Molecular Imaging of Tumor Angiogenesis

Background: Tumor derived vascular endothelial growth factor (VEGF) can stimulate proliferation and migration of endothelial cells and recruit endothelial progenitor cells into tumors for vascular formation via a paracrine manner. Now increasing evidence suggests that VEGF also serves as an autocrine factor promoting cell survival and tumor angiogenesis. Real time visualization of VEGF activity in the early stages of tumor formation using molecular imaging will provide unprecedented insight into the biological processes of cancer. Methods: The mouse breast cancer cell line 4T1 was transfected with an inducible, bidirectional tetracycline (Bi-Tet) promoter driving VEGF and renilla luciferase (Rluc). This was used to quantitatively image conditional switching of VEGF by bioluminescence imaging (BLI) under the control of systemic administration of doxycycline. Simultaneously, 4T1 cells were labelled with the double fusion reporter gene (Fluc-eGFP) to establish a breast cancer model. Results: We found that inducible VEGF could promote proliferation and attenuate apoptosis due to oxidative stress in an autocrine manner in vitro. In vivo studies revealed that induction of VEGF expression during early tumor development not only dramatically enhanced tumor growth but also increased tumor angiogenesis as visualized by BLI. Finally, immunohistochemistry staining confirmed that inducing VEGF expression promoted cell survival and tumor neovascularization. Conclusion: Together the inducible bidirectional tetracycline (Bi-Tet) co-expression system combined with the dual bioluminescence imaging (BLI) system provides a platform to investigate a target gene’s role in the pathologic process of cancer and facilitates noninvasive monitoring of biological responses in real time.

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Molecular Imaging in Tumor Angiogenesis and Relevant Drug Research

International Journal of Biomedical Imaging ◽

10.1155/2011/370701 ◽

2011 ◽

Vol 2011 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Xibo Ma ◽

Jie Tian ◽

Xin Yang ◽

Chenghu Qin

Keyword(s):

Computed Tomography ◽

Molecular Imaging ◽

Tumor Angiogenesis ◽

Drug Research ◽

Single Photon ◽

Photon Emission ◽

Region Of Interest ◽

Emission Computed Tomography ◽

Positron Emission ◽

Novel Drug

Molecular imaging, including fluorescence imaging (FMI), bioluminescence imaging (BLI), positron emission tomography (PET), single-photon emission-computed tomography (SPECT), and computed tomography (CT), has a pivotal role in the process of tumor and relevant drug research. CT, especially Micro-CT, can provide the anatomic information for a region of interest (ROI); PET and SPECT can provide functional information for the ROI. BLI and FMI can provide optical information for an ROI. Tumor angiogenesis and relevant drug development is a lengthy, high-risk, and costly process, in which a novel drug needs about 10–15 years of testing to obtain Federal Drug Association (FDA) approval. Molecular imaging can enhance the development process by understanding the tumor mechanisms and drug activity. In this paper, we focus on tumor angiogenesis, and we review the characteristics of molecular imaging modalities and their applications in tumor angiogenesis and relevant drug research.

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