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Ma J, Waxman DJ. Modulation of the antitumor activity of metronomic cyclophosphamide by the angiogenesis inhibitor axitinib. Mol Cancer Ther 2008; 7:79-89. [PMID: 18202011 DOI: 10.1158/1535-7163.mct-07-0584] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The promising but still limited efficacy of angiogenesis inhibitors as monotherapies for cancer treatment indicates a need to integrate these agents into existing therapeutic regimens. Presently, we investigate the antitumor activity of the small-molecule angiogenesis inhibitor axitinib (AG-013736) and its potential for combination with metronomic cyclophosphamide. Axitinib significantly inhibited angiogenesis in rat 9L tumors grown s.c. in scid mice but only moderately delayed tumor growth. Combination of axitinib with metronomic cyclophosphamide fully blocked 9L tumor growth on initiation of drug treatment. In contrast, metronomic cyclophosphamide alone required multiple treatment cycles to halt tumor growth. However, in contrast to the substantial tumor regression that is ultimately induced by metronomic cyclophosphamide, the axitinib/cyclophosphamide combination was tumor growth static. Axitinib did not inhibit hepatic activation of cyclophosphamide or export of its activated metabolite, 4-hydroxy-cyclophosphamide (4-OH-CPA), to extrahepatic tissues; rather, axitinib selectively decreased 9L tumor uptake of 4-OH-CPA by 30% to 40%. The reduced tumor penetration of 4-OH-CPA was associated with a decrease in cyclophosphamide-induced tumor cell apoptosis and a block in the induction of the endogenous angiogenesis inhibitor thrombospondin-1 in tumor-associated host cells, which may contribute to the absence of tumor regression with the axitinib/cyclophosphamide combination. Finally, axitinib transiently increased 9L tumor cell apoptosis, indicating that its effects are not limited to the endothelial cell population. These findings highlight the multiple effects that may characterize antiangiogenic agent/metronomic chemotherapy combinations and suggest that careful optimization of drug scheduling and dosages will be required to maximize antitumor responses.
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Affiliation(s)
- Jie Ma
- Division of Cell and Molecular Biology, Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA
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102
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Timke C, Zieher H, Roth A, Hauser K, Lipson KE, Weber KJ, Debus J, Abdollahi A, Huber PE. Combination of Vascular Endothelial Growth Factor Receptor/Platelet-Derived Growth Factor Receptor Inhibition Markedly Improves Radiation Tumor Therapy. Clin Cancer Res 2008; 14:2210-9. [DOI: 10.1158/1078-0432.ccr-07-1893] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Purpose: Investigations on the combination of radiotherapy with vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) antiangiogenic agents, which has the potential to improve the clinical outcome in cancer patients.
Experimental Design: Here, we analyze the combined VEGF (SU5416) and PDGF (SU6668) receptor tyrosine kinase inhibition with irradiation in human endothelium (HUVEC), prostate cancer (PC3), and glioblastoma (U87) in vitro and in vivo.
Results: Combined inhibition of VEGF and PDGF signaling resulted in enhanced apoptosis, reduced cell proliferation, and clonogenic survival as well as reduced endothelial cell migration and tube formation compared with single pathway inhibition. These effects were further enhanced by additional irradiation. Likewise, in PC3 and U87 tumors growing s.c. on BALB/c nu/nu mice, dual inhibition of VEGF and PDGF signaling significantly increased tumor growth delay versus each monotherapy. Interestingly, radiation at ∼20% of the dose necessary to induce local tumor control exerts similar tumor growth-inhibitory effects as the antiangiogenic drugs given at their maximum effective dose. Addition of radiotherapy to both mono- as well as dual-antiangiogenic treatment markedly increased tumor growth delay. With respect to tumor angiogenesis, radiation further decreased microvessel density (CD31 count) and tumor cell proliferation (Ki-67 index) in all drug-treated groups. Of note, the slowly growing PC3 tumor responded better to the antiangiogenic drug treatments than the faster-growing U87 tumor. In addition to the beneficial effect of abrogating VEGF survival signaling when combined with radiation, we identified here a novel mechanism for the tumor escape from radiation damage. We found that radiation induced up-regulation of all four isoforms of PDGF (A-D) in endothelial cells supporting adjacent smooth muscle cells resulting in a prosurvival effect of radiation. The addition of SU6668 attenuated this undesirable paracrine radiation effect, which may rationalize the combined application of radiation with PDGF signaling inhibition to increase antitumor effects.
Conclusion: A relative low radiation dose markedly enhances local antitumor effects of combined VEGF and PDGF signaling inhibition, suggesting a promising combination regimen for local tumor treatment with radiotherapy remaining an essential element.
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Affiliation(s)
- Carmen Timke
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
| | - Heike Zieher
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
| | - Alexandra Roth
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
| | - Kai Hauser
- 4Institucio Catalana de Recerca i Estudis Avancats, Barcelona, Spain; and
- 5Department of Mathematics, University of California, Berkeley, California
| | - Kenneth E. Lipson
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
| | - Klaus J. Weber
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
| | - Jürgen Debus
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
| | - Amir Abdollahi
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
- 3Center of Cancer Systems Biology, Department of Medicine, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts
| | - Peter E. Huber
- 1Department of Radiation Oncology, German Cancer Research Center
- 2Department of Radiation Oncology, University of Heidelberg Medical School, Heidelberg, Germany
- 3Center of Cancer Systems Biology, Department of Medicine, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, Massachusetts
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103
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Milker-Zabel S, Zabel-du Bois A, Ranai G, Trinh T, Unterberg A, Debus J, Lipson KE, Abdollahi A, Huber PE. SU11657 enhances radiosensitivity of human meningioma cells. Int J Radiat Oncol Biol Phys 2008; 70:1213-8. [PMID: 18234428 DOI: 10.1016/j.ijrobp.2007.11.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 10/31/2007] [Accepted: 11/16/2007] [Indexed: 10/22/2022]
Abstract
PURPOSE To analyze the effect of the multireceptor tyrosine kinase inhibitor SU11657 (primarily vascular endothelial growth factor, platelet-derived growth factor) in combination with irradiation in freshly isolated primary human meningioma cells. METHODS AND MATERIALS Tumor specimens were obtained from meningioma patients undergoing surgery at the Department of Neurosurgery, University of Heidelberg, Germany. For the present study only cells up to passage 6 were used. Benign and atypical meningioma cells and human umbilical vein endothelial cells (HUVEC) were treated with SU11657 alone and in combination with 6-MV photons (0-10 Gy). Clonogenic survival and cell proliferation were determined alone and in coculture assays to determine direct and paracrine effects. RESULTS Radiation and SU11657 alone reduced cell proliferation in atypical and benign meningioma cells as well as in HUVEC in a dose-dependent manner. SU11657 alone also reduced clonogenic survival of benign and atypical meningioma cells. SU11657 increased radiosensitivity of human meningioma cells in clonogenic survival and cell number/proliferation assays. The anticlonogenic and antiproliferative effects alone and the radiosensitization effects of SU11657 were more pronounced in atypical meningioma cells compared with benign meningioma cells. CONCLUSION Small-molecule tyrosine kinase inhibitors like SU11657 are capable of amplifying the growth inhibitory effects of irradiation in meningioma cells. These data provide a rationale for further clinical evaluation of this combination concept, especially in atypical and malignant meningioma patients.
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104
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Fenton BM, Paoni SF. The addition of AG-013736 to fractionated radiation improves tumor response without functionally normalizing the tumor vasculature. Cancer Res 2007; 67:9921-8. [PMID: 17942924 DOI: 10.1158/0008-5472.can-07-1066] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although antiangiogenic strategies have proven highly promising in preclinical studies and some recent clinical trials, generally only combinations with cytotoxic therapies have shown clinical effectiveness. An ongoing question has been whether conventional therapies are enhanced or compromised by antiangiogenic agents. The present studies were designed to determine the pathophysiologic consequences of both single and combined treatments using fractionated radiotherapy plus AG-013736, a receptor tyrosine kinase inhibitor that preferentially inhibits vascular endothelial growth factor receptors. DU145 human prostate xenograft tumors were treated with (a) vehicle alone, (b) AG-013736, (c) 5x2 Gy/wk radiotherapy fractions, or (d) the combination. Automated image processing of immunohistochemical images was used to determine total and perfused blood vessel spacing, overall hypoxia, pericyte/collagen coverage, proliferation, and apoptosis. Combination therapy produced an increased tumor response compared with either monotherapy alone. Vascular density progressively declined in concert with slightly increased alpha-smooth muscle actin-positive pericyte coverage and increased overall tumor hypoxia (compared with controls). Although functional vessel endothelial apoptosis was selectively increased, reductions in total and perfused vessels were generally proportionate, suggesting that functional vasculature was not specifically targeted by combination therapy. These results argue against either an AG-013736- or a combination treatment-induced functional normalization of the tumor vasculature. Vascular ablation was mirrored by the increased appearance of dissociated pericytes and empty type IV collagen sleeves. Despite the progressive decrease in tumor oxygenation over 3 weeks of treatment, combination therapy remained effective and tumor progression was minimal.
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Affiliation(s)
- Bruce M Fenton
- Department of Radiation Oncology, University of Rochester Medical Center, Rochester, New York 14642, USA.
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105
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O'Reilly MS. Antiangiogenesis and vascular endothelial growth factor/vascular endothelial growth factor receptor targeting as part of a combined-modality approach to the treatment of cancer. Int J Radiat Oncol Biol Phys 2007; 69:S64-6. [PMID: 17848299 PMCID: PMC2092454 DOI: 10.1016/j.ijrobp.2007.04.093] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Accepted: 04/29/2007] [Indexed: 12/31/2022]
Affiliation(s)
- Michael S O'Reilly
- Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
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106
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Shiraga E, Barichello JM, Ishida T, Kiwada H. A metronomic schedule of cyclophosphamide combined with PEGylated liposomal doxorubicin has a highly antitumor effect in an experimental pulmonary metastatic mouse model. Int J Pharm 2007; 353:65-73. [PMID: 18155369 DOI: 10.1016/j.ijpharm.2007.11.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 10/11/2007] [Accepted: 11/10/2007] [Indexed: 11/28/2022]
Abstract
Metronomic chemotherapy is a novel approach to the control of advanced cancer, as it appears to preferentially inhibit endothelial cell activity in the growing vasculature of tumors. Doxorubicin-containing sterically stabilized liposomes (DXR-SL) accumulate in large amounts in tumor tissue, resulting in enhanced antitumor effects of the encapsulated DXR. In the present study, it was hypothesized that metronomic chemotherapy may further augment the accumulation of DXR-SL, improving its therapeutic efficacy. This study tests the antitumor efficacy for the combination of a metronomic cyclophosphamide (CPA)-dosing schedule with sequential intravenous injections of DXR-SL in the treatment of lung metastatic B16BL6 melanoma-bearing mice. Three dosing schedules for the combination of metronomic CPA injections (s.c. 170 mg/kg every 6 days) plus either a low or a high dose of DXR-SL (i.v. 1 or 5 mg/kg every 6 days) were set: Schedule I, DXR-SL was given 3 days before the first CPA treatment; Schedule II, DXR-SL and CPA were given simultaneously; and, Schedule III, DXR-SL was given 3 days after the first CPA treatment. Lung weight and median survival time (MST) were evaluated. As expected, both the dosing schedule as well as the dose of DXR-SL improved therapeutic efficacy. Schedule I with the low DXR dose and Schedule II with the low or high DXR dose significantly increased MST, compared with regular metronomic CPA therapy. Under the dosing schedules (Schedule I with the low DXR dose and Schedule II with the high DXR), there was a strong relationship between increased MST and decreased lung weight. However, Schedule I with high DXR dose resulted in significantly lower lung weights, but did not increase MST, suggesting that chemotherapy may result in increased toxicity in some conditions. Although treatment regimens require optimization, the results of the present study may prove useful in further explorations of combining metronomic chemotherapy with liposomal anticancer drugs in the treatment of solid tumors.
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Affiliation(s)
- Emi Shiraga
- Department of Pharmacokinetics and Biopharmaceutics, Subdivision of Biopharmaceutical Science, Institute of Health Biosciences, The University of Tokushima, Tokushima, Japan
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107
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Ansiaux R, Baudelet C, Jordan BF, Crokart N, Martinive P, DeWever J, Grégoire V, Feron O, Gallez B. Mechanism of reoxygenation after antiangiogenic therapy using SU5416 and its importance for guiding combined antitumor therapy. Cancer Res 2007; 66:9698-704. [PMID: 17018628 DOI: 10.1158/0008-5472.can-06-1854] [Citation(s) in RCA: 51] [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
Emerging preclinical studies support the concept of a transient "normalization" of tumor vasculature during the early stage of antiangiogenic treatment, with possible beneficial effects on associated radiotherapy or chemotherapy. One key issue in this area of research is to determine whether this feature is common to all antiangiogenic drugs and whether the phenomenon occurs in all types of tumors. In the present study, we characterized the evolution of the tumor oxygenation (in transplantable liver tumor and FSAII tumor models) after administration of SU5416, an antagonist of the vascular endothelial growth factor receptor. SU5416 induced an early increase in tumor oxygenation [measured by electronic paramagnetic resonance (EPR)], which did not correlate with remodeling of the tumor vasculature (assessed by CD31 labeling using immunohistochemistry) or with tumor perfusion (measured by dynamic contrast enhanced-magnetic resonance imaging). Inhibition of mitochondrial respiration (measured by EPR) was responsible for this early reoxygenation. Consistent with these unique findings in the tumor microenvironment, we found that SU5416 potentiated tumor response to radiotherapy but not to chemotherapy. In addition to the fact that the characterization of the tumor oxygenation is essential to enable correct application of combined therapies, our results show that the long-term inhibition of oxygen consumption is a potential novel target in this class of compounds.
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Affiliation(s)
- Réginald Ansiaux
- Laboratory of Biomedical Magnetic Resonance, Université Catholique de Louvain, Brussels, Belgium
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108
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Le Tourneau C, Faivre S, Raymond E. New developments in multitargeted therapy for patients with solid tumours. Cancer Treat Rev 2007; 34:37-48. [PMID: 17983706 DOI: 10.1016/j.ctrv.2007.09.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 09/13/2007] [Indexed: 11/16/2022]
Abstract
Molecularly targeted anticancer therapies are now available that have been rationally designed to interact with specific proteins associated with tumour development or progression. The main purpose of this article is to review the rationale and phase II/III clinical data for approved and emerging multitargeted agents used in the treatment of solid tumours. Imatinib, sunitinib, sorafenib, and dasatinib have all produced advances in the treatment of the indications for which they are licensed and show promising activity in other tumour types. Newer multitargeted agents in development appear, from preliminary phase I and II data, to be active in a broad range of tumour types, although the clinical relevance of this activity is as yet unproven. The challenge for the future is to ensure that the potential of multitargeted agents is maximised by selecting the patient populations most likely to derive clinical benefit, by optimising the dose schedules used, and by investigating multitargeted therapies combined with other agents of the same type or with conventional chemotherapy and/or other treatment modalities.
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Affiliation(s)
- C Le Tourneau
- Service Inter-Hospitalier de Cancérologie Beaujon-Bichat, Hôpital Beaujon, 100, Boulevard du Général Leclerc, Clichy, France.
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109
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Gerhardt H, Semb H. Pericytes: gatekeepers in tumour cell metastasis? J Mol Med (Berl) 2007; 86:135-44. [PMID: 17891366 DOI: 10.1007/s00109-007-0258-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 07/23/2007] [Accepted: 08/17/2007] [Indexed: 02/08/2023]
Abstract
Tumour cells use two major routes to spread during metastasis, e.g. lymph vessels and blood vessels within or surrounding the primary tumour. The growth rate of the primary tumour often correlates with the quantity of new blood vessels that form within the tumour. However, qualitative abnormalities of the tumour vasculature profoundly affect the perfusion of the primary tumour and the escape of tumour cells into the circulation. In this paper, we review recent evidence for a novel role of the supporting mural cells in limiting blood-borne metastasis.
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Affiliation(s)
- Holger Gerhardt
- Vascular Biology Laboratory, London Research Institute-Cancer Research UK, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK.
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110
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Dickson PV, Hamner JB, Sims TL, Fraga CH, Ng CYC, Rajasekeran S, Hagedorn NL, McCarville MB, Stewart CF, Davidoff AM. Bevacizumab-induced transient remodeling of the vasculature in neuroblastoma xenografts results in improved delivery and efficacy of systemically administered chemotherapy. Clin Cancer Res 2007; 13:3942-50. [PMID: 17606728 DOI: 10.1158/1078-0432.ccr-07-0278] [Citation(s) in RCA: 333] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Dysfunctional tumor vessels can be a significant barrier to effective cancer therapy. However, increasing evidence suggests that vascular endothelial growth factor (VEGF) inhibition can effect transient "normalization" of the tumor vasculature, thereby improving tumor perfusion and, consequently, delivery of systemic chemotherapy. We sought to examine temporal changes in tumor vascular function in response to the anti-VEGF antibody, bevacizumab. EXPERIMENTAL DESIGN Established orthotopic neuroblastoma xenografts treated with bevacizumab were evaluated at serial time points for treatment-associated changes in intratumoral vascular physiology, penetration of systemically administered chemotherapy, and efficacy of combination therapy. RESULTS After a single bevacizumab dose, a progressive decrease in tumor microvessel density to <30% of control was observed within 7 days. Assessment of the tumor microenvironment revealed a rapid, sustained decrease in both tumor vessel permeability and tumor interstitial fluid pressure, whereas intratumoral perfusion, as assessed by contrast-enhanced ultrasonography, was improved, although this latter change abated by 1 week. Intratumoral drug delivery mirrored these changes; penetration of chemotherapy was improved by as much as 81% when given 1 to 3 days after bevacizumab, compared with when both drugs were given concomitantly, or 7 days apart. Finally, administering topotecan to tumor-bearing mice 3 days after bevacizumab resulted in greater tumor growth inhibition (36% of control size) than with monotherapy (88% bevacizumab, 54% topotecan) or concomitant administration of the two drugs (44%). CONCLUSIONS Bevacizumab-mediated VEGF blockade effects alterations in tumor vessel physiology that allow improved delivery and efficacy of chemotherapy, although careful consideration of drug scheduling is required to optimize antitumor activity.
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Affiliation(s)
- Paxton V Dickson
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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111
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Burd R, Wachsberger P. Application of radiotherapy and chemotherapy protocols to pre-clinical tumor models. ACTA ACUST UNITED AC 2007; Chapter 14:Unit 14.7. [PMID: 21948166 DOI: 10.1002/0471141755.ph1407s38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This unit (1) provides background into understanding how agents that target specific molecules or receptors (molecular-targeted agents), in particular, agents affecting the tumor vasculature (perivasculature network in tumors), interact with and modify radiation therapy; (2) details factors affecting interpretation of results in murine tumor model experiments utilizing radiation therapy and drug combinations; and (3) provides specific protocols for the application of radiation therapy, both alone and in combination with chemotherapy and/or molecular-targeted agents.
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Affiliation(s)
- Randy Burd
- University of Arizona, Tucson, Arizona, USA
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112
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Igarashi K, Sakimoto I, Kataoka K, Ohta K, Miura M. Radiation-induced senescence-like phenotype in proliferating and plateau-phase vascular endothelial cells. Exp Cell Res 2007; 313:3326-36. [PMID: 17662979 DOI: 10.1016/j.yexcr.2007.06.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 05/18/2007] [Accepted: 06/06/2007] [Indexed: 11/30/2022]
Abstract
The effects of ionizing radiation (IR) on tumor angiogenesis still remain largely unknown. In this study, we found that IR (8 Gy) induces a high-frequency (80-90%) senescence-like phenotype in vascular endothelial cells (ECs) undergoing exponential growth. This finding allowed us to characterize the IR-induced senescence-like (IRSL) phenotype by examining the gene expression profiles and in vitro angiogenic activities of these ECs. The expression levels of genes associated with cell cycle progression and DNA replication were remarkably reduced in the IRSL ECs. Additionally, the in vitro invasion and migration activities of these cells through Matrigel were significantly suppressed. We also found that confluent ECs exhibited a high-frequency IRSL phenotype when they were replated immediately after irradiation, whereas incubation in plateau-phase conditions reduced the induction of this phenotype and enhanced colony formation. The kinetics of DNA double-strand break repair, which showed a faster time course in confluent ECs than in growing ECs, may contribute to the protective mechanism associated with the IRSL phenotype. These results imply that the IRSL phenotype may be important for determining the angiogenic activity of ECs following irradiation. The present study should contribute to the understanding of the effects of IR on tumor angiogenesis.
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Affiliation(s)
- Kaori Igarashi
- Oral Radiation Oncology, Department of Oral Restitution, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
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113
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Abdollahi A, Schwager C, Kleeff J, Esposito I, Domhan S, Peschke P, Hauser K, Hahnfeldt P, Hlatky L, Debus J, Peters JM, Friess H, Folkman J, Huber PE. Transcriptional network governing the angiogenic switch in human pancreatic cancer. Proc Natl Acad Sci U S A 2007; 104:12890-5. [PMID: 17652168 PMCID: PMC1931565 DOI: 10.1073/pnas.0705505104] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A shift of the angiogenic balance to the proangiogenic state, termed the "angiogenic switch," is a hallmark of cancer progression. Here we devise a strategy for identifying genetic participants of the angiogenic switch based on inverse regulation of genes in human endothelial cells in response to key endogenous pro- and antiangiogenic proteins. This approach reveals a global network pattern for vascular homeostasis connecting known angiogenesis-related genes with previously unknown signaling components. We also demonstrate that the angiogenic switch is governed by simultaneous regulations of multiple genes organized as transcriptional circuitries. In pancreatic cancer patients, we validate the transcriptome-derived switch of the identified "angiogenic network:" The angiogenic state in chronic pancreatitis specimens is intermediate between the normal (angiogenesis off) and neoplastic (angiogenesis on) condition, suggesting that aberrant proangiogenic environment contributes to the increased cancer risk in patients with chronic pancreatitis. In knockout experiments in mice, we show that the targeted removal of a hub node (peroxisome proliferative-activated receptor delta) of the angiogenic network markedly impairs angiogenesis and tumor growth. Further, in tumor patients, we show that peroxisome proliferative-activated receptor delta expression levels are correlated with advanced pathological tumor stage, increased risk for tumor recurrence, and distant metastasis. Our results therefore also may contribute to the rational design of antiangiogenic cancer agents; whereas "narrow" targeted cancer drugs may fail to shift the robust angiogenic regulatory network toward antiangiogenesis, the network may be more vulnerable to multiple or broad-spectrum inhibitors or to the targeted removal of the identified angiogenic "hub" nodes.
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Affiliation(s)
- Amir Abdollahi
- *Department of Radiation Oncology, German Cancer Research Center (DKFZ) and University of Heidelberg Medical School, Heidelberg 69120, Germany
- To whom correspondence may be addressed. E-mail: , , or
| | - Christian Schwager
- *Department of Radiation Oncology, German Cancer Research Center (DKFZ) and University of Heidelberg Medical School, Heidelberg 69120, Germany
| | - Jörg Kleeff
- Departments of General Surgery, University of Heidelberg Medical School and European Pancreas Center, Heidelberg 69120, Germany
| | - Irene Esposito
- Institute of Pathology, University of Heidelberg Medical School, Heidelberg 69120, Germany
| | - Sophie Domhan
- *Department of Radiation Oncology, German Cancer Research Center (DKFZ) and University of Heidelberg Medical School, Heidelberg 69120, Germany
| | - Peter Peschke
- *Department of Radiation Oncology, German Cancer Research Center (DKFZ) and University of Heidelberg Medical School, Heidelberg 69120, Germany
| | - Kai Hauser
- *Department of Radiation Oncology, German Cancer Research Center (DKFZ) and University of Heidelberg Medical School, Heidelberg 69120, Germany
- Department of Mathematics, University of California, Berkeley, CA 94720-3840
| | - Philip Hahnfeldt
- Center of Cancer Systems Biology, Department of Medicine, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA 02135-2997
- **Children's Hospital Boston, Vascular Biology Program and Harvard Medical School, Department of Surgery, Karp Family Research Laboratories, Boston, MA 02115
| | - Lynn Hlatky
- Center of Cancer Systems Biology, Department of Medicine, Caritas St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA 02135-2997
| | - Jürgen Debus
- *Department of Radiation Oncology, German Cancer Research Center (DKFZ) and University of Heidelberg Medical School, Heidelberg 69120, Germany
| | - Jeffrey M. Peters
- Department of Veterinary Science and Center for Molecular Toxicology and Carcinogenesis, Pennsylvania State University, University Park, PA 16802; and
| | - Helmut Friess
- Departments of General Surgery, University of Heidelberg Medical School and European Pancreas Center, Heidelberg 69120, Germany
| | - Judah Folkman
- **Children's Hospital Boston, Vascular Biology Program and Harvard Medical School, Department of Surgery, Karp Family Research Laboratories, Boston, MA 02115
- To whom correspondence may be addressed. E-mail: , , or
| | - Peter E. Huber
- *Department of Radiation Oncology, German Cancer Research Center (DKFZ) and University of Heidelberg Medical School, Heidelberg 69120, Germany
- To whom correspondence may be addressed. E-mail: , , or
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114
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Cuneo KC, Tu T, Geng L, Fu A, Hallahan DE, Willey CD. HIV protease inhibitors enhance the efficacy of irradiation. Cancer Res 2007; 67:4886-93. [PMID: 17510418 DOI: 10.1158/0008-5472.can-06-3684] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tumor vascular endothelium is rather resistant to the cytotoxic effects of radiation. The HIV protease inhibitors (HPI) amprenavir, nelfinavir, and saquinavir have previously been shown to sensitize tumor cells to the cytotoxic effects of radiation. Additionally, this class of drug has been shown to inhibit angiogenesis and tumor cell migration. Therefore, in the current study, we wanted to determine whether HPIs could enhance the effect of radiation on endothelial function. Our study shows that HPIs, particularly nelfinavir, significantly enhance radiations effect on human umbilical vein endothelial cells (HUVEC) and tumor vascular endothelium. We show that pretreatment of HUVEC with nelfinavir results in enhanced cytotoxicity, including increased apoptosis, when combined with radiation. Moreover, using several functional assays, we show that combination treatment effectively blocks endothelial cell migration and organization. These findings were accompanied by attenuation of Akt phosphorylation, a known pathway for radioresistance. Last, in vivo analysis of tumor microvasculature destruction showed a more than additive effect for nelfinavir and radiation. This study shows that HPIs can enhance the effect of ionizing radiation on vascular endothelium. Therefore, the Food and Drug Administration-approved drug, nelfinavir, may be an effective radiosensitizer in the clinic.
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Affiliation(s)
- Kyle C Cuneo
- Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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Fukumura D, Jain. RK. Tumor microvasculature and microenvironment: targets for anti-angiogenesis and normalization. Microvasc Res 2007; 74:72-84. [PMID: 17560615 PMCID: PMC2100036 DOI: 10.1016/j.mvr.2007.05.003] [Citation(s) in RCA: 485] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 04/30/2007] [Accepted: 05/10/2007] [Indexed: 12/17/2022]
Abstract
A solid tumor forms an organ-like entity comprised of neoplastic cells and non-transformed host stromal cells embedded in an extracellular matrix. Similar to normal tissues, blood vessels nourish cells residing in tumors. However, unlike normal blood vessels, tumor vasculature has abnormal organization, structure, and function. Tumor vessels are leaky and blood flow is heterogeneous and often compromised. Vascular hyperpermeability and the lack of functional lymphatic vessels inside tumors cause elevation of interstitial fluid pressure in solid tumors. Each of these abnormalities forms a physiological barrier to the delivery of therapeutic agents to tumors. Furthermore, elevated tumor interstitial fluid pressure increases fluid flow from the tumor margin into the peri-tumor area and may facilitate peri-tumor lymphatic hyperplasia and metastasis. Abnormal microcirculation in tumors also leads to a hostile microenvironment characterized by hypoxia and acidosis, which hinder the effectiveness of anti-tumor treatments such as radiation therapy and chemotherapy. In addition, host-tumor interactions regulate expression of pro- and anti-angiogenic factors and hence contribute to their imbalance and resulting pathophysiological characteristics of the tumor. Restoration of pro- and anti-angiogenic balance in tumors may "normalize" tumor vasculature and thus improve its function. Indeed, anti-angiogenic treatments directly targeting angiogenic signaling pathways as well as indirectly modulating angiogenesis show normalization of tumor vasculature and microenvironment at least transiently in both preclinical and clinical settings. Combination of cytotoxic therapy and anti-angiogenic treatment during the vascular normalization exhibits synergistic effect.
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Affiliation(s)
- Dai Fukumura
- * To whom correspondence may be addressed: Dai Fukumura or Rakesh K. Jain, Edwin L. Steele Laboratory for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, 100 Blossom Street - Cox 7, Boston MA 02114, e-mail: or
| | - Rakesh K. Jain.
- * To whom correspondence may be addressed: Dai Fukumura or Rakesh K. Jain, Edwin L. Steele Laboratory for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, 100 Blossom Street - Cox 7, Boston MA 02114, e-mail: or
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116
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Patterson DM, Rustin GJS. Vascular damaging agents. Clin Oncol (R Coll Radiol) 2007; 19:443-56. [PMID: 17459681 DOI: 10.1016/j.clon.2007.03.014] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 02/21/2007] [Accepted: 03/22/2007] [Indexed: 12/27/2022]
Abstract
To provide a comprehensive overview on vascular targeting agents and the application of radiobiological principles in pre-clinical and clinical studies, we completed a comprehensive review of published medical studies on vascular targeting agents using Pub Med. Vascular targeting agents are now divided into vascular disrupting agents (VDAs), which target the pre-existing tumour vasculature, and angiogenesis inhibitors (AIs), which prevent the formation of new blood vessels. Modest success has been seen when VDAs and AIs are used as single agents and therefore combination therapies that can work in a complimentary and synergistic manner, targeting both the tumour cells and endothelial cells, are needed. Radiobiological principles have been used to increase our understanding of these agents, and can explain the increased efficacy of combination treatments. In particular, the alteration of the tumour microenvironment by AIs and VDAs can lead to enhanced efficacy when combined with chemotherapy or radiotherapy, with phase II/III trials showing encouraging results. The optimal use and scheduling of AIs and VDAs remains to be determined. Further understanding of the mechanisms of action of these potentially very exciting anti-neoplastic agents is urgently required.
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Affiliation(s)
- D M Patterson
- Department of Medical Oncology, Mount Vernon Cancer Centre, Rickmansworth Road, Northwood, Middlesex HA6 2RN, UK.
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117
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Jain RK, Tong RT, Munn LL. Effect of vascular normalization by antiangiogenic therapy on interstitial hypertension, peritumor edema, and lymphatic metastasis: insights from a mathematical model. Cancer Res 2007; 67:2729-35. [PMID: 17363594 PMCID: PMC3022341 DOI: 10.1158/0008-5472.can-06-4102] [Citation(s) in RCA: 423] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Preclinical and clinical evidence shows that antiangiogenic agents can decrease tumor vessel permeability and interstitial fluid pressure (IFP) in a process of vessel "normalization." The resulting normalized vasculature has more efficient perfusion, but little is known about how tumor IFP and interstitial fluid velocity (IFV) are affected by changes in transport properties of the vessels and interstitium that are associated with antiangiogenic therapy. By using a mathematical model to simulate IFP and IFV profiles in tumors, we show here that antiangiogenic therapy can decrease IFP by decreasing the tumor size, vascular hydraulic permeability, and/or the surface area per unit tissue volume of tumor vessels. Within a certain window of antiangiogenic effects, interstitial convection within the tumor can increase dramatically, whereas fluid convection out of the tumor margin decreases. This would result in increased drug convection within the tumor and decreased convection of drugs, growth factors, or metastatic cancer cells from the tumor margin into the peritumor fluid or tissue. Decreased convection of growth factors, such as vascular endothelial growth factor-C (VEGF-C), would limit peritumor hyperplasia, and decreased VEGF-A would limit angiogenesis in sentinel lymph nodes. Both of these effects would reduce the probability of lymphatic metastasis. Finally, decreased fluid convection into the peritumor tissue would decrease peritumor edema associated with brain tumors and ascites accumulation in the peritoneal or pleural cavity, a major complication with a number of malignancies.
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Affiliation(s)
- Rakesh K Jain
- E.L. Steele Lab for Tumor Biology, Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
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118
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Tyrosine kinase inhibitor SU6668 represses chondrosarcoma growth via antiangiogenesis in vivo. BMC Cancer 2007; 7:49. [PMID: 17367541 PMCID: PMC1832206 DOI: 10.1186/1471-2407-7-49] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 03/17/2007] [Indexed: 12/20/2022] Open
Abstract
Background As chondrosarcomas are resistant to chemotherapy and ionizing radiation, therapeutic options are limited. Radical surgery often cannot be performed. Therefore, additional therapies such as antiangiogenesis represent a promising strategy for overcoming limitations in chondrosarcoma therapy. There is strong experimental evidence that SU6668, an inhibitor of the angiogenic tyrosine kinases Flk-1/KDR, PDGFRbeta and FGFR1 can induce growth inhibition of various primary tumors. However, the effectiveness of SU6668 on malignant primary bone tumors such as chondrosarcomas has been rarely investigated. Therefore, the aim of this study was to investigate the effects of SU6668 on chondrosarcoma growth, angiogenesis and microcirculation in vivo. Methods In 10 male severe combined immunodeficient (SCID) mice, pieces of SW1353 chondrosarcomas were implanted into a cranial window preparation where the calvaria serves as the site for the orthotopic implantation of bone tumors. From day 7 after tumor implantation, five animals were treated with SU6668 (250 mg/kg body weight, s.c.) at intervals of 48 hours (SU6668), and five animals with the equivalent amount of the CMC-based vehicle (Control). Angiogenesis, microcirculation, and growth of SW 1353 tumors were analyzed by means of intravital microscopy. Results SU6668 induced a growth arrest of chondrosarcomas within 7 days after the initiation of the treatment. Compared to Controls, SU6668 decreased functional vessel density and tumor size, respectively, by 37% and 53% on day 28 after tumor implantation. The time course of the experiments demonstrated that the impact on angiogenesis preceded the anti-tumor effect. Histological and immunohistochemical results confirmed the intravital microscopy findings. Conclusion SU6668 is a potent inhibitor of chondrosarcoma tumor growth in vivo. This effect appears to be induced by the antiangiogenic effects of SU6668, which are mediated by the inhibition of the key angiogenic receptor tyrosine kinases Flk-1/KDR, PDGFRbeta and FGFR1. The experimental data obtained provide rationale to further develop the strategy of the use of the angiogenesis inhibitor SU6668 in the treatment of chondrosarcomas in addition to established therapies such as surgery.
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Bahramsoltani M, Plendl J. Different ways to antiangiogenesis by angiostatin and suramin, and quantitation of angiostatin-induced antiangiogenesis. APMIS 2007; 115:30-46. [PMID: 17223849 DOI: 10.1111/j.1600-0463.2007.apm_405.x] [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: 12/23/2022]
Abstract
Angiogenesis, i.e. sprouting of new vessels, their remodelling and regression, is a prerequisite for growth and differentiation of organs and tissues. It is involved in many pathological processes, particularly growth and metastasis of tumours. Angiostatic therapy is a promising new strategy in the treatment of cancer. Angiogenesis inhibitors could intervene in the different phases of the angiogenic cascade, i.e. migration, proliferation, differentiation and three-dimensional organisation of endothelial cells, to inhibit the generation of tumour vessels. The aim of this study was to explore whether in a previously validated in vitro model for quantitation of angiogenesis the effects of the angiostatic factors angiostatin and suramin can be investigated and quantified. Examination of angiostatin and suramin showed that angiostatin-induced antiangiogenesis resulted in inverse angiogenesis. The addition of suramin initially resulted in increased angiogenesis. However, long-term incubation ultimately led to disintegration of endothelial structures, thus establishing the angiostatic effects of suramin. Antiangiogenesis was not only quantified using the previously validated method. It also lent itself to assessment of the extent of antiangiogenesis within the various phases of the angiogenic cascade. This method may therefore be employed in trial studies of potential angiostatic substances and related cellular mechanisms.
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Quarles CC, Schmainda KM. Assessment of the morphological and functional effects of the anti-angiogenic agent SU11657 on 9L gliosarcoma vasculature using dynamic susceptibility contrast MRI. Magn Reson Med 2007; 57:680-7. [PMID: 17390352 DOI: 10.1002/mrm.21193] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
To investigate the influence of anti-angiogenic agents on tumor perfusion, we employed a dynamic susceptibility contrast (DSC)-MRI method that utilizes a simultaneous gradient-echo (GE) and spin-echo (SE) imaging sequence to derive perfusion parameters (blood flow, blood volume, and mean transit time (MTT)). These parameters are sensitive to both the total vasculature (from the GE data) and the microvasculature (from the SE data), and can also provide a measure of the mean vessel diameter (mVD). This approach was used to evaluate the response of a 9L rat brain tumor model to 20 mg/kg and 40 mg/kg of the anti-angiogenic agent SU11657. The 20-mg/kg dose significantly decreased mVD by 29.9% (P = 0.02). The 40-mg/kg dose significantly decreased mVD by 30.4% (P = 0.0007), SE blood volume by 31.8% (P = 0.03), GE and SE MTT by 46.9% (P = 0.03) and 62.0% (P = 0.0005), and increased GE and SE blood flow by 36.6% (P = 0.04) and 52.6% (P = 0.02). These findings demonstrate that DSC-MRI perfusion methods can play a key role in the noninvasive evaluation of morphological and functional changes in tumor vasculature in response to therapy.
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Affiliation(s)
- C C Quarles
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226-0509, USA
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121
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Fukumura D, Jain RK. Tumor microenvironment abnormalities: Causes, consequences, and strategies to normalize. J Cell Biochem 2007; 101:937-49. [PMID: 17171643 DOI: 10.1002/jcb.21187] [Citation(s) in RCA: 405] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A solid tumor is an organ-like entity comprised of neoplastic cells and non-transformed host stromal cells embedded in an extracellular matrix. The expression of various genes is influenced by interactions among these cells, surrounding matrix, and their local physical and biochemical microenvironment. The products encoded by these genes, in turn, control the pathophysiological characteristics of the tumor, and give rise to the abnormal organization, structure, and function of tumor blood vessels. These abnormalities contribute to heterogeneous blood flow, vascular permeability, and microenvironment. Proliferating tumor cells produce solid stress which compresses blood and lymphatic vessels. As a result of vessel leakiness and lack of functional lymphatics, interstitial fluid pressure is significantly elevated in solid tumors. Each of these abnormalities forms a physiological barrier to the delivery of therapeutic agents to tumors. Furthermore, the metabolic microenvironment in tumors such as hypoxia and acidosis hinder the efficacy of anti-tumor treatments such as radiation therapy and chemotherapy. A judicious application of anti-angiogenic therapy has the potential to overcome these problems by normalizing the tumor vessels and making them more efficient for delivery of oxygen and drugs. Combined anti-angiogenic and conventional therapies have shown promise in the clinic.
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Affiliation(s)
- Dai Fukumura
- Department of Radiation Oncology, Edwin L Steele Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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Dickson PV, Hagedorn NL, Hamner JB, Fraga CH, Ng CYC, Stewart CF, Davidoff AM. Interferon beta-mediated vessel stabilization improves delivery and efficacy of systemically administered topotecan in a murine neuroblastoma model. J Pediatr Surg 2007; 42:160-5; discussion 165. [PMID: 17208558 DOI: 10.1016/j.jpedsurg.2006.09.052] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND We have recently demonstrated that continuous delivery of interferon beta (IFN-beta) stabilizes solid tumor vasculature and improves tumor perfusion. In this study, we have further investigated the functional consequences of this effect by assessing delivery and efficacy of conventional chemotherapy against neuroblastoma xenografts when used in combination with IFN-beta. METHODS Mice with established retroperitoneal tumors received adeno-associated virus vector encoding IFN-beta (AAV IFN-beta) or control vector. One week later, at 1 hour before sacrifice, a 1 mg/kg i.v. bolus of topotecan (TPT) was given. Intratumoral levels of TPT were measured by high-performance liquid chromatography and then standardized to plasma levels to determine tumor TPT penetration. Subsequent experiments evaluated the antitumor efficacy of topotecan alone or in combination with AAV IFN-beta. RESULTS As observed in prior experiments, AAV IFN-beta resulted in a marked increase in tumor vessel association with stabilizing perivascular smooth muscle cells. These more "matured" vessels facilitated improved tumor TPT penetration (51.2% +/- 4.2%) compared with controls (30.8% +/- 4.7%, P = .004). In additional cohorts of mice, this resulted in an improved antitumor effect. Mice with established tumors (301.8 +/- 18.1 mm3) were treated with TPT (1 mg/kg daily for 5 days for 2 consecutive weeks) either alone or in combination with AAV IFN-beta (5 x 10(10) vector particles per mouse). Topotecan monotherapy resulted in a reduction in mean tumor volume of 12% (264.2 +/- 65.8 mm3, P = .66). However, when the same regimen was administered to mice receiving continuous IFN-beta therapy, a 61% (118.9 +/- 42.3 mm3, P = .004) reduction in mean tumor volume was achieved. CONCLUSION Interferon beta-mediated vessel stabilization resulted in improved intratumoral delivery of systemically administered TPT, enhancing its antitumor efficacy. This approach of altering the tumor vasculature provides a strategy to help overcome solid tumor resistance to traditional cytotoxic agents.
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Affiliation(s)
- Paxton V Dickson
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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123
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Horsman MR, Siemann DW. Pathophysiologic Effects of Vascular-Targeting Agents and the Implications for Combination with Conventional Therapies. Cancer Res 2006; 66:11520-39. [PMID: 17178843 DOI: 10.1158/0008-5472.can-06-2848] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A functional vascular supply is critical for the continued growth and development of solid tumors. It also plays a major role in metastatic spread of tumor cells. This importance has led to the concept of targeting the vasculature of the tumor as a form of cancer therapy. Two major types of vascular-targeting agent (VTA) have now emerged: those that prevent the angiogenic development of the neovasculature of the tumor and those that specifically damage the already established tumor vascular supply. When used alone neither approach readily leads to tumor control, and so, for VTAs to be most successful in the clinic they will need to be combined with more conventional therapies. However, by affecting the tumor vascular supply, these VTAs should induce pathophysiologic changes in variables, such as blood flow, pH, and oxygenation. Such changes could have negative or positive influences on the tumor response to more conventional therapies. This review aims to discuss the pathophysiologic changes induced by VTAs and the implications of these effects on the potential use of VTAs in combined modality therapy.
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Affiliation(s)
- Michael R Horsman
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
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Abstract
Since the relationship between angiogenesis and tumor growth was established by Folkman in 1971, scientists have made efforts exploring the possibilities in treating cancer by targeting angiogenesis. Inhibition of angiogenesis growth factors and administration of angiogenesis inhibitors are the basics of anti-angiogenesis therapy. Transfer of anti-angiogenesis genes has received attention recently not only because of the advancement of recombinant vectors, but also because of the localized and sustained expression of therapeutic gene product inside the tumor after gene transfer. This review provides the up-to-date information about the strategies and the vectors studied in the field of anti-angiogenesis cancer gene therapy.
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Affiliation(s)
- Ching-Chiu Liu
- Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Chemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
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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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Jain RK, Duda DG, Clark JW, Loeffler JS. Lessons from phase III clinical trials on anti-VEGF therapy for cancer. ACTA ACUST UNITED AC 2006; 3:24-40. [PMID: 16407877 DOI: 10.1038/ncponc0403] [Citation(s) in RCA: 785] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2005] [Accepted: 11/17/2005] [Indexed: 12/14/2022]
Abstract
In randomized phase III trials two anti-vascular endothelial growth factor (VEGF) approaches have yielded survival benefit in patients with metastatic cancer. In one approach, the addition of bevacizumab, a VEGF-specific antibody, to standard chemotherapy improved overall survival in colorectal and lung cancer patients and progression-free survival in breast cancer patients. In the second approach, multitargeted tyrosine kinase inhibitors that block VEGF receptor and other kinases in both endothelial and cancer cells, demonstrated survival benefit in gastrointestinal stromal tumor and renal-cell-carcinoma patients. By contrast, adding bevacizumab to chemotherapy failed to increase survival in patients with previously treated and refractory metastatic breast cancer. Furthermore, addition of vatalanib, a kinase inhibitor developed as a VEGF receptor-selective agent, to chemotherapy did not show a similar benefit in metastatic colorectal cancer patients. These contrasting responses raise critical questions about how these agents work and how to combine them optimally. We summarize three of the many potential mechanisms of action of anti-VEGF agents, and also discuss progress relating to the identification of potential biomarkers for anti-VEGF-agent efficacy in humans.
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Affiliation(s)
- Rakesh K Jain
- Department of Radiation Oncology, Harvard Medical School, and Massachusetts General Hospital, Boston, MA 02114, USA.
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Li M, Ping G, Plathow C, Trinh T, Lipson KE, Hauser K, Krempien R, Debus J, Abdollahi A, Huber PE. Small molecule receptor tyrosine kinase inhibitor of platelet-derived growth factor signaling (SU9518) modifies radiation response in fibroblasts and endothelial cells. BMC Cancer 2006; 6:79. [PMID: 16556328 PMCID: PMC1458351 DOI: 10.1186/1471-2407-6-79] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Accepted: 03/24/2006] [Indexed: 11/10/2022] Open
Abstract
Background Several small receptor tyrosine kinase inhibitors (RTKI) have entered clinical cancer trials alone and in combination with radiotherapy or chemotherapy. The inhibitory spectrum of these compounds is often not restricted to a single target. For example Imatinib/Gleevec (primarily a bcr/abl kinase inhibitor) or SU11248 (mainly a VEGFR inhibitor) are also potent inhibitors of PDGFR and other kinases. We showed previously that PDGF signaling inhibition attenuates radiation-induced lung fibrosis in a mouse model. Here we investigate effects of SU9518, a PDGFR inhibitor combined with ionizing radiation in human primary fibroblasts and endothelial cells in vitro, with a view on utilizing RTKI for antifibrotic therapy. Methods Protein levels of PDGFR-α/-β and phosphorylated PDGFR in fibroblasts were analyzed using western and immunocytochemistry assays. Functional proliferation and clonogenic assays were performed (i) to assess PDGFR-mediated survival and proliferation in fibroblasts and endothelial cells after SU9518 (small molecule inhibitor of PDGF receptor tyrosine kinase); (ii) to test the potency und selectivity of the PDGF RTK inhibitor after stimulation with PDGF isoforms (-AB, -AA, -BB) and VEGF+bFGF. In order to simulate in vivo conditions and to understand the role of radiation-induced paracrine PDGF secretion, co-culture models consisting of fibroblasts and endothelial cells were employed. Results In fibroblasts, radiation markedly activated PDGF signaling as detected by enhanced PDGFR phosphorylation which was potently inhibited by SU9518. In fibroblast clonogenic assay, SU9518 reduced PDGF stimulated fibroblast survival by 57%. Likewise, SU9518 potently inhibited fibroblast and endothelial cell proliferation. In the co-culture model, radiation of endothelial cells and fibroblast cells substantially stimulated proliferation of non irradiated fibroblasts and vice versa. Importantly, the RTK inhibitor significantly inhibited this paracrine radiation-induced fibroblast and endothelial cell activation. Conclusion Radiation-induced autocrine and paracrine PDGF signaling plays an important role in fibroblast and endothelial cell proliferation. SU9518, a PDGFR tyrosine kinase inhibitor, reduces radiation-induced fibroblast and endothelial cell activation. This may explain therapeutic anticancer effects of Imatinib/Gleevec, and at the same time it could open a way of attenuating radiation-induced fibrosis.
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Affiliation(s)
- Minglun Li
- Department of Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
- University of Heidelberg Medical School, Heidelberg, Germany
- Department of Radiation Oncology, University Hospital Tuebingen, Germany
| | - Gong Ping
- Department of Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
- University of Heidelberg Medical School, Heidelberg, Germany
| | - Christian Plathow
- University of Heidelberg Medical School, Heidelberg, Germany
- Department of Diagnostic Radiology, University Hospital Tuebingen, Germany
| | - Thuy Trinh
- Department of Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
- University of Heidelberg Medical School, Heidelberg, Germany
| | | | - Kai Hauser
- Department of Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
- University of Heidelberg Medical School, Heidelberg, Germany
- Institucio Catalana de Recerca i Estudis Avancats (ICREA), Barcelona, Spain
- Department of Mathematics, University of California, Berkeley, CA, USA
| | - Robert Krempien
- Department of Clinical Radiology, University Hospital Heidelberg, Germany
| | - Juergen Debus
- Department of Clinical Radiology, University Hospital Heidelberg, Germany
| | - Amir Abdollahi
- Department of Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
- University of Heidelberg Medical School, Heidelberg, Germany
| | - Peter E Huber
- Department of Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
- University of Heidelberg Medical School, Heidelberg, Germany
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Beloueche-Babari M, Jackson LE, Al-Saffar NMS, Eccles SA, Raynaud FI, Workman P, Leach MO, Ronen SM. Identification of magnetic resonance detectable metabolic changes associated with inhibition of phosphoinositide 3-kinase signaling in human breast cancer cells. Mol Cancer Ther 2006; 5:187-96. [PMID: 16432178 DOI: 10.1158/1535-7163.mct-03-0220] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phosphoinositide 3-kinase (PI3K) is an attractive target for novel mechanism-based anticancer treatment. We used magnetic resonance (MR) spectroscopy (MRS) to detect biomarkers of PI3K signaling inhibition in human breast cancer cells. MDA-MB-231, MCF-7, and Hs578T cells were treated with the prototype PI3K inhibitor LY294002, and the (31)P MR spectra of cell extracts were monitored. In every case, LY294002 treatment was associated with a significant decrease in phosphocholine levels by up to 2-fold (P < 0.05). In addition, a significant increase in glycerophosphocholine levels by up to 5-fold was also observed (P <or= 0.05), whereas the content of glycerophosphoethanolamine, when detectable, did not change significantly. Nucleotide triphosphate levels did not change significantly in MCF-7 and MDA-MB-231 cells but decreased by approximately 1.3-fold in Hs578T cells (P = 0.01). The changes in phosphocholine and glycerophosphocholine levels seen in cell extracts were also detectable in the (31)P MR spectra of intact MDA-MB-231 cells following exposure to LY294002. When treated with another PI3K inhibitor, wortmannin, MDA-MB-231 cells also showed a significant decrease in phosphocholine content by approximately 1.25-fold relative to the control (P < 0.05), whereas the levels of the remaining metabolites did not change significantly. Our results indicate that PI3K inhibition in human breast cancer cells by LY294002 and wortmannin is associated with a decrease in phosphocholine levels.
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Affiliation(s)
- Mounia Beloueche-Babari
- Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT, United Kingdom.
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Hoang T, Huang S, Armstrong E, Eickhoff JC, Harari PM. Augmentation of radiation response with the vascular targeting agent ZD6126. Int J Radiat Oncol Biol Phys 2006; 64:1458-65. [PMID: 16488554 DOI: 10.1016/j.ijrobp.2005.11.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 11/10/2005] [Accepted: 11/11/2005] [Indexed: 11/18/2022]
Abstract
PURPOSE To examine the antivascular and antitumor activity of the vascular targeting agent ZD6126 in combination with radiation in lung and head-and-neck (H and N) cancer models. The overall hypothesis was that simultaneous targeting of tumor cells (radiation) and tumor vasculature (ZD6126) might enhance tumor cell killing. METHODS AND MATERIALS A series of in vitro studies using human umbilical vein endothelial cells (HUVEC) and in vivo studies in athymic mice bearing human lung (H226) and H and N (squamous cell carcinoma [SCC]1, SCC6) tumor xenografts treated with ZD6126 and/or radiation were performed. RESULTS ZD6126 inhibited the capillary-like network formation in HUVEC. Treatment of HUVEC with ZD6126 resulted in cell cycle arrest in G2/M, with decrease of cells in S phase and proliferation inhibition in a dose-dependent manner. ZD6126 augmented the cell-killing effect of radiation and radiation-induced apoptosis in HUVEC. The combination of ZD6126 and radiation further decreased tumor vascularization in an in vivo Matrigel angiogenesis assay. In tumor xenografts, ZD6126 enhanced the antitumor activity of radiation, resulting in tumor growth delay. CONCLUSIONS These preclinical studies suggest that ZD6126 can augment the radiation response of proliferating endothelial H and N and lung cancer cells. These results complement recent reports suggesting the potential value of combining radiation with vascular targeting/antiangiogenic agents.
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Affiliation(s)
- Tien Hoang
- Hematology/Oncology Division, Ohio State University College of Medicine, Columbus, OH, USA
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Abdollahi A, Griggs DW, Zieher H, Roth A, Lipson KE, Saffrich R, Gröne HJ, Hallahan DE, Reisfeld RA, Debus J, Niethammer AG, Huber PE. Inhibition of αvβ3 Integrin Survival Signaling Enhances Antiangiogenic and Antitumor Effects of Radiotherapy. Clin Cancer Res 2005; 11:6270-9. [PMID: 16144931 DOI: 10.1158/1078-0432.ccr-04-1223] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The involvement of alpha(v)beta3 and alpha(v)beta5 integrins in angiogenesis and the use of integrin antagonists as effective antiangiogenic agents are documented. Radiotherapy is an important therapy option for cancer. It has been shown that ionizing radiation exerts primarily antiangiogenic effects in tumors but has also proangiogenic effects as the reaction of the tumor to protect its own vasculature from radiation damage. Here, we show that combined treatment with S247, an Arg-Gly-Glu peptidomimetic antagonist of alpha(v)beta3 integrin, and external beam radiotherapy are beneficial in local tumor therapy. We found that radiation up-regulates alpha(v)beta3 expression in endothelial cells and consecutively phosphorylates Akt, which may provide a tumor escape mechanism from radiation injury mediated by integrin survival signaling. In the presence of S247, the radiation-induced Akt phosphorylation is strongly inhibited. Our studies on endothelial cell proliferation, migration, tube formation, apoptosis, and clonogenic survival show that the radiosensitivity of endothelial cells is enhanced by the concurrent administration of the integrin antagonist. The in vitro data are successfully translated into human glioma (U87), epidermoid (A431), and prostate cancer (PC3) xenograft models growing s.c. on BALB/c-nu/nu mice. In vivo, the combination of S247 treatment and fractionated radiotherapy (5 x 2.5 Gy) leads to enhanced antiangiogenic and antitumor effects compared with either monotherapies. These results underline the importance of alpha(v)beta3 integrin when tumors protect their microvasculature from radiation-induced damage. The data also indicate that the combination of integrin antagonists and radiotherapy represents a rational approach in local cancer therapy.
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Affiliation(s)
- Amir Abdollahi
- Department of Radiation Oncology, German Cancer Research Center, Heidelberg, Germany
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Ryan DP. The integration of biologic agents into the current systemic management of rectal cancer. CURRENT COLORECTAL CANCER REPORTS 2005. [DOI: 10.1007/s11888-005-0017-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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