Human Cancer Biology microRNA 223 Is Upregulated in theMultistep Progression of Barrett's Esophagus and Modulates Sensitivity to Chemotherapy by Targeting PARP1

Purpose: Recent microarray and RNA-sequencing studies have uncovered aberrantly expressed microRNAs (miRNA) in Barrett’s esophagus–associated esophageal adenocarcinoma. The functional significance of these miRNAs in esophageal adenocarcinoma initiation and progression is largely unknown. Experimental Design: Expression levels ofmiR-199a/b-3p, -199a-5p, -199b-5p, -200b, -200c, -223, and -375 were determined in microdissected tissues from cardiac mucosa, Barrett’s esophagus, dysplastic Barrett’s esophagus, and esophageal adenocarcinomausing quantitative real-time PCR.miR-223 expression was validated in precursors and esophageal adenocarcinomas from 95 patients with esophageal adenocarcinomaby in situhybridization (ISH).miR-223was transfected into two esophageal adenocarcinoma cell lines, and in vitro assays were conducted. Target genes were identified using Illuminamicroarray, and results were validated in cell lines and human specimens. Results: miR-199 family members and miR-223 were significantly overexpressed in esophageal adenocarcinoma, however, only miR-223 showed a stepwise increase during esophageal adenocarcinoma carcinogenesis. A similar trendwas observed by ISH, which additionally showed thatmiR-223 is exclusively expressed by the epithelial compartment. miR-223–overexpressing cells had statistically significantly more migratory and invasive potential than scramble sequence–transfected cells. PARP1was identified as a direct target gene of miR-223 in esophageal adenocarcinoma cells. Increased sensitivity to chemotherapy was observed in cells with enforced miR-223 expression and reduced PARP1. Conclusions:miR-223 is significantly upregulated during the Barrett’s esophagus–dysplasia–esophageal adenocarcinoma sequence. Although highmiR-223 levelsmight contribute to an aggressive phenotype, our results also suggest that patients with esophageal adenocarcinoma with high miR-223 levels might benefit from treatment with DNA-damaging agents. Clin Cancer Res; 19(15); 4067–78. 2013 AACR.