Therefore, Livin as a target gene for treating bladder cancer has a good application prospect. Antisense nucleic acid is a naturally existing or synthetic nucleotide sequence. Livin ASODN hybridizes with target genes through Watson Crick principle of complementary base pairing to prevent gene expression, inhibit cell proliferation, promote apoptosis, and achieve the purpose of preventing or treating tumors. The natural oligonucleotide

see more is easily degraded, but phosphorathioate modifying can increase the capacity of its tolerance to nucleic acid hydrolysis, with good solubility and hybridization properties. The effectiveness and safety have been universally accepted by researchers. Currently the antisense oligonucleotide with bcl-2 as the target gene (trade name: Oblimersen) is in Phase III clinical trials with the permit of FDA (mainly treat malignant melanoma, chronic lymphocytic leukemia, multiple myeloma, etc.) [19]. The drug achieves the purpose of cancer treatment by inhibiting the expression of bcl-2 inside the tumor cells and inducing the tumor cell apoptosis. There are also a variety of antisense

oligonucleotides anticancer drugs in clinical trials [20, 21]. In the present study, phosphorathioate modifying greatly enhanced the anti-ribozyme decomposition capacity of buy SN-38 Livin ASODN. The supplement of cationic liposome transfection further increased its stability and improved the ability of uptake by cells. Using RT-PCR, Western blot, immunocytochemistry, immunohistochemistry, we found that Livin ASODN could inhibit the expression of Livin mRNA and protein. We further observed that the cell growth was inhibited and the apoptosis increased from MTT, flow cytometry, TUNEL method and morphological observations. GPX6 Caspases protein plays an important role in apoptosis. Most of the stimuli induce apoptosis through the Caspase protein cascade activation reactions. Caspases protein family has more than 10 members. Literatures have reported that Livin can interact with Caspase-3, -6, -7, -8, -9, -10 [22] (especially Caspase 3) to inhibit the process of apoptosis. Using

immunohistochemistry, we observed that after the injection of Livin ASODN, the expression of Caspase 3 in tumor tissues increased, which was probably because Livin ASODN inhibited the expression of Livin and then removed the binding inhibition to Caspase 3. Besides, Caspase 3 removal function also enhanced, which lead to increased cell apoptosis. In conclusion, Livin ASODN could specifically inhibit the expression of Livin in human bladder cancer cell 5637 and induce apoptosis of bladder cancer cells. It may be a potential and most promising strategy for bladder cancer. Acknowledgements This study was supported by research grant from Research Development Foundation of Health Bureau of ChongQing (No. 04-2-131). References 1.