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Open Access Highly Accessed Research article

Suppression of microRNA-31 increases sensitivity to 5-FU at an early stage, and affects cell migration and invasion in HCT-116 colon cancer cells

Chao-Jie Wang1, Johannes Stratmann1, Zong-Guang Zhou2 and Xiao-Feng Sun1*

Author Affiliations

1 Division of Oncology, Department of Clinical and Experiment Medicine, University of Linköping, Linköping, Sweden

2 Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu, PR China

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BMC Cancer 2010, 10:616  doi:10.1186/1471-2407-10-616

Published: 9 November 2010

Abstract

Background

MicroRNAs (miRNAs) are endogenously expressed noncoding RNAs with important biological and pathological functions. Although several studies have shown that microRNA-31 (miR-31) is obviously up-regulated in colorectal cancer (CRC), there is no study on the functional roles of miR-31 in CRC.

Methods

Anti-miR™ miRNA 31 inhibitor (anti-miR-31) is a sequence-specific and chemically modified oligonucleotide to specifically target and knockdown miR-31 molecule. The effect of anti-miR-31 transfection was investigated by real-time PCR. HCT-116p53+/+ and HCT-116p53-/-colon cancer cells were treated by anti-miR-31 with or without 5-fluorouracil (5-FU), cell proliferation was determined by MTT assay; apoptosis was detected by DAPI staining; cell cycle was evaluated by flow cytometry; colony formation, migration and invasion assays were performed to investigate the effect of suppression of miR-31 on the cell lines.

Results

Real-time PCR results showed that anti-miR-31 was efficiently introduced into the cells and reduced miR-31 levels to 44.1% in HCT-116p53+/+ and 67.8% in HCT-116p53-/-cell line (p = 0.042 and 0.046). MTT results showed that anti-miR-31 alone had no effect on the proliferation of HCT-116p53+/+ or HCT-116p53-/-. However, when combined with 5-FU, anti-miR-31 inhibited the proliferation of the two cell lines as early as 24 h after exposure to 5-FU (p = 0.038 and 0.044). Suppression of miR-31 caused a reduction of the migratory cells by nearly 50% compared with the negative control in both HCT-116p53+/+ and HCT-116p53-/-(p = 0.040 and 0.001). The invasive ability of the cells were increased by 8-fold in HCT-116p53+/+ and 2-fold in HCT-116p53-/- (p = 0.045 and 0.009). Suppression of miR-31 had no effect on cell cycle and colony formation (p > 0.05).

Conclusions

Suppression of miR-31 increases sensitivity to 5-FU at an early stage, and affects cell migration and invasion in HCT-116 colon cancer cells.