Expression of Epstein-Barr virus-encoded BamH1-A rightward transcript 7 microRNA in nasopharyngeal carcinoma cells modulates the responsive to irradiation treatment

Background Nasopharyngeal carcinoma (NPC) is highly sensitive to irradiation treatment. Expression of Epstein-Barr virus gene products will affect the radiosensitivity of the cancer cells. Here, the association between EBV BamH1-A rightward transcript 7 microRNA (ebv-miR-BART7) and the effects on irradiation sensitivity was explored. Methods Tissue ebv-miR-BART7 expression level was quantified using real-time quantitative PCR. The radiosensitivity of nasopharyngeal carcinoma cells with ebv-miR-BART7 expression was evaluated by colony formation assay, cell proliferation assay, apoptosis assay, H2AX phosphorylation staining and acridine orange staining. In addition, xenograft model was developed using zebrafish embryo to validate the in vivo radiation sensitivity of the ebv-miR-BART7-expressing NPC. Results Primary NPC tissues and recurrent NPC tissues had a significant higher ebv-miR-BART7 level in comparison with the corresponding normal counterparts. ebv-miR-BART7-expressing NPC cells had higher sensitivity to irradiation treatment. Conclusion Our results suggested that NPC patients have an elevated ebv-miR-BART expression in the primary NPC and recurrent NPC tissue. High ebv-miR-BART increases the sensitivity of NPC cells to irradiation treatment. Further investigation on the clinical value of ebv-miR-BART7 to the therapeutic response is warranted to evaluate the potential use of ebv-miR-BART7 as molecular biomarker in monitoring NPC patients.