Effects Of The HDAC Inhibitor Quisinostat On Proliferation And Apoptosis Of Nasopharyngeal Carcinoma Cell Line CNE1

Background Studies have shown that EB(Epstein-Barr)virus infection is closely related to the occurrence and development of nasopharyngeal carcinoma(NPC).Epstein-Barr virus encoded latent membrane protein 1(LMP1)is the major transforming gene product of the virus.LMP1 is expressed in most Epstein-Barr virus-associated lymphoproliferative and malignancies and promotes pathogenesis and disease phenotype.Studies have shown that LMP1 can promote target cell proliferation and subvert cell death program.The expression of LMP1 in nasopharyngeal carcinoma cells has certain specificity.LMP1 is a potential target for clinical treatment of nasopharyngeal carcinoma as an important factor of virus-host interaction.Epigenetic processes are closely linked to cancer progression.Acetylation of histones modulates transcription factors into the DNA and affects gene expression levels.Decreased histone deacetylase(HDAC)activity leads to a decrease in histone acetylation,resulting in tight binding of the DNA / histone complex,thereby blocking gene transcription.HDAC inhibitors promote the growth arrest,differentiation and apoptosis of tumor cells and have almost no effect on normal tissues.A large number of HDAC inhibitors are used in clinical treatment of lymphoma,but few reports of solid tumor nasopharyngeal carcinoma.We will explore the role of Quisinostat(JNJ-26481585,JNJ),a second-generation new HDAC inhibitor,in nasopharyngeal carcinoma in vivo and in vitro to provide new options for the clinical treatment of nasopharyngeal carcinoma.Methods 1?Detect the gene expression level of Epstein-Barr virus membrane protein LMP1 in cancer tissues and adjacent tissues of clinical nasopharyngeal carcinoma patients by RT-PCR.2?Stable expression of Epstein-Barr virus membrane protein LMP1 in CNE1 cell line of nasopharyngeal carcinoma(CNE1-3G cells are control cells expressing empty vector and CNE1-3G-LMP1 is stable cell line overexpressing LMP1).The efficiency of LMP1 expression in CNE1 cells was examined by western blotting and immunofluorescence.The effect of LMP1 overexpression on the proliferation of CNE1 cells was investigated by colony formation experiment and Ki-67 immunofluorescence staining assay.3?The sensitivity of CNE1-3G and CNE1-3G-LMP1 cells to HDAC inhibitor JNJ was investigated by MTT assay.The effect of HDAC inhibitor JNJ on the apoptosis of CNE1-3G and CNE1-3G-LMP1 cells was investigated by western blotting to detect the expression of apoptosis related proteins and Annexin V-FITC / PI double staining assay.4?To study whether HDAC inhibitor JNJ can selectively act on LMP1-positive nasopharyngeal carcinoma cells,we performed nude mice subcutaneous tumorigenesis experiment.The same number of CNE1-3G and CNE1-3G-LMP1 cells were injected subcutaneously into nude mice(10 in each group,half in both sexes).When hypodermal tumor appeared in nude mice,intraperitoneal injection of HDAC inhibitor JNJ.The size of tumor and the weight of nude mice were recorded daily.Results 1? Epstein-Barr virus membrane protein LMP1 promotes the proliferation of nasopharyngeal carcinoma CNE1 cells.The number of colonies and Ki-67 positive cells were significantly increased in CNE1-3G-LMP1 cells compared to CNE1-3G cells.2? HDAC inhibitor JNJ selectively acts on LMP1-positive CNE1-3G-LMP1 cells and significantly inhibits the proliferation ability of CNE1-3G-LMP1 cells in vitro.After treated with HDAC inhibitor JNJ,the number of colonies were significantly decreased in LMP1-overexpressed CNE1-3G-LMP1 cells compared to CNE1-3G cells.Consistently,the percentage of Ki-67 positive cells is also decreased.3? Epstein-Barr virus membrane protein LMP1 promotes the tumorigenesis ability of nasopharyngeal carcinoma cells,HDAC inhibitor JNJ specifically targets LMP1-positive NPC cells.Nude mice subcutaneous tumor formation test results show:(1)The tumorigenicity of CNE1-3G-LMP1 cells was significantly stronger than that of CNE1-3G cells;(2)CNE1-3G-LMP1 cells in JNJ group injected intraperitoneally with HDAC inhibitor were significantly smaller than those in CNE1-3G-LMP1 cells injected with PBS group;(3)The intraperitoneal injection of HDAC inhibitor JNJ group showed no significant difference compared to in CNE1-3G cells.Conclusions 1? Epstein-Barr virus membrane protein LMP1 promotes proliferation and tumorigenicity of nasopharyngeal carcinoma cell line CNE1.2? HDAC inhibitor JNJ specifically inhibits the proliferation and induces apoptosis of LMP1-positive NPC cells.3? HDAC inhibitor JNJ specifically targets LMP1-positive CNE1 cells in vivo and inhibit its tumorigenicity.