| BackgroundEmerging novel strategies of cancer treatments are based on the selective regulation of specific targets, which are involved in the process of neoplastic transformation and progression. Glycosphingolipids(GSL) perform a wide variety of biological functions: formatting specialized structures, regulating the cell growth and differentiation , participating in cell-cell and cell-substratum interactions, modulating behaviors of cellular proteins and receptors and signal transductions. GSLs are also closely associated with neoplastic cell biological activities, such as growth, invasion, metastasis, antigenic regulation. Down regulating GSL expression by different inhibitors can cause cell growth arrest and differentiation in a variety of cancer cell lines, which has been verified with antitumor effect in nude mice experiments. For all of these reasons, Glycosphingolipids are recognized as a relevant target for therapeutic intervention of some cancer cells, and many kinds of GSL inhibitors are now under clinical developments. Globo-series glycolipids is a kind of neutral glycosphingolipids, including globotriosylceramide (Gb3), globoside (Gb4), stage-specific embryonic antigens 3 and 4 (SSEA-3 and -4), and so on. The over expression of Globo series glycosphgolipids is detected in some human cancers, including ovarian, glioma, breast, and germ cell cancers, and it relates with worse clinicopathological features in these tumor types, alpha 1,4 galactosyltransferase (alpha 1, 4 Gal-T) initiates the synthesis of Globo series glycolipids. By far, among all isolated genes, the a 1,4 galactosyltransferase gene is the only gene which has no significant homology with any other galactosyltransferases. Therefore, alpha 1, 4 Gal-T gene is a good and specific target for several cancer treatments.Antisense oligonucleotides(AsODN) can inhibit the expression of specific genes by binding to mRNA transcripts. A number of genes play key roles in-9-the development and maintenance of tumors. Many in vitro and in vivo studies have demonstrated that antisense oligonucleotides complementary to the mRNA of specific genes, which involve in neoplastic transformation and progression, are effective in inhibiting cancer cell growth.Ovarian cancer is the leading cause of death in gynecologic cancers. The level of Gb3 was as low as undetectable in "normal" ovarian tissue. However it was markedly increased in both benign and malignant ovarian rumors. By far the highest content of Gb3 was observed in secondary ovarian metastases and tumors refractory to chemotherapy. Therefore, a l,4Gal-T with altered mRNA expression in carcinoma tissue is a potential selectively target for therapeutic approaches.Objectivewe studied the influences of antisense phosphorothiaoate oligonucleotide against alpha 1,4 Gal-Ton ovary cancer cell lines by transfection. The inhibited expressions of the alpha 1,4Gal-T AsODN on alpha 1,4GaH mRNA and globo-series Glycosphingolipids were observed. The effects of the alpha 1,4 Gal-T AsODN on the cell growth, apoptosis, adhesion, invasion, multiple drug resistance, radiation and chemotherapy sensitizing were investigated. The objective of this study is to explore the influence of a l,4Gal-T on biological activities of ovary cancer cells, and to find a more effective treatment of ovary cancer with antisense therapies.Methods1. The antisense oligonucleotides alpha 1, 4 Gal-T were designed to target against the 18 codons following the AUG start codon of the a 1, 4 Gal-T mRNA, with the following sequence 5'-GGCGCCCAGGCTGACCAG-3'; the nonsense oligonucleotides (NODN) sequence 5'-GACCGTC GCGTGCACTGT-3'. The two internucleotide linkages at the 3' and 5' end of the oligonucleotides were phosphorothioates. Oligonucleotides were delivered into cultured ovary cancer cells COC1 by cationic liposomes. The oligonucleotide/lipid complex was obtained by adding oligonucleotide solution to liposomes solution, the oligonucleotides andliposomes have a ratio of 1:6(w/w). After inculation with the 10 U mol/L AsO...
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