miR-340 suppresses tumor growth and enhances chemosensitivity of colorectal cancer by targeting RLIP76

L.-L. Zhang, F.-J. Xie, C.-H. Tang, W.-R. Xu, X.-S. Ding, J. Liang

Department of Medical Oncology, Peking University International Hospital, Beijing, China. xrxbd032@sina.com

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• Oncology

OBJECTIVE: Colorectal cancer (CRC) is a common human malignancy and is the second leading cause of cancer deaths worldwide with a dismal prognosis. Previous investigations have shown that miR-340 can modulate the metabolism of CRC cells. The aim of this report is to study the role of miR-340 in the development and progression of CRC.

PATIENTS AND METHODS: The level of miR-340 in CRC cells was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blotting. CRC cell lines were used as model cell lines and the anti-tumor effect of miR-340 in vitro was examined. The luciferase reporter assay was performed. The level of miR-340 was restored in CRC cells by the usage of the miR-340 mimic. Re-expression of RLIP76 in CRC cells was then constructed. Moreover, the target gene of miR-340 was identified through the experiment of in vivo xenograft model.

RESULTS: The aberrant downregulation of miR-340 is correlated with advanced stage of CRC. Furthermore, the ectopic overexpression of miR-340 in CRC cell lines resulted in growth inhibition, apoptosis and enhanced chemosensitivity in vitro and in vivo, which was mediated by directly targeting RLIP76.

CONCLUSIONS: miR-340 acts as a tumor suppressor in CRC and is involved in the chemoresistance of CRC.

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