RESUMO
Epstein-Barr virus (EBV) is a tumorigenic virus that can cause various human malignancies such as nasopharyngeal carcinoma (NPC) and gastric cancer (GC). EBV encodes 44 mature micro (mi)RNAs, mostly exhibiting oncogenic properties and promoting cancer progression. However, we have previously found that one EBV-encoded miRNA, namely EBV-miR-BART6-3p, acts as a tumor suppressor by inhibiting metastasis and invasion. Here, we report that EBV-miR-BART6-3p inhibits the proliferation of EBV-associated cancers, NPC, and GC, by targeting and downregulating a long non-coding RNA (lncRNA), LOC553103. Through proteomics analysis, we determined that stathmin (STMN1) is affected by EBV-miR-BART6-3p and LOC553103. Further, via RNA immunoprecipitation and luciferase reporter assay, we confirmed that LOC553103 directly binds and stabilizes the 3'UTR region of STMN1 mRNA. These results indicate that the EBV-miR-BART6-3p/LOC553103/STMN1 axis regulates the expression of cell cycle-associated proteins, which then inhibit EBV-associated tumor cell proliferation. These findings provide potential targets or strategies for novel EBV-related cancer treatments, as well as contributes new insights into the understanding of EBV infection-related carcinogenesis.
Assuntos
Proliferação de Células/genética , Infecções por Vírus Epstein-Barr/genética , Herpesvirus Humano 4/genética , MicroRNAs/genética , RNA Longo não Codificante/genética , Estatmina/genética , Regiões 3' não Traduzidas/genética , Animais , Carcinogênese/genética , Linhagem Celular , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Carcinoma Nasofaríngeo/genética , Neoplasias Nasofaríngeas/genética , RNA Viral/genética , Neoplasias Gástricas/genéticaRESUMO
OBJECTIVE: To discuss the effects of Epstein-Barr virus (EBV)-encoded BamHI A rightward transcript (BART) microRNA (miR-BART6-5p) by targeting Dicer1 on biological properties and radiosensitivity of nasopharyngeal carcinoma (NPC). METHODS: NPC patients (n = 96) treated with radiotherapy were collected from Jan 2010 to Jan 2011. Real-time quantitative PCR (qRT-PCR) and western blot were carried out to measure the expression of miR-BART6-5p and Dicer1. Dual luciferase reporter gene assay verified that miR-BART6-5p targeted Dicer1. CCK8, wound-healing, Transwell and Annexin-FITC/PI were employed to evaluate the effects of Dicer1 mediated by miR-BART6-5p on biological characteristics of NPC cells. The radiosensitivity of miR-BART6-5p targeting Dicer1 was assessed in vitro and in vivo. RESULTS: Increased miR-BART6-5p and decreased Dicer1 were discovered in NPC patients, displaying a close association with T-stage, clinical stage, as well as Pre-DNA of NPC. While elevated Dicer1 and miR-BART6-5p down-regulation in NPC patients were found after effective radiotherapy. Both miR-BART6-5p and Dicer1 were prognostic factors of NPC. Down-regulation of miR-BART6-5p could enhance Dicer1 expression and inhibit NPC cell proliferation, invasion and migration with promoted apoptosis. Clone formation assay also showed miR-BART6-5p down-regulation reduced planting efficiency (PE), which further decreased with the increased dose of irradiation. Injection with miR-BART6-5p inhibitors in nude mice after 6-Gy irradiation contributed to the overexpression of Dicer1 and the inhibition of tumor growth. CONCLUSIONS: EBV-miR-BART6-5p may target Dicer1 to facilitate proliferation and metastasis of NPC cells and suppress apoptosis, thus being a new target for NPC therapy.
Assuntos
Linhagem Celular Tumoral/efeitos da radiação , RNA Helicases DEAD-box/genética , Carcinoma Nasofaríngeo/genética , Carcinoma Nasofaríngeo/radioterapia , Neoplasias Nasofaríngeas/genética , Neoplasias Nasofaríngeas/radioterapia , Tolerância a Radiação/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , China , Feminino , Regulação Neoplásica da Expressão Gênica , Herpesvirus Humano 4/genética , Humanos , Masculino , Camundongos , Camundongos Nus , MicroRNAs/genética , Pessoa de Meia-Idade , Carcinoma Nasofaríngeo/fisiopatologia , Neoplasias Nasofaríngeas/fisiopatologiaRESUMO
Recognition of viral pathogen-associated molecular patterns by pattern recognition receptors (PRRs) is the first step in the initiation of a host innate immune response. As a PRR, RIG-I detects either viral RNA or replication transcripts. Avoiding RIG-I recognition is a strategy employed by viruses for immune evasion. Epstein-Barr virus (EBV) infects the majority of the human population worldwide. During the latent infection period there are only a few EBV proteins expressed, whereas EBV-encoded microRNAs, such as BART microRNAs, are highly expressed. BART microRNAs regulate both EBV and the host's gene expression, modulating virus proliferation and the immune response. Here, through gene expression profiling, we found that EBV miR-BART6-3ps inhibited genes of RIG-I-like receptor signaling and the type I interferon (IFN) response. We demonstrated that miR-BART6-3p rather than other BARTs specifically suppressed RIG-I-like receptor signaling-mediated IFN-ß production. RNA-seq was used to analyze the global transcriptome change upon EBV infection and miR-BART6-3p mimics transfection, which revealed that EBV infection-triggered immune response signaling can be repressed by miR-BART6-3p overexpression. Furthermore, miR-BART6-3p inhibited the EBV-triggered IFN-ß response and facilitated EBV infection through targeting the 3'UTR of RIG-I mRNA. These findings provide new insights into the mechanism underlying the strategies employed by EBV to evade immune surveillance.
Assuntos
Infecções por Vírus Epstein-Barr/imunologia , Herpesvirus Humano 4/genética , Túbulos Renais Proximais/virologia , MicroRNAs/genética , RNA Viral/genética , Linhagem Celular , Interações Hospedeiro-Patógeno , Humanos , Evasão da Resposta Imune , Imunidade Inata , Túbulos Renais Proximais/imunologia , Moléculas com Motivos Associados a Patógenos/imunologia , Receptores de Reconhecimento de Padrão/metabolismo , Receptores do Ácido Retinoico/metabolismo , Transdução de SinaisRESUMO
Burkitt lymphoma (BL) is an aggressive neoplasm characterized by consistent morphology and phenotype, typical clinical behavior and distinctive molecular profile. The latter is mostly driven by the MYC over-expression associated with the characteristic translocation (8;14) (q24; q32) or with variant lesions. Additional genetic events can contribute to Burkitt Lymphoma pathobiology and retain clinical significance. A pathogenetic role for Epstein-Barr virus infection in Burkitt lymphomagenesis has been suggested; however, the exact function of the virus is largely unknown.In this study, we investigated the molecular profiles (genes and microRNAs) of Epstein-Barr virus-positive and -negative BL, to identify specific patterns relying on the differential expression and role of Epstein-Barr virus-encoded microRNAs.First, we found significant differences in the expression of viral microRNAs and in selected target genes. Among others, we identified LIN28B, CGNL1, GCET2, MRAS, PLCD4, SEL1L, SXX1, and the tyrosine kinases encoding STK10/STK33, all provided with potential pathogenetic significance. GCET2, also validated by immunohistochemistry, appeared to be a useful marker for distinguishing EBV-positive and EBV-negative cases. Further, we provided solid evidences that the EBV-encoded microRNAs (e.g. BART6) significantly mold the transcriptional landscape of Burkitt Lymphoma clones.In conclusion, our data indicated significant differences in the transcriptional profiles of EBV-positive and EBV-negative BL and highlight the role of virus encoded miRNA.