Abstract Introduction Despite the significant developments occurring in the treatment of cancer, multiple myeloma remains the second haematological deadly disease. The aim of this study was to investigate the antiproliferative and apoptotic activities of Olea europaea L. cv Chetoui leaf and stem extracts (OLE and OSE) on human myeloma cells, given that plant compounds provide antitumor drugs. Methods Anti-cancer activity was tested on U266 human multiple myeloma cell line using MTT and trypan blue assays. Cell cycle analysis, cell death mechanism, mitochondrial membrane potential levels and caspases activities were assessed in U266 cells using flow cytometry. The nuclear morphology of U266 cells was observed using Hoechst 33342 using fluorescent microscopy. Results Our data revealed that treatment with OLE and OSE induced anti-proliferative effects on U266 myeloma cells in dose and time dependent manner. The IC50 of OLE and OSE were 55 and 35 μg/mL, respectively after 48 h of exposure. Interestingly, cell cycle analysis showed significant decrease of U266 cells in G1 phase related to significant increase in sub-G1 population after 24 h of extract treatment. Moreover, OLE and OSE significantly induced apoptosis in U266 cell line after 24 h of treatment by inducing mitochondria dysfunctions and caspase 3/7 expression. Conclusion To our knowledge this is the first paper to be conducted on olive stem extract. Our study showed that OLE and OSE had potent anti-multiple myeloma properties. This work may form the basis for further investigation on olive extracts as potential therapeutic agent on multiple myeloma.

中文翻译：

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Olea europaea L. cv. Chetoui 叶和茎的水甲醇提取物通过人多发性骨髓瘤细胞上的半胱天冬酶信号抑制增殖并促进细胞凋亡

摘要 引言 尽管癌症治疗取得了重大进展，但多发性骨髓瘤仍然是血液学上的第二种致命疾病。鉴于植物化合物提供抗肿瘤药物，本研究的目的是调查 Olea europaea L. cv Chetoui 叶和茎提取物（OLE 和 OSE）对人骨髓瘤细胞的抗增殖和凋亡活性。方法使用MTT和台盼蓝测定对U266人多发性骨髓瘤细胞系测试抗癌活性。使用流式细胞术在 U266 细胞中评估细胞周期分析、细胞死亡机制、线粒体膜电位水平和半胱天冬酶活性。使用 Hoechst 33342 荧光显微镜观察 U266 细胞的核形态。结果我们的数据显示用OLE和OSE治疗以剂量和时间依赖性方式诱导对U266骨髓瘤细胞的抗增殖作用。接触 48 小时后，OLE 和 OSE 的 IC50 分别为 55 和 35 μg/mL。有趣的是，细胞周期分析显示 G1 期 U266 细胞显着减少，这与提取物处理 24 小时后亚 G1 群体的显着增加有关。此外，OLE 和 OSE 通过诱导线粒体功能障碍和 caspase 3/7 表达，在治疗 24 小时后显着诱导 U266 细胞系凋亡。结论 据我们所知，这是第一篇关于橄榄茎提取物的论文。我们的研究表明 OLE 和 OSE 具有有效的抗多发性骨髓瘤特性。