Promoted Nasopharyngeal Carcinoma Cell Invasion Research Articles

METTL3-stabilized super enhancers-lncRNA SUCLG2-AS1 mediates the formation of a long-range chromatin loop between enhancers and promoters of SOX2 in metastasis and radiosensitivity of nasopharyngeal carcinoma.

Super enhancers (SE) play pivotal roles in cell identity and diseases occur including tumorigenesis. The depletion of SE-associated lncRNA transcripts, also known as super-lncRNA, causes the activity of SE to be dysregulated. We screened and identified an elevated metastasis-associated SE-lncRNA SUCLG2-AS1 in nasopharyngeal carcinoma (NPC) using RNA-sequencing, real-time quantitative polymerase chain reaction (RT-qPCR) and bioinformatics. Western blotting, RT-qPCR, methylated RNA immunoprecipitation (MeRIP), RNA immunoprecipitation, chromatin immunoprecipitation, RNA pull-down and 3C (chromosome conformation capture assays) were used for mechanistic studies. SUCLG2-AS1 was correlated with a poor prognosis. SUCLG2-AS1 promotes NPC cell invasion and metastasis while repressing apoptosis and radiosensitivity in vitro and in vivo. Mechanistically, high SUCLG2-AS1 expression occurred in an m6A-dependent manner. SUCLG2-AS1 was found to be located in the SE region of SOX2, and it regulated the expression of SOX2 via long-range chromatin loop formation, which via mediating CTCF (transcription factor) occupied the SE and promoter region of SOX2, thus regulating the metastasis and radiosensitivity of NPC. Taken together, our data suggest that SUCLG2-AS1 may serve as a novel intervention target for the clinical treatment of 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.

Curcumol inhibits EBV-positive Nasopharyngeal carcinoma migration and invasion by targeting nucleolin

Metastasis is a major cause of recurrence and death in patients with EBV-positive Nasopharyngeal carcinoma (NPC). Previous reports documented that curcumol has both anti-cancer and anti-viral effects, but there is little literature systematically addressing the mechanism of curcumol in EBV-positive tumors. Previously we found that nucelolin (NCL) is a target protein of curcumol in CNE2 cells, an EBV-negative NPC, and in this experiment, we reported a critical role for NCL in promoting migration and invasion of C666-1 cells, an EBV-positive NPC, and found that the expression of NCL determined the level of curcumol's efficacy. Mechanistically, NCL interacted with Epstein-Barr Virus Nuclear Antigen 1 (EBNA1) to activate VEGFA/VEGFR1/PI3K/AKT signaling pathway, which in turn promoted NPC cell invasion and metastasis. Moreover, further study showed that the differential expression of NCL and curcumol intervention only had a regulatory effect on the nuclear accumulation of VEGFR1, which strengthened the anti-cancer effect of curcumol mediated through NCL. Our findings indicated that curcumol exerted anti EBV-positive NPC invasion and metastasis by downregulating EBNA1 and inhibiting VEGFA/VEGFR1/PI3K/AKT signaling by targeting NCL, which provides a novel pharmacological basis for curcumol's clinical use in treating patients with EBV-positive NPC

VEGF promotes migration and invasion by regulating EMT and MMPs in nasopharyngeal carcinoma.

Background: Vascular endothelial growth factor (VEGF) is an important pro-angiogenic factor. Accumulating data have indicated that VEGF is involved in tumour metastasis. However, the mechanism through which VEGF regulates nasopharyngeal carcinoma (NPC) metastasis is largely unknown. This study aimed to examine the biological function of VEGF in NPC metastasis and its underlying mechanism.Methods: We used western blotting and qPCR to examine the difference in VEGF expression between NPC cells and the immortalized nasopharyngeal epithelial cell line NP69. Wound healing assays, transwell assays and animal experiments were used to further verify the role of VEGF in the invasion and migration of NPC cells. The protein levels of the epithelial-mesenchymal transition (EMT) and matrix metalloproteinase (MMP) family were analysed by immunofluorescence (IF) and western blotting. Enzyme-linked immunosorbent assay (ELISA) and transwell assays were used to determine whether VEGF enhanced the invasion and migration of NPC cells in an autocrine manner. Western blotting was used to examine how autocrine VEGF-VEGFR2 signalling regulated EMT and MMPs.Results: We observed higher levels of VEGF in NPC cells than that in NP69 cells and identified an association between high VEGF levels and tumour invasion and migration. Mechanistically, the VEGF-mediated increase in EMT markers, MMP2 and MMP9 promoted NPC cell invasion and migration. Additionally, NPC cells secreted VEGF to promote cell invasion, migration and angiogenesis. Autocrine VEGF-VEGFR2 signalling increased ERK1/2 phosphorylation, promoted EMT process and MMPs at the indicated times.Conclusion: This study revealed that VEGF plays a role in controlling NPC cell metastasis by regulating EMT markers and MMPs in an autocrine manner.

MicroRNA-432 Suppresses Invasion and Migration via E2F3 in Nasopharyngeal Carcinoma.

BackgroundE2F transcription factor 3 (E2F3) is oncogenic and dysregulated in various malignancies. Complex networks involving microRNAs (miRNAs) and E2F3 regulate tumorigenesis and progression. However, the potential roles of E2F3 and its target miRNAs in nasopharyngeal carcinoma (NPC) are rarely reported.MethodsE2F3 expression was detected in human NPC tissues and cell lines through quantitative real-time PCR. NPC cell proliferation, migration, and invasion were evaluated in vitro by colony forming, cell counting kit-8, wound healing, and Transwell invasion assays. Publicly available database software was used to explore the target miRNAs of E2F3. Dual-luciferase reporter assay was performed to identify the direct relationship. The function of miRNAs in vivo was investigated by using a tumor xenograft model.ResultsE2F3 was upregulated in NPC cell lines and tissues, and its exotic expression promoted NPC cell invasion and migration. E2F3 was identified as a target of miR-432, which restrained NPC cell invasion and migration in vitro and in vivo. Further experiments revealed that miR-432 repressed the invasion and migration potential of NPC cells by modulating E2F3 expression.ConclusionmiRNA-432 suppressed the malignant biological behavior of NPC cells by targeting E2F3. This study provided further insights into NPC prognosis and treatment.

Long non-coding RNA DANCR stabilizes HIF-1α and promotes metastasis by interacting with NF90/NF45 complex in nasopharyngeal carcinoma.

Long noncoding RNAs (lncRNAs) play an important role in the development and progression of cancers. However, the clinical significances of lncRNAs and their functions and mechanisms in nasopharyngeal carcinoma (NPC) remain largely unclear.Methods: Quantitative RT-PCR was used to determine DANCR expression and Kaplan-Meier curves were used to evaluate its prognostic value. RNA sequencing followed by bioinformatic analysis was performed to determine the potential function of DANCR. In vitro and in vivo experiments were conducted to investigate its biological effects. DANCR-interacting proteins were identified by RNA pull-down assay followed by mass spectrometry and western blotting, and then confirmed by RNA immunoprecipitation (RIP) assays.Results: Our previous microarray analysis identified a metastasis-associated lncRNA DANCR. Here, we found that DANCR was upregulated in NPC, especially in those with lymph lode metastasis, and its upregulation could predict poor survival. We then constructed a prognostic predictive model. RNA sequencing followed by bioinformatic analysis revealed that DANCR was responsible for NPC metastasis and hypoxia phenotype. Functional studies showed that DANCR promoted NPC cell invasion and metastasis in vitro and in vivo. Further investigation suggested that DANCR could increase HIF-1α mRNA stability through interacting with the NF90/NF45 complex. Additionally, overexpression of HIF-1α in DANCR knockdown cells restored its suppressive effects on NPC cell migration and invasion.Conclusions: Taken together, our results suggest that DANCR acts as a prognostic biomarker and increases HIF-1α mRNA stability by interacting with NF90/NF45, leading to metastasis and disease progression of NPC.