, in vitro, indicate that the anticancer activity of anti-Flt1 peptide with reduced blood vessel density could also be due to the blocking of VEGFR1-mediated endothelial cell migration and tube formation. Although the effects of anti-Flt1 peptide still remain to be further characterized, the receptor 1-specific peptide antagonist, anti-Flt1, has potential as a therapeutic agent for various angiogenesis-related diseases, especially cancer.
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Affiliation(s)
- Dong-Goo Bae
- Department of Life Science, Division of Molecular and Life Sciences, Postech Biotech Center, Pohang University of Science and Technology, Pohang, Korea
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24
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Huh JI, Calvo A, Stafford J, Cheung M, Kumar R, Philp D, Kleinman HK, Green JE. Inhibition of VEGF receptors significantly impairs mammary cancer growth in C3(1)/Tag transgenic mice through antiangiogenic and non-antiangiogenic mechanisms. Oncogene 2005; 24:790-800. [PMID: 15592523 DOI: 10.1038/sj.onc.1208221] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cancer growth and progression is often critically influenced by the production of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis. VEGF produced by tumor cells stimulates endothelial cell growth through the binding and activation of the KDR/Flk-1 receptor (VEGFR-2) on endothelial cells. Recently, some human breast cancer epithelial cells have been shown to express VEGF receptors, suggesting a potential autocrine-mediated growth stimulation of a subset of cancers by VEGF. We demonstrate that mammary tumors in the C3(1)/Tag transgenic model express VEGF and VEGF receptors and tumor growth is stimulated by this autocrine mechanism. GW654652, an indazolylpyrimidine, is a VEGFRs tyrosine kinase inhibitor that dramatically reduces both angiogenesis and tumor cell growth in this model, as demonstrated using both in vitro and in vivo assays. GW654652 significantly decreased cell proliferation and induced apoptosis in human umbilical vein endothelial cells and M6 mammary tumor cells derived from C3(1)/Tag (Tag: simian virus 40 T-antigen) transgenic mice. A 75% reduction in VEGF-induced angiogenesis was observed with GW654652 using the chick chorioallantoic membrane assay, whereas GW654652 produced an approximately 85% reduction in angiogenesis as assessed by the Matrigel plug assay. A profound inhibitory effect on tumor growth in the C3(1)/Tag transgenic model of human breast cancer was observed with oral administration of GW654652 as measured by delayed tumor onset, decreased multiplicity, reduced tumor volume, and extended animal survival. The antitumor effects of GW654652 were associated with reduced tumor vascularization and no apparent toxicity. Tumor growth, however, rapidly advanced following cessation of treatment. This is the first demonstration that a VEGF receptor inhibitor, GW654652, has a strong inhibitory effect on angiogenesis and tumor progression in a transgenic model of mammary cancer, suggesting that this is a useful approach for preclinical testing of such agents.
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Affiliation(s)
- Jung-Im Huh
- Laboratory of Cell Regulation and Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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25
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Ebbinghaus SW, Gordon MS. Renal cell carcinoma: rationale and development of therapeutic inhibitors of angiogenesis. Hematol Oncol Clin North Am 2004; 18:1143-59, ix-x. [PMID: 15474339 DOI: 10.1016/j.hoc.2004.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Inhibition of tumor angiogenesis is a promising therapeutic approach to treat cancer; translation of this concept into clinical practice requires an understanding of the molecular events that are responsible for the development of tumor vasculature. Renal cell carcinoma is characterized by the frequent loss of the von Hippel-Lindau tumor suppressor gene which results in the loss of one of the critical mechanisms for regulating the level of hypoxia inducible factor 1 and leads to the overproduction of vascular endothelial growth factor (VEGF) by the tumor cell. Therapeutic strategies to inhibit the function of these important pathways have been effective in preventing tumor angiogenesis in preclinical models of kidney cancer, and more recently, in the clinical setting. Strategies to treat renal cell carcinoma with agents that are designed to prevent angiogenesis have included interruption of the VEGF signaling pathway, mimics of endogenous angiogenesis inhibitors, prevention of destruction of the basement membrane, and direct inhibition of endothelial cells by a variety of agents with complex, novel, or undetermined mechanisms. Recent clinical studies of bevacizumab, the first anti-VEGF agent to be marketed for the treatment of cancer, have provided proof for the concept that these strategies can lead to tangible benefits for patients who have advanced renal cell carcinoma and likely will be applicable broadly to the treatment of cancer.
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Affiliation(s)
- Scot W Ebbinghaus
- Division of Hematology-Oncology, University of Arizona College of Medicine, Arizona Cancer Center, 1515 North Campbell Avenue, Tucson, AZ 85724-5024, USA.
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26
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Zhang G, Dass CR, Sumithran E, Di Girolamo N, Sun LQ, Khachigian LM. Effect of deoxyribozymes targeting c-Jun on solid tumor growth and angiogenesis in rodents. J Natl Cancer Inst 2004; 96:683-96. [PMID: 15126605 DOI: 10.1093/jnci/djh120] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The basic region-leucine zipper protein c-Jun has been linked to cell proliferation, transformation, and apoptosis. However, a direct role for c-Jun in angiogenesis has not been shown. METHODS We used human microvascular endothelial cells (HMEC-1) transfected with a DNAzyme targeting the c-Jun mRNA (Dz13), related oligonucleotides, or vehicle in in vitro models of microvascular endothelial cell proliferation, migration, chemoinvasion, and tubule formation, a rat model of corneal neovascularization, and a mouse model of solid tumor growth and vascular endothelial growth factor (VEGF)-induced angiogenesis. All statistical tests were two-sided. RESULTS Compared with mock-transfected cells, HMEC-1 cells transfected with Dz13 expressed less c-Jun protein and possessed lower DNA-binding activity. Dz13 blocked endothelial cell proliferation, migration, chemoinvasion, and tubule formation. Dz13 inhibited the endothelial cell expression and proteolytic activity of MMP-2, a c-Jun-dependent gene. Dz13 inhibited VEGF-induced neovascularization in the rat cornea compared with vehicle control (Dz13 versus vehicle: 4.0 neovessels versus 30.7 neovessels, difference = 26.7 neovessels; P =.004; area occupied by new blood vessels for Dz13 versus vehicle: 0.35 mm2 versus 1.52 mm2, difference = 1.17 mm2; P =.005) as well as solid melanoma growth in mice (Dz13 versus vehicle at 14 days: 108 mm3 versus 283 mm3, difference = 175 mm3; P =.006) with greatly reduced vascular density (Dz13 versus vehicle: 30% versus 100%, difference = 70%; P<.001). CONCLUSION DNAzymes targeting c-Jun may have therapeutic potential as inhibitors of tumor angiogenesis and growth.
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MESH Headings
- Angiogenesis Inhibitors/pharmacology
- Animals
- Antineoplastic Agents/pharmacology
- Blotting, Western
- Cell Division
- Cell Line
- Cell Movement
- Cornea/blood supply
- DNA, Catalytic/pharmacology
- Electrophoresis, Polyacrylamide Gel
- Endothelial Cells
- Female
- Gene Expression Regulation, Neoplastic/drug effects
- Genes, jun/drug effects
- Humans
- Male
- Matrix Metalloproteinase 2/metabolism
- Matrix Metalloproteinase Inhibitors
- Melanoma, Experimental/drug therapy
- Melanoma, Experimental/enzymology
- Mice
- Mice, Inbred C57BL
- Neovascularization, Pathologic/drug therapy
- Neovascularization, Pathologic/enzymology
- Proto-Oncogene Proteins c-jun/drug effects
- Proto-Oncogene Proteins c-jun/genetics
- Proto-Oncogene Proteins c-jun/metabolism
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Transfection
- Vascular Endothelial Growth Factor A
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Affiliation(s)
- Guishui Zhang
- Centre for Vascular Research, The University of New South Wales and Department of Haematology, The Prince of Wales Hospital, Sydney, Australia
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27
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Abstract
This review examines applications of nucleic acid technology in the form of catalytic nucleic acids (ribozymes and DNAzymes) and RNA interference (RNAi) in the CNS. The basic mechanism of catalytic nucleic acids and RNAi is reviewed, and potentials and problems highlighted. Recent advances in chemical modifications and delivery techniques are summarized. Applications in the CNS, including their use in primary neuronal cells, organotypic slice culture and the brain in vivo are further discussed.
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Affiliation(s)
- Barbara Trülzsch
- Department of Human Anatomy and Genetics, South Parks Road, Oxford, UK.
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28
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Wheeler YY, Kute TE, Willingham MC, Chen SY, Sane DC. Intrabody-based strategies for inhibition of vascular endothelial growth factor receptor-2: effects on apoptosis, cell growth, and angiogenesis. FASEB J 2003; 17:1733-5. [PMID: 12958192 DOI: 10.1096/fj.02-0942fje] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
VEGF, an endothelial-specific mitogen, is an important tumor angiogenesis growth factor. The major receptor for VEGF on endothelial cells is KDR. We hypothesized that an intrabody could bind newly synthesized KDR and block receptor transport to the cell surface, thereby inhibiting important VEGF effects. We expressed a single chain antibody (p3S5) to KDR with or without the endoplasmic reticulum (ER) retention signal (KDEL), using either a plasmid (p3S5-HAK) or a tet-off adenoviral system (Ad-HAK). Plasmid-mediated expression of the tethered intrabody significantly reduced KDR expression (from 82.5+/-12.5% to 27.9+/-13.6% of cells; P<0.01) and thymidine incorporation in successfully transfected cells. Ad-HAK infection resulted in intrabody expression in >90% of human umbilical vein endothelial cells (HUVECs), producing marked (80%) apoptosis at 48 h postinfection. The intrabody was essential for these effects, as confirmed by inhibiting its expression with doxycycline or by expressing irrelevant genes (lacZ, GFP). Cell death was dependent on KDR, because Ad-HAK infection of cell lines with minimal or no KDR had little effect on cell viability. Infected HUVECs were unable to form tubes on Engelbreth Holm-Swarm (EHS) tumor gel matrix. These results demonstrate the potential for development of an intrabody-based strategy to block angiogenesis and prevent tumor growth.
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Affiliation(s)
- Yurong Yang Wheeler
- Section of Cardiology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1045, USA
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29
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Steele D, Kertsburg A, Soukup GA. Engineered catalytic RNA and DNA : new biochemical tools for drug discovery and design. AMERICAN JOURNAL OF PHARMACOGENOMICS : GENOMICS-RELATED RESEARCH IN DRUG DEVELOPMENT AND CLINICAL PRACTICE 2003; 3:131-44. [PMID: 12749730 DOI: 10.2165/00129785-200303020-00006] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Since the fundamental discovery that RNA catalyzes critical biological reactions, the conceptual and practical utility of nucleic acid catalysts as molecular therapeutic and diagnostic agents continually develops. RNA and DNA catalysts are particularly attractive tools for drug discovery and design due to their relative ease of synthesis and tractable rational design features. Such catalysts can intervene in cellular or viral gene expression by effectively destroying virtually any target RNA, repairing messenger RNAs derived from mutant genes, or directly disrupting target genes. Consequently, catalytic nucleic acids are apt tools for dissecting gene function and for effecting gene pharmacogenomic strategies. It is in this capacity that RNA and DNA catalysts have been most widely utilized to affect gene expression of medically relevant targets associated with various disease states, where a number of such catalysts are presently being evaluated in clinical trials. Additionally, biotechnological prospects for catalytic nucleic acids are seemingly unlimited. Controllable nucleic acid catalysts, termed allosteric ribozymes or deoxyribozymes, form the basis of effector or ligand-dependent molecular switches and sensors. Allosteric nucleic acid catalysts promise to be useful tools for detecting and scrutinizing the function of specified components of the metabolome, proteome, transcriptome, and genome. The remarkable versatility of nucleic acid catalysis is thus the fountainhead for wide-ranging applications of ribozymes and deoxyribozymes in biomedical and biotechnological research.
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Affiliation(s)
- David Steele
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, USA
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30
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Sho E, Komatsu M, Sho M, Nanjo H, Singh TM, Xu C, Masuda H, Zarins CK. High flow drives vascular endothelial cell proliferation during flow-induced arterial remodeling associated with the expression of vascular endothelial growth factor. Exp Mol Pathol 2003; 75:1-11. [PMID: 12834620 DOI: 10.1016/s0014-4800(03)00032-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Endothelial cell activation and proliferation are the essential steps in flow-induced arterial remodeling. We investigated endothelial cell turnover in the early stages of high-flow in the rabbit common carotid arteries using an arteriovenous fistula (AVF) model by kinetic investigation of cell proliferation and cell molecular analysis. BrdU was administrated to label endothelial cells (ECs) in DNA synthetic phase (S-phase) of the cell mitotic cycle. Pulse labeling revealed that ECs entered S-phase at 1.5 days of AVF (0.93 +/- 0.19%). Endothelial cell labeling index (EC-LI) peaked at 2 days of AVF (8.90 +/- 0.87%) with a high index of endothelial cell mitosis (EC-MI, 1.67 +/- 0.47%). Endothelial cell density increased remarkably at 3 days of AVF with a significant decrease in EC-LI (54%) and EC-MI (60%). Study of kinetics of EC proliferation revealed that endothelial cells took 16-24 h to finish one cycle of cell mitosis. Tracking investigation of pulse BrdU-labeled endothelial cells at 1.5 days showed that more than 66% of endothelial cells were BrdU-labeled 1.5 days after labeling. VEGF, integrin alphanubeta3, PECAM-1, and VE-cadherin were upregulated significantly preceding endothelial cell proliferation and kept at high levels during endothelial cell proliferation. These data suggest that endothelial cell proliferation is the initial step in flow-induced arterial remodeling. Hemodynamic forces may drive endothelial cell downstream migration. Expression of VEGF and cell junction molecules contribute to flow-induced arterial remodeling.
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Affiliation(s)
- Eiketsu Sho
- Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305-5642, USA.
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31
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Fahmy RG, Dass CR, Sun LQ, Chesterman CN, Khachigian LM. Transcription factor Egr-1 supports FGF-dependent angiogenesis during neovascularization and tumor growth. Nat Med 2003; 9:1026-32. [PMID: 12872165 DOI: 10.1038/nm905] [Citation(s) in RCA: 286] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2003] [Accepted: 06/27/2003] [Indexed: 11/08/2022]
Abstract
Current understanding of key transcription factors regulating angiogenesis is limited. Here we show that RNA-cleaving phosphodiester-linked DNA-based enzymes (DNAzymes), targeting a specific motif in the 5' untranslated region of early growth response (Egr-1) mRNA, inhibit Egr-1 protein expression, microvascular endothelial cell replication and migration, and microtubule network formation on basement membrane matrices. Egr-1 DNAzymes blocked angiogenesis in subcutaneous Matrigel plugs in mice, an observation that was independently confirmed by plug analysis in Egr-1-deficient animals, and inhibited MCF-7 human breast carcinoma growth in nude mice. Egr-1 DNAzymes suppressed tumor growth without influencing body weight, wound healing, blood coagulation or other hematological parameters. These agents inhibited endothelial expression of fibroblast growth factor (FGF)-2, a proangiogenic factor downstream of Egr-1, but not that of vascular endothelial growth factor (VEGF). Egr-1 DNAzymes also repressed neovascularization of rat cornea. Thus, microvascular endothelial cell growth, neovascularization, tumor angiogenesis and tumor growth are processes that are critically dependent on Egr-1.
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MESH Headings
- Animals
- Breast Neoplasms
- Cell Division/physiology
- Cell Movement/physiology
- DNA, Catalytic/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Early Growth Response Protein 1
- Endothelial Growth Factors/metabolism
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- Female
- Fibroblast Growth Factor 2/metabolism
- Humans
- Immediate-Early Proteins
- Intercellular Signaling Peptides and Proteins/metabolism
- Lymphokines/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Nude
- Microtubules/metabolism
- Neoplasm Transplantation/pathology
- Neoplasms, Experimental/blood supply
- Neoplasms, Experimental/pathology
- Neovascularization, Pathologic
- Neovascularization, Physiologic
- Rats
- Rats, Sprague-Dawley
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transplantation, Heterologous
- Tumor Cells, Cultured
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
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Affiliation(s)
- Roger G Fahmy
- Centre for Vascular Research, University of New South Wales, Sydney NSW 2052, Australia
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32
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33
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Manley PW, Martiny-Baron G, Schlaeppi JM, Wood JM. Therapies directed at vascular endothelial growth factor. Expert Opin Investig Drugs 2002; 11:1715-36. [PMID: 12457433 DOI: 10.1517/13543784.11.12.1715] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The inhibition of angiogenesis through vascular endothelial growth factor (VEGF) receptor targeting is a strategy that is relatively tumour selective. The high selectivity achieved with neutralising antibodies, soluble receptors and ribozymes reduces the risk of adverse reactions not related to VEGF inhibition itself. Small-molecule, orally-active protein kinase inhibitors provide an attractive alternative for chronic therapy, although specifically targeting a small subset of protein kinases from the approximately 550 expressed in mammalian cells is a challenge. Current efforts have resulted in promising clinical data for several synthetic VEGF receptor kinase inhibitors, of which PTK787/ZK222584 and ZD6474 are proceeding into large size clinical trials. It seems likely that blockers of the VEGF signalling pathway will be unsuitable for monotherapy, and that their role will be as an adjunct to additional antiangiogenic agents together with directly-acting antitumour agents or radiation therapy. Caution is needed with combinations of anti-VEGF therapies and cytotoxic agents, as coadministration of cytotoxic agents with either the kinase inhibitor SU5416 or the VEGF antibody avastin appears to be associated with bleeding and thrombotic adverse events.
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34
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Sepp-Lorenzino L, Thomas KA. Antiangiogenic agents targeting vascular endothelial growth factor and its receptors in clinical development. Expert Opin Investig Drugs 2002; 11:1447-65. [PMID: 12387705 DOI: 10.1517/13543784.11.10.1447] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
There is ample therapeutic opportunity for the use of antiangiogenic inhibitors in the clinic, as there are several human diseases that are dependent upon angiogenesis [1]. However, no disease has attracted as much attention as a target for antiangiogenic therapy as malignant disorders. There is a vast amount of literature acting as proof-of-principle for the use of angiogenic inhibitors as effective agents for blocking tumour-induced angiogenesis and subverting tumour growth and disease dissemination. One of the unique attractions of targeting tumour angiogenesis is that vascular endothelial cells are a genetically stable population in which acquisition of therapeutic resistance might be less efficient than in genetically unstable tumour cells [2,3]. This review covers inhibitors that target the tumour angiogenic agent vascular endothelial growth factor and its receptors as one such antiangiogenic approach. Many agents in this class are in clinical trials with limited reports of toxicity and some early evidence of clinical benefit.
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Affiliation(s)
- Laura Sepp-Lorenzino
- Department of Cancer Research, Merck Research Laboratories, WP26-462, West Point, PA 19486, USA.
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35
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Abstract
This review describes some of the contributions of chemistry to the RNA field with a personal bias towards the phosphorothioate modification and the derivatives at the ribose 2'-position. The usefulness of these modifications is discussed and documented with some examples.
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Affiliation(s)
- F Eckstein
- Max-Planck-Institut für experimentelle Medizin, Hermann-Rein-Str. 3, 37075 Göttingen, Germany.
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36
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Jackson JK, Liang LS, Hunter WL, Reynolds M, Sandberg JA, Springate C, Burt HM. The encapsulation of ribozymes in biodegradable polymeric matrices. Int J Pharm 2002; 243:43-55. [PMID: 12176294 DOI: 10.1016/s0378-5173(02)00228-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ribozymes are catalytic RNA that bind and cleave specific regions of target RNA. Therefore, protein synthesis by the target RNA may be specifically inhibited by ribozymes. However, ribozymes are rapidly cleared from plasma so effective treatment of proliferative diseases may rely on the repeated administration of these agents to maintain therapeutic ribozyme concentrations. Therefore, the objective of this study was to encapsulate ribozymes in injectable polymeric paste and microsphere formulations to allow for the controlled release of these agents over extended periods of time. Ribozymes were effectively encapsulated in poly(L-lactic acid) (PLLA) and poly(lactic-co-glycolic) (PLGA) microspheres in various size ranges using a modified water-in-oil-in-water emulsion system and in poly(epsilon-caprolactone) (PCL) pastes by physical blending. These formulations released non-degraded ribozymes, in vitro, in a controlled manner. PLLA microspheres released the ribozymes rapidly whereas PLGA released drugs more slowly. The release rate of ribozymes from PCL pastes could be effectively controlled by altering the loading concentration of ribozymes in the paste. These polymeric injectable formulations of ribozymes may allow for the extended treatment of localized disease sites, such as cancer and arthritis, without the need for repeated dosing.
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Affiliation(s)
- John K Jackson
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, 2146 East Mall, BC, Canada V6T 1Z3
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37
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Radka SF, Pasko C, Haeberli P, Beigelman L. The development of a monoclonal antibody specific for a 2(')-C-allyl modification of uridine, and its use in the localization of ribozymes in vivo. Anal Biochem 2002; 307:40-6. [PMID: 12137777 DOI: 10.1016/s0003-2697(02)00017-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ribozymes are catalytically active RNA molecules that cleave other RNA molecules in a sequence-specific fashion, with significant turnover. The successful design and synthesis of ribozymes with modifications to increase their stability in biological fluids, while maintaining catalytic activity, has been instrumental in moving this technology from the laboratory into clinical trials. With the entry of ribozymes into the clinical setting, the need has arisen for reagents and/or assays to detect these drugs in tissues. We have developed a monoclonal antibody to the 2(')-deoxy-2(')-C-allyl uridine modification present in our synthetic hammerhead ribozymes. The monoclonal antibody, termed CA1USR, is a murine IgG1(k), whose epitope appears to involve both the 2(')-C-allyl modification, and the uridine base. Use of CA1USR for immunohistochemical detection of ribozymes in the tissues of mice which were administered two structurally different ribozymes has demonstrated its utility as a reagent for in vivo localization of ribozymes containing the 2(')-C-allyl uridine modification.
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Affiliation(s)
- Susan F Radka
- Ribozyme Pharmaceuticals, Inc., Boulder, CO 80301, USA.
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38
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Abstract
Expensive failures in the pharmaceutical industry might be avoided by target validation at an early stage. Often, the full consequences of inhibiting a chosen drug target do not emerge until late in the development process. One option is to use hammerhead ribozymes as highly specific ribonucleases targeted exclusively at the mRNA encoding the target protein. The first part of this review is concerned with the mechanism and design of hammerhead ribozymes. This includes the chemistry of their action, specificity of cleavage and ability to discriminate between different mRNAs and selection of suitable cleavage sites. In considering their use for target validation, hammerhead ribozymes are divided into two categories. Endogenous ribozymes are transcribed inside the cell where they act whilst exogenous are introduced into the cell from outside. Exogenous ribozymes are synthesised chemically and must be protected against cellular nucleases. Information is provided on transfection methods and vectors that have been used with endogenous ribozymes as well as synthesis and chemical modification of exogenous ribozymes. Of proteins inhibited in cells or whole organisms, those in animal experiments are emphasised. Comparisons are made with other approaches, especially the use of antisense oligonucleotides or RNA.
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Affiliation(s)
- John Goodchild
- Center for Discovery of Drugs and Diagnostics, University of Central Florida, 12722 Research Parkway, Orlando, FL 32826, USA.
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39
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Zinnen SP, Domenico K, Wilson M, Dickinson BA, Beaudry A, Mokler V, Daniher AT, Burgin A, Beigelman L. Selection, design, and characterization of a new potentially therapeutic ribozyme. RNA (NEW YORK, N.Y.) 2002; 8:214-28. [PMID: 11911367 PMCID: PMC1370244 DOI: 10.1017/s1355838202014723] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
An in vitro selection was designed to identify RNA-cleaving ribozymes predisposed for function as a drug. The selection scheme required the catalyst to be trans-acting with phosphodiesterase activity targeting a fragment of the Kras mRNA under simulated physiological conditions. To increase stabilization against nucleases and to offer the potential for improved functionality, modified sequence space was sampled by transcribing with the following NTPs: 2'-F-ATP, 2'-F-UTP, or 2'-F-5-[(N-imidazole-4-acetyl) propylamine]-UTP, 2'-NH2-CTP, and GTP. Active motifs were identified and assessed for their modified NMP and divalent metal dependence. The minimization of the ribozyme's size and the ability to substitute 2'-OMe for 2'-F and 2'-NH2 moieties yielded the motif from these selections most suited for both nuclease stability and therapeutic development. This motif requires only two 2'-NH2-Cs and functions as a 36-mer. Its substrate sequence requirements were determined to be 5'-Y-G-H-3'. Its half-life in human serum is >100 h. In physiologically relevant magnesium concentrations [approximately 1 mM] its kcat = 0.07 min(-1), Km = 70 nM. This report presents a novel nuclease stable ribozyme, designated Zinzyme, possessing optimal activity in simulated physiological conditions and ready for testing in a therapeutic setting.
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Affiliation(s)
- Shawn P Zinnen
- Ribozyme Pharmaceuticals Incorporated, Boulder, Colorado 80301, USA.
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40
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Abstract
Vascular endothelial growth factor (VEGF) is the term used for a family of tumor-derived angiogenic factors that mediate endothelial proliferation and vascular permeability. Preclinical models have demonstrated the essential nature of VEGF in the angiogenesis of solid tumor growth and metastasis, whereas pathologic investigations have revealed strong correlations between VEGF production, microvessel density, and overall aggressiveness of many human solid tumors. Recent advances in the understanding of the molecular mechanisms of VEGF action have led to successful models for intervention in VEGF-mediated pathways in therapy for solid tumors. These include antibodies to block the binding of VEGF to its cellular receptors, small-molecule chemical inhibitors of the tyrosine kinase functions of the VEGF receptors, and antisense nucleic acids to interfere with cellular production of VEGF. Clinical investigations are ongoing to test the value of VEGF-based intervention alone or in combination with other anticancer agents.
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Affiliation(s)
- Kim Margolin
- Departments of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, 1500 East Duarte Road, Duarte, CA 91010, USA.
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41
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Yang S, Xin X, Zlot C, Ingle G, Fuh G, Li B, Moffat B, de Vos AM, Gerritsen ME. Vascular endothelial cell growth factor-driven endothelial tube formation is mediated by vascular endothelial cell growth factor receptor-2, a kinase insert domain-containing receptor. Arterioscler Thromb Vasc Biol 2001; 21:1934-40. [PMID: 11742867 DOI: 10.1161/hq1201.099432] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Vascular endothelial cell growth factor (VEGF) binds to 2 related receptor tyrosine kinases, known as kinase insert domain-containing receptor (KDR) and fms-like tyrosine kinase (Flt-1). The KDR has been shown to mediate VEGF-stimulated endothelial cell mitogenesis, migration, and permeability. The Flt-1 receptor has been suggested to mediate VEGF-stimulated endothelial branching morphogenesis, a process whereby endothelial cells, in the presence of a 3D milieu composed of extracellular matrix components and a mixture of growth factors, undergo a morphological transition into a tubular network with many lumina. In the present study, we have used 2 independent endothelial cell tube formation models and highly selective VEGF mutants for the KDR and Flt-1 receptors. We demonstrate that KDR, not Flt-1, stimulation is responsible for the induction of endothelial tubulogenesis. In addition, we demonstrate a modulatory role for Flt-1 in VEGF-mediated tube formation. We also report that VEGF-driven endothelial tube formation is inhibited by selective inhibitors of mitogen-activated protein kinase activation and p38 protein kinase.
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Affiliation(s)
- S Yang
- Department of Cardiovascular Research, Genentech, Inc, South San Francisco, CA 94080, USA
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42
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Stefanik DF, Fellows WK, Rizkalla LR, Rizkalla WM, Stefanik PP, Deleo AB, Welch WC. Monoclonal antibodies to vascular endothelial growth factor (VEGF) and the VEGF receptor, FLT-1, inhibit the growth of C6 glioma in a mouse xenograft. J Neurooncol 2001; 55:91-100. [PMID: 11817706 DOI: 10.1023/a:1013329832067] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Monoclonal antibodies raised to peptide sequences of vascular endothelial growth factor (VEGF) and the VEGF receptor, FLT-1, inhibited the growth of C6 tumors growing subcutaneously in nude mice. Immunohistochemical analysis demonstrated antibody targeting of blood vessels, tumor cells, and macrophages. A control antibody demonstrated no growth inhibition or tumor uptake. An antibody to FLT- I impaired microvascular maturation and diminished the accumulation of tumor infiltrating macrophages. The antibodies demonstrated affinity for microvasculature and tumor cells in immunohistochemistry of human glioblastoma multiforme. Targeting VEGF and its receptors has potential in the treatment of tumors of the central nervous system. FLT-1 presents an attractive target due to its presence on multiple cell types.
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Affiliation(s)
- D F Stefanik
- Department of Radiation Oncology, Conemaugh Memorial Medical Center, Johnstown, PA, USA.
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43
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Abstract
Angiogenesis - the formation of new blood vessels within a tumor (or many other tissue types) - has become a hotbed of pharmacological research as well as industrial drug discovery. This is the result of the efforts of a generation of scientists elucidating the complex (patho)physiological, biochemical and molecular events accompanying angiogenesis. It is estimated that >300 drug candidates are currently in various stages of testing, and it is, therefore, impossible to capture all of this in a brief review. Therefore, the emphasis here is on relatively advanced projects that are either in preclinical or clinical development, thus neglecting, to a large extent, the many exciting avenues being pursued in both academic and biotechnology laboratories. Although the potential of the approaches described cannot be overestimated, it is also important to note that there is still no drug on the market that achieves clinical benefit based on a selective modulation or inhibition of angiogenesis.
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Affiliation(s)
- A Matter
- Head of Oncology Research, Novartis Pharma AG, 4002, Tel.: +41 61 696 2049; fax: +41 61 696 7826, Basel, Switzerland
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44
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Abstract
The majority of cancer have an absolute requirement for angiogenesis, the process by which new blood vessels are formed. The most potent angiogenic cytokine is vascular endothelial growth factor (VEGF) and there has been substantial research into the development of VEGF/VEGF receptor (VEGFR) antagonists. To date these strategies have included gene therapy techniques that deliver antisense oligonucleotides, soluble VEGFRs that function in a dominant negative fashion and ribozymes. Additional strategies have included the development of receptor tyrosine kinase (RTK) inhibitors and monoclonal antibodies (mAbs) directed against VEGF or the signalling receptor. The most promising agents appear to be the monoclonal anti-VEGF antibodies and the RTK inhibitors as these have demonstrated broad spectrum antitumour activity in vivo and single agent activity in early phase clinical trials in patients with advanced pre-treated breast and colorectal carcinoma and Kaposi's sarcoma. The RTK inhibitors are of particular interest as they can be administered by mouth. Collation of the early clinical trial data suggests that VEGF antagonists are largely well-tolerated but may be associated with vascular toxicities such as haemorrhage and thromboembolic events. Combination studies of chemotherapy and VEGF antagonists are underway but the benefit of these regimens will need to be established in adequately powered Phase III studies. Potentially these agents may play a role in the treatment of both early (adjuvant) and advanced cancer. The efficacy of the drugs will be explored in a number of non-malignant conditions including rheumatoid arthritis (RA), psoriasis, diabetic retinopathy and possibly as non-steroidal contraceptives but the overall clinical development of these agents can only be optimised if appropriate biological end points are identified and incorporated into clinical trials.
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Affiliation(s)
- J Hasan
- Department of Medical Oncology, Cancer Research Campaign Dept. Medical Oncology, Christie Hospital, Wilmslow Road, Withington, Manchester M20 4BX, UK
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45
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Abstract
The hammerhead ribozyme is an intriguing RNA molecule with the ability to serve as a catalyst to cleave sequence-specifically RNA molecules in an intermolecular reaction. Preferentially Mg(2+) is required for optimal activity by inducing the catalytically competent conformation and by possibly acting as an acid-base catalyst. Even though the three-dimensional structure has been elucidated details of the structure-function relationship and of the mechanism remain unanswered. The hammerhead ribozyme has stimulated the concept of the sequence-specific cleavage of mRNAs intracellularly and thus to inhibit gene expression by preventing translation. This represents an area of considerable interest as it has the potential for the development of drugs.
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Affiliation(s)
- F Eckstein
- Max-Planck Institut für experimentelle Medizin, Hermann-Rein-Str. 3, D-37075 Göttingen, Germany.
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46
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Neufeld G, Kessler O, Vadasz Z, Gluzman-Poltorak Z. The Contribution of Proangiogenic Factors to the Progression of Malignant Disease. Surg Oncol Clin N Am 2001. [DOI: 10.1016/s1055-3207(18)30069-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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47
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Abstract
Several inhibitors of angiogenesis are being developed for the treatment of cancer. One dominant strategy involves disruption of the vascular endothelial growth factor (VEGF) pathway by inhibition of the receptors for VEGF. Inhibition of the VEGF receptor activity can be accomplished using catalytic RNA molecules known as ribozymes, which downregulate VEGF receptor function by specifically cleaving the mRNAs for the primary VEGF receptors, Flt-1 and KDR. Significant inhibition of angiogenesis using ribozymes against both receptors has been demonstrated. In animal tumor models, antitumor effects are most pronounced with the anti-Flt-1 ribozyme known as Angiozyme (Ribozyme Pharmaceuticals, Boulder, CO). Extensive preclinical studies have demonstrated no significant toxicities. Clinical trials of Angiozyme are currently in progress for patients with advanced malignancy. Preliminary results demonstrate Angiozyme to be well tolerated, without significant side effects. Several phase II trials are underway for patients with advanced malignancy to test therapeutic efficacy.
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Affiliation(s)
- D E Weng
- Department of Hematology and Oncology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, T-40, Cleveland, OH 44195, USA.
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48
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Abstract
Angiogenesis is the outgrowth of new vessels from pre-existing ones. Tumour growth and metastasis is dependent on angiogenesis and many stimulatory and inhibitory factors have been described which play an active role in this process. Inhibition of tumour neovasculature may be one strategy to inhibit tumour growth. Naturally occurring inhibitors of angiogenesis have been discovered and synthetic agents have been designed. Many of these inhibitors are currently being evaluated in clinical trials for the treatment of cancer. This review discusses the mechanism of action of these anti-angiogenics as well as a description of the clinical trials in which they are being evaluated.
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Affiliation(s)
- T G Zogakis
- Surgery Branch, National Cancer Institute, 10/2B1710 Center Drive, Bethesda, MD 20892, USA
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49
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Sandberg JA, Parker VP, Blanchard KS, Sweedler D, Powell JA, Kachensky A, Bellon L, Usman N, Rossing T, Borden E, Blatt LM. Pharmacokinetics and Tolerability of an Antiangiogenic Ribozyme (ANGIOZYME™) in Healthy Volunteers. J Clin Pharmacol 2000. [DOI: 10.1177/009127000004001217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Nassim Usman
- Ribozyme Pharmaceuticals, Inc., Boulder, Colorado
| | | | - Ernest Borden
- Cleveland Clinic Foundation, Taussig Cancer Center/Experimental Therapeutics, Cleveland, Ohio
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50
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Usman N, Blatt LM. Nuclease-resistant synthetic ribozymes: developing a new class of therapeutics. J Clin Invest 2000; 106:1197-202. [PMID: 11086019 PMCID: PMC381444 DOI: 10.1172/jci11631] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- N Usman
- Research and Development, Ribozyme Pharmaceuticals Inc., Boulder, Colorado 80301, USA.
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