Abstract: To investigate the effects of the survivin antisense oligonucleotide(ASODN) on cell proliferation，apoptosis and chemosensitivity to paclitaxel in human breast cancer cells MCF-7. MethodsSurvivinASODN was transfected into MCF-7cells mediated by Lip reagent. The expression of survivin mRNA was determined by RT-PCR, cell proliferation and chemosensitivity to paclitaxel in MCF-7 were determined by MTT assay, and apoptosis and cell cycle were determined by flow cytometry. Results The antisense compound efficiently downregulated survivin mRNA expression in a timedependent manner. The growth inhibition rate of MCF-7 was decreased in a dose and timeindependent manner. The cell cycle was arrested at G₂/M phase; apoptosis was obviously found. Paclitaxel could enhance the expression of survivin at an early time, and this effect might play a critical role in the escape to apoptosis induced by paclitaxel, which may promote the resistance of paclitaxel. The antisense compound efficiently downregulated this induction by paclitaxel, and enhanced the chemosensitivity to paclitaxel in MCF7. ConclusionSurvivin antisense oligonucleotide effectively suppresses the expression of survivin mRNA, increases apoptosis and enhances the chemosensitivity to paclitaxel in MCF-7.

Key words: Breast neoplasms, Survivin oligoribonucleotides, antisense, Cell proliferation, Apoptosis, Chemosensitivity