Shen Zhan-Long, Wang Bo, Jiang Ke-Wei, Ye Chun-Xiang, Cheng Cheng, Yan Yi-Chao, Zhang Ji-Zhun, Yang Yang, Gao Zhi-Dong, Ye Ying-Jiang, Wang Shan
Department of Gastroenterological Surgery, Peking University People's Hospital, Beijing, 100044, PR China.
Laboratory of Surgical Oncology, Peking University People's Hospital, Beijing, 100044, PR China.
Oncotarget. 2016 Jun 7;7(23):35092-105. doi: 10.18632/oncotarget.9042.
The progression of distant metastasis cascade is a multistep and complicated process, frequently leading to a poor prognosis in cancer patients. Recently, growing evidence has indicated that deregulation of microRNAs (miRNAs) contributes to tumorigenesis and tumor progression in colorectal cancer (CRC). In the present study, by comparing the miRNA expression profiles of CRC tissues and corresponding hepatic metastasis tissues, we established the downregulation of miR-199b in CRC metastasis tissues. The decrease in miR-199b expression was significantly correlated to late TNM stage and distant metastasis. Moreover, Kaplan-Meier curves showed that CRC patients with high expression level of miR-199b had a longer median survival. Functional assays results indicated that the restoration of miR-199b considerably reduced cell invasion and migration in vitro and in vivo, and increased the sensitivity to 5-FU and oxaliplatin. Further dual-luciferase reporter gene assays revealed that SIRT1 was the direct target of miR-199b in CRC. The expression of miR-199b was inversely correlated with SIRT1 in CRC specimens. SIRT1 knockdown produced effects on biological behavior that were similar to those of miR-199b overexpression. Furthermore, through Human Tumor Metastasis PCR Array we discovered KISS1 was one of the downstream targets of SIRT1. Silencing of SIRT1 upregulated KISS1 expression by enhancing the acetylation of the transcription factor CREB. The latter was further activated via binding to the promoter of KISS1 to induce transcription. Thus, we concluded that miR-199b regulates SIRT1/CREB/KISS1 signaling pathway and might serve as a prognosis marker or a novel therapeutic target for patients with CRC.
远处转移级联的进展是一个多步骤且复杂的过程，常常导致癌症患者预后不良。最近，越来越多的证据表明，微小RNA（miRNA）失调促成了结直肠癌（CRC）的肿瘤发生和肿瘤进展。在本研究中，通过比较CRC组织和相应肝转移组织的miRNA表达谱，我们发现CRC转移组织中miR-199b表达下调。miR-199b表达的降低与晚期TNM分期和远处转移显著相关。此外，Kaplan-Meier曲线显示，miR-199b表达水平高的CRC患者中位生存期更长。功能试验结果表明，恢复miR-199b可在体外和体内显著降低细胞侵袭和迁移，并增加对5-氟尿嘧啶和奥沙利铂的敏感性。进一步的双荧光素酶报告基因试验表明，SIRT1是CRC中miR-199b的直接靶点。在CRC标本中，miR-199b的表达与SIRT1呈负相关。敲低SIRT1对生物学行为产生的影响与miR-199b过表达相似。此外，通过人类肿瘤转移PCR阵列，我们发现KISS1是SIRT1的下游靶点之一。沉默SIRT1通过增强转录因子CREB的乙酰化上调KISS1表达。后者通过与KISS1启动子结合进一步被激活以诱导转录。因此，我们得出结论，miR-199b调节SIRT1/CREB/KISS1信号通路，可能作为CRC患者的预后标志物或新的治疗靶点。
