We studied the effect of celastrol on the proliferation and apoptosis of adult T-cell leukemia (ATL) cells. After treating adult T-cell leukemia cell lines with different concentrations of celastrol, we analyzed the cell proliferation by MTT and colony formation assays. Flow cytometry was conducted to detect cell apoptosis by Annexin V-FITC/PI staining. Western blotting and dual-luciferase reporter assay were done to study the mechanism how celastrol suppressed the growth of adult T-cell leukemia cells. Celastrol could significantly inhibit the proliferation of adult T-cell leukemia cells, and induce apoptosis of ATL cells. With the increase of the concentration of celastrol, the ratio of Bax/Bcl-2 protein was up-regulated. The Caspase-3/7 protein was cleaved and activated after treatment with celastrol. Moreover, the expression of HTLV-1-encoded viral protein Tax was significantly inhibited in the celastrol treated cells. Taken together, these results indicated that celastrol effectively inhibited the proliferation of adult T-cell leukemia cells by regulating the expression of Bcl-2 family protein, and induced cell apoptosis by activating Caspase dependent pathway. In addition, celastrol could inhibit the expression of viral protein Tax. This study will provide an experimental basis for the clinical application of celastrol in the treatment of adult T-cell leukemia.
本研究旨在分析雷公藤红素对成人T 细胞白血病细胞增殖、凋亡的影响，并探讨其分子机制。使用不同浓度的雷公藤红素溶液处理多种成人T 细胞白血病细胞株，通过四唑盐比色法 (MTT)、克隆形成实验检测细胞的增殖情况；Annexin V/PI 双染检测细胞凋亡情况；最后通过Western blotting 及双荧光素酶报告基因技术探究雷公藤红素抑制成人T 细胞白血病细胞生长的调控机制。结果表明雷公藤红素能显著抑制成人T 细胞白血病细胞增殖并诱导其凋亡，随着雷公藤红素浓度的增加Bax/Bcl-2 蛋白比率明显升高，凋亡途径中Caspase-3/7 蛋白也随之被切割活化，同时病毒编码的癌蛋白Tax 的表达也明显受到抑制。以上结果表明，雷公藤红素通过调控Bcl-2家族蛋白，激活了Caspase 途径诱导细胞凋亡，并通过抑制病毒关键蛋白Tax 的表达，从而有效抑制了成人T 细胞白血病细胞的增殖。该研究为临床应用雷公藤红素治疗成人T 细胞白血病提供了实验依据。.
Keywords: Tax protein; adult T-cell leukemia; apoptosis; celastrol; proliferation.