MiR-205 functions as a tumor suppressor in adenocarcinoma and an oncogene in squamous cell carcinoma of esophagus

Esophageal cancer is a malignant disease with poor prognosis, increasing incidence, and ineffective treatment options. MicroRNAs are post-transcriptional regulators of gene expression involved in many biological processes including carcinogenesis. We determined miR-205 expression levels in tumor/non-tumor tissues of 45 esophageal cancer patients using qPCR and found that decreased level of miR-205 in tumor tissue correlates with poor overall survival in esophageal adenocarcinoma patients. Further, we observed significantly higher levels of miR-205 in tumor tissue of esophageal squamous cell carcinoma. Ectopic overexpression of miR-205 in adenocarcinoma cell line SK-GT-4 led to decreased cell proliferation, cell cycle arrest in G1, and decreased migration ability. Conversely, in squamous cell line KYSE-150, same effects like inhibition of proliferation, migration, and colony-forming potential and cell cycle arrest in G2 were observed after silencing of miR-205. We performed global gene expression profiling and revealed that suppressive functioning of miR-205 in adenocarcinoma could be realized through regulation of epithelial-mesenchymal transition (EMT), whereas oncogenic in squamous cell carcinoma by regulation of metalloproteinase 10. Our results suggest that miR-205 could serve as biomarker in esophageal cancer and acts as a tumor suppressor in esophageal adenocarcinoma and oncogene in esophageal squamous cell carcinoma.