KIBRA通过抑制RASSF1A获得致癌活性。

KIBRA attains oncogenic activity by repressing RASSF1A.

作者信息

Arivazhagan Lakshmi, Surabhi Rohan Prasad, Kanakarajan Archana, Sundaram Sandhya, Pitani Ravi Shankar, Mudduwa Lakmini, Kremerskothen Joachim, Venkatraman Ganesh, Rayala Suresh K

机构信息

Department of Biotechnology, Indian Institute of Technology Madras (IITM), Chennai 600036, India.

Pathology, Sri Ramachandra University, Porur, Chennai 600116, India.

出版信息

Br J Cancer. 2017 Jun 29;117(4):553-62. doi: 10.1038/bjc.2017.192.

DOI:10.1038/bjc.2017.192

PMID:28664913

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5558681/

Abstract

BACKGROUND

KIBRA-initially identified as a neuronal associated protein is now shown to be functionally associated with other tissue types as well. KIBRA interacts with dyenin light chain 1 and this interaction is essential for oestrogen receptor transactivation in breast cancer cells. KIBRA as a substrate of Cdk1, Aurora kinase and ERK plays an important role in regulating cell cycle, cell proliferation and migration. Despite these evidences, the exact role of KIBRA in cancer progression is not known.

METHODS

We studied the expression of KIBRA in breast tissues and breast cancer cell lines by western blotting, immunohistochemisry (IHC) and RT-PCR. Stable over expression and knockdown clones were generated to study the transforming properties of KIBRA by conventional assays. Xenograft studies were performed in nude mice to study the in vivo tumourigenic efficacy of KIBRA. qPCR array was performed to understand the molecular mechanism behind oncogenic activity of KIBRA.

RESULTS

Our results showed that KIBRA is upregulated in breast cancer cells and in malignant human breast tumours by both western blotting and IHC. Interestingly, we found that KIBRA expression level goes up with increase in breast cancer progression in well-established MCF10A model system. Further, results from stable overexpression clones of KIBRA in fibroblasts (Rat-1) and epithelial breast cancer cells (ZR75) and lentiviral short hairpin RNA-mediated knockdown (KD) clones of KIBRA in ZR75 showed increase in transforming properties with KIBRA overexpression and vice-versa. Results also showed that fibroblasts stably overexpressing KIBRA showed increased tumourigenic potential in nude mice. By adopting a quantitative PCR array-based approach, we identified RASSF1A, a tumour suppressor, as a transcriptional target of KIBRA.

CONCLUSIONS

This is the first study to demonstrate the in vivo tumourigenic property of KIBRA in a nude mouse model and also unravel the underlying molecular mechanism of KIBRA-mediated transformation via repression of RASSF1A.British Journal of Cancer advance online publication, 29 June 2017; doi:10.1038/bjc.2017.192 www.bjcancer.com.

摘要

背景

KIBRA最初被鉴定为一种神经元相关蛋白，现在发现它在功能上也与其他组织类型有关。KIBRA与动力蛋白轻链1相互作用，这种相互作用对于乳腺癌细胞中雌激素受体的反式激活至关重要。KIBRA作为细胞周期蛋白依赖性激酶1、极光激酶和细胞外信号调节激酶的底物，在调节细胞周期、细胞增殖和迁移中起重要作用。尽管有这些证据，但KIBRA在癌症进展中的确切作用尚不清楚。

方法

我们通过蛋白质免疫印迹法、免疫组织化学（IHC）和逆转录聚合酶链反应（RT-PCR）研究了KIBRA在乳腺组织和乳腺癌细胞系中的表达。通过传统检测方法构建稳定过表达和敲低克隆，以研究KIBRA的转化特性。在裸鼠中进行异种移植研究，以研究KIBRA在体内的致瘤效果。进行定量PCR芯片分析，以了解KIBRA致癌活性背后的分子机制。

结果

我们的结果表明，通过蛋白质免疫印迹法和免疫组织化学均发现KIBRA在乳腺癌细胞和恶性人乳腺肿瘤中上调。有趣的是，我们发现在成熟的MCF10A模型系统中，KIBRA表达水平随着乳腺癌进展而升高。此外，KIBRA在成纤维细胞（Rat-1）和上皮性乳腺癌细胞（ZR75）中的稳定过表达克隆以及KIBRA在ZR75中的慢病毒短发夹RNA介导的敲低（KD）克隆结果显示，KIBRA过表达时转化特性增加，反之亦然。结果还表明，稳定过表达KIBRA的成纤维细胞在裸鼠中显示出增加的致瘤潜力。通过采用基于定量PCR芯片的方法，我们鉴定出肿瘤抑制因子RASSF1A是KIBRA的转录靶点。