zPDX-Analysis of Invasiveness: Investigating Invasive Behavior of Metastatic Cancer Cells in Zebrafish Embryo Xenografts

Zebrafish embryo xenografts are useful in studying cancer cell invasion. Prepare xenograft models by injecting fluorescently labeled metastatic cancer cells and non-cancerous cells into the perivitelline space of two transgenic embryos. The perivitelline space is a space between the embryo periderm and the yolk sac. Let embryos grow for the desired period.

During this period, metastatic cancer cells divide aggressively in the injection site while non-cancerous cells remain stable. After incubation, use a pasteur pipette to transfer embryos into a glass bottom suspension dish. Remove excess egg water and position embryos in the desired position for imaging. Keep a cover slip on top of the dish and place the dish under a bright field microscope.

Capture images and analyze the invasive behavior of both types of cells. Metastatic cancer cells tend to invade blood vessels from the injection site. They move along the circulation, and then invade into the surrounding tissue to proliferate. In contrast, the non-cancerous cells remain at the site of injection. In the example protocol, we will inject breast cancer cells into the perivitelline space and duct of Cuvier in zebrafish xenograft models to study metastasis.

To visualize metastasis, with a pasteur pipette, transfer the injected zebrafish embryo to a glass bottom polystyrene dish and remove excess egg water. Image the whole body of the embryo with a confocal microscope set to low magnification to obtain a general pattern of tumor cell dissemination.

Use a 488 nanometer laser to visualize the zebrafish embryo vasculature and a 543 nanometer laser to visualize implanted tumor cells labeled with red fluorescent marker. Next, scan the embryo in eight to ten steps to acquire a high quality image.