Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, PR China.
Eur J Pharmacol. 2011 Nov 16;670(1):29-38. doi: 10.1016/j.ejphar.2011.08.045. Epub 2011 Sep 14.
The purpose of this study is to investigate the antitumor activity of a new derivative of lupeol-3β-O-succinyl-lupeol (LD9-4) and the molecular mechanism underlying cell death in human non-small cell lung cancer A549 cells. The results revealed that LD9-4 inhibited A549 cell proliferation in a time- and dose-dependent manner, with an IC(50) value of 5.78 ± 0.48 μM after cells exposed to LD9-4 for 72 h. Markers indicative of apoptosis (cell cycle arrest, phosphatidylserine externalization and Hoechst33258 staining) were uniformly negative in LD9-4 exposed cells. Interestingly, transmission electron microscope, MDC staining and LC3 level determination all confirmed that autophagy was induced in LD9-4 treated A549 cells. Furthermore, we found that LD9-4-induced autophagy in A549 cells was associated with the increase of intracellular reactive oxygen species and the decrease of phosphorylated mTOR and p70S6K levels. In the meanwhile, both mRNA and protein levels of Beclin 1 were up-regulated in a time-dependent manner. Our data suggest that autophagy is induced by LD9-4 in A549 cells, and the accumulating reactive oxygen species, up-regulation of Beclin 1 and inhibition of the mTOR signaling pathway are involved in this process.
本研究旨在探讨新型羽扇豆醇-3β-O-琥珀酰基-羽扇豆醇（LD9-4）衍生物在人非小细胞肺癌 A549 细胞中的抗肿瘤活性及其诱导细胞死亡的分子机制。结果表明，LD9-4 呈时间和剂量依赖性抑制 A549 细胞增殖，细胞暴露于 LD9-4 72 h 后，IC50 值为 5.78±0.48 μM。凋亡标志物（细胞周期阻滞、磷脂酰丝氨酸外翻和 Hoechst33258 染色）在 LD9-4 暴露细胞中均呈阴性。有趣的是，透射电镜、MDC 染色和 LC3 水平测定均证实 LD9-4 处理的 A549 细胞中发生了自噬。此外，我们发现 LD9-4 诱导的 A549 细胞自噬与细胞内活性氧的增加以及磷酸化 mTOR 和 p70S6K 水平的降低有关。同时，Beclin 1 的 mRNA 和蛋白水平均呈时间依赖性上调。我们的数据表明，LD9-4 诱导 A549 细胞发生自噬，而活性氧的积累、Beclin 1 的上调以及 mTOR 信号通路的抑制均参与了这一过程。
