全反式维甲酸诱导NB4细胞分化过程中TGF-β1/Smad信号途径蛋白表达的变化

Study on the protein expression of TGF-β1/Smad signal transduction pathway during the differentiation of NB4 cells induced by all-trans-retinoic acid

目的:观察在全反式维甲酸(ATRA)作用下,人急性早幼粒细胞白血病(APL)NB4细胞株转化生长因子β1(TGF-β1)/Smad信号转导途径中蛋白表达的变化,探讨TGF-β1/Smad途径在NB4细胞分化过程中的作用机制。方法:将ATRA作用于NB4细胞株不同时间后,应用蛋白印迹(Western blot)方法检测TGF-β1、Ⅰ型受体(TβRⅠ)、Ⅱ型受体(TβRⅡ)、Smad2、Smad4和Smad7蛋白表达的变化。结果:ATRA作用3h后TβRⅠ、TβRⅡ的表达量开始增加;12h后TGF-β1的表达量开始增加,随着加药时间延长,蛋白表达量逐渐上升,48h表达量至最高,然后下降。而Smad2、4、7蛋白的表达在加药3～6h后开始增加,呈逐渐上升趋势,Smad2表达量于48h达峰值,然后逐渐下降;而Smad4和Smad7的最高值出现较晚,出现在72h,然后下降。结论:TGF-β1信号转导途径与APL细胞的分化密切相关,ATRA在体外能上调TGF-β1/Smad途径的蛋白表达,以发挥抗白血病效应。

Objective To study the expression of transforming growth factor β1（TGF-β1）signaling pathway of human acute promyelocytic leukemia（APL） cell lines NB4 after exposed to all-trans-retinoic acid（ATRA）and to analyze its possible mechanism. Methods The protein expression levels of TGF-β1, TGF-β receptor Ⅰ （TβR Ⅰ）, TGF-β receptor Ⅱ （TβR Ⅱ ）, Smad2, Smad4 and Smad7 of NB4 cells exposed to all-trans-retinoic acid （ATRA） were analyzed using Western blot analysis. Results The expression levels of all these proteins increased during NB4 cells differentiation. The expression of TβR Ⅰ and TβR Ⅱ protein were increased within 3 hours, up to a peak in 48 hours, and dropped down up to 96 hours. Whereas, the degree of TGF-β1 remained unaffected until 12 hours following treatment, and then a modest increase was observed, which also peaked at 48 hours. The degree of Smad2 was increased at 3 hours after induced by ATRA, which peaked at 48 hours. The expressions levels of Smad4 and Smad7 were increased within 3 or 6 hours, up to a peak at 72 hours, which was later than Smad2, and then dropped down. Conclusions TGF-β1 pathway plays an important role in NB4 cells differentiation induced by ATRA which can significantly up-regulate this pathway.