OBJECTIVE

Bladder cancer is a common malignancy in which local recurrence and distant failure contribute to poor patient outcome. The search for improved therapies remains a high priority in this disease. For most experimental therapies animal tumor models represent an important step between in vitro testing and clinical trials. A useful animal model of bladder cancer involves the orthotopic implantation of bladder tumor cells in sygeneic animals. This model offers the opportunity to test the efficacy of therapies administered systemically or intravesically. However, quantitation of tumor growth has been difficult.

METHODS

To allow the quantitative assessment of tumor mass in this model and differentiate tumor cells from normal bladder epithelium at early stages of tumor growth we transfected cells of the MBT2 murine bladder cancer cell line with a vector encoding enhanced green fluorescent protein and devised an enzyme-linked immunosorbent assay that enables the detection of green fluorescent protein in cells at the pg. level.

RESULTS

Using this assay tumor growth can be detected 7 days after implantation and by 14 days levels of green fluorescent protein are more than 500-fold greater than in controls.

CONCLUSIONS

Combined with the enzyme-linked immunosorbent assay use of this MBT2 green fluorescent protein transfectant allows tumor cell growth to be monitored with sensitivity and reproducibility. It reduces the time required to measure effects on tumor growth to 2 weeks, while preserving the advantages of this orthotopic tumor model.