A hammerhead ribozyme suppresses expression of hepatocyte growth factor/scatter factor receptor c-MET and reduces migration and invasiveness of breast cancer cells

Purpose: Hepatocyte growth factor/scatter factor (HGF/SF), via its receptor c-MET, has been implicated to play a pivotal role in breast cancer develop ment and progression. This study examined a transgene consisting of a combi nation of U1snRNA, hammerhead ribozyme, and antisense, designed to inhibit c-met expression-and its impact on the migration and in vitro invasion of b reast cancer cells. Experimental Design: A hammerhead ribozyme targeting human c-MET was cloned into a modified pZeoU1EcoSpe vector and transfected into breast cancer cel ls MDA NIB 231 and MCF-7 by electroporation. Expression of MET mRNA and pro tein was determined. Migration and in vitro invasiveness of transfected cel ls were also analyzed. Results: Breast cancer cells were transfected with the ribozyme-containing plasmids. Stable transfectants manifested an almost complete loss of MET mR NA and protein, as shown by reverse transcription-PCR, Northern blotting, a nd Western blotting, respectively, whereas the wild-type plasmid had no eff ects. Met-ribozyme transfected cells exhibited reduced migration and in vit ro invasiveness through extracellular matrix (Matrigel), compared with the wildtype cells and cells transfected with empty plasmid. Conclusions: These data show that targeting c-MET by way of a hammerhead ri bozyme encoding antisense to c-MET is an effective approach in reducing the invasiveness of breast cancer cells.