Bladder Tumor Organoid Model: A Method for Orthotopic Transplantation of Bladder Organoids into Recipient Murine Bladder

Patient-derived tumor organoids are miniature tumors developed from the parent organ. On transplantation into an animal model, these organoids retain most of the phenotypic and genetic characteristics of the original tumor, enabling personalized cancer therapy. For instance, bladder cancer organoids stain positive for many cellular markers as their corresponding parental tumor.

To develop a tumor organoid model, begin with a culture of bladder tumor organoids. Add collagenase enzyme suspension to the organoid culture and incubate. Collagenase breaks down the matrix components. Now, add a prewarmed culture medium to release the free organoids in suspension. Centrifuge at low temperature to neutralize any residual collagenase activity and obtain the organoid pellet.

Discard the supernatant containing neutralized enzymes and degraded matrix components and resuspend the pellet in fresh media. Transfer the organoid suspension into a growth medium containing the basement membrane matrix. Subsequently, draw the organoid and media suspension into a syringe and inject it into the anterior wall of a surgically exposed, anesthetized nude mouse bladder.

The complex network of basement membrane matrix helps entrap the organoids and facilitates their integration with the bladder wall. The bladder wall mimics the parental-tumor microenvironment, allowing the organoids to develop into a tumor that reflects the morphology and pathogenesis of the original cancer.