MicroRNA-566 activates EGFR signaling and its inhibition sensitizes glioblastoma cells to nimotuzumab

Exploring ncRNA-mediated regulation of EGFR signalling in glioblastoma: From mechanisms to therapeutics

Glioblastoma (GBM) is the most prevalent and deadly primary brain tumor type, with a discouragingly low survival rate and few effective treatments. An important function of the EGFR signalling pathway in the development of GBM is to affect tumor proliferation, persistence, and treatment resistance. Advances in molecular biology in the last several years have shown how important ncRNAs are for controlling a wide range of biological activities, including cancer progression and development. NcRNAs have become important post-transcriptional regulators of gene expression, and they may affect the EGFR pathway by either directly targeting EGFR or by modifying important transcription factors and downstream signalling molecules. The EGFR pathway is aberrantly activated in response to the dysregulation of certain ncRNAs, which has been linked to GBM carcinogenesis, treatment resistance, and unfavourable patient outcomes. We review the literature on miRNAs, circRNAs and lncRNAs that are implicated in the regulation of EGFR signalling in GBM, discussing their mechanisms of action, interactions with the signalling pathway, and implications for GBM therapy. Furthermore, we explore the potential of ncRNA-based strategies to overcome resistance to EGFR-targeted therapies, including the use of ncRNA mimics or inhibitors to modulate the activity of key regulators within the pathway.

Functions of non-coding RNAs in regulating cancer drug targets

With the development of precision medicine, the efficiency of tumor treatment has been significantly improved. More attention has been paid to targeted therapy and immunotherapy as the key to precision treatment of cancer. Targeting epidermal growth factor receptor (EGFR) has become one of the most important targeted treatments for various cancers. Comparing with traditional chemotherapy drugs, targeting EGFR is highly selective in killing tumor cells with better safety, tolerability and less side effect. In addition, tumor immunotherapy has become the fourth largest tumor therapy after surgery, radiotherapy and chemotherapy, especially immune checkpoint inhibitors. However, these treatments still produce a certain degree of drug resistance. Non-coding RNAs (ncRNAs) were found to play a key role in carcinogenesis, treatment and regulation of the efficacy of anticancer drugs in the past few years. Therefore, in this review, we aim to summarize the targeted treatment of cancers and the functions of ncRNAs in cancer treatment.

A Novel Urinary miRNA Biomarker for Early Detection of Colorectal Cancer

Simple Summary

Early diagnosis is critically important to achieve life-saving therapy for colorectal cancer (CRC). Since colonoscopy is not suitable as a screening method for CRC due to its invasiveness and high-cost, reliable and non-invasive diagnostic biomarkers are hopeful for CRC. In this case-control study, we established completely non-invasive, novel urinary microRNA (miRNA) biomarker panel combining miR-129-1-3p and miR-566 for the diagnosis of CRC. In the independent age- and sex-matched three cohorts comprising 415 participants, urinary levels of these miRNAs were consistently elevated in the CRC group compared to the healthy controls. Notably, the panel of combining miR-129-1-3p and miR-566 revealed an AUC of 0.845 for stage 0/I CRC that can be treated with endoscopic resection.

Abstract

Since noninvasive biomarkers as an alternative to invasive colonoscopy to detect colorectal cancer (CRC) are desired, we conducted this study to determine the urinary biomarker consisting of microRNAs (miRNAs). In total, 415 age- and sex-matched participants, including 206 patients with CRC and 209 healthy controls (HCs), were randomly divided into three groups: (1) the discovery cohort (CRC, n = 3; HC, n = 6); (2) the training cohort (140 pairs); and (3) the validation cohort (63 pairs). Among 11 urinary miRNAs with aberrant expressions between the two groups, miR-129-1-3p and miR-566 were significantly independent biomarkers that detect CRC. The panel consisting of two miRNAs could distinguish patients with CRC from HC participants with an area under the curve (AUC) = 0.811 in the training cohort. This panel showed good efficacy with an AUC = 0.868 in the validation cohort. This urinary biomarker combining miR-129-1-3p and miR-566 could detect even stage 0/I CRC effectively with an AUC = 0.845. Moreover, the expression levels of both miR-129-1-3p and miR-566 were significantly higher in primary tumor tissues than in adjacent normal tissue. Our established novel biomarker consisting of urinary miR-129-1-3p and miR-566 enables noninvasive and early detection of CRC.

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.

MicroRNAs involved in the EGFR pathway in glioblastoma

Glioblastoma (GBM) is the most common primary malignant tumor in adults, and its morbidity and mortality are very high. Although progress has been achieved in the treatment of GBM, such as surgery, chemotherapy and radiotherapy, in recent years, the prognosis of patients with GBM has not improved significantly. MicroRNAs (miRNAs) are endogenous noncoding single-stranded RNAs consisting of approximately 20-22 nucleotides that regulate gene expression at the posttranscriptional level by binding to target protein-encoding mRNAs. Notably, miRNAs regulate various carcinogenic pathways, one of which is the epidermal growth factor receptor (EGFR) signaling pathway, which controls cell proliferation, invasion, migration, angiogenesis and apoptosis. In this review, we summarize the novel discoveries of roles for miRNAs targeting the factors in the EGFR signaling pathway in the occurrence and development of GBM. In addition, we describe their potential roles as biomarkers for the diagnosis and prognosis of GBM and for determining the treatment resistance of GBM and the efficacy of therapeutic drugs.

Targeting the Ubiquitin System in Glioblastoma

Glioblastoma is the most common primary brain tumor in adults with poor overall outcome and 5-year survival of less than 5%. Treatment has not changed much in the last decade or so, with surgical resection and radio/chemotherapy being the main options. Glioblastoma is highly heterogeneous and frequently becomes treatment-resistant due to the ability of glioblastoma cells to adopt stem cell states facilitating tumor recurrence. Therefore, there is an urgent need for novel therapeutic strategies. The ubiquitin system, in particular E3 ubiquitin ligases and deubiquitinating enzymes, have emerged as a promising source of novel drug targets. In addition to conventional small molecule drug discovery approaches aimed at modulating enzyme activity, several new and exciting strategies are also being explored. Among these, PROteolysis TArgeting Chimeras (PROTACs) aim to harness the endogenous protein turnover machinery to direct therapeutically relevant targets, including previously considered "undruggable" ones, for proteasomal degradation. PROTAC and other strategies targeting the ubiquitin proteasome system offer new therapeutic avenues which will expand the drug development toolboxes for glioblastoma. This review will provide a comprehensive overview of E3 ubiquitin ligases and deubiquitinating enzymes in the context of glioblastoma and their involvement in core signaling pathways including EGFR, TGF-β, p53 and stemness-related pathways. Finally, we offer new insights into how these ubiquitin-dependent mechanisms could be exploited therapeutically for glioblastoma.

Proteomics identifies EGF-like domain multiple 7 as a potential therapeutic target for epidermal growth factor receptor-positive glioma

Background

Glioma, the most frequent primary tumor of the central nervous system, has poor prognosis. The epidermal growth factor receptor (EGFR) pathway and angiogenesis play important roles in glioma growth, invasion, and recurrence. The present study aimed to use proteomic methods to probe into the role of the EGF‐EGFR‐angiogenesis axis in the tumorigenesis of glioma and access the therapeutic efficacy of selumetinib on glioma.

Methods

Proteomic profiling was used to characterize 200 paired EGFR‐positive and EGFR‐negative glioma tissues of all pathological types. The quantitative mass spectrometry data were used for systematic analysis of the proteomic profiles of 10 EGFR‐positive and 10 EGFR‐negative glioma cases. Consensus‐clustering analysis was used to screen target proteins. Immunofluorescence analysis, cell growth assay, and intracranial xenograft experiments were used to verify and test the therapeutic effect of selumetinib on glioma.

Results

Advanced proteomic screening demonstrated that the expression of EGF‐like domain multiple 7 (EGFL7) was higher in EGFR‐positive tumor tissues than in EGFR‐negative tumor tissues. In addition, EGFL7 could act as an activator in vitro and in vivo to promote glioma cell proliferation. EGFL7 was associated strongly with EGFR and prognosis. EGFL7 knockdown effectively suppressed glioma cell proliferation. Selumetinib treatment showed tumor reduction effect in EGFR‐positive glioblastoma xenograft mouse model.

Conclusions

EGFL7 is a potential diagnostic biomarker and therapeutic target of glioma. Selumetinib could target the EGFR pathway and possibly improve the prognosis of EGFR‐positive glioma.

miR-566 expression and immune changes in patients with intracranial aneurysm

OBJECTIVE

Our study aims to investigate the correlations of micro ribonucleic acid (miR)-566 expression with the changes in immune-related indexes and differential genes in patients with intracranial aneurysm (IA).

METHODS

Aneurysm wall tissues from a total of 50 IA cases and the corresponding normal arterial wall tissues from 50 individuals were selected. The miR-566 expression, differential gene expression profile, and expression level of differential gene proteins were detected and analyzed by fluorescence quantitative polymerase chain reaction (qPCR), RNAseq technique and western blotting, respectively.

RESULTS

The miR-566 level was significantly higher in intracranial aneurysm tissues than that in normal arterial wall tissues (P<0.05). The levels of cluster of differentiation (CD)3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺ and CD23⁺ T lymphocytes in the peripheral blood of IA patients significantly declined compared with those in the control group (P<0.05). RNAseq detection showed that there were 16 immune-inflammation-related genes significantly differentially expressed in aneurysm wall tissues compared with normal arterial wall tissues in the control group. The levels of VHL and NIK in aneurysm wall tissues were significantly decreased, while those of VEGF and ALOX5 were obviously increased. Both mRNA and protein levels of these four genes also had significant changes, which had linear relations to the expression of miR-566.

CONCLUSION

The abnormal expression of miR-566 affects the immune function, thus promoting the occurrence and deterioration of intracranial aneurysm.

MiR-566 mediates cell migration and invasion in colon cancer cells by direct targeting of PSKH1

Background

Colorectal cancer (CRC), a common malignancy worldwide, and microRNAs (miRs) have been suggested to play roles in the disease. MiR-566 expression has been shown to be reduced in CRC, but its functions and mechanisms are still unclear.

Methods

Cell viability was assessed by using the CellTiter 96 AQueous One Solution Cell Proliferation kit. Cell proliferation was measured with MTT assay. Cell metastasis were measured by transwell assay. Luciferase reporter assays was used to confirm the target of MiR-566. PSKH1 expression was measured by RT-PCR and western blot.

Results

In the present study, we first observed that miR-566 was expressed in several CRC cell lines (SW480, SW620, LoVo, HT29 and Caco-2) at low levels compared to control colon epithelial cell lines (FHC). Further study showed that miR-566 overexpression suppressed cell survival and impeded cell proliferation, whereas inhibition of its expression enhanced cell survival and proliferation. Transwell assays showed that cell invasion and migration were reduced in cells overexpressing miR-566 and increased in those with inhibition of miR-566. Further analysis confirmed that PSKH1 is a target of miR-566. MiR-566 overexpression significantly inhibited PSKH1 expression and reintroduction of PSKH1 partially reversed the effects of miR-566 on CRC cell growth and metastasis in SW480 and Caco-2 cells.

Conclusions

Taken together, the data show that CRC cell growth and metastasis can be significantly suppressed by miR-566 through targeting PSKH1.

Tunneling Nanotubes Mediated microRNA-155 Intercellular Transportation Promotes Bladder Cancer Cells' Invasive and Proliferative Capacity

Objective

To investigate differential microRNAs' expression in heterogeneous bladder cancer cells, as well as to investigate the mechanism of changes in invasive and proliferative capacity induced by tunneling nanotubes (TNTs) mediated transport of microRNA between bladder cancer cells of varying histological grade.

Materials and methods

Differences in microRNA expression between bladder cancer cells of different grade were identified from a literature review. The identified heterogeneous microRNAs were analyzed by qPCR in T24 (high grade) and RT4 (low grade) bladder cancer cells. Scanning electron microscopy (SEM) and laser confocal fluorescence microscopy (LCM) were used to observe tunneling nanotubes (TNTs) between RT4 and T24 cells. Differentially expressed microRNA was labeled and traced by Fluorescent In Situ Hybridization (FISH) following co-culture of T24 and RT4 cells. MicroRNA mimic and inhibition technologies were applied to investigate how TNTs-mediated intercellular transport of microRNA affects the invasive and proliferative behavior of bladder cancer cells.

Results

MicroRNA-155 (miR-155) levels were highly expressed in T24 cells, whereas the same was not true in RT4 cells. MiR-155 was confirmed to be a crucial factor sustaining T24 bladder cancer cell proliferation, migration and cell cycle progression by CCK8, Matrigel test and cell cycle analysis, respectively. After T24 and RT4 co-culture, TNTs were assessed by SEM and LCM between T24 and RT4 cells. In addition, we observed TNTs mediated transport of miR-155 from T24 cells to RT4 cells, which thereby acquired a higher proliferative rate, an increased frequency of cells in the S phase, and increased invasive ability in Matrigel test. At the same time, Deptor, the target protein of miR-155 in RT4 cells, was downregulated, followed by mTOR/4EBP1/p70S6K- eIF4e/S6RP signaling activation.

Conclusion

MiR-155 was differentially expressed between RT4 and T24 bladder cancer cells. Intercellular transport of miR-155 via TNTs can promote bladder cancer cell reprogramming by Deptor-mTOR signal pathway activation.

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Insights into the Regulation of Tumor Angiogenesis by Micro-RNAs

One of the hallmarks of cancer is angiogenesis, a series of events leading to the formation of the abnormal vascular network required for tumor growth, development, progression, and metastasis. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNAs whose functions include modulation of the expression of pro- and anti-angiogenic factors and regulation of the function of vascular endothelial cells. Vascular-associated microRNAs can be either pro- or anti-angiogenic. In cancer, miRNA expression levels are deregulated and typically vary during tumor progression. Experimental data indicate that the tumor phenotype can be modified by targeting miRNA expression. Based on these observations, miRNAs may be promising targets for the development of novel anti-angiogenic therapies. This review discusses the role of various miRNAs and their targets in tumor angiogenesis, describes the strategies and challenges of miRNA-based anti-angiogenic therapies and explores the potential use of miRNAs as biomarkers for anti-angiogenic therapy response.

Overexpression of lncRNA PIK3CD-AS1 promotes expression of LATS1 by competitive binding with microRNA-566 to inhibit the growth, invasion and metastasis of hepatocellular carcinoma cells

Background

This study is conducted to investigate the effect of lncRNA PIK3CD-AS1 on the growth and metastasis of hepatocellular carcinoma (HCC) and its potential mechanism.

Methods

Hepatocellular carcinoma tissues and adjacent normal tissues together with HCC cells and normal liver cells were obtained for detecting expression of PIK3CD-AS1, microRNA-566 (miR-566) and LATS1. Additionally, a series of experiments were performed to determine cell proliferation, migration, invasion, cell cycle distribution and apoptosis of HCC cells. The xenograft tumor model of HCC was established and the growth rate and weight of xenograft tumor in nude mice were compared. Furthermore, the binding site between PIK3CD-AS1 and miR-566 as well as between miR-566 and LATS1 were verified.

Results

LncRNA PIK3CD-AS1 was downregulated in HCC tissues and cells, and mainly located in cytoplasm. Overexpression of PIK3CD-AS1 inhibited proliferation, colony formation, invasion, migration, epithelial–mesenchymal transition (EMT) and cell cycle progression and promoted apoptosis of HCC cells. Overexpression of PIK3CD-AS1 decreased the growth rate and weight of xenograft tumor in nude mice PIK3CD-AS1 competitively combined with miR-566 to regulate expression of LAST1.

Conclusion

Collectively, our study suggests that the expression of PIK3CD-AS1 was down-regulated in HCC, and overexpression of PIK3CD-AS1 promoted the expression of LATS1 by competitive binding of miR-566 to inhibit the growth, invasion and metastasis of HCC cells.

Efficacy and safety of nimotuzumab in addition to radiotherapy and temozolomide for cerebral glioblastoma: a phase II multicenter clinical trial

Background: Nimotuzumab is a humanized anti-epidermal growth factor receptor (EGFR) antibody that has shown preclinical and clinical anticancer activity in cerebral glioblastoma multiforme (GBM). We conducted a phase II, single-arm, multicenter clinical trial to evaluate the benefit of adding nimotuzumab to current standard chemo-radiotherapy for patients with GBM with positive EGFR expression.

Methods: Newly diagnosed patients with histologically proven single supratentorial GBM and epidermal growth factor receptor (EGFR) positive expressions were recruited. All patients were treated with nimotuzumab, administered once a week intravenously for 6 weeks in addition to radiotherapy with concomitant and adjuvant temozolomide after surgery. The primary endpoints were overall survival (OS) and progression-free survival (PFS). Secondary objectives included objective response rate (ORR) and toxicity.

Results: A total of 39 patients were enrolled and 36 patients were evaluated for efficacy. The ORR at the end of RT was 72.2%. Median OS and PFS were 24.5 and 11.9 months. The 1-year OS and PFS rates were 83.3% and 49.3%. The 2-year OS and PFS rates were 51.1% and 29.0%. O (6)-methylquanine DNA methyl-tranferase (MGMT) expression is known to affect the efficacy of chemotherapy and status of its expression is examined. No significant correlation between treatment outcomes and MGMT status was found. Most frequent treatment-related toxicities were mild to moderate and included constipation, anorexia, fatigue, nausea, vomiting, and leucopenia.

Conclusions: Our study show that nimotuzumab in addition to standard treatment is well tolerable and has increased survival in newly diagnosed GBM patients with EGFR positive expression.

Advances in Targeting the Epidermal Growth Factor Receptor Pathway by Synthetic Products and Its Regulation by Epigenetic Modulators As a Therapy for Glioblastoma

Glioma is the most common primary tumor of the nervous system, and approximately 50% of patients exhibit the most aggressive form of the cancer, glioblastoma. The biological function of epidermal growth factor receptor (EGFR) in tumorigenesis and progression has been established in various types of cancers, since it is overexpressed, mutated, or dysregulated. Its overexpression has been shown to be associated with enhanced metastatic potential in glioblastoma, with EGFR at the top of a downstream signaling cascade that controls basic functional properties of glioblastoma cells such as survival, cell proliferation, and migration. Thus, EGFR is considered as an important therapeutic target in glioblastoma. Many anti-EGFR therapies have been investigated both in vivo and in vitro, making their way to clinical studies. However, in clinical trials, the potential efficacy of anti-EGFR therapies is low, primarily because of chemoresistance. Currently, a range of epigenetic drugs including histone deacetylase (HDAC) inhibitors, DNA methylation and histone inhibitors, microRNA, and different types of EGFR inhibitor molecules are being actively investigated in glioblastoma patients as therapeutic strategies. Here, we describe recent knowledge on the signaling pathways mediated by EGFR/EGFR variant III (EGFRvIII) with regard to current therapeutic strategies to target EGFR/EGFRvIII amplified glioblastoma.

Colon Epithelial MicroRNA Network in Fatty Liver

BACKGROUND & AIMS

Intestinal barrier alterations are associated with fatty liver (FL) and metabolic syndrome (MetS), but microRNA (miR) signaling pathways in MetS-FL pathogenesis remain unclear. This study investigates an epithelial-focused miR network in colorectal cell models based on the previously reported MetS-FL miR trio of hsa-miR-142-3p, hsa-miR-18b, and hsa-miR-890.

METHODS

Each miR mimic construct of MetS-FL miR trio was transfected into human colorectal cells, CRL-1790 or Caco-2. Global miRNome changes posttransfection were profiled (nCounter® Human v3 miRNA, NanoString Technologies). Changes in barrier (transepithelial electrical resistance, TEER) and epithelial cell junction structure (Occludin and Zona Occludens-1/ZO-1 immunofluorescence staining-confocal microscopy) were examined pre- and posttransfection in Caco-2 cell monolayers. A signaling network was constructed from the MetS-FL miR trio, MetS-FL miR-induced colorectal miRNome changes, ZO-1, and Occludin.

RESULTS

Transfection of CRL-1790 cells with each MetS-FL miR mimic led to global changes in the cellular miRNome profile, with 288 miRs being altered in expression by more than twofold. Eleven miRs with known cytoskeletal and metabolic roles were commonly altered in expression by all three miR mimics. Transfection of Caco-2 cell monolayers with each MetS-FL miR mimic induced barrier-associated TEER variations and led to structural modifications of ZO-1 and Occludin within epithelial cell junctions. Pathway analysis incorporating the MetS-FL miR trio, eleven common target miRs, ZO-1, and Occludin revealed a signaling network centered on TNF and AKT2, which highlights injury, inflammation, and hyperplasia.

CONCLUSIONS

Colon-specific changes in epithelial barriers, cell junction structure, and a miRNome signaling network are described from functional studies of a MetS-FL miR trio signature.

Regulation of tumor angiogenesis by microRNAs: State of the art

MicroRNAs (miRNAs, miRs) are small (21-25 nucleotides) endogenous and noncoding RNAs involved in many cellular processes such as apoptosis, development, proliferation, and differentiation via binding to the 3'-untranslated region of the target mRNA and inhibiting its translation. Angiogenesis is a hallmark of cancer, which provides oxygen and nutrition for tumor growth while removing deposits and wastes from the tumor microenvironment. There are many angiogenesis stimulators, among which vascular endothelial growth factor (VEGF) is the most well known. VEGF has three tyrosine kinase receptors, which, following VEGF binding, initiate proliferation, invasion, migration, and angiogenesis of endothelial cells in the tumor environment. One of the tumor microenvironment conditions that induce angiogenesis through increasing VEGF and its receptors expression is hypoxia. Several miRNAs have been identified that affect different targets in the tumor angiogenesis pathway. Most of these miRNAs affect VEGF and its tyrosine kinase receptors expression downstream of the hypoxia-inducible Factor 1 (HIF-1). This review focuses on tumor angiogenesis regulation by miRNAs and the mechanism underlying this regulation.

miR-566 functions as an oncogene and a potential biomarker for prognosis in renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC), a heterogeneous type of cancer originating from the nephron, occupies approximately 3.9% of new carcinomas, with an increasing incidence in the past two decades. The most common subtype of renal cell carcinoma is clear cell RCC (ccRCC). Though surgery and other treatments are applied to RCC, it has the highest recurrence rate and mortality rate among the genitourinary cancers. As the study progressed, miRNAs are found to be the biomarkers for tumor diagnosis, prognosis and the targets for tumor management.

METHODS

In present study, RT-qPCR, wound scratch assay, cell proliferation assay, transwell assay and flow cytometry assay were performed to ascertain miR-566 expression level and its proliferation, migration and apoptosis in RCC. Moreover, we analyzed the relation between miR-566 expression and clinicopathological variables or overall survival from the 42 formalin-fixed paraffin-embedded (FFPE) renal cancer samples. We further evaluate prognostic values of miR-566 expression.

RESULTS

miR-566 is up-regulated in RCC tissue samples and renal carcinoma cell lines. miR-566 promotes cell proliferation, mobility and inhibits cell apoptosis in 786-O and ACHN cell lines. Cox proportional hazard regression analysis indicates that low expression of miR-566 patients have a remarkable longer overall survival in the univariate and multivariate analysis. The Kaplan-Meier survival curves show that the low expression of miR-566 patients have a remarkable longer overall survival.

CONCLUSIONS

The results of the current study demonstrate that oncogene miR-566 is a potential biomarker not only for diagnosis but also for prognosis for RCC.

MiR-19 regulates the proliferation and invasion of glioma by RUNX3 via β-catenin/Tcf-4 signaling

Accumulating data demonstrates that the network dysregulation of microRNA-medicated target genes is involved in glioma. We have previously found miR-19a/b overexpression in glioma cell lines and specimens with various tumour grades. However, there was no report on the function and regulatory mechanism of miR-19a/b in glioma. In this study, based on our previous research data, we first determine the inverse relationship between miR-19 (miR-19a and miR-19b) and RUNX3 which is also identified the reduced expression in tumour tissues by real-time PCR and IHC. Luciferase reporter assay and western blot analysis revealed that RUNX3 was a direct target of miR-19. Down-regulation of miR-19 dramatically inhibited proliferation, invasion and induced the cell cycle G1 arrest and apoptosis, at least partly via the up-regulation of RUNX3. Furthermore, Mechanistic investigation indicated that knockdown of miR-19 repressed the β-catenin/TCF4 transcription activity. In conclusion, our study validates a pathogenetic role of miR-19 in glioma and establishes a potentially regulatory and signaling involving miR-19 /RUNX3/β-catenin, also suggesting miR-19 may be a candidate therapeutic target in glioma.

Alu RNA accumulation induces epithelial-to-mesenchymal transition by modulating miR-566 and is associated with cancer progression

Alu sequences are the most abundant short interspersed repeated elements in the human genome. Here we show that in a cell culture model of colorectal cancer (CRC) progression, we observe accumulation of Alu RNA that is associated with reduced DICER1 levels. Alu RNA induces epithelial-to-mesenchymal transition (EMT) by acting as a molecular sponge of miR-566. Moreover, Alu RNA accumulates as consequence of DICER1 deficit in colorectal, ovarian, renal and breast cancer cell lines. Interestingly, Alu RNA knockdown prevents DICER1 depletion-induced EMT despite global microRNA (miRNA) downregulation. Alu RNA expression is also induced by transforming growth factor-β1, a major driver of EMT. Corroborating this data, we found that non-coding Alu RNA significantly correlates with tumor progression in human CRC patients. Together, these findings reveal an unexpected DICER1-dependent, miRNA-independent role of Alu RNA in cancer progression that could bring mobile element transcripts in the fields of cancer therapeutic and prognosis.

Linc00152 promotes malignant progression of glioma stem cells by regulating miR-103a-3p/FEZF1/CDC25A pathway

BACKGROUND

Glioma is one of the most frequent intracranial malignant tumors. LncRNAs have been identified as new modulators in the origination and progression of glioma.

METHODS

Quantitative real-time PCR were conducted to evaluate the expression of linc00152 and miRNA-103a-3p in glioma tissues and cells. Western blot were used to determine the expression of FEZF1 and CDC25A in glioma tissues and cells. Stable knockdown of linc00152 or over-expression of miR-103a-3p in glioma stem cells (GSCs) were established to explore the function of linc00152 and miR-103a-3p in GSCs. Further, luciferase reports were used to investigate the correlation between linc00152 and miR-103a-3p. Cell Counting Kit-8, transwell assays, and flow cytometry were used to investigate the function of linc00152 and miR-103a-3p in GSC malignant biological behaviors. ChIP assays were employed to ascertain the correlations between FEZF1 and CDC25A.

RESULTS

Linc00152 was up-regulated in glioma tissues as well as in GSCs. Knockdown of linc00152 inhibited cell proliferation, migration and invasion, while promoted GSC apoptosis. Linc00152 regulated the malignant behavior of GSCs by binding to miR-103a-3p, which functions as a tumor suppressor. In addition, knockdown of linc00152 down-regulated forebrain embryonic zinc finger protein 1 (FEZF1), a direct target of miR-103a-3p which played an oncogenic role in GSCs. FEZF1 elevated promoter activities and up-regulated expression of the oncogenic gene cell division cycle 25A (CDC25A). CDC25A over-expression activated the PI3K/AKT pathways, which regulated the malignant behavior of GSCs.

CONCLUSIONS

Linc00152/miR-103a-3p/FEZF1/CDC25A axis plays a novel role in regulating the malignant behavior of GSCs, which may be a new potential therapeutic strategy for glioma therapy.

Demethoxycurcumin inhibited human epithelia ovarian cancer cells’ growth via up-regulating miR-551a

Curcumin is a natural agent that has ability to dampen tumor cells’ growth. However, the natural form of curcumin is prone to degrade and unstable in vitro. Here, we demonstrated that demethoxycurcumin (a curcumin-related demethoxy compound) could inhibit cell proliferation and induce apoptosis of ovarian cancer cells. Moreover, IRS2/PI3K/Akt axis was inactivated in cells treated with demethoxycurcumin. Quantitative real-time reverse transcription polymerase chain reaction demonstrated that miR-551a was down-regulated in ovarian cancer tissues and ovarian cancer cell lines. Over-expression of miR-551a inhibited cell proliferation and induced apoptosis of ovarian cancer cells, whereas down-regulation of miR-551a exerted the opposite function. Luciferase assays confirmed that there was a binding site of miR-551a in IRS2, and we found that miR-551a exerted tumor-suppressive function by targeting IRS2 in ovarian cancer cells. Remarkably, miR-551a was up-regulated in the cells treated with demethoxycurcumin, and demethoxycurcumin suppressed IRS2 by restoration of miR-551a. In conclusion, demethoxycurcumin hindered ovarian cancer cells’ malignant progress via up-regulating miR-551a.

HOTAIR is a therapeutic target in glioblastoma

HOTAIR is a negative prognostic factor and is overexpressed in multiple human cancers including glioblastoma multiform (GBM). Survival analysis of Chinese Glioma Genome Atlas (CGGA) patient data indicated that high HOTAIR expression was associated with poor outcome in GBM patients. NLK (Nemo-like kinase), a negative regulator of the β-catenin pathway, was negatively correlated with HOTAIR expression. When the β-catenin pathway was inhibited, GBM cells became susceptible to cell cycle arrest and inhibition of invasion. Introduction of the HOTAIR 5′ domain in human glioma-derived astrocytoma induced β-catenin. An intracranial animal model was used to confirm that HOTAIR depletion inhibited GBM cell migration/invasion. In the orthotopic model, HOTAIR was required for GBM formation in vivo. In summary, HOTAIR is a potential therapeutic target in GBM.

Mining for genes related to choroidal neovascularization based on the shortest path algorithm and protein interaction information

BACKGROUND

Choroidal neovascularization (CNV) is a serious eye disease that may cause visual loss, especially for older people. Many factors have been proven to induce this disease including age, gender, obesity, and so on. However, until now, we have had limited knowledge on CNV's pathogenic mechanism. Discovering the genes that underlie this disease and performing extensive studies on them can help us to understand how CNV occurs and design effective treatments.

METHODS

In this study, we designed a computational method to identify novel CNV-related genes in a large protein network constructed using the protein-protein interaction information in STRING. The candidate genes were first extracted from the shortest paths connecting any two known CNV-related genes and then filtered by a permutation test and using knowledge of their linkages to known CNV-related genes.

RESULTS

A list of putative CNV-related candidate genes was accessed by our method. These genes are deemed to have strong relationships with CNV.

CONCLUSIONS

Extensive analyses of several of the putative genes such as ANK1, ITGA4, CD44 and others indicate that they are related to specific biological processes involved in CNV, implying they may be novel CNV-related genes.

GENERAL SIGNIFICANCE

The newfound putative CNV-related genes may provide new insights into CNV and help design more effective treatments. This article is part of a Special Issue entitled "System Genetics" Guest Editor: Dr. Yudong Cai and Dr. Tao Huang.

Long non-coding RNA HOTAIR promotes glioblastoma cell cycle progression in an EZH2 dependent manner

The long non-coding RNA Hox transcript antisense intergenic RNA (HOTAIR) was recently implicated in breast cancer metastasis and is predictive of poor prognosis in colorectal and pancreatic cancers. We recently discovered that HOTAIR is a cell cycle-related lncRNA in human glioma, and its expression is closely associated with glioma staging and poor prognosis. Although lysine specific demethylase 1 (LSD1) and polycomb repressive complex 2 (PRC2) have been demonstrated to be functional targets of HOTAIR, how HOTAIR regulates glioma cell cycle progression remains largely unknown. In this study, we found that EZH2 (predominant PRC2 complex component) inhibition blocked cell cycle progression in glioma cells, consistent with the effects elicited by HOTAIR siRNA. However, the inhibition of LSD1 did not affect cell cycle progression in glioma cells. These results suggest that HOTAIR might regulate cell cycle progression through EZH2. Our intracranial mice model also revealed delayed tumor growth in HOTAIR siRNA- and EZH2 inhibitor-treated groups. Moreover, in HOTAIR knock-down cell lines, the expression of the PRC2-binding domain of HOTAIR (5′ domain) but not of the LSD1-binding domain of HOTAIR (3′ domain) resulted in accelerated cell cycle progression. In conclusion, HOTAIR promotes cell cycle progression in glioma as a result of the binding of its 5′ domain to the PRC2 complex.

MicroRNA‑566 modulates vascular endothelial growth factor by targeting Von Hippel‑Landau in human glioblastoma in vitro and in vivo

MicroRNAs (miRNAs) are able to function as either oncogenes or tumor suppressor genes in tumorigenesis, and have been proposed as novel targets for anticancer treatment. It has previously been suggested that miRNAs have important roles in the initiation and progression of glioblastoma; however, the effects of miR‑566 in glioblastoma are currently unclear. The present study aimed to demonstrate that miR-566 can modulate vascular endothelial growth factor (VEGF) by targeting Von Hippel‑Lindau (VHL) in glioblastoma in vitro and in vivo by inhibiting the expression of miR-566. Glioblastoma is a highly vascularized tumor, which exhibits increased expression of angiogenic factors, including VEGF, which are crucial in the process of glioblastoma angiogenesis. Existing research has demonstrated that VHL is a tumor suppressor gene that is associated with various tumors. In addition, VHL is able to regulate the expression of VEGF by promoting the degradation of hypoxia‑inducible factor‑1α via ubiquitination. It has been predicted, using bioinformatics, that the VHL gene is regulated by miR‑566. Therefore, the present study hypothesized that miR‑566 may regulate VEGF expression by targeting VHL during the angiogenic process of glioblastoma multiforme. The results of the present study demonstrated that inhibition of miR‑566 expression increases the expression levels of VHL, decreases the expression levels of VEGF, and inhibits the invasive and migratory abilities of glioblastoma. In addition, VHL was identified as a functional target of miR‑566.

MicroRNAs and Growth Factors: An Alliance Propelling Tumor Progression

Tumor progression requires cancer cell proliferation, migration, invasion, and attraction of blood and lymph vessels. These processes are tightly regulated by growth factors and their intracellular signaling pathways, which culminate in transcriptional programs. Hence, oncogenic mutations often capture growth factor signaling, and drugs able to intercept the underlying biochemical routes might retard cancer spread. Along with messenger RNAs, microRNAs play regulatory roles in growth factor signaling and in tumor progression. Because growth factors regulate abundance of certain microRNAs and the latter modulate the abundance of proteins necessary for growth factor signaling, the two classes of molecules form a dense web of interactions, which are dominated by a few recurring modules. We review specific examples of the alliance formed by growth factors and microRNAs and refer primarily to the epidermal growth factor (EGF) pathway. Clinical applications of the crosstalk between microRNAs and growth factors are described, including relevance to cancer therapy and to emergence of resistance to specific drugs.

Interactional role of microRNAs and bHLH-PAS proteins in cancer (Review)

MicroRNAs (miRNAs) are recognized as an emerging class of master regulators that regulate human gene expression at the post-transcriptional level and are involved in many normal and pathological cellular processes. Mammalian basic HLH (helix-loop-helix)-PER-ARNT-SIM (bHLH-PAS) proteins are heterodimeric transcriptional regulators that sense and respond to environmental signals (such as chemical pollutants) or to physiological signals (for instance hypoxia). In the normal state, bHLH-PAS proteins are responsible for multiple critical aspects of physiology to ensure the cell accurate homeostasis, but dysregulation of these proteins has been shown to contribute to carcinogenic events such as tumor initiation, promotion, and progression. Increasing epidemiological and experimental studies have shown that bHLH-PAS proteins regulate a panel of miRNAs, whereas some miRNAs also target bHLH-PAS proteins. The interaction between miRNAs and certain bHLH-PAS proteins [hypoxia-inducible factor (HIF) and aryl hydrocarbon receptor (AHR)] is relevant to many vital events associated with tumorigenesis. This review will summarize recent findings on the interesting and complicated underlying mechanisms that miRNAs interact with HIFs or AHR in tumors, hopefully to benefit the discovery of novel drug-interfering targets for cancer therapy.

Role of runt-related transcription factor 2 in signal network of tumors as an inter-mediator

Runt-related transcription factor 2 (RUNX2) is a member of the polyomavirus enhancer-binding protein 2/core-binding factor superfamily. RUNX2 is known for its contribution to osteoblast phenotype and bone formation. In recent years, increasing attention has been focused on the relationship of Runx2 with tumorigenesis. In different types of tumor cells, RUNX2 cooperates with its co-activators or co-inhibitors, and mediates the responses of cells to various signaling pathways that are hyperactive in tumors. Thus, several downstream target genes of RUNX2 are activated when RUNX2 interacts with its co-factors, leading to a variety of effects on tumor cells (epithelial-mesenchymal transition, metastasis, proliferation, and osteolytic lesion). This review focuses on the involvement of RUNX2 in tumor cells in the crosstalk of diverse signaling pathways and its multiple functions to develop optimal and feasible approaches for clinical treatment based on the functions of RUNX2.

ICAT inhibits glioblastoma cell proliferation by suppressing Wnt/β-catenin activity

Inhibitor of β-catenin and T-cell factor (ICAT) is a key component of Wnt/β-catenin signaling. ICAT blocks the formation of the β-catenin/TCF complex and has been demonstrated to be involved in embryonic development and carcinogenesis. As an inhibitor of canonical Wnt signaling, ICAT was presumed to be a tumor-suppressor gene. However, the ICAT functions in human glioma remain unknown. In this study, we evaluated the expression of ICAT in 305 human glioma tissues and found that negative ICAT expression correlated with higher grade glioma and poor survival in patients with glioma. Then we transfected glioma cells with ICAT plasmid. Western blotting showed an increased ICAT protein expression level in glioma cells. MTT assay, flow cytometry and cell invasion assay were used to detect cell proliferation, cell cycle distribution, apoptosis and invasion. Our studies confirmed that ICAT inhibits glioma cell proliferation and invasion, and it induces cell apoptosis and cell cycle progression arrest. Besides, ICAT slowed down tumor growth in a glioblastoma xenograft model. Therefore, our study demonstrates that ICAT may serve as a tumor-suppressor in human glioma suggesting a promising direction for targeting therapy in glioma.

MicroRNA-7 directly targets insulin-like growth factor 1 receptor to inhibit cellular growth and glucose metabolism in gliomas

BACKGROUND

Recent studies observed that altered energy metabolism has become widespread in cancer cells along with other cancer-associated traits that have been accepted as hallmarks of cancer. Akt signaling pathway is involved in the aerobic glycolysis program. However, mechanisms underlying the regulation of aerobic glycolysis and Akt activity in gliomas remain unclear. MicroRNAs are a group of small non-coding RNAs that can function as endogenous RNA interference to regulate expression of targeted genes. This study was conducted to detect the function of miR-7 targeting insulin-like growth factor 1 receptor (IGF-1R), which is an upstream regulator of Akt.

METHODS

MicroRNA expression data for gliomas and normal controls were downloaded from The Cancer Genome Atlas (TCGA) database. Quantitative real-time PCR was used to measure the microRNA-7 (miR-7) expression level, and Western blot was performed to detect protein expression in U87 and U251 cells. Colony formation assay and glycolysis stress test were also conducted. Luciferase reporter assay was used to identify the mechanism of IGF-1R and miR-7 regulation.

RESULTS

miR-7 was downregulated in human glioma tissues based on TCGA database. Forced expression of miR-7 or IGF-1R knockdown inhibited colony formation and glucose metabolic capabilities of glioma cells in vitro and decreased the p-Akt expression level. Bioinformatics analysis results indicated that IGF-1R could be a target of miR-7. Western blot and luciferase reporter assays showed that miR-7 modulated IGF-1R expression by directly targeting the binding site within the 3'-untranslated region.

CONCLUSIONS

This study provides the first evidence that miR-7 inhibits cellular growth and glucose metabolism in gliomas, at least partially, by regulating the IGF-1R/Akt signaling pathway. Therefore, miR-7 is a promising molecular drug for glioma treatment.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_211.