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Non-invasive In Vivo Fluorescence Optical Imaging of Inflammatory MMP Activity Using an Activatable Fluorescent Imaging Agent
Published on: May 8, 2017
Development of membrane type-1 matrix metalloproteinase-specific activatable fluorescent probe for malignant tumor
Yoichi Shimizu1, Takashi Temma, Kohei Sano
1Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
Abstract:
Membrane type-1 matrix metalloproteinase (MT1-MMP) is a protease that activates pro-MMP-2 and pro-MMP13, which are related to tumor malignancy. Therefore, probes that specifically image MT1-MMP would be useful for malignant tumor diagnosis. In the present study, we prepared rhodamine X-conjugated anti-MT1- MMP antibody (anti-MT1-MMP mAb-ROX) as an activatable fluorescent probe and evaluated its usefulness for MT1-MMP-specific imaging. Anti-MT1-MMP mAb-ROX was obtained in a quenched form with approximately three ROX molecules per mAb. Its fluorescence intensity increased approximately 14-fold in the presence of detergent, which is suitable for activatable systems. C6 glioma cells and MCF-7 human breast adenocarcinoma cells were used as MT1-MMP-positive and MT1-MMP-negative models, respectively. The fluorescence intensity of C6 cells treated with anti-MT1-MMP mAb-ROX, but not ROX-conjugated isotype control antibody (NC Ab-ROX), increased with time and was significantly higher than that of MCF-7 cells at 6 h (P < 0.001). The fluorescence intensity of cells treated with anti-MT1-MMP mAb-ROX was also suppressed by pre-treatment with a MT1-MMP endocytosis inhibitor (P < 0.05). Furthermore, the probes were intravenously administered to C6 and MCF-7 xenografted mice. The tumor-to-muscle (T/M) ratio of the anti-MT1-MMP mAb-ROX group was 15.1 ± 3.2 at 48 h and was significantly higher than that of the NC Ab-ROX group (T/M ratio = 4.6 ± 3.0, P < 0.05) in C6 xenografted mice, while the T/M ratio of the anti-MT1-MMP mAb-ROX and NC Ab-ROX groups was not different in MCF-7 xenografted mice. These findings suggest that anti-MT1-MMP mAb-ROX is a promising probe for specifically detecting MT1-MMP-expressing tumors.
Insights
A novel fluorescent probe, anti-MT1-MMP mAb-ROX, specifically detects membrane type-1 matrix metalloproteinase (MT1-MMP) in tumors. This probe shows promise for improved malignant tumor diagnosis and imaging.
Area of Science:
- Biomedical imaging
- Molecular oncology
- Antibody-based diagnostics
Background:
- Membrane type-1 matrix metalloproteinase (MT1-MMP) is crucial in tumor malignancy by activating pro-MMPs.
- Targeted imaging of MT1-MMP is needed for accurate diagnosis of malignant tumors.
Purpose of the Study:
- To develop and evaluate an activatable fluorescent probe for specific MT1-MMP imaging.
- To assess the probe's efficacy in vitro and in vivo for tumor detection.
Main Methods:
- Preparation of rhodamine X-conjugated anti-MT1-MMP antibody (anti-MT1-MMP mAb-ROX) as a quenched fluorescent probe.
- In vitro evaluation using MT1-MMP-positive (C6 glioma) and negative (MCF-7 breast cancer) cell lines.
- In vivo studies using xenografted mice to assess tumor targeting and imaging.
Main Results:
- The anti-MT1-MMP mAb-ROX probe exhibited a 14-fold increase in fluorescence intensity in the presence of detergent.
- Significantly higher fluorescence was observed in MT1-MMP-positive C6 cells compared to negative MCF-7 cells.
- In vivo studies showed a higher tumor-to-muscle ratio in mice bearing MT1-MMP-expressing tumors treated with the probe.
Conclusions:
- Anti-MT1-MMP mAb-ROX is an effective activatable fluorescent probe for MT1-MMP detection.
- The probe demonstrates specificity and potential for diagnosing MT1-MMP-expressing malignant tumors.
