Mfn2在环孢素A诱导HeLa细胞生长停滞中的作用

 目的: 探讨环孢素A (TSA) 对HeLa细胞中线粒体融合蛋白 2(Mfn2)表达水平极其下游通路的影响。方法: 运用不同浓度的TSA处理HeLa细胞,分别检测细胞增殖、细胞凋亡以及细胞的周期改变;Western blot检测Ras、p-Raf、Raf、p-ERK、ERK、p-Akt、Akt和Mfn2的蛋白水平;real-time PCR检测Mfn2 mRNA的表达水平;用免疫共沉淀法检测Mfn2与Ras结合的水平。将HeLa细胞过表达Mfn2后,观察上述指标的改变。结果: TSA对HeLa的抑制作用呈剂量依赖和时间依赖的特点。HeLa细胞经TSA处理后,Mfn2的mRNA和蛋白表达水平均显著增高,Mfn2与Ras的结合升高,Raf和ERK的磷酸化水平降低。过表达Mfn2抑制了Ras-Raf-ERK通路并诱导了HeLa细胞的生长阻滞,但对细胞的凋亡水平影响较小。结论: Mfn2参与了TSA诱导的HeLa细胞生长阻滞,其效应可能是通过抑制Ras-Raf-ERK通路实现的。

Role of Mfn2 in mediating trichostatin A-induced growth arrest in HeLa cells

AIM: To investigate the roles of mitofusin 2 (Mfn2) in mediating trichostatin A (TSA)-induced growth arrest and the underlying mechanism. METHODS: After treating with different doses of TSA or over-expression of Mfn2, the proliferation, apoptosis and cell cycle of HeLa cells were analyzed. The protein levels of Ras, p-Raf, Raf, p-ERK, ERK, p-Akt, Akt and Mfn2 were determined by Western blot. The mRNA expression of Mfn2 was detected by real-time PCR. The interaction between Mfn2 and Ras was probed by co-immunoprecipitation. RESULTS: TSA inhibited cell proliferation by inducing apoptosis and a cell-cycle arrest at G₂/M phase in a dose and time dependent manner in the HeLa cells. TSA induced up-regulation of Mfn2 at mRNA and protein levels, improved interaction between Mfn2 and Ras and decreased the phosphorylation levels of Raf and ERK. However, Mfn2 over-expression hardly caused cell apoptosis, yet it resulted in severe growth arrest by inhibiting Ras-Raf-ERK pathway in the HeLa cells. CONCLUSION: TSA might trigger HeLa cell arrest by increasing Mfn2 expression and thus inhibiting the activity of Ras-Raf-ERK pathway.