Yoo Byong Hoon, Bochkareva Elena, Bochkarev Alexey, Mou Tung-Chung, Gray Donald M
Department of Molecular and Cell Biology, Mail Stop FO31, The University of Texas at Dallas, PO Box 830688, Richardson, TX 75083-0688, USA.
Nucleic Acids Res. 2004 Apr 2;32(6):2008-16. doi: 10.1093/nar/gkh516. Print 2004.
Antisense oligodeoxynucleotides (ODNs) have biological activity in treating various forms of cancer. The antisense effects of two types of 20mer ODNs, phosphorothioate-modified ODNs (S-ODNs) and S-ODNs with 12 2'-O-methyl groups (Me-S-ODNs), targeted to sites 109 and 277 of bcl-2 mRNA, were compared. Both types were at least as effective as G3139 (Genta, Inc.) in reducing the level of Bcl-2 protein in T24 cells following a 4 h transfection at a dose of 0.1 micro M. Circular dichroism spectra showed that both types formed A-form duplexes with the complementary RNA, and the melting temperatures were in the order of Me-S-ODN.RNA > normal DNA.RNA > S-ODN.RNA. In comparison with the S-ODN, the Me-S-ODN had reduced toxic growth inhibitory effects, was less prone to bind the DNA-binding domain A of human replication protein A, and was as resistant to serum nucleases. Neither type of oligomer induced apoptosis, according to a PARP-cleavage assay. Hybrids formed with Me-S-ODN sequences were less sensitive to RNase H degradation than those formed with S-ODN sequences. Despite this latter disadvantage, the addition of 2'-O-methyl groups to a phosphorothioate-modified ODN is advantageous because of increased stability of binding and reduced non-specific effects.
反义寡脱氧核苷酸（ODNs）在治疗多种癌症方面具有生物活性。比较了两种20聚体ODN，即硫代磷酸酯修饰的ODN（S-ODNs）和带有12个2'-O-甲基的S-ODN（Me-S-ODNs）对bcl-2 mRNA 109位和277位位点的反义作用。在0.1 μM剂量下转染4小时后，这两种类型的ODN在降低T24细胞中Bcl-2蛋白水平方面至少与G3139（Genta公司）一样有效。圆二色光谱表明，这两种类型的ODN均与互补RNA形成A-型双链体，解链温度顺序为Me-S-ODN.RNA＞正常DNA.RNA＞S-ODN.RNA。与S-ODN相比，Me-S-ODN的毒性生长抑制作用降低，与人复制蛋白A的DNA结合结构域A结合的倾向较小，并且对血清核酸酶具有抗性。根据PARP切割试验，这两种类型的寡聚物均未诱导细胞凋亡。与Me-S-ODN序列形成的杂交体比与S-ODN序列形成的杂交体对RNase H降解的敏感性更低。尽管有后一个缺点，但由于结合稳定性增加和非特异性作用降低，在硫代磷酸酯修饰的ODN上添加2'-O-甲基是有利的。
