Glioma cell proliferation is inhibited by miR-342-3p, miR-377 / E2F1 signaling pathway

Inhibitory effect of miR-377 on the proliferative and invasive behaviors of prostate cancer cells through the modulation of MYC mRNA via its interaction with BCL-2/Bax, PTEN, and CDK4

The MYC gene is a regulatory and proto-oncogenic gene that is overexpressed in the majority of prostate cancers (PCa). Numerous studies have indicated that aberrant expression of microRNAs is involved in the initiation and progression of prostate cancer. In this investigation, we assessed the impact of miR-377 on MYC through luciferase assay. Real-time PCR was employed to determine whether miR-377 could reduce the levels of MYC mRNA in transfected PCa cell lines (PC-3 and DU145) and change in the mRNA levels of BCL-2/Bax, PTEN, and CDK4 as a consequence of MYC downregulation. Moreover, we analyzed the effects of miR-377 on apoptosis, proliferation, cell cycle, and wound healing. Our findings demonstrate that miR-377 effectively targets MYC mRNA, as confirmed by luciferase assay and Real-time PCR. We observed a significant reduction in BCL-2 and CDK4 expression, along with an increase in Bax and PTEN, in prostate cancer cell lines upon MYC suppression. Additionally, elevated levels of miR-377 in PCa cell lines induced apoptosis, inhibited proliferation and migration, and arrested the cell cycle. Taken together, these results unveil the inhibitory role of miR-377 in MYC function within PCa, thereby suggesting its potential as a therapeutic target for the treatment of this malignancy.

MicroRNA-377: A therapeutic and diagnostic tumor marker

Cancer is considered as one of the main causes of human deaths globally. Despite the recent progresses in therapeutic modalities, there is still a high rate of mortality among cancer patients. Late diagnosis in advanced tumor stages is one of the main reasons for treatment failure in cancer patients. Therefore, it is required to suggest the novel strategies for the early tumor detection. MicroRNAs (miRNAs) have critical roles in neoplastic transformation by regulation of cell proliferation, migration, and apoptosis. They are always considered as non-invasive markers due to their high stability in body fluids. Since, all of the miRNAs have tissue-specific functions in different tumors as tumor suppressor or oncogene; it is required to investigate the molecular mechanisms of every miRNA in different tumors to introduce that as a suitable non-invasive diagnostic marker in cancer patients. For the first time in the present review, we discussed the role of miR-377 during tumor progression. It has been reported that miR-377 mainly functions as a tumor suppressor through the regulation of signaling pathways and transcription factors. This review is an important step toward introducing the miR-377 as a novel diagnostic marker as well as a therapeutic target in cancer patients.

ceRNA network of lncRNA MIR210HG/miR-377-3p/LMX1A in malignant proliferation of glioma cells

BACKGROUND

Glioma represents the most heterogeneous and malignant form of brain tumor with a poor prognosis. The long non-coding RNA (LncRNA)-mediated competing endogenous RNA (ceRNA) network plays a regulatory role in cancer progression.

OBJECTIVES

The present study was conducted to expound on the role of lncRNA MIR210 host gene (MIR210HG)-mediated ceRNA mechanism in the malignant proliferation of glioma cells and provide a novel theoretical basis for the treatment of glioma.

METHODS

Expression levels of lncRNA MIR210HG, microRNA (miR)-377-3p, and LIM homeobox transcription factor 1 alpha (LMX1A) in glioma tissues and cells were determined by reverse-transcription quantitative polymerase chain reaction. Then, cell proliferation was assessed by cell counting kit-8 and colony formation assays. After that, the subcellular localization of lncRNA MIR210HG was analyzed by subcellular fractionation assay and the bindings of miR-377-3p to lncRNA MIR210HG and LMX1A were analyzed by the dual-luciferase assay. Glioma cells were transfected with si-MIR210HG, miR-377-3p inhibitor, or overexpressed-LMX1A vectors to evaluate their effects on the malignant proliferation of glioma cells.

RESULTS

LncRNA MIR210HG was elevated in glioma tissues and cells and inhibition of lncRNA MIR210HG reduced the proliferation potential of glioma cells. LncRNA MIR210HG targeted and inhibited miR-377-3p and miR-377-3p targeted and inhibited LMX1A transcription. miR-377-3p downregulation or LMX1A overexpression reversed the inhibition of silencing lncRNA MIR210HG on glioma cell proliferation.

CONCLUSION

LncRNA MIR210HG was upregulated in glioma tissues and cells and inhibition of lncRNA MIR210HG suppressed glioma cell proliferation through promoting miR-377-3p and repressing LMX1A.

E2F transcription factor 1 elevates cyclin D1 expression by suppressing transcription of microRNA-107 to augment progression of glioma

BACKGROUND

Dysregulation of microRNAs has been frequently implicated in the progression of human diseases, including glioma. This study aims to explore the interaction between E2F transcription factor 1 (E2F1) and miR-107 in the progression of glioma.

METHODS

Expression of miR-107 in glioma tissues and cells was examined. Putative binding sites between E2F1 and the promoter region of miR-107, and between miR-107 and cyclin D1 (CCND1) mRNA were predicted via bioinformatic systems and validated via chromatin immunoprecipitation and luciferase reporter gene assays. Altered expression of miR-107, E2F1, and CCND1 was introduced in A172 and T98G cells to examine their roles in cell growth and the activity of the Wnt/β-catenin signaling. In vivo experiments were performed by injecting cells in nude mice.

RESULTS

miR-107 was poorly expressed, whereas E2F1 and CCND1 were highly expressed in glioma tissues and cells. E2F1 bound to the promoter region of miR-107 to induce transcriptional repression, and miR-107 directly bound to CCND1 mRNA to reduce its expression. Overexpression of miR-107 reduced proliferation, migration and invasion, and augmented apoptosis of glioma cells, and it reduced activity of the Wnt/β-catenin pathway. The anti-tumorigenic roles of miR-107 were blocked by E2F1 or CCND1 overexpression. Similar results were reproduced in vivo where miR-107 overexpression or E2F1 inhibition blocked tumor growth in nude mice.

CONCLUSION

This study suggested that E2F1 reduces miR-107 transcription to induce CCND1 upregulation, which leads to progression of glioma via Wnt/β-catenin signaling activation.

An Update on the Potential Roles of E2F Family Members in Colorectal Cancer

Colorectal cancer (CRC) is a major health burden worldwide, and thus, optimised diagnosis and treatments are imperative. E2F transcription factors (E2Fs) are a family of transcription factors consisting of eight genes, contributing to the oncogenesis and development of CRC. Importantly, E2Fs control not only the cell cycle but also apoptosis, senescence, DNA damage response, and drug resistance by interacting with multiple signaling pathways. However, the specific functions and intricate machinery of these eight E2Fs in human CRC remain unclear in many respects. Evidence on E2Fs and CRC has been scattered on the related regulatory genes, microRNAs (miRNAs), and competing endogenous RNAs (ceRNAs). Accordingly, some drugs targeting E2Fs have been transferred from preclinical to clinical application. Herein, we have systemically reviewed the current literature on the roles of various E2Fs in CRC with the purpose of providing possible clinical implications for patient diagnosis and prognosis and future treatment strategy design, thereby furthering the understanding of the E2Fs.

Double-targeting CDCA8 and E2F1 inhibits the growth and migration of malignant glioma

High-grade glioma is the most common and aggressive primary brain tumor in adults with poor therapeutic efficiency and survival prognosis. Cell division cycle associated 8 (CDCA8) has been well known as a cell cycle regulator and tumor promotor in various malignant tumors. However, its biological role in glioma still remains unclear. Our results showed that high level of CDCA8 was significantly correlated with advanced WHO grade and poor overall survival and disease-free survival prognosis. In vitro and in vivo investigations demonstrated that CDCA8 promoted the glioma malignancy by promoting cell proliferation, cell migration, and inhibiting cell apoptosis. Moreover, we found its synergetic biological protein-E2F1 by the gene microarray chip. In this study, we revealed that CDCA8 synergized with E2F1 facilitated the proliferation and migration of glioma. In conclusion, our study provides a novel promising therapeutic targets and prognostic biomarkers for malignant glioma treatment.

Expression, Prognosis, and Immune Infiltrates Analyses of E2Fs in Human Brain and CNS Cancer

Objective

We investigated the expression patterns, potential functions, unique prognostic value, and potential therapeutic targets of E2Fs in brain and CNS cancer and tumor-infiltrating immune cell microenvironments.

Methods

We analyzed E2F mRNA expression levels in diverse cancer types via Oncomine and GEPIA databases, respectively. Moreover, we evaluated the prognostic values using GEPIA database and TCGAportal database and the correlation of E2F expression with immune infiltration and the correlation between immune cell infiltration and GBM and LGG prognosis via TIMER database. Then, cBioPortal, GeneMANIA, and DAVID databases were used for mutation analysis, PPI network analysis of coexpressed gene, and functional enrichment analysis.

Results

E2F1-8 expression increased in most cancers, including brain and CNS cancer. Higher expression in E2F1, 2, 4, 6, 7, and 8 indicated poor OS of LGG. Higher E2F3–6 and E2F1–8 expressions correlated with poor prognosis and increased immune infiltration levels in CD8+ T cells, macrophages, neutrophils, and DCs in GBM and CD8+ T cells, B cells, CD4+ T cells, neutrophils, macrophages, and DCs in LGG, respectively.

Conclusion

E2F1–8 and E2F2–8 could be hopeful prognostic biomarkers of GBM and LGG, respectively. E2F3–6 and E2F1–8 could be likely therapeutic targets in patients with immune cell infiltration of GBM and LGG, respectively.

LncRNA H19 Promotes Cell Proliferation, Migration, and Angiogenesis of Glioma by Regulating Wnt5a/β-Catenin Pathway via Targeting miR-342

Glioma is the most common malignant brain tumor and long non-coding RNAs (lncRNAs) have been reported to play an important role in the growth and angiogenesis of glioma. However, the potential mechanisms of lncRNA H19 in glioma remain unclear. In the present study, the effects of lncRNA H19 on glioma cell proliferation, migration, and angiogenesis were evaluated. The expression levels of H19, miR-342, and Wnt5a in glioma tissues and cells were detected by RT-qPCR or Western blotting. Dual luciferase reporter assay confirmed the interaction between H19, miR-342, and Wnt5a. Cell proliferation, migration, and angiogenesis were analyzed by colony formation, transwell, and tube formation assays, respectively. IHC was performed to test the angiogenesis-related factor CD31. H19 and Wnt5a expression were remarkably upregulated in glioma tissues and cells, whereas miR-342 expression was downregulated. Moreover, functional analysis confirmed that knockdown of H19 or overexpression of miR-342 suppressed glioma cell proliferation, migration, and angiogenesis in vitro. Besides, H19 was found to directly target miR-342 to promote Wnt5a expression and activate β-catenin pathway in glioma cells. Moreover, suppression of miR-342 or overexpression of Wnt5a reversed the inhibitory effect of sh-H19 on glioma growth and metastasis. Additionally, we verified that H19 promoted glioma cell proliferation, migration, and angiogenesis via miR-342/Wnt5a/β-catenin axis in vivo. H19 regulates glioma cell growth and metastasis through miR-342 to mediate Wnt5a/β-catenin signaling pathway, which provides new therapeutic targets for glioma treatment.

[Advancement of E2F1 in Common Tumors]

细胞周期相关转录因子E2F1（E2F transcription factor 1）是细胞周期相关转录因子E2F家族成员之一，主要参与包括细胞周期进展、DNA修复、DNA复制、细胞分化，增殖和凋亡等多种细胞过程。E2F1在全身多种肿瘤组织和细胞中呈高表达，起着促癌基因的作用，E2F1表达上调与肿瘤的发生、发展、转移及预后密切相关。因此，E2F1有望成为肿瘤治疗的新靶点。本文就E2F1在目前常见肿瘤中的最新研究进展做一综述。

Analysis of Postdeployment Serum Samples Identifies Potential Biomarkers of Exposure to Burn Pits and Other Environmental Hazards

OBJECTIVE

The potential health risks of deployment to sites with open burn pits remain poorly understood, in part, because personal exposure monitoring was not performed. Here, we investigated whether postdeployment serum samples contain biomarkers associated with exposure to burn pits.

METHODS

A total of 237 biomarkers were measured in 800 serum samples from deployed and never-deployed subjects. We used a regression model and a supervised vector machine to identify serum biomarkers with significant associations with exposures and deployment.

RESULTS

We identified 101 serum biomarkers associated with polycyclic aromatic hydrocarbons, dioxins or furans, and 54 biomarkers associated with deployment. Twenty-six of these biomarkers were shared in common by the exposure and deployment groups.

CONCLUSIONS

We identify a potential signature of exposure to open burn pits, and provide a framework for using postexposure sera to identify exposures when contemporaneous monitoring was inadequate.

MiR-342 attenuates lipopolysaccharide-induced acute lung injury via inhibiting MAPK1 expression

Micro RNA (miRNA) and mitogen-activated protein kinase (MAPK) are reported as the crucial regulators of inflammatory responses in acute lung injury (ALI). This study will explore the role of the miR-342/MAPK1 axis in regulation of lipopolysaccharide (LPS)-induced ALI. We found that miR-342 was down-regulated in LPS-induced A549 cells compared with the control group with DMSO, accompanied by elevated inflammatory cytokines and apoptosis. Over-expression of miR-342 reduced LPS-induced inflammatory responses and apoptosis in LPS-stimulated A549 cells, and had a protective role in LPS-treated mice with ALI by decreasing levels of inflammatory cytokines, improving survival of mice with ALI, and ameliorating the lung permeability. Dual-luciferase reporter gene assay demonstrated that miR-342 regulated the expression of MAPK1 by directly targeting its 3' untranslated region (3'-UTR). Mechanistically, MAPK1 silencing abrogated LPS-induced inflammatory injury in A549 cells, and partially enhanced the protective effect of miR-342. Therefore, miR-342 attenuates LPS-induced ALI by targeting MAPK1 expression, thereby protecting against A549 cell injury induced by LPS and lung injury of mice with ALI.