榄香烯致Raf/MEK/ERK通路中关键蛋白错误折叠诱导脑胶质瘤凋亡机制的研究

β-Elemene, an active component of herb medicine Curcuma wenyujin, has been shown to antagonize glioblastoma cells by inducing apoptosis. However, how β-Elemene induces apoptosis of these cells remains unclear. β-Elemene is an alkylating agent, with the chemical formula 1-methyl, 1-ethenyl, 2-isopropenyl, 4-isopropenyl cyclohexane. Alkylating agents are highly reactive chemicals that introduce alkyl radicals into biologically active molecules and thereby prevent their proper functioning. They can cause protein misfolding, and many of them are used as antineoplastic agents..In our preliminary experiments, we found that β-Elemene decreased the levels of phosphorylated ERK1/2 and Bcl-2 and disrupted the formation of the Hsp90/Raf-1 complex. In the control group C6 glioblastoma cells (The concentration of β-Elemene is zero), the constitutive activation of Raf/MEK/ERK pathway was observed. Ras activity is upregulated in the majority of cases of human glioblastoma multiforme. Furthermore, the level of phosphorylated ERK, a downstream effector of Ras, is also increased. Constitutive activation of the Ras/MAPK pathway is functionally important for glioblastoma cell proliferation..There are some "key" proteins (Grb2, mSos, Shc, 14-3-3, Hsp90, et al.) in the Raf/MEK/ERK pathway which are significantly important for this pathway's signal transduction. Such proteins' function is intensively dependent on their conserved spatial conformation..So in this study, we hypothesize and testify if β-Elemene could cause these proteins' misfolding, inhibit the constitutive activation of Ras/MAPK pathway as well as downstream signaling targets such as Bcl-2, thereby lead to apoptosis of glioblastoma cells.

榄香烯主要成分烷基化试剂β-榄香烯具有诱导蛋白错误折叠的特性，临床和前期基础研究发现其有抗胶质瘤作用，但机制和作用靶点不详。预实验榄香烯下调p-ERK1/2及Bcl-2并阻碍Hsp90/Raf-1分子复合体形成；且榄香烯浓度为0时，即正常C6细胞中Raf/MEK/ERK通路活性最高（呈组成性激活）。人类癌基因中Ras基因突变率最高，突变后可引起Raf/MEK/ERK通路组成性激活而导致癌基因Bcl-2过表达，是胶质瘤细胞赖以生存的基础。Raf/MEK/ERK通路中某些蛋白质对该通路信号的转导至关重要，而这些蛋白功能的发挥高度依赖于其自身空间结构。围绕检验榄香烯致Raf/MEK/ERK通路中致某些关键蛋白(Grb2、mSos、Shc、14-3-3、hsp90等)错误折叠、构象改变、功能丧失从而抑制该通路的组成性激活、下调癌基因Bcl-2、促使细胞凋亡的抗胶质瘤靶点机制研究为本课题创新之处。

胶质瘤是颅内最常见的原发性中枢神经系统肿瘤，约占所有颅内原发肿瘤的一半。具有高度侵袭性，对常规化疗药物极不敏感，也很难被神经外科显微手术完全切除等临床特性。榄香烯(Elemene)是从传统中草药姜科植物温郁金(温莪术)中提取获得的萜烯类化合物，以β-榄香烯为主要成分,并含有少量γ-和δ-榄香烯及其它萜类化合物。榄香烯通过实验研究和临床试验已于1994年作为国家二类抗肿瘤新药上市应用。榄香烯主要成分烷基化试剂β-榄香烯具有诱导蛋白错误折叠的特性，临床和前期基础研究发现其有抗胶质瘤作用，但机制和作用靶点不详。. 本课题主要研究榄香烯对胶质瘤细胞生长及凋亡方面的具体作用。首先，通过预实验榄香烯下调p-ERK1/2及Bcl-2并阻碍Hsp90/Raf-1分子复合体形成；且榄香烯浓度为0时，即正常C6细胞中Raf/MEK/ERK通路活性最高（呈组成性激活）。人类癌基因中Ras基因突变率最高，突变后可引起Raf/MEK/ERK通路组成性激活而导致癌基因Bcl-2过表达，是胶质瘤细胞赖以生存的基础。Raf/MEK/ERK通路中某些蛋白质对该通路信号的转导至关重要，而这些蛋白功能的发挥高度依赖于其自身空间结构。围绕检验榄香烯致Raf/MEK/ERK通路中致某些关键蛋白(Grb2、mSos、Shc、14-3-3、hsp90等)错误折叠、构象改变、功能丧失从而抑制该通路的组成性激活、下调癌基因Bcl-2、促使细胞凋亡的抗胶质瘤靶点机制研究为本课题创新之处。其次，榄香烯增强了胶质瘤细胞中放疗作用诱导的DNA损伤，并通过抑制ATM通路,下调其相关蛋白ATM,H2AX,增强了胶质瘤细胞的放疗增敏作用。 最后，榄香烯通过抑制EGFR通路，增强了分子靶向药物吉非替尼在胶质瘤治疗中的应用，抑制肿瘤细胞生长的同时，有效地诱导了细胞的凋亡及自噬的发生。. 本课题首次发现了榄香烯与胶质瘤细胞相关的ATM,EGFR等新通路的研究，并充分证明了放疗与化疗相结合，及榄香烯与分子靶向药物协同作用等有效治疗方案，这些新的治疗策略有望在胶质瘤的临床治疗中发挥重要作用。