Inhibition of c-myc expression by phosphorothioate antisense oligonucleotide identifies a critical role for c-myc in the growth of human breast cancer.
Inhibition of c-myc expression by phosphorothioate antisense oligonucleotide identifies a critical role for c-myc in the growth of human breast cancer.
复制标题
硫代磷酸酯反义寡核苷酸对 c-myc 表达的抑制作用确定了 c-myc 在人类乳腺癌生长中的关键作用。
作者：
P. Watson;R. Pon;R. Shiu
在寻找雌激素在人类乳腺癌中作用机制中的关键基因时，我们之前发现雌激素会刺激雌激素依赖性（MCF-7）细胞中 c-myc 基因的转录。我们现在通过使用合成的反义 c-myc 硫代磷酸寡核苷酸特异性抑制 c-myc 蛋白的表达，研究了 c-myc 在雌激素刺激的 MCF-7 细胞生长中的作用。通过蛋白质印迹检测发现，在类固醇剥夺的细胞中，雌激素在 90 分钟内诱导 c-myc 蛋白表达增加 5 倍。将 MCF-7 细胞预先暴露于 10 microM c-myc 反义寡核苷酸，可对雌激素诱导的 c-myc 蛋白表达产生高达 95% 的抑制。反义-myc 寡核苷酸在 9 天内抑制雌激素刺激的细胞生长高达 75%，并且还对不依赖雌激素的 MDA-MB-231 细胞的生长产生细胞抑制作用，这些细胞显示出相对较高的 c-myc 组成型表达。有义-myc 和反义-pS2 寡核苷酸对任一细胞系中的 c-myc 蛋白水平或生长均没有影响。这些结果证明了反义硫代磷酸酯寡核苷酸的特异性和持久作用。此外，这些结果表明c-myc在乳腺癌细胞生长中发挥关键作用，并支持这样的假设：该基因雌激素调节的丧失可能是乳腺癌进展的一个重要因素。
In search of critical genes in the mechanism of estrogen action in human breast cancer, we previously showed that estrogen stimulates transcription of the c-myc gene in estrogen-dependent (MCF-7) cells. We have now examined the role of c-myc in estrogen-stimulated growth of MCF-7 cells through the use of a synthetic antisense c-myc phosphorothioate oligonucleotide to specifically inhibit expression of the c-myc protein. Estrogen induces a 5-fold increase in c-myc protein expression within 90 min in steroid-deprived cells, as detected by Western blot. Prior exposure of MCF-7 cells to 10 microM c-myc antisense oligonucleotide results in up to 95% inhibition of the c-myc protein expression induced by estrogen. Antisense-myc oligonucleotide inhibits estrogen-stimulated cell growth by up to 75% over 9 days and also exerts a cytostatic effect on the growth of estrogen-independent MDA-MB-231 cells which show relatively high, constitutive expression of c-myc. Sense-myc and antisense-pS2 oligonucleotides have no effect on c-myc protein level or growth in either cell line. These results demonstrate both the specific and durable effects of antisense phosphorothioate oligonucleotides. Furthermore, these results indicate a critical role for c-myc in the growth of breast cancer cells and support the hypothesis that loss of estrogen regulation of this gene may be an important factor in the progression of breast cancer.