The latent gene expression of Epstein-Barr virus in nasopharyngeal carcinoma

AIM: To examine the latent membrane protein 1(LMP1)-DNA sequence in nasopharyngeal carcinoma(NPC) and detect mRNA expression of LMP1,EBNA1,EBNA2,and to explore the relationship between EBV infectious status,expression products and NPC carcinogenesis.METHODS: LMP1 DNA was detected in NPC by PCR.Direct sequence was applied to analyze the difference between NPC-LMP1-DNA and B95-8- LMP1-DNA.mRNA expressions of LMP1,EBNA1,EBNA2 in NPC were detected by nested RT-PCR.RESULTS: LMP1 DNA existed in all 47 NPC tissues.Several single nucleotide variations were found between NPC-LMP1-DNA and B95-8- LMP1-DNA.The notable variation was the lost of XhoⅠrestriction site in NPC.Direct sequence showed 30 bp deletion in NPC.The mRNA expressions of LMP1,EBNA1 and EBNA2 in NPC were 76.6%,80.0% and 74.5% respectively by nested RT-PCR.The expression of EBNA1 in NPC was promoted by Q promoter while the expression of EBNA1 in B95-8 was promoted by C promoter.CONCLUSION: The way of EBV involved in NPC is complex.Latent genes such as LMP1,EBNA1 and EBNA2 as well as early lytic gene BARF1 may all play certain roles in NPC carcinogenesis.     

Construction of shRNA targeting AGR2 gene and effect of AGR2 on biological function of nasopharyngeal carcinoma cells

AIM: To construct the shRNA targeting anterior gradient protein 2 (AGR2) gene for exploring the effect of AGR2 on the biological behavior of nasopharyngeal carcinoma (NPC) cells.METHODS: The expression of AGR2 at mRNA and protein levels in NPC cell lines 6-10B and 5-8F was detected by real-time PCR and Western blot. The pSR-GFP/Neo-AGR2-shRNA expression vector targeting AGR2 was constructed. Based on the interference targeting AGR2, the cell migration and motility were determined by Transwell migration and motility assays.RESULTS: The expression of AGR2 was increased in NPC cell line 5-8F compared with NPC cell line 6-10B (P<0.05). When the AGR2 expression in 5-8F cells was interfered, the cell migration, invasion and tumorigenicity were weakened.CONCLUSION: The expression of AGR2 is up-regulated in NPC cell line 5-8F. pSR-GFP/Neo-CLU-shRNA successfully inhibits the expression of AGR2 in NPC cell line 5-8F. AGR2 inhibits the migration, invasion and tumorigenicity of 5-8F cells in vivo.     

Relationship between radioresistance and microRNA in the same genetic background nasopharyngeal carcinoma cells

AIM:To discuss the relationship between the discrepancy of microRNA (miRNA) and radioresistance in nasopharyngeal carcinoma (NPC) cells CNE-2R and CNE-2 on the basis of validating their different radioresistance.METHODS:Following the exposure of X ray on the clones of CNE-2R and CNE-2 cells, the dose-survival curve and biological characteristics of CNE-2R and CNE-2 cells were determined by SigmaPlot software and the linear quadratic model of survival curve analysis.MicroRNAs were detected by μParafloTM microfluidic chip, hybridization images collected by a laser scanner (GenePix 4000B, Molecular Device) and the signals normalized by a LOWESS filter.The relationship between the discrepancy of NPC radioresistance and the expression of miRNA was predicted according to Targetscan3.1 database (http://www.targetscan.org) after analyzing the data.RESULTS:Compared to CNE-2 cells, 37 miRNAs were gain-of-function and 29 miRNAs were loss-of- function in CNE-2R cells among 719 detected miRNAs.12 miRNAs that detective value was more than 2 000 and 2 folds than the other were hsa-miR-200b, hsa-miR-224, hsa-miR-26b, hsa-miR-125a-5p, hsa-miR-205, hsa-let-7e, hsa-let-7g, hsa-miR-19b, hsa-miR-24, hsa-miR-103, hsa-miR-106b and hsa-miR-93.Data showed that the distinct discrepancy of miRNAs was related to radioresistance.CONCLUSION:The discrepancy of miRNAs is present in different radioresistant NPC cell lines and related to radioresistance.     

Expression of molecular markers Jab1 and Akt1 in recurrent nasopharyngeal carcinoma

AIM：To analyze the expression of Jab1 and Akt1 in paired human primary and recurrent nasopharyngeal carcinoma (NPC) tissues, to explore the relationships between their expression and molecular mechanism and further to identify the potential treatment target of rNPC. METHODS：Paired primary and recurrent NPC archival samples (n=45) from Affiliated Foshan Hospital and Affiliated Shantou Hospital of Sun Yat-sen University were collected. The expression of Jab1 and Akt1 was determined by the method of immunohistochemistry (SABC). The expression of Jab1 and Akt1 in CNE-1, CNE-2, CNE-2R and HONE1 cells before and after ionizing radiation (IR) was detected by Western blotting. RESULTS：The expression of Jab1 and Akt1 increased in recurrent NPC tissues compared with the primary tumors (both P<0.05). The expression of Jab1 and Akt1 increased in CNE-1, CNE-2R and HONE1 cells in comparison with CNE-2 cells. Furthermore, Jab1 expression was elevated in CNE-1, CNE-2, CNE-2R and HONE1 cells after receiving IR. CONCLUSION：Over-expression of Jab1 and Akt1 contributes to the resistance of NPC cells with irradiation, and induces recurrence of NPC. Therefore, Jab1 and Akt1 serve as potential tumor targets for the treatment of recurrent NPC.     

Inhibitory role of epigallocatechin-3-gallate in proliferation of human nasopharyngeal carcinoma cells by targeting P53/miR-34a

AIM: To study the effect of epigallocatechin-3-gallate(EGCG) on the proliferation of human nasopharyngeal carcinoma(NPC) cells, and to explore its mechanism by targeting miR-34a.METHODS: Nasopharyngeal carcinoma CNE-2Z cells were treated with various concentrations of EGCG. The ability of cell proliferation was detected by CCK-8 assay, 5-ethynyl-2-deoxyuridine(EdU) incorporation assay and colony-forming assay. The cell cycle distributions were analyzed by flow cytometry. The protein levels of P53 and Notch1 were detected by Western blot. The expression of miR-34a and Notch1 mRNA was measured by real-time PCR.RESULTS: EGCG effectively inhibited the proliferation and colony formation of CNE-2Z cells in a dose-dependent manner, which was related to its induction of cell cycle arrest at G₀/G₁ phase. The expression of P53 and miR-34a in CNE-2Z cells was significantly increased after treated with EGCG, while the expression of Notch1 at mRNA and protein levels was markedly suppressed.CONCLUSION: EGCG induces cell cycle arrest and suppresses cell proliferation by regulating the P53/miR-34a/Notch1 pathway in NPC cells.     

T63 enhances radiotherapeutic sensitivity of nasopharyngeal carcinoma cells through apoptosis and G2/M arrest

AIM: To explore the antitumor effect of a curcumin analogue T63 in human nasopharyngeal carcinoma (NPC) cell lines CNE-2 and CNE-2R. METHODS: Cell viability was monitored by the methods of MTT and colony formation assay. Cell cycle distribution was detected by flow cytometry. Apoptosis was examined using the annexin V-FITC/PI staining assay. RESULTS: A growth inhibitory effect was observed with T63 treatment in a dose-dependent manner. Either T63 or ionizing radiation (IR) significantly induced G2/M arrest and apoptosis in NPC cells. In addition, T63 treatment combined with IR induced significantly higher apoptosis and G2/M arrest in NPC cells. CONCLUSION: T63 exhibits potent inhibitory activity on NPC cells and induces the radiotherapeutic sensitivity. Therefore, T63 has a potential as a preventive or therapeutic agent for treating NPC.     

Identification of proteins related to proliferation and regulated by Epstein Barr virus encoded latent membrane protein 1 in nasopharyngeal epithelail cells

AIM: To investigate the molecular mechanism of Epstein-Barr virus encoded latent membrane protein 1 regulated cellular proliferation in nasopharyngeal epithelial cells. METHODS: The nasopharyngeal epithelial cells NP69 were infected with RV-pLNSX (the empty vector) and RV-LMP1 retroviruses, respectively. Therefore, the NP69-pLNSX and NP69-LMP1 cell lines were established. Sequentially, cellular proliferation of NP69-pLNSX and NP69-LMP1 cells was compared to draw the cellular growth curve. The experiments of plate clone formation and forming of soft agar colony were conducted. Meanwhile, the differential expression of proteins were identified between NP69-pLNSX and NP69-LMP1 cell lines by proteomic methods, and the expression levels of partial identified proteins were verified. RESULTS: (1) LMP1 was able to accelerate cellular proliferation of nasopharyngeal epithelial cell NP69 (n=3, P<0.05). (2) Twenty two proteins (9 up-and 13 down-regulated) of LMP1 mediated regulation were identified from infected NP69 cell lines, and the differential expression of partial identified proteins was confirmed by Western blotting and fluorescent real-time quantitative RT-PCR. CONCLUSION: LMP1 probably mediates the regulation of vimentin protein and keratin 19 protein expression to promote cellular proliferation in NP69 cells.     

Differences of genome-wide methylation level and methylated genes between nasopharyngeal carcinoma cells in same genetic background but different radiation resistance

AIM: To compare the differences of the genome-wide methylation levels and methylated regions between nasopharyngeal carcinoma (NPC) cells in the same genetic background but different radiation resistance (CNE-2 cells and CNE-2R cells). METHODS: Using the method which was developed by Doctor Zhao Cun-you, based on using methyl-sensitive restriction enzyme to measure the genome-wide methylation levels. In addition, MeDIP-Seq was used to analyze the methylated regions in 6 gene functional elements, including the upstream 2k sequence, 5'UTR, coding sequence, intron, 3'UTR and downstream 2k sequence, between CNE-2 cells and CNE-2R cells. RESULTS: The genome-wide methylation level was approximately 30% lower in CNE-2R cells than that in CNE-2 cells. No obvious difference on the amount of genes and the coverage of the peak in the 6 gene functional elements was observed. However, the methylation pattern of plentiful genes had altered in the gene function elements. CONCLUSION: The genome-wide methylation levels and methylated regions between NPC cells in the same genetic background but different radiation resistance were quite different, indicating that the DNA methylation may be associated with NPC radioresistance.     

Construction of SETD2 gene knockout nasopharyngeal carcinoma cell strains using CRISPR/Cas9 technique and analysis of their proliferation property

AIM:To establish SETD2 gene knockout nasopharyngeal carcinoma (NPC) cell strains based on CRIPSR/Cas9 technique and to analyze their proliferation characteristics. METHODS:Sub-quantitative RT-PCR and Western blot were used to detect the expression of SETD2 in immortalized nasopharyngeal epithelial cell line NP-69, well differentiated NPC cell line CNE1, poorly-differentiated NPC cell line CNE2Z and undifferentiated NPC cell line C666-1, and the SETD2 high expression cell line CNE1 was screened. The proliferation ability of CNE1 cells before and after the SETD2 gene knockout was analyzed by CCK-8 and colony formation assay. The cell cycle distribution was detected by flow cytometry, and the expression of cell cycle-related proteins was detected by Western blot. RESULTS:Compared with NP-69 cells, the expression of SETD2 was decreased gradually in CNE1, CNE2Z and C666-1 cells (P<0.01). Based on the CRISPR/Cas9 technique, 2 monoclonal cell strains with SETD2 gene stable knockout, named CNE1-SETD2-KO-#5 and #9, were successfully screened from total 15 monoclones. The results of CCK-8 and plate colony formation assay confirmed that the proliferation ability of CNE1-SETD2-KO-#5 and #9 cells was significantly enhanced compared with CNE1-WT cells (P<0.05). The results of flow cytometry analysis showed that the G₁ phase of CNE1-SETD2-KO-#5 and #9 cells was decreased, while the G₂/M and S phases were increased significantly (P<0.05). The results of Western blot confirmed the increases in the protein levels of proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin B1, cyclin A2, cyclin E1, cyclin-dependent kinases 2 (CDK2) and CDK4, and the decrease in the protein level of p21 after SETD2 gene knockout (P<0.05). CONCLUSION:The NPC cell strains with SETD2 gene knockout were successfully constructed based on CRISPR/Cas9 technique. SETD2 expression correlates with cell differentiation status in the NPC cells. SETD2 gene knockout promotes NPC cell proliferation by up-regulating cyclin D1, cyclin B1, cyclin A2, cyclin E1, CDK2 and CDK4, and down-regulating p21 expression.     

Effect of Ad-14-3-3σ on microRNA expression in different radioresistant nasopharyngeal carcinoma cells

AIM: To discuss the effect of Ad-14-3-3σ to microRNA (miRNA) in different radioresistant nasopharyngeal carcinoma (NPC) cells, CNE-1 and CNE-2, and study the relationship between the discrepancy of miRNA and radiosensitivity of NPC.METHODS: Ad-14-3-3σ was transfected to CNE-1 and CNE-2 cells, and then miRNAs were detected by Paraflo microfluidic microRNA chip. Hybridization images were collected using a laser scanner and the signals were normalized using a LOWESS filter. The effect of Ad-14-3-3σ to miRNAs and the relationship between the discrepancy of miRNA and radiosensitivity of NPC were studied according to Targetscan3.1 database (http://www.targetsan.org) after analyzing data.RESULTS: After treated by Ad-14-3-3σ, comparing to CNE-2 cells, there are 37 miRNAs changed remarkably, including 17 over-expression microRNAs and 20 under-expression microRNAs in CNE-1 cells. 6 miRNAs that one detective value was more than 1 000 and 3 folds than the other were hsa-miR-152,hsa-miR-205,hsa-miR-203,hsa-miR-7,hsa-miR-636 and hsa-miR-100.CONCLUSION: Ad-14-3-3σ can change the expression of miRNAs in different radioresistant nasopharyngeal carcinoma, and some miRNAs have relevance to carcinoma and radiosensitivity.     

Inhibitory effect of polypeptide from Buthus martensii Karsch on neoplasm cells

AIM: To observe the inhibitory effects of polypeptide from Buthus martensii venom (PBMV) on human tumor cell lines and the influence of PBMV on cell cycle migration, expression of tumor-suppressor gene p53 and the membrane potential of CNE-2Z cells. METHODS: MTT colorimetric method, the colony formation and mitosis index, flow cytometry assay and intracellular recording with glass microelectrodes were used. RESULTS: PBMV had obvious cytotoxicity on several tumor cell lines. The cells grow was inhibited by PBMV, colony formation rate and mitotic index of tumor cells were reduced and the number of polykaryocyte was decreased. CNE-2Z cells in S phase were reduced evidently after they were treated with PBMV (P<0.01). After CNE-2Z cells were incubated with PBMV, P53 protein expression in the cells decreased obviously. Differences were very distinct (P<0.01). The negative potential of cell membrane reduced evidently and cell membrane was in depolarization state. CONCLUSION: PBMV probably possesses the effects of the "membrane toxin". By decreasing the membrane potential, the growth and proliferation of tumor cells were interfered by PBMV.     

Effect of PRL-2 gene transfection on proliferation and cell cycle in hepatocellular cell line

AIM: To observe the changes of proliferation and cell cycle after PRL-2 gene effectively expressed in human hepatocellular cell line.METHODS: The PRL-2 vector was transfected into CL1 cell with lipofectamine reagent,the stable expression clones were screened by G418.The expression of PRL-2 mRNA was detected by real-time PCR.The expressive protein was identified by Western blotting.The subcellular localization was demonstrated by immunochemistry.The cell cycle was measured by flow cytometry.The population doubling time (TD) was analyzed by MTT assay.The expressions of cyclin A,cyclin D1,cyclin E,p16,p21Waf1 and p27Kip1 were detected by Western blotting.The p21Waf1 mRNA was determined by real- time PCR.RESULTS: The full length ORF of PRL-2 gene was inserted into the vector pcDNA3.1 (+),transfected into CL1 cells,and expressed successfully.Real-time PCR showed stable expression of PRL-2 mRNA.Western blotting confirmed the overexpression of PRL-2 protein.The subcellular localization of PRL-2 was in the plasmid.The proportion of cells in S-phase was increased.The population doubling time was reduced (P<0.01),a significant decrease was observed both in the mRNA and the protein expression of the p21Waf1 in comparison with untransfected or vector- transfected control cells (P<0.05).The expressions of cyclin D1,cyclin E,cyclinA,p16 and p27Kip1 were not appreciably different between the control and PRL-transfected cell lines.CONCLUSION: Eukaryocytic expression vector of PRL-2 has been successfully constructed,which shows stable and effective expression in CL1 cell line.PRL -2 increases cell proliferation by stimulating progression from G1 into S phase,which is primarily associated with decreased p21Waf1.     

Effects of two EBV-LMP1 variants on proliferation characteristics of CNE1 cell line

AIM: To investigate the possible effect of different Latent membrane protein 1 (LMP1) variants on proliferation characteristics of a human well-differentiated nasopharyngeal carcinoma (NPC) cell line CNE1. METHODS: The plasmids which carried EBV-LMP1 gene cloned from B95-8 lymphocyte (B95-8-LMP1) and NPC tissues (CAO-LMP1) were introduced into CNE1 by liposomal transfection. Expression of LMP1 in CNE1 was identified by RT-PCR and Western blot, respectively. Different Effects of the two EBV-LMP1 variants on proliferation characteristics of CNE1 including growth curve, cell cycle distribution and clony-forming efficiency were investigated by means of crystal violet staining proliferation assay, flow cytometry and plastic plate clony-forming assay, respectively. RESULTS: Two transfected cell lines stably expressing different LMP1 variants were established successfully. Either of the two LMP1 variants increased CNE1 growth rate, proliferation index (PI) and clony-forming rate significantly and CAO-LMP1 had more significant growth-promoting effect on CNE1 than B95-8-LMP1. CONCLUSION: It can be concluded from the study that CAO-LMP1 promotes CNE1 proliferation more effectively than B95-8-LMP1.     

Effect of protein kinase C-α antisense oligonucleotide on cell cycle of CNE-2Z cells

AIM:To observe the effect of protein kinase C-α(PKCα)antisense oligonucleotide on cell growth, cell cycle and the expression of cyclin E in human poor-differentiated nasopharyngeal carcinoma(NPC) cell line CNE-2Z. METHODS:Antisense PKCα was transfected by cationic liposome(LP) in CNE-2Z cells to analyze the cell growth and cell cycle by MTT colorimetric assay and flow cytometry, respectively. Moreover, the expression of cyclin E was determined by immunocellularchemistry and scanning the result of dot-blotting. RESULTS:①With the concentration of antisense PKCα increasing, the relative cell growth index was decreased gradually(P＜0.01). ②After treated with antisense PKCα, the percentage of cells in G₁ phase enhanced(P＜0.05). ③Compared with the control group, the expressing intensity of cyclin E reduced in antisense PKCα group, and the expression of cyclin E decreased to 66.5%±18.4％(P＜0.05) of the control by scanning quantitative analysis. CONCLUSION:These results indicated that antisense PKCα may inhibit cell growth in CNE-2Z via suppressing the expression of cyclin E and hindering cell process in G₁ phase.     

Construction of HLCDG1 gene siRNA expression vector and its regulation on cell cycle and proliferation in A549 cells

AIM:HLCDG1 is a novel gene cloned recently, and its expression inhibits significantly the growth of A549 cells and tumorigenesis of A549 cells transplanted in nude mice. In this study, our aim was to construct HLCDG1 gene short/small interference double-strand RNA (siRNAs) expression vector and to observe its influence on cell cycle and proliferation of A549 cells. METHODS:Using RNA interference (RNAi) techniques, a DNA vector-driven siRNAs expression vector was constructed, and a lung carcinoma cell line stably expressing siRNAs was also selected. Sequentially, using flow cytometry analysis and MTT assay, the changes of cell cycle and cell proliferation in this cell line were observed. RESULTS:Four site-match and one site-mismatch plasmids were constructed, which were named pHL-si-1, pHL-si-2, pHL-si-3, pHL-si-4 and pHL-si-c. These plasmids were co-transfected with a pcDNA3.1(+)/HLCDG1 plasmid into A549 cells, respectively. Among five co-transfected A549 cell lines, a A549 cell line co-transfected by the pcDNA3.1(+)/HLCDG1 and pHL-si-1 plasmids, namely A549-HLCDG1-si-1, showed nearly complete inhibition of HLCDG1 expression. MTT assay and flow cytometry analysis indicated that A549-HLCDG1-si-1 cells, namely the HLCDG1 gene-silencing cells, got a faster growth compared with other HLCDG1 expression cell lines, and that HLCDG1 gene-silencing induced A549-HLCDG1-si-1 cells into S phase and G2+M phase significantly. CONCLUSION:These results suggest that the HLCDG1 gene is proved to have a markedly inhibitory effect on growth in A549 lung carcinoma cells. This study might provide some understanding of the biological function and molecular mechanism of HLCDG1 gene.     

Inhibitory effect of extract of Oratosquilla on migration and vasculogenic mimicry in human nasopharyngeal carcinoma cell line in vitro

AIM: To study the inhibitory effect of the extract of Oratosquilla (EOS) on the migration and vasculogenic mimicry in human poorly differentiated nasopharyngeal carcinoma cell line CNE-2.METHODS: CNE-2 cells were cultured in the medium with different concentrations of EOS (0 mg/L, 125 mg/L, 250 mg/L and 500 mg/L). The migration of CNE-2 cells and the formation of tube-like structures (TLSs) by CNE-2 cells were determined with wound healing assay and in vitro anti-angiogenesis test, respectively. The formation of TLSs by CNE-2 cells and their structural characteristics were observed by anti-angiogenesis test on the Matrigel. The protein expression of fascin 1 and vascular endothelial growth factor (VEGF) was detected by Western blotting.RESULTS: Compared with control group, EOS significantly decreased the migration velocity of CNE-2 cells in a dose-dependent manner. CNE-2 cells formed TLSs on the Matrigel, and the formation of TLSs by CNE-2 cells was inhibited by EOS in a dose-dependent manner. The expression of fascin 1 and VEGF in CNE-2 cells was also decreased after treatment with EOS. A positive correlation between the expression of fascin 1/VEGF and the formation of TLSs by CNE-2 cells was observed.CONCLUSION: CNE-2 cells form TLSs on the Matrigel, and EOS inhibits the migration and vasculogenic mimicry of CNE-2 cells, which are related with down-regulating the expression of fascin 1 and VEGF in CNE-2 cells.     

Construction of FAK-shRNA retroviral vector and screening of stable HCC-LM3 cell line with persistent knockdown of FAK

AIM: To construct a recombinant retroviral vector of short interfering RNA targeting focal adhesion kinase (FAK) gene and to establish a cell line with stable knockdown of FAK.METHODS: The oligonucleotides that transcribed to short hairpin RNA (shRNA) targeting FAK gene were synthesized in vitro, cloned into retroviral vector pSuper.retro and transfected into Phoenix cell line. The stable clones were screened and high-titer virus was produced. The human hepatocellular carcinoma cell line HCC-LM3 was infected with the virus-rich supernatant. The stable LM3 cell line, which showed significantly to silence FAK and associated proteins, was selected by puromycin.RESULTS: The recombinant retroviral vector was successfully constructed. Persistent knockdown of FAK in the LM3 cell line infected with the supernatant containing the retrovirus was confirmed by Western blotting. Down-regulation of FAK resulted in the inhibition of p-Akt and p-MAPK1/2 expression and led to decreased migration and invasion of the cells. The cell cycle was blocked at G₀/G₁ phase, and apoptosis was increased. The proliferation rate also decreased significantly.CONCLUSION: FAK-shRNA virus generated by recombinant retroviral vector pSuper-FAK can inhibit the protein expression of FAK and phosphorylation of Akt and MAPK1/2 in HCC-LM3 cells. Down-regulation of FAK shows a significant impact on biological behaviors of tumor cells.     

Over-expression of SATB1 mediates invasion and metastasis of nasopharyngeal carcinoma cells through epithelial-mesenchymal transition

AIM:To analyze the high expression of special AT-rich sequence-binding protein 1 (SATB1) in nasopharyngeal carcinoma (NPC) and its role in tumor invasion and metastasis. METHODS:The method of immunohistochemistry was used to detect the expression of SATB1 and epithelial-mesenchymal transition (EMT)-related molecules E-cadherin and vimentin in 76 cases of NPC and 61 cases of nasopharyngeal chronic inflammation (NPI), and the correlations of over-expression of SATB1 with NPC patients' clinical parameters as well as the expression of E-cadherin and vi-mentin were analyzed. Variously differentiated NPC cell lines CNE1, CNE2Z and C666-1 were cultured in vitro, and then SATB1-overexpressing cell line was screened. After interfering with SATB1 expression by siRNA, the expression of EMT-related molecules and the change of cell invasiveness were analyzed. RESULTS:The expression of SATB1 in the nasopharyngeal tissue was dominantly localized in the nuclei. The positive rate of SATB1 in NPC group was significantly higher than that in NPI group (P<0.01). E-cadherin was membrane-positive in NPI epithelial cells, while membrane E-cadherin in NPC was decreased but cytoplasmic expression was increased. The positive expression rate of membrane E-cadherin in NPI was significantly higher than that of NPC (P<0.01). Vimentin was localized in cytoplasm and negative in NPI epithelial cells, but the positive rate in NPC parenchymal cells was significant higher than that in NPI (P<0.01). The high expression of SATB1 in NPC was not related to the patents' sex, age, clinical classification and N classification, but positively correlated with T and M classification (P<0.05). Besides, high expression of SATB1 was positively correlated with vi-mentin in NPC tissues (r=0.358, P=0.009). SATB1 expression in NPC cell lines was negatively correlated with the levels of cell differentiation. Knockdown of SATB1 expression in C666-1 cells with siRNA was accompanied by an increase in E-cadherin and a decrease in vimentin levels, as well as a decrease in cell invasiveness. CONCLUSION:High expression of SATB1 promotes the clinical progress of NPC through EMT mechanism.