Nasopharyngeal Carcinoma Cells Research Articles

Nasopharyngeal Carcinoma Cell Lines: Reliable Alternatives to Primary Nasopharyngeal Cells?

Nasopharyngeal carcinoma (NPC) is a type of cancer that originates from the mucosal lining of the nasopharynx and can invade and spread. Although contemporary chemoradiotherapy effectively manages the disease locally, there are still challenges with locoregional recurrence and distant failure. Therefore, it is crucial to have a deeper understanding of the molecular basis of NPC cell movement in order to develop a more effective treatment and to improve patient survival rates. Cancer cell line models are invaluable in studying health and disease and it is not surprising that they play a critical role in NPC research. Consequently, scientists have established around 80 immortalized human NPC lines that are commonly used as in vitro models. However, over the years, it has been observed that many cell lines are misidentified or contaminated by other cells. This cross-contamination leads to the creation of false cell lines that no longer match the original donor. In this commentary, we discuss the impact of misidentified NPC cell lines on the scientific literature. We found 1159 articles from 2000 to 2023 that used NPC cell lines contaminated with HeLa cells. Alarmingly, the number of publications and citations using these contaminated cell lines continued to increase, even after information about the contamination was officially published. These articles were most commonly published in the fields of oncology, pharmacology, and experimental medicine research. These findings highlight the importance of science policy and support the need for journals to require authentication testing before publication.

Abstract 1109: LINC01770 stabilizes TEAD1 expression to mediates nasopharyngeal cancer radiation resistance rendering tumor cells vulnerable to ferroptosis

Abstract Background: Long noncoding RNAs (lncRNAs) regulate various essential biological processes, including cell proliferation, differentiation, apoptosis, migration, and invasion. However, in nasopharyngeal carcinoma (NPC), the clinical significance and mechanisms of lncRNAs in malignant progression are unknown. Methods: LINC01770 expression was determined using quantitative real-time reverse transcription PCR, and its prognostic value was evaluated using Kaplan-Meier survival analysis. RNA sequencing and bioinformatic analysis were used to determine the potential function of LINC01770, and its biological effects were investigated using in vitro and in vivo experiments. Mass spectrometry-coupled RNA pull-down assays and western blotting identified LINC01770 interacting proteins, followed by confirmation using RNA immunoprecipitation (RIP) assays. Ferroptosis and lipid peroxidation were detected using flow cytometry. Results: LINC01770 was overexpressed in NPC tissues according to microarray screening. Patients with NPC showing high LINC01770 expression experienced shorter survival and worse prognosis. In vitro and in vivo experiments suggested that knockdown of LINC01770 expression significantly inhibited the proliferation, migration, and invasion of NPC cells. Sequencing and functional complementation experiments showed that LINC01770 regulates the proliferation and metastasis of NPC through TEA domain transcription factor 1 (TEAD1). Meanwhile, RIP and PCR experiments suggested that LINC01770 and TEAD1 were common targets of microRNAs miR-615-5p and miR-1293. Overexpression of LINC01770 promoted ferroptosis in vitro and in vivo through the TEAD1/Acyl-CoA synthetase long chain family member 4 (ACSL4)/transferrin receptor (TFRC) pathway. Conclusions: LINC01770 is a prognostic biomarker for NPC and participates in the regulation of TEAD1 signaling pathway through competitive binding to miRNA-615-5p and miRNA-1293, resulting in NPC metastasis and progression. Radiation resistant cells are in a delicate balance between lipid peroxidation and increased vulnerability to ferroptosis, suggesting that ferroptosis could be used to kill NPC cells and reverse their radiotherapy resistance during the malignant progression of NPC caused by high expression of LINC01770. Thus, inducing ferroptosis could be used to treat recurrent and refractory NPC. Citation Format: Qingqing Xu, Ciming Sun, Suixian Zhang, Xuan Li, Lei Chen, Ming Chen. LINC01770 stabilizes TEAD1 expression to mediates nasopharyngeal cancer radiation resistance rendering tumor cells vulnerable to ferroptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1109.

Abstract 4456: De novo pyrimidine synthesis is a druggable vulnerability for chemotherapy resistant nasopharyngeal carcinoma with wild type IDH1

Abstract Chemotherapy resistance is a major obstacle to treat nasopharyngeal carcinoma (NPC), and strategies to overcome this resistance are required. Using proteomic analysis, we found that NPC patients resistant to gemcitabine plus cisplatin (GP) induction chemotherapy were characterized by abundant metabolic pathways. NPC with high expression of wild-type isocitrate dehydrogenase 1 (wtIDH1) was hyperdependent on de novo pyrimidine nucleotide synthesis and resistant to GP. Knockdown of IDH1 augmented the inhibition of de novo pyrimidine nucleotide synthesis induced by gemcitabine and cisplatin but reversed the suppression of purine nucleotide synthesis, which leading to DNA damage caused by nucleotide pool imbalance. IDH1 facilitated transcription of dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme for de novo pyrimidine nucleotide synthesis, through promoting chromatin accessibility by ALKBH5 in an α-ketoglutaric acid dependent manner. DHODH inhibitor, BAY2402234 significantly sensitized NPC cells to gemcitabine plus cisplatin chemotherapy. Collectively, these results reveal that wtIDH1-induced increase in de novo pyrimidine nucleotide represents a metabolic vulnerability that can be exploited pharmacologically, highlighting BAY2402234 as a promising strategy to enhance the efficacy of chemotherapy against NPC. Citation Format: Yingqin Li, Yuheng Zhao, Wuqi Zhang, Chunxian Ou, Jiaxi Shen, Jun Ma. De novo pyrimidine synthesis is a druggable vulnerability for chemotherapy resistant nasopharyngeal carcinoma with wild type IDH1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4456.

Abstract 1999: DCAF7 acts as a scaffold to recruit USP10 for G3BP1 deubiquitylation and facilitates chemoresistance and metastasis in nasopharyngeal carcinoma

Abstract Though docetaxel plus cisplatin and 5-fluorouracil (TPF) induction chemotherapy becomes the standard care for locoregionally advanced nasopharyngeal carcinoma (NPC), some patients could not benefit from this therapy. The underlying mechanisms remain unclear. We found that DCAF7 was highly expressed in TPF resistant NPC patients, and promoted the cisplatin resistance and metastasis of NPC cells. Mechanistically, DCAF7 facilitates the interaction between USP10 and G3BP1, resulting in the removal of K48-linked ubiquitylation of G3BP1 at Lys76 mediated by USP10, thus preventing the degradation of G3BP1 through ubiquitin-proteasome pathway, and facilitates the stress granule (SG)-like structures formation. Moreover, knockdown of G3BP1 successfully reversed the SG-like structures formation and oncogenic effects exerted by DCAF7. Importantly, NPC patients with elevated DCAF7 expression exhibited high risks of metastasis, and is associated with a poor prognosis. This study identifies DCAF7 as a pivotal cisplatin resistance gene, and sheds light on the underlying mechanism of TPF resistance in NPC patients. The DCAF7-USP10-G3BP1 axis provides potential therapeutic targets and biomarker for NPC treatment. Citation Format: Qing-Jie Li, Xue-Liang Fang, Ying-Qin Li, Jia-Yi Lin, Cheng-Long Huang, Shi-Wei He, Sheng-Yan Huang, Jun-Yan Li, Sha Gong, Kai-Lin Chen, Na Liu, Jun Ma, Yin Zhao, Ling-Long Tang. DCAF7 acts as a scaffold to recruit USP10 for G3BP1 deubiquitylation and facilitates chemoresistance and metastasis in nasopharyngeal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1999.

Abstract 3272: PJA1 inhibits docetaxel-induced pyroptosis and results in chemoresistance in nasopharyngeal carcinoma

Abstract Background: Nasopharyngeal carcinoma (NPC) is highly prevalent in South China. More than 70% of patients are diagnosed with locoregionally advanced NPC (LA-NPC) at initial presentation, and the addition of induction chemotherapy (IC) to concurrent chemoradiotherapy is recommended for these patients. However, chemoresistance is a main reason for treatment failure in NPC patients, and the exact regulatory mechanism underlying chemoresistance in NPC remains to be elucidated. Methods: A gene expression dataset and STRING database were used to identify core module and gene that are related to the efficacy of docetaxel-cisplatin-5-fluorouracil (TPF) IC in NPC patients. In vitro and in vivo functional experiments were used to test the effects of PJA1 on docetaxel chemoresistance of NPC cells. The flow cytometric analysis, western blot, and lactate dehydrogenase (LDH) release assays were performed to determine the effects of PJA1 on GSDME-mediated cell pyroptosis. Co-immunoprecipitation, mass spectrometry, immunofluorescence staining, and ubiquitination assays were performed to explore the regulatory manners between PJA1 and PGAM5-DRP1 axis. Finally, multiplex immunofluorescence and immunohistochemical staining were used to evaluate the clinical significance of PJA1 -PGAM5-DRP1 axis in patients with NPC. Results: PJA1 was identified as a key E3 ligase of the top-ranked module ubiquitin-proteasome system dysregulation that involved in NPC chemoresistance, which was highly expressed in NPC patients with nonresponse to the TPF IC. PJA1 facilitated the docetaxel resistance of NPC cells through inhibiting the GSDME-mediated pyroptosis. Mechanistically, PJA1 promoted the degradation of the mitochondrial protein PGAM5 by increasing its K48-linked ubiquitination at K88, further increasing the phosphorylation of DRP1 at S637 and reducing the mitochondrial reactive oxygen species (ROS) production, in turn resulting in a suppressive of GSDME-mediated pyroptosis. PGAM5 knockdown fully restored the docetaxel sensitization effect of PJA1 knockdown. Moreover, RTA402, a pharmacological inhibitor of PJA1, enhanced the docetaxel sensitivity of NPC cells. Clinically, high PJA1 expression indicated resistance to TPF IC an inferior survival in NPC patients. Conclusions: Our study emphasizes the essential role of E3 ligase PJA1 in regulating chemoresistance in NPC and provides new therapeutic strategies for NPC patients based on targeting the ubiquitin-proteasome system. Citation Format: Na Liu, Ying-Qing Li, Sheng-Yan Huang. PJA1 inhibits docetaxel-induced pyroptosis and results in chemoresistance in nasopharyngeal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3272.

Abstract 1113: USP18 impairs the sensitivity of radiotherapy for nasopharyngeal carcinoma by promoting the ubiquitination and nuclear translocation of TRIM29

Abstract Radiotherapy is the main and preferred treatment for nasopharyngeal carcinoma (NPC), owing to its high sensitivity to radiation. However, there are ~20% patients suffering from tumor recurrence. Accumulating evidences show that protein ubiquitination plays a vital role in radiation caused DNA damage response. Here, we identified that the deubiquitinase USP18 is highly expressed in NPC tissues, and inversely associated with radiosensitivity of NPC cells. USP18 interacts with TRIM29 and promotes its K27-linked ubiquitination independent of its deubiquitinase activity. Further investigation reveals that USP18 acts as a scaffold to recruit the E3 ubiquitin ligase TRIM21 to directly ubiquitinate TRIM29 at Lys307, thus promoting its oligomerization and nuclear translocation, and thereby facilitates the DNA damage repair of NPC cells after irradiation. Clinically, higher expression of USP18 indicates poor response to radiotherapy and worse prognosis in NPC patients. Our findings reveal the critical role of USP18 in regulating radiosensitivity, and targeting USP18-TRIM21-TRIM29 axis maybe a novel strategy to synergize with radiotherapy for NPC patients. Citation Format: Jia-Yi Lin, Wei-Wei Zhang, Qing-Jie Li, Xue-Liang Fang, Jun-Yan Li, Shi-Wei He, Ying-Qin Li, Jun Ma, Na Liu, Yin Zhao, Rui Guo. USP18 impairs the sensitivity of radiotherapy for nasopharyngeal carcinoma by promoting the ubiquitination and nuclear translocation of TRIM29 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1113.

Hsa-miR-92b-3p Targeting FHL2 to Enhance Radiosensitivity of Nasopharyngeal Carcinoma.

Radiotherapy resistance is a major cause of treatment failure and leads to poor prognosis in nasopharyngeal carcinoma (NPC). Evidences indicate that microRNA (miRNAs) are closely associated with radiotherapy for NPC. In this study, we found that the expression level of miR-92b-3p was significantly higher in radiotherapy-sensitive NPC patients than in radiotherapy-resistant patients. High expression of miR-92b-3p was associated with good prognosis in patients with NPC, and high expression of FHL2 was associated with poor prognosis in patients with NPC. It was predicted that miR-92b-3p could directly target and bind FHL2. Overexpression of miR-92b-3p significantly inhibited FHL2 expression at the mRNA as well as protein levels, while inhibition of miR-92b-3p expression significantly upregulated FHL2 expression. Overexpression of miR-92b-3p significantly reduced proliferation and colony formation in NPC cells. Inhibition of miR-92b-3p attenuated the sensitivity of nasopharyngeal carcinoma to radiotherapy, while simultaneous inhibition of miR-92b-3p and FHL2 increased the sensitivity of NPC to radiotherapy. Our findings highlighted that miR-92b-3p is closely associated with radiotherapy sensitivity and prognosis in NPC patients and may improve the sensitivity of NPC to radiotherapy by targeting FHL2.

MiRNA-296-5p promotes the sensitivity of nasopharyngeal carcinoma cells to cisplatin via targeted inhibition of STAT3/KLF4 signaling axis

Improving drug sensitivity is an important strategy in chemotherapy of cancer and accumulating evidence indicates that miRNAs are involved in the regulation of drug sensitivity, but the specific mechanism is still unclear. Our previous study has found that miR-296-5p was significantly downregulated in nasopharyngeal carcinoma (NPC). Here, we aim to explore whether miR-296-5p is involved in regulating cisplatin sensitivity in NPC by regulating STAT3/KLF4 signaling axis. The cell proliferation and clonogenic capacity of NPC cells were evaluated by CCK8 Assay and plate colony assay, respectively. The Annexin V-FITC staining kit was used to determine and quantify the apoptotic cells using flow cytometry. The drug efflux ability of NPC cells were determined by Rhodamine 123 efflux experiment. The expression of miR-296-5p, apoptosis-related genes and protein in NPC cell lines were detected by qPCR and Western blot, respectively. Animal study was used to evaluate the sensitivity of NPC cells to DDP treatment in vivo. Our results showed that elevated miR-296-5p expression obviously promoted the sensitivity of NPC cells to DDP by inhibiting cell proliferation and clonogenic capacity, and inducing apoptosis. In addition, we found that miR-296-5p inhibited the expression of STAT3 and KLF4 in NPC cells, while overexpression of exogenous STAT3 reversed miR-296-5p-mediated enhancement in cell death of DDP-treated NPC cells. In vivo studies further confirmed that miR-296-5p promotes the sensitivity of NPC cells to DDP treatment. miRNA-296-5p enhances the drug sensitivity of nasopharyngeal carcinoma cells to cisplatin via STAT3/KLF4 signaling pathway.

Evolutionary analysis of LMP-1 genetic diversity in EBV-associated nasopharyngeal carcinoma: Bioinformatic insights into oncogenic potential

EBV latent membrane protein 1 (LMP-1) is an important oncogene involved in the induction and maintenance of EBV infection and the activation of several cell survival and proliferative pathways. The genetic diversity of LMP-1 has an important role in immunogenicity and tumorigenicity allowing escape from host cell immunity and more metastatic potential of LMP-1 variants. This study explored the evolutionary of LMP-1 in EBV-infected patients at an advanced stage of nasopharyngeal carcinoma (NPC). Detection of genetic variability in LMP-1 genes was carried out using Sanger sequencing. Bioinformatic analysis was conducted for translation and nucleotide alignment. Phylogenetic analysis was used to construct a Bayesian tree for a deeper understanding of the genetic relationships, evolutionary connections, and variations between sequences. Genetic characterization of LMP-1 in NPC patients revealed the detection of polymorphism in LMP-1 Sequences. Motifs were identified within three critical LMP-1 domains, such as PQQAT within CTAR1 and YYD within CTAR2. The presence of the JACK3 region at specific sites within CTAR3, as well as repeat regions at positions (122−132) and (133–143) within CTAR3, was also annotated. Additionally, several mutations were detected including 30 and 69 bp deletions, 33 bp repeats, and 15 bp insertion. Although LMP-1 strains appear to be genetically diverse, they are closely related to 3 reference strains: prototype B95.8, Med- 30 bp deletion, and Med + 30 bp deletion. In our study, one of the strains harboring the 30 bp deletion had both bone and bone marrow metastasis which could be attributed to the fact that LMP-1 is involved in tumor metastasis, evasion and migration of NPC cells. This study provided valuable insights into genetic variability in LMP-1 sequences of EBV in NPC patients. Further functional studies would provide a more comprehensive understanding of the molecular characteristics, epidemiology, and clinical implications of LMP-1 polymorphisms in EBV-related malignancies.

Enhancer infestation drives tumorigenic activation of inactive B compartment in Epstein-Barr virus-positive nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated malignant epithelial tumor endemic to Southern China and Southeast Asia. While previous studies have revealed a low frequency of gene mutations in NPC, its epigenomic aberrations are not fully elucidated apart from DNA hypermethylation. Epigenomic rewiring and enhancer dysregulation, such as enhancer hijacking due to genomic structural changes or extrachromosomal DNA, drive cancer progression. We conducted Hi-C, 4C-seq, ChIP-seq, and RNA-seq analyses to comprehensively elucidate the epigenome and interactome of NPC using C666-1 EBV(+)-NPC cell lines, NP69T immortalized nasopharyngeal epithelial cells, clinical NPC biopsy samples, and invitro EBV infection in HK1 and NPC-TW01 EBV(-) cell lines. In C666-1, the EBV genome significantly interacted with inactive B compartments of host cells; the significant association of EBV-interacting regions (EBVIRs) with B compartment was confirmed using clinical NPC and invitro EBV infection model. EBVIRs in C666-1 showed significantly higher levels of active histone modifications compared with NP69T. Aberrant activation of EBVIRs after EBV infection was validated using invitro EBV infection models. Within the EBVIR-overlapping topologically associating domains, 14 H3K4me3(+) genes were significantly upregulated in C666-1. Target genes of EBVIRs including PLA2G4A, PTGS2 and CITED2, interacted with the enhancers activated in EBVIRs and were highly expressed in NPC, and their knockdown significantly reduced cell proliferation. The EBV genome contributes to NPC tumorigenesis through "enhancer infestation" by interacting with the inactive B compartments of the host genome and aberrantly activating enhancers. The funds are listed in the Acknowledgements section.

MiR-2110 induced by chemically synthesized cinobufagin functions as a tumor-metastatic suppressor via targeting FGFR1 to reduce PTEN ubiquitination degradation in nasopharyngeal carcinoma.

Tumor cell metastasis is the key cause of death in patients with nasopharyngeal carcinoma (NPC). MiR-2110 was cloned and identified in Epstein-Barr virus (EBV)-positive NPC, but its role is unclear in NPC. In this study, we investigated the effect of miR-2110 on NPC metastasis and its related molecular basis. In addition, we also explored whether miR-2110 can be regulated by cinobufotalin (CB) and participate in the inhibition of CB on NPC metastasis. Bioinformatics, RT-PCR, and in situ hybridization were used to observe the expression of miR-2110 in NPC tissues and cells. Scratch, Boyden, and tail vein metastasis model of nude mouse were used to detect the effect of miR-2110 on NPC metastasis. Western blot, Co-IP, luciferase activity, colocalization of micro confocal and ubiquitination assays were used to identify the molecular mechanism of miR-2110 affecting NPC metastasis. Finally, miR-2110 induced by CB participates in CB-stimulated inhibition of NPC metastasis was explored. The data showed that increased miR-2110 significantly suppresses NPC cell migration, invasion, and metastasis. Suppressing miR-2110 markedly restored NPC cell migration and invasion. Mechanistically, miR-2110 directly targeted FGFR1 and reduced its protein expression. Decreased FGFR1 attenuated its recruitment of NEDD4, which downregulated NEDD4-induced phosphatase and tensin homolog (PTEN) ubiquitination and degradation and further increased PTEN protein stability, thereby inactivating PI3K/AKT-stimulated epithelial-mesenchymal transition signaling and ultimately suppressing NPC metastasis. Interestingly, CB, a potential new inhibitory drug for NPC metastasis, significantly induced miR-2110 expression by suppressing PI3K/AKT/c-Jun-mediated transcription inhibition. Suppression of miR-2110 significantly restored cell migration and invasion in CB-treated NPC cells. Finally, a clinical sample assay indicated that reduced miR-2110 was negatively correlated with NPC lymph node metastasis and positively related to NPC patient survival prognosis. In summary, miR-2110 is a metastatic suppressor involving in CB-induced suppression of NPC metastasis.

M 6 A reader IGF2BP1 reduces the sensitivity of nasopharyngeal carcinoma cells to Taxol by upregulation of AKT2.

Taxol is widely used in the treatment of nasopharyngeal carcinoma (NPC); nevertheless, the acquired resistance of NPC to Taxol remains one of the major obstacles in clinical treatment. In this study, we aimed to investigate the role and mechanism of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in Taxol resistance of NPC. Taxol-resistant NPC cell lines were established by exposing to gradually increased concentration of Taxol. Relative mRNA and protein levels were tested using qRT-PCR and western blot, respectively. NPC cell viability and apoptosis were assessed by cell counting kit-8 and flow cytometry analysis, respectively. Cell migration and invasion capacities were measured using transwell assay. Interaction between IGF2BP1 and AKT2 was examined by RNA immunoprecipitation assay. The N6-methyladenosine level of AKT2 was tested using methylated RNA immunoprecipitation-qPCR. IGF2BP1 expression was enhanced in Taxol-resistant NPC cell lines. Knockdown of IGF2BP1 strikingly enhanced the sensitivity of NPC cells to Taxol and repressed the migration and invasion of NPC cells. Mechanistically, IGF2BP1 elevated the expression of AKT2 by increasing its mRNA stability. Furthermore, overexpression of AKT2 reversed the inhibitory roles of IGF2BP1 silence on Taxol resistance and metastasis. Our results indicated that IGF2BP1 knockdown enhanced the sensitivity of NPC cells to Taxol by decreasing the expression of AKT2, implying that IGF2BP1 might be promising candidate target for NPC treatment.

BPIFB1, Serving as a Downstream Effector of EBV-miR-BART4, Blocks Immune Escape of Nasopharyngeal Carcinoma via Inhibiting PD-L1 Expression.

Nasopharyngeal carcinoma (NPC) is one of the most common tumors of head and neck in the Southeast Asia. PD-L1-dependent immune escape plays a critical role involved in NPC development. BPIFB1 has previously reported to take tumor-suppressive actions on NPC cell proliferation and migration. Nonetheless, the function of BPIFB1 in immune escape remains largely elusive. Expression pattern on mRNA and protein levels of target genes in NPC patients' samples and cell lines were examined by qRT-PCR, western blot, and immunohistochemistry staining, respectively. The assessment of CD8+ T-cell apoptosis and expression was determined by flow cytometry. Molecular interactions were verified using chromatin immunoprecipitation (ChIP) and luciferase reporter assay. BPIFB1 was downregulated in NPC tumor tissues, exhibiting a negative correlation of PD-L1. Overexpression of BPIFB1 significantly inhibited the expression of PD-L1, suppressing the apoptosis and enhancing the expression of CD8+ T cells. Mechanistically, BPIFB1 was found to repress the expression of STAT1, which was identified to be an upstream activator of PD-L1. Furthermore, the EBV-encoded miR-BART4 overexpressed in NPC cells could directly target and inhibit BPIFB1. This study provided a comprehensive understanding of the molecular mechanism for the upstream and downstream pathway of BPIFB1 related with immune escape, indicating a novel approach for the treatment of NPC.

A metabolic map and artificial intelligence-aided identification of nasopharyngeal carcinoma via a single-cell Raman platform.

Nasopharyngeal carcinoma (NPC) is a complex cancer influenced by various factors. This study explores the use of single-cell Raman spectroscopy as a potential diagnostic tool for investigating biomolecular changes associated with NPC carcinogenesis. Seven NPC cell lines, one immortalised nasopharyngeal epithelial cell line, six nasopharyngeal mucosa tissues and seven NPC tissue samples were analysed by performing confocal Raman spectroscopic measurements and imaging. The single-cell Raman spectral dataset was used to quantify relevant biomolecules and build machine learning classification models. Metabolomic profiles were investigated using ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS). By generating a metabolic map of seven NPC cell lines, we identified an interplay of altered metabolic processes involving nucleic acids, amino acids, lipids and sugars. The results from spatially resolved Raman maps and UPLC-MS/MS metabolomics were consistent, revealing an increase of unsaturated fatty acids in cancer cells, particularly in highly metastatic 5-8F and poorly differentiated CNE2 cells. The classification model achieved a nearly perfect classification when identifying NPC and non-NPC cells with an ROC-AUC of 0.99 and a value of 0.97 when identifying 13 tissue samples. This study unveils a complex interplay of metabolic network and highlights the potential roles of unsaturated fatty acids in NPC progression and metastasis. This renders further research to provide deeper insights into NPC pathogenesis, identify new metabolic targets and improve the efficacy of targeted therapies in NPC. Artificial intelligence-aided analysis of single-cell Raman spectra has achieved high accuracies in the classification of both cancer cells and patient tissues, paving the way for a simple, less invasive and accurate diagnostic test.

The role and molecular mechanism of NOP16 in the pathogenesis of nasopharyngeal carcinoma.

We aimed to explore the effects of NOP16 on the pathogenesis of nasopharyngeal carcinoma (NPC) and the related mechanism. In this study, the expression level of NOP16 in NPC tissues and adjacent tissues was measured by qRT-polymerase chain reaction(PCR) and immunohistochemistry (IHC)tests. In the in vitro study, the expression levels of NOP16 and RhoA/phosphatidylinositol 3-kinase(PI3K)/Akt/c-Myc and IKK/IKB/NF-κB signalling pathway-related proteins in NPC cells were measured by qRT-PCR and Western blot (WB). CCK8 assays and colony formation assays were used to detect cell proliferation. Transwell assays were used to detect the migration and invasion ability of NPC cells. Flow cytometry and WB were used to measure the level of apoptosis. For the in vivo study, NPC xenograft models were established in nude mice, and tumour weight and volume were recorded. The expression levels of NOP16 and RhoA/PI3K/Akt/c-Myc signalling pathway-related proteins and mRNAs were measured by immunofluorescence, qRT-PCR and WB experiments. In clinical samples, the results of qRT-PCR and IHC experiments showed that the expression level of NOP16 was significantly increased in NPC tissues. In the in vitro study, the results of qRT-PCR and WB experiments showed that NOP16 was significantly increased in NPC cells. The CCK8 assay, colony formation assay, transwell assay and flow cytometry results showed that knocking out NOP16 inhibited the proliferation, migration and invasion of NPC cells and increased apoptosis. WB results showed that knocking out NOP16 inhibited the RhoA/PI3K/Akt/c-Myc and IKK/IKB/NF-κB signalling pathways. These effects were reversed by 740Y-P (PI3K activator). In the in vivo study, knockdown of NOP16 reduced tumour volume and weight and inhibited the RhoA/PI3K/Akt/c-Myc signalling pathway. In conclusion, knockdown of NOP16 inhibited the proliferation, migration and invasion of NPC cells and induced apoptosis by inhibiting the RhoA/PI3K/Akt/c-Myc and IKK/IKB/NF-κB pathways, leading to the malignant phenotype of NPC.

Epstein-Barr Virus BRLF1 Induces PD-L1 Expression in Nasopharyngeal Carcinoma Cells.

Nasopharyngeal carcinoma (NPC) is a specific human malignancy with unique geographic distribution and genetic backgrounds. Although early treatment with radio-chemotherapy has been proven effective for NPC therapy, its therapeutic efficacy substantially diminishes in the late stages of this malignancy. In the tumor microenvironment of NPC, PD-L1 has been demonstrated as a critical factor in impairing T cell activation. As an etiological role for NPC development, it is found that Epstein-Barr virus (EBV) latent proteins upregulated PD-L1 expression. However, whether EBV lytic protein affects PD-L1 expression remains unclear. In this study, through monitoring the mRNA expression pattern of lytic genes and PD-L1 in EBV-positive NPC cell line NA, EBV immediately-early gene BRLF1(Rta) was found to have the potential for PD-L1 activation. Furthermore, we identified that Rta expression enhanced PD-L1 expression in mRNA and protein levels through quantitative real-time polymerase chain reaction and western blotting analysis. The luciferase reporter assay revealed that Rta expression enhanced PD-L1 promoter activity. We also demonstrated that Rta-induced PD-L1 expressions could impair interleukin 2 secretion of T cells, and this mechanism may be through ERK activation. These results displayed the importance of EBV Rta in PD-L1 expression in NPC and may give an alternative target for NPC therapy.

The role and the molecular mechanism of abietic acid in the proliferation, invasion and migration of cisplatin-resistant nasopharyngeal carcinoma cells

Objective:To investigate the effects and molecular mechanisms of abietic acid in the cell proliferation, invasion and migration of cisplatin-resistant nasopharyngeal carcinoma cells. Methods:①Cisplatin-resistant C666/DDP cell line was constructed by increasing drug concentration method. ②The effects of abietic acid on proliferation, invasion and migration of C666/DDP cells were investigated by CCK-8 method, reactive oxygen species（ROS） and mitochondrial membrane potential（MMP） level assay and subcutaneous tumorigenesis assay in nude mice to detect the effects of abietic acid on proliferation and apoptosis of C666/DDP cells in vitro and in vivo. The effect of abietic acid on the proliferation and apoptosis of C666/DDP cells in vitro and in vivo was measured by Transwell assay. ③Western blot and IHC method to detect the expression of PI3K/AKT/mTOR pathway related proteins. Results:①The IC50 of cisplatin cytotoxicity to C666-1 was about 25 μmol/L. RI=25 μmol/L /4 μmol/L=6.25, resistance was obtained, and the C666-1-DDP resistant strain was successfully constructed. ②Abietic acid promoted apoptosis and inhibited proliferation of C666/DDP cells, and showed G2/M phase block; transwell showed that abietic acid inhibited C666/DDP cell migration and invasion, increased ROS level of C666/DDP cells and decreased MMP. Transwell showed that abietic acid inhibited the migration and invasion ability of C666/DDP cells, increased the ROS level of C666/DDP cells and decreased MMP. ③Animal experiments showed that abietic acid inhibited the proliferation of cisplatin-resistant nasopharyngeal carcinoma in vivo in a concentration gradient and suppressed the expression of PI3K/AKT/mTOR signaling pathway-related proteins. Conclusion:Abietic acid inhibits proliferation, invasion and migration of cisplatin-resistant nasopharyngeal carcinoma cells by a mechanism related to inhibition of PI3K/AKT/mTOR signaling pathway.

ThermomiR-377-3p-induced suppression of Cirbp expression is required for effective elimination of cancer cells and cancer stem-like cells by hyperthermia

BackgroundIn recent years, the development of adjunctive therapeutic hyperthermia for cancer therapy has received considerable attention. However, the mechanisms underlying hyperthermia resistance are still poorly understood. In this study, we investigated the roles of cold‑inducible RNA binding protein (Cirbp) in regulating hyperthermia resistance and underlying mechanisms in nasopharyngeal carcinoma (NPC).MethodsCCK-8 assay, colony formation assay, tumor sphere formation assay, qRT-PCR, Western blot were employed to examine the effects of hyperthermia (HT), HT + oridonin(Ori) or HT + radiotherapy (RT) on the proliferation and stemness of NPC cells. RNA sequencing was applied to gain differentially expressed genes upon hyperthermia. Gain-of-function and loss-of-function experiments were used to evaluate the effects of RNAi-mediated Cirbp silencing or Cirbp overexpression on the sensitivity or resistance of NPC cells and cancer stem-like cells to hyperthermia by CCK-8 assay, colony formation assay, tumorsphere formation assay and apoptosis assay, and in subcutaneous xenograft animal model. miRNA transient transfection and luciferase reporter assay were used to demonstrate that Cirbp is a direct target of miR-377-3p. The phosphorylation levels of key members in ATM-Chk2 and ATR-Chk1 pathways were detected by Western blot.ResultsOur results firstly revealed that hyperthermia significantly attenuated the stemness of NPC cells, while combination treatment of hyperthermia and oridonin dramatically increased the killing effect on NPC cells and cancer stem cell (CSC)‑like population. Moreover, hyperthermia substantially improved the sensitivity of radiation‑resistant NPC cells and CSC‑like cells to radiotherapy. Hyperthermia noticeably suppressed Cirbp expression in NPC cells and xenograft tumor tissues. Furthermore, Cirbp inhibition remarkably boosted anti‑tumor‑killing activity of hyperthermia against NPC cells and CSC‑like cells, whereas ectopic expression of Cirbp compromised tumor‑killing effect of hyperthermia on these cells, indicating that Cirbp overexpression induces hyperthermia resistance. ThermomiR-377-3p improved the sensitivity of NPC cells and CSC‑like cells to hyperthermia in vitro by directly suppressing Cirbp expression. More importantly, our results displayed the significantly boosted sensitization of tumor xenografts to hyperthermia by Cirbp silencing in vivo, but ectopic expression of Cirbp almost completely counteracted hyperthermia-mediated tumor cell-killing effect against tumor xenografts in vivo. Mechanistically, Cirbp silencing-induced inhibition of DNA damage repair by inactivating ATM-Chk2 and ATR-Chk1 pathways, decrease in stemness and increase in cell death contributed to hyperthermic sensitization; conversely, Cirbp overexpression-induced promotion of DNA damage repair, increase in stemness and decrease in cell apoptosis contributed to hyperthermia resistance.ConclusionTaken together, these findings reveal a previously unrecognized role for Cirbp in positively regulating hyperthermia resistance and suggest that thermomiR-377-3p and its target gene Cirbp represent promising targets for therapeutic hyperthermia.

Activation of Epstein-Barr Virus' Lytic Cycle in Nasopharyngeal Carcinoma Cells by NEO212, a Conjugate of Perillyl Alcohol and Temozolomide.

The Epstein-Barr virus (EBV) is accepted as a primary risk factor for certain nasopharyngeal carcinoma (NPC) subtypes, where the virus persists in a latent stage which is thought to contribute to tumorigenesis. Current treatments are sub-optimal, and recurrence occurs in many cases. An alternative therapeutic concept is aimed at triggering the lytic cycle of EBV selectively in tumor cells as a means to add clinical benefit. While compounds able to stimulate the lytic cascade have been identified, their clinical application so far has been limited. We are developing a novel anticancer molecule, NEO212, that was generated by covalent conjugation of the alkylating agent temozolomide (TMZ) to the naturally occurring monoterpene perillyl alcohol (POH). In the current study, we investigated its potential to trigger the lytic cycle of EBV in NPC cells in vitro and in vivo. We used the established C666.1 cell line and primary patient cells derived from the brain metastasis of a patient with NPC, both of which harbored latent EBV. Upon treatment with NEO212, there was an increase in EBV proteins Zta and Ea-D, key markers of the lytic cycle, along with increased levels of CCAAT/enhancer-binding protein homologous protein (CHOP), a marker of endoplasmic reticulum (ER) stress, followed by the activation of caspases. These effects could also be confirmed in tumor tissue from mice implanted with C666.1 cells. Towards a mechanistic understanding of these events, we used siRNA-mediated knockdown of CHOP and inclusion of anti-oxidant compounds. Both approaches blocked lytic cycle induction by NEO212. Therefore, we established a sequence of events, where NEO212 caused reactive oxygen species (ROS) production, which triggered ER stress and elevated the levels of CHOP, which was required to stimulate the lytic cascade of EBV. Inclusion of the antiviral agent ganciclovir synergistically enhanced the cytotoxic impact of NEO212, pointing to a potential combination treatment for EBV-positive cancers which should be explored further. Overall, our study establishes NEO212 as a novel agent able to stimulate EBV's lytic cycle in NPC tumors, with implications for other virus-associated cancers.

CPNE1, A Potential Therapeutic Target in Nasopharyngeal Carcinoma, Affects Cell Growth and Radiation Resistance.

The increased expression of Copine 1 (CPNE1) has been observed in various cancers, which promotes cell proliferation, apoptosis, and radio resistance. However, the potential mechanism of CPNE1 in nasopharyngeal carcinoma (NPC) remains elusive. Consequently, our objective was to investigate the role of CPNE1 in regulating proliferation and radio resistance of NPC. CPNE1 expression in NPC and normal patients were obtained from Cancer Genome Atlas (TCGA) database. An elevated CPNE1 was observed in NPC patients and cells (C666-1, SUNE-1, and HNE-1). Then, C666-1 and SUNE-1 cells were subjected to si-CPNE1 under different radiations (0-8 Gy). Cell growth and proliferation were measured by CCK8 and EDU assays, which demonstrated si-CPNE1 suppressed proliferation. Colony formation was performed to detect cell viability under different radiation therapy and survival curve of cell was plotted, which indicated that CPNE1 knockdown improved cell radiosensitivity. Additionally, flow cytometry showed silence of CPNE1 enhanced apoptosis rate in radiated cells. To further investigate the mechanisms of CPNE1 regulating NPC, the expression of activated phosphate Akt (p-Akt) was assessed through western blotting. We observed elevated p-Akt in si-CPNE1 transfected C666-1 and SUNE-1 cells. In conclusion, these results demonstrated that CPNE1 expression is elevated in nasopharyngeal carcinoma cells, and its silencing could attenuate nasopharyngeal carcinoma advancement and improve radiosensitivity to radiation therapy by controlling Akt activation.