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Ex vivo Live Imaging of Lung Metastasis and Their Microenvironment
Published on: February 3, 2016
Ex vivo Live Cell Imaging of Nanoparticle-Cell Interactions in the Mouse Lung
Fernanda Ramos-Gomes1, Nathalia Ferreira1, Alexander Kraupner2
1Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany.
Abstract:
A successful clinical translation of novel nanoparticle-based cancer therapeutics requires a thorough preclinical investigation of their interaction with immune, tumor and endothelial cells as well as components of the tumor-microenvironment. Although high-resolution microscopy images of fixed tumor tissue specimens can provide valuable information in this regard, they are only static snapshots of a momentary event. Here we describe a superior alternative fluorescence microscopy approach to assess the feasibility of investigating nanoparticle-cell interactions in the mouse lung live and over time at nanometer resolution. We applied fluorescent lung tumor cells and Barium-based fluorescently labeled nanoparticles to nude mice or to CD68-EGFP transgenic mice for visualization of the monocyte-macrophage lineage. Shortly before imaging, fluorescently labeled lectin was intravenously injected for staining of the blood vessels. The lung was filled ex vivo with 1% agarose and individual lung lobes were imaged over time using a confocal microscope with Airyscan technology. Time series demonstrate that live cell imaging of lung lobes can be performed for at least 4 h post mortem. Time-lapse movies illustrate the dynamics of the nanoparticles within the pulmonary circulation and their uptake by immune cells. Moreover, the exchange of nanoparticle material between cancer cells was observed over time. Fluorescent monocytes in lungs of CD68-EGFP transgenic mice could be visualized within blood vessels in the process of interaction with tumor cells and nanoparticles. This high resolution ex vivo live cell imaging approach provides an excellent 4D tool to obtain valuable information on the behavior of tumor and immune cells at first encounter with nanoparticles and may contribute to the understanding of how nanoparticles interact with cells supporting the development of therapeutic strategies based on nanoparticulate drug delivery systems.
Insights
This study introduces an advanced ex vivo live imaging technique to track nanoparticle-cell interactions in mouse lungs. The method visualizes nanoparticle dynamics and immune cell uptake in real-time, aiding cancer therapeutic development.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Cancer Research
Background:
- Preclinical evaluation of nanoparticle therapeutics is crucial for clinical translation.
- Static microscopy of fixed tissues offers limited insight into dynamic nanoparticle-cell interactions.
- Understanding nanoparticle behavior in the tumor microenvironment is essential.
Purpose of the Study:
- To develop and validate a novel ex vivo live fluorescence microscopy approach for high-resolution, time-lapse imaging of nanoparticle-cell interactions in the mouse lung.
- To assess the feasibility of real-time investigation of nanoparticle dynamics, immune cell uptake, and intercellular exchange within the pulmonary microenvironment.
- To provide a 4D imaging tool for understanding initial nanoparticle-cell encounters to advance nanoparticulate drug delivery systems.
Main Methods:
- Utilized fluorescently labeled lung tumor cells and barium-based nanoparticles in nude and CD68-EGFP transgenic mice.
- Employed intravenous injection of fluorescent lectin for blood vessel visualization.
- Performed ex vivo confocal microscopy with Airyscan technology on agarose-embedded lung lobes for live imaging up to 4 hours post mortem.
Main Results:
- Demonstrated successful live cell imaging of mouse lung lobes ex vivo for extended periods (≥4 hours).
- Captured time-lapse movies revealing nanoparticle dynamics in pulmonary circulation and immune cell (monocyte-macrophage) uptake.
- Observed nanoparticle material exchange between cancer cells and visualized interactions between fluorescent monocytes, tumor cells, and nanoparticles.
Conclusions:
- The developed ex vivo live cell imaging technique provides a powerful 4D tool for studying nanoparticle-cell interactions at nanometer resolution.
- This approach offers valuable insights into the behavior of tumor and immune cells upon initial nanoparticle exposure.
- The findings support the advancement of nanoparticle-based drug delivery systems for cancer therapy.
