BU Oncology, Nerviano Medical Sciences srl, 20014 Nerviano, Italy.
Anticancer Res. 2010 Dec;30(12):4973-85.
Polo-like kinase 1 (PLK1) is the master regulator of mitosis and a target for anticancer therapy. To develop a marker of PLK1 activity in cells and tumour tissues, this study focused on translational controlled tumour protein (TCTP) and identified serine 46 as a site phosphorylated by PLK1 in vitro. Using an antibody raised against phospho-TCTP-Ser46, it was demonstrated that phosphorylation at this site correlates with PLK1 level and kinase activity in cells. Moreover, PLK1 depletion by siRNA or inactivation by specific inhibitors caused a correspondent decrease in phospho-TCTP-Ser46 signal validating this site as a direct marker of PLK1. Using this marker, the study characterized PLK1 inhibitors in cells by setting up a high-content assay and finally immunohistochemical assay suitable for following inhibitor activity in preclinical tumour models and possibly in clinical studies was developed.
丝氨酸/苏氨酸蛋白激酶 1（PLK1）是有丝分裂的主要调节因子，也是抗癌治疗的靶点。为了在细胞和肿瘤组织中开发 PLK1 活性的标志物，本研究专注于翻译控制肿瘤蛋白（TCTP），并鉴定出丝氨酸 46 是 PLK1 在体外磷酸化的位点。使用针对磷酸化 TCTP-Ser46 的抗体，证明该位点的磷酸化与细胞中 PLK1 水平和激酶活性相关。此外，通过 siRNA 或特异性抑制剂使 PLK1 失活会导致磷酸化 TCTP-Ser46 信号相应减少，验证了该位点是 PLK1 的直接标志物。使用该标志物，通过建立高内涵测定法，本研究在细胞中对 PLK1 抑制剂进行了表征，最终开发出适合在临床前肿瘤模型中以及可能在临床研究中检测抑制剂活性的免疫组织化学测定法。
