RNAi阻断NPM-ALK基因表达及对大细胞间变性淋巴瘤细胞的影响(英文)

Effects of RNA interference on NPM-ALK fusion gene expression in anaplastic large-cell lymphoma cells

目的应用RNA干扰技术抑制大细胞间变性淋巴瘤细胞系(Karpas299)中NPMALK融合基因表达,观察其对肿瘤细胞生长的影响。方法针对NPMALK融合位点设计两个siRNA序列siRNAI与siRNAII,经PCR反应构建含U6启动子siRNA正义和反义线性表达载体,通过脂质体转染Karpas299细胞,应用实时荧光定量RTPCR、Westernblot检测siRNA片段对NPMALKmRNA和蛋白表达的抑制作用,MTT、Hoechst荧光染色检测siRNA对肿瘤细胞生长的影响。结果siRNAI可导致NPMALKmRNA下降约75%(P<0.05),转染72h后可导致蛋白表达下降;转染siRNAII细胞NPMALKmRNA下降为35%(P<0.05),但蛋白水平无明显改变。转染siRNAI的细胞可抑制Karpas299细胞的增殖和诱导凋亡发生,siRNAII则无明显的抑制增殖和诱导凋亡作用。结论含有针对NPMALK融合位点特异siRNA序列的U6表达载体,可特异地抑制NPMALK基因mRNA和蛋白的表达,并能抑制大细胞间变性淋巴瘤肿瘤细胞株Karpas299细胞的增殖,导致肿瘤细胞凋亡增加,提示NPMALK融合基因的异常表达与大细胞间变性淋巴瘤形成密切相关,为研究NPMALK基因功能和大细胞间变性淋巴瘤基因靶向治疗提供了新策略。

Objective To evaluate two small interfering RNAs (siRNAs) on the NPM-ALK fusion gene expression in anaplastic large-cell lymphoma cell line Karpas299, and to study the effect of RNA interference on Karpas299 cells proliferation. Methods Two siRNAs sequences (siRNA- I and siRNA-II) were designed to target the NPM-ALK fusion site in anaplastic large-cell lymphoma cell line Karpas299. An siRNA U6 expression system including U6 RNA-based polymerase III promoter was set up. The two siRNAs designed for down-regulation of the NPM-ALK fusion mRNA were transfected into Karpas299 cells by liposomal transfection reagents. The effect of RNAi on NPM-ALK mRNA expression was detected by real-time RT-PCR and Western blot. The anti-proliferative effects of the siRNA U6 system were assessed using MTT. Apoptosis was observed by fluorescence microscopy. Results The mRNA level of NPM-ALK in Karpas299 cells transfected with siRNA-I and siRNA-II decreased by approximately 75% and 35% respectively. The NPM-ALK protein expression was inhibited in Karpas299 cells at 72 hrs of siRNA-I transfection. The siRNA-II treatment had no effect on NPM-ALK protein expression. siRNA-I had inhibitory effects on Karpas299 cells proliferation and induced the cells apoptosis, while siRNA-II did not. Conclusions Sequence specific siRNAs targeting NPM-ALK was capable of suppressing NPM-ALK expression and inhibiting cellular proliferation. RNA interference may be a suitable technique for studying the function of NPM-ALK gene and may be used to develop siRNA-based targeted gene therapeutic approaches against NPM-ALK-positive lymphomas.