Long non-coding RNA Malat1 promotes gallbladder cancer development by acting as a molecular sponge to regulate miR-206

// Shou-Hua Wang 1, * , Wen-Jie Zhang 1, * , Xiao-Cai Wu 1 , Ming-Di Zhang 1 , Ming-Zhe Weng 1 , Di Zhou 1 , Jian-Dong Wang 1 , Zhi-Wei Quan 1 1 Department of General Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200000, China * Co-first authors, these authors contributed equally to this work Correspondence to: Zhi-Wei Quan, email: Quanzhiwei3@163.com Keywords: lncRNA, Malat1, miR-206, competing endogenous RNA, gallbladder cancer Received: February 01, 2016      Accepted: April 26, 2016      Published: May 13, 2016 ABSTRACT Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (Malat1) functions as an oncogene in many types of human cancer. In this study, we show that Malat1 is overexpressed in gallbladder cancer (GBC) tissue and cells. The high Malat1 levels correlated positively with tumor size and lymphatic metastasis, and correlated negatively with overall survival. We also show that Malat1 functions as a competing endogenous RNA (ceRNA) for miR-206. Because miR-206 directly suppresses expression of ANXA2 and KRAS, which are thought to promote GBC progression, Malat1 binding of miR-206 in GBC tissue and cells has an oncogenic effect. Conversely, Malat1 knockdown inhibits proliferation and invasion by GBC cells while increasing apoptosis. In vivo , silencing Malat1 decreases tumor volume. These results suggest Malat1 could potentially serve as a therapeutic target and prognostic marker for GBC.