Detecting vascular changes in tumour xenografts using micro-ultrasound and micro-ct following treatment with VEGFR-2 blocking antibodies.

Blockade of vascular endothelial growth factor (VEGF) binding to its receptors on endothelial cells has been shown preclinically to induce tumour growth inhibition. Using ultrasound biomicroscopy (UBM) or micro-ultrasound imaging and micro-computed tomography (micro-CT) analysis, we have examined the effects of DC101, a highly specific vascular endothelial growth factor receptor-2 (VEGFR-2)-targeting antibody, in inducing growth inhibition and functional vascular changes in established melanoma (MeWo) xenografts in mice. Postprocessing of UBM imaging loops for speckle variance was introduced to estimate the level of functional blood flow in tumours. Perfused tumour area visualized by speckle variance revealed decreased blood flow within 48 h after DC101 injection (control versus DC101: 1.90 +/- 0.25% versus 1.01 +/- 0.11%, p < 0.01) and following a 3-wk DC101 therapy (control versus DC101: 0.76 +/- 0.14% versus 0.45 +/- 0.05%, p = 0.04), suggesting that VEGFR-2 blockade mediates both early and long-term effects on tumour blood flow. The growth of xenografts was significantly inhibited after treating with DC101 for 3 wk compared with controls. In addition to UBM, we examined the tumour vasculature in three-dimension (3D) using contrast-enhanced Micro-CT imaging, which displayed a reduction in the number of tumour vessels following extended VEGFR-2 blockade (vascular density of control versus DC101: 48.4 +/- 5.4% versus 20.6 +/- 1.8%). Lastly, decreased microvessel density (MVD) was noted in DC101-treated xenografts (3 wk) by performing immunohistochemical staining of endothelial marker CD34. Our study investigates tumour response to DC101 using complementing micro-ultrasound and micro-CT imaging tools.

[1]  A. Foss,et al.  Endothelial Cells of Tumor Vessels: Abnormal but not Absent , 2004, Cancer and Metastasis Reviews.

[2]  B. Fenton,et al.  Effect of VEGF receptor-2 antibody on vascular function and oxygenation in spontaneous and transplanted tumors. , 2004, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[3]  D. Hicklin,et al.  Therapy-Induced Acute Recruitment of Circulating Endothelial Progenitor Cells to Tumors , 2006, Science.

[4]  D. A. Christopher,et al.  Advances in ultrasound biomicroscopy. , 2000, Ultrasound in medicine & biology.

[5]  J. Gore,et al.  Correlation Between Estimates of Tumor Perfusion From Microbubble Contrast‐Enhanced Sonography and Dynamic Contrast‐Enhanced Magnetic Resonance Imaging , 2006, Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine.

[6]  Peter Bohlen,et al.  Continuous low-dose therapy with vinblastine and VEGF receptor-2 antibody induces sustained tumor regression without overt toxicity , 2000 .

[7]  R. Jain,et al.  Responses to antiangiogenesis treatment of spontaneous autochthonous tumors and their isografts. , 2003, Cancer research.

[8]  Keith A. Wear,et al.  Methods for Estimation of Statistical Properties of Envelopes of Ultrasonic Echoes from Myocardium , 1987, IEEE Transactions on Medical Imaging.

[9]  R Mark Henkelman,et al.  MicroCT scanner performance and considerations for vascular specimen imaging. , 2004, Medical physics.

[10]  Wolfhard Semmler,et al.  Dynamic contrast-enhanced magnetic resonance imaging rapidly indicates vessel regression in human squamous cell carcinomas grown in nude mice caused by VEGF receptor 2 blockade with DC101. , 2004, Neoplasia.

[11]  E. Ritman.  Micro-computed tomography-current status and developments. , 2004, Annual review of biomedical engineering.

[12]  F Forsberg,et al.  Assessment of angiogenesis: implications for ultrasound imaging. , 2004, Ultrasonics.

[13]  J M Rubin,et al.  Volume flow measurement using Doppler and grey-scale decorrelation. , 2001, Ultrasound in medicine & biology.

[14]  B. Zetter,et al.  Tumor vascularity: evaluation in a murine model with contrast-enhanced color Doppler US effect of angiogenesis inhibitors. , 2002, Radiology.

[15]  Rakesh K. Jain,et al.  Vascular Normalization by Vascular Endothelial Growth Factor Receptor 2 Blockade Induces a Pressure Gradient Across the Vasculature and Improves Drug Penetration in Tumors , 2004, Cancer Research.

[16]  D. Vray,et al.  High frequency ultrasound speckle flow imaging - comparison with Doppler optical coherence tomography (DOCT) , 2004, IEEE Ultrasonics Symposium, 2004.

[17]  Lei Xu,et al.  Kinetics of vascular normalization by VEGFR2 blockade governs brain tumor response to radiation: role of oxygenation, angiopoietin-1, and matrix metalloproteinases. , 2004, Cancer cell.

[18]  F. Stuart Foster,et al.  High-frequency color flow imaging of the microcirculation , 2000 .

[19]  C. Dinney,et al.  Anti-vascular endothelial growth factor receptor 2 antibody reduces tumorigenicity and metastasis in orthotopic prostate cancer xenografts via induction of endothelial cell apoptosis and reduction of endothelial cell matrix metalloproteinase type 9 production. , 2002, Clinical cancer research : an official journal of the American Association for Cancer Research.

[20]  Fabian Kiessling,et al.  Sensitive noninvasive monitoring of tumor perfusion during antiangiogenic therapy by intermittent bolus-contrast power Doppler sonography. , 2003, Cancer research.

[21]  M. Westphal,et al.  Inhibition of glioma angiogenesis and growth in vivo by systemic treatment with a monoclonal antibody against vascular endothelial growth factor receptor-2. , 2001, Cancer research.

[22]  E. Chérin,et al.  A new ultrasound instrument for in vivo microimaging of mice. , 2002, Ultrasound in medicine & biology.

[23]  Aaron Fenster,et al.  Three-dimensional ultrasound biomicroscopy for xenograft growth analysis. , 2005, Ultrasound in medicine & biology.

[24]  David E Goertz,et al.  High-frequency Doppler ultrasound monitors the effects of antivascular therapy on tumor blood flow. , 2002, Cancer research.

[25]  N. Fusenig,et al.  Rapid vessel regression, protease inhibition, and stromal normalization upon short-term vascular endothelial growth factor receptor 2 inhibition in skin carcinoma heterotransplants. , 2005, The American journal of pathology.

[26]  L. Ellis,et al.  Role of the vascular endothelial growth factor pathway in tumor growth and angiogenesis. , 2005, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[27]  D. Hanahan,et al.  Patterns and Emerging Mechanisms of the Angiogenic Switch during Tumorigenesis , 1996, Cell.

[28]  Wadih Arap,et al.  In vivo phage display and vascular heterogeneity: implications for targeted medicine. , 2002, Current opinion in chemical biology.

[29]  F. Foster,et al.  Estimation methods for flow imaging with high frequency ultrasound. , 2006, Ultrasonics.

[30]  R. Jain,et al.  Vascular endothelial growth factor receptor-2-blocking antibody potentiates radiation-induced long-term control of human tumor xenografts. , 2001, Cancer research.

[31]  R. Jain,et al.  Role of nitric oxide in tumor microcirculation. Blood flow, vascular permeability, and leukocyte-endothelial interactions. , 1997, The American journal of pathology.

[32]  L. Ellis,et al.  Inhibited growth of colon cancer carcinomatosis by antibodies to vascular endothelial and epidermal growth factor receptors , 2001, British Journal of Cancer.

[33]  Limor Chen,et al.  Targeted anti-vascular endothelial growth factor receptor-2 therapy leads to short-term and long-term impairment of vascular function and increase in tumor hypoxia. , 2006, Cancer research.

[34]  Transparent Window Models and Intravital Microscopy: Imaging Gene Expression, Physiological Function, and Drug Delivery in Tumors , 2001 .