Induction of apoptosis in human ovarian epithelial cancer cells by antisurvivin oligonucleotides

Abstract

Survivin, an anti-apoptosis gene that is abnormally overexpressed in a variety of human tumors, may play an important role in the carcinogenesis and drug resistance of cancer. This study was designed to explore the effects of liposome-survivin antisense oligonucleotide (Lip-ASODN) on the growth and apoptosis of human ovarian cancer cell lines, A2780 and SKOV3. To investigate the use of survivin as a therapeutic target on ovarian cancer, we carried out transfections with Lip-ASODN to induce apoptosis in ovarian cancer cell lines, A2780 and SKOV3. The expression of survivin mRNA and relative protein were evaluated separately by quantitative real-time RT-PCR and Western blot analysis. Cell proliferation inhibition was determined by methyl thiazolyl tetrazolium (MTT) assay, and the induced cell apoptosis was examined using flow cytometry (FCM) after Lip-ASODN transfection. Our results showed that the overexpression of survivin led to infinite carcino-proliferation, and survivin expression in the survivin-positive ovarian cancer cell line A2780 and SKOV3 cells was significantly and gradually reduced when transfected with Lip-ASODN at concentrations of 200, 400 and 600 nM by degrees. Lip-ASODN transfection induced greater apoptosis rates in the human ovarian cancer cell lines A2780 and SKOV3 (p<0.05). The growth inhibition and apoptotic rates of tumor cells change when treated with different concentrations of Lip-ASODN. The cell growth inhibition peak rate was reached when increasing Lip-ASODN concentration to 600 nM. Furthermore, time course evaluation showed that survivin protein expression was inhibited by Lip-ASODN within 12 h after transfection. We concluded that down-regulation of survivin by a targeted antisense oligonucleotide appears to be an effective gene therapy approach in the treatment of ovarian cancer.