GROWTH Inhibition of Gastrointestinal Cancers with Antisense Oligonucleotides to Oncogenes in vitro and in vivo.

在这项研究中，我们检测了癌基因的反义寡核苷酸在体外和体内是否可以抑制胃肠道肿瘤的生长。硫代修饰的c-myc和bcl2癌基因反义寡核苷酸在0.1~10muM浓度范围内呈剂量依赖性地抑制这两种癌基因高表达的胃癌细胞株MKN-45细胞的生长，而互补正义寡核苷酸则无此作用。Ki-ras癌基因的反义寡核苷酸也抑制了DLD-1细胞的生长，DLD-1是一种携带突变的Ki-ras基因的结肠癌细胞株。逆转录聚合酶链式反应和c-myc流式细胞术分析表明，c-myc反义寡核苷酸不仅在蛋白水平上，而且在mRNA水平上特异性地抑制了c-myc癌基因的表达。缺口末端标记法显示c-myc和bcl2反义寡核苷酸增加了MKN-45细胞的凋亡，提示其抑制MKN-45细胞生长可能与细胞凋亡有关。此外，c-myc和Ki-ras反义寡核苷酸可抑制裸鼠皮下移植的MKN-45细胞和DLD-1细胞的生长，而生理盐水和正义寡核苷酸则无此作用。这些结果表明，癌基因反义寡核苷酸有可能成为治疗胃肠道肿瘤的一种可能的方法。

In this study, we examined if antisense oligonucleotides to oncogenes can suppress growth of gastrointestinal cancers in vitro and in vivo. Phosphorothioate-modified antisense oligonucleotides to the c-myc and bcl-2 oncogenes depressed growth of MKN-45 cells, a gastric cancer cell line overexpressing both onccogenes, in a dose dependent manner at concentrations of 0.1-10muM in vitor, whereas the complementary sense oligonucleotides had no effect. Antisense oligonucleotide to the Ki-ras oncogene also inhibited growth of DLD-1 cells, a colon cancer cell line carrying a mutated Ki-ras gene. When analyzed by RT-PCR and c-myc flow cytometry, the c-myc antisense oligonucleotide specifically inhibited expression of the c-myc oncogene in mRNA level as well as in protein level. Nick-end labelling method for histological detection of apoptotic cells revealed that the c-myc and the bcl-2 antisense oligonucleotides increased apoptotic MKN-45 cells, suggesting that apoptosis may be involved in their inhibitory effect on MKN-45 cell growth. Further, antisense oligonucleotides to c-myc and Ki-ras suppressed growth of MKN-45 cells and DLD-1 cells subcutaneously transplanted in nude mice, whereas saline and sense oligonucleotides had no effect. These results suggest that antisense oligonucleotides to oncogenes might be further studied as a possible treatment method for gastrointestinal cancers.