Nasopharyngeal Carcinoma Cell Proliferation Research Articles

NUCB-2/Nesfatin-1 promotes the proliferation of nasopharyngeal carcinoma cells.

The association of NUCB-2/Nesfatin-1 with nasopharyngeal carcinoma (NPC) remains unclear. We clarified the role of NUCB-2/Nesfatin-1 in the development, progression and diagnosis of NPC. In nasopharyngeal carcinoma cell lines (5-8F, 6-10B, CNE1, CNE2 and NP69), western blotting, MTT, EdU and other techniques were performed to investigate the role of NUCB-2 in nasopharyngeal carcinoma. 70 tissue samples (39 NPC and 31 rhinitis) and 140 serum samples (including NPC, rhinitis, other head and neck tumors and healthy control) were included to explore the expression of NUCB-2 and its metabolite Nesfatin-1 in tissues or serum of patients with nasopharyngeal carcinoma. NUCB-2 level in NPC tissue was higher than that in rhinitis tissue (P < 0.05). Suppression of NUCB-2 in the NPC cell line CNE2 inhibited proliferation and clone formation of the cells; on the contrary, improvement of NUCB-2 in the NPC cell line CNE1 promoted cell propagation and clone development. An elevated serum level of NUCB-2 in NPC patients was detected, compared to that in patients with other head and neck tumors, rhinitis or healthy donors. Determination of nesfatin-1 combined with EA-IgA, VCA-IgA and Rta-IgG in serum samples for NPC diagnosis reached a sensitivity of 93.6% and a specificity of 94.5%, while the positive and negative predictive value of this diagnostic model was 89.8% and 96.6%, and the accuracy yielded 94.2%. This study revealed that NUCB-2 could enhance proliferation of NPC cells and NUCB-2/nesfatin-1 has the potential to be a serological marker to aid early diagnosis of nasopharyngeal carcinoma.

PinX1-Promoted Autophagy Inhibits Cell Proliferation and Induces Cell Apoptosis by Inhibiting the NF-κB/p65 Signaling Pathway in Nasopharyngeal Carcinoma.

The role of Pin2 telomeric repeat factor 1-interacting telomerase inhibitor 1 (PinX1) in tumorigenesis and development has been extensively studied. As we previously demonstrated, PinX1 plays an important role in modulating epithelial-mesenchymal transition (EMT), stemness, cell proliferation, and apoptosis in nasopharyngeal carcinoma (NPC). However, the relationship between PinX1, autophagy, and cell function in NPC remains unclear. This study aimed to investigate the mechanisms by which PinX1 regulates autophagy in NPC, and to explore its biological role and clinical significance in disease progression. The proliferative capacity of NPC cells was assessed by MTT and xenograft tumorigenicity assays. Autophagic flux was monitored using a tandem monomeric DAPI-FITC-LC3 reporter assay. The rates of apoptosis and the cell cycle in NPC cells were analyzed using flow cytometry. The activation of autophagy and the signaling status of the AKT/mTOR and NF-κB/p65 pathways were evaluated by Western blot analysis. In addition to promoting autophagy and apoptosis, PinX1 overexpression suppressed proliferation, migration, invasion, and decelerated cell-cycle progression in NPC cells. These effects were reversed by inhibiting autophagy with 3-methyladenine. Mechanistic investigations clarified that PinX1 overexpression significantly reduced the expression of p-AKT, p-mTOR, p65, and p-p65. Chloroquine treatment in PinX1-overexpressing cells did not significantly alter p-AKT and p-mTOR levels, whereas 3-MA treatment in PinX1-overexpressing cells resulted in increased p65 and p-p65 expression, relative to untreated PinX1-overexpressing cells. It appears that PinX1 promotes autophagy by inhibiting the AKT/mTOR signaling pathway, which then inhibits NF-κB/p65 pathways, and consequently inhibiting cell proliferation and causing cell apoptosis in NPC cells.

SRSF3/AMOTL1 splicing axis promotes the tumorigenesis of nasopharyngeal carcinoma through regulating the nucleus translocation of YAP1

Dysregulation of serine/arginine splicing factors (SRSFs) and abnormal alternative splicing (AS) have been widely implicated in various cancers but scarcely investigated in nasopharyngeal carcinoma (NPC). Here we examine the expression of 12 classical SRSFs between 87 NPC and 10 control samples, revealing a significant upregulation of SRSF3 and its association with worse prognosis in NPC. Functional assays demonstrate that SRSF3 exerts an oncogenic function in NPC progression. Transcriptome analysis reveals 1,934 SRSF3-regulated AS events in genes related to cell cycle and mRNA metabolism. Among these events, we verify the generation of a long isoform of AMOTL1 (AMOTL1-L) through a direct bond of the SRSF3 RRM domain with the exon 12 of AMOTL1 to promote exon inclusion. Functional studies also reveal that AMOTL1-L promotes the proliferation and migration of NPC cells, while AMOTL1-S does not. Furthermore, overexpression of AMOTL1-L, but not -S, significantly rescues the inhibitory effects of SRSF3 knockdown. Additionally, compared with AMOTL1-S, AMOTL1-L has a localization preference in the intracellular than the cell membrane, leading to a more robust interaction with YAP1 to promote nucleus translocation. Our findings identify SRSF3/AMOTL1 as a novel alternative splicing axis with pivotal roles in NPC development, which could serve as promising prognostic biomarkers and therapeutic targets for NPC.

Hsa_circ_0028007 regulates the progression of nasopharyngeal carcinoma through the miR-1179/SQLE axis.

Nasopharyngeal carcinoma (NPC) is one of the most ordinary malignant tumors. Current research has suggested that circular RNAs play an important role in tumor genesis and progression. The purpose of this study is to explore the function and underlying mechanisms of circ_0028007 in NPC. The levels of circ_0028007, miR-1179, and Squalene epoxidase (SQLE) were detected by quantitative real-time polymerase chain reaction. Cell proliferation was detected by colony formation assay and thymidine analog 5-ethynyl-2'-deoxyuridine assay. Cell apoptosis was detected by flow cytometry. Relevant kits detected caspase-3, glucose, and lactate levels. Western blot assay was used to detect the related protein content. Dual-luciferase reporter assay and RNA pull-down assay were used to examine the target relationship between miR-1179 and circ_0028007 or SQLE. circ_0028007 and SQLE were highly expressed in NPC, while miR-1179 was lowly expressed. circ_0028007 silencing inhibited NPC cell proliferation and promoted apoptosis. However, the effect of circ_0028007 down-regulation on NPC cells was partially restored by co-transfection with miR-1179 inhibitor. Overexpression of SQLE partially restored the cell proliferation inhibited by circ_0028007 knockdown. circ_0028007 could regulate NPC progression via the miR-1179/SQLE axis. Therefore, circ_0028007 might be a new therapeutic target for NPC.

MicroRNA-577/EIF5A2 axis suppressed the proliferation of DDP-resistant nasopharyngeal carcinoma cells by blocking TGF-β signaling pathway.

Diaminodichoroplatinum (DDP) resistance of tumor cells is the culprit of nasopharyngeal carcinoma (NPC) treatment failure. MicroRNA-577 is lowly expressed in NPC tissues, but relevant mechanism is poorly studied. Therefore, this study investigated the role of microRNA-577 in NPC cells with DDP resistance and its mechanism. DDP-resistant NPC cells were established by treatment with DDP at increased concentrations (2, 4, 6, 8, or 10 μg/mL). MicroRNA-577 and EIF5A2 mRNA expressions were detected by qRT-PCR. Cell biological behaviors were assessed via cell function experiments. Expressions of epithelial mesenchymal transformation (EMT)-related proteins were quantified by western blot. The targeting relationship between eukaryotic translation initiation factor 5A2 (EIF5A2) and microRNA-577 was verified through dual-luciferase reporter assay. The tumor volume and weight were measured after subcutaneous tumorigenesis in mice. As observed from the results, microRNA-577 expression was reduced in NPC cells and DDP-resistant NPC cells. Up-regulated microRNA-577 suppressed the malignant behaviors and EMT of DDP-resistant NPC cells, and facilitated cell apoptosis. MicroRNA-577 targeted EIF5A2, and overexpressed EIF5A2 reversed the above effects of up-regulated microRNA-577 on DDP-resistant NPC cells. Besides, EIF5A2 positively regulated TGF-β signaling pathway, and TGF-β treatment offset the promoting effects of EIF5A2 silencing on apoptosis of DDP-resistant NPC cells. Up-regulated microRNA-577 suppressed the proliferation of DDP-resistant NPC cells, and down-regulated the levels of EIF5A2 and TGF-β as well as EMT in vivo. Collectively, microRNA-577/EIF5A2 axis hinders the EMT progression through the blockage of TGF-β signaling pathway, so as to inhibit the proliferation of DDP-resistant NPC.

Epstein–Barr virus microRNA miR-BART2-5p accelerates nasopharyngeal carcinoma metastasis by suppressing RNase Ⅲ endonuclease DICER1

The development and progression of nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) infection. NPC is usually asymptomatic until it spreads to other sites, and more than 70% of cases are classified as locally advanced disease at diagnosis. EBV-positive nasopharyngeal cancer tissues express only limited viral latent proteins, but express high levels of the EBV-encoded BamHI-A rightward transcript (BART) miRNA molecules. Here, we report that EBV-miRNA-BART2-5p (BART2-5p) promotes NPC cell invasion and metastasis invivo and invitro but has no effect on NPC cell proliferation and apoptosis. In addition, BART2-5p altered the mRNA and miRNA expression profiles of NPC cells. The development of human tumors has been reported to be associated with altered miRNAs expression, and overall miRNAs expression is reduced in many types of tumors. We found that BART2-5p downregulated the expression of several miRNAs that could exert oncogenic functions. Mechanistically, BART2-5p directly targets the RNase III endonuclease DICER1, inhibiting its function of cleaving double-stranded stem-loop RNA into short double-stranded RNA, which in turn causes altered expression of a series of key epithelial-mesenchymal transition molecules, and reverting DICER1 expression can rescue this phenotype. Furthermore, analysis from clinical samples showed a negative correlation between BART2-5p and DICER1 expression. According to our study, high expression of BART2-5p in tissues and plasma of patients with NPC is associated with poor prognosis. Our results suggest that, BART2-5p can accelerate NPC metastasis through modulating miRNA profiles which are mediated by DICER1, implying a novel role of EBV miRNAs in the pathogenesis of NPC.

Long non-coding RNA HOTTIP exerts an oncogenic function by regulating HOXA13 in nasopharyngeal carcinoma

BackgroundThe long non-coding RNA HOXA transcript at the distal tip (HOTTIP) and homeobox A13 (HOXA13) have been identified as oncogenes that play a pivotal role in tumorigenesis. However, their specific mechanisms of action in nasopharyngeal carcinoma (NPC) progression remain unclear.Methods and resultsIn the present study, RT-qPCR was employed to quantify RNA expression in NPC cells and tissues. Flow cytometry, MTT, CCK8 and colony formation assays were utilized to assess cell apoptosis and proliferation. Transwell assay was conducted to evaluate migration and invasion while Western blotting was performed for protein expression analysis. Our findings revealed that the expression of HOTTIP was significantly upregulated in NPC cell lines. Inhibition of HOTTIP could induce apoptosis and suppress proliferation, clonogenicity, invasion and metastasis in NPC cells. Knockdown of HOTTIP led to downregulation of HOXA13 expression, which subsequently inhibited the proliferation and metastasis in NPC cells. The inhibitory effects on cell proliferation and metastasis caused by HOTTIP silencing were rescued by HOXA13 overexpression. Additionally, there was a significant positive correlation between HOTTIP and HOXA13, which were found to be elevated in NPC tissues compared to normal tissues.ConclusionsWe have determined that LncRNA HOTTIP facilitates tumorigenesis by modulating the expression of HOXA13 in NPC cells. Targeting HOTTIP/HOXA13 may be a promising therapeutic strategy for NPC.

Mechanism of lncRNA FOXD3-AS1/miR-338-3p in the malignant progression of nasopharyngeal carcinoma through ceRNA.

This work aimed to analyze the impact of lncRNA FOXD3-AS1 (F-A) on the regulation of miR-338-3p (M) on the proliferation (Pro), migration (Mig), and invasion (Inv) of nasopharyngeal carcinoma (NPC) cells. F-A and M levels in human normal nasopharyngeal (NNP) NP69 cells and NPC CNE1 and CNE2 cells were detected by real-time quantitative PCR. After transfection or cotransfection with F-A shRNA, miR-338-3p mimic (MM), and miR-338-3p inhibitor (MI), cell Pro, Mig, and Inv (PMI) were detected using CCK-8, scratch healing, and Transwell chamber experiments, respectively. As a result, relative to NP69 cells, F-A was upregulated in CNE1 and CNE2 cells, while M was downregulated (P<0.01). F-A in CNE1 and CNE2 cells was downregulated and M was upregulated relative to shF-A (P<0.01). Furthermore, shF-A and MM groups demonstrated drastically reduced cell proliferative activity, Mig, and Inv versus CNE1/CNE2 groups. The cell proliferative activity, Mig, and Inv number of the MI group increased substantially (P<0.01). The shF-A+MM group exhibited markedly reduced cell proliferative activity, Mig, and cell number of Inv relative to those of CNE1/CNE2 (P<0.01). Moreover, the shF-A+MI group exhibited greatly increased cell proliferative activity, Mig, and cell number of Inv versus the shF-A+MM group (P<0.01). In short, lncRNA F-A level was abnormally upregulated, and that of M was downregulated in NPC. Interfering with lncRNA F-A level can upregulate M expression. Silencing of lncRNA F-A can inhibit PMI of NPC cells.

High-throughput identification of regulatory elements and functional assays to uncover susceptibility genes for nasopharyngeal carcinoma

Large-scale genetic association studies have identified multiple susceptibility loci for nasopharyngeal carcinoma (NPC), but the underlying biological mechanisms remain to be explored. To gain insights into the genetic etiology of NPC, we conducted a follow-up study encompassing 6,907 cases and 10,472 controls and identified two additional NPC susceptibility loci, 9q22.33 (rs1867277; OR= 0.74, 95% CI= 0.68-0.81, p= 3.08×10-11) and 17q12 (rs226241; OR= 1.42, 95% CI= 1.26-1.60, p= 1.62×10-8). The two additional loci, together with two previously reported genome-wide significant loci, 5p15.33 and 9p21.3, were investigated by high-throughput sequencing for chromatin accessibility, histone modification, and promoter capture Hi-C (PCHi-C) profiling. Using luciferase reporter assays and CRISPR interference (CRISPRi) to validate the functional profiling, we identified PHF2 at locus 9q22.33 as a susceptibility gene. PHF2 encodes a histone demethylase and acts as a tumor suppressor. The risk alleles of the functional SNPs reduced the expression of the target gene PHF2 by inhibiting the enhancer activity of its long-range (4.3 Mb) cis-regulatory element, which promoted proliferation of NPC cells. In addition, we identified CDKN2B-AS1 as a susceptibility gene at locus 9p21.3, and the NPC risk allele of the functional SNP rs2069418 promoted the expression of CDKN2B-AS1 by increasing its enhancer activity. The overexpression of CDKN2B-AS1 facilitated proliferation of NPC cells. In summary, we identified functional SNPs and NPC susceptibility genes, which provides additional explanations for the genetic association signals and helps to uncover the underlying genetic etiology of NPC development.

Exosomal miR-18a-5p promotes EMT and metastasis of NPC cells via targeting BTG3 and activating the Wnt/β-catenin signaling pathway

ABSTRACT This study investigated the underlying mechanism of miR-18a-5p regulating the proliferation, invasion, and metastasis of nasopharyngeal carcinoma (NPC) cells in vitro and in vivo to indicate the pathogenesis of NPC. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was utilized to determine miR-18a-5p expression level in NPC tissues and cell lines. Besides, 2,5-diphenyl-2 H-tetrazolium bromide (MTT) and colony formation assays were employed to detect the effect of miR-18a-5p expression level on NPC cell proliferation. Wound healing and Transwell assays were utilized to detect the effect of miR-18a-5p on NPC cell invasion and migration. The expression levels of epithelial-mesenchymal transition (EMT)-related proteins (Vimentin, N-cadherin, and E-cadherin) were identified by Western blot assay. After collecting exosomes from CNE-2 cells, it was found that exosomal miR-18a-5p secreted from NPC cells promoted NPC cell proliferation, migration, invasion, and EMT, whereas inhibition of miR-18a-5p expression level led to the opposite results. The dual-luciferase reporter assay showed that BTG anti-proliferation factor 3 (BTG3) was the target gene of miR-18a-5p, and BTG3 could overturn the effect of miR-18a-5p on NPC cells. Xenograft mouse model of NPC nude mice showed that miR-18a-5p promoted NPC growth and metastasis in vivo. This study revealed that exosomal miR-18a-5p derived from NPC cells promoted angiogenesis via targeting BTG3 and activating the Wnt/β-catenin signaling pathway.

Elucidating the pharmacological effects of Compound Kushen injection on MYC-P15-CCND1 signaling pathway in nasopharyngeal carcinoma - An in vitro study

Ethnopharmacological relevanceCompound Kushen injection (CKI) is a representative medication of Chinese herbal injection and is often used in the adjuvant treatment of nasopharyngeal carcinoma (NPC), but its antitumor mechanism is poorly understood. Aim of the studyTo preliminarily elucidate the effects and possible mechanisms of CKI on NPC. MethodsIn this work, we explored the possible molecular mechanisms of CKI against NPC by using network pharmacology and molecular docking. In addition, proteomics was used to explore the localization and quantitative information of protein in NPC C666-1 cells after the intervention of CKI, and enrichment analysis was used to obtain the potential targets and pathways. Finally, the effect and the core targets of CKI in the intervention of NPC were explored in vitro experiments. ResultsNetwork pharmacology analysis identified three active components of CKI and 13 key targets. Molecular docking analysis showed that TNF, PTEN, CCND1, MAPK3, IL6, HIF1A, MYC had high affinity with corresponding components. Then the key pathway, cell cycle and the core targets MYC, CCND1, and P15 related to the key pathway were obtained. The results of in vitro experiments showed that CKI could inhibit the proliferation, migration, and invasion of NPC 5–8F cells and C666-1 cells, induce apoptosis of C666-1 cells, and arrest cell cycle G0/G1 phase. In addition, RT-qPCR and western blot showed that the expression of P15 was up-regulated and E2F4, E2F5, c-Myc, CCND1, and P107 was down-regulated in 5–8F cells and C666-1 cells intervened by CKI. ConclusionThe key pathway, cell cycle and the corresponding core targets MYC, CCND1, and P15 were obtained from network pharmacology, molecular docking, and proteomics. CKI could inhibit the proliferation, migration, and invasion of NPC cells, induce apoptosis of C666-1 cells. Especially CKI may arrest cell cycle G0/G1 phase through regulating targets MYC/P15/CCND1 of cell cycle pathway.

The molecular mechanism for inhibiting the growth of nasopharyngeal carcinoma cells using polymethoxyflavonoids purified from pericarp of Citrus reticulata 'Chachi' via HSCCC.

Polymethoxyflavonoids (PMFs), the main bioactive compounds naturally occurring in the pericarp of Citrus reticulata 'Chachi' (CRCP), possess significant antitumor action. However, the action of PMFs in nasopharyngeal carcinoma (NPC) is currently unknown. The present research study was conducted to investigate the inhibitory mechanisms of PMFs from CRCP on NPC growth in vivo and in vitro. In our research, we used high-speed counter-current chromatography (HSCCC) to separate four PMFs (nobiletin (NOB), 3,5,6,7,8,3',4'-heptamethoxyflavone (HMF), tangeretin (TGN), and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (5-HPMF)) from CRCP. CCK-8 assay was used to preliminarily screen cell viability following exposure to the four PMFs. Colony formation, Hoechst-33258 staining, transwell, and wound scratch assays were performed to assess the anti-proliferation, invasion, migration, and apoptosis-inducing effects of HMF on NPC cells. NPC tumors in xenograft tumor transplantation experiments were also established to explore the effect of HMF (100 and 150mg/kg/day) on NPC. The histopathological changes in the treated rats were observed by H&E staining and Ki-67 detection by immunohistochemical techniques. The expressions of P70S6K, p-P70S6K, S6, p-S6, COX-2, p53, and p-p53 were measured by Western blot. The four PMFs were obtained with high purity (>95.0%). The results of the preliminary screening by CCK-8 assay suggested that HMF had the strongest inhibitory effect on NPC cell growth. The results of the colony formation, Hoechst-33258 staining, transwell, and wound scratch assays indicated that HMF had significant anti-proliferation, invasion, migration, and apoptosis-inducing ability in NPC cells. Moreover, HMF suppressed NPC tumor growth in xenograft tumor transplantation experiments. Further investigation suggested that HMF regulated NPC cells proliferation, apoptosis, migration, and invasion by activating AMPK-dependent signaling pathways. In conclusion, HMF-induced AMPK activation inhibited NPC cell growth, invasion, and metastatic potency by downregulating the activation of the mTOR signaling pathway and COX-2 protein levels, as well as enhancing the p53 phosphorylation level. Our study provides a crucial experimental basis for the clinical treatment of NPC, as well as the development and utilization of PMFs from CRCP.

HDAC4 mediated LHPP deacetylation enhances its destabilization and promotes the proliferation and metastasis of nasopharyngeal carcinoma

Studies have shown that acetylation modification plays an important role in tumor proliferation and metastasis. Phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) is downregulated in certain tumors, as a tumor suppressor role. However, the regulation of LHPP expression and its function in nasopharyngeal carcinoma (NPC) remain unclear. In the present study, we found that LHPP was downregulated in NPC, and overexpression of LHPP inhibited the proliferation and invasion of NPC cells. Mechanistically, HDAC4 deacetylated LHPP at K6 and promoted the degradation of LHPP through TRIM21 mediated K48-linked ubiquitination. HDAC4 was confirmed to be highly expressed in NPC cells and promoted the proliferation and invasion of NPC cells through LHPP. Further research found that LHPP could inhibit the phosphorylation of tyrosine kinase TYK2, thereby inhibiting the activity of STAT1. In vivo, knockdown of HDAC4 or treatment with small molecule inhibitor Tasquinimod targeting HDAC4 could significantly inhibit the proliferation and metastasis of NPC by upregulating LHPP. In conclusion, our finding demonstrated that HDAC4/LHPP signal axis promotes the proliferation and metastasis of NPC through upregulating TYK2-STAT1 phosphorylation activation. This research will provide novel evidence and intervention targets for NPC metastasis.

KIF23, under regulation by androgen receptor, contributes to nasopharyngeal carcinoma deterioration by activating the Wnt/β-catenin signaling pathway.

Our study aimed to explore the potential mechanisms of KIF23 regulating function in the progression of nasopharyngeal carcinoma and pinpoint novel therapeutic targets for the clinical treatment of nasopharyngeal carcinoma patients. Firstly, the mRNA and protein level of KIF23 in nasopharyngeal carcinoma was measured using quantitative real-time PCR and western blot. Then, the influence of KIF23 on tumor metastasis and growth in nasopharyngeal carcinoma was determined through the in vivo and in vitro experiments. Lastly, the regulatory mechanisms of KIF23 in nasopharyngeal carcinoma were illustrated in the chromatin immunoprecipitation assay. KIF23 was first found to be overexpressed in nasopharyngeal carcinoma samples, and its expression was associated with poor prognosis. Then, the nasopharyngeal carcinoma cell's proliferation, migration, and invasion potential could be improved by inducing KIF23 expression both in vivo and in vitro. Furthermore, androgen receptor (AR) was found to bind to the KIF23 promoter region directly and enhance KIF23 transcription. At last, KIF23 could accelerate nasopharyngeal carcinoma deterioration via activating the Wnt/β-catenin signaling pathway. AR/KIF23/Wnt/β-catenin pathway promotes nasopharyngeal carcinoma deterioration. Our findings could serve as a new therapeutic strategy for nasopharyngeal carcinoma in the clinical practice.

LINC01376 promotes nasopharyngeal carcinoma tumorigenesis by competitively binding to the SP1/miR-4757/IGF1 axis.

The long non-coding RNA (lncRNA)-microRNA (miRNA) interaction network plays a crucial part in the pathogenesis of nasopharyngeal carcinoma (NPC). Here, we discovered a relationship between LINC01376 and miR-4757 in NPC tumor development. First, LINC01376 was abnormally overexpressed in NPC tissues and cells, and its elevated expression was associated with advanced clinicalstage and shorter distant metastasis-free survival time. Moreover, biological experiments showed that LINC01376 facilitated the proliferative, invasive, and migratory abilities of NPC cells in vitro and in vivo. Mechanistically, bioinformatics and RT-qPCR assays revealed that LINC01376 knockdown upregulated the expression level of downstream miR-4757, including miR-4757 primary transcript (pri-miR-4757) and mature miR-4757. Furthermore, LINC01376 competitively sponged the transcription factor SP1 and reduced its enrichment in the upstream promoter region of miR-4757 to repress miR-4757 expression. Finally, insulin-like growth factor 1(IGF1) was identified as the target of miR-4757. Rescue experiments indicated that LINC01376 accelerated NPC cell proliferation, migration, and invasion through the miR-4757-5p/IGF1 axis. In conclusion, the SP1/miR-4757/IGF1 axis, which is regulated by LINC01376 in NPC deterioration and metastasis, is expected to provide new insights into the molecular mechanism of NPC carcinogenesis.

Retraction: Interaction between miR-572 and PPP2R2C, and their effects on the proliferation, migration, and invasion of nasopharyngeal carcinoma (NPC) cells.

Retraction: Interaction between miR-572 and PPP2R2C, and their effects on the proliferation, migration, and invasion of nasopharyngeal carcinoma (NPC) cells.

Hypoxia-induced degradation of PICK1 by RBCK1 promotes the proliferation of nasopharyngeal carcinoma cells

AimsHypoxia is an important feature of nasopharyngeal carcinoma (NPC). “Protein interacting with PRKCA 1” (PICK1) is commonly downregulated in human malignancies and is functionally related to poor prognosis. However, there is a limited understanding of the upstream mechanisms regulating PICK1 currently. Main methodsPICK1 and HIF-1α expression levels were analyzed by Immunohistochemistry (IHC), western blotting, and quantitative real-time PCR assay. Protein stability and ubiquitin assays were used to investigate PICK1 protein degradation. Immunofluorescence and co-immunoprecipitation assays were used to demonstrate the interaction between RBCK1 and PICK1. Gene knockdown by siRNA transfection was used to investigate the role of HIF-1α and RBCK1 in hypoxia-induced PICK1 degradation. Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2′-deoxyuridine (EdU) assays and subcutaneous xenograft nude models were used to explore the roles of RBCK1 and PICK1 in NPC cell proliferation. Key findingsPICK1 expression in NPC tissue was negatively relative to that of HIF-1α. HIF-1α downregulated PICK1 expression by facilitating its ubiquitination by the E3 ligases RANBP2-type and C3HC4-type zinc finger containing 1 (RBCK1), thereby enhancing proteasome-mediated PICK1 degradation. RBCK1 knockdown inhibited NPC cell proliferation, which was ameliorated by double knockdown of RBCK1/PICK1. SignificanceThese data provide evidence for an NPC cell adaptation mechanism to hypoxia, where HIF-1α regulates RBCK1, which targets PICK1 for degradation to promote cell proliferation.

Aloe-emodin targets multiple signaling pathways by blocking ubiquitin-mediated degradation of DUSP1 in nasopharyngeal carcinoma cells.

Aloe-emodin (AE) has been shown to inhibit the proliferation of several cancer cell lines, including human nasopharyngeal carcinoma (NPC) cell lines. In this study, we confirmed that AE inhibited malignant biological behaviors, including cell viability, abnormal proliferation, apoptosis, and migration of NPC cells. Western blotting analysis revealed that AE upregulated the expression of DUSP1, an endogenous inhibitor of multiple cancer-associated signaling pathways, resulting in blockage of the extracellular signal-regulated kinase (ERK)-1/2, protein kinase B (AKT), and p38-mitogen activated protein kinase（p38-MAPK） signaling pathways in NPC cell lines. Moreover, the selective inhibitor of DUSP1, BCI-hydrochloride, partially reversed the AE-induced cytotoxicity and blocked the aforementioned signaling pathways in NPC cells. In addition, the binding between AE and DUSP1 was predicted via molecular docking analysis using AutoDock-Vina software and further verified via a microscale thermophoresis assay. The binding amino acid residues were adjacent to the predicted ubiquitination site (Lys192) of DUSP1. Immunoprecipitation with the ubiquitin antibody, ubiquitinated DUSP1 was shown to be upregulated by AE. Our findings revealed that AE can stabilize DUSP1 by blocking its ubiquitin-proteasome-mediated degradation and proposed an underlying mechanism by which AE-upregulated DUSP1 may potentially target multiple pathways in NPC cells.

Long noncoding RNA long intergenic non-protein-coding RNA 173 contributes to nasopharyngeal carcinoma progression by regulating microRNA-765/Gremlin 1 pathway.

Long intergenic non-protein-coding RNA 173 (LINC00173) executes vital functions in various cancers. Nevertheless, its role and expression in nasopharyngeal carcinoma (NPC) have yet to be investigated. Here, we investigated its effects on the malignancy characteristics of NPC and elucidated the potential molecular mechanism of LINC00173 in NPC progression. Quantitative real-time reverse transcription-PCR (qRT-PCR) and immunoblotting were conducted to estimate the LINC00173, microRNA-765 (miR-765), and Gremlin 1 (GREM1) expressions in NPC cells and tissues. Cell counting kit-8 (CCK8), colony formation, and wound healing experiments were done to evaluate the proliferation, growth, and migration of NPC cells, respectively. The tumorous growth of NPC cells in vivo was assessed through the xenograft tumor experiment. Furthermore, the interactions among miR-765, LINC00173, and GREM1 were investigated through bioinformatics analyses, luciferase reporter and RNA immunoprecipitation chip assays. An upregulated LINC00173 expression was found in NPC cell lines and tissues. The functional experiments uncovered that its downregulation repressed NPC cell proliferation, growth, and migration. In addition, LINC00173 knockdown hampered the NPC cells' tumorous growth in vivo. These effects could partially be reversed by downregulating miR-765. GREM1 is a downstream target of miR-765. GREM1 knockdown could repress the proliferation, growth, and migration of NPC cells. Nonetheless, these anti-tumor effects could be abolished by miR-765 downregulation. Mechanistically, LINC00173 increased the expression of GREM1 by binding with miR-765. LINC00173 functions as an oncogenic factor by binding with miR-765 to promote the progression of NPC via GREM1 upregulation. This study provides a novel insight into the molecular mechanisms involved in NPC progression.

MiR-137 Regulates Proliferation, Migration, Invasion and EMT of Nasopharyngeal Carcinoma Cells by Targeting TWIST1

To investigate the effects of miR-137 on biological cell function of nasopharyngeal carcinoma (NPC) cells. Totally, 31 pairs of NPC tissues and para-cancer tissues were collected. Meanwhile, human immortalized nasopharyngeal epithelial cell lines (NP69) and human NPC cell lines (6-10B) were cultured. The abilities of cell proliferation, invasion and migration were detected by CCK-8 and Transwell assay, respectively. The relative protein and mRNA expression level was detected by Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. In quantitative real-time polymerase chain reaction (qRT-PCR) experiment, miR-137 was found widely low-expressed in clinical samples and cell lines of nasopharyngeal carcinoma (NPC). On-line target gene prediction software was applied to screen potential downstream target of miR-137 in NPC. Then, Twist Family BHLH Transcription Factor 1 (TWIST1) was verified by luciferase reporter assay and Western blot experiments as a target for negative regulation of miR-137 in NPC cells. We up-regulated the expression of miR-137 and/or TWIST1 in 6-10Bin vitro, and then examined the effects of cell function after by CCK8, Transwell, scratch-wound and Western blot experiments. The results showed that decreased expression of TWIST1 resulting from up-regulation of miR-137 in 6-10B cells could inhibit the biological functions of cells including proliferation, invasion, migration and process of epithelial-mesenchymal transition (EMT). Our research discovered the suppressor function of miR-137 on NPC cells by targeting TWIST1, suggesting that miR-137 could be used as a potential therapeutic target for NPC.