Vaccination therapy against malignant glioma using apoptosis-inducing genes

我们利用差异显示聚合酶链式反应的方法克隆了几个随着myc诱导胶质瘤细胞凋亡进程而表达水平升高或降低的基因。其中一个基因是钙调蛋白。因此，在本研究中，我们假设钙离子介导的信号转导可能参与恶性胶质瘤细胞的凋亡和免疫原性的激活，并试图通过证实这一假说来探讨其分子机制。虽然我们还没有达到最终的目标，但我们已经发现了以下几个关于细胞凋亡的分子机制的重要发现：(1)正如已报道的那样，钙调神经磷酸酶在大脑中的表达水平极高；(2)当钙调神经磷酸酶的活性增加时，蛋白酶体的活性降低；(3)当蛋白酶体的活性被抑制剂干扰时，在细胞中诱导凋亡；(4)因此，高钙调神经磷酸酶活性的细胞容易发生凋亡。这些结果可能说明，钙调神经磷酸酶高表达的海马CA1区神经元容易受到短暂性脑缺血引起的迟发性神经元死亡，尽管这些结果并不是神经细胞所特有的。胶质瘤特异性机制，如激活肿瘤免疫原性，可能位于蛋白酶体功能的下游。阐明蛋白酶体在细胞凋亡和激活肿瘤免疫原性中的作用是极其重要的，这一项目正在进行中。

We cloned several genes whose expression level increase or decrease along with the progression of myc-induced apoptosis in glioma cells by differential display PCR method. One of the genes was calmodulin. Therefore, in this study, we hypothesized that calciummediated signal transduction may be involved in apoptosis and the activation of immunogenicity in malignant glioma cells and tried to investigate their molecular mechanism by confirming the hypothesis. Although we have not reached the final goal, we have found the following several important findingsregarding molecular mechanisms of apoptosis : (1) the expression level of calcineurin is extremely high in the brain as was reported ; (2)when the activity of calcineurin increases, the activity of proteasome decreases ; (3)when the proteasome activity was perturbed by inhibitors, apoptosis is induced in the cells ; (4)as a result, the cells with high calcineurin activity are vulnerable to apoptosis. These results may elucidate that hippocampal CA1 neurons with high calcineurin expression are vulnerable to delayd neuronal death induced by transient iscemia although these results are not exclusive to neural cells. It is probable that gliomaspecific mechanisms such as sctivation of tumor-immunogenicity are located downstream of the proteasome function. It is extremely important to clarify the function of proteasome in apoptosis and activation of tumor-immunogenicity and such a project is in progress.