Human retinoblastoma is caused by mutational inactivation of the retinoblastoma suppressor gene (RB). We have examined intraocular tumorigenicity of retinoblastoma cells in which RB expression was achieved by retroviral transduction. Retinoblastoma cells were injected into the anterior chambers of severe combined immunodeficient mouse eyes, and tumorigenicity was assessed. RB-expressing retinoblastoma cells usually failed to form progressive tumors in the anterior chamber, whereas the parental, RB-negative line, WERI-Rb27, was rapidly tumorigenic. These results support the hypothesis that inactivation of the RB gene is critical for the growth of retinoblastoma tumors. The potential use of RB reconstitution for treating human retinoblastoma is suggested by our finding that intraocular tumor growth can be suppressed by RB expression.
This work was supported by grants from the Knights Templar Eye Foundation and Fight for Sight, NSPB in tribute to Bob Hope (S. A. M.) and the NIH (W. H. L., R. A. P., J. W. H.).