Long noncoding RNA ANRIL indicates a poor prognosis of gastric cancer and promotes tumor growth by epigenetically silencing of miR-99a/miR-449a

Abstract

// Er-bao Zhang 1,* , Rong Kong 1,* , Dan-dan Yin 2,* , Liang-hui You 1 , Ming Sun 1 , Liang Han 3 , Tong-peng Xu 4 , Rui Xia 1 , Jin-song Yang 5 , Wei De 1* , Jin fei Chen 5 1 Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu, PR China; 2 Central laboratory, the Second Affiliated Hospital of Southeast University, Nanjing, Jiangsu, PR China; 3 Department of Oncology, Xuzhou Central Hospital, Affiliated Xuzhou Hospital, College of Medicine, Southeast University, Xuzhou, Jiangsu, PR China; 4 Department of Oncology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR China; 5 Department of Oncology, Nanjing First Hospital, Nanjing Medical University, Nanjing, jiangsu, PR China * contributed equally to this work and should be regarded as joint first authors. Correspondence: Wei De, email: // Jin fei Chen, email: // Keywords : ANRIL; PRC2; miR-99a/miR-449a; proliferation; gastric cancer Received : January 30, 2014 Accepted : April 16, 2014 Published : April 16, 2014 Abstract Long noncoding RNAs are involved in diseases including cancer. Here, we reported that ANRIL (CDKN2B-AS1), a 3.8-kb long noncoding RNA, recruiting and binding to PRC2, was generally upregulated in human gastric cancer (GC) tissues. In a cohort of 120 GC patients, the higher expression of ANRIL was significantly correlated with a higher TNM stage (P=0.041) and tumor size (P=0.001). Multivariate analyses revealed that ANRIL expression served as an independent predictor for overall survival (P=0.036). Further experiments revealed that ANRIL knockdown significantly repressed the proliferation both in vitro and in vivo . We also showed that E2F1 could induce ANRIL and ANRIL-mediated growth promotion is in part due to epigenetic repression of miR-99a/miR-449a in Trans (controlling the targets—mTOR and CDK6/E2F1 pathway) by binding to PRC2, thus forming a positive feedback loop, continuing to promote GC cell proliferation. To our knowledge, this is the first report showed that the role of ANRIL in the progression of GC and ANRIL could crosstalk with microRNAs in epigenetic level. Our results suggest that ANRIL, as a growth regulator, may serve as a candidate prognostic biomarker and target for new therapies in human gastric cancer.