C－myc反义寡聚脱氧核苷酸抑制人脑胶质瘤细胞系BT_（325）Myc蛋白合成和细胞增殖并诱导其分化的研究

目的：探讨在体外ｃ－ｍｙｃ反义核酸是否可通过阻断人脑胶质瘤细胞中ｃ－ｍｙｃ基因的表达而抑制细胞增殖并诱导分化．方法：人工合成与ｃ－ｍｙｃｍＲＮＡ起始码及其后四个密码子互补的寡聚脱氧核苷酸（简称反义核酸）片段，用它处理培养的ＢＴ３２５细胞，观察它对细胞增殖的影响．同时用免疫细胞化学方法检测细胞中Ｍｙｃ蛋白的水平以及能反映胶质瘤细胞分化的Ｓ－１００和ＧＦＡＰ两种蛋白的水平，分析这些指标的变化．结果：发现４ｕｍｏｌ／Ｌ的ｃ－ｍｙｃ反义核酸明显抑制ＢＴ３２５细胞的增殖和Ｍｙｃ蛋白的合成，且后者发生在加入反义核酸后１ｈ，并持续２４ｈ以上，而细胞增殖受抑制要到第５日才明显．从第２日到第５日细胞中Ｓ－１００和ＧＦＡＰ染色明显加深，反映细胞有分化趋势．用同样长度的无关序列寡聚脱氧核苷酸作对照，则未见上述变化，表明ｃ－ｍｙｃ反义核酸的作用是序列特异性的．结论：ｃ－ｍｙｃ反义核酸可特异地抑制ＢＴ３２５细胞中Ｍｙｃ蛋白的合成和细胞增殖，并能诱导其分化．

An antisense oligodeoxynucleotide targeted against c-myc mRNA in-hibits Myc protein synthesis and proliferation of BT325 glioblastomacells , and induces differentiation

Objective : The possibilities of inhibition of cell proliferation and induciton of its differentiation dueto Myc protein synthesis arrest by c-myc antisense in human glioblastoma cells have been explored. Methods :An antisense pentadecadeoxynucleotide complementary to the initiation codon and the next four codons of c-myc mRNA was synthesized with an automatic DNA synthesizer.Adding this c-myc antisense to BT325 cellculture, the cell number in each well was recorded daily, and the cellular levels of Myc protein,S-100 andGFAPwere immunocytochemically assayed. Results : It was found that 4 umol/L of c-myc antisenseoligodeoxynucleotide could significantly inhibit Myc protein synthesis in BT325 cells 1 h after administration,and the frank retardation of cell growth occurred at 5th day. From 2nd to 5th day, the cellular levels of S-100and GFAP obviously increased in contrast to the decreased Myc protein level, implying a tendency to differen-tiatAn irrelevant oligodeoxynucleotide of the same length(15-mer),used as contro, showed no such ef-fects , indicating that the effects of c-myc antisense was sequence-specific. Conclusjon:C-myc antisenseoligodeoxynucletide could specifically inhibit Myc protein synthesis in cultured BT325 cells, suppress prolifera-tion,and induce differentiaiton.