Yi Zong-chun, Wang Zhao, Li Hai-xia, Liu Ming-jie, Wu Rong-cong, Wang Xiao-hui
Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
Acta Pharmacol Sin. 2004 Feb;25(2):231-8.
To study effects of chebulinic acid on erythroid and megakaryocytic differentiation in K562 cells.
The benzidine staining method was used to evaluate hemoglobin synthesis; the expression of erythroid specific glycophorin A (GPA) protein and megakaryocytic surface marker CD61 was determined by flow cytometry using fluorescence labeled antibodies; erythroid and megakaryocytic mRNA expression was analyzed by RT-PCR.
During erythroid differentiation induced by butyric acid (BA) or hemin, chebulinic acid not only inhibited the hemoglobin synthesis of BA- and hemin-treated K562 cells in concentration-dependent manner with IC50 of 4 micromol/L and 40 micromol/L respectively, but also inhibited another erythroid differentiation marker acetylcholinesterase at the concentration of 50 micromol/L in the cells either treated or untreated with each erythroid differentiation inducers, whereas chebulinic acid 50 micromol/L did not change GPA protein expression in these cells significantly. When K562 cells were treated with TPA 50 microg/L for 72 h to induce megakaryocytic differentiation, the presence of chebulinic acid 50 micromol/L slightly provoked the decrease of GPA protein expression induced by TPA. Chebulinic acid did not change the TPA-induced CD61 expression at the same concentration. Chebulinic acid also reduced the mRNA levels of erythroid relative genes including gamma-globin, PBGD, NF-E2, and GATA-1 genes in K562 cells either treated or untreated with BA, whereas chebulinic acid upregulated the mRNA levels of GATA-2 transcription factor in these cells.
Chebulinic acid had inhibitory effect on erythroid differentiation likely through changing transcriptional activation of differentiation relative genes, which suggests that chebulinic acid or other tannins might influence the efficiency of some anti-tumor drugs-induced differentiation or the hematopoiesis processes.
研究诃子次酸对K562细胞红系和巨核系分化的影响。
采用联苯胺染色法评估血红蛋白合成；使用荧光标记抗体通过流式细胞术检测红系特异性糖蛋白A（GPA）蛋白和巨核系表面标志物CD61的表达；通过RT-PCR分析红系和巨核系mRNA表达。
在丁酸（BA）或血红素诱导的红系分化过程中，诃子次酸不仅以浓度依赖的方式抑制BA和血红素处理的K562细胞的血红蛋白合成，IC50分别为4 μmol/L和40 μmol/L，而且在50 μmol/L浓度下，对经每种红系分化诱导剂处理或未处理的细胞中的另一种红系分化标志物乙酰胆碱酯酶也有抑制作用，而50 μmol/L诃子次酸对这些细胞中GPA蛋白表达无明显影响。当用50 μg/L佛波酯（TPA）处理K562细胞72小时以诱导巨核系分化时，50 μmol/L诃子次酸轻微加剧了TPA诱导的GPA蛋白表达下降。相同浓度下，诃子次酸未改变TPA诱导的CD61表达。诃子次酸还降低了经BA处理或未处理的K562细胞中包括γ-珠蛋白、胆色素原脱氨酶（PBGD）、核因子E2（NF-E2）和GATA-1基因在内的红系相关基因的mRNA水平，而诃子次酸上调了这些细胞中GATA-2转录因子的mRNA水平。
诃子次酸可能通过改变分化相关基因的转录激活对红系分化产生抑制作用，这表明诃子次酸或其他单宁可能影响某些抗肿瘤药物诱导分化的效率或造血过程。
