冬凌草甲素联合地塞米松对多发性骨髓瘤U266细胞增殖及凋亡的影响

目的：探讨冬凌草甲素联合地塞米松对多发性骨髓瘤 U266细胞增殖与凋亡的影响及其相关分子机制。方法培养 U266细胞至对数生长期，分别采用高、中、低浓度的地塞米松、冬凌草甲素单独或联合处理 U266细胞，以二甲基亚砜（DMSO）处理为对照，于处理后24、48、72 h 利用 CCK-8法检测细胞增殖情况；应用 Annexin V-FITC／PI 标记及流式细胞术检测细胞凋亡；利用实时荧光定量 PCR 法检测细胞 Notch1、NF-κB／p65、bcl-2基因表达水平的变化；Westernblot 法分析 Notch1、cleavedNotch1、NF-κB／p65、bcl-2蛋白表达水平的变化。结果与对照组相比，不同剂量的药物处理组均能有效抑制 U266细胞的增殖并促进其凋亡（P＜0.05），两种药物联合应用对 U266细胞的抑制增殖和诱导凋亡具有协同作用（P＜0.05）。 U266细胞经地塞米松处理后其 NF-κB／p65、bcl-2 mRNA 和蛋白表达水平均有所下调（P＜0.05），冬凌草甲素处理组及联合处理组 U266细胞 Notch1、cleaved Notch1、NF-κB／p65、bcl-2蛋白表达水平均显著下调（P＜0.05）。结论冬凌草甲素联合地塞米松对 U266细胞增殖的抑制作用及凋亡诱导作用显著增强，其作用机制可能与抑制 Notch1信号通路有关。

Effect of dexamethasone combined with oridonin on proliferation and apoptosis of multiple myeloma cell line U266

Objective To investigate the effect of dexamethasone combined with oridonin on proliferation and apoptosis in multiple myeloma cells U266 and the related molecular mechanism. Methods Exponential phase of growth U266 cells were treated with different concentrations of oridonin combined with dexamethasone or alone. U266 cells treated by DMSO were taken as control group. The proliferation inhibitory ratios were measured by CCK-8 assay followed by 24 h, 48 h and 72 h. Apoptosis induction was assessed by using Annexin V-FITC kit. Real time PCR was used to examine the mRNA changes of Notch1, NF-κB/p65 and bcl-2. Western blot assay was applied to detect the protein expression of Notch1, cleaved Notch1, NF-κB/p65 and bcl-2. Results Compared with that in control group, proliferation in all the experimental groups was inhibited (P<0.05), and the apoptosis was promoted (P<0.05); especially the combination of dexamethasone and oridonin had a synergistic effect on the proliferation and apoptosis of U266 cells (P<0.05). The results of PCR and Western blot showed that after treatment of U266 cells with dexamethasone, the mRNA as well as their protein levels of NF-κB/p65 and bcl-2 were decreased compared with those in the control group (P<0.05). Moreover, the mRNA and protein expression of Notch1, cleaved Notch1, NF-κB/p65 and bcl-2 was obviously down-regulated in oridonin group and the combination group (P<0.05). Conclusion Combination of dexamethasone and oridonin can significantly increase the anti-tumor effect by inhibiting proliferation and inducing apoptosis of U266 cells, which may be related to the inhibition of the Notch1 pathway.