摘要目的：探讨同时抑制 mTORC1激酶和 GSK-3β激酶活性对黑素瘤细胞4EBP1的磷酸化、帽子依赖翻译、细胞存活和凋亡的影响。方法分别采用二甲基亚砜（DMSO 组）、5 nmol/L 依维莫司（依维莫司组）、10μmol/L AR-A014418（AR-A014418组）、5 nmol/L 依维莫司联合10μmol/L AR-A014418（联合处理组）处理A375细胞，Western 印迹法检测4EBP1的磷酸化和生存素蛋白的表达，m7GTP pull-down 实验检测 eIF4E 和eIF4G 的相互作用，CCK8法和流式细胞仪分别检测 A375细胞的增殖和凋亡。结果依维莫司和 AR-A014418对4EBP1磷酸化和生存素蛋白表达均有一定的抑制作用，两组 p4EBP1-65分别为0.74±0.05和0.62±0.06，生存素蛋白分别为0.71±0.06和0.58±0.07，与 DMSO 组（分别为1.00±0.07和1.00±0.06）相比，均 P ＜0.001，且联合处理组对4EBP1磷酸化（0.14±0.04）和生存素蛋白表达（0.09±0.05）的抑制更为显著。m7GTP pull-down实验显示，依维莫司组（0.72±0.04）、AR-A014418组（0.67±0.05）、联合处理组（0.12±0.05）eIF4G 相对值均低于 DMSO 组（1.00±0.06），而4EBP1相对值均高于 DMSO 组（分别为1.98±0.16、2.32±0.17、7.58±0.25、1.00±0.08），且联合处理组 eIF4G 降低和4EBP1增加最为显著。培养24 h 时，与 DMSO 组相比，依维莫司、AR-A014418、依维莫司联合 AR-A014418均对 A375细胞增殖有抑制作用（后3组抑制率分别为18.5%±1.3%、19.8%±1.8%、61.2%±2.1%），且联合处理组的抑制作用最为显著；培养48 h 时，依维莫司和 AR-A014418对A375细胞增殖的抑制显示相同的趋势，且其抑制作用随时间的延长而增强。流式细胞仪检测显示，依维莫司和AR-A014418单独处理 A375细胞24 h 对其凋亡有一定的促进作用（凋亡率分别为14.28%±2.18%、14.57%±2.35%），联合处理时细胞凋亡更为显著，凋亡率为55.18%±6.27%。结论联合使用依维莫司和 AR-A014418显著抑制 A375细胞中4EBP1的磷酸化，进而抑制 eIF4F 蛋白复合物的形成，从而抑制帽子依赖的翻译，促进黑素瘤细胞的凋亡。

abstractsObjective To evaluate effects of simultaneous inhibition of mammalian target of rapamycin complex 1(mTORC1)kinase and glycogen synthase kinase-3β(GSK-3β)on phosphorylation of 4E-binding protein-1(4EBP1), cap-dependent translation, as well as survival and apoptosis of melanoma cells. Methods Cultured A375 cells were classified into several groups to be treated with dimethyl sulfoxide (DMSO group), the mTORC1 kinase inhibitor everolimus at a concentration of 5 nmol/L (everolimus group), the GSK-3β kinase inhibitor AR-A014418 at a concentration of 10 μmol/L (AR-A014418 group), or 5 nmol/L everolimus and 10 μmol/L AR-A014418(combined treatment group). After additional culture, Western-blot analysis was performed to measure protein expressions of phosphorylated 4EBP1 (p4EBP1)and survivin in A375 cells, m7GTP pull down assay to estimate interaction between eukaryotic initiation factor-4E (eIF4E)and eIF4G, cell counting kit 8 (CCK8)assay to evaluate cell proliferation, and flow cytometry to detect cell apoptosis. Results Both everolimus and AR-A014418 had inhibitory effects on 4EBP1 phosphorylation and survivin expression. The expressions of p4EBP1-65 and survivin were both significantly decreased in the everolimus group (0.74 ± 0.05 and 0.71 ± 0.06 respectively), AR-A014418 group (0.62 ± 0.06 and 0.58 ± 0.07 respectively)and combined treatment group (0.14 ± 0.04 and 0.09 ± 0.05 respectively)compared with the DMSO group (1.00 ± 0.07 and 1.00 ± 0.06, respectively, all P < 0.001), with the most significant decrease observed in the combined&nbsp;treatment group. As m7GTP pull-down assay showed, the everolimus group, AR-A014418 group and combined treatment group all showed significantly lower relative expression levels of eIF4G(0.72 ± 0.04, 0.67 ± 0.05 and 0.12 ± 0.05 vs. 1.00 ± 0.06, all P < 0.001), but significantly higher relative expression levels of 4EBP1 (1.98 ± 0.16, 2.32 ± 0.17 and 7.58 ± 0.25 vs. 1.00 ± 0.08, all P < 0.001)than the DMSO group, and the combined treatment group showed the lowest eIF4G expression but highest 4EBP1 expression. After 24-hour culture, the proliferation of A375 cells was inhibited by 18.5% ± 1.3% in the everolimus group, 19.8% ± 1.8% in the AR-A014418 group, and 61.2% ± 2.1% in the combined treatment group compared with the DMSO group, with the strongest inhibition noted in the combined treatment group. The inhibitory effects of everolimus and AR-A014418 on cell proliferation increased over time, and showed the same trend at 48 hours. Flow cytometry showed that the apoptosis of A375 cells was accelerated by the 24-hour treatments with everolimus and AR-A014418 alone or in combination, with the apoptosis rate being 14.28% ± 2.18%, 14.57% ± 2.35% and 55.18% ± 6.27% in the everolimus group, AR-A014418 group and combined treatment group respectively, and the combined treatment showed the strongest accelerating effect. Conclusion The combined treatment with everolimus and AR-A014418 can evidently inhibit 4EBP1 phosphorylation and eIF4F complex formation in A375 cells, which then suppress cap-dependent translation and promote apoptosis of melanoma cells.