Fluorescent Orthotopic Mouse Model: Implanting GFP Expressing Cancer Cells into Mouse for Assessing Tumor Progression In Vivo

- Cancer cells expressing green fluorescent protein or GFP enable monitoring tumor growth and metastasis by non-invasive optical imaging. We usually implant these cells into an orthotopic model, which allows the recreation of the tumor microenvironment and mimics the interaction of tumor cells with their surroundings.

Begin by placing an anesthetized mouse on a warm heating pad. Now, insert its nose into a nose mask to supply oxygen and isoflurane, an anesthetic. Using a scissor, make a small incision and cut the tissue. Gently pull out the spleen along with the pancreas and locate the pancreatic tail.

Load a syringe with fluorescent cancer cells suspension and gently inject it into the pancreatic tail. A superficial bubble appears at the injected site confirming successful implantation. Place the organs back into the body cavity and use a sterile suture to close the incision. Now, return the mouse to a cage and monitor it until recovery.

After the desired duration, place the mouse in an imaging chamber and take images. The light beam hits the cancer cells and excites the GFP, which, in turn, produces a green fluorescence. In the following protocol, we will perform surgical implant