miRNAs were involved in the radioresistance of esophageal squamous cell carcinoma

Cancer cells associated with radioresistance are likely to give rise to local recurrence and distant metastatic relapse. However, it remains unclear whether specific miRNAs have direct roles in radioresistance and/or prognosis. In this study, we performed a human miRNA expression array analysis to identify miRNAs upregulated or downregulated in the radioresistant cells. To confirm the results, we selected several candidate miRNAs according to the fold change and function of miRNAs, and detected their expression levels in the radioresistant cells and their parental cells using qRT-PCR. Moreover, we further investigate that specific miRNAs predicts pathological response to preoperative radiotherapy in locally advanced ESCC To establish a radioresistant cell model, we treated human ESCC cell lines (KYSE30, KYSE70 and KYSE180) by applying continuous 2 Gy fractionated irradiations to 60 Gy, and finally obtained a radioresistant subpopulation (designated as KYSE30R, KYSE70R and KYSE180R). These radioresistant and parental cells were selected for RNA extraction and hybridization on Affymetrix microarrays.