EGF-related antisense oligonucleotides inhibit the proliferation of human ovarian carcinoma cells

Background: The epidermal growth factor (EGF)-like peptides CRIPTO (CR), amphiregulin (AR) and transforming growth factor alpha (TGF alpha) are expressed in human ovarian carcinomas. Materials and methods: The expression of AR, CR and TGF alpha in ovarian carcinoma cell lines was assessed by immunocytochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). The antiproliferative effects of antisense phosphorothioate oligodeoxynucleotides (AS S-Oligos) directed against either AR, CR or TGF alpha was evaluated by using a clonogenic assay. Results: A majority of the ovarian carcinoma cell lines was found to express TGF alpha, AR and CR mRNAs and proteins. AS S-Oligos directed against either AR, CR or TGF alpha were able to inhibit the anchorage-independent growth of NIH:OVCAR3 and NIH:OVCAR8 cells in a dose dependent manner. A 30%-50% growth inhibition was observed at a 2 mu M concentration of the AS S-Oligos. Treatment of these cells with combinations of EGF-related AS S-Oligos resulted in a more significant growth inhibition when compared to treatment with a single AS S-oligo. A 60%-75% growth inhibition was observed using combinations of AR, CR and TGF alpha AS S-oligos at a total concentration of 2 mu M. An additive growth-inhibitory effect occurred when ovarian carcinoma cells were exposed to the AS S-Oligos after treatment with either paclitaxel or cis-platinum. Conclusions: These data suggest that EGF-related peptides function as autocrine growth factors in ovarian carcinoma cells, and that they might represent targets for experimental therapy of ovarian carcinoma.