lncRNA LINC00844 regulates prostate cancer cell migration and invasion through AR signaling [ChIP-seq]

The majority of the human genome is transcribed, yielding a rich repository of non-coding transcripts that are involved in a myriad of biological processes including cancer. However, how non-coding transcripts such as Long Non-coding RNAs (lncRNAs) function in prostate cancer is still unclear. In this study, we have identified a novel set of clinically relevant androgen-regulated lncRNAs in prostate cancer. Among this group, we found LINC00844 is a direct androgen regulated target that is actively transcribed in AR-dependent prostate cancer cells. In clinical analysis, the expression of LINC00844 is higher in normal prostate compared to malignant and metastatic prostate cancer samples and patients with low expression demonstrate poor prognosis and significantly increased biochemical recurrence suggesting LINC00844 may function in suppressing tumor progression and metastasis. From in-vitro loss-of-function studies, we showed LINC00844 prevents prostate cancer cell migration and invasion. Moreover, in gene expression studies we demonstrate LINC00844 functions in trans, affecting global androgen-regulated gene transcription. Mechanistically, we provide evidence to show LINC00844 is important in facilitating AR binding to the chromatin. Finally, we showed LINC00844 mediates its phenotypic effects in part by activating the expression of NDRG1, a crucial cancer metastasis suppressor. Collectively, our findings indicate LINC00844 is a novel coregulator of AR that plays an important role in the androgen transcriptional network and the development and progression of prostate cancer. AR ChIP-seq in LNCaP cells treated with siControl (NC) or siLINC00844#1 and #4 and stimulated with 100nM of DHT or vehicle control for 2 hours. All the experiments are performed in duplicates.

人类基因组的大部分区域均可发生转录，由此产生了丰富的非编码转录本资源库，这类转录本参与包括癌症在内的诸多生物学过程。然而，长链非编码RNA（Long Non-coding RNAs，lncRNAs）这类非编码转录本在前列腺癌中的具体作用机制仍未阐明。本研究在前列腺癌中鉴定出一组全新的、具有临床相关性的雄激素调控型lncRNAs。在该组转录本中，我们发现LINC00844是直接受雄激素调控的靶基因，在雄激素受体（Androgen Receptor, AR）依赖型前列腺癌细胞中被活跃转录。临床分析结果显示，相较于恶性及转移性前列腺癌样本，LINC00844在正常前列腺组织中的表达水平更高；且该基因低表达的患者预后不良，生化复发率显著升高，这提示LINC00844可能通过抑制肿瘤进展与转移发挥抑癌功能。通过体外功能缺失实验，我们证实LINC00844能够抑制前列腺癌细胞的迁移与侵袭能力。此外，基因表达分析结果表明，LINC00844以反式作用方式，影响全局雄激素调控基因的转录。机制层面，我们的研究证据表明，LINC00844对于促进AR与染色质的结合具有关键作用。最后，我们证实LINC00844可通过激活癌症转移关键抑癌因子NDRG1的表达，部分介导其表型效应。综上，本研究结果表明LINC00844是AR的新型共调控因子，在雄激素转录网络以及前列腺癌的发生与进展过程中发挥重要作用。本数据集包含经si对照（NC）或siLINC00844#1、#4处理，并分别用100nM二氢睾酮（Dihydrotestosterone, DHT）或溶剂对照刺激2小时的LNCaP细胞中的AR染色质免疫共沉淀测序（ChIP-seq）数据。所有实验均设置两次生物学重复。