Low microRNA-622 expression predicts poor prognosis and is associated with ZEB2 in glioma

Zinc Finger E-Box Binding Homeobox Family: Non-Coding RNA and Epigenetic Regulation in Gliomas

Gliomas are the most common malignant brain tumours. Among them, glioblastoma (GBM) is a grade four tumour with a median survival of approximately 15 months and still limited treatment options. Although a classical epithelial to mesenchymal transition (EMT) is not the case in glioma due to its non-epithelial origin, the EMT-like processes may contribute largely to the aggressive and highly infiltrative nature of these tumours, thus promoting invasive phenotype and intracranial metastasis. To date, many well-known EMT transcription factors (EMT-TFs) have been described with clear, biological functions in glioma progression. Among them, EMT-related families of molecules such as SNAI, TWIST and ZEB are widely cited, well-established oncogenes considering both epithelial and non-epithelial tumours. In this review, we aimed to summarise the current knowledge with a regard to functional experiments considering the impact of miRNA and lncRNA as well as other epigenetic modifications, with a main focus on ZEB1 and ZEB2 in gliomas. Although we explored various molecular interactions and pathophysiological processes, such as cancer stem cell phenotype, hypoxia-induced EMT, tumour microenvironment and TMZ-resistant tumour cells, there is still a pressing need to elucidate the molecular mechanisms by which EMT-TFs are regulated in gliomas, which will enable researchers to uncover novel therapeutic targets as well as improve patients' diagnosis and prognostication.

Propofol inhibits glioma progression by regulating circMAPK4/miR-622/HOXA9 axis

Propofol has a tumor-suppressive role in glioma, but the mechanism by which propofol is involved in glioma progression is largely unknown. This study aims to explore a potential circular RNAs (circRNAs)/microRNAs (miRNAs)/mRNA network in response to Propofol in glioma. Human glioma cell lines (U251 and LN229) were suffered from Propofol treatment (5 μg/mL for 24 h) and transfection. circRNA mitogen-activated protein kinase 4 (circMAPK4), miR-622, homeobox A9 (HOXA9) abundances were determined by quantitative reverse transcription polymerase chain reaction and western blot. Migration and invasion were analyzed via transwell analysis. Cell proliferation was evaluated using Cell Counting Kit-8 and colony formation analysis. Cell apoptosis and related protein expression were determined via flow cytometry and western blot. Target relationship was assessed via dual-luciferase reporter analysis, RNA pull-down and RNA immunoprecipitation. Propofol reduced circMAPK4 expression. Propofol inhibited cell proliferation, migration and invasion, while increased apoptosis via decreasing circMAPK4 in glioma cells. miR-622 was targeted via circMAPK4. circMAPK4 knockdown decreased glioma cell growth, migration and invasion by up-regulating miR-622. miR-622 knockdown reversed the effect of Propofol on glioma progression. HOXA9 was targeted by miR-622, and its expression was decreased by Propofol treatment. miR-622 overexpression restrained glioma progression via decreasing HOXA9. Propofol regulated circMAPK4/miR-622/HOXA9 axis in glioma cells. Propofol constrains glioma progression by regulating circMAPK4/miR-622/HOXA9 axis in vitro. Propofol restrains glioma cell growth, migration and invasion. circMAPK4 can regulate HOXA9 by sponging miR-622 in glioma cells. Propofol represses glioma progression via a circMAPK4/miR-622/HOXA9 axis.

A Novel-Defined Necroptosis-Related miRNA Signature for Forecasting the Prognosis of Low-Grade Glioma

Background

Increasing evidence has shown that necroptosis has enormous significance in the generation and deterioration of cancer, and miRNA molecular markers involved in necroptosis in low-grade gliomas (LGGs) have not been thoroughly reported.

Methods

Using the miRNA data of 512 samples from The Cancer Genome Atlas (TCGA), 689 miRNAs from LGG samples were split into high immunity score and low immunity score groups for analysis. The differential miRNAs related to necroptosis were analyzed by univariate Cox regression analysis. On the basis of the outcome of univariate Cox regression analysis, miRNAs with significant differences were selected to construct a multivariate Cox regression model and calculate the risk score. Then, we evaluated whether the risk score could be used as an unaided prognostic factor.

Results

Overall, six differential miRNAs were identified (hsa-miR-148a-3p, hsa-miR-141-3p, hsa-miR-223-3p, hsa-miR-7-5p, hsa-miR-500a-3p, and hsa-miR-200a-5p). Univariate and multivariate Cox regression analyses were performed, and the c index was 0.71. Then, by mixing the risk score with clinicopathological factors, univariate Cox regression (HR: 2.7146, 95% CI: 1.8402−4.0044, P < 0.0001) and multivariate Cox regression analyses (HR: 2.3280, 95% CI: 1.5692−3.4536, P < 0.001) were performed. The data suggested that the risk score is an unaided prognostic indicator, which is markedly related with the overall survival time of LGG sufferers. Thus, a lower risk score is correlated with better prediction of LGG.

Conclusion

In order to achieve the ultimate goal of improving the living conditions of patients, we established prognostic risk model using 6 miRNAs related to necroptosis, which has the ability to predict the prognosis of LGG. It is possible to further enrich the therapeutic targets for LGG and provide clinical guidance for the treatment of LGG in the future.

miR-622 Counteracts the NUAK1-Induced Gastric Cancer Cell Proliferation and the Antioxidative Stress

Background

Gastric cancer (GC), a highly prevalent gastric cancer, has high-risk mortality. Thus, investigating strategies to counteract its growth is important to provide theoretical guidance for its prevention and treatment. It has been pointed out that abnormal expression of microRNAs (miRNAs) serves as noninvasive biomarkers for GC. This present study probed into the role of miR-622 and the NUAK family SNF1-like kinase 1 (NUAK1).

Methods

Five mRNA datasets (GSE64916, GSE118916, GSE122401, GSE158662, and GSE159721) and one miRNA dataset (GSE128720) from the Gene Expression of Omnibus (GEO) database were used to analyze the differentially expressed miRNAs and mRNA in GC and noncancer samples. Further, western blot, real-time quantitative PCR (qRT-PCR), reactive oxygen species (ROS) assay kit experiments, and wound healing assay, together with in vivo experiments, were performed.

Results

miR-622 was downregulated, and NUAK1 was upregulated in GC, and NUAK1 was a potential target of miR-622. Knocking down NUAK1 decreased GC cell proliferation and migration but increased oxidative stress in vitro and inhibited the development of tumor in vivo, while miR-622 acted to suppress the action of NUAK1 through the miR-622/NUAK1/p-protein kinase B (Akt) axis, thereby inhibiting the occurrence of GC.

Conclusion

miR-622 and NUAK1 demonstrated potential for being targets and biomarkers for GC treatment.

The expression and function of miR-622 in a variety of tumors

Cancer is a heavy burden worldwide, with high morbidity and mortality rates. Cancer treatments currently involve surgical and nonsurgical approaches. Molecular targeted therapy is the latest breakthrough. miRNAs are small noncoding RNAs found in plants and animals that play a role in cancer and various diseases through influencing numerous biological processes, such as cell proliferation, apoptosis, the immune response, and drug resistance. One miRNA, miR-622, has been shown to regulate various pathways to influence disease processes. Abnormal miR-622 expression can promote or inhibit liver, colorectal, and breast cancers and other tumors, such as glioma. Herein, we reviewed the expression levels and clinical effects of miR-622 in various tumors and summarized its mechanisms and related molecules.

MiR-622 acts as a tumor suppressor to induce cell apoptosis and inhibit metastasis in human prostate cancer

Growing evidence indicating the critical modulator roles of microRNAs (miRNAs) involved in prostate cancer (PCa) metastasis that holds great promise as therapeutic targets. Herein, we transfected the miR-622 mimic into PC3 cells and evaluated the effects of this interference on these tumour cells' growth and the expression of specific metastatic genes. Transfecting of miR-622 mimic and inhibitor, negative control (NC) inhibitor and NC was established using Lipofectamine 2000. The mRNA levels of miR-622 and metastatic genes were evaluated using the qRT-PCR and Western blot. Cytotoxic effects of miR-622 were assessed by MTT. Apoptosis was detected using an ELISA cell death assay kit. miR-622 is down-regulated in PC3 cells. As expected, cell viability effects after transfection were described as miR-622 inhibitor >NC and NC inhibitor >miR-622 mimic (p < .01). Importantly, we showed that transfected miR-622 mimic could enhance the apoptosis of PC3 cells, while transfected miR-622 inhibitor could decrease cell apoptosis (p < .01). Furthermore, miR-622 overexpression could increase significantly down-regulated the MMP2, MMP9, CXCR-4, c-Myc and K-Ras expression levels. Findings demonstrate a novel mechanism by which miR-622 modulates PCa cells' metastasis by targeting metastatic genes. These data confirm the tumour-suppressive function of miR-622 in PCa cells by enhancing apoptosis and reducing metastasis.

ZEB2 facilitates peritoneal metastasis by regulating the invasiveness and tumorigenesis of cancer stem-like cells in high-grade serous ovarian cancers

Peritoneal metastasis is a common issue in the progression of high-grade serous ovarian cancers (HGSOCs), yet the underlying mechanism remains unconfirmed. We demonstrated that ZEB2, the transcription factor of epithelial–mesenchymal transition (EMT), was upregulated in ascites cells from HGSOC patients and in CD133⁺ cancer stem-like cells (CSLCs) from epithelial ovarian cancer (EOC) cell lines. SiRNA-mediated knockdown of ZEB2 in EOC cells decreased the percentage of CSLCs and reduced the colony forming potential, cell invasion capacity and expression of pluripotent genes Oct4 and Nanog. Inhibition of ZEB2 also induced cellular apoptosis and impacted the tumorigenicity of ovarian CSLCs. The mesenchymal markers N-cadherin and vimentin were downregulated, while the epithelial marker E-cadherin was upregulated after ZEB2 knockdown. MiR-200a, a molecule that downregulates ZEB2, had the opposite effect of ZEB2 expression in EOC-CSLCs. A retrospective study of 98 HGSOC patients on the relationship of ascites volume, pelvic and abdominal metastasis, International Federation of Gynecology and Obstetrics (FIGO) stage and the malignant involvement of abdominal organs and lymph nodes was performed. Patients with high expression of ZEB2 in tumour tissues had a higher metastasis rate and a poorer prognosis than those with low expression. The parameters of ZEB2 expression and ascites volume were strongly linked with the prognostic outcome of HGSOC patients and had higher hazard ratios. These findings illustrated that ZEB2 facilitates the invasive metastasis of EOC-CSLCs and can predict peritoneal metastasis and a poor prognosis in HGSOC patients.

Long noncoding RNA LIFR-AS1 suppresses proliferation, migration and invasion and promotes apoptosis through modulating miR-4262/NF-κB pathway in glioma

AIM

This study aimed to explore the role of lncRNA leukemia inhibitory factor receptor antisense RNA 1 (LIFR-AS1) on glioma and its underlying molecular mechanism.

METHODS

The expression of LIFR-AS1 and miR-4262 was detected by quantitative real-time polymerase chain reaction (qRT-RCR) in both glioma tissues and cell lines. Colony formation assay, 5-ethynyl-20-deoxyuridine (EdU) assay, flow cytometry and transwell assay were respectively conducted to detect cell clones, proliferation, apoptosis, migration and invasion. The effect of LIFR-AS1 on the chemoresistance to temozolomide (TMZ) of glioma cells was also analyzed. In addition, dual-luciferase reporter gene assay was performed to evaluate the luciferase activity. The expressions of nuclear factor-κB (NF-κB) p65, p-NF-κB p65 and inhibitor of κBα (IκBα) in glioma cells were measured by western blot.

RESULTS

LIFR-AS1 was lowly expressed and miR-4262 was highly expressed in glioma tissues and cell lines. LIFR-AS1 overexpression inhibited the proliferation, migration and invasion and promoted apoptosis of glioma cells. LIFR-AS1 overexpression also reduced the chemoresistance to TMZ of glioma cells. Moreover, LIFR-AS1 overexpression suppressed the activation of NF-κB signaling pathway in glioma cells. miR-4262 was the target gene of LIFR-AS1. We also found that miR-4262 abrogated the functions of LIFR-AS1 on cell proliferation, apoptosis, migration and invasion of glioma cells in the NF-κB pathway.

CONCLUSION

LIFR-AS1 could suppress the proliferation, migration and invasion and promote the apoptosis through modulating miR-4262/NF-κB pathway in glioma.

MiR-874 Inhibits Cell Proliferation, Migration, and Invasion of Glioma Cells and Correlates with Prognosis of Glioma Patients

Previous studies showed that miR-874 expression was abnormally expressed in many tumors. However, the potential role of miR-874 in glioma remains a mystery. This study aimed to investigate its expression, clinical significance, and cellular function in glioma. A total of 105 glioma patients were enrolled in the present study. The RT-qPCR analysis was used to detect the expression of miR-874 in glioma tissues and cells. The χ² test was used to analyze the association between miR-874 expression and clinical characteristics of patients. Kaplan-Meier method and multivariate Cox regression assays were used to analyze the prognostic value of miR-874 in glioma. Cell counting kit-8 and Transwell assays were used to explore the alterations in a series of cancer-related phenotypes affected by miR-874, including cell proliferation, migration, and invasion capacities. The expression of miR-874 was significantly downregulated in human glioma tissue specimens and cell lines. Furthermore, the expression of miR-874 was associated with tumor size, KPS, and WHO grade. The decreased expression of miR-874 was associated with shorter overall survival. Then functional assays indicated that upregulation of miR-874 suppressed proliferation, migration, and invasion of glioma cells in vitro. The present study indicated that miR-874 inhibited cell proliferation, migration, and invasion of glioma cells and might be a novel prognostic biomarker and potential therapeutic target for glioma.

MicroRNA-136-3p inhibits glioma tumorigenesis in vitro and in vivo by targeting KLF7

Background

Malignant brain tumors have been a serious threat to human health worldwide. This study aims to investigate the role of miR-136-3p in glioma development.

Methods

Hematoxylin-eosin staining (H&E) staining was used to determine the pathologic alterations of glioma tissues. Quantitative real-time PCR (qRT-PCR) analysis and GEO2R analysis was performed to examine the expression of miRNAs and genes. Western blot was applied to detect the protein expression. Cell counting kit-8 (CCK-8) and colony formation were used to analyze the glioma cell growth. Trans-well assay was used to determine the cell migration. Annexin V-FITC/PI staining was conducted to determine the cell apoptosis of transfected glioma cells. The dual-luciferase reporter assay was carried out to confirm the binding sites of miR-136-3p on 3′ untranslated regions (3′ UTR) of Kruppel-like factor 7 (KLF7). Tumor-bearing experiment in nude mice was performed to comprehensively investigate the role of miR-136-3p/KLF7 axis in gliomas.

Results

Firstly, the results showed that miR-136-3p was decreased in glioma tissues compared with adjacent tissues. Overexpression of miR-136-3p significantly inhibited cell growth of LN-229 and U251 by decreasing expression of Cyclin A1 and PCNA (proliferating cell nuclear antigen), and it suppressed glioma cell migration by downregulating N-cadherin and elevating E-cadherin levels, and it also promotes glioma cell apoptosis by promoting Bcl2-associated X (Bax) expression but suppressing Bcl-2 expression. Furthermore, we observed that KLF7 was a direct target of miR-136-3p, and KLF7 was negatively regulated by miR-136-3p in glioma cells. Finally, overexpression of KLF7 partly blocked miR-136-3p-induced inhibition of tumor growth in vitro and in vivo.

Conclusions

Targeting miR-136-3p/KLF7 axis might be a novel manner to counter against gliomas.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.

miR-6869-5p Inhibits Glioma Cell Proliferation and Invasion via Targeting PGK1

Accumulating studies have suggested the dysregulated microRNAs (miRNAs) play important roles in brain tumors, including glioma. miR-6869-5p has been documented to be aberrantly expressed in diverse cancers. However, the precise role of miR-6869-5p in glioma remains poorly understood. This study is aimed at evaluating its modifying effects on glioma. Significantly decreased expression of miR-6869-5p was found in glioma tissues and cells. Negative association was documented between miR-6869-5p and PGK1 in glioma cells, and PGK1 was demonstrated to be a targeted gene of this miRNA by luciferase reporter assay. miR-6869-5p regulated glioma cell proliferation and invasion via targeting PGK1. In addition, the survival analysis had suggested that low miR-6869-5p expression predicted poor prognosis of glioma patients. This study has suggested that miR-6869-5p is a useful tumor suppressor and prognostic marker in glioma.