Jin Limin, Miao Jinhong, Liu Yanjin, Li Xingdan, Jie Yaqiong, Niu Qianyun, Han Xinguang
Department of Oral & Maxillofacial Surgery, The First Affiliated Hospital, Zhengzhou University, China.
Department of Nursing Management,The First Affiliated Hospital, Zhengzhou University, China.
Biomed Pharmacother. 2017 Jan;85:287-295. doi: 10.1016/j.biopha.2016.11.023. Epub 2016 Nov 23.
The present study is aimed to investigate the apoptosis-inducing effect of icaritin in human oral squamous cell carcinoma (OSCC) cells and the associated mechanisms.
KB and SCC9 cell lines were used as model cell lines. Effect of icaritin on apoptosis was analyzed by flow cytometry. The effect of icaritin on mitochondrial apoptotic pathway was demonstrated by loss of mitochondrial membrane potential and release of cytocrome C from mitochondria. MiR-124 mimic and miR-124 inhibitor were used to manipulate the expression of miR-124 in OSCC cells. SiRNA targeting Sp1 and DNMT1 as well as Sp1 and DNMT1 overexpressing vector were utilized to confirm their roles in the apoptosis-inducing effect of icaritin in OSCC cells. Activation of relevant signaling pathway by icaritin and effect of icaritin on expression of targeting molecules were determined by western blots or qRT-PCR.
Our results showed that icaritin inhibited tumor cell viability in a dose- and time-dependent manner, and induced cell apoptosis via intrinsic mitochondrial pathway by upregulating miR-124. Moreover, our results showed that the icaritin exerted regulatory effect on miR-124 through suppressing Sp1/DNMT1 signaling.
Our data provide the first experimental evidence that icaritin induces mitochondrial apoptosis in OSCC cells by upregulating miR-124 and suggest a new mechanism to explain its anti-tumor effects.
本研究旨在探讨淫羊藿素对人口腔鳞状细胞癌（OSCC）细胞的凋亡诱导作用及其相关机制。
以KB和SCC9细胞系作为模型细胞系。采用流式细胞术分析淫羊藿素对细胞凋亡的影响。通过线粒体膜电位丧失和细胞色素C从线粒体释放来证明淫羊藿素对线粒体凋亡途径的影响。使用miR-124模拟物和miR-124抑制剂来调控OSCC细胞中miR-124的表达。利用靶向Sp1和DNMT1的小干扰RNA（siRNA）以及Sp1和DNMT1过表达载体来证实它们在淫羊藿素诱导OSCC细胞凋亡作用中的角色。通过蛋白质免疫印迹法（western blots）或实时定量聚合酶链反应（qRT-PCR）来确定淫羊藿素对相关信号通路的激活作用以及淫羊藿素对靶向分子表达的影响。
我们的结果表明，淫羊藿素以剂量和时间依赖性方式抑制肿瘤细胞活力，并通过上调miR-124经内源性线粒体途径诱导细胞凋亡。此外，我们的结果表明，淫羊藿素通过抑制Sp1/DNMT1信号传导对miR-124发挥调控作用。
我们的数据提供了首个实验证据，即淫羊藿素通过上调miR-124诱导OSCC细胞发生线粒体凋亡，并提示了一种新机制来解释其抗肿瘤作用。
