NR2F1-AS1/miR-190a/PHLDB2 Induces the Epithelial-Mesenchymal Transformation Process in Gastric Cancer by Promoting Phosphorylation of AKT3

Emerging Roles and Mechanisms of RNA Modifications in Neurodegenerative Diseases and Glioma

Despite a long history of research, neurodegenerative diseases and malignant brain tumor gliomas are both considered incurable, facing challenges in the development of treatments. Recent evidence suggests that RNA modifications, previously considered as static components of intracellular RNAs, are in fact dynamically regulated across various RNA species in cells and play a critical role in major biological processes in the nervous system. Innovations in next-generation sequencing have enabled the accurate detection of modifications on bases and sugars within various RNA molecules. These RNA modifications influence the stability and transportation of RNA, and crucially affect its translation. This review delves into existing knowledge on RNA modifications to offer a comprehensive inventory of these modifications across different RNA species. The detailed regulatory functions and roles of RNA modifications within the nervous system are discussed with a focus on neurodegenerative diseases and gliomas. This article presents a comprehensive overview of the fundamental mechanisms and emerging roles of RNA modifications in these diseases, which can facilitate the creation of innovative diagnostics and therapeutics for these conditions.

Depletion of PHLDB2 Suppresses Epithelial-Mesenchymal Transition and Enhances Anti-Tumor Immunity in Head and Neck Squamous Cell Carcinoma

The role of Pleckstrin homology-like domain family B member 2 (PHLDB2) in the regulation of cell migration has been extensively studied. However, the exploration of PHLDB2 in head and neck squamous cell carcinoma (HNSCC) is still limited in terms of expression, function, and therapeutic potential. In this study, we discovered an upregulation of PHLDB2 expression in HNSCC tissues which was correlated with a negative prognosis in patients with HNSCC. Additionally, we determined that a high level of expression of PHLDB2 is crucial for maintaining cell migration through the regulation of the epithelial-mesenchymal transition (EMT). Furthermore, we demonstrated that the ablation of PHLDB2 in tumor cells inhibited tumorigenicity in a C3H syngeneic tumor-bearing mouse model. Mechanistically, PHLDB2 was found to be involved in the regulation of T cell anti-tumor immunity, primarily by enhancing the activation and infiltration of CD8+ T cells. In light of these findings, PHLDB2 emerges as a promising biomarker and therapeutic target for interventions in HNSCC.

The role of m6A-modified CircEPHB4 in glioma pathogenesis: Insights into cancer stemness metastasis

OBJECTIVE

While existing literature has provided insights into involvement of circEPHB4, SOX2 in glioma, their precise molecular mechanisms and synergistic implications in glioma pathogenesis still dim. This study aims to investigate significance and underlying mechanism of m6A-modified circEPHB4 in regulating SOX2/PHLDB2 axis in gliomas.

METHODS

The mRNA and protein expression were tested by qRT-PCR and Western blot, respectively. ChIP assay was performed to detect SOX2 enrichment on the PHLDB2 promoter. Cell sphere-forming assay to detect self-renewal ability, flow cytometry to determine positivity of CD133 expressions, Malignant behavior of glioma cells were detected by CCK-8, plate colony formation, scratch, and transwell assays. Glioma xenograft models were constructed to investigate effects of CircEPHB4 in tumor development in vivo.

RESULTS

Methyltransferase MELLT3 upregulated m6A modification of CircEPHB4, and YTHDC1 promoted cytoplasmic localization of m6A-modified CircEPHB4. Overexpression of wild-type CircEPHB4 enhanced glioma cells' stemness, metastasis, and proliferation. Cytoplasmic CircEPHB4 increased SOX2 mRNA stability by binding to IGF2BP2, and the effects observed by SOX2 knockdown were reversed by CircEPHB4 in glioma cells. SOX2 promoted transcriptional expression of PHLDB2 by enriching the PHLDB2 promoter region. SOX2 reversed the inhibition of PHLDB2 knockdown on stemness of glioma, cell proliferation, and metastasis. In vivo experiments also revealed that CircEPHB4 upregulated PHLDB2 expression by stabilizing SOX2 mRNA, which promoted in vivo tumor growth and accelerated stemness of glioma cells and metastasis.

CONCLUSION

This study reveals functional interaction and molecular mechanisms of m6A-modified circEPHB4 in regulating SOX2/PHLDB2 axis, highlighting their importance in glioma pathogenesis and potential as therapeutic targets.

miR-325-3p Reduces Proliferation and Promotes Apoptosis of Gastric Cancer Cells by Inhibiting Human Antigen R

Human antigen R (HuR), also known as ELAVL1, is a widely expressed RNA-binding protein (RBP) that has a significant impact on the development and advancement of tumors. Our previous study found that 5-fluorouracil (5-FU) may impede the proliferation and increase apoptosis in gastric cancer cells by reducing the nucleocytoplasmic shuttling of HuR. However, how posttranscriptional regulation influences HuR functions in gastric cancer remains to be elucidated. Here, we demonstrated that miR-325-3p has the potential to regulate the expression level of HuR by directly binding to its 3'UTR, which in turn led to a significant reduction in proliferation and an increase in apoptosis in gastric cancer cells. In addition, xenograft experiment showed that knockdown of HuR or overexpression of miR-325-3p group exhibited smaller tumor sizes after transplant of gastric cancer cells into zebrafish larvae. Thus, our findings offer new insights into the pathogenesis of gastric cancer and may potentially assist in identifying novel targets for drug therapy.

LncRNA NR2F1-AS1 as a potential biomarker for prognosis in cancer patients: meta and bioinformatics analysis

BACKGROUND

Previous studies have shown that the differential expression of lncRNA NR2F1-AS1 is closely related to the prognosis of cancer, but the conclusion is still controversial. Therefore, we conducted a meta-analysis and bioinformatics analysis to explore the correlation between LncRNA NR2F1-AS1 and cancer prognosis.

METHODS

From the beginning to January 25, 2023, we searched for correlational studies on PubMed, Embase, the Cochrane Library, and Web of Science. We used pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) to determine the importance of LncRNA NR2F1-AS1 for survival and clinicopathological features of human cancers.

RESULTS

The meta-analysis of 637 patients in the 11 included articles showed that upregulation of LncRNA NR2F1-AS1 was associated with shorter overall survival (HR = 1.46,95%Cl 1.06-2.01, p = 0.02) in cancer patients. In addition, overexpression of LncRNA NR2F1-AS1 predicted TNM tumor stage (OR = 3.37, 95%Cl 2.07-5.48, p < 0.00001), and Distant metastasis (OR = 0.18, 95%Cl 0.06-0.48, p = 0.0007). However, the difference in age (OR = 1.10,95%Cl 0.71-1.71, p = 0.67), gender (OR = 1.26,95%Cl 0.79-2.00, p = 0.34), Lymph node metastasis (OR = 1.44,95%Cl 0.27-7.80, p = 0.67) or larger tumor size (OR = 1.56,95%Cl 0.48-5.08, p = 0.46) was not statistically significant.

CONCLUSION

Upregulation of LncRNA NR2F1-AS1 was associated with poor prognosis and advanced clinicopathologic features of tumor patients.

Circ-E-Cad encodes a protein that promotes the proliferation and migration of gastric cancer via the TGF-β/Smad/C-E-Cad/PI3K/AKT pathway

Accumulating studies indicate that circular RNAs (circRNAs) play critical roles in cancer progression. Most of them have been reported to act as microRNA sponges or interact with RNA-binding proteins; however, their full range of functions remains largely unclear. Recently, an increasing number of circRNAs have been found to encode proteins. C-E-Cad, a protein encoded by circular E-cadherin (circ-E-Cad), has been shown to have a great influence in the progression of glioblastoma, but its specific role in gastric cancer (GC) is unclear. Here, we found that both circ-E-Cad and C-E-Cad were upregulated in GC cell lines and GC tissues compared with a human gastric epithelial cell line (GES-1) and normal tissues. Knockdown of circ-E-Cad suppressed GC cell line proliferation and metastasis in vitro and in vivo, whereas overexpression of C-E-Cad had the opposite effects. Immunoblotting revealed that C-E-Cad exerted tumor-promoting functions by regulating the PI3K/AKT pathway. A rescue experiment showed that C-E-Cad but not circ-E-Cad was the executor of protumor biological functions. In addition, we demonstrated that the C-E-Cad expression level could have been increased by the TGF-β/Smad pathway. In summary, our results indicated that the TGF-β/Smad pathway could increase the expression of C-E-Cad to regulate GC cell proliferation, migration, and epithelial-mesenchymal transition by affecting PI3K/AKT signaling.

LncRNA NR2F1-AS1 was involved in azacitidine resistance of THP-1 cells by targeting IGF1 with miR-483-3p

BACKGROUND

The long noncoding RNAs' (lncRNAs) effect on cancer therapy resistance by targeting microRNA (miRNA) in the regulation of drug resistance genes has attracted more and more attention. This study attempted to explore the mechanism of "lncRNA NR2F1-AS1/miR-483-3p/IGF1″ axis in azacitidine resistance of THP-1 cells.

METHODS

THP-1 cells were treated with azacitidine to construct THP1-Aza cells. Cell number and morphological changes were observed by a microscope. CCK8, flow cytometry and transwell were used to detect cell proliferation, apoptosis, cycle, invasion and migration. The targeting relationships between NR2F1-AS1 and miR-483-3p, IGF1 and miR-483-3p were analyzed by dual-luciferase, respectively. RIP assay was applied to verify the interaction between NR2F1-AS1 and miR-483-3p. The relative mRNA expression levels of miR-483-3p, AKT1, PI3K, NR2F1-AS1 and IGF1 were detected by qRT-PCR. PI3K, p-PI3K, AKT, p-AKT and IGF1 protein expression were detected by western blot.

RESULTS

Compared with THP-1 cells, NR2F1-AS1 and IGF1 were highly expressed in THP1-Aza cells, and the miR-483-3p expression was significantly decreased in THP1-Aza cells. Knockdown of NR2F1-AS1 increased apoptosis and G1 phase, and reduced cells growth, invasion and migration ability of THP1-Aza cells. Dual-luciferase demonstrated that NR2F1-AS1 could bind to miR-483-3p, and miR-483-3p could bind to IGF1. RIP assay verified the interaction between NR2F1-AS1 and miR-483-3p. Compared with the si-NR2F1-AS1 group, miR-483-3p inhibitor or oe-IGF1 treatment reduced the apoptosis and cell cycle, and increased the cell growth, invasion and migration ability of THP-1-Aza cells.

CONCLUSION

LncRNA NR2F1-AS1 affects the sensitivity of THP-1 cells to azacitidine resistance by regulating the miR-483-3p/IGF1 axis, which may be a potential target for the treatment of acute monocytic leukemia.

A review on the role of NR2F1-AS1 in the development of cancer

NR2F1-AS1 is a natural antisense transcript with prominent roles in the carcinogenesis. It acts as an oncogene in almost all types of cancers except for cervical and colorectal cancers. It can act as a molecular sponge for miR-17, miR-371a-3p, miR-363, miR-29a-3p, miR-493-5p, miR-190a, miR-140, miR-642a, miR-363, miR-493-5p, miR-483-3p, miR-485-5p, miR-146a-5p, miR-877-5p, miR-338-3 P and miR-423-5p to influence expression of several cancer-related genes. Thus, the sponging role of NR2F1-AS1 is the most appreciated route of its contribution in the carcinogenesis. In addition, NR2F1-AS1 affects activity of IGF-1/IGF-1R/ERK, PI3K/AKT/GSK-3β and Hedgehog pathways. The current narrative review aims at summarization of the results of studies that highlighted the role of NR2F1-AS1 in the carcinogenesis.

The lncRNA-miRNA-integrin alpha V ceRNA network can affect the occurrence and prognosis of gastric cancer

OBJECTIVES

The aim of this study was to explore the role of integrin alpha V (ITGAV) and the related long noncoding RNA-microRNA-messenger RNA competing endogenous RNA (lncRNA-miRNA-mRNA ceRNA) network in the development and prognosis of cancers, especially gastric cancer (GC), through bioinformatic analysis.

METHODS

Pan-cancer and GC data were collected from the UCSC Xena website, and validation datasets were obtained from the Gene Expression Omnibus (GEO). R (version 3.6.3), GraphPad Prism 8, and SPSS 23.0 software were used to analyze data and prepare figures.

RESULTS

The expression of ITGAV in tumor tissues was higher than that of normal tissues in ten cancer types. A lower expression of ITGAV in five tumors (CESC, LGG, LIHC, MESO, and STAD) predicted better patient prognosis. In GC, the mRNA and protein expression of ITGAV in tumor tissues was higher than that of normal tissues. Patients with high ITGAV expression had poor prognosis and clinical characteristics, including worse grades and more advanced stages. Patients with higher ITGAV expression had higher immune and stromal scores and lower purity (P<0.05). In addition, seven miRNAs were found that were negatively correlated with ITGAV expression through the website; high expression of these miRNAs indicated a better prognosis. Using this correlation, the authors built the lncRNA-miRNA-ITGAV ceRNA network, to predict the prognosis of GC.

CONCLUSIONS

This study showed that ITGAV could be considered a prognostic factor for GC, and an lncRNA-miRNA-ITGAV ceRNA network was built to promote the exploration of the mechanism and prognosis of GC.

Epithelial-mesenchymal transition-related long noncoding RNAs in gastric carcinoma

As an evolutionarily phenotypic conversion program, the epithelial-mesenchymal transition (EMT) has been implicated in tumour deterioration and has facilitated the metastatic ability of cancer cells via enhancing migration and invasion. Gastric cancer (GC) remains a frequently diagnosed non-skin malignancy globally. Most GC-associated mortality can be attributed to metastasis. Recent studies have shown that EMT-related long non-coding RNAs (lncRNAs) play a critical role in GC progression and GC cell motility. In addition, lncRNAs are associated with EMT-related transcription factors and signalling pathways. In the present review, we comprehensively described the EMT-inducing lncRNA molecular mechanisms and functional perspectives of EMT-inducing lncRNAs in GC progression. Taken together, the statements of this review provided a clinical implementation in identifying lncRNAs as potential therapeutic targets for advanced GC.

E-Cadherin-Deficient Cells Are Sensitive to the Multikinase Inhibitor Dasatinib

The CDH1 gene, encoding the cell adhesion protein E-cadherin, is one of the most frequently mutated genes in gastric cancer and inactivating germline CDH1 mutations are responsible for the cancer syndrome hereditary diffuse gastric cancer (HDGC). CDH1-deficient gastric cancers exhibit high AKT serine/threonine kinase 3 (AKT3) expression, but specific drugs against this AKT isoform are not available. We therefore used two publicly available datasets to identify AKT3-associated genes which could be used to indirectly target AKT3. Reactome analysis identified an enrichment of extracellular matrix remodelling genes in AKT3-high gastric cancers. Of the 51 genes that were significantly correlated with AKT3 (but not AKT1), discoidin domain receptor tyrosine kinase 2 (DDR2) showed the strongest positive association. Treatment of isogenic human cells and mouse gastric and mammary organoids with dasatinib, a small molecule inhibitor of multiple kinases including SRC, BCR-ABL and DDR2, preferentially slowed the growth and induced apoptosis of E-cadherin-deficient cells. Dasatinib treatment also preferentially slowed the growth of gastric and mammary organoids harbouring both Cdh1 and Tp53 mutations. In organoid models, dasatinib treatment was associated with decreased phosphorylation of total AKT, with a stronger effect seen in Cdh1-deficient organoids. Treatment with combinations of dasatinib and an inhibitor of AKT, MK2206, enhanced the effect of dasatinib in breast MCF10A cells. In conclusion, targeting the DDR2-SRC-AKT3 axis with dasatinib represents a promising approach for the chemoprevention and chemotherapy of gastric and breast cancers lacking E-cadherin.

Hypoxia-induced long noncoding RNA NR2F1-AS1 maintains pancreatic cancer proliferation, migration, and invasion by activating the NR2F1/AKT/mTOR axis

Accumulating evidence has demonstrated the essential role of long noncoding RNAs (lncRNAs) in various types of human cancer, including pancreatic cancer (PC). However, the functions and regulatory mechanisms of nuclear receptor subfamily 2 group F member 1 antisense RNA 1 (NR2F1-AS1) that are responsible for its role in the malignant progression of PC cells remains to be investigated. In this study, the biological effects of NR2F1-AS1 and NR2F1 in PC were investigated by in vitro and in vivo experiments. The mechanisms of NR2F1-AS1 were monitored by bioinformatic predictive analysis and confirmatory experiments. Our results indicated that NR2F1-AS1 was overexpressed and positively correlated with poor survival in PC. Depletion of NR2F1-AS1 restrained PC cell proliferation, migration, invasion, and suppressed xenograft tumor growth and metastasis in vitro and in vivo. Mechanistic experiments suggested that NR2F1-AS1 positively regulated the neighboring NR2F1 gene, which subsequently activated AKT/mTOR signaling, resulting in the upregulation of hypoxia-inducible factor-1α (HIF-1α). Further investigations elucidated that NR2F1-AS1 expression was transcriptionally regulated by HIF-1α under hypoxia. These findings demonstrated that hypoxia-induced NR2F1-AS1 expression directly increased NR2F1 levels to promote PC cell proliferation, migration, and invasion by activating AKT/mTOR signaling. Together, these findings suggest that NR2F1-AS1 could be a prospective therapeutic target for PC.

N(6)-adenosine-methyltransferase-14 promotes glioma tumorigenesis by repressing argininosuccinate synthase 1 expression in an m6A-dependent manner

Glioma is one of the leading causes of tumor-related deaths worldwide, but its potential mechanism remains unclear. This study aimed to explore the biological role and potential mechanism of argininosuccinate synthase 1 (ASS1) in glioma. The relative expression levels of ASS1 in glioma specimens and cell lines were calculated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blotting. The biological functions of ASS1 were demonstrated using the 5-ethynyl-2'-deoxyuridine (EdU) assay, transwell assay, and in vivo experiments. In addition, methylated RNA immunoprecipitation (MeRIP), RNA immunoprecipitation (RIP), and luciferase reporter assays were performed to explore the molecular mechanism of ASS1 in glioma. ASS1 expression levels were found to be downregulated in glioma specimens and cell lines. Functionally, we confirmed that ASS1 inhibited glioma cell proliferation, migration, invasion, and growth both. Furthermore, we found that ASS1 was a target of N(6)-adenosine-methyltransferase-14 (METTL14)-mediated N6-methyladenosine (m6A) modification. Overexpression of METTL14 markedly elevated ASS1 mRNA m6A modification and suppressed ASS1 mRNA expression. We also revealed that METTL14-mediated ASS1 mRNA degradation relied on the YTH m6A RNA-binding protein 2 (YTHDF2)-dependent pathway. We confirmed that decreased ASS1 expression promoted the cell proliferation, migration, and invasion in glioma, and that the METTL14/ASS1/YTHDF2 regulatory axis may be an effective therapeutic target for glioma.