Functional Roles of JNK and p38 MAPK Signaling in Nasopharyngeal Carcinoma.

c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) family members integrate signals that affect proliferation, differentiation, survival, and migration in a cell context- and cell type-specific way. JNK and p38 MAPK activities are found upregulated in nasopharyngeal carcinoma (NPC). Studies have shown that activation of JNK and p38 MAPK signaling can promote NPC oncogenesis by mechanisms within the cancer cells and interactions with the tumor microenvironment. They regulate multiple transcription activities and contribute to tumor-promoting processes, ranging from cell proliferation to apoptosis, inflammation, metastasis, and angiogenesis. Current literature suggests that JNK and p38 MAPK activation may exert pro-tumorigenic functions in NPC, though the underlying mechanisms are not well documented and have yet to be fully explored. Here, we aim to provide a narrative review of JNK and p38 MAPK pathways in human cancers with a primary focus on NPC. We also discuss the potential therapeutic agents that could be used to target JNK and p38 MAPK signaling in NPC, along with perspectives for future works. We aim to inspire future studies further delineating JNK and p38 MAPK signaling in NPC oncogenesis which might offer important insights for better strategies in diagnosis, prognosis, and treatment decision-making in NPC patients.

Acylglycerol kinase promotes paclitaxel resistance in nasopharyngeal carcinoma cells by regulating FOXM1 via the JAK2/STAT3 pathway.

OBJECTIVE: Drug resistance is an important factor that impedes the treatment of nasopharyngeal cancer (NPC). Acylglycerol kinase (AGK) has been found to be overexpressed in NPC and correlates with poor prognosis. Our objective was to demonstrate the effect of AGK on paclitaxel resistance in NPC and determine the underlying mechanisms. METHODS: MTT assay was employed to determine the IC50 of paclitaxel in NPC cells after different treatments. Flow cytometry assays were employed to evaluate cell apoptosis. RT-qPCR and Western blot assays were used to detect alterations in mRNA and protein expression, respectively. Luciferase assays and chromatin immunoprecipitation (ChIP) assays were used to determine the relationship between and the regulatory effect of STAT3 on the promoter of FOXM1. RESULTS: AGK was elevated in paclitaxel-resistant NPC cells, and knockdown of AGK suppressed the resistance of CNE1-TR and CNE2-TR cells to paclitaxel. Moreover, upregulation of FOXM1 rescued the effects of AGK knockdown. Furthermore, the JAK2/STAT3 signalling pathway was overactivated in CNE1-TR and CNE2-TR cells, and knockdown of AGK suppressed JAK2/STAT3 signalling. STAT3 was verified to bind to and activate the promoter region of FOXM1. An in vivo tumour xenograft assay also verified that AGK knockdown inhibited tumour growth and mitigated paclitaxel resistance by regulating the JAK2/STAT3/FOXM1 axis. CONCLUSION: AGK levels were increased in paclitaxel-resistant NPC cells. AGK activates JAK2/STAT3 signalling, thus promoting FOXM1 transcription and eventually enhancing the drug resistance of NPC cells.

Human Caspase 12 Enhances NF-κB Activity through Activation of IKK in Nasopharyngeal Carcinoma Cells.

Human nasopharyngeal carcinoma (NPC) is a highly invasive cancer associated with proinflammation. Caspase-12 (Casp12), an inflammatory caspase, is implicated in the regulation of NF-κB-mediated cellular invasion via the modulation of the IκBα protein in NPC cells. However, the effect mechanisms of Casp12 need to be elucidated. NPC cells were transfected with the full length of human Casp12 cDNA (pC12) and the effect of human Casp12 (hCasp12) on the NF-κB activity was investigated. We found ectopic expression of hCasp12 increased the NF-κB activity accompanied by an increased p-IκBα expression and a decreased IκBα expression. Treatment of BMS, a specific IKK inhibitor, and pC12-transfected cells markedly decreased the NF-κB activity and ameliorated the expression level of IκBα reduced by hCasp12. Co-immunoprecipitation assays validated the physical interaction of hCasp12 with IKKα/ß, but not with NEMO. Furthermore, the NF-κB activity of ΔCasp12-Q (a mutated catalytic of hCasp12) transfected cells was concentration-dependently induced, but lower than that of hCasp12-transfected cells. Importantly, the hCasp12-mediated NF-kB activity was enhanced by TNFα stimulation. That indicated a role of the catalytic motif of hCasp12 in the regulation of the NF-κB activity. This study indicated hCasp12 activated the NF-κB pathway through the activation of IKK in human NPC cells.

High expression of heme oxygenase-1 in tumor-associated macrophages characterizes a poor-prognosis subtype in nasopharyngeal carcinoma.

Tumor-associated macrophages (TAMs) are important components of the tumor microenvironment, which are characterized by pro-tumor M2 phenotype and correlate with poor survival of nasopharyngeal carcinoma (NPC). Heme oxygenase-1 (HO-1) plays a crucial role in macrophage polarization toward M2 phenotype, but its prognosis significance in NPC has been rarely determined. To gain insights into the HO-1 expression profile and to determine the clinical significance of HO-1 in NPC, we performed immunohistochemistry analyses in 126 NPC specimens. CD163, a highly specific marker of M2 macrophages, was used as a surrogate for the polarization state of TAMs. Our results showed that high expression of HO-1 and CD163 were detected in TAMs for 57.9% (73/126) and 61.9% (78/126) of the studied patients, and both of them were significantly associated with worse survival. Additionally, a significant correlation between the intensities of HO-1 and CD163 was identified, and HO-1 exhibited a superior ability in predicting survival compared with CD163. Our study revealed for the first time that overexpression of HO-1 characterized a poor-prognosis subtype in NPC. Individualized therapy targeting HO-1 might serve as a promising treatment modality for NPC.

Parallel genome-wide RNAi screens identify lymphocyte-specific protein tyrosine kinase (LCK) as a targetable vulnerability of cell proliferation and chemoresistance in nasopharyngeal carcinoma.

Despite recent in advances in the management of nasopharyngeal carcinoma (NPC), development of targeted therapy remains challenging particularly in patients with recurrent or metastatic disease. To search for clinically relevant targets for the treatment of NPC, we carried out parallel genome-wide functional screens to identified essential genes that are required for NPC cells proliferation and cisplatin resistance. We identified lymphocyte-specific protein tyrosine kinase (LCK) as a key vulnerability of both proliferation and cisplatin resistance. Depletion of endogenous LCK or treatment of cells with LCK inhibitor induced tumor-specific cell death and synergized cisplatin sensitivity in EBV-positive C666-1 and EBV-negative SUNE1 cells. Further analyses demonstrated that LCK is regulating the proliferation and cisplatin resistance through activation of signal transducer and activator of transcription 5 (STAT5). Taken together, our study provides a molecular basis for targeting LCK and STAT5 signaling as potential druggable targets for the management of NPC.

Rab1A promotes cancer metastasis and radioresistance through activating GSK-3ß/Wnt/ß-catenin signaling in nasopharyngeal carcinoma.

Many articles have reported that Rab1A was overexpressed in a variety of human cancers and involved in tumor progression and metastasis. However, the biological function and molecular mechanism of Rab1A in nasopharyngeal carcinoma (NPC) remained unknown until now. Here we found that Rab1A overexpression is a common event and was positively associated with distant metastasis and poor prognosis of NPC patients. Functionally, Rab1A depletion inhibited the migration and EMT phenotype of NPC cells, whereas Rab1A overexpression led to the opposite effect. Furthermore, we reveal an important role for Rab1A protein in the induction of radioresistance via regulating homologous recombination (HR) signaling pathway. Mechanistically, Rab1A activated Wnt/ß-catenin signaling by inhibiting the activity of GSK-3ß via phosphorylation at Ser9. Then Wnt/ß-catenin signaling induced NPC cells radioresistance and metastasis through nuclear translocation of ß-catenin and transcription upregulation of HR pathway-related and EMT-related genes expression. In general, this study shows that Rab1A may serve as a potential biomarker for predicting prognosis in NPC patients. Targeting Rab1A and Wnt/ß-catenin signaling may hold promise to overcome NPC radioresistance.

Targeting fatty acid synthase sensitizes human nasopharyngeal carcinoma cells to radiation via downregulating frizzled class receptor 10.

Objective: Our aim was to test the hypothesis that fatty acid synthase (FASN) expression contributes to radioresistance of nasopharyngeal carcinoma (NPC) cells and that inhibiting FASN enhances radiosensitivity. Methods: Targeting FASN using epigallocatechin gallate (EGCG) or RNA interference in NPC cell lines that overexpress endogenous FASN was performed to determine their effects on cellular response to radiation in vitro using MTT and colony formation assays, and in vivo using xenograft animal models. Western blot, immunohistochemistry, real-time PCR arrays, and real-time RT-PCR were used to determine the relationship between FASN and frizzled class receptor 10 (FZD10) expression. FZD10 knockdown and overexpression were used to determine its role in mediating FASN function in cellular response to radiation. Immunohistochemical staining was used to determine FASN and FZD10 expressions in human NPC tissues, followed by analysis of their association with the overall survival of patients. Results: FASN knockdown or inhibition significantly enhanced radiosensitivity of NPC cells, both in vitro and in vivo. There was a positive association between FASN and FZD10 expression in NPC cell lines grown as monolayers or xenografts, as well as human tissues. FASN knockdown reduced FZD10 expression, and rescue of FZD10 expression abolished FASN knockdown-induced enhancement of radiosensitivity. FASN and FZD10 were both negatively associated with overall survival of NPC patients. Conclusions: FASN contributes to radioresistance, possibly via FZD10 in NPC cells. Both FZD10 and FASN expressions were associated with poor outcomes of NPC patients. EGCG may sensitize radioresistance by inhibiting FASN and may possibly be developed as a radiosensitizer for better treatment of NPCs.

Tetrandrine sensitizes nasopharyngeal carcinoma cells to irradiation by inducing autophagy and inhibiting MEK/ERK pathway.

Radioresistance was the main reason for local recurrence and metastasis of nasopharyngeal carcinoma. Tetrandrine is reported as an antitumor drug via inducing cell cycle arrest and apoptosis. In this study, the radiosensitization effects of maximum noncytotoxic doses of tetrandrine in nasopharyngeal carcinoma were analyzed both in vitro and in vivo, using MTT assay, western blot, TUNEL, and HE staining. It was found that the maximum dose of tetrandrine inhibited the phosphorylation of ERK and MEK induced by irradiation, and significantly enhanced irradiation-induced cell growth inhibition in nasopharyngeal carcinoma cells CNE1, CNE2, and C666-1. The ERK activator and overexpression of ERK reversed the radiosensitization effect of tetrandrine. About 50 mg/kg of tetrandrine which was used as the maximum noncytotoxic dose of tetrandrine in vivo, enhanced the radiosensitivity of the xenograft tumor and increased the apoptosis rate of the xenograft tumor cells caused by irradiation, while did not raise the side effect of the treatment. Moreover, tetrandrine increased autophagy in nasopharyngeal carcinoma cells. These results suggested that the maximum noncytotoxic dose of tetrandrine sensitized nasopharyngeal carcinoma to irradiation by inhibiting MEK/ERK pathway and inducing autophagy.

Glutamine synthetase facilitates cancer cells to recover from irradiation-induced G2/M arrest.

Resistance to radiation of cancer cells can be either intrinsic or acquired, leading to treatment failure. In response to DNA damage caused by IR, cancer cells are arrested in cell cycle showing limited proliferation and increased apoptosis. However, radiation-resistant cells are able to overcome the cell cycle block and proceed to proliferation, for which the detailed mechanism remains to be elucidated. In the present study, we showed that radioresistant cells exhibited a recoverable G2/M phase during prolonged cell cycle and manifested lower apoptosis rate and more colony formation. RNA-seq analysis revealed that glutamine synthetase (GS, GLUL) gene was highly expressed in radioresistant cancer cells in comparison with the parental cells, which was in accordance with the G2/M arrest after ionizing radiation. Knocking out of GS in radioresistant cells resulted in a delayed G2/M recovery and lowered proliferation rate after ionizing radiation treatment, which was accompanied with increased inhibitory phosphorylation of CDK1 at Y15 and downregulated Cdc25B, a dual specific phosphatase of CDK1. Moreover, there was an enhanced complex formation of CDK1 and Cyclin B1 when the cells were rescued by re-introducing GS. In vivo, knocking down of GS significantly sensitized CNE2-R xenografts to RT in mice. In this study, we demonstrate a novel role of glutamine synthetase independent of metabolic function in promoting recovery from G2/M arrest caused by ionizing radiation, thus, causing cancer cell resistance to radiotherapy.

Matrix metalloproteinase 1 promotes tumorigenesis and inhibits the sensitivity to 5-fluorouracil of nasopharyngeal carcinoma.

PROBLEM AND OBJECT: 5-fluorouracil (5-FU) is a pyrimidine-like antimetabolite. It has been widely used in human cancer therapies; however, the drug sensitivity can be very low and the survival outcome can be very poor dependent on tumor types and individual heterogeneity. This research was aimed to study the effects of matrix metalloproteinase 1 (MMP1) gene on nasopharyngeal carcinoma (NPC) cell proliferation, viability, invasiveness, apoptosis, and sensitivity to 5-FU. METHODS: Bioinformatics method was used to screen out the differentiated expressed genes in nasopharyngeal carcinomas compared with normal nasopharyngeal epithelial tissues. qRT-PCR was used to determine the expression of MMP1 mRNA, and western blot was used to determine the protein expression of MMP1, thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD). Colony foci formation assay, CCK8 assay, and BrdU incorporation assay were used to study the cell proliferation. Transwell invasion assay was carried out to determine cell invasion. Flow cytometry and caspase 3/7 activation assay were used to detect cell apoptosis. RESULTS: MMP1 gene was the most significantly upregulated gene in nasopharyngeal carcinomas according to the bioinformatics analysis. And the upregulation of MMP1 gene was confirmed in both NPC tissues and cell lines using RT-QPCR and western blot technique. When 5-FU was not a player, the forced overexpression of MMP1 gene led to enhanced growth and invasion of CNE1 and HNE1 cell lines, whereas MMP1 gene knockdown resulted in the opposite outcome. When 5-FU was added, MMP1 gene knockdown led to significantly suppressed cell proliferation and enhanced cell apoptosis. Also, MMP1 gene knockdown caused significantly lower level of TS and DPD enzymes. CONCLUSION: Not only the knockdown of MMP1 gene led to suppressed proliferation and invasion but also increased the sensitivity to 5-FU of CNE1 and HNE1 cells. Our results provided convincing evidence that MMP1 gene knockdown could offer a favorable sensitivity approach for NPC with 5-FU treatment.

[Clinical differences between primary nasopharyngeal NK/T-cell lymphoma and primary nasal cavity NK/T-cell lymphoma with nasopharynx extension].

Objective: To investigate the clinical and prognostic differences between primary nasopharyngeal natural killer (NK)/T-cell lymphoma (NP NKTCL) and extranodal NK/T-cell lymphoma of the nasal cavity with nasopharynx extension (N-NP NKTCL). Methods: A total of 89 patients with NP NKTCL and 113 patients with N-NP NKTCL from January 2000 to June 2015 were retrospectively analyzed. Clinical and pathological features, treatment responses and prognosis were compared between the two groups. Results: NP NKTCL patients showed similar clinicopathological features with those with N-NP NKTCL, except that the former had a relative low proportion of elevated lactate dehydrogenase (LDH) levels (28.1% vs. 41.6%; P=0.001). Both of two groups presented with high proportion of cervical lymph node involvement (55.1% and 42.5%; P=0.076). The 5-year overall survival (OS) rates in these two groups were 63.2% and 54.6%, respectively, whereas 5-year progress-free survival (PFS) rates were 50.7% and 45.6%, respectively. For the patients with stage Ⅰ and Ⅱ, the 5-year OS and PFS rates in these two groups were 68.8% and 55.7% as well as 55.6% and 47.2%, respectively. These were no statistically significant differences between two groups (all P>0.05). The complete response (CR) rate after initial chemotherapy in NP NKTCL group was 43.8%, which was significant higher than that of 19.6% in N-NP NKTCL group (P=0.006). Additionally, the CR rate after primary radiotherapy was 63.4% and 62.7%, respectively (P=0.629). The NP NKTCL patients with stage Ⅰ and Ⅱ who accepted radiotherapy with or without chemotherapy had similar survival times with chemotherapy alone, showing the 5-year OS rates of 70.5% and 33.3% (P=0.238), as well as the 5-year PFS rates of 56.7% and 33.3%, respectively (P=0.431). Similar results were found in N-NP NKTCL group, the 5-year OS rates for patients with radiotherapy with or without chemotherapy and chemotherapy alone were 57.4% and 33.3% (P=0.246), while the 5-year PFS rates were 49.3% and 16.7% (P=0.177), respectively. Besides, the relapse pattern of NP NKTCL and N-NP NKTCL groups was also similar, mainly involving the distant extra-nodal organs followed by lymph nodes. Conclusion: The patients with N-NP NKTCL and NP NKTCL showed similar clinical and prognostic features, however, the initial response to chemotherapy was different.

High NEK2 confers to poor prognosis and contributes to cisplatin-based chemotherapy resistance in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a common malignant tumor in southern China and Southeast Asia, but the molecular mechanism of its pathogenesis is poorly understood. Our previous work demonstrated that NEK2 is overexpressed in multiple cancers. However, how NEK2 involves in NPC development remains to be elucidated. In this study, we firstly identified NEK2, located at +1q32-q33, a late event in NPC pathogenesis, overexpressed in the stage III-IV and paired sequential recurrent patients with NPC by immunohistochemistry. Furthermore, Kaplan-Meier analysis indicated high NEK2 conferred an inferior overall survival in NPC. In addition, cisplatin experiments with cell counting kit-8, colony formation, and a xenograft mice model of NPC demonstrated that NEK2 contributed to proliferation and cisplatin resistance in vitro and in vivo. On the contrary, downregulation of NEK2 by short hairpin RNA inhibited NPC cell growth and increased the sensitivity of cisplatin treatment in vitro. Thus, increased expression of NEK2 protein could not be predicted for poor survival but used as a novel biomarker for recurrence of NPC. Targeting NEK2 has the potential to eradicate the cisplatin-based chemotherapy resistant NPC cells.

Erianin induces cell apoptosis through ERK pathway in human nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is one of the most common cancers in areas of Southeast Asia, such as Taiwan, and North Africa. The treatments of NPC, including radiotherapy and chemotherapy, were effective, but they also caused some severe side effects. Erianin, a natural product derived from Dendrobium, was proved to have anti-cancer effect in hepatoma, melanoma, non-small-cell lung carcinoma, myelogenous leukemia, breast cancer, and osteosarcoma. HYPOTHESIS/PURPOSE: According to previous research, we hypothesized that erianin inhibits cancer cell growth through apoptotic mechanisms. This study aimed to determine whether Erianin has an anti-NPC effect and what mechanisms were involved. METHODS AND RESULTS: The result showed that erianin significantly increased activation of apoptosis in NPC cell lines (NPC-039 and NPC-BM) and arrest the cell cycle obviously through mitochondrial membrane alternation, death receptors activation, and caspase-3, -8, -9 activation. Phosphorylated ERK1/2 was also decreased in erianin-treated NPC cell with dose-dependent manner, and the result was thought to promote apoptosis. Furthermore, the increased rate of apoptotic cells with erianin plus it's inhibitors (U) was also revealed in this study. CONCLUSION: In conclusion, this is the first research to identify the anti-NPC effect of erianin via the apoptosis mechanism. Erianin was a promising natural agent against nasopharyngeal carcinoma.

MiR-30e-5p inhibits proliferation and metastasis of nasopharyngeal carcinoma cells by target-ing USP22.

OBJECTIVE: To investigate the effects of miR-30e-5p on the proliferation, invasion and migration of nasopharyngeal carcinoma (NPC) cells, as well as its underlying mechanism. PATIENTS AND METHODS: We detected the expressions of miR-30e-5p in NPC tissues, adjacent normal tissues, NPC cells (5-8F cells) and control cells (293T cells) by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). The target gene of miR-30e-5p was predicted by online software and ubiquitin-specific peptidase 22 (USP22) was screened out. Luciferase reporter gene assay was performed after NPC cells were co-transfected miR-30e-5p mimics or miR-30e-5p inhibitor and mutant-type or wild-type USP22, respectively. Expressions of miR-30e-5p and USP22 in 5-8F cells were detected by qRT-PCR and Western blotting. The proliferation of 5-8F cells was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, and the invasion and migration abilities were detected by transwell assay. The activation of the epithelial-mesenchymal transition (EMT) was analyzed by detecting expressions of EMT-associated proteins (E-cadherin and Vimentin) in NPC cells. RESULTS: Expression level of miR-30e-5p was remarkably reduced, while USP22 expression was elevated in NPC tissues and cells compared with the controls. Molecular mechanism analysis con-firmed that miR-30e-5p could negatively regulate mRNA and protein levels of USP22 by binding to its specific sequence of 3'UTR. Subsequent experiments showed that USP22 knockdown resulting from up-regulation of miR-30e-5p could inhibit proliferation, invasion, migration, and EMT in 5-8F cells. CONCLUSIONS: MiR-30e-5p was lowly expressed in NPC by targeting USP22, suggesting that miR-30e-5p could be used as a potential therapeutic target for NPC.

Efficient Translation of Epstein-Barr Virus (EBV) DNA Polymerase Contributes to the Enhanced Lytic Replication Phenotype of M81 EBV.

Epstein-Barr virus (EBV) is linked to the development of both lymphoid and epithelial malignancies worldwide. The M81 strain of EBV, isolated from a Chinese patient with nasopharyngeal carcinoma (NPC), demonstrates spontaneous lytic replication and high-titer virus production in comparison to the prototype B95-8 EBV strain. Genetic comparisons of M81 and B95-8 EBVs were previously been performed in order to determine if the hyperlytic property of M81 is associated with sequence differences in essential lytic genes. EBV SM is an RNA-binding protein expressed during early lytic replication that is essential for virus production. We compared the functions of M81 SM and B95-8 SM and demonstrate that polymorphisms in SM do not contribute to the lytic phenotype of M81 EBV. However, the expression level of the EBV DNA polymerase protein was much higher in M81- than in B95-8-infected cells. The relative deficiency in the expression of B95-8 DNA polymerase was related to the B95-8 genome deletion, which truncates the BALF5 3' untranslated region (UTR). Similarly, the insertion of bacmid DNA into the widely used recombinant B95-8 bacmid creates an inefficient BALF5 3' UTR. We further showed that the while SM is required for and facilitates the efficient expression of both M81 and B95-8 mRNAs regardless of the 3' UTR, the BALF5 3' UTR sequence is important for BALF5 protein translation. These data indicate that the enhanced lytic replication and virus production of M81 compared to those of B95-8 are partly due to the robust translation of EBV DNA polymerase required for viral DNA replication due to a more efficient BALF5 3' UTR in M81.IMPORTANCE Epstein-Barr virus (EBV) infects more than 90% of the human population, but the incidence of EBV-associated tumors varies greatly in different parts of the world. Thus, understanding the connection between genetic polymorphisms from patient isolates of EBV, gene expression phenotypes, and disease is important and may help in developing antiviral therapy. This study examines potential causes of the enhanced lytic replicative properties of M81 EBV isolated from a nasopharyngeal carcinoma (NPC) patient and provides new evidence for the role of the BALF5 gene 3' UTR sequence in DNA polymerase protein expression during lytic replication. Variation in the gene structure of the DNA polymerase gene may therefore contribute to lytic virus reactivation and pathogenesis.

EBV-encoded miRNAs target ATM-mediated response in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a highly invasive epithelial malignancy that is prevalent in southern China and Southeast Asia. It is consistently associated with latent Epstein-Barr virus (EBV) infection. In NPC, miR-BARTs, the EBV-encoded miRNAs derived from BamH1-A rightward transcripts, are abundantly expressed and contribute to cancer development by targeting various cellular and viral genes. In this study, we establish a comprehensive transcriptional profile of EBV-encoded miRNAs in a panel of NPC patient-derived xenografts and an EBV-positive NPC cell line by small RNA sequencing. Among the 40 miR-BARTs, predominant expression of 22 miRNAs was consistently detected in these tumors. Among the abundantly expressed EBV-miRNAs, BART5-5p, BART7-3p, BART9-3p, and BART14-3p could negatively regulate the expression of a key DNA double-strand break (DSB) repair gene, ataxia telangiectasia mutated (ATM), by binding to multiple sites on its 3'-UTR. Notably, the expression of these four miR-BARTs represented more than 10% of all EBV-encoded miRNAs in tumor cells, while downregulation of ATM expression was commonly detected in all of our tested sequenced samples. In addition, downregulation of ATM was also observed in primary NPC tissues in both qRT-PCR (16 NP and 45 NPC cases) and immunohistochemical staining (35 NP and 46 NPC cases) analysis. Modulation of ATM expression by BART5-5p, BART7-3p, BART9-3p, and BART14-3p was demonstrated in the transient transfection assays. These findings suggest that EBV uses miRNA machinery as a key mechanism to control the ATM signaling pathway in NPC cells. By suppressing these endogenous miR-BARTs in EBV-positive NPC cells, we further demonstrated the novel function of miR-BARTs in inhibiting Zta-induced lytic reactivation. These findings imply that the four viral miRNAs work co-operatively to modulate ATM activity in response to DNA damage and to maintain viral latency, contributing to the tumorigenesis of NPC. © 2017 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Low expression of nm23-H1 associates with poor survival of nasopharyngeal carcinoma patients: A prisma-compliant meta-analysis.

BACKGROUND: Developing a new reliable prognostic marker to predict the prognosis and supply better and more suitable therapy for patients with nasopharyngeal carcinoma (NPC) is urgent. Therefore, we performed this systematic review of the literature with meta-analysis to clarify and explore the associate expression of nm23-H1 with prognosis of NPC patients. METHODS: Literature research in Cochrane Library, PubMed, and EMBASE was performed up to July 2016. Eligible case-control studies of associate expression of nm23-H1 with prognosis of NPC patients were included. RESULTS: Nine studies met our inclusion criteria and were finally included for the analysis, involving 861 participants. Our meta-analysis revealed that the low expression of nm23-H1 in NPC was: RR = 2.13, 95% CI 1.15-3.95 and R = 2.56, 95% CI 2.03-3.22; and poorer overall survival (OS) rate was 3-year OS rate: RR: 0.55; 95% CI: 0.45-0.67 and 5-year OS rate: RR: 0.60; 95% CI: 0.52-0.69. Furthermore, the statistical significance was constant irrespective of different NPC subtypes. CONCLUSION: The low expression of nm23-H1 is associated with poorer prognosis in patients with NPC, suggesting that it is a prognostic factor and potential biomarker for survival in NPC.

Clinicopathological and prognostic significance of GPx2 protein expression in nasopharyngeal carcinoma.

OBJECTIVE: This study was designed to evaluate the relation between GPx2 (glutathione peroxidase 2) expressions and clinicopathological features as well as prognosis of patients with nasopharyngeal carcinoma (NPC). METHODS: A total of 89 cases of NPC were investigated to examine the immunohistochemical expression of GPx2. Fourteen pairs of NPC and the control samples were analyzed respectively by qRT-PCR and Western blot. The correlations of GPx2 expressions with the clinicopathologic features and the prognosis of NPC patients were also analyzed. RESULTS: The expression of GPx2 in NPC tissues was elevated immunohistochemically when compared with normal nasopharyngeal tissues (P< 0.05). The mRNA expression of GPx2 in carcinoma tissues was highly elevated compared with the control tissues (P< 0.05). GPx2 protein in carcinoma tissues was also over expressed than in control tissues (P< 0.05). Also GPx2 expression was significantly higher in the late clinical stage (P= 0.02). While there was no significant association between GPx2 expression and patient age, sex, T-stage, N-stage and the metastasis. CONCLUSIONS: GPx2 may play an important role in the development of nasopharyngeal carcinoma. Furthermore, GPx2 may serve as a prognostic biomarker for NPC patient.

Prognostic impact of pretherapeutic gamma-glutamyltransferase on patients with nasopharyngeal carcinoma.

BACKGROUND: Gamma-glutamyltransferase (GGT) is a membrane-bound enzyme involved in the metabolism of glutathione. Studies suggested that GGT played an important role in the tumor development, progression, invasion and drug resistance and prognosis. The association between GGT and prognosis of patients with nasopharyngeal carcinoma (NPC) was unknown. This study was conducted to investigate the association of pretherapeutic serum level of GGT with clinical-pathological parameters and survival in patients with NPC. METHODS: Two hundred and twenty-two patients with NPC were recruited in this study and were stratified into two GGT risk groups (≤ 34.5 U/L, > 34.5 U/L). The association of pretherapeutic serum GGT levels with clinical-pathological parameters was examined. Univariate and multivariate survival analyses were performed. FINDINGS: The pretherapeutic serum level of GGT was not associated with gender, age, pathology, T stage, N stage, TNM stage, chemotherapy or radiotherapy in patients with NPC. Patients in the high-risk GGT group had a poorer survival than the low-risk GGT group (3-year overall survival, 74.2% vs. 50.2%, P = 0.001; 3-year progression-free survival, 76.4% vs. 47.1%, P < 0.001; 3-year loco-regional relapse-free survival, 76.4% vs. 51.3%, P < 0.001; 3-year distant metastasis-free survival, 89.5% vs. 66.4%, P < 0.001). Multivariate analysis suggested that patients in the high-risk GGT group had 2.117 (95% confidence interval [CI], 1.225 ∼ 3.659, P = 0.007) times the risk of death, 2.836 (95% CI, 1.765 ∼ 4.557, P < 0.001) times the risk of progression, 2.551 (95% CI, 1.573 ∼ 4.138, P < 0.001) times the risk of relapse, and 3.331 (95% CI, 1.676 ∼ 6.622, P < 0.001) times the risk of metastasis compared with those in the low-risk GGT group. CONCLUSION: The pretherapeutic serum level of GGT might serve as a novel independent prognostic factor for overall-survival, progression-free survival, loco-regional relapse-free survival and distant metastasis-free survival in patients with NPC.