MiR-31 dysregulation linked to IBD neoplasia
MedWire News: Dysregulation of micro RNA-31 (miR-31) is associated with progression from chronic inflammation to dysplasia, a precancerous indication, in patients with inflammatory bowel disease (IBD), suggest study results.
“Aberrant miR expression has been linked to carcinogenesis; however, no reports document a relationship between IBD-related neoplasia and altered miR expression,” say Alexandru Olaru (Johns Hopkins University School of Medicine, Baltimore, Maryland, USA) and colleagues.
Olaru and team used miR microarrays and the quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) to test for miR dysregulation in 175 colon samples.
These comprised 55 normal specimens from 14 patients with no history of cancer or IBD, 35 chronically inflamed and 22 noninflamed samples from 35 patients with IBD, 11 samples from patients with IBD dysplasia, 37 samples from patients with IBD-related cancer, and 15 samples from patients with sporadic colorectal cancer.
Microarray analysis identified 32 miRs that were differentially expressed between inflamed and dysplastic colon tissue, 22 of which were upregulated and 10 downregulated in IBD dysplastic versus inflamed colon tissue.
RT-PCR was then used for validated purposes and was carried out on six of the 32 miRs, one of which was miR-31, with differential expression being confirmed for all six types.
When levels of miR-31 expression were assessed at each stage of the IBD neoplastic transformation, levels were found to increase significantly in the progression from chronic inflammation to dysplasia in IBD colon tissue.
In addition, miR-31 levels were 8.2 fold higher in IBD patients compared with controls and 6.23 fold higher in patients with active as opposed to inactive disease.
Of note, no differences in miR-31 expression were seen between IBD dysplasia and IBD carcinoma, suggesting that “miR-31 upregulation is an early event in the neoplastic transformation,” say the authors.
Overall, expression of miR-31 was 61.38 and 11.00 fold higher in specimens from patients with IBD neoplasia than those from controls and patients with IBD, respectively.
“Taken together, these results suggest that miR-31 exhibits a stepwise progression from normal to chronic inflammation to neoplasia,” conclude Olaru et al in the journal Inflammatory Bowel Diseases.
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By Helen Albert