Gu Juan, Wang Yueping, Wang Xuedong, Zhou Daoping, Wang Xinguo, Zhou Ming, He Zhimin
Department of Medical Laboratory Science, The Fifth People's Hospital of Wuxi, The Medical School of Jiangnan University Wuxi, Wuxi, China.
Department of Pathology, The Fifth People's Hospital of Wuxi, Nanjing Medical University, Wuxi, China.
Cell Physiol Biochem. 2018;48(1):194-207. doi: 10.1159/000491718. Epub 2018 Jul 13.
BACKGROUND/AIMS: An increasing body of evidence shows that long noncoding RNAs (lncRNAs) are involved in many different cancers. In this study, we aimed to investigate the competing endogenous RNA (ceRNA)-dependent mechanism by which the lncRNA GAS5 contributes to the development of breast cancer.
A total of 68 breast cancer patients were enrolled, and breast cancer and adjacent normal tissues were collected. The human breast cancer cell lines MDA-MB-231, MDA-MB-453, BT549, SK-BR-3 and MCF-7 and human breast cell line MCF10A were utilized in this study. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting were performed to detect expression of relative factors. RNA immunoprecipitation (RIP) was used to evaluate the relationship between GAS5 and miR-23a, and a dual luciferase reporter gene assay was employed to assess the relationship between ATG3 and miR-23a. A subcutaneous xenograft nude mouse model was generated to examine the role of GAS5 and its regulatory pathway in autophagy.
GAS5 levels were frequently decreased in breast cancer tissues and cell lines, and its relatively low expression was closely related to a larger tumour size, advanced tumour-node-metastasis (TNM) stage and estrogen receptor-negative (ER-) breast cancer tissues. More importantly, we found that GAS5 promoted autophagy, with enhanced autophagosome formation after GAS5 overexpression. GAS5 was found to act as a microRNA sponge in a pathway that included miR-23a and its target gene ATG3. The GAS5-miR-23a-ATG3 axis significantly regulated autophagy in vivo and in vitro.
In summary, we report that the GAS5-miR-23a-ATG3 axis can be regarded as a key regulator of autophagy pathways in breast cancer; it may constitute a promising biomarker and therapeutic target in the future.
背景/目的：越来越多的证据表明，长链非编码RNA（lncRNA）参与多种不同的癌症。在本研究中，我们旨在探究lncRNA GAS5通过竞争性内源性RNA（ceRNA）依赖机制促进乳腺癌发生发展的机制。
共纳入68例乳腺癌患者，收集乳腺癌组织及癌旁正常组织。本研究使用了人乳腺癌细胞系MDA-MB-231、MDA-MB-453、BT549、SK-BR-3和MCF-7以及人乳腺细胞系MCF10A。采用定量逆转录-聚合酶链反应（qRT-PCR）和蛋白质免疫印迹法检测相关因子的表达。采用RNA免疫沉淀（RIP）技术评估GAS5与miR-23a之间的关系，采用双荧光素酶报告基因检测法评估ATG3与miR-23a之间的关系。建立皮下异种移植裸鼠模型，以研究GAS5及其调控通路在自噬中的作用。
GAS5水平在乳腺癌组织和细胞系中经常降低，其相对低表达与更大的肿瘤大小、更高的肿瘤-淋巴结-转移（TNM）分期以及雌激素受体阴性（ER-）乳腺癌组织密切相关。更重要的是，我们发现GAS5促进自噬，GAS5过表达后自噬体形成增加。发现GAS5在包括miR-23a及其靶基因ATG3的通路中充当微小RNA海绵。GAS5-miR-23a-ATG3轴在体内和体外均显著调节自噬。
总之，我们报道GAS5-miR-23a-ATG3轴可被视为乳腺癌自噬通路的关键调节因子；它可能在未来构成一个有前景的生物标志物和治疗靶点。
