Medizinische Biochemie und Molekularbiologie, Universität des Saarlandes, Homburg, Germany.
Prostate. 2010 Feb 1;70(2):126-34. doi: 10.1002/pros.21044.
Protein kinase CK2 is a ubiquitously expressed heterotetramer consisting of two catalytic alpha/alpha' and two regulatory beta subunits. Expression of CK2 is highly elevated in tumor cells where it protects cells from apoptosis. A variety of different compounds were tested as inhibitors of protein kinase CK2 in order to find new therapy strategies. To analyze the role of p53 in the response to CK2 inhibition we used one of the most specific CK2 inhibitors available, TBB, in different prostate cancer cell lines.
We treated prostate cancer cells with the CK2 inhibitor TBB and determined its effect on CK2 activity by an in vitro phosphorylation assay and its effect on viability by an MTT assay. Furthermore, we analyzed changes in the expression of p53 and PARP cleavage by Western Blot analysis.
Inhibition of CK2 by TBB led to a decrease in cell viability and apoptosis in two cell lines which express wild-type p53 whereas two other cell lines expressing mutant or no p53 failed to show signs of apoptosis. Moreover, cell lines expressing wild-type p53 showed an increase of the amount of p53 and of its transactivation efficiency. However, down-regulation of p53 by RNAi showed that p53 is not necessary for the induction of apoptosis.
Wild-type p53 is not necessary for the induction of apoptosis by TBB in prostate cancer cells.
蛋白激酶 CK2 是一种普遍表达的异四聚体，由两个催化亚基 α/α'和两个调节亚基 β 组成。CK2 在肿瘤细胞中的表达水平显著升高，它能保护细胞免于凋亡。为了寻找新的治疗策略，人们测试了多种不同的化合物作为蛋白激酶 CK2 的抑制剂。为了分析 p53 在 CK2 抑制反应中的作用，我们使用了一种最特异的 CK2 抑制剂 TBB，在不同的前列腺癌细胞系中进行了研究。
我们用 CK2 抑制剂 TBB 处理前列腺癌细胞，通过体外磷酸化实验测定 CK2 活性的变化，通过 MTT 实验测定细胞活力的变化。此外，我们还通过 Western Blot 分析检测了 p53 和 PARP 切割的表达变化。
TBB 抑制 CK2 导致两种表达野生型 p53 的细胞系的细胞活力下降和凋亡，而另外两种表达突变型或无 p53 的细胞系则没有表现出凋亡的迹象。此外，表达野生型 p53 的细胞系显示出 p53 数量的增加和其转录激活效率的提高。然而，p53 的 RNAi 下调表明 p53 对于诱导凋亡不是必需的。
在前列腺癌细胞中，TBB 诱导凋亡并不需要野生型 p53。
