PBK/TOPK interacts with the DBD domain of tumor suppressor p53 and modulates expression of transcriptional targets including p21
PBK/TOPK interacts with the DBD domain of tumor suppressor p53 and modulates expression of transcriptional targets including p21
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DOI：
10.1038/onc.2010.275
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发表时间：
2010-10-01
期刊：
影响因子：
8
通讯作者：
Rapoport, A. P.
中科院分区：
文献类型：
--
作者：
Hu, F.;Gartenhaus, R. B.;Rapoport, A. P.
PBK/TOPK（PDZ结合激酶，T-LAK细胞源性蛋白激酶）是一种丝氨酸-苏氨酸激酶，在多种肿瘤细胞中过表达，但其在肿瘤发生中的作用尚不清楚。在这里，我们表明，通过免疫共沉淀实验和酵母双杂交分析，PBK/TOPK物理相互作用的肿瘤抑制基因p53通过其DNA结合（DBD）域在HCT 116大肠癌细胞表达野生型p53。PBK还结合到在DBD结构域中携带五个常见点突变的p53突变体。PBK-p53相互作用似乎下调p53反式激活功能，如PBK/TOPK敲低实验所示，该实验显示HCT 116细胞中关键p53靶基因和细胞周期蛋白依赖性激酶抑制剂p21的表达上调，特别是在多柔比星的遗传毒性损伤后。此外，与稳定的空载体转染的对照细胞系相比，稳定的PI 3 K/TOPK敲低细胞系（来源于HCT 116和MCF-7细胞）显示出增加的凋亡、G（2）/M停滞和较慢的生长。基因微阵列研究确定了参与细胞凋亡或细胞周期的其他p53靶基因，这些基因受PI 3 K敲低的差异调节。总之，这些数据表明，增加水平的PI 3 K/TOPK可能有助于肿瘤细胞的发展和进展，通过抑制p53功能和随之而来的细胞周期调控蛋白，如p21的减少。因此，PI 3 K/TOPK可能是一个有效的靶标，用于抑制肿瘤细胞对化疗诱导的凋亡和生长抑制的敏感性。Oncogene（2010）29，5464-5474; doi：10.1038/onc.2010.275; 2010年7月12日在线发表
PBK/TOPK (PDZ-binding kinase, T-LAK-cell-originated protein kinase) is a serine-threonine kinase that is overexpressed in a variety of tumor cells but its role in oncogenesis remains unclear. Here we show, by co-immunoprecipitation experiments and yeast two-hybrid analysis, that PBK/TOPK physically interacts with the tumor suppressor p53 through its DNA-binding (DBD) domain in HCT116 colorectal carcinoma cells that express wild-type p53. PBK also binds to p53 mutants carrying five common point mutations in the DBD domain. The PBK-p53 interaction appears to down-modulate p53 transactivation function as indicated by PBK/TOPK knockdown experiments, which show upregulated expression of the key p53 target gene and cyclin-dependent kinase inhibitor p21 in HCT116 cells, particularly after genotoxic damage from doxorubicin. Furthermore, stable PBK/TOPK knockdown cell lines (derived from HCT116 and MCF-7 cells) showed increased apoptosis, G(2)/M arrest and slower growth as compared to stable empty vector-transfected control cell lines. Gene microarray studies identified additional p53 target genes involved in apoptosis or cell cycling, which were differentially regulated by PBK knockdown. Together, these data suggest that increased levels of PBK/TOPK may contribute to tumor cell development and progression through suppression of p53 function and consequent reductions in the cell-cycle regulatory proteins such as p21. PBK/TOPK may therefore be a valid target for antineoplastic kinase inhibitors to sensitize tumor cells to chemotherapy-induced apoptosis and growth suppression. Oncogene (2010) 29, 5464-5474; doi:10.1038/onc.2010.275; published online 12 July 2010