Regulation of class II β-tubulin expression by tumor suppressor p53 protein in mouse melanoma cells in response to Vinca alkaloid
Regulation of class II β-tubulin expression by tumor suppressor p53 protein in mouse melanoma cells in response to Vinca alkaloid
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DOI：
10.1158/1541-7786.mcr-05-0183
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发表时间：
2006-04-01
影响因子：
5.2
通讯作者：
Yagasaki, K
中科院分区：
文献类型：
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作者：
Arai, K;Matsumoto, Y;Yagasaki, K
抗微管药物对肿瘤的持续暴露通常导致出现具有改变的几种β-微管蛋白同种型表达的耐药肿瘤细胞。我们发现，在小鼠B16 F10黑色素瘤细胞中，通过改变肿瘤抑制基因p53蛋白，海兰生物碱增强了II类β-微管蛋白同种型（mTUBB 2）的表达。奥曲肽处理刺激mTUBB 2 mRNA表达增加，并促进该同种型在细胞核周围的积累。瞬时转染试验采用报告构建体，连同定点诱变研究，表明在第一内含子中发现的p53结合位点是mTUBB 2表达的关键区域。电泳迁移率改变实验和相关抗体超迁移实验表明，长春新碱促进p53蛋白从结合位点释放。此外，外源性诱导TAp 63 γ（p51 A）（p53的同源物）消除了长春新碱对mTUBB 2表达的影响。这些结果表明，p53蛋白可能作为mTUBB 2表达的抑制剂，长春新碱介导的p53结合抑制导致mTUBB 2表达增强。这种现象可能与生物碱诱导的耐药肿瘤细胞的出现有关，并可能参与决定这些细胞的命运。
The continuous exposure of antimicrotubule drugs to tumors often results in the emergence of drug-resistant tumor cells with altered expression of several beta-tubulin isotypes. We found that Vinca alkaloid enhanced expression of class II beta-tubulin isotype (mTUBB2) in mouse B16F10 melanoma cells via alteration of the tumor suppressor p53 protein. Vincristine treatment stimulated an increase in mTUBB2 mRNA expression and promoted accumulation of this isotype around the nuclei. Transient transfection assays employing a reporter construct, together with site-directed mutagenesis studies, suggested that the p53-binding site found in the first intron was a critical region for mTUBB2 expression. Electrophoretic mobility shift assay and associated antibody supershift experiments showed that vincristine promoted release of p53 protein from the binding site. In addition, exogenous Induction of TAp63 gamma (p51A), a homologue of p53, canceled the effect of vincristine on mTUBB2 expression. These results suggest that p53 protein may function as a suppressor of mTUBB2 expression and vincristine-mediated inhibition of p53 binding results in enhanced mTUBB2 expression. This phenomenon could be related with the emergence of drug-resistant tumor cells induced by Vinca alkaloid and may participate in determining the fate of these cells.