Modulation of c-fms proto-oncogene in an ovarian carcinoma cell line by a hammerhead ribozyme

Abstract

Summary Co-expression of macrophage colony-stimulating factor (M-CSF) and its receptor (c-fms) is often found in ovarian epithelial carcinoma, suggesting the existence of autocrine regulation of cell growth by M-CSF. To block this autocrine loop, we have developed hammerhead ribozymes against c-fms mRNA. As target sites of the ribozyme, we chose the GUC sequence in codon 18 and codon 27 of cfms mRNA. Two kinds of ribozymes were able to cleave an artificial c-fms RNA substrate in a cell-free system, although the ribozyme against codon 18 was much more efficient than that against codon 27. We next constructed an expression vector carrying a ribozyme sequence that targeted the GUC sequence in codon 18 of c-fms mRNA. It was introduced into TYK-nu cells that expressed M-CSF and its receptor. Its transfectant showed a reduced growth potential. The expression levels of c-fms protein and mRNA in the transfectant were clearly decreased with the expression of ribozyme RNA compared with that of an untransfected control or a transfectant with the vector without the ribozyme sequence. These results suggest that the ribozyme against GUC in codon 18 of c-fms mRNA is a promising tool for blocking the autocrine loop of M-CSF in ovarian epithelial carcinoma.

Ribozyme-mediated cleavage of the human survivin mRNA and inhibition of antiapoptotic function of survivin in MCF-7 cells

“…31,32 Therefore, it is being increasingly considered and used as gene therapeutic agent for human malignancies. 33,34 In the present study, as an alternative strategy for survivin inhibition, we designed two hammerhead ribozymes against human survivin mRNA and examined the function of the ribozymes and the effects of developing the ribozymes as a tool of cancer gene therapy on the antiapoptosis of survivin in MCF -7 cells.…”

Genetic factors in ovarian carcinoma

“…Yokoyama et al [38] developed hammerhead ribozymes against the GUC sequence in codon 18 and codon 27 of c-fms mRNA; transfection into TYK-nu cells expressing CSF-1 and its receptor resulted in reduced growth potential as well as decreased expression of c-fms protein and mRNA [38].…”