Blocking MIR155HG/miR-155 axis inhibits mesenchymal transition in glioma

MicroRNA-146 family: Molecular insights into their role in regulation of signaling pathways in glioma progression

Glioma is a highly lethal brain cancer in humans. Despite advancements in treatment, the prognosis for patients remains unfavorable. Epigenetic factors, along with their interactions and non-coding RNAs (ncRNAs), are crucial in glioma cells' development and aggressive characteristics. MicroRNAs (miRNAs) are a class of small non-coding RNAs (ncRNAs) that modulate the expression of various genes by binding to target mRNA molecules. They play a critical role in regulating essential biological mechanisms such as cell proliferation and differentiation, cell cycle, and apoptosis. MiR-146a/miR-146b is a significant and prevalent miRNA whose expression alterations are linked to various pathological changes in cancer cells, as well as the modulation of several cellular signaling pathways, including NF-κB, TGF-β, PI3K/Akt, and Notch-1. Scientists may identify novel targets in clinical settings by studying the complicated link between Mir-146a/mir-146b, drug resistance, molecular pathways, and pharmacological intervention in gliomas. Additionally, its interactions with other ncRNAs, such as circular RNA and long non-coding RNA, contribute to the pathogenesis of glioma. As well as miR-146 holds potential as both a diagnostic and therapeutic biomarker for patients with this condition. In the current review, we investigate the significance of miRNAs in the context of glioma, with a particular focus on the critical role of Mir-146a/mir-146b in glioma tumors. Additionally, we examined the clinical relevance of this miRNA, highlighting its potential implications for diagnosis and treatment.

miR-3154 promotes glioblastoma proliferation and metastasis via targeting TP53INP1

Glioblastomas (GBM) are most common types of primary brain tumors and miRNAs play an important role in pathogenesis of glioblastomas. Here, we reported a new miRNA, miR-3154, which regulates glioblastoma proliferation and metastasis. miR-3154 was elevated in glioblastoma tissue and cell lines, and its elevation was associated with grade of glioblastomas. Knockdown of miR-3154 in cell lines weakened ability of proliferation and colony formation, and caused cell cycle arrested and higher percentage of apoptosis. Knockdown of miR-3154 also impaired ability of migration and invasion in glioblastoma cells. In mechanism, miR-3154 bound directly to Tumor Protein P53 Inducible Nuclear Protein 1 (TP53INP1), down-regulating TP53INP1 expression at both mRNA and protein level. Silence of TP53INP1 reversed the effect of miR-3154 knockdown on proliferation and metastasis of glioblastoma cells. These findings show that miR-3154 promotes glioblastoma proliferation and metastasis via targeting TP53INP1.

MiR-155-5p regulates autophagy and apoptosis of glioma cells through RICTOR

Background

Glioma characterized by the high degree of drug resistance and the poor prognosis is the most common primary malignant tumors of the brain. And miRNA is involved in a variety of biological behaviors of tumors, enhancing or inhibiting the occurrence and development of tumors. Therefore, the present study aims to explore whether miR-155-5p can regulate autophagy and apoptosis of glioma through RICTOR.

Methods

The significantly differential gene miR-155-5p was identified from the Gene Expression Omnibus (GEO; http://www.ncbi.nlm.nih.gov/geo) databases GSE165937 and GSE138764 using bioinformatics analysis, and its expression was validated by quantitative real-time polymerase chain reaction (qRT-PCR). The putative target genes of miR-155-5p were predicted through interrogation of relevant databases, followed by identification of key target genes. Subsequently, core target genes were selected for functional enrichment analysis. The U87MG cell line was utilized as the experimental model and divided into Negative Control1 (NC1) group, Mimic group, Negative Control2 (NC2) group, Inhibitor group, and NC + 3-methyladenine (3-MA) group. The expression levels of miR-155-5p, RICTOR, P62, LC-3, Bax, Bcl-2, and Caspase-3 were assessed using qRT-PCR, cellular fluorescence imaging, and Western blotting; while apoptosis in the U87MG cell line was evaluated via flow cytometry.

Results

The results showed that miR-155-5P was highly expressed in glioma cells, which could inhibit the expression of Bax, Caspase-3, LCII/LCI and Beclin-1, and increase the expression of Bcl2 and P62. Flow cytometry and cell fluorescence were used to verify the above results. Moreover, when U87MG cells treated with miR-155-5p inhibitor were inhibited by 3-MA, the results showed that miR-155-5p enhanced the anti-apoptotic ability of U87MG cells by regulating autophagy. In addition, the bioinformatics results show that miR-155-5p survival prognosis in glioma into a strong negative correlation, while the survival prognosis of RICTOR in glioma showed a strong positive correlation. The core target genes Kyoto Encyclopedia of Genes and Genomes (KEGG) mainly occurred in PI3K-AKT signaling pathway; in addition, qRT-PCR and Western blot confirmed the regulatory effect of miR-155-5P on RICTOR.

Conclusions

MiR-155-5p regulates autophagy and apoptosis-related proteins in glioma cells through RICTOR, affecting the occurrence and development of glioma.

Silencing miR-155-5p alleviates hippocampal damage in kainic acid-induced epileptic rats via the Dusp14/MAPK pathway

Epilepsy with recurrent seizures is characterized by neuronal damage and glial proliferation induced by brain inflammation. Recurrent seizures can lead to changes in the microRNA (miRNA) spectrum, significantly influencing the inflammatory response of microglia. MiR-155-5p, as a pro-inflammatory miRNA, is increased in the epileptic brain. However, its specific role in acute seizures remains unknown. The study aimed to develop a new strategy for treating epilepsy by investigating how silencing of miR-155-5p initiated its anticonvulsive mechanism. The level of miR-155-5p was up-regulated in the hippocampus of epileptic immature rats induced by kainic acid (KA). The use of antago-miR-155-5p exerted significant beneficial effects on the seizure scores, brain discharges and cognition in immature rats following KA-induced epilepsy. Antago-miR-155-5p also inhibited neuron damage and microglial activation. Moreover, the silencing of miR-155-5p significantly inhibited the Dual-specificity phosphatase 14 (Dusp14)/ mitogen-activated protein kinase (MAPK) axis in vivo. MiR-155-5p interacted with dusp14 to regulate MAPK signaling way expression, verified by a dual-luciferase reporter assay. The results suggested that the silencing of miR-155-5p might reduce hippocampal damage in epileptic immature rats induced by KA via Dusp14/MAPK signaling way. This implied that miR-155-5p could serve as a therapeutic tool to prevent the development of epilepsy.

Oncogenic roles of long non-coding RNAs in essential glioblastoma signaling pathways

Glioblastoma multiforme (GBM) is an aggressive and diffuse type of glioma with the lowest survival rate in patients. The recent failure of multiple treatments suggests that targeting several targets at once may be a different strategy to overcome GBM carcinogenesis. Normal function of oncogenes and tumor suppressor genes need for the preservation of regular cellular processes, so any defects in these genes' activity, operate the corresponding signaling pathways, which initiate carcinogenic processes. Long non-coding RNAs (lncRNAs) that can be found in the cytoplasm or nucleus of the cells, control the transcription and translation of genes. LncRNAs perform a variety of functions, including epigenetic alteration, protein modification and stability, transcriptional regulation, and competition for miRNA that regulate mRNA translation through sponging miRNAs. Identification of various oncogenic lncRNAs and their multiple roles in brain cancers making them potential candidates for use as glioma diagnostic, prognostic, and therapeutic targets in the future. This study highlighted multiple oncogenic lncRNAs and classified them into different signaling pathways based on the regulated target genes in glioblastoma.

Blocking the MIR155HG/miR-155 axis reduces CTGF-induced inflammatory cytokine production and α-SMA expression via upregulating AZGP1 in hypertrophic scar fibroblasts

Hypertrophic scarring (HS) is a pathological condition characterized by excessive fibrosis and inflammation, resulting in excessive extracellular matrix formation in the skin. MIR155HG, a long non-coding RNA, is abnormally upregulated in fibrotic tissues; however, its underlying mechanism is poorly understood. Using single-cell sequencing data, we analyzed connective tissue growth factor (CTGF) expression in various cell types in HS and normal skin tissues and MIR155HG expression in clinical samples. To investigate the mechanism of fibrosis, an in vitro model using CTGF-treated hypertrophic scar fibroblasts (HSFBs) was established and qRT-PCR, western blotting and ELISA assays were performed to investigate the expression of interleukin (IL)-1β, IL-6, and mesenchymal markers α-smooth muscle actin (α-SMA). CTGF stimulates MIR155HG level through phosphorylated STAT3 binding to the MIR155HG promoter. We analyzed the methylation of MIR155HG, assessed the levels of miR-155-5p/-3p in CTGF-treated HSFBs and identified differentially expressed genes among HS and NS samples using the Gene Expression Omnibus RNA sequencing data. The binding between miR-155-5p/-3p and AZGP1 was confirmed using a dual-luciferase assay and inflammatory cytokine production and α-SMA expression were investigated in rescue experiments. The findings revealed that CTGF elevated inflammatory cytokine production, α-SMA and MIR155HG expression in HSFBs. MIR155HG is upregulated in HS tissues due to low DNA methylation. Mechanistically, miR-155-5p/-3p was directly bound to MIR155HG 3'UTR. MIR155HG silencing inhibited cytokine production and α-SMA expression by repressing the generation of miR-155-5p/-3p in CTGF-treated HSFBs. Bioinformatics analysis and luciferase reporter assays revealed that miR-155-5p/-3p targets AZGP1. In addition, transfection with plasmids carrying AZGP1 cDNA significantly inhibited the signaling activity of miR-155-5p/-3 p-overexpressing HSFBs. Our findings highlight the importance of the MIR155HG/miR-155/AZGP1 axis in regulating cytokine production and α-SMA in HS.

Hypoxia-responsive lncRNA MIR155HG promotes PD-L1 expression in hepatocellular carcinoma cells by enhancing HIF-1α mRNA stability

The microenvironment of hepatocellular carcinoma (HCC) is characterized by hypoxia, which leads to immune evasion of HCC. Therefore, gaining a comprehensive understanding of the mechanism underlying the impact of hypoxia on HCC cells may provide valuable insights into immune checkpoint therapy. Based on analysis of databases and clinical samples, we observed that expression level of programmed cell death ligand 1 (PD-L1) and long non-coding RNA (lncRNA) MIR155HG in patients in the hypoxia group were higher than those in the non-hypoxia group. Furthermore, there was a positive correlation between the expression of PD-L1 and MIR155HG with that of HIF-1α. In vitro experiments using hypoxic treatment demonstrated an increase in PD-L1 and MIR155HG expression levels in HCC cells. While the hypoxia-induced upregulation of PD-L1 could be reversed by knocking down MIR155HG. Mechanistically, as a transcription factor, HIF-1α binds to the promoter region of MIR155HG to enhance its transcriptional activity under hypoxic conditions. Hypoxia acts as a stressor promoting nuclear output of ILF3 leading to increased binding of ILF3 to MIR155HG, thereby enhancing stability for HIF-1α mRNA. In vivo, knocking down MIR155HG inhibit subcutaneous tumor growth, reduce the expression of HIF-1α and PD-L1 within tumors; additionally, it enhances anti-tumor immunity response. These findings suggested that through inducing MIR155HG to interact with ILF3, hypoxia increases HIF-1α mRNA stability resulting in elevated PD-L1 expression in HCC and thus promoting immune escape. In summary, this study provides new insights into the effects of hypoxia on HCC immunosuppression.

From bench to bedside: The promising value of exosomes in precision medicine for CNS tumors

Exosomes are naturally present extracellular vesicles (EVs) released into the surrounding body fluids upon the fusion of polycystic and plasma membranes. They facilitate intercellular communication by transporting DNA, mRNA, microRNA, long non-coding RNA, circular RNA, proteins, lipids, and nucleic acids. They contribute to the onset and progression of Central Nervous System (CNS) tumors. In addition, they can be used as biomarkers of tumor proliferation, migration, and blood vessel formation, thereby affecting the Tumor Microenvironment (TME). This paper reviews the recent advancements in the diagnosis and treatment of exosomes in various CNS tumors, the promise and challenges of exosomes as natural carriers of CNS tumors, and the therapeutic prospects of exosomes in CNS tumors. Furthermore, we hope this research can contribute to the development of more targeted and effective treatments for central nervous system tumors.

Aptamer-RIBOTAC Strategy Enabling Tumor-Specific Targeted Degradation of MicroRNA for Precise Cancer Therapy

MicroRNA (miRNA) molecules play crucial roles in a variety of diseases, making miRNA targeting a burgeoning field in medicinal chemistry. Ribonuclease targeting chimeras (RIBOTACs) present a compelling approach for RNA degradation. However, small molecule-based RIBOTAC requires an expensive and time-consuming screening process, and is difficult to directly target miRNA due to its short length lacking secondary structure. Antisense oligonucleotide (ASO)-based RIBOTAC is easy to design but with poor cell permeability. While both of them lack the specificity for tumor targeting. In this study, the first Aptamer-RIBOTAC (ARIBOTAC) chimera is designed based on ASO to achieve precise degradation of miRNA in a tumor cell-specific manner for precise cancer therapy. This chimera exhibits a remarkable ability to specifically identify and enter cancer cells, trigger localized activation of endogenous RNase L, and selectively cleave miRNAs that are complementary to ASO. The efficacy and universality of the ARIBOTAC strategy both in vitro and in vivo by degrading oncogenic miR-210-3p and miR-155-5p are validated. These findings underscore the potential of the ARIBOTAC strategy as a promising avenue for cancer therapy by precisely targeting cancer-associated miRNAs.

Immunological processes of enhancers and suppressors of long non-coding RNAs associated with brain tumors and inflammation

Immunological processes, such as inflammation, can both cause tumor suppression and cancer progression. Moreover, deregulated levels of long non-coding RNA (lncRNA) expression in the brain may cause inflammation and lead to the growth of tumors. Like other biological processes, the immune system's role in cancer is complicated, varies, and can help or hurt the cancer's maintenance. According to research, inflammation and brain cancer are correlated via several signaling pathways. A variety of lncRNAs have recently been revealed to influence cancer by modulating inflammatory pathways. As a result, lncRNAs have the potential to influence carcinogenesis, tumor formation, or tumor suppression via an increase or decrease in inflammation functions. Although the study and targeting of lncRNAs have made great progress in the treatment of cancer, there are definitely limitations and challenges. Using new technologies like nanocarriers and cell-penetrating peptides (CPPs) to target treatments without hurting healthy body tissues has shown to be very effective. In this review article, we have collected significantly related lncRNAs and their inhibitory or stimulating roles in inflammation and brain cancer for the first time. However, there are limitations, such as side effects and damage to normal tissues. With the advancement of new targeting technologies, these lncRNAs may be candidates for the specific targeting therapy of brain cancers by limiting inflammation or stimulating the immune system against them in the future.

LncRNA-SERB promotes vasculogenic mimicry (VM) formation and tumor metastasis in renal cell carcinoma

A growing body of evidence shows that vasculogenic mimicry (VM) is closely related to the invasion and metastasis of many tumor cells. Although the estrogen receptor (ER) can promote initiation and progression of renal cell carcinoma (RCC), how the downstream biomolecules are involved, and the detailed mechanisms of how ER expression is elevated in RCC remain to be further elucidated. Here, we discovered that long noncoding RNA (LncRNA)-SERB is highly expressed in tumor cells of RCC patients. We used multiple RCC cells and an in vivo mouse model for our study, and results indicated that LncRNA-SERB could boost RCC VM formation and cell invasion in vitro and in vivo. Although a previous report showed that ERβ can affect the VM formation in RCC, it is unclear which factor could upregulate ERβ. This is the first study to show LncRNA-SERB can be the upstream regulator of ERβ to control RCC progression. Mechanistically, LncRNA-SERB may increase ERβ via binding to the promoter area, and ERβ functions through transcriptional regulation of zinc finger E-box binding homeobox 1 (ZEB1) to regulate VM formation. These results suggest that LncRNA-SERB promotes RCC cell VM formation and invasion by upregulating the ERβ/ZEB1 axis and that therapeutic targeting of this newly identified pathway may better inhibit RCC progression.

Alteration of functionality and differentiation directed by changing gene expression patterns in myeloid-derived suppressor cells (MDSCs) in tumor microenvironment and bone marrow through early to terminal phase of tumor progression

Myeloid-derived suppressor cells are heterogenous immature myeloid lineage cells that can differentiate into neutrophils, monocytes, and dendritic cells as well. These cells have been characterized to have potent immunosuppressive capacity in neoplasia and a neoplastic chronic inflammatory microenvironment. Increased accumulation of myeloid-derived suppressor cells was reported with poor clinical outcomes in patients. They support neoplastic progression by abrogating antitumor immunity through inhibition of lymphocyte functions and directly by facilitating tumor development. Yet the shifting genetic signatures of this myeloid lineage cell toward immunosuppressive functionality in progressive tumor development remain elusive. We have attempted to identify the gene expression profile using lineage-specific markers of these unique myeloid lineage cells in a tumor microenvironment and bone marrow using a liquid transplantable mice tumor model to trace the changing influence of the tumor microenvironment on myeloid-derived suppressor cells. We analyzed the phenotype, functional shift, suppressive activity, differentiation status, and microarray-based gene expression profile of CD11b+Gr1+ lineage-specific cells isolated from the tumor microenvironment and bone marrow of 4 stages of tumor-bearing mice and compared them with control counterparts. Our analysis of differentially expressed genes of myeloid-derived suppressor cells isolated from bone marrow and the tumor microenvironment reveals unique gene expression patterns in the bone marrow and tumor microenvironment-derived myeloid-derived suppressor cells. It also suggests T-cell suppressive activity of myeloid-derived suppressor cells progressively increases toward the mid-to-late phase of the tumor and a significant differentiation bias of tumor site myeloid-derived suppressor cells toward macrophages, even in the presence of differentiating agents, indicating potential molecular characteristics of myeloid-derived suppressor cells in different stages of the tumor that can emerge as an intervention target.

Valproic acid regulates the miR-155/Jarid2 axis by affecting miR-155 promoter methylation in glioma

The most frequent primary brain tumor in adults is glioma, yet no effective curative treatments are currently available. Our previous study demonstrated the enhancing effects of JARID2 on glioma sensitivity to TMZ treatment. In this study, miR-155 is predicted to target JARID2. miR-155 is overexpressed in clinical glioma specimens and cell lines. miR-155 overexpression in glioma cells enhances cell viability and represses cell apoptosis. Through targeting, miR-155 inhibits JARID2 expression. miR-155 inhibition inhibits glioma cell viability and enhances cell apoptosis, whereas JARID2 knockdown enhances cell viability and inhibits cell apoptosis; JARID2 knockdown partially reverses miR-155 inhibition effects on glioma phenotypes. miR-155 inhibition reduces but knockdown of JARID2 promotes the tumor formation ability of glioma cells in vivo. Valproic acid (VPA) upregulates JARID2 expression, inhibits glioma cell viability and enhances cell apoptosis. VPA downregulates the expression level of miR-155 by increasing the methylation level of the miR-155 promoter, suggesting that the miR-155/JARID2 axis is implicated in VPA inhibition of glioma cell viability and enhancement of glioma cell apoptosis. This study demonstrates a new mechanism of VPA treatment of gliomas by affecting the miR-155/JARID2 axis, which could be regarded as a new strategy for the prevention and treatment of glioma.

Association of HOTAIR, MIR155HG, TERC, miR-155, -196a2, and -146a Genes Polymorphisms with Papillary Thyroid Cancer Susceptibility and Prognosis

Polymorphisms in long non-coding RNA and microRNA genes may play a significant role in the susceptibility and progression of papillary thyroid carcinoma (PTC). The current study investigates the polymorphisms HOTAIR rs920778, MIR155HG rs1893650, TERC rs10936599, miR-155 rs767649, miR-196a2 rs11614913 and miR-146a rs2910164 in 102 PTC patients and 106 age- and sex-matched controls of the Caucasian Serbian population, using real-time PCR. We observed differences in genotype distributions of the HOTAIR rs920778 (p = 0.016) and MIR155HG rs1893650 (p = 0.0002) polymorphisms between PTC patients and controls. HOTAIR rs920778 was associated with increased PTC susceptibility (adjusted OR = 1.497, p = 0.021), with the TT variant genotype increasing the risk compared to the CC genotype (OR = 2.466, p = 0.012) and C allele carriers (CC + CT) (OR = 1.585, p = 0.006). The HOTAIR rs920778 TT genotype was associated with lymph node metastasis (p = 0.022), tumor recurrence (p = 0.016), and progression-free survival (p = 0.010) compared to C allele carriers. Multivariate Cox regression revealed that ATA risk (HR = 14.210, p = 0.000004) and HOTAIR rs920778 (HR = 2.811, p = 0.010) emerged as independent prognostic factors in PTC. A novel polymorphism, MIR155HG rs1893650, was negatively correlated with susceptibility to PTC, with TC heterozygotes exerting a protective effect (OR = 0.268, p = 0.0001). These results suggest that the polymorphisms HOTAIR rs920778 and MIR155HG rs1893650 could be potential prognostic and risk biomarkers in papillary thyroid carcinomas.

Downregulation of lncRNA SATB2‑AS1 facilitates glioma cell proliferation by sponging miR‑671‑5p

The antisense transcript of SATB2 protein (SATB2-AS1) is a novel long non-coding RNA (lncRNA) which is involved in the development of colorectal cancer, breast cancer and hepatocellular carcinoma. In the present study, it was aimed to investigate the consequent situation of SATB2-AS1 in tissue and cell lines of glioma. The expression of SATB2-AS1 in glioma cases was analyzed in The Cancer Genome Atlas datasets. The glycolytic metabolism was determined in glioma cells by detection of extracellular glucose level, oxygen consumption rate and extracellular acidification rate. Cell Counting Kit-8 assay and flow cytometry were used to assess cell proliferation and apoptosis in glioma cells. The interaction between SATB2-AS1 and microRNA (miR)-671-5p was verified by bioinformatic analysis, reverse transcription-quantitative PCR, dual luciferase reporter assay and RNA immunoprecipitation assay. The expression levels of the downstream targets of SATB2-AS1 were studied by western blotting. Results demonstrated that SATB2-AS1 was a downregulated lncRNA in low grade glioma and glioblastoma. Gain-of-function assay demonstrated that SATB2-AS1 inhibited cell proliferation, and glycolytic metabolism, while induced cell apoptosis in glioma cells. SATB2-AS1 sponged and suppressed the expression of an oncogenic miRNA miR-671-5p. By regulation of miR-671-5p, SATB2-AS1 upregulated cerebellar degeneration related protein 1 (CDR1) and Visinin-like 1 (VSNL1) expression in glioma cells. miR-671-5p overexpression partially reversed the antitumor effect of SATB2-AS1 in glioma. In conclusion, the current study demonstrated that there was a downregulation of SATB2-AS1 in glioma, and SATB2-AS1 regulated miR-671-5p/CDR1 axis and miR-671-5p/VSNL1 axis in glioma.

MicroRNA-155 and cancer metastasis: Regulation of invasion, migration, and epithelial-to-mesenchymal transition

Among the leading causes of death globally has been cancer. Nearly 90% of all cancer-related fatalities are attributed to metastasis, which is the growing of additional malignant growths out of the original cancer origin. Therefore, a significant clinical need for a deeper comprehension of metastasis exists. Beginning investigations are being made on the function of microRNAs (miRNAs) in the metastatic process. Tiny non-coding RNAs called miRNAs have a crucial part in controlling the spread of cancer. Some miRNAs regulate migration, invasion, colonization, cancer stem cells' properties, the epithelial-mesenchymal transition (EMT), and the microenvironment, among other processes, to either promote or prevent metastasis. One of the most well-conserved and versatile miRNAs, miR-155 is primarily distinguished by overexpression in a variety of illnesses, including malignant tumors. It has been discovered that altered miR-155 expression is connected to a number of physiological and pathological processes, including metastasis. As a result, miR-155-mediated signaling pathways were identified as possible cancer molecular therapy targets. The current research on miR-155, which is important in controlling cancer cells' invasion, and metastasis as well as migration, will be summarized in the current work. The crucial significance of the lncRNA/circRNA-miR-155-mRNA network as a crucial regulator of carcinogenesis and a player in the regulation of signaling pathways or related genes implicated in cancer metastasis will be covered in the final section. These might provide light on the creation of fresh treatment plans for controlling cancer metastasis.

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 in vivo and in vitro 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.

The prognostic value and immune landscaps of m6A/m5C-related lncRNAs signature in the low grade glioma

BACKGROUND

N6-methyladenosine (m6A) and 5-methylcytosine (m5C) are the main RNA methylation modifications involved in the oncogenesis of cancer. However, it remains obscure whether m6A/m5C-related long non-coding RNAs (lncRNAs) affect the development and progression of low grade gliomas (LGG).

METHODS

We summarized 926 LGG tumor samples with RNA-seq data and clinical information from The Cancer Genome Atlas and Chinese Glioma Genome Atlas. 105 normal brain samples with RNA-seq data from the Genotype Tissue Expression project were collected for control. We obtained a molecular classification cluster from the expression pattern of sreened lncRNAs. The least absolute shrinkage and selection operator Cox regression was employed to construct a m6A/m5C-related lncRNAs prognostic signature of LGG. In vitro experiments were employed to validate the biological functions of lncRNAs in our risk model.

RESULTS

The expression pattern of 14 sreened highly correlated lncRNAs could cluster samples into two groups, in which various clinicopathological features and the tumor immune microenvironment were significantly distinct. The survival time of cluster 1 was significantly reduced compared with cluster 2. This prognostic signature is based on 8 m6A/m5C-related lncRNAs (GDNF-AS1, HOXA-AS3, LINC00346, LINC00664, LINC00665, MIR155HG, NEAT1, RHPN1-AS1). Patients in the high-risk group harbored shorter survival times. Immunity microenvironment analysis showed B cells, CD4 + T cells, macrophages, and myeloid-derived DC cells were significantly increased in the high-risk group. Patients in high-risk group had the worse overall survival time regardless of followed TMZ therapy or radiotherapy. All observed results from the TCGA-LGG cohort could be validated in CGGA cohort. Afterwards, LINC00664 was found to promote cell viability, invasion and migration ability of glioma cells in vitro.

CONCLUSION

Our study elucidated a prognostic prediction model of LGG by 8 m6A/m5C methylated lncRNAs and a critical lncRNA regulation function involved in LGG progression. High-risk patients have shorter survival times and a pro-tumor immune microenvironment.

LncRNA MIR155HG Overexpression Promotes Proliferation, Migration, and Chemoresistance in Gastric Cancer Cells

Long non-coding RNAs are thought to play a vital role in a variety of human malignancies. Studies have shown that MIR155 host gene (MIR155HG) acts as an oncogene in several cancers, but the function and its mechanism of MIR155HG in gastric cancer (GC) is still poorly understood. In this study, we determined the biological functions and underlying mechanisms of MIR155HG in GC cells. We found that expression levels of MIR155HG was increased markedly in GC patients' serum. In vitro and in vivo studies demonstrated that MIR155HG modulated the malignant phenotype of GC cells, such as cell proliferation, colony forming ability, cell migration ability, and tumor growth in nude mice. Next, our results revealed that NF-κB and STAT3 signaling pathways could be involved in regulating the malignant behavior of GC cells. Our rescue experiments showed that inhibiting NF-κB and STAT3 signaling pathways attenuated the phenotypes caused by MIR155HG overexpression. Moreover, cytotoxicity and apoptosis assays revealed overexpression of MIR155HG reduced the apotosis of GC cells induced by cisplatin and 5-FU. Together, our studies suggested that MIR155HG overexpression promoted proliferation, migration, and chemoresistance of GC cells. These results might provide a lncRNA-based target for GC treatment in future.

MIR497HG-Derived miR-195 and miR-497 Mediate Tamoxifen Resistance via PI3K/AKT Signaling in Breast Cancer

Tamoxifen is commonly used for the treatment of patients with estrogen receptor-positive (ER+) breast cancer, but the acquired resistance to tamoxifen presents a critical challenge of breast cancer therapeutics. Recently, long noncoding RNA MIR497HG and its embedded miR-497 and miR-195 are proved to play significant roles in many types of human cancers, but their roles in tamoxifen-resistant breast cancer remain unknown. The results indicate that MIR497HG deficiency induces breast cancer progression and tamoxifen resistance by inducing downregulation of miR-497/195. miR-497/195 coordinately represses five positive PI3K-AKT regulators (MAP2K1, AKT3, BCL2, RAF1, and CCND1), resulting in inhibition of PI3K-AKT signaling, and PI3K-AKT inhibition in tamoxifen-resistant cells restored tamoxifen responsiveness. Furthermore, ER α binds the MIR497HG promoter to activate its transcription in an estrogen-dependent manner. ZEB1 interacts with HDAC1/2 and DNMT3B at the MIR497HG promoter, resulting in promoter hypermethylation and histone deacetylation. The findings reveal that ZEB1-induced MIR497HG depletion contributes to breast cancer progression and tamoxifen resistance through PI3K-AKT signaling. MIR497HG can be used as a biomarker for predicting tamoxifen sensitivity in patients with ER+ breast cancer.

LncRNAs in colorectal cancer: Biomarkers to therapeutic targets

Colorectal cancer (CRC) is the third leading cause of cancer-related death in men and women worldwide. As early detection is associated with lower mortality, novel biomarkers are urgently needed for timely diagnosis and appropriate management of patients to achieve the best therapeutic response. Long noncoding RNAs (lncRNAs) have been reported to play essential roles in CRC progression. Accordingly, the regulatory roles of lncRNAs should be better understood in general and for identifying diagnostic, prognostic and predictive biomarkers in CRC specifically. In this review, the latest advances on the potential diagnostic and prognostic lncRNAs as biomarkers in CRC samples were highlighted, Current knowledge on dysregulated lncRNAs and their potential molecular mechanisms were summarized. The potential therapeutic implications and challenges for future and ongoing research in the field were also discussed. Finally, novel insights on the underlying mechanisms of lncRNAs were examined as to their potential role as biomarkers and therapeutic targets in CRC. This review may be used to design future studies and advanced investigations on lncRNAs as biomarkers for the diagnosis, prognosis and therapy in CRC.

Microglia and Brain Macrophages as Drivers of Glioma Progression

Evidence is accumulating that the tumour microenvironment (TME) has a key role in the progression of gliomas. Non-neoplastic cells in addition to the tumour cells are therefore finding increasing attention. Microglia and other glioma-associated macrophages are at the centre of this interest especially in the context of therapeutic considerations. New ideas have emerged regarding the role of microglia and, more recently, blood-derived brain macrophages in glioblastoma (GBM) progression. We are now beginning to understand the mechanisms that allow malignant glioma cells to weaken microglia and brain macrophage defence mechanisms. Surface molecules and cytokines have a prominent role in microglia/macrophage-glioma cell interactions, and we discuss them in detail. The involvement of exosomes and microRNAs forms another focus of this review. In addition, certain microglia and glioma cell pathways deserve special attention. These "synergistic" (we suggest calling them "Janus") pathways are active in both glioma cells and microglia/macrophages where they act in concert supporting malignant glioma progression. Examples include CCN4 (WISP1)/Integrin α6β1/Akt and CHI3L1/PI3K/Akt/mTOR. They represent attractive therapeutic targets.

Lipopolysaccharide facilitates immune escape of hepatocellular carcinoma cells via m6A modification of lncRNA MIR155HG to upregulate PD-L1 expression

Recent studies have suggested that the initiation and progression of hepatocellular carcinoma (HCC) are closely associated with lipopolysaccharide (LPS) of intestinal bacteria. However, the role of LPS in immune regulation of HCC remains largely unknown. An orthotopic Hepa1-6 tumor model of HCC was constructed to analyze the effect of LPS on the expression of immune checkpoint molecules PD-1 and PD-L1. Then we verified the regulation of PD-L1 by LPS in HCC cells. Based on the previous finding that lncRNA MIR155HG regulates PD-L1 expression in HCC cells, we analyzed the relationship of LPS signaling pathway molecules with PD-L1 and MIR155HG by bioinformatics. The molecular mechanism of MIR155HG regulating PD-L1 expression induced by LPS was investigated by RNA pull-down followed by mass spectrometry, RNA immunoprecipitation, fluorescence in situ hybridization, and luciferase reporter assay. Finally, the HepG2 xenograft model was established to determine the role of MIR155HG on PD-L1 expression in vivo. We showed that LPS induced PD-1 and PD-L1 expression in mouse tumor tissues and induced PD-L1 expression in HCC cells. Mechanistically, upregulation of METTL14 by LPS promotes the m6A methylation of MIR155HG, which stabilizes MIR155HG relying on the "reader" protein ELAVL1 (also known as HuR)-dependent pathway. Moreover, MIR155HG functions as a competing endogenous RNA (ceRNA) to modulate the expression of PD-L1 by miR-223/STAT1 axis. Our results suggested that LPS plays a critical role in immune escape of HCC through METTL14/MIR155HG/PD-L1 axis. This study provides a new insight for understanding the complex immune microenvironment of HCC. 1. LPS plays a critical role in immune escape of HCC, especially HCC with cirrhosis. 2. Our study reveals that LPS regulates PD-L1 by m6A modification of lncRNA in HCC. 3. MIR155HG plays an important role in LPS induced PD-L1 expression. 4. LPS-MIR155HG-PD-L1 regulatory axis provides a new target for the treatment of HCC.

The effect of lncRNA MIR155HG-modified MSCs and exosome delivery to synergistically attenuate vein graft intimal hyperplasia

Background

The mesenchymal stem cells (MSCs) were used to repair tissue injury. However, the treatment effect was not satisfactory. We investigated whether lncRNA MIR155HG could promote survival and migration of MSCs under oxidative stress, which mimics in vivo environments. Furthermore, we studied the protective effect of exosomes secreted by MSCs transfected with MIR155HG on endothelial cells. This study aimed to determine whether exploiting MSCs and exosomes modified with lncRNA MIR155HG would exert synergistic therapeutic effect to attenuate vein graft intimal hyperplasia more effectively.

Methods

Lentivirus containing lncRNA MIR155HG overexpressing vector was packaged and used to infect MSCs. Then, CCK-8 assay, flow cytometry, Transwell assay, and Elisa assay were used to assess the functional changes of MSCs with overexpressed MIR155HG (OE-MSCs). Furthermore, the associated pathways were screened by Western blot. MIR155HG-MSCs-derived exosomes (OE-exo) were collected and co-cultured with human umbilicus vein endothelial cell (HUVEC). We validated the protective effect of OE-exo on HUVEC. In vivo, both MSCs and exosomes modified with MIR155HG were injected into a vein graft rat model via tail vein. We observed MSCs homing and intimal hyperplasia of vein graft using a fluorescent microscope and histological stain.

Results

Our study found that lncRNA MIR155HG promoted proliferation, migration, and anti-apoptosis of MSCs. NF-κB pathway took part in the regulation process induced by MIR155HG. OE-exo could enhance the activity and healing ability of HUVEC and reduce apoptosis. In vivo, OE-MSCs had a higher rate of homing to vascular endothelium. The combined treatment with OE-MSCs and OE-exo protected vascular endothelial integrity, reduced inflammatory cell proliferation, and significantly attenuated intimal hyperplasia of vein graft.

Conclusion

LncRNA MIR155HG could promote the survival and activity of MSCs, and reduce the apoptosis of HUVECs using exosome delivery. Exploiting MSCs and exosomes modified with MIR155HG could attenuate vein graft intimal hyperplasia more effectively and maximize the surgical effect.

SARS-CoV-2 RNAs are processed into 22-nt vsRNAs in Vero cells

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the global pandemic, resulting in great fatalities around the world. Although the antiviral roles of RNA interference (RNAi) have been well studied in plants, nematodes and insects, the antiviral roles of RNAi in mammalians are still debating as RNAi effect is suspected to be suppressed by interferon (IFN) signaling pathways in most cell types. To determine the role of RNAi in mammalian resistance to SARS-CoV-2, we studied the profiling of host small RNAs and SARS-CoV-2 virus-derived small RNAs (vsRNAs) in the early infection stages of Vero cells, an IFN-deficient cell line. We found that host microRNAs (miRNAs) were dysregulated upon SARS-CoV-2 infection, resulting in downregulation of microRNAs playing antiviral functions and upregulation of microRNAs facilitating viral proliferations. Moreover, vsRNA peaked at 22 nt at negative strand but not the positive strand of SARS-CoV-2 and formed successive Dicer-spliced pattern at both strands. Similar characteristics of vsRNAs were observed in IFN-deficient cell lines infected with Sindbis and Zika viruses. Together, these findings indicate that host cell may deploy RNAi pathway to combat SARS-CoV-2 infection in IFN-deficient cells, informing the alternative antiviral strategies to be developed for patients or tissues with IFN deficiency.

Upregulation of Spinal miR-155-5p Contributes to Mechanical Hyperalgesia by Promoting Inflammatory Activation of Microglia in Bone Cancer Pain Rats

Bone cancer pain (BCP) seriously deteriorates the life quality of patients, but its underlying mechanism is still unclear. Spinal microRNAs might contribute to the development of BCP and the role of microglial activation is controversial. In this study, we established a BCP model by injecting Walker 256 breast carcinoma cells into the tibial intramedullary cavity of rats and significant hyperalgesia was observed in the BCP rats. The lumbar spinal cords were harvested to perform RNA sequencing (RNA-seq), and 31 differentially expressed miRNAs (26 upregulated and 5 downregulated) were identified in the BCP rats. Among them, miR-155-5p was significantly upregulated in the BCP rats. Spinal microglial activation was observed during BCP development. miR-155-5p could be expressed in spinal microglia and was significantly upregulated in microglia treated with lipopolysaccharide (LPS) in vitro. Serum/glucocorticoid regulated kinase family member 3 (Sgk3) was predicted to be the possible downstream target of miR-155-5p and this was confirmed using a dual-luciferase reporter assay in vitro. The inhibition of miR-155-5p restored Sgk3-expression-attenuated microglial activation and alleviated hyperalgesia in the BCP rats. In conclusion, spinal miR-155-5p/Sgk3/microglial activation might play an important role in BCP pathogenesis.

Exosome-based strategies for diagnosis and therapy of glioma cancer

Glioblastoma belongs to the most aggressive type of cancer with a low survival rate that is characterized by the ability in forming a highly immunosuppressive tumor microenvironment. Intercellular communication are created via exosomes in the tumor microenvironment through the transport of various biomolecules. They are primarily involved in tumor growth, differentiation, metastasis, and chemotherapy or radiation resistance. Recently several studies have highlighted the critical role of tumor-derived exosomes against immune cells. According to the structural and functional properties, exosomes could be essential instruments to gain a better molecular mechanism for tumor understanding. Additionally, they are qualified as diagnostic/prognostic markers and therapeutic tools for specific targeting of invasive tumor cells such as glioblastomas. Due to the strong dependency of exosome features on the original cells and their developmental status, it is essential to review their critical modulating molecules, clinical relevance to glioma, and associated signaling pathways. This review is a non-clinical study, as the possible role of exosomes and exosomal microRNAs in glioma cancer are reported. In addition, their content to overcome cancer resistance and their potential as diagnostic biomarkers are analyzed.

Exosomal miR-155-5p derived from glioma stem-like cells promotes mesenchymal transition via targeting ACOT12

Tumor-associated exosomes play essential roles in intercellular communication and the foundation of cancer microenvironment in glioma. Many mRNAs, microRNAs (miRNAs) and proteins contained in tumor-associated exosomes can be transferred to recipient cells and contribute to the progression of tumor. Nevertheless, the cellular communication between malignant cells with different heterogeneities or characteristics and resultant tumor progression are still unclear in glioma. Here, we show that exosomes released from glioma stem-like cells (GSCs) contain a significant increasing level of miR-155-5p and could be horizontally transferred to surrounding glioma cells. High expression of miR-155-5p in plasma exosomes from patients was associated with glioma diagnosis and grading. Mechanically, we found that miR-155-5p markedly reduced the expression of acetyl-CoA thioesterase 12 (ACOT12), which played as a tumor suppressor in glioma. Furthermore, mesenchymal transition was significantly promoted in glioma cells treated with GSCs-derived exosomes. In conclusion, GSCs-derived exosomal miR-155-5p play a critical role in glioma progression and facilitating tumor aggressive growth by targeting ACOT12 and promoting mesenchymal transition. Exosomal miR-155-5p is also a potential predictive biomarker for glioma, which may provoke the development of novel diagnostic and therapeutic strategies against glioma.

The Regulatory Effects of MicroRNAs on Tumor Immunity

MicroRNAs are endogenous noncoding small RNAs that posttranscriptionally regulate the expressions of their target genes. Accumulating research shows that miRNAs are crucial regulators of immune cell growth and antitumor immune response. Studies on miRNAs and tumors primarily focus on the tumor itself. At the same time, relatively few studies on the indirect regulatory effects of miRNAs in the development of tumors are achieved by affecting the immune system of tumor hosts and altering their immune responses. This review discusses the influence of miRNAs on the antitumor immune system.

Wnt signaling in colorectal cancer: pathogenic role and therapeutic target

Background

The Wnt signaling pathway is a complex network of protein interactions that functions most commonly in embryonic development and cancer, but is also involved in normal physiological processes in adults. The canonical Wnt signaling pathway regulates cell pluripotency and determines the differentiation fate of cells during development. The canonical Wnt signaling pathway (also known as the Wnt/β-catenin signaling pathway) is a recognized driver of colon cancer and one of the most representative signaling pathways. As a functional effector molecule of Wnt signaling, the modification and degradation of β-catenin are key events in the Wnt signaling pathway and the development and progression of colon cancer. Therefore, the Wnt signaling pathway plays an important role in the pathogenesis of diseases, especially the pathogenesis of colorectal cancer (CRC).

Objective

Inhibit the Wnt signaling pathway to explore the therapeutic targets of colorectal cancer.

Methods

Based on studying the Wnt pathway, master the biochemical processes related to the Wnt pathway, and analyze the relevant targets when drugs or inhibitors act on the Wnt pathway, to clarify the medication ideas of drugs or inhibitors for the treatment of diseases, especially colorectal cancer.

Results

Wnt signaling pathways include: Wnt/β-catenin or canonical Wnt signaling pathway, planar cell polarity (Wnt-PCP) pathway and Wnt-Ca²⁺ signaling pathway. The Wnt signaling pathway is closely related to cancer cell proliferation, stemness, apoptosis, autophagy, metabolism, inflammation and immunization, microenvironment, resistance, ion channel, heterogeneity, EMT/migration/invasion/metastasis. Drugs/phytochemicals and molecular preparations for the Wnt pathway of CRC treatment have now been developed. Wnt inhibitors are also commonly used clinically for the treatment of CRC.

Conclusion

The development of drugs/phytochemicals and molecular inhibitors targeting the Wnt pathway can effectively treat colorectal cancer clinically.

Epigenetic Underpinnings of Inflammation: A Key to Unlock the Tumor Microenvironment in Glioblastoma

Glioblastoma (GBM) is the most common malignant brain tumor in adults, and immunotherapies and genetic therapies for GBM have evolved dramatically over the past decade, but GBM therapy is still facing a dilemma due to the high recurrence rate. The inflammatory microenvironment is a general signature of tumors that accelerates epigenetic changes in GBM and helps tumors avoid immunological surveillance. GBM tumor cells and glioma-associated microglia/macrophages are the primary contributors to the inflammatory condition, meanwhile the modification of epigenetic events including DNA methylation, non-coding RNAs, and histone methylation and deacetylases involved in this pathological process of GBM, finally result in exacerbating the proliferation, invasion, and migration of GBM. On the other hand, histone deacetylase inhibitors, DNA methyltransferases inhibitors, and RNA interference could reverse the inflammatory landscapes and inhibit GBM growth and invasion. Here, we systematically review the inflammatory-associated epigenetic changes and regulations in the microenvironment of GBM, aiming to provide a comprehensive epigenetic profile underlying the recognition of inflammation in GBM.

Andrographolide Suppresses Pyroptosis in Mycobacterium tuberculosis-Infected Macrophages via the microRNA-155/Nrf2 Axis

Tuberculosis (TB) remains a leading threat to public health worldwide with Mycobacterium tuberculosis (Mtb) infections causing long-term abnormal and excessive inflammatory responses, which in turn lead to lung damage and fibrosis, and ultimately death. Host-directed therapy (HDT) has been shown to be an effective anti-TB strategy in the absence of effective anti-TB drugs. Here, we used an in vitro macrophage model of Mtb infection to evaluate the effects of andrographolide (Andro), extracted from Andrographis paniculata, on pyroptosis in Mtb-infected macrophages. We evaluated the molecular mechanisms underlying these outcomes. These evaluations revealed that Andro downregulated the expression of proinflammatory miR-155-5p, which then promoted the expression of Nrf2 to suppress pyroptosis in Mtb-infected macrophages. Further study also demonstrated that siNrf2 could attenuate the inhibitory effect of Andro on TXNIP, validating our mechanistic studies. Thus, our data suggest that Andro may be a potential candidate adjuvant drug for anti-TB therapy as it inhibits pyroptosis in Mtb-infected macrophages, potentially improving clinical outcomes.

miR-155-3p: processing by-product or rising star in immunity and cancer?

MicroRNAs (miRNAs) are key players in gene regulation that target specific mRNAs for degradation or translational repression. Each miRNA is synthesized as a miRNA duplex comprising two strands (5p and 3p). However, only one of the two strands becomes active and is selectively incorporated into the RNA-induced silencing complex in a process known as miRNA strand selection. Recently, significant progress has been made in understanding the factors and processes involved in strand selection. Here, we explore the selection and functionality of the miRNA star strand (either 5p or 3p), which is generally present in the cell at low levels compared to its partner strand and, historically, has been thought to possess no biological activity. We also highlight the concepts of miRNA arm switching and miRNA isomerism. Finally, we offer insights into the impact of aberrant strand selection on immunity and cancer. Leading us through this journey is miR-155, a well-established regulator of immunity and cancer, and the increasing evidence that its 3p strand plays a role in these arenas. Interestingly, the miR-155-5p/-3p ratio appears to vary dependent on the timing of the immune response, and the 3p strand seems to play a regulatory role upon its partner 5p strand.

Long Noncoding RNA MIR122HG Inhibits MAVS-Mediated Antiviral Immune Response by Deriving miR-122 in Miiuy Croaker (Miichthys miiuy)

Long noncoding RNAs (lncRNAs) function as micro regulators to impact gene expression after multiple pathogen infections, which have been largely studied in the last few years. Although lncRNA studies on lower vertebrates have received less attention than those on mammals, current studies suggest that lncRNA plays an important role in the immune response of fish to pathogen infections. Here, we studied the effect of MIR122HG as the host gene of miR-122 and indirectly negatively regulate MAVS-mediated antiviral immune responses in miiuy croaker (Miichthysmiiuy). We found that poly(I:C) significantly increases the host MIR122HG expression. The increased MIR122HG expression inhibited the production of the antiviral immune-related genes IFN-1, ISG15 and Viperin upon SCRV treatment. In addition, MIR122HG can act as a pivotally negative regulator involved in the MAVS-mediated NF-κB and IRF3 signaling pathways, which can effectively avoid an excessive immune response. Additionally, we found that MIR122HG can promote the replication of SCRV. Our study provides evidence about the involvement of lncRNAs in the antiviral immune response of fish and broadens the understanding of the function of lncRNAs as a precursor miRNA in teleost fish.

Oxidative Stress and Inflammation in Cardiovascular Diseases and Cancer: Role of Non-coding RNAs

High oxidative stress, Th1/Th17 immune response, M1 macrophage inflammation, and cell death are associated with cardiovascular diseases. Controlled oxidative stress, Th2/Treg anti-tumor immune response, M2 macrophage inflammation, and survival are associated with cancer. MiR-21 protects against cardiovascular diseases but may induce tumor growth by retaining the anti-inflammatory M2 macrophage and Treg phenotypes and inhibiting apoptosis. Down-regulation of let-7, miR-1, miR-9, miR-16, miR-20a, miR-22a, miR-23a, miR-24a, miR-26a, miR-29, miR-30a, miR-34a, miR-124, miR-128, miR-130a, miR-133, miR-140, miR-143-145, miR-150, miR-153, miR-181a, miR-378, and miR-383 may aid cancer cells to escape from stresses. Upregulation of miR-146 and miR-223 may reduce anti-tumor immune response together with miR-21 that also protects against apoptosis. MiR-155 and silencing of let-7e, miR-125, and miR-126 increase anti-tumor immune response. MiR expression depends on oxidative stress, cytokines, MYC, and TGF-β, and expression of silencing lncRNAs and circ-RNAs. However, one lncRNA or circ-RNA may have opposite effects by targeting several miRs. For example, PVT1 induces apoptosis by targeting miR-16a and miR-30a but inhibits apoptosis by silencing miR-17. In addition, levels of a non-coding RNA in a cell type depend not only on expression in that cell type but also on an exchange of microvesicles between cell types and tumors. Although we got more insight into the function of a growing number of individual non-coding RNAs, overall, we do not know enough how several of them interact in functional networks and how their expression changes at different stages of disease progression.

PD-L1/miR-155 Interplay in Pediatric High-Grade Glioma

High-grade pediatric glioma (p-HGG—WHO 2021, formerly GBM—WHO 2016), as a common, aggressive, and highly lethal primary brain malignancy in adults, accounts for only 3–15% of primary brain tumors in pediatric patients. After leukemia, brain malignancies are the second most common in the pediatric population and first in incidences concerning solid tumors. This study was designed on the basis of 14 pediatric patients hospitalized at Children’s Memorial Health Institute in Warsaw, Poland, due to p-HGG treatment. All the patients had a histopathological diagnosis performed by an experienced neuropathologist according to WHO guidelines (WHO 2016 Grade IV Glioblastoma). A significant correlation was found between the miR-155 concentration and the level of PD-L1 expression in p-HGG tumor tissue. Very few reports have indicated PD-L1 expression in pediatric patients.

The long noncoding RNA MIR122HG is a precursor for miR-122-5p and negatively regulates the TAK1-induced innate immune response in teleost fish

Long noncoding RNAs (lncRNAs) are a diverse subset of RNA species of noncoding transcripts that are usually longer than 200 nt. However, the biological role and function of many lncRNAs have not been fully identified. It has been shown that one potential function of lncRNAs is to act as a precursor miRNA and promote the production of multiple miRNAs. However, the function of the miiuy croaker lncRNA MIR122HG has not been explored. In the present study, we show that this differentially expressed teleost fish lncRNA can act as the host gene of miR-122-5p, regulate its expression, and indirectly regulate the expression of potential inflammatory target protein transforming growth factor-β–activated kinase 1. We show that MIR122HG can negatively regulate the transforming growth factor-β–activated kinase 1–triggered NF-κB and interferon regulatory factor 3 signaling pathways and subsequently attenuate the innate immune response. In addition, MIR122HG can promote the replication of Siniperca chuatsi rhabdovirus and exacerbate the pathological effects caused by viral infection. We conclude that the study of lncRNA–miRNA–mRNA interaction through bioinformatics analysis or experimental-supported analysis can provide information for further elucidation of the functions of fish lncRNAs in innate immunity.

Decreased RNA m6A methylation enhances the process of the epithelial mesenchymal transition and vasculogenic mimicry in glioblastoma

RNA N⁶-methyladenosine (m⁶A) modification is gradually thought to be an active participant in the considerable biological processes of glioblastoma (GB), providing us with a novel insight for exploring this disease. However, the role of RNA m⁶A modification during the epithelial mesenchymal transition (EMT) or vasculogenic mimicry (VM) progression has not been investigated in GB. Here we performed a research to validate the impact exerted by AlkB homolog 5 (ALKBH5), one of "erasers" for RNA m⁶A and methyltransferase-like 3 (METTL3) which adds m⁶A modification to the RNAs on the progression of EMT and VM in GB. In this study, we demonstrate that the m⁶A levels of RNAs were reduced in GB cells and glioma tissues. Patients with high mRNA expression of ALKBH5 acquired relatively shorter median overall survival (OS) time, while patients with relatively high expression of MEETL3 prolonged their disease free survival. ALKBH5 enhanced GB cell proliferation and influenced cell cycle in vitro. Decreased RNA m⁶A methylation enhanced the progression of the EMT and VM in glioblastoma cells. ALKBH5 strengthened glioblastoma growth and enhanced the EMT and VM process of glioblastoma in vivo. Our study uncovers that RNA m⁶A methylation suppresses the process of EMT and VM in glioblastoma, providing a new perspective to seek for a potential therapeutic target for GB.

microRNA-155-3p delivered by M2 macrophages-derived exosomes enhances the progression of medulloblastoma through regulation of WDR82

Objective

Exosomes, membranous nanovesicles, naturally bringing proteins, mRNAs, and microRNAs (miRNAs), play crucial roles in tumor pathogenesis. This study was to investigate the role of miR-155-3p from M2 macrophages-derived exosomes (M2-Exo) in promoting medulloblastoma (MB) progression by mediating WD repeat domain 82 (WDR82).

Methods

miR-155-3p expression was detected by RT-qPCR. The relationship of miR-155-3p with clinicopathological features of MB patients was analyzed. M2-Exo were isolated and identified by TEM, NTA and Western blot. CCK-8 assay, colony formation assay, flow cytometry, wound healing assay, and Transwell assay were performed to explore the role of miR-155-3p-enriched M2-Exo on the progression of MB cells. Luciferase assay were used to identify the relationship between miR-155-3p and WDR82. The effect of miR-155-3p-enriched M2-Exo on tumorigenesis of MB was confirmed by the xenograft nude mice model.

Results

miR-155-3p was up-regulated in MB tissues of patients and MB cell lines. High miR-155-3p expression was correlated with the pathological type and molecular subtype classification of MB patients. WDR82 was a direct target of miR-155-3p. miR-155-3p was packaged into M2-Exo. miR-155-3p-enriched M2-Exo promoted the progression of Daoy cells. miR-155-3p-enriched M2-Exo promoted in vivo tumorigenesis.

Conclusion

The study highlights that miR-155-3p-loaded M2-Exo enhances the growth of MB cells via down-regulating WDR82, which might provide a deep insight into MB mechanism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03156-y.

MicroRNA-155 influences cell damage in ischemic stroke via TLR4/MYD88 signaling pathway

Cerebral ischemic stroke (CIS) is extremely harmful, and its treatment should be underpinned by understanding its pathogenic mechanism. This study was designed to determine the involvement of miR-155 in CIS development via the TLR4/MyD88 signaling pathway. First, we quantified serum miR-155 in patients with CIS and healthy individuals, and found high expression of miR-155 in such patients and a decrease in it in the patients after therapy (P < 0.05). Serum miR-155 demonstrated a favorable function in predicting the development and prognosis of CIS (P < 0.001). We also conducted a mouse assay, and found that knocking out miR-155 can improve the neurological function of mice and suppress protein TLR4 and MyD88 (all P < 0.05). Finally, we carried out a cell assay, and found enhancement in the activity of SH-SY5Y cells, decrease in their apoptosis, and protein TLR4 and MyD88 in them after suppression of miR-155 (all P < 0.05). Furthermore, we also found complete reverse by TLR4/MyD88 pathway inhibitor on the influence of increasing miR-155 on cells (P > 0.05). Therefore, with an increase in cases with CIS, miR-155 takes a part in the development of cell damage by activating TLR4/MyD88, and it is probably the key to diagnosing and treating CIS.

miRNA-338-3p inhibits glioma cell proliferation and progression by targeting MYT1L

Glioma is a common and aggressive primary malignant brain tumor. MicroRNAs (miRNAs) play key roles in the post-transcriptional regulation of gene expression. Currently, miRNAs are considered to be useful biomarkers for the diagnosis and prognosis of glioma. Previously, we screened three differentially expressed miRNAs from Gene Expression Omnibus (GEO) database which included miRNA-338-3p. miRNA-338-3p is involved in tumor development in different cancers. However, in glioma, its function and its underlying mechanism remain unclear. We found that overexpression of miRNA-338-3p suppressed cell proliferation, migration, invasion, and promoted apoptosis of glioma in vitro. Myelin transcription factor 1-like (MYT1L) was found to be a direct target of miRNA-383-3p in glioma cells as the expression of MYT1L was inhibited by overexpressing miRNA-338-3p. Additionally, silencing MYT1L produced similar effects as overexpressing miRNA-338-3p in glioma cells. Overexpression of MYT1L also completely attenuated the inhibitory effect induced by miRNA-338-3p overexpression. These results suggest that the miRNA-338-3p/ MYT1L axis plays a critical role in the progression of glioma. Our study delineates one of the complex molecular mechanisms that drive the growth of glioma and may be useful in finding novel prognostic predictors and treatment targets in glioma. AVAILABILITY OF DATA AND MATERIALS: All data generated or analysed during this study are included in this published article.

c-Myc-activated intronic miR-210 and lncRNA MIR210HG synergistically promote the metastasis of gastric cancer

The relationship between microRNA (miRNA) and hosting long non-coding RNA (lncRNA) remains unclear. Here, the expression levels of microRNA-210 (miR-210) and hosting lncRNA MIR210HG are significantly increased and positively correlated in gastric cancer (GC). Gain- and loss-of-function studies demonstrate that miR-210 and MIR210HG synergistically promote the migration and invasion of GC cells in vitro. Furthermore, GC sublines simultaneously expressing miR-210 and MIR210HG display synergistic promotion of lung metastasis in vivo. Mechanistically, MIR210HG interacts with DExH-box helicase 9 (DHX9) to increase DHX9/c-Jun complex's occupancy on the promoter of matrix metallopeptidases (MMPs), and thus promotes migration and invasion of GC cells. Additionally, miR-210 directly suppresses the expression of dopamine receptor D5 (DRD5), serine/threonine kinase 24 (STK24) and MAX network transcriptional repressor (MNT), resulting in enhanced migration and invasion. Finally, MYC proto-oncogene (c-Myc) transactivates miR-210 and MIR210HG. Overexpression of miR-210 or/and MIR210HG can rescue the inhibitory effect on the migration and invasion by silencing c-Myc. Moreover, c-Myc inhibitor significantly decreases lung metastasis of GC in vivo. Collectively, our findings identify a novel mechanism, by which c-Myc-activated miR-210 and MIR210HG synergistically promote the metastasis of GC.

Long noncoding RNA MIR2187HG suppresses TBK1-mediated antiviral signaling through deriving miR-2187-3p in teleost fish

Long non-coding RNAs (lncRNAs) function as microregulatory factors that influence gene expression after a variety of pathogenic infection, which have been extensively studied in the past few years. Although less attention has been paid to lncRNAs in lower vertebrates than in mammals, current studies reveals that lncRNAs plays a vital role in fish stimulated by pathogens. Here, we discovered a new lncRNA, termed as MIR2187HG, which can function as a precursor of a small RNA miR-2187-3p with regulatory functions in miiuy croaker (Miichthys miiuy). Upon Siniperca chuatsi rhabdovirus (SCRV) virus infection, the expression levels of MIR2187HG were remarkably enhanced. Elevated MIR2187HG expression can act as a pivotally negative regulator that participates in the innate immune response of teleost fish to inhibit the intracellular TANK-binding kinase 1 (TBK1)-mediated antiviral signaling pathways, which can effectively avoid excessive immunity. In addition, we found that the SCRV virus could also utilize MIR2187HG to enhance its own number. Our results not only provide evidence regarding the involvement of the lncRNAs in response to anti-viruses in fish, but also broaden our understanding of the function of lncRNAs as precursor miRNA in teleost fish for the first time. Importance: SCRV infection upregulates MIR2187HG levels, which in turn suppresses SCRV-triggered type I interferon production, thus promoting viral replication in miiuy croaker. Notably, MIR2187HG regulates the release of miR-2187-3p, and TBK1 is a target of miR-2187-3p. MIR2187HG could obtain the function from miR-2187-3p to inhibit TBK1 expression and subsequently modulate TBK1-mediated NF-κB and IRF3 signaling. The collective results suggest that the novel regulation mechanism of TBK1-mediated antiviral response during RNA viral infection was regulated by MIR2187HG. Therefore, a new regulation mechanism for lncRNAs to regulate antiviral immune responses in fish is proposed.

LncRNA MIR155HG induces M2 macrophage polarization and drug resistance of colorectal cancer cells by regulating ANXA2

OBJECTIVE

To investigate the effects of lncRNA MIR155HG and Annexin A2 (ANXA2) on colorectal cancer (CRC) and the mechanism of the MIR155HG/ANXA2 axis.

METHODS

The expressions of MIR155HG and ANXA2 in human CRC tissues were analyzed for association with pathological characteristics and prognosis of CRC patients. CRC cell lines (Caco2 and HT29) were used to study the effects of MIR155HG or ANXA2 knockdown on tumor cell behaviors and macrophage polarization as well as the effect of M2 polarization on oxaliplatin resistance of CRC cells. RNA immunoprecipitation, RNA pull-down and dual-luciferase reporter assays were applied to verify the targeting relationships among MIR155HG, miR-650 and ANXA2. Heterotopic xenograft models were established to verify the results of cell experiments.

RESULTS

MIR155HG and ANXA2 were highly expressed in CRC tissues/cells and of prognostic values for CRC patients. Knockdown of MIR155HG or ANXA2 suppressed M2 macrophage polarization, and proliferation, migration, invasion and oxaliplatin resistance of CRC cells. MIR155HG competed with ANXA2 for binding miR-650 and can also directly target ANXA2. Knockdown of MIR155HG or ANXA2 also inhibited M2 macrophage polarization and CRC progression in nude mice.

CONCLUSION

This study highlighted that MIR155HG, by regulating the miR-650/ANXA2 axis, promotes CRC progression and enhances oxaliplatin resistance in CRC cells through M2 macrophage polarization.

Regulatory interplay between microRNAs and WNT pathway in glioma

Glioma is one of the most common neoplasms of the central nervous system with a poor survival. Due to the obstacles in treating this disease, a part of recent studies mainly focuses on identifying the underlying molecular mechanisms that contribute to its malignancy. Altering microRNAs (miRNAs) expression pattern has been identified obviously in many cancers. Through regulating various targets and signaling pathways, miRNAs play a pivotal role in cancer progression. As one of the essential signaling pathways, WNT pathway is dysregulated in many cancers, and a growing body of evidence emphasis its dysregulation in glioma. Herein, we provide a comprehensive review of miRNAs involved in WNT pathway in glioma. Moreover, we show the interplay between miRNAs and WNT pathway in regulating different processes such as proliferation, invasion, migration, radio/chemotherapy resistance, and epithelial-mesenchymal-transition. Then, we introduce several drugs and treatments against glioma, which their effects are mediated through the interplay of WNT pathway and miRNAs.

Long non-coding RNA miR155HG silencing restrains ovarian cancer progression by targeting the microRNA-155-5p/tyrosinase-related protein 1 axis

Ovarian cancer (OC) is the third commonest gynecological malignancy worldwide. The long non-coding (lnc)RNA microRNA (miR)155HG functions as an oncogene in different human cancers. However, the function and molecular mechanism of miR155HG in OC remain elusive. The present study indicated that the expression levels of miR155HG and tyrosinase-related protein 1 (TYRP1) were significantly increased, whereas that of miR155-5p was decreased in OC tissues and cells, as detected by real-time quantitative polymerase chain reaction. It was demonstrated that knockdown of miR155HG markedly inhibited OC cell viability, migration and invasion while promoting apoptosis, as indicated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, Transwell and western blot assays. Mechanistically, it was revealed that miR155HG and TYRP1 were both targeted by miR-155-5p with complementary binding sites in the 3' untranslated region. A dual-luciferase reporter assay was used to confirm the targeting relationship between miR155HG, miR-155-5p and TYRP1. In addition, the interaction between miR155HG and miR-155-5p was further demonstrated by radioimmunoprecipitation and pull-down assays. In addition, feedback approaches determined that miR-155-5p inhibition or TYRP1 overexpression markedly reversed the inhibitory effects of miR155HG knockdown on OC cell viability, migration and invasion as well as weakened the promotive effect of miR155HG knockdown on OC cell apoptosis. Thus, miR155HG silencing inhibited the malignant biological behavior of OC cells by targeting the miR-155-5p/TYRP1 axis. The present study provides novel insights into the underlying mechanism of OC progression.

Pan-Cancer Analysis Reveals Common and Specific Relationships between Intragenic miRNAs and Their Host Genes

MicroRNAs (miRNAs) are small endogenous non-coding RNAs that play important roles in regulating gene expression. Most miRNAs are located within or close to genes (host). miRNAs and their host genes have either coordinated or independent transcription. We performed a comprehensive investigation on co-transcriptional patterns of miRNAs and host genes based on 4707 patients across 21 cancer types. We found that only 11.6% of miRNA-host pairs were co-transcribed consistently and strongly across cancer types. Most miRNA-host pairs showed a strong coexpression only in some specific cancer types, demonstrating a high heterogenous pattern. For two particular types of intergenic miRNAs, readthrough and divergent miRNAs, readthrough miRNAs showed higher coexpression with their host genes than divergent ones. miRNAs located within non-coding genes had tighter co-transcription with their hosts than those located within protein-coding genes, especially exonic and junction miRNAs. A few precursor miRNAs changed their dominate form between 5' and 3' strands in different cancer types, including miR-486, miR-99b, let-7e, miR-125a, let-7g, miR-339, miR-26a, miR-16, and miR-218, whereas only two miRNAs with multiple host genes switched their co-transcriptional partner in different cancer types (miR-219a-1 with SLC39A7/HSD17B8 and miR-3615 with RAB37/SLC9A3R1). miRNAs generated from distinct precursors (such as miR-125b from miR-125b-1 or miR-125b-2) were more likely to have cancer-dependent main contributors. miRNAs and hosts were less co-expressed in KIRC than other cancer types, possibly due to its frequent VHL mutations. Our findings shed new light on miRNA biogenesis and cancer diagnosis and treatments.