Dynamic, Long-Term In Vivo Imaging of Tumor–Stroma Interactions in Mouse Models of Breast Cancer Using Spinning-Disk Confocal Microscopy

Abstract

INTRODUCTIONTumors contain many components in addition to the cancer cells, including blood vessels, fibroblasts, and immune cells. Genetic studies and tumor biopsies have generated insights into the importance of these stromal components for cancer progression. However, it remains a challenge to reveal the dynamic interactions among the distinct tumor components within live animals. Studies involving multiphoton microscopy allow direct imaging of cellular movement in live mice, but multiphoton microscopy is expensive, complex, and usually relies on a single excitation wavelength for all fluorophores. This article describes a method for intravital imaging using a microlensed spinning-disk confocal microscope. Although tissue penetration with spinning-disk confocal microscopy is lower than with multiphoton microscopy, image acquisition with this method is very rapid, so artifacts from respiratory motion are avoided. Photobleaching and phototoxicity are low, and multicolor acquisition is cheaper and easier than with multiphoton microscopy. This article discusses various aspects of experimental setup, as well as methods for addressing technical barriers, such as generating and working with multiple tumor microenvironments within individual live mice, image collection, and long-term anesthesia.