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MicroRNA expression in the macroscopically-normal epithelium of people at differential risk of colorectal cancer

Published online by Cambridge University Press:  30 August 2013

F. Malcomson
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
M. Portilla
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
N. Willis
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
I. McCallum
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
L. Xie
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
S. Kelly
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
M. Bradburn
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
N. J. Belshaw
Affiliation:
Institute of Food Research, Norwich Research Park, Norfolk NR4 7UA, UK
I. T. Johnson
Affiliation:
Institute of Food Research, Norwich Research Park, Norfolk NR4 7UA, UK
J. C. Mathers
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
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Abstract

Type
Abstract
Copyright
Copyright © The Authors 2013 

Colorectal cancer (CRC) is the third most common cancer in the UK. The majority of CRC cases are sporadic( Reference Fearnhead, Wilding and Bodmer 1 ), and the presence of adenomatous polyps or ulcerative colitis (UC) increases CRC risk. In preparation for a study of the effects of a dietary intervention, the present study investigated the expression of 5 microRNAs (miRNAs) reported to be altered in CRC, involved in the WNT pathway and/or implicated in the inflammatory process in people at higher-risk of CRC.

Colorectal mucosal biopsies were collected from normal participants (n=10), participants with quiescent UC (n=9) and participants with prior history of adenomatous polyps (n=9). RNA was extracted from formalin-fixed paraffin-embedded (FFPE) biopsies and reverse transcribed to synthesize cDNA used to quantify the expression of a panel of miRNAs: miR-101, miR-335, miR-122a, miR-135a and miR-145, in duplicate by quantitative PCR. Statistical analysis was performed using the ANOVA General Linear Model.

With relatively small participant numbers, no statistically significant differences were observed for the expression of the selected miRNAs between the 3 groups. However, miR-335 expression, frequently upregulated in CRC, appeared to be increased in polyp patients (Fig. 1A). Participants with UC, an inflammatory disease, appeared to have slightly reduced miR-335 expression, consistent with previous evidence that miR-335 is down-regulated by inflammatory cytokines( Reference Tome, Lopez-Romero and Albo 2 ). In addition, miR-101 and miR-145, both down-regulated in CRC( Reference Strillacci, Griffoni and Sansone 3 , Reference Zhang, Guo and Zhang4 ), appeared to be reduced in higher-risk participants (Fig. 1B and C).

Fig. 1. Mean expression of miR-335 (A), miR-101 (B) and miR-145 (C), expressed as 2−ΔCt×1000 relative to the SNORD68 control.

This study has quantified miRNA expression in FFPE tissue biopsies of normal colorectal mucosa and found evidence of potential differences in those at higher CRC risk. To investigate underlying mechanisms, the methodology developed in this study will be used to measure miRNA expression in healthy participants supplemented with non-digestible carbohydrates, thought to be protective against CRC.

This study was funded by the BBSRC (BB/H005013/1). Ethical approval for this project, as part of a larger application, was granted on 10th December 2009 (REC No. 09/H0907/77).

References

1. Fearnhead, NS, Wilding, JL & Bodmer, WF (2002) Br Med Bull 64, 2743.CrossRefGoogle Scholar
2. Tome, M, Lopez-Romero, P, Albo, C et al. (2011) Cell Death Differ 18, 985–95.Google Scholar
3. Strillacci, A, Griffoni, C, Sansone, P et al. (2009) Exp Cell Res 315, 1439–47.Google Scholar
4. Zhang, J, Guo, H, Zhang, H et al. (2011) Cancer 117, 8695.Google Scholar
Figure 0

Fig. 1. Mean expression of miR-335 (A), miR-101 (B) and miR-145 (C), expressed as 2−ΔCt×1000 relative to the SNORD68 control.