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Updated: Jul 7, 2025
In vivo Imaging of Tumor Angiogenesis using Fluorescence Confocal Videomicroscopy
Published on: September 11, 2013
An In Vivo Dual-Observation Method to Monitor Tumor Mass and Tumor-Surface Blood Vessels for Developing
Tomoko Tachibana1,2, Tomoko Gowa Oyama3, Yukie Yoshii1,4
1Department of Molecular Imaging and Theranostics, National Institutes for Quantum Science and Technology (QST), Chiba 263-8555, Japan.
Abstract:
Managing metastasis at the early stage and detecting and treating submillimeter tumors at early metastasis are crucial for improving cancer prognosis. Angiogenesis is a critical target for developing drugs to detect and inhibit submillimeter tumor growth; however, drug development remains challenging because there are no suitable models for observing the submillimeter tumor mass and the surrounding blood vessels in vivo. We have established a xenograft subcutaneous submillimeter tumor mouse model with HT-29-RFP by transplanting a single spheroid grown on radiation-crosslinked gelatin hydrogel microwells. Here, we developed an in vivo dual-observation method to observe the submillimeter tumor mass and tumor-surface blood vessels using this model. RFP was detected to observe the tumor mass, and a fluorescent angiography agent FITC-dextran was administered to observe blood vessels via stereoscopic fluorescence microscopy. The anti-angiogenesis agent regorafenib was used to confirm the usefulness of this method. This method effectively detected the submillimeter tumor mass and tumor-surface blood vessels in vivo. Regorafenib treatment revealed tumor growth inhibition and angiogenesis downregulation with reduced vascular extremities, segments, and meshes. Further, we confirmed that tumor-surface blood vessel areas monitored using in vivo dual-observation correlated with intratumoral blood vessel areas observed via fluorescence microscopy with frozen sections. In conclusion, this method would be useful in developing anti-angiogenesis agents against submillimeter tumors.
Insights
Developing new anti-angiogenesis drugs for early-stage cancer is vital. This study introduces a novel in vivo dual-observation method to effectively monitor submillimeter tumors and their blood vessels, aiding drug development.
Area of Science:
- Oncology
- Biomedical Engineering
- Drug Development
Background:
- Early detection and management of metastasis, particularly submillimeter tumors, are critical for improving cancer patient outcomes.
- Angiogenesis is a key target for anti-cancer drug development, but observing submillimeter tumors and their vasculature in vivo remains a challenge.
- Existing models lack the capability to visualize both small tumor masses and their associated blood vessels simultaneously in living subjects.
Purpose of the Study:
- To develop and validate an in vivo dual-observation method for visualizing submillimeter tumors and their surface vasculature.
- To establish a reliable xenograft mouse model for studying early-stage tumor growth and angiogenesis.
- To assess the efficacy of anti-angiogenesis agents using the developed model and imaging technique.
Main Methods:
- Established a subcutaneous submillimeter tumor xenograft mouse model using HT-29-RFP cells grown on gelatin hydrogel microwells.
- Developed an in vivo dual-observation technique combining RFP fluorescence for tumor mass visualization and FITC-dextran for blood vessel imaging.
- Utilized stereoscopic fluorescence microscopy for high-resolution imaging of tumor and vasculature.
- Administered the anti-angiogenesis drug regorafenib to evaluate the model's responsiveness and the method's utility.
Main Results:
- The dual-observation method successfully visualized submillimeter tumor masses and their surface blood vessels in vivo.
- Regorafenib treatment demonstrated significant tumor growth inhibition and reduced angiogenesis, evidenced by decreased vascular networks.
- In vivo monitored tumor surface vasculature correlated well with ex vivo intratumoral vasculature, validating the imaging approach.
- The model and method proved effective in assessing the impact of anti-angiogenesis therapy on early-stage tumors.
Conclusions:
- The developed in vivo dual-observation method provides a powerful tool for studying submillimeter tumors and their vasculature.
- This model is suitable for preclinical evaluation of anti-angiogenesis drugs targeting early-stage metastatic disease.
- The findings support the advancement of therapeutic strategies aimed at inhibiting angiogenesis in small, early-stage tumors.
