Increased CCT5 expression is a potential unfavourable factor promoting the growth of nasopharyngeal carcinoma.

OBJECTIVE: Chaperonin containing TCP1 subunit 5 (CCT5) encodes the CCT5 protein subunit of chaperonin-containing TCP-1 (CCT/TRiC) complex, and is shown to be upregulated in tumour pathogenesis. The study aim was to investigate the differential expression of CCT5 between nasopharyngeal carcinoma (NPC) and noncancerous nasopharyngeal tissues, and the correlation between CCT5 expression and clinicopathological parameters/prognosis in patients with NPC. METHODS: Microarray assay data were evaluated for differential expression between NPC and noncancerous nasopharyngeal tissues. CCT5 expression in NPC and noncancerous nasopharyngeal tissues was determined at mRNA and protein levels by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. Relationships between CCT5 expression in NPC, clinical parameters, and prognosis were statistically analysed. CCT5-mediated cell proliferation was assessed using EdU and cell counting kit-8. Western blot and co-immunoprecipitation were utilized to explore E3 ubiquitin-protein ligase parkin (PARK2)-induced degradation of CCT5. RESULTS: Microarray data showed CCT5 levels to be significantly increased in NPC versus noncancerous nasopharyngeal tissues, which was confirmed by qRT-PCR and immunohistochemical assays. Increased CCT5 protein levels positively correlated with tumour size, tumour recurrence, and clinical stage, and inversely correlated with patient's overall survival. Multivariate Cox regression analysis showed that enhanced CCT5 protein expression is an independent prognostic factor for patients with NPC. Overexpression of CCT5 markedly induced NPC cell proliferation. Finally, PARK2, as a suppressive E3 ubiquitin-ligase enzyme, was shown to bind CCT5 and induce degradation in NPC. CONCLUSIONS: Increased CCT5 may be an unfavourable factor promoting NPC growth. Binding of PARK2 to CCT5 was associated with CCT5 degradation, suggesting that PARK2 is an upstream negative modulator in NPC.

Mechanism of luteolin induces ferroptosis in nasopharyngeal carcinoma cells.

Nasopharyngeal carcinoma (NPC) originates from the nasopharynx epithelium, and luteolin is recognized as an important anti-cancer agent. This study investigated the effects of luteolin on ferroptosis in NPC cells. NPC cells were cultured and exposed to varying concentrations of luteolin. Cell viability, malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, glutathione (GSH) levels, Fe2+ concentration, and glutathione peroxidase 4 (GPX4) protein level were assessed. Additionally, SRY-related high-mobility-group box 4 (SOX4) expression was measured. Subsequently, the binding of SOX4 to the growth differentiation factor-15 (GDF15) promoter and GDF15 mRNA levels were evaluated. The impact of the SOX4/GDF15 axis on luteolin-induced ferroptosis in NPC cells was assayed. Luteolin treatment induced cell ferroptosis, evidenced by decreased cell viability, increased MDA and Fe2+ levels, and reduced SOD, GSH, and GPX4 levels. Furthermore, luteolin downregulated SOX4 expression, while overexpression of SOX4 reversed luteolin's pro-ferroptotic effects in NPC cells. SOX4 was found to up-regulate GDF15 transcription by directly binding to its promoter. Conversely, overexpression of GDF15 mitigated the ferroptotic effects induced by luteolin in NPC cells. Therefore, luteolin induces ferroptosis in NPC cells via modulation of the SOX4/GDF15 axis. In conclusion, luteolin reduces the binding of SOX4 to the GDF15 promoter by suppressing SOX4 expression, thereby down-regulating GDF15 transcription levels and inducing ferroptosis in NPC cells.

B7-H3 promotes nasopharyngeal carcinoma progression by regulating CD8+ T cell exhaustion.

BACKGROUND: B7-H3 protein is an important regulator of the adaptive immune response in human tumorigenesis. 4-1BB is a co-stimulatory receptor expressed on activated CD8+ T cells, and regulates T cell immunity. Here, we investigated the role of B7-H3 in the growth and invasion of nasopharyngeal carcinoma (NPC) and the effect of its interaction with 4-1BB on tumor immunity. METHODS: Short hairpin (sh) RNA was designed to knock down B7-H3 expression in NPC cells. NPC cells with stable knockdown of B7-H3 were established and injected into nude mice. The effects of B7-H3 on cell proliferation, apoptosis, and epithelial-to-mesenchymal transition (EMT) were detected by the CCK8 assay, flow cytometry, TUNEL assay, and western blot analysis. The migration and invasion abilities were determined using the Transwell assay and scratch assay. Co-immunoprecipitation (Co-IP) assays were performed to study the interaction between B7-H3 and 4-1BB. Anti-4-1BB antibody was used in a co-culture system and xenograft mice to study the effect of 4-1BB on NPC development. RESULTS: NPC cells transfected with sh-B7-H3 showed a higher rate of apoptosis, slower growth rate, impaired migration, and less EMT in vitro. Xenograft mice with stable knockout of B7-H3 had lower tumor burdens, and the stripped tumors had lower rates of cell proliferation, higher rates of apoptosis, and less EMT in vivo. Additionally, decreased B7-H3 expression was positively correlated with interferon-γ, tumor necrosis factor-α, and 4-1BB+CD8+ tumor-infiltrating lymphocytes. Co-IP studies showed that B7-H3 interacts with 4-1BB. Also, the inhibitory effects of sh-B7-H3 on NPC tumor growth, invasion, and tumor immunity could be alleviated by the anti-4-1BB antibody both in vivo and in vitro. CONCLUSION: Our findings suggest that B7-H3 may accelerate tumor growth, tumor cell invasion, and EMT, and interact with 4-1BB to produce CD8+ T cell exhaustion that inhibits tumor immunity. B7-H3 might serve as a novel target for treating NPC.

[Dihydroartemisinin enhances sensitivity of nasopharyngeal carcinoma HNE1/DDP cells to cisplatin-induced apoptosis by promoting ROS production].

OBJECTIVE: To investigate the effect of dihydroartemisinin (DHA) for enhancing the inhibitory effect of cisplatin (DDP) on DDP-resistant nasopharyngeal carcinoma cell line HNE1/DDP and explore the mechanism. METHODS: CCK-8 method was used to assess the survival rate of HNE1/DDP cells treated with DHA (0, 5, 10, 20, 40, 80, and 160 µmol/L) and DDP (0, 4, 8, 16, 32, 64, 128 µmol/L) for 24 or 48 h, and the combination index of DHA and DDP was calculated using Compusyn software. HNE1/DDP cells treated with DHA, DDP, or their combination for 24 h were examined for cell viability, proliferation and colony formation ability using CCK-8, EdU and colony-forming assays. Flow cytometry was used to detect cell apoptosis and intracellular reactive oxygen species (ROS). The expression levels of apoptosis-related proteins cleaved PARP, cleaved caspase-9 and cleaved caspase-3 were detected by Western blotting. The effects of N-acetyl-cysteine (a ROS inhibitor) on proliferation and apoptosis of HNE1/DDP cells with combined treatment with DHA and DDP were analyzed. RESULTS: Different concentrations of DHA and DDP alone both significantly inhibited the viability of HNE1/DDP cells. The combination index of DHA (5 µmol/L) combined with DDP (8, 16, 32, 64, 128 µmol/L) were all below 1. Compared with DHA or DDP alone, their combined treatment more potently decreased the cell viability, colony-forming ability and the number of EdU-positive cells, and significantly increased the apoptotic rate, intracellular ROS level, and the expression levels of cleaved PARP, cleaved caspase-9 and cleaved caspase-3 in HNE1/DDP cells. N-acetyl-cysteine pretreatment obviously attenuated the inhibitory effect on proliferation and apoptosis-inducing effect of DHA combined with DDP in HNE1/DDP cells (P<0.01). CONCLUSION: DHA enhances the growth-inhibitory and apoptosis-inducing effect of DDP on HNE1/DDP cells possibly by promoting accumulation of intracellular ROS.

Aquaporin-3 is down-regulated by LMP1 in nasopharyngeal carcinoma cells to regulate cell migration and affect EBV latent infection.

Epstein-Barr virus (EBV) infection has a strong correlation with the development of nasopharyngeal carcinoma (NPC). Aquaporin 3 (AQP3), a member of the aquaporin family, plays an important role in tumor development, especially in epithelial-mesenchymal transition. In this study, the expression of AQP3 in EBV-positive NPC cells was significantly lower than that in EBV-negative NPC cells. Western blot and qRT-PCR analysis showed that LMP1 down-regulated the expression of AQP3 by activating the ERK pathway. Cell biology experiments have confirmed that AQP3 affects the development of tumor by promoting cell migration and proliferation in NPC cells. In addition, AQP3 can promote the lysis of EBV in EBV-positive NPC cells. The inhibition of AQP3 expression by EBV through LMP1 may be one of the mechanisms by which EBV maintains latent infection-induced tumor progression.

Ac4C modification of lncRNA SIMALR promotes nasopharyngeal carcinoma progression through activating eEF1A2 to facilitate ITGB4/ITGA6 translation.

The dysregulation of long non-coding RNAs (lncRNAs) are involved in regulating tumor progression in multiple manner. However, little is known about whether lncRNA is involved in the translation regulation of proteins. Here, we identified that the suppressor of inflammatory macrophage apoptosis lncRNA (SIMALR) was highly expressed in nasopharyngeal carcinoma (NPC) tissues by analyzing the lncRNA microarray. Clinically, the high expression of SIMALR served as an independent predictor for inferior prognosis in NPC patients. SIMALR functioned as an oncogenic lncRNA that promoted the proliferation and metastasis of NPC cells in vitro and in vivo. Mechanistically, SIMALR served as a critical accelerator of protein synthesis by binding to eEF1A2 (eukaryotic translation elongation factor 1 alpha 2), one of the most crucial regulators in the translation machinery of the eukaryotic cells, and enhancing its endogenous GTPase activity. Furthermore, SIMALR mediated the activation of eEF1A2 phosphorylation to accelerate the translation of ITGB4/ITGA6, ultimately promoting the malignant phenotype of NPC cells. In addition, N-acetyltransferase 10 (NAT10) enhanced the stability of SIMALR and caused its overexpression in NPC through the N4-acetylcytidine (ac4C) modification. In sum, our results illustrate SIMALR functions as an accelerator for protein translation and highlight the oncogenic role of NAT10-SIMALR-eEF1A2-ITGB4/6 axis in NPC.

Immunoinhibitory effects of hypoxia-driven reprogramming of EGR1hi and EGR3 positive B cells in the nasopharyngeal carcinoma microenvironment.

Regulatory B (Breg) cells is a type of immune cell that exhibit immunosuppressive behavior within the tumor microenvironment. However, the differentiation and regulatory mechanisms of these Breg cells remain unexplored. Single-cell transcriptome sequencing analysis of human nasopharyngeal carcinoma (NPC) revealed a significant enrichment of B cell subset characterized by high expression of EGR1 and EGR3 in the tumor microenvironment. Notably, in the hypoxic microenvironment, these B cells induce MAPK pathway activation, subsequently triggering the activation of transcription factors EGR1 and EGR3, which further modulate the expression of immunosuppressive factors like TGFB1 and IL10. In transplant experiments using primary B cells induced under hypoxia and co-transplanted with cancer cells, a significant increase in tumor growth was observed. Mechanism experiments demonstrated that EGR1hi and EGR3+ B cells further activate the maturation and immunosuppressive function of Treg cells through the secretion of IL16 and TNF-α. Hence, this study identifies the key transcription factors EGR1 and EGR3 as essential regulators and elucidates the differentiation of Breg cells under hypoxic conditions.

ALYREF promotes the metastasis of nasopharyngeal carcinoma by increasing the stability of NOTCH1 mRNA.

Approximately 70% of treatment failures in nasopharyngeal carcinoma (NPC) patients are attributed to distant metastasis, yet the underlying mechanisms remain unclear. RNA 5-methylcytosine (m5C) is an emerging regulatory modification that controls gene expression and plays a critical role in tumor progression. However, there is little information on the potential roles of RNA m5C modification in NPC metastasis. In this study, we found that the m5C reader Aly/REF export factor (ALYREF) is significantly upregulated in NPC, whereby its high expression is associated with metastasis and poor prognosis. ALYREF overexpression was found to promote tumor metastasis of NPC cells in vitro and in vivo. Mechanistically, m5C-modified NOTCH1 mRNA was identified as a target of ALYREF. Moreover, ALYREF was found to upregulate NOTCH1 expression by enhancing its RNA stability in an m5C modification-dependent manner, thereby promoting the activation of the NOTCH signaling pathway and facilitating NPC metastasis. Overall, our data reveal the crucial role of ALYREF in NPC metastasis and provide a potential therapeutic target for NPC.

Tumor-associated macrophage-derived itaconic acid contributes to nasopharyngeal carcinoma progression by promoting immune escape via TET2.

Nasopharyngeal carcinoma (NPC) is a malignant tumor of epithelial origin in head and neck with high incidence rate in South China, Southeast Asia and North Africa. The intervention of tumor-associated macrophages (Mφs) (TAMs)-mediated immunosuppression is a potential therapeutic strategy against tumor metastasis, but the exact mechanisms of TAM-mediated immunosuppression in nasopharyngeal carcinoma are unclear. Furthermore, how TAM affects the occurrence and development of nasopharyngeal carcinoma through metabolism is rarely involved. In this work, we revealed that NPC cells promoted M2-type Mφ polarization and elevated itaconic acid (ITA) release. Also, TAMs facilitated NPC cell proliferation, migration, and invasion through immune response gene 1 (IRG1)-catalyzed ITA production. Then, IRG1-mediated ITA production in TAMs repressed the killing of CD8+ T cells, induced M2-type polarization of TAMs, and reduced the phagocytosis of TAMs. Moreover, we demonstrated ITA played a tumor immunosuppressive role by binding and dampening ten-eleven translocation-2 (TET2) expression. Finally, we proved that ITA promotes NPC growth by facilitating immune escape in CD34+ hematopoietic stem cell humanized mice. In Conclusion, TAM-derived ITA facilitated NPC progression by enhancing immune escape through targeting TET2, highlighting that interfering with the metabolic pathway of ITA may be a potential strategy for NPC treatment.

Isoliquiritigenin diminishes invasiveness of human nasopharyngeal carcinoma cells associating with inhibition of MMP-2 expression and STAT3 signalling.

Nasopharyngeal carcinoma (NPC) is prevalent in Asia and exhibits highly metastatic characteristics, leading to uncontrolled disease progression. Isoliquiritigenin (ISL) have attracted attention due to their diverse biological and pharmacological properties, including anticancer activities. However, the impact of ISL on the invasive and migratory ability of NPC remains poorly understood. Hence, this study aimed to investigate the in vitro anti-metastatic effects of ISL on NPC cells and elucidate the underlying signalling pathways. Human NPC cell NPC-39 and NPC-BM were utilized as cell models. Migratory and invasive capabilities were evaluated through wound healing and invasion assays, respectively. Gelatin zymography was employed to demonstrate matrix metalloproteinase-2 (MMP-2) activity, while western blotting was conducted to analyse protein expression levels and explore signalling cascades. Overexpression of signal transducer and activator of transcription 3 (STAT3) was carried out by transduction of STAT3-expressing vector. Our findings revealed that ISL effectively suppressed the migration and invasion of NPC cells. Gelatin zymography and Western blotting assays demonstrated that ISL treatment led to a reduction in MMP-2 enzyme activity and protein expression. Investigation of signalling cascades revealed that ISL treatment resulted in the inhibition of STAT3 phosphorylation. Moreover, overexpression of STAT3 restored the migratory ability of NPC cells in the presence of ISL. Collectively, these findings indicate that ISL inhibits the migration and invasion of NPC cells associating with MMP-2 downregulation through suppressing STAT3 activation. This suggests that ISL has an anti-metastatic effect on NPC cells and has potential therapeutic benefit for NPC treatment.

HDAC6-mediated deacetylation of FLOT2 maintains stability and tumorigenic function of FLOT2 in nasopharyngeal carcinoma. / HDAC6通过介导FLOT2åŽ»ä¹™é °åŒ–ç»´æŒå ¶åœ¨é¼»å’½ç™Œä¸­çš„ç¨³å®šåŠä¿ƒç˜¤ä½œç”¨.

OBJECTIVES: Flotillin-2 (FLOT2) is a prototypical oncogenic and a potential target for cancer therapy. However, strategies for targeting FLOT2 remain undefined. Post-translational modifications are crucial for regulating protein stability, function, and localization. Understanding the mechanisms and roles of post-translational modifications is key to developing targeted therapies. This study aims to investigate the regulation and function of lysine acetylation of FLOT2 in nasopharyngeal carcinoma, providing new insights for targeting FLOT2 in cancer intervention. METHODS: The PhosphoSitePlus database was used to analyze the lysine acetylation sites of FLOT2, and a lysine acetylation site mutation of FLOT2 [FLOT2 (K211R)] was constructed. Nasopharyngeal carcinoma cells were treated with histone deacetylase (HDAC) inhibitor trichostatin A (TSA) and Sirt family deacetylase inhibitor nicotinamide (NAM). TSA-treated human embryonic kidney (HEK)-293T were transfected with FLOT2 mutant plasmids. Co-immunoprecipitation (Co-IP) was used to detect total acetylation levels of FLOT2 and the effects of specific lysine (K) site mutations on FLOT2 acetylation. Western blotting was used to detect FLOT2/FLAG-FLOT2 protein expression in TSA-treated nasopharyngeal carcinoma cells transfected with FLOT mutant plasmids, and real-time reverse transcription PCR (real-time RT-PCR) was used to detect FLOT2 mRNA expression. Nasopharyngeal carcinoma cells were treated with TSA combined with MG132 or chloroquine (CQ) to analyze FLOT2 protein expression. Cycloheximide (CHX) was used to treat HEK-293T cells transfected with FLAG-FLOT2 (WT) or FLAG-FLOT2(K211R) plasmids to assess protein degradation rates. The BioGrid database was used to identify potential interactions between FLOT2 and HDAC6, which were validated by Co-IP. HEK-293T cells were co-transfected with FLAG-FLOT2 (WT)/FLAG-FLOT2 (K211R) and Vector/HDAC6 plasmids, and grouped into FLAG-FLOT2 (WT)+Vector, FLAG-FLOT2 (WT)+HDAC6, FLAG-FLOT2 (K211R)+Vector, and FLAG-FLOT2 (K211R)+HDAC6 to analyze the impact of K211R mutation on total lysine acetylation levels. In 6-0B cells, overexpression of FLOT2 (WT) and FLOT2 (K211R) was performed, and the biological functions of FLOT2 acetylation site mutants were assessed using cell counting kit-8 (CCK-8), colony formation, and Transwell invasion assays. RESULTS: The PhosphoSitePlus database indicated that FLOT2 has an acetylation modification at the K211 site. Co-IP confirmed significant acetylation of FLOT2, with TSA significantly increasing overall FLOT2 acetylation levels, while NAM had no effect. Mutation at the K211 site significantly reduced overall FLOT2 acetylation, unaffected by TSA. TSA decreased FLOT2 protein expression in nasopharyngeal carcinoma cells without affecting FLOT2 mRNA levels or FLOT2 (K211R) protein expression in transfected cells. The degradation rate of FLOT2 (K211R) protein was significantly slower than that of FLOT2 (WT). The proteasome inhibitor MG132 prevented TSA-induced FLOT2 degradation, while the lysosome inhibitor CQ did not. BioGrid data suggested a potential interaction between FLOT2 and HDAC6, confirmed by Co-IP. Knockdown of HDAC6 in nasopharyngeal carcinoma cells significantly increased FLOT2 acetylation; co-transfection of HDAC6 and FLAG-FLOT2 (WT) significantly decreased total lysine acetylation levels, whereas co-transfection of HDAC6 and FLAG-FLOT2 (K211R) had no effect. Knockdown of HDAC6 significantly reduced FLOT2 protein levels without affecting mRNA levels. MG132 prevented HDAC6-knockdown-induced FLOT2 degradation. Knockdown of HDAC6 significantly accelerated FLOT2 degradation. Nasopharyngeal carcinoma cells transfected with FLOT2 (K211R) showed significantly higher proliferation and invasion than those transfected with FLOT2 (WT). CONCLUSIONS: The K211 site of FLOT2 undergoes acetylation modification, and HDAC6 mediates deacetylation at this site, inhibiting proteasomal degradation of FLOT2 and maintaining its stability and tumor-promoting function in nasopharyngeal carcinoma.

Mechanism of salidroside in tumor suppression through the miRNA-mRNA signaling axis. / 红景天苷通过miRNA-mRNA信号轴抑制肿瘤的机制.

With the rapid development of traditional Chinese medicine and the continuous discovery of various anticancer effects of salidroside (sal), it is known that sal inhibits tumor proliferation, invasion and migration by inducing apoptosis and autophagy, regulating the cell cycle, modulating the tumor microenvironment, and controlling cancer-related signaling pathways and molecules. The microRNA (miRNA)-mRNA signaling axis can regulate the expression of target mRNAs by altering miRNA expression, thereby affecting the growth cycle, proliferation, and metabolism of cancer cells. Studies have shown that sal can influence the occurrence and progression of various malignant tumors through the miRNA-mRNA signaling axis, inhibiting the progression of lung cancer, gastric cancer, and nasopharyngeal carcinoma, with a notable time and dose dependence in its antitumor effects. Summarizing the specific mechanism of sal regulating miRNA-mRNA signaling axis to inhibit tumors in recent years can provide a new theoretical basis, diagnosis, and therapeutic methods for the research on prevention and treatment of tumors.

Baseline SUVmax is correlated with tumor hypoxia and patient outcomes in nasopharyngeal carcinoma.

To evaluate the prognostic significance of the maximum standardized uptake value (SUVmax) in nasopharyngeal carcinoma (NPC), establish a gene signature that correlates with SUVmax, and explore the underlying biological behaviors associated with these correlations for the prediction of clinical outcomes. A cohort of 726 patients with NPC was examined to identify correlations between SUVmax and various clinical variables. RNA sequencing was performed to identify genes related to SUVmax, and these genes were used to develop an SUV signature. Additionally, transcriptome enrichment analysis was conducted to investigate the potential biological behaviors underlying the observed correlations. Higher SUVmax was associated with an increased tumor burden and worse prognosis. The SUV signature, which consisted of 10 genes, was positively correlated with SUVmax, and it predicted worse survival outcomes. This signature was highly expressed in malignant epithelial cells and associated with hypoxia and resistance to radiotherapy. Additionally, the signature was negatively correlated with immune function. SUVmax is a valuable prognostic indicator in NPC, with higher values predicting worse outcomes. The SUV signature offers further prognostic insights, linking glucose metabolism to tumor aggressiveness, treatment resistance, and immune function, and it could represent a potential biomarker for NPC.

LncRNA BC200 promotes the development of EBV-associated nasopharyngeal carcinoma by competitively binding to miR-6834-5p to upregulate TYMS expression.

Nasopharyngeal carcinoma (NPC) is closely related to Epstein-Barr virus (EBV) infection. Long noncoding RNAs (lncRNAs) play important roles in cancers. However, the molecular mechanism underlying the roles of lncRNAs in EBV-associated NPC remains largely unclear. In this study, we confirmed that the expression of the lncRNA brain cytoplasmic 200 (BC200) was significantly increased in EBV-infected NPC cells and tissues. BC200 facilitated the growth and migration of NPC cells, suggesting that it participated in NPC progression by functioning as an oncogene. Mechanistically, BC200 was found to act as a ceRNA by sponging and inhibiting miR-6834-5p. Thymidylate synthetase (TYMS), whose high expression was reported to be an independent indicator of poor prognosis in NPC via an unknown mechanism, was identified as a target gene of miR-6834-5p in the present study. BC200 upregulated TYMS expression in a manner that depends on miR-6834-5p. TYMS was abnormally upregulated in EBV-positive NPC cells and tissues, and its ectopic expression contributed to the proliferation and migration of NPC cells. This study highlights the role of lncRNA BC200, which is upregulated by EBV, in promoting the development of NPC, suggesting that BC200-mediated ceRNA network may be valuable biomarkers for the diagnosis and treatment of EBV-associated NPC.

Establishment of a visualized mouse orthotopic xenograft model of nasopharyngeal carcinoma.

Mouse orthotopic xenograft tumor models are commonly employed in studies investigating the mechanisms underlying the development and progression of tumors and their preclinical treatment. However, the unavailability of mature and visualized orthotopic xenograft models of nasopharyngeal carcinoma limits the development of treatment strategies for this cancer. The aim of this study was to provide a simple and reliable method for building an orthotopic xenograft model of nasopharyngeal carcinoma. Human nasopharyngeal carcinoma (C666-1-luc) cells, stably expressing the firefly luciferase gene, were injected subcutaneously into the right axilla of BALB/C nude mice. Four weeks later, the resulting subcutaneous tumors were cut into small blocks and grafted into the nasopharynx of immunodeficient BALB/C nude mice to induce tumor formation. Tumor growth was monitored by bioluminescence imaging and small animal magnetic resonance imaging (MRI). The expression of histological and immunological antigens associated with orthotopic xenograft nasopharyngeal carcinoma was analyzed by tissue section analysis and immunohistochemistry (IHC). A visualized orthotopic xenograft nasopharyngeal carcinoma model was successfully developed in this study. Luminescence signal detection, micro-MRI, and hematoxylin and eosin staining revealed the successful growth of tumors in the nasopharynx of the nude mice. Moreover, IHC analysis detected cytokeratin (CK), CK5/6, P40, and P63 expression in the orthotopic tumors, consistent with the reported expression of these antigens in human nasopharyngeal tumors. This study established a reproducible, visual, and less lethal orthotopic xenograft model of nasopharyngeal carcinoma, providing a platform for preclinical research.

LncRNA HOTAIRM1 promotes radioresistance in nasopharyngeal carcinoma by modulating FTO acetylation-dependent alternative splicing of CD44.

BACKGROUND: Radiotherapy is the primary treatment for patients with nasopharyngeal carcinoma (NPC); however, almost 20% of patients experience treatment failure due to radioresistance. Therefore, understanding the mechanisms of radioresistance is imperative. HOTAIRM1 is deregulated in various human cancers, yet its role in NPC radioresistance are largely unclear. METHODS: This study investigated the association between HOTAIRM1 and radioresistance using CCK8, flow cytometry, and comet assays. Additionally, xenograft mice and patient-derived xenografts (PDX) models were employed to elucidate the biological functions of HOTAIRM1, and transcriptomic RNA sequencing was utilized to identify its target genes. RESULTS: Our study revealed an upregulation of HOTAIRM1 levels in radioresistant NPC cell lines and tissues. Furthermore, a positive correlation was noted between high HOTAIRM1 expression and increased NPC cell proliferation, reduced apoptosis, G2/M cell cycle arrest, and diminished cellular DNA damage following radiotherapy. HOTAIRM1 modulates the acetylation and stability of the FTO protein, and inhibiting FTO elevates the m6A methylation level of CD44 precursor transcripts in NPC cells. Additionally, silencing the m6A reading protein YTHDC1 was found to increase the expression of CD44V. HOTAIRM1 enhances NPC cell resistance to ferroptosis and irradiation through the HOTAIRM1-FTO-YTHDC1-CD44 axis. Mechanistically, HOTAIRM1 interacts with the FTO protein and induces m6A demethylation of the CD44 transcript. The absence of m6A modification in the CD44 transcript prevents its recognition by YTHDC1, resulting in the transition from CD44S to CD44V. An abundance of CD44V suppresses ferroptosis induced by irradiation and contributes to NPC radioresistance. CONCLUSIONS: In conclusion, the results in this study support the idea that HOTAIRM1 stimulates CD44 alternative splicing via FTO-mediated demethylation, thereby attenuating ferroptosis induced by irradiation and promoting NPC radioresistance.

Differential expression of host oncogenes in human papillomavirus-associated nasopharyngeal and cervical epithelial cancers.

Human papillomavirus (HPV)-related cervical and nasopharyngeal cancers differ in molecular mechanisms underlying the oncogenic processes. The disparity may be attributed to differential expression of oncoproteins. The current study investigated the host oncogenes expression pattern in HPV-associated cervical and nasopharyngeal cancer. Formalin-fixed paraffin-embedded tissues originating from the nasopharyngeal and cervical regions were screened using Hematoxylin and Eosin staining. Genomic DNA and total RNA were extracted from confirmed cancer biopsies and non-cancer tissues (NC). HPV was detected by PCR using MY09/GP5+/6+ primers. Protein expression levels of AKT, IQGAP1, and MMP16 in HPV-infected cancers and controls were determined by immunohistochemistry. RT-qPCR was used to profile mRNAs of the oncogenes. AKT and IQGAP1 proteins were highly expressed in the epithelial cancers compared with the non-cancer tissues (p < 0.05). IQGAP1 and MMP16 mRNAs level was significantly higher in the cancers than in the NC (p < 0.05), but not AKT mRNA levels. MMP16 protein was ubiquitously expressed in all tissues. AKT mRNA level was significantly elevated in CC compared with NPC (p < 0.001). However, the difference in AKT, IQGAP1 and MMP16 proteins level between CC and NPC was not significant (p > 0.05). The oncoproteins expression level between the HPV-positive and HPV-negative cancer biopsies showed no significant difference (p < 0.05). Current study reports AKT but not IQGAP1 and MMP16 mRNAs differentially expression in cervical and nasopharyngeal cancers, independent of HPV infection status.

Primary and Orthotopic Murine Models of Nasopharyngeal Carcinoma Reveal Molecular Mechanisms Underlying its Malignant Progression.

Nasopharyngeal carcinoma (NPC), a squamous cell carcinoma originating in the nasopharynx, is a leading malignancy in south China and other south and east Asia areas. It is frequently associated with Epstein-Barr virus (EBV) infection, while there are also some NPC patients without EBV infection. Here, it is shown that the EBV+ (EBV positive) and EBV- (EBV negative) NPCs contain both shared and distinct genetic abnormalities, among the latter are increased mutations in TP53. To investigate the functional roles of NPC-associated genetic alterations, primary, orthotopic, and genetically defined NPC models were developed in mice, a key tool missed in the field. These models, initiated with gene-edited organoids of normal nasopharyngeal epithelium, faithfully recapitulated the pathological features of human disease. With these models, it is found that Trp53 and Cdkn2a deficiency are crucial for NPC initiation and progression. And latent membrane protein1 (LMP1), an EBV-coding oncoprotein, significantly promoted the distal metastasis. Further, loss of TGFBR2, which is frequently disrupted both in EBV- and EBV+ NPCs, dramatically accelerated the progression and lung metastasis of NPC probably by altering tumor microenvironment. Taken together, this work establishes a platform to dissect the genetic mechanisms underlying NPC pathogenesis and might be of value for future translational studies.

PLUNC inhibits invasion and metastasis in nasopharyngeal carcinoma by inhibiting NLRP3 inflammasome activation.

Nasopharyngeal carcinoma (NPC) is a malignant tumor that occurs in the nasopharynx. Palate, lung, and nasal epithelium clone (PLUNC) has been identified as an early secreted protein that is specifically expressed in the nasopharynx. The aim of this study was to determine the role and mechanism of PLUNC in NPC. We used mRNA sequencing (seq) combined with ribosome-nascent chain complex (RNC)-seq to determine the biological role of PLUNC. The expression of epithelial-to-mesenchymal transition (EMT)-related molecules was detected by western blotting. Then, cell migration and invasion were detected by wound healing and Transwell chamber assays. NPC cells were injected into the tail vein of nude mice to explore the biological role of PLUNC in vivo. The sequencing results showed that PLUNC inhibited the progression of NPC and its expression was correlated with that of NOD-like receptors. Experiments confirmed that PLUNC inhibited the invasion and metastasis of NPC cells by promoting the ubiquitination degradation of NLRP3. PLUNC overexpression in combination with the treatment by MCC950, an inhibitor of NLRP3 inflammasome activation, was most effective in inhibiting NPC invasion and metastasis. In vivo experiments also confirmed that the combination of PLUNC overexpression and MCC950 treatment effectively inhibited the lung metastasis of NPC cells. In summary, our research suggested that PLUNC inhibited the invasion and metastasis of NPC by inhibiting NLRP3 inflammasome activation, and targeting the PLUNC-NLRP3 inflammasome axis could provide a new strategy for the diagnosis and treatment of NPC patients.

The Roles of mTOR Signaling in Nasopharyngeal Carcinoma: From Pathogenesis to Therapy

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy caused by cancer of the mucosal epithelial cells of the nasopharynx. Most patients with NPC present with distant metastases and treatment resistance, both of which challenge current anti-tumour drugs. The mammalian target of the rapamycin (mTOR) signalling pathway is one of the most highly activated signalling pathways in NPC and plays an important role in various cellular activities. Dysfunction of mTOR and related signalling pathways induces tumour metabolism and growth. In this review, we summarize current evidence to evaluate the potential mechanisms by which mTOR is implicated in NPC. It was found that activating mTOR and its upstream and downstream signalling can promote tumor growth and survival of NPC. It is possible that EMT and autophagy regulated by cellular mTOR signalling activities may be implicated in the metastases and radioresistance of NPC.