BACKGROUND Arnidiol is a pentacyclic triterpene diol that has multiple pharmacological activities. However, the apoptotic activities of arnidiol in human cancer cells have not yet been explored, nor has the mechanism by which arnidiol induces apoptosis been examined in depth. METHODS MDA-MB-231 cells and xenografted mice were treated with arnidiol. Mitochondrial fission and apoptosis were determined by immunofluorescence, flow cytometry and related molecular biological techniques. The interaction and colocalization of cofilin and Drp1 was determined by immunoprecipitation and immunofluorescence assays. RESULTS Arnidiol induces mitochondrial fission and apoptosis through mitochondrial translocation of Drp1 and cofilin. Importantly, the interaction of Drp1 and cofilin in mitochondria is involved in arnidiol-induced mitochondrial fission and apoptosis. Knockdown of either Drp1 or cofilin abrogated arnidiol-induced mitochondrial translocation, interaction of Drp1 and cofilin, mitochondrial fission and apoptosis. Only dephosphorylated Drp1 (Ser637) and cofilin (Ser3) were translocated to the mitochondria. Mutants of Drp1 S637A and cofilin S3A, which mimic the dephosphorylated forms, enhanced mitochondrial fission and apoptosis induced by arnidiol, whereas mutants of Drp1 S637D and cofilin S3E, which mimic the phosphorylated forms, suppressed mitochondrial fission and apoptosis induced by arnidiol. A mechanistic study revealed that ROCK1 activation plays an important role in the arnidiol-mediated Drp1 and cofilin dephosphorylation and mitochondrial translocation, mitochondrial fission, and apoptosis. CONCLUSIONS Our data reveal a novel role of both Drp1 and cofilin in the regulation of mitochondrial fission and apoptosis and suggest that arnidiol could be developed as a potential agent for the treatment of human cancer.

中文翻译：

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ROCK1激活介导的Drp1和cofilin的线粒体易位是阿糖醇诱导的线粒体裂变和凋亡所必需的。

背景技术炔二醇是具有多种药理活性的五环三萜二醇。但是，尚未研究阿糖二醇在人癌细胞中的凋亡活性，也没有深入研究阿糖二醇诱导凋亡的机制。方法用炔诺醇处理MDA-MB-231细胞和异种移植小鼠。通过免疫荧光，流式细胞术和相关的分子生物学技术确定线粒体的分裂和凋亡。通过免疫沉淀和免疫荧光测定法确定cofilin和Drp1的相互作用和共定位。结果炔诺醇通过Drp1和cofilin的线粒体易位诱导线粒体裂变和凋亡。重要的，线粒体中Drp1和cofilin的相互作用与阿糖醇诱导的线粒体裂变和凋亡有关。击倒Drp1或cofilin废除阿尼二醇引起的线粒体易位，Drp1与cofilin的相互作用，线粒体裂变和凋亡。只有去磷酸化的Drp1（Ser637）和cofilin（Ser3）转移到线粒体。模仿去磷酸化形式的Drp1 S637A和cofilin S3A突变体增强了阿里尼醇诱导的线粒体裂变和凋亡，而模仿磷酸化形式的Drp1 S637D和cofilin S3E突变体抑制了阿糖醇诱导的线粒体分裂和凋亡。一项机理研究表明，ROCK1激活在戊二醇介导的Drp1和cofilin去磷酸化以及线粒体易位中起着重要作用，线粒体裂变和凋亡。结论我们的数据揭示了Drp1和cofilin在线粒体裂变和凋亡调控中的新作用，并暗示了可以将阿糖二醇开发为治疗人类癌症的潜在药物。