[1831] miRNA Profiling by Next Generation Sequencing and miRNA ISH in Ulcerative Colitis Neoplastic Progression

Noah C Welker, Jingmei Lin, Mary P Bronner. ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT; University of Indiana, Indianapolis, IN; University of Utah, Salt Lake City, UT

Background: Ulcerative colitis (UC) represents a classic chronic inflammatory disease model linked to neoplastic progression. While the lifetime risk of colon cancer is only ∼10% in UC, no effective means currently exist to distinguish this subset. Prior UC studies reveal widespread colonic mucosal molecular alterations that extend far beyond histologic dysplasia to even involve nondysplastic rectal mucosa. Improved bioclassifiers that build on this knowledge in UC are highly sought after to better identify the subset of patients most likely to benefit from expensive and difficult surveillance procedures.
Design: Non-dysplastic rectal biopsies were analyzed from 10 UC patients with synchronous but distant colon cancer (UC-progressors), 10 without dysplasia for >10 years (UC-nonprogressors), and 18 normal controls. Next generation small RNA sequencing was performed on the Illumina platform. Data were analyzed using the USeq software package to determine regions of differential expression between these patient groups. RT-PCR, in situ hybridization, and immunohistochemistry were performed for validation purposes and to identify which cells differentially express micro-RNAs within the tested biopsies.
Results: While 11 miRNAs were misregulated in both UC patient groups compared to normals, a total of 33 miRNAs were differentially expressed between progressors and nonprogressors using our statistical criteria (fold change >2, false discovery rate < 0.10). RT-PCR confirmed these RNA-sequencing results. Of particular interest, mir-155 was overexpressed in UC-nonprogressors, but not UC-progressors. Mir-155 has been implicated in the regulation of T-cell subsets, particularly Th17 cells that express IL-17. In situ hybridization using a mir-155 specific probe and IHC staining for IL-17 validate these biomarkers in situ within lamina propria lymphocytes.
Conclusions: We have identified a subset of miRNAs that are specifically misregulated in UC-nonprogressor and progressors that may prove useful as a biomarker panel to enhance early cancer detection and prevention in UC. Mir-155 is implicated in controlling the immune cell environment in UC. Its involvement as a biomarker has been validated by RT-PCR, in situ hybridization and immunohistochemistry for TH17 cells in nondysplastic rectal biopsies.
Category: Special Category - Pan-genomic/Pan-proteomic approaches to Cancer

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 232, Tuesday Morning


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