MicroRNA expression profiling in human Barrett's carcinogenesis

Abstract

Barrett's esophagus (BE) is characterized by the native stratified squamous epithelium (N) lining the esophagus being replaced by a columnar epithelium with intestinal differentiation (Barrett's mucosa; BM). BM is considered as the main risk factor for esophageal adenocarcinoma (Barrett's adenocarcinoma; BAc). MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting messenger RNAs and they are reportedly dysregulated in BM. To test the hypothesis that a specific miRNA expression signature characterizes BM development and progression, we performed miRNA microarray analysis comparing native esophageal mucosa with all the phenotypic lesions seen in the Barrett's carcinogenic process. Specimens were collected from 14 BE patients who had undergone esophagectomy, including: 14 with N, 14 with BM, 7 with low-grade intraepithelial neoplasia, 5 with high-grade intra-epithelial neoplasia and 11 with BAc. Microarray findings were further validated by quantitive real-time polymerase chain reaction and in situ hybridization analyses using a different series of consecutive cases (162 biopsy samples and 5 esophagectomies) of histologically proven, long-segment BE. We identified a miRNA signature of Barrett's carcinogenesis consisting of an increased expression of 6 miRNAs and a reduced expression of 7 miRNAs. To further support these results, we investigated target gene expression using the Oncomine database and/or immunohistochemical analysis. We found that target gene expression correlated significantly with miRNA dysregulation. Specific miRNAs are directly involved in BE progression to cancer. miRNA profiling significantly expands current knowledge on the molecular history of Barrett's carcinogenesis, also identifying molecular markers of cancer progression.

Early Diagnostic Biomarkers for Esophageal Adenocarcinoma—The Current State of Play

“…Among miRNAs found to be downregulated during EAC development, let-7 family of miRNAs is tumor-suppressive and negatively regulates Ras oncogene. Fassan and colleagues confirmed upregulation of HMGA2, which is one of the target of let-7 miRNA, using immunohistochemistry in tissue samples (110,112,114). Further studies in the regards of miRNA and miRNA target genes will improve the biologic understanding of EAC pathogenesis and may also provide novel molecular targets for disease intervention.…”

PDCD4 nuclear loss inversely correlates with miR-21 levels in colon carcinogenesis

“…Briefly, slides were incubated at 60°C for 30 min and deparaffinized as described in [24,32]. Sections were treated with Proteinase K (DakoCytomation) for 30 min at room temperature, rinsed several times with dH 2 O, and immersed in 95% ethanol for 10 s before air-drying.…”

MicroRNA Profiles in Familial and Sporadic Medullary Thyroid Carcinoma: Preliminary Relationships with RET Status and Outcome

“…ISH was performed using the GenPointÔ Catalyzed Signal Amplification System (DakoCytomation, Carpinteria, CA) according to the manufacturer's protocol. Briefly, slides were incubated at 60°C for 30 minutes and deparaffinized, as described elsewhere (20,21). Sections were treated with Proteinase K (DakoCytomation) for 30 minutes at room temperature, rinsed several times with dH 2 O, and immersed in 95% ethanol for 10 seconds before air-drying.…”