MicroRNA-19b-3p Induces Radioresistance In Nasopharyngeal Carcinoma By Targeting TNFAIP3 To Activate NF-?B Pathway

Objective:To investigate the influence of miR-19b-3p on radiation biological characteristics of nasopharyngeal carcinoma(NPC).Methods:Quantitative reverse transcription-polymerase chain reaction analysis(qRT-PCR)was used to analyze the expression of miR-19b-3p in NPC cell lines and NP69.QRT-PCRwas used to analyze the expression of NPC tissues and normal tissues.The effect of miR-19b-3p on radiosensitivity was evaluated by cell viability assays,colony formation assays and in vivo experiment.Apoptosis were examined by flow cytometry.Results:miR-19b-3p was upregulated in NPC.Radioresponse assays showed that miR-19b-3p overexpression resulted in decreased sensitivity to irradiation,whereas miR-19b-3p downregulation resulted in increased sensitivity to irradiation in vitro.Moreover,miR-19b-3p decreased the sensitivity of NPC cells to irradiation in vivo.We found that miR-19b-3p decreased the percentage of apoptosis in NPC cells after irradiation relative to controls.Conclusion:The present study indicated that miR-19b-3p expression was related to the radiosensitivity of NPC and may play an important role in the regulation of cellular radiosensitivity.Objective:To study the mechanism of miR-19b-3p on radiosensitivity of nasopharyngeal carcinoma cellsMethods:Bioinformatic analysis was used to predict miR-19b-3p target genes.QRT-PCR and western blot was performed to analyse the expression of TNFAIP3 mRNA and protein after downregulation and upregulation of miR-19b-3p in NPC cells.Luciferase reporter assay was used to assess the target genes of miR-19b-3p.The effect of TNFAIP3 on radiosensitivity was evaluated by cell viability assays,colony formation assays.Apoptosis were examined by flow cytometry.Expression of target proteins and downstream molecules were analyzed by Western blot.Results:We identified TNFAIP3 was a potential target of miR-19b-3p by Bioinformatic analysis.The expression of TNFAIP3 mRNA and protein was downregulated after upregulation of miR-19b-3p in NPC cells.The expression of TNFAIP3 mRNA and protein was upregulated after downregulation of miR-19b-3p in NPC cells.Luciferase reporter assay confirmed that TNFAIP3 was a direct target gene of miR-19b-3p.Radioresponse assays showed that TNFAIP3 downregulation resulted in decreased sensitivity to irradiation in vitro.We found that TNFAIP3 decreased the percentage of apoptosis in NPC cells after irradiation relative to controls.In either TNFAIP3 knockdown or transfection of miR-19b-3p mimic,p-NF-?B and Bcl-2 level was increased,while Bax and c-capase3 level was decreased.Conclusion:miR-19b-3p contributes to the radioresistance of NPC by activating the TNFAIP3/NF-?B axis.