Research Papers:

Down-regulation of long non-coding RNA RP11-708H21.4 is associated with poor prognosis for colorectal cancer and promotes tumorigenesis through regulating AKT/mTOR pathway

Longci Sun, Chunhui Jiang, Chunjie Xu, Hanbing Xue, Hong Zhou, Lei Gu, Ye Liu and Qing Xu _

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Oncotarget. 2017; 8:27929-27942. https://doi.org/10.18632/oncotarget.15846

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Longci Sun1, Chunhui Jiang1, Chunjie Xu1, Hanbing Xue2, Hong Zhou1, Lei Gu1, Ye Liu1, Qing Xu1

1Department of Gastrointestinal Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China

2Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, Shanghai 200001, China

Correspondence to:

Qing Xu, email: celebrationxu@yeah.net

Keywords: colorectal cancer, long noncoding RNA, RP11-708H21.4, RNA sequencing, tumorigenesis

Received: November 02, 2016     Accepted: February 20, 2017     Published: March 02, 2017


Long non-coding RNAs (lncRNAs) serve critical roles in cancer development and progression. Herein, through next generation RNA sequencing and experimental validations, we determined the expression status of RP11-708H21.4 in colorectal cancer (CRC) and explored its clinical significance and biological functions in CRC. Differentially expressed lncRNAs from CRC samples and corresponding normal mucosa tissues was screened through RNA sequencing, and RP11-708H21.4 was selected for further experimental validation. The expression levels of RP11-708H21.4 in CRC tissues and cell lines were determined using qRT-PCR. Also, the relationship between the clinicopathological features and RP11-708H21.4 expression was analyzed. Cell viability was examined by CCK-8 and colony assays; cell migration and invasion were detected by transwell assays; cell cycle and cell apoptosis were analyzed by flow cytometry. The chemosensitivity of CRC cells to 5-Fluorouracil (5-FU) was also determined using CCK-8 assay. CRC xenograft tumor models were established to determine the biological functions of RP11-708H21.4 in vivo. Levels of cell cycle-related proteins and AKT/mTOR pathway-related proteins were detected by western blot assay. RP11-708H21.4 expression was aberrantly decreased in CRC, and its expression was closely associated with aggressive clinicopathologic features and unfavorable prognosis of CRC patients. Overexpressed RP11-708H21.4 suppresses CRC cell proliferation through inducing G1 arrest. Moreover, up-regulation of RP11-708H21.4 inhibits cell migration and invasion, causes cell apoptosis, and enhances 5-FU sensitivity of CRC cells. Finally, increased RP11-708H21.4 expression blocked AKT/mTOR pathway, and repressed in vivo CRC xenograft tumor growth. The results indicated that RP11-708H21.4 might have potential roles as a biomarker and a therapeutic target for CRC.

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