Functional consequences of the first reported mutations of the proto-oncogene PTTG1IP/PBF.
Functional consequences of the first reported mutations of the proto-oncogene PTTG1IP/PBF.
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DOI：
10.1530/erc-16-0340
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发表时间：
2017-09
影响因子：
3.9
通讯作者：
McCabe CJ
中科院分区：
文献类型：
--
作者：
Imruetaicharoenchoke W;Fletcher A;Lu W;Watkins RJ;Modasia B;Poole VL;Nieto HR;Thompson RJ;Boelaert K;Read ML;Smith VE;McCabe CJ
肿瘤转化基因1结合因子（PTTG 1 IP; PBF）是一种多功能糖蛋白，在多种肿瘤中过度表达，与肿瘤预后不良显著相关，如早期肿瘤复发、远处转移、壁外血管浸润和疾病特异性生存率降低。PBF转化NIH 3 T3成纤维细胞并在裸鼠中诱导肿瘤，而具有转基因甲状腺PBF表达的小鼠显示增生和大滤泡病变。我们的假设，PBF成为一个癌基因纯粹通过增加表达已受到挑战，最近的报告中的突变PBF在癌症体细胞突变目录（COSMIC）数据库。因此，我们试图确定人类癌症中的前10个PBF错义取代是否可能是致癌的。茴香霉素半衰期研究显示，与野生型（WT）PBF相比，大多数突变与蛋白质稳定性降低相关。增殖测定将我们的兴趣缩小到两个显著改变细胞周转的突变事件：C51 R和R140 W。C51 R主要定位于内质网，R140 W定位于高尔基体。C51 R和R140 W都失去了诱导细胞迁移的能力，并显著降低了细胞侵袭。集落形成和软琼脂试验表明，与WT PBF相反，两种突变体都不能引起显着的集落形成或锚定非依赖性生长。然而，C51 R和R140 W保留了抑制放射性碘摄取的能力，这是PBF的功能标志。我们的数据揭示了PBF功能的新见解，并证实，而不是致癌的，PBF的突变可能是乘客的影响，与PBF的过度表达更重要的人类癌症的病因学事件。
Pituitary tumor-transforming gene 1-binding factor (PTTG1IP; PBF) is a multifunctional glycoprotein, which is overexpressed in a wide range of tumours, and significantly associated with poorer oncological outcomes, such as early tumour recurrence, distant metastasis, extramural vascular invasion and decreased disease-specific survival. PBF transforms NIH 3T3 fibroblasts and induces tumours in nude mice, while mice harbouring transgenic thyroidal PBF expression show hyperplasia and macrofollicular lesions. Our assumption that PBF becomes an oncogene purely through increased expression has been challenged by the recent report of mutations in PBF within the Catalogue of Somatic Mutations in Cancer (COSMIC) database. We therefore sought to determine whether the first 10 PBF missense substitutions in human cancer might be oncogenic. Anisomycin half-life studies revealed that most mutations were associated with reduced protein stability compared to wild-type (WT) PBF. Proliferation assays narrowed our interest to two mutational events which significantly altered cell turnover: C51R and R140W. C51R was mainly confined to the endoplasmic reticulum while R140W was apparent in the Golgi apparatus. Both C51R and R140W lost the capacity to induce cellular migration and significantly reduced cell invasion. Colony formation and soft agar assays demonstrated that, in contrast to WT PBF, both mutants were unable to elicit significant colony formation or anchorage-independent growth. However, C51R and R140W retained the ability to repress radioiodide uptake, a functional hallmark of PBF. Our data reveal new insight into PBF function and confirm that, rather than being oncogenic, mutations in PBF are likely to be passenger effects, with overexpression of PBF the more important aetiological event in human cancer.