Suppression of the neoplastic phenotype in vivo by an anti-ras ribozyme.

In this study, the efficacy of an anti-ras ribozyme in reversing the neoplastic phenotype was investigated. Murine NIH3T3 cells were transfected with cellular DNA from the FEMX-I human melanoma cell line expressing the activated H-ras gene. The transformed cells displayed the neoplastic phenotype in vitro and were tumorigenic in nude mice in vivo. When the transformants were transfected by a ribozyme designed to cleave only activated H-ras RNA, the transformed phenotype was abrogated. In contrast, expression of a mutant ribozyme, essentially acting only as antisense, into the transformed cells resulted in less dramatic changes in cell growth and tumorigenicity. These results reinforce the potential role of anti-oncogene ribozymes as suppressors of neoplastic growth, with possible implications for gene therapy.