MEK信号通路活化在榄香烯致人源U87MG胶质瘤细胞增殖抑制及G0/G1细胞周期阻滞中的作用

Activation of MEK signaling pathway underlays the anti-proliferative and G0/G1 cell-cycle arrest effect of elemene in human U87MG glioblastoma cells

目的探讨MKK3和MKK6在榄香烯致人U87MG胶质瘤细胞增殖抑制和细胞周期阻滞中的作用。方法以不同浓度榄香烯作用于人U87MG及U251胶质瘤细胞,应用噻唑蓝(MTT)法检测细胞活性。West-ern blot检测MEK信号通路中MKK3和MKK6的总蛋白及磷酸化蛋白含量。通过转染显性负突变质粒DN-MKK3和DN-MKK6,抑制MKK3和MKK6的活性。然后分别行MTT法和流式细胞术检测榄香烯对胶质瘤细胞的增殖抑制和细胞周期阻滞作用。结果榄香烯显著抑制了人胶质瘤细胞的增殖,呈时间和浓度依赖性,并可使细胞中MKK3和MKK6的磷酸化水平上调。抑制MKK3和MKK6的活性则可显著削弱榄香烯的抗胶质瘤增殖和G0/G1细胞周期阻滞作用。结论榄香烯可以通过将胶质瘤细胞的细胞周期阻滞于G0/G1期,进而有效地抑制肿瘤细胞增殖,且MKK3和MKK6信号通路的激活在其中发挥着不可或缺的作用。

Objective To investigate the role of MKK3 and MKK6 in the anti-glioblastoma proliferation and cell-cycle arrest effect of elemene. Methods Human U87MG and U251 glioblastoma cells were treated with elemene at different drug doses. Cell viability was determined using a MTT assay. The content of p-MKK3, MKK3, p-MKK6 and MKK6 were measured by western blot analysis. UgTMG glioblastoma cells was transfected with Dominant Nega- tive-MKK3 （ DN-MKK3 ） and Dominant Negative-MKK6 （ DN-MKK6 ） to inhibit the activity of MKK3 and MKK6. Cell growth and cell cycle progression were evaluated respectively by MTT assay and flow cytometry. Results Elemene in- hibited the proliferation activity of U87MG and U251 glioblastoma cells, which showed time and dose-dependent, and increased phosphorylation of both MKK3 and MKK6 in human glioblastoma cells. In contrast,inhibition of MKK3 and MKK6 with dominant-negative plasmids reversed the antitumor effect of elemene. Conclusion Elemene can effective-ly inhibit the proliferation of glioblastoma cells through arresting them in G0/G1 phase. The activation of MKK3/6 sig-naling pathway is indispensable underlay the anti-proliferative effect of elemene in glioblastoma.