Association of E-cadherin methylation with risk of nasopharyngeal cancer: A meta-analysis

Upregulation of E-cadherin by the combination of methionine restriction and HDAC2 intervention for inhibiting gastric carcinoma metastasis

Invasion and metastasis are the leading causes of death in individuals with malignant tumors, including gastric cancer. In this study, we aim to explore the effect and related mechanisms of methionine restriction (MR) on gastric carcinoma metastasis. In the MR cell model, gastric carcinoma cells are cultured in the MR medium, and in the animal model, BALB/c nude rodents are administered with a methionine-free diet after receiving injections of MKN45 cells into the caudal vein. Transwell assay is used to detect cell invasion and migration. Chromatin immunoprecipitation is performed to investigate the levels of H3K9me2, H3K27Ac, and H3K27me3 in the E-cadherin promoter. The results show that MR inhibits gastric carcinoma cell migration, invasion, and lung metastasis. MR increases E-cadherin while reducing the H3K27me3 level in the E-cadherin promoter. E-cadherin expression in gastric carcinoma cells is adversely regulated by HDAC2. Overexpressing HDAC2 reduces the H3K27Ac level in the E-cadherin promoter, while interfering with HDAC2 increases the H3K27Ac level. HDAC2 interference under MR conditions further upregulates E-cadherin expression and inhibits gastric carcinoma cell migration, invasion, and lung metastasis. MR combined with HDAC2 interference promotes E-cadherin expression by mediating the methylation and acetylation of E-cadherin, thus inhibiting the invasion, migration, and lung metastasis of gastric carcinoma cells. Our study provides a new theoretical basis for the inhibitory effect of MR on gastric cancer.

Hsa_circ_0013561 promotes progression of nasopharyngeal carcinoma by activating JAK2/STAT3 signaling pathway

OBJECTIVE

Nasopharyngeal Carcinoma (NPC) is a malignancy of epithelium of epithelium of the nasopharynx, with the highest incidence of otolaryngeal malignancies. A growing number of studies confirm that Circular RNA (circRNA) plays an important role in tumor development, including Hsa_circ_0013561. This study aims to elucidate the process and mechanism of NPC regulation hsa_circ_0013561.

METHODS

In this study, circRNA expression nodes and subcellular localization in NPC tissues were analyzed by fluorescence in situ hybridization. The expression of hsa_circ_0013561 in NPC cells was further clarified by RT-qPCR. At the same time, the lentivirus vector interfered by hsa_circ_0013561 was constructed and transfected. The cell proliferation was detected by CCK-8 method, EdU assay and plate cloning assay. The cell cycle and apoptosis were detected by flow cytometry, and the cell migration ability was detected by wound healing assay and Transwell assay. Western blotting examined the expression of apoptosis, Epithelial-Mesenchymal Transition (EMT)-associated proteins, and Janus Kinase/Signal Transductor and Activator of Transcription (JAK/STAT) signaling pathway-related proteins.

RESULTS

The results showed that the expression of hsa_circ_0013561 in NPC samples was significantly upregulated and hsa_circ_0013561 localized in the cytoplasm. After down-regulating hsa_circ_0013561 expression, it significantly inhibited the proliferation and metastasis ability of NPC, inhibited EMT progression, and promoted apoptosis. Further studies showed that interference hsa_circ_0013561 significantly inhibited JAK2/STAT3 signaling pathway activation and induced the expression of apoptosis-related proteins.

CONCLUSION

In summary, we found that hsa_circ_0013561 is a pro-tumor circRNA in NPC, which can reduce the activation of JAK2/STAT3 pathway by knocking down hsa_circ_0013561, thereby slowing down the malignant progression of NPC. OXFORD CENTRE FOR EVIDENCE-BASED MEDICINE 2011 LEVELS OF EVIDENCE: Level 4.

Epithelial-to-Mesenchymal Transition in Metastasis: Focus on Laryngeal Carcinoma

In epithelial neoplasms, such as laryngeal carcinoma, the survival indexes deteriorate abruptly when the tumor becomes metastatic. A molecular phenomenon that normally appears during embryogenesis, epithelial-to-mesenchymal transition (EMT), is reactivated at the initial stage of metastasis when tumor cells invade the adjacent stroma. The hallmarks of this phenomenon are the abolishment of the epithelial and acquisition of mesenchymal traits by tumor cells which enhance their migratory capacity. EMT signaling is mediated by complex molecular pathways that regulate the expression of crucial molecules contributing to the tumor’s metastatic potential. Effectors of EMT include loss of adhesion, cytoskeleton remodeling, evasion of apoptosis and immune surveillance, upregulation of metalloproteinases, neovascularization, acquisition of stem-cell properties, and the activation of tumor stroma. However, the current approach to EMT involves a holistic model that incorporates the acquisition of potentials beyond mesenchymal transition. As EMT is inevitably associated with a reverse mesenchymal-to-epithelial transition (MET), a model of partial EMT is currently accepted, signifying the cell plasticity associated with invasion and metastasis. In this review, we identify the cumulative evidence which suggests that various aspects of EMT theory apply to laryngeal carcinoma, a tumor of significant morbidity and mortality, introducing novel molecular targets with prognostic and therapeutic potential.

Identification of a novel microRNA profile including miR-106b, miR-17, miR-20b, miR-18a and miR-93 in the metastasis of nasopharyngeal carcinoma

BACKGROUND

Metastasis often leads to poor prognosis in nasopharyngeal carcinoma (NPC) patients. Evidence has indicated the important roles of microRNA (miRNA) in cancer metastasis. The aim of this study was to identify and verify the key miRNAs that might be involved in the development of NPC metastasis.

METHODS

Microarray data were obtained and analyzed to screen the differentially expressed miRNAs (DEMs) between NPC tissues with metastasis and those without metastasis. The target genes of the DEMs were predicted and their functions were annotated. Then, candidate hub genes were screened out through protein-protein interaction analysis, and the key miRNAs were identified. Afterwards, the expression levels of the key miRNAs were assessed by qRT-PCR based on an in vitro model.

RESULTS

A total of 22 DEMs were screened out, and 616 target genes were predicted. Gene Ontology (GO) and pathway enrichment analysis showed that the target genes may be enriched in a diversity of GO terms and signaling pathways. Among them, eleven hub genes were identified, such as PTEN, KAT2B, CCND1, STAT3, and MAP3K5. Moreover, a five-miRNA profile (miR-106b, miR-17, miR-20b, miR-18a and miR-93) was identified and their expression levels were tested to be up-regulated in high-metastatic NPC cells relative to low-metastatic ones.

CONCLUSION

The present study revealed that five miRNAs (miR-106b, miR-17, miR-20b, miR-18a and miR-93) and several hub genes such as PTEN, KAT2B, CCND1, STAT3, and MAP3K5, might play critical roles in the development of NPC metastasis. Future investigations are needed to confirm the results.

Aberrant hypermethylation-mediated downregulation of antisense lncRNA ZNF667-AS1 and its sense gene ZNF667 correlate with progression and prognosis of esophageal squamous cell carcinoma

Natural antisense lncRNAs can interfere with their corresponding sense transcript to elicit concordant or discordant regulation. LncRNA ZNF667-AS1 and its sense gene ZNF667 were found to be downregulated in esophageal squamous cell carcinoma (ESCC) tissues by RNA sequencing; however, the exact roles of both genes in ESCC occurrence and development have not been clarified. This study was to investigate the expression patterns, epigenetic inactivation mechanisms, function, and prognostic significance of ZNF667-AS1 and ZNF667 in ESCC tumorigenesis. Frequent downregulation of ZNF667-AS1 and ZNF667 was detected in esophageal cancer cells and ESCC tissues. The expression levels of ZNF667-AS1 and ZNF667 were significantly reversed by treatment with 5-Aza-dC and TSA in esophageal cancer cell lines. The CpG sites hypermethylation within proximal promoter influenced the binding ability of transcription factor E2F1 to the binding sites and then affected the transcription and expression of ZNF667-AS1 and ZNF667. Overexpression of ZNF667-AS1 and ZNF667 suppressed the viability, migration, and invasion of esophageal cancer cells in vitro. Overexpression of ZNF667-AS1 increased mRNA and protein expression level of ZNF667. ZNF667-AS1 interacts with and recruits TET1 to its target gene ZNF667 and E-cadherin to hydrolyze 5′-mc to 5′-hmc and further activates their expression, meanwhile, ZNF667-AS1 also interacts with UTX to decrease histone H3K27 tri-methylation to activate ZNF667 and E-cadherin expression. Furthermore, ZNF667-AS1 or ZNF667 expression and promoter methylation status were correlated with ESCC patients’ survival. Thus, these findings suggest that ZNF667-AS1 and ZNF667 may act as tumor suppressors and may serve as potential targets for antitumor therapy.

F factor plasmid-mediated Epstein-Barr virus genome introduction establishes an EBV positive NPC cell model

Background

Most Epstein-Barr virus (EBV)-positive cells lose the EBV episomes upon prolonged propagation.

Purpose

The purposes of this study were to establish a simple cell model for nasopharyngeal carcinoma (NPC) research by introducing a plasmid with the EBV genome into NPC cells and then to investigate the resulting changes in malignant biological behaviour and NPC-associated signalling pathways.

Methods

HONE1 NPC cells were transfected with F-factor plasmids including the EBV genome (HONE1-EBV cells). Then cell proliferation, migration, cell cycle distribution and apoptosis were evaluated in vitro by using CCK8, transwell and flow cytometry assays respectively. EBV-encoded proteins and cell signal tranducting proteins were detected by western blot assays. EBV-encoded RNAs were detected by in situ hybridization. EBV particles were assayed by transmission electron microscope (TEM). The morphology of cells were detected by immunofluorescence assays for alpha-tubulin.

Results

Latent membrane protein 1 (LMP1), latent membrane protein 2A (LMP2A), Epstein-Barr nuclear antigen 1 (EBNA1) and EBV-encoded small RNAs (EBERs) were successfully expressed in HONE1-EBV cells. No EBV particles were founded by TEM. Introduction of the EBV genome significantly promoted proliferation, cell cycle progression and migration and inhibited apoptosis in HONE1 cells. Immunofluorescence assays showed that the morphology of HONE1-EBV cells changed into spindle. Furthermore, EBV genome introduction significantly inhibited the JAK/STAT signalling pathway, while it activated the PI3K-AKT and NF-κB signalling pathways in HONE1 cells.

Conclusion

These findings suggest that F-factor plasmid-mediated EBV genome introduction was successful in constructing an EBV positive cell model, which showed deteriorated biological behavior and activated NPC-associated signalling pathways. This model can serve as a good tool for studying EBV in NPC, but the subtle differences in cancer-associated pathways must be considered.