Suppression of miR-16 promotes tumor growth and metastasis through reversely regulating YAP1 in human cholangiocarcinoma

// Sheng Han 1, * , Dong Wang 1, * , Guohua Tang 1, * , Xinxiang Yang 1 , Chenyu Jiao 1 , Renjie Yang 1 , Yaodong Zhang 1 , Liqun Huo 1 , Zicheng Shao 1 , Zefa Lu 1 , Jiawei Zhang 1 and Xiangcheng Li 1 1 Liver Transplantation Center of The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, P.R. China * These authors contributed equally to this work Correspondence to: Xiangcheng Li, email: drxcli@njmu.edu.cn Keywords: CCA, miRNA, proliferation, metastasis, prognosis Received: January 16, 2017     Accepted: April 19, 2017     Published: May 12, 2017 ABSTRACT Background & Aims: Aberrant expression of microRNAs is associated with many cancers progression. Many studies have shown that miR-16 is down-regulated in many cancers. However, its role in cholangiocarcinoma (CCA) is unknown. Methods: Quantitative real-time PCR (qRT-PCR) was developed to measure miR-16 expression in CCA tissues and cell lines. CCK-8, colony formation and transwell assays were used to reveal the role of miR-16 in CCA cell proliferation and malignant transformation in vitro . The loss-and-gain function was further validated by subcutaneous xenotransplantation and tail vein injection xenotransplantation model in vivo . Dual-luciferase reporter assay was performed to validate the relationship of miR-16 with YAP1. Results: MiR-16 was notably downregulated in CCA tissues, which was associated with tumor size, metastasis, and TNM stage. Both in vitro and in vivo studies demonstrated that miR-16 could suppress proliferation, invasion and metastasis throughout the progression of CCA. We further identified YAP1 as a direct target gene of miR-16 and found that miR-16 could regulate CCA cell growth and invasion in a YAP1-dependent manner. In addition, YAP1 was markedly upregulated in CCA tissues, which was reversely correlated with miR-16 level in tissue samples. Besides, Down-regulation of miR-16 was remarkably associated with tumor progression and poor survival in CCA patients through a Kaplan–Meier survival analysis. Conclusions: miR-16, as a novel tumor suppressor in CCA through directly targeting YAP1, might be a promising therapeutic target or prognosis biomarker for CCA.