Double-stranded ribonucleic acid decreases C6 rat glioma cell numbers: Effects on insulin-like growth factor I gene expression and action
Double-stranded ribonucleic acid decreases C6 rat glioma cell numbers: Effects on insulin-like growth factor I gene expression and action
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DOI：
10.1210/en.141.10.3546
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发表时间：
2000-10-01
期刊：
影响因子：
4.8
通讯作者：
Adamo, ML
中科院分区：
文献类型：
--
作者：
Chacko, MS;Adamo, ML
Poly（IC）是一种合成的肌苷酸和胞二酸的双链RNA共聚物，可以抑制正常细胞和致瘤细胞的生长。我们测试了Poly（IC）通过破坏自分泌胰岛素样生长因子I （IGF-I）生长环来降低C6胶质瘤细胞生长的假设。聚（IC）的加入减少了C6细胞数量在融合和稀疏培养呈剂量依赖性。外源IGF-I的加入部分补偿了C6细胞融合培养和亚融合培养中Poly（IC）导致的细胞数量减少，这表明Poly（IC）的作用机制之一是通过下调IGF-I基因的表达和/或作用。10 μ g/ml Poly（IC）和200 μ g/ml Poly（IC）处理C6细胞24 h后，IGF-I信使RNA （mRNA）水平分别降低至对照组的50%和25%。用200 μ g/ml Poly（IC）处理C6细胞24 h后，IGF-I受体mRNA水平降低至对照水平的50%。igf结合蛋白-1 （IGFBP-1）、-2和-6 mrna在本研究使用的C6细胞中未表达。用200 μ g/ml Poly（IC）处理C6细胞24 h后，IGFBP-4 mRNA和IGFBP-5 mRNA水平分别降低至对照水平的26%和29%。Poly（IC）治疗后，IGFBP-3、胰岛素受体或肌动蛋白mRNA水平无显著变化。用200 μ g/ml Poly（IC）处理融合C6细胞24 h，使条件培养基（CM）中免疫反应性IGF-I水平降至控制值的55%，IGF-1受体β亚基水平降至控制值的28%，CM中IGFBP-3、IGFBP-4和IGFBP-5蛋白水平分别降至控制值的45%、50%和30%。聚（IC）处理后，肌动蛋白和微管蛋白水平无显著变化。这些结果表明，Poly（IC）处理可下调IGF-I基因表达，IGF-I在C6细胞中的生物利用度和作用也因IGF-I受体和结合蛋白水平的降低而改变。
Poly(IC), a synthetic double-stranded RNA copolymer of inosinic and cytidilic acids, decreases the growth of normal and tumorigenic cells. We tested the hypothesis that Poly(IC) decreases C6 glioma cell growth by disrupting an autocrine insulin-like growth factor I (IGF-I) growth loop. Addition of Poly(IC) decreased C6 cell number in confluent and sparse cultures in a dose-dependent manner. Addition of exogenous IGF-I partially compensated for the decrease in cell number caused by Poly(IC) in confluent and subconfluent cultures of C6 cells, suggesting that one mechanism of Poly(IC) action is through down-regulation of IGF-I gene expression and/or action. Treatment of confluent C6 cells with 10 and 200 mu g/ml Poly(IC) for 24 h decreased IGF-I messenger RNA (mRNA) levels to 50% and 25% of the control value, respectively. Treatment of C6 cells with 200 mu g/ml Poly(IC) for 24 h reduced IGF-I receptor mRNA levels to 50% of the control level. IGF-binding protein-1 (IGFBP-1), -2, and -6 mRNAs were not expressed in the C6 cells used in this study. Treatment of C6 cells with 200 mu g/ml Poly(IC) for 24 h reduced IGFBP-4 mRNA and IGFBP-5 mRNA levels to 26% and 29% of the control level, respectively. There was no significant change in IGFBP-3, insulin receptor, or actin mRNA levels with Poly(IC) treatment. Treatment of confluent C6 cells with 200 mu g/ml Poly(IC) for 24 h decreased levels of immunoreactive IGF-I in conditioned medium (CM) to 55% of the control value, decreased IGF-1 receptor beta-subunit levels to 28% of the control value, and decreased levels of IGFBP-3, IGFBP-4, and IGFBP-5 protein in CM to 45%, 50%, and 30% of the control values, respectively. There was no significant change in actin and tubulin protein levels with Poly(IC) treatment. These results suggest that IGF-I gene expression is down-regulated by Poly(IC) treatment and that IGF-I bioavailability and action in C6 cells are also altered due to decreases in IGF-I receptor and binding protein levels.