In the pathogenesis of bone metastasis, angiogenesis is a crucial process and therefore represents a target for imaging and therapy. Here, we present a rat model of site-specific breast cancer bone metastasis and describe strategies to non-invasively image angiogenesis in vivo using magnetic resonance imaging, volumetric computed tomography and ultrasound.
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Method Article
Multi-modal Imaging of Angiogenesis in a Nude Rat Model of Breast Cancer Bone Metastasis Using Magnetic Resonance Imaging, Volumetric Computed Tomography and Ultrasound
In This Article
Summary
Abstract
Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell proliferation in the bone marrow cavity as well as for interaction of tumor and bone cells resulting in local bone destruction. Our aim was to develop a model of experimental bone metastasis that allows in vivo assessment of angiogenesis in skeletal lesions using non-invasive imaging techniques.
For this purpose, we injected 105 MDA-MB-231 human breast cancer cells into the superficial epigastric artery, which precludes the growth of metastases in body areas other than the respective hind leg1. Following 25-30 days after tumor cell inoculation, site-specific bone metastases develop, restricted to the distal femur, proximal tibia and proximal fibula1. Morphological and functional aspects of angiogenesis can be investigated longitudinally in bone metastases using magnetic resonance imaging (MRI), volumetric computed tomography (VCT) and ultrasound (US).
MRI displays morphologic information on the soft tissue part of bone metastases that is initially confined to the bone marrow cavity and subsequently exceeds cortical bone while progressing. Using dynamic contrast-enhanced MRI (DCE-MRI) functional data including regional blood volume, perfusion and vessel permeability can be obtained and quantified2-4. Bone destruction is captured in high resolution using morphological VCT imaging. Complementary to MRI findings, osteolytic lesions can be located adjacent to sites of intramedullary tumor growth. After contrast agent application, VCT angiography reveals the macrovessel architecture in bone metastases in high resolution, and DCE-VCT enables insight in the microcirculation of these lesions5,6. US is applicable to assess morphological and functional features from skeletal lesions due to local osteolysis of cortical bone. Using B-mode and Doppler techniques, structure and perfusion of the soft tissue metastases can be evaluated, respectively. DCE-US allows for real-time imaging of vascularization in bone metastases after injection of microbubbles7.
In conclusion, in a model of site-specific breast cancer bone metastases multi-modal imaging techniques including MRI, VCT and US offer complementary information on morphology and functional parameters of angiogenesis in these skeletal lesions.
Protocol
1. Cell Culture
- Culture MDA-MB-231 human breast cancer cells (American Type Culture Collection) in RPMI-1640 (Invitrogen, Germany) supplemented with 10% FCS (Sigma, Germany). Keep all cultures under standard conditions (37 °C, humidified atmosphere, 5% CO2) and passage the cells 2-3 times a week to keep them in logarithmic growth. For the animal model described below, there is no need for usage of bone-specific sublines of MDA-MB-231 cells as the tumor take rate is over 90%1.
- Harvest sub-confluent tumor cells after using 2 mM EDTA in PBS- (phosphate-buffered saline without Ca2+ and Mg2+) and 0.25% tryps....
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Discussion
The method of inducing experimental bone metastases presented here in combination with the imaging procedures enable to follow-up osteolytic lesions in nude rats longitudinally. In our model, MDA-MB-231 human breast cancer cells are injected into the SEA which is an anastomosis between the iliac artery via the pudendoepigastric trunk and the femoral artery. Consequently, the blood flow into the supplied region of the knee joint is maintained after ligation of the SEA. The advantages of this model as compared to establish.......
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Disclosures
No conflicts of interest declared.
Acknowledgements
This work was supported by the Deutsche Forschungsgemeinschaft (SFB-TR 23 and SFB-TR 79, T.B. and D.K.). The authors would like to thank Renate Bangert, Karin Leotta and Lisa Seyler for excellent technical assistance.
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| MDA-MB-231 human breast cancer cells | American Type Culture Collection | HTB-26 | |
| RPMI-1640 | Invitrogen | 61870 | |
| FCS | Invitrogen | 10270 | |
| Trypsin-EDTA | Invitrogen | 25300 | |
| Carprofen Rimadyl | Pfizer Pharma GmbH | PZN 110208 | |
| Magnevist | Bayer-Schering | PZN 6961516 | |
| Imeron 400 MCT | Bracco | PZN 228654 | |
| SonoVue | Bracco | PZN 1567358 | |
| Papaverin | Alfa Aesar | L 04152 | |
| Isofluran | Baxter Internationl Inc. | HDG 9623 | |
| Symphony (Magnetic resonance imaging) | Siemens AG | ||
| Volume CT (Volumetric computed tomography) | Siemens AG | ||
| Acuson Sequioa 512 (Ultrasound) | Siemens-Acuson |
References
- Bäuerle, T. Characterization of a rat model with site-specific bone metastasis induced by MDA-MB-231 breast cancer cells and its application to the effects of an antibody against bone sialoprotein. Int. J. Cancer. 115, 177-186 (2005).
- Merz, M., Komljenovic, D., Zwick, S., Semmler, W., Bäuerle, T.
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