CCAT2 的上调通过抑制乳腺癌中的 P15 促进细胞增殖。

Upregulation of CCAT2 promotes cell proliferation by repressing the P15 in breast cancer.

机构信息

Department of Pancreatic and Breast Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, PR China.

出版信息

Biomed Pharmacother. 2017 Jul;91:1160-1166. doi: 10.1016/j.biopha.2017.05.030. Epub 2017 May 17.

DOI:10.1016/j.biopha.2017.05.030

PMID:28531944

Abstract

BACKGROUND

Long non-coding RNAs (lncRNAs) are demonstrated to function as modulators of both transcriptional and post-transcriptional regulation in various types of tumors progression. The objective of the study is to investigate the clinical significance and underlying mechanism of Colon cancer associated transcript 2 (CCAT2) involved in breast cancer.

METHODS

QT-PCR was performed to examine the relative expression levels of CCAT2 in breast cancer tissues and adjacent normal tissues. Kaplan-Meier survival curves and log rank test were applied to assess the correlation between CCAT2 expression and the overall survival (OS) time in patients. MTT cell proliferation assay, transwell invasion assay and cell cycle analysis were conducted to detect the cell proliferation and invasion. Western blot analysis, RNA immunoprecipitation (RIP) and Chromatin immunoprecipitation (ChIP) assays were performed to detect the association between CCAT2 and P15. The tumor xenograft in nude mice was performed to evaluate the effect of CCAT2 expression on tumor growth in vivo.

RESULTS

Our results confirmed that CCAT2 expression levels in tumor tissues were markedly increased than that in adjacent normal tissues. Higher CCAT2 expression was found to show a significantly correlation with advanced TNM stage and lymph node metastasis in patients. Kaplan-Meier survival curves and log-rank test showed that higher CCAT2 expression was closely correlated with shorter over survival (OS) time in patients. In vitro, knockdown of CCAT2 showed that cell proliferation and invasion capabilities were suppressed and increased G0-G1 phase cell proportion but reduced S phase cell proportion in MCF-7 and MDA-MB-231 cells. Moreover, when CCAT2 silencing, the cell cycle relative protein CyclinD1, CyclinE1 and CDK4 expression were downregulated, but p15 was up-regulated in MCF-7 and MDA-MB-231 cells. Besides, we confirmed that CCAT2 suppressed the p15 expression level via interacting with EZH2 in breast cancer cells. In vivo, the tumor growth was inhibited after knockdown of CCAT2.

CONCLUSION

Our results indicated that CCAT2 may be a potential prognostic marker and therapeutic target for breast cancer.

摘要

背景

长链非编码 RNA（lncRNA）被证明在多种类型肿瘤的进展中作为转录和转录后调控的调节剂发挥作用。本研究旨在探讨结肠癌相关转录物 2（CCAT2）在乳腺癌中的临床意义及其潜在机制。

方法

采用 qt-PCR 检测乳腺癌组织和相邻正常组织中 CCAT2 的相对表达水平。采用 Kaplan-Meier 生存曲线和对数秩检验评估 CCAT2 表达与患者总生存期（OS）时间的相关性。MTT 细胞增殖实验、transwell 侵袭实验和细胞周期分析检测细胞增殖和侵袭能力。采用 Western blot 分析、RNA 免疫沉淀（RIP）和染色质免疫沉淀（ChIP）实验检测 CCAT2 与 P15 的相关性。在裸鼠体内进行肿瘤移植实验，评估 CCAT2 表达对体内肿瘤生长的影响。

结果

本研究证实，肿瘤组织中 CCAT2 的表达水平明显高于相邻正常组织。CCAT2 表达水平与患者的晚期 TNM 分期和淋巴结转移显著相关。Kaplan-Meier 生存曲线和对数秩检验显示，CCAT2 高表达与患者的总生存期（OS）时间明显缩短相关。体外实验结果表明，CCAT2 敲低后 MCF-7 和 MDA-MB-231 细胞的增殖和侵袭能力受到抑制，G0-G1 期细胞比例增加，S 期细胞比例减少。此外，当 CCAT2 沉默时，MCF-7 和 MDA-MB-231 细胞中的细胞周期相关蛋白 CyclinD1、CyclinE1 和 CDK4 的表达下调，而 p15 的表达上调。此外，我们证实 CCAT2 通过与乳腺癌细胞中的 EZH2 相互作用抑制 p15 的表达水平。体内实验结果表明，CCAT2 敲低后肿瘤生长受到抑制。