MiR-29b downregulates canonical Wnt signaling by suppressing coactivators of β-catenin in human colorectal cancer cells

Role of Angiogenesis and Its Biomarkers in Development of Targeted Tumor Therapies

Angiogenesis plays a significant role in the human body, from wound healing to tumor progression. "Angiogenic switch" indicates a time-restricted event where the imbalance between pro- and antiangiogenic factors results in the transition from prevascular hyperplasia to outgrowing vascularized tumor, which eventually leads to the malignant cancer progression. In the last decade, molecular players, i.e., angiogenic biomarkers and underlying molecular pathways involved in tumorigenesis, have been intensely investigated. Disrupting the initiation and halting the progression of angiogenesis by targeting these biomarkers and molecular pathways has been considered as a potential treatment approach for tumor angiogenesis. This review discusses the currently known biomarkers and available antiangiogenic therapies in cancer, i.e., monoclonal antibodies, aptamers, small molecular inhibitors, miRNAs, siRNAs, angiostatin, endostatin, and melatonin analogues, either approved by the U.S. Food and Drug Administration or currently under clinical and preclinical investigations.

Exosome-based crosstalk in glaucoma pathogenesis: a focus on oxidative stress and neuroinflammation

Exosomes are membrane-bound tiny particles that are released by all live cells that contain multiple signal molecules and extensively participate in numerous normal physical activities and pathologies. In glaucoma, the crucial role of exosome-based crosstalk has been primarily revealed in animal models and ex vivo cell studies in the recent decade. In the aqueous drainage system, exosomes derived from non-pigment ciliary epithelium act in an endocrine manner and specifically regulate the function of the trabecular meshwork to cope with persistent oxidative stress challenges. In the retina, a more complicated regulatory network among microglia, retinal neurons, retinal ganglial cells, retinal pigment epithelium, and other immune effector cells by exosomes are responsible for the elaborate modulation of tissue homeostasis under physical state and the widespread propagation of neuroinflammation and its consequent neurodegeneration in glaucoma pathogenesis. Accumulating evidence indicates that exosome-based crosstalk depends on numerous factors, including the specific cargos they carried (particularly micro RNA), concentration, size, and ionization potentials, which largely remain elusive. In this narrative review, we summarize the latest research focus of exosome-based crosstalk in glaucoma pathogenesis, the current research progress of exosome-based therapy for glaucoma and provide in-depth perspectives on its current research gap.

Exosomes in metastasis of colorectal cancers: Friends or foes?

Colorectal cancer (CRC), the third most common type of cancer worldwide, threaten human health and quality of life. With multidisciplinary, including surgery, chemotherapy and/or radiotherapy, patients with an early diagnosis of CRC can have a good prognosis. However, metastasis in CRC patients is the main risk factor causing cancer-related death. To elucidate the underlying molecular mechanisms of CRC metastasis is the difficult and research focus on the investigation of the CRC mechanism. On the other hand, the tumor microenvironment (TME) has been confirmed as having an essential role in the tumorigenesis and metastasis of malignancies, including CRCs. Among the different factors in the TME, exosomes as extracellular vesicles, function as bridges in the communication between cancer cells and different components of the TME to promote the progression and metastasis of CRC. MicroRNAs packaged in exosomes can be derived from different sources and transported into the TME to perform oncogenic or tumor-suppressor roles accordingly. This article focuses on CRC exosomes and illustrates their role in regulating the metastasis of CRC, especially through the packaging of miRNAs, to evoke exosomes as novel biomarkers for their impact on the metastasis of CRC progression.

EVADR ceRNA transcript variants upregulate WNT and PI3K signaling pathways in SW480 and HCT116 cells by sponging miR-7 and miR-29b

Long noncoding RNAs are cancer regulators and EVADR-lncRNA is highly upregulated in colorectal cancer (CRC). Accordingly, we aimed to functionally characterize the EVADR in CRC-originated cells. Firstly, during the amplification of EVADR full-length cDNA (named EVADR-v1), a novel/shorter variant (EVADR-v2) was discovered. Then, RT-qPCR analysis confirmed that EVADR is upregulated in tumors, consistent with RNA-seq analysis. Interestingly, bioinformatics analysis and dual-luciferase assay verified that EVADR sponges miR-7 and miR-29b. When both EVADR-v1/-v2 variants were overexpressed in SW480/HCT116 cells, miR-7 and miR-29b target genes (involved in the WNT/PI3K signaling) were upregulated. Furthermore, EVADR-v1/-v2 overexpression resulted in elevated PI3K activity (verified by western blotting and RT-qPCR) and upregulation of WNT signaling (confirmed by western blotting, TopFlash assay, and RT-qPCR). Consistently, overexpression of EVADR-v1/-v2 variants was followed by increased cell cycle progression, viability and migration as well as reduced early/late apoptotic rate, and Bax/Bcl2 ratio of the CRC cells, detected by the cell cycle analysis, MTT, wound-healing, Annexin-V/PI, and RT-qPCR methods, respectively. Overall, we introduced two oncogenic transcript variants for EVADR that by sponging miR-7/miR-29b, upregulate WNT and PI3K signaling. Given the crucial role of these pathways in CRC, EVADR may present potential therapy use.

Classical Angiogenic Signaling Pathways and Novel Anti-Angiogenic Strategies for Colorectal Cancer

Although productive progress has been made in colorectal cancer (CRC) researchs, CRC is the second most frequent type of malignancy and the major cause of cancer-related death among gastrointestinal cancers. As angiogenesis constitutes an important point in the control of CRC progression and metastasis, understanding the key signaling pathways that regulate CRC angiogenesis is critical in elucidating ways to inhibit CRC. Herein, we comprehensively summarized the angiogenesis-related pathways of CRC, including vascular endothelial growth factor (VEGF), nuclear factor-kappa B (NF-κB), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), Wingless and int-1 (Wnt), and Notch signaling pathways. We divided the factors influencing the specific pathway into promoters and inhibitors. Among these, some drugs or natural compounds that have antiangiogenic effects were emphasized. Furthermore, the interactions of these pathways in angiogenesis were discussed. The current review provides a comprehensive overview of the key signaling pathways that are involved in the angiogenesis of CRC and contributes to the new anti-angiogenic strategies for CRC.

Epigenetic Regulation of the Wnt/β-Catenin Signaling Pathway in Cancer

Studies over the past four decades have elucidated the role of Wnt/β-catenin mediated regulation in cell proliferation, differentiation and migration. These processes are fundamental to embryonic development, regeneration potential of tissues, as well as cancer initiation and progression. In this review, we focus on the epigenetic players which influence the Wnt/β-catenin pathway via modulation of its components and coordinated regulation of the Wnt target genes. The role played by crosstalk with other signaling pathways mediating tumorigenesis is also elaborated. The Hippo/YAP pathway is particularly emphasized due to its extensive crosstalk via the Wnt destruction complex. Further, we highlight the recent advances in developing potential therapeutic interventions targeting the epigenetic machinery based on the characterization of these regulatory networks for effective treatment of various cancers and also for regenerative therapies.

MiRNA-Wnt signaling regulatory network in colorectal cancer

Colorectal cancer (CRC) is one of the common malignancies worldwide and the Wnt signaling pathway is recognized as the main disrupted pathway in this malignancy. MicroRNAs (miRNAs) are recognized to contribute to the pathogenesis of CRC by triggering or impeding the Wnt signaling pathway. In addition, transcriptional regulation of miRNAs by canonical Wnt signaling also participates in CRC cell progression. In this review, we present comprehensive literature of the existing data on the interaction of miRNAs and Wnt signaling that could be useful in future studies in the field of CRC management.

Overexpression of microRNA-29b inhibits epithelial-mesenchymal transition and angiogenesis of colorectal cancer through the ETV4/ERK/EGFR axis

BACKGROUND

Recent studies have reported the involvement of microRNA-29 (miR-29) family members in human cancers through their ability to regulate cellular functions. The present study investigated biological function of miR-29b in colorectal cancer (CRC).

METHODS

CRC tissues and adjacent normal tissues were collected and the expression of ETV4 and miR-29b in the tissues were identified. The relationship between ETV4 and miR-29b or ETV4 expression and the EGFR promoter was identified using dual-luciferase reporter gene and CHIP assays. The proliferation, invasion, migration, and apoptosis of CRC HCT116 cells were assayed using MTT assay, Scratch test, Transwell assay, and flow cytometry, respectively. Also, expression of epithelial-mesenchymal transition (EMT) markers, angiogenic factors, and vasculogenic mimicry formation were evaluated using RT-qPCR and Western blot.

RESULTS

ETV4 was upregulated, while miR-29b expression was decreased in CRC tissues. ETV4 was identified as a target gene of miR-29b, which in turn inactivated the ERK signaling pathway by targeting ETV4 and inhibiting EGFR transcription. Transfection with miR-29b mimic, siRNA-ETV4, or ERK signaling pathway inhibitor U0126 increased expression of E-cadherin and TSP-1, and CRC cell apoptosis, yet reduced expression of ERK1/2, MMP-2, MMP-9, Vimentin, and VEGF, as well as inhibiting EMT, angiogenesis, and CRC cell migration and invasion. The EMT, angiogenesis and cancer progression induced by miR-29b inhibitor were reversed by siRNA-mediated ETV4 silencing.

CONCLUSIONS

miR-29b suppresses angiogenesis and EMT in CRC via the ETV4/ERK/EGFR axis.

Angiogenesis-Related Functions of Wnt Signaling in Colorectal Carcinogenesis

Simple Summary

Angiogenesis belongs to the most clinical characteristics of colorectal cancer (CRC) and is strongly linked to the activation of Wnt/β-catenin signaling. The most prominent factors stimulating constitutive activation of this pathway, and in consequence angiogenesis, are genetic alterations (mainly mutations) concerning APC and the β-catenin encoding gene (CTNNB1), detected in a large majority of CRC patients. Wnt/β-catenin signaling is involved in the basic types of vascularization (sprouting and nonsprouting angiogenesis), vasculogenic mimicry as well as the formation of mosaic vessels. The number of known Wnt/β-catenin signaling components and other pathways interacting with Wnt signaling, regulating angiogenesis, and enabling CRC progression continuously increases. This review summarizes the current knowledge about the role of the Wnt/Fzd/β-catenin signaling pathway in the process of CRC angiogenesis, aiming to improve the understanding of the mechanisms of metastasis as well as improvements in the management of this cancer.

Abstract

Aberrant activation of the Wnt/Fzd/β-catenin signaling pathway is one of the major molecular mechanisms of colorectal cancer (CRC) development and progression. On the other hand, one of the most common clinical CRC characteristics include high levels of angiogenesis, which is a key event in cancer cell dissemination and distant metastasis. The canonical Wnt/β-catenin downstream signaling regulates the most important pro-angiogenic molecules including vascular endothelial growth factor (VEGF) family members, matrix metalloproteinases (MMPs), and chemokines. Furthermore, mutations of the β-catenin gene associated with nuclear localization of the protein have been mainly detected in microsatellite unstable CRC. Elevated nuclear β-catenin increases the expression of many genes involved in tumor angiogenesis. Factors regulating angiogenesis with the participation of Wnt/β-catenin signaling include different groups of biologically active molecules including Wnt pathway components (e.g., Wnt2, DKK, BCL9 proteins), and non-Wnt pathway factors (e.g., chemoattractant cytokines, enzymatic proteins, and bioactive compounds of plants). Several lines of evidence argue for the use of angiogenesis inhibition in the treatment of CRC. In the context of this paper, components of the Wnt pathway are among the most promising targets for CRC therapy. This review summarizes the current knowledge about the role of the Wnt/Fzd/β-catenin signaling pathway in the process of CRC angiogenesis, aiming to improve the understanding of the mechanisms of metastasis as well as improvements in the management of this cancer.

Extracellular vesicle-mediated crosstalk between NPCE cells and TM cells result in modulation of Wnt signalling pathway and ECM remodelling

Primary open-angle glaucoma is a leading cause of irreversible blindness, often associated with increased intraocular pressure. Extracellular vesicles (EVs) carry a specific composition of proteins, lipids and nucleotides have been considered as essential mediators of cell-cell communication. Their potential impact for crosstalk between tissues responsible for aqueous humour production and out-flow is largely unknown. The study objective was to investigate the effects of EVs derived from non-pigmented ciliary epithelium (NPCE) primary cells on the expression of Wnt proteins in a human primary trabecular meshwork (TM) cells and define the mechanism underlying exosome-mediated regulation that signalling pathway. Consistent with the results in TM cell line, EVs released by both primary NPCE cells and NPCE cell line showed diminished pGSK3β phosphorylation and decreased cytosolic levels of β-catenin in primary TM cells. At the molecular level, we showed that NPCE exosome treatment downregulated the expression of positive GSKβ regulator-AKT protein but increased the levels of GSKβ negative regulator-PP2A protein in TM cells. NPCE exosome protein analysis revealed 584 miRNAs and 182 proteins involved in the regulation of TM cellular processes, including WNT/β-catenin signalling pathway, cell adhesion and extracellular matrix deposition. We found that negative modulator of Wnt signalling miR-29b was abundant in NPCE exosomal samples and treatment of TM cells with NPCE EVs significantly decreased COL3A1 expression. Suggesting that miR-29b can be responsible for decreased levels of WNT/β-catenin pathway. Overall, this study highlights a potential role of EVs derived from NPCE cells in modulating ECM proteins and TM canonical Wnt signalling.

Mast Cell Protease 7 Promotes Angiogenesis by Degradation of Integrin Subunits

Previous studies from our laboratory have shown that during angiogenesis in vitro, rmMCP-7 (recombinant mouse mast cell protease-7) stimulates endothelial cell spreading and induces their penetration into the matrix. The ability of rmMCP-7 to induce angiogenesis in vivo was assessed in the present study using a directed in vivo angiogenesis assay (DIVAA™). Vessel invasion of the angioreactor was observed in the presence of rmMCP-7 but was not seen in the control. Since integrins are involved in endothelial cell migration, the relationship between rmMCP-7 and integrins during angiogenesis was investigated. Incubation with rmMCP-7 resulted in a reduction in the levels of integrin subunits αv and β1 on SVEC4-10 endothelial cells during angiogenesis in vitro. Furthermore, the degradation of integrin subunits occurs both through the direct action of rmMCP-7 and indirectly via the ubiquitin/proteasome system. Even in the presence of a proteasome inhibitor, incubation of endothelial cells with rmMCP-7 induced cell migration and tube formation as well as the beginning of loop formation. These data indicate that the direct degradation of the integrin subunits by rmMCP-7 is sufficient to initiate angiogenesis. The results demonstrate, for the first time, that mMCP-7 acts in angiogenesis through integrin degradation.

The Impact of miRNA in Colorectal Cancer Progression and Its Liver Metastases

Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies with a high incidence and mortality rate. An essential challenge in colorectal cancer management is to identify new prognostic factors that could better estimate the evolution and treatment responses of this disease. Considering their role in cancer development, progression and metastasis, miRNAs have become an important class of molecules suitable for cancer biomarkers discovery. We performed a systematic search of studies investigating the role of miRNAs in colorectal progression and liver metastasis published until October 2018. In this review, we present up-to-date information regarding the specific microRNAs involved in CRC development, considering their roles in alteration of Wnt/βcatenin, EGFR, TGFβ and TP53 signaling pathways. We also emphasize the role of miRNAs in controlling the epithelial⁻mesenchymal transition of CRC cells, a process responsible for liver metastasis in a circulating tumor cell-dependent manner. Furthermore, we discuss the role of miRNAs transported by CRC-derived exosomes in mediating liver metastases, by preparing the secondary pre-metastatic niche and in inducing liver carcinogenesis in a Dicer-dependent manner.

β-catenin regulates IRF3-mediated innate immune signalling in colorectal cancer

OBJECTIVE

β-catenin is one of the most critical oncogenes associated with many kinds of human cancers, especially in the human CRC. Innate immunity recognizes tumour derived damage-associated molecular patterns (DAMPs) and primes the anti-tumour adaptive responses. While the function of β-catenin in CRC tumourigenesis is well established, its impact on innate immune evasion is largely unknown. The aim of this study is to characterize the role of β-catenin in inhibiting RIG-I-like receptor (RLR)-mediated IFN-β signalling in colorectal cancer.

MATERIALS AND METHODS

Immunohistochemical staining and western blotting were conducted to study the expression of β-catenin, IRF3 and phospho-IRF3 (p-IRF3) in CRC samples and cell lines. Plaque assay determining virus replication was performed to assess the regulation of β-catenin on IFN-β signalling. The inhibition of β-catenin on RLR-mediated IFN-β signalling was further studied by real-time analyses and reporter assays in the context of lentiviral-mediated β-catenin stably knocking down. Lastly, co-immunoprecipitation and nuclear fractionation assay were conducted to monitor the interaction between β-catenin and IRF3.

RESULTS

We found that high expression of β-catenin positively correlated with the expression of IRF3 in CRC cells. Overexpression of β-catenin increased the viral replication. Conversely knocking down of β-catenin inhibited viral replication. Furthermore, our data demonstrated that β-catenin could inhibit the expression of IFN-β and interferon-stimulated gene 56 (ISG56). Mechanistically, we found that β-catenin interacted with IRF3 and blocked its nuclear translocation.

CONCLUSION

Our study reveals an unprecedented role of β-catenin in enabling innate immune evasion in CRC.

LncRNA H19/miR-29b-3p/PGRN Axis Promoted Epithelial-Mesenchymal Transition of Colorectal Cancer Cells by Acting on Wnt Signaling

This investigation was aimed at working out the combined role of lncRNA H19, miR-29b and Wnt signaling in the development of colorectal cancer (CRC). In the aggregate, 185 CRC tissues and corresponding para-carcinoma tissues were gathered. The human CRC cell lines (i.e. HT29, HCT116, SW480 and SW620) and normal colorectal mucosa cell line (NCM460) were also purchased. Si-H19, si-NC, miR-29b-3p mimics, miR-29b-3p inhibitor, si-PGRN and negative control (NC) were, respectively, transfected into the CRC cells. Lucif-erase reporter plasmids were prepared to evaluate the transduction activity of Wnt/β-catenin signaling pathway, and dual-luciferase reporter gene assay was arranged to confirm the targeted relationship between H19 and miR-29b-3p, as well as between miR-29b-3p and PGRN. Finally, the proliferative and invasive capacities of CRC cells were appraised through transwell, MTT and scratch assays. As a result, over-expressed H19 and down-expressed miR-29b-3p displayed close associations with the CRC patients' poor prognosis (P < 0.05). Besides, transfection with si-H19, miR-29b-3p mimic or si-PGRN were correlated with elevated E-cadherin expression, decreased snail and vimentin expressions, as well as less-motivated cell proliferation and cell metastasis (P < 0.05). Moreover, H19 was verified to directly target miR-29b-3p based on the luciferase reporter gene assay (P < 0.05), and miR-29b-3p also bound to PGRN in a direct manner (P < 0.05). Finally, addition of LiCl (Wnt/β-catenin pathway activator) or XAV93920 (Wnt/β-catenin pathway inhibitor) would cause remarkably altered E-cadherin, c-Myc, vimentin and snail expressions, as well as significantly changed transcriptional activity of β-catenin/Tcf reporter plasmid (P < 0.05). In conclusion, the lncRNA H19/miR-29b-3p/PGRN/Wnt axis counted a great deal for seeking appropriate diagnostic biomarkers and treatment targets for CRC.

Down-regulation of miR-29b in carcinoma associated fibroblasts promotes cell growth and metastasis of breast cancer

Carcinoma associated fibroblasts (CAFs) play important roles in breast cancer development and progression. Recent studies show that microRNAs (miRNAs) are the main regulators in CAFs. MiR-29b is one of the significant down-regulated miRNAs in CAFs from the miRNA screening. The role of miR-29b in the interaction between CAFs and breast cancer is still unclear. In the present study, we investigated the effects of CAFs on breast cancer cell proliferation and metastasis regulated by miR-29b. We found that fibroblasts activated by co-cultured breast cancer cells produced higher levels of some chemokines like CCL11, CXCL14, which accelerated breast cancer cell growth and induced drug resistance and metastasis. Increased miR-29b expression in activated fibroblasts could suppress the activating p38-STAT1 signal pathway in breast cancer cells. We also found that the expression of CCL11 and CXCL14 could be regulated by miR-29b in CAFs. Our results illustrate that down-regulation of miR-29b in CAFs plays an important role in tumor stroma by activating p38-STAT1 in breast cancer cells. The study indicates that cancer cells and fibroblasts interaction promotes breast cancer cell growth, drug resistance, migration and invasion due to the lack of miR-29b expression in CAFs.

MicroRNA-494 promotes cancer progression and targets adenomatous polyposis coli in colorectal cancer

Background

Aberrant activation of the Wnt/β-catenin signaling pathway is frequently observed in colorectal cancer (CRC). β-catenin is the major Wnt signaling pathway effector and inactivation of adenomatous polyposis coli (APC) results in nuclear accumulation of β-catenin. It has been suggested that inactivation of APC plays an important role in activation of the Wnt/β-catenin pathway and in the progression of colorectal tumorigenesis. However, the mechanism through which APC mediates colorectal tumorigenesis is not understood. Increasing evidence suggests that the dysregulation of microRNAs (miRNAs) is involved in colorectal tumorigenesis. Although miR-494 has been reported as being an upregulated miRNA, the interplay between miR-494 and APC-mediated colorectal tumorigenesis progression remains unclear.

Methods

The expression of miR-494 in tissues from patients diagnosed with CRC was analyzed using a microarray and real-time PCR. The effects of miR-494 on cell proliferation and tumorigenesis in CRC cells were analyzed by flow cytometry, colony formation assays, BrdU incorporation assays, and CCK8 assays. The correlation between miR-494 expression and APC expression, as well as the mechanisms by which miR-494 regulates APC in CRC were also addressed.

Results

miR-494 was significantly upregulated in CRC tissues, and this increase was negatively associated with APC expression. APC was confirmed to be a direct target of miR-494 in CRC. Furthermore, overexpression of miR-494 induced Wnt/β-catenin signaling by targeting APC, thus promoting CRC cell growth.

Conclusions

This study provides novel insights into the role of miR-494 in controlling CRC cell proliferation and tumorigenesis, and identifies miR-494 as a potential prognostic marker and therapeutic target.

MicroRNAs in the etiology of colorectal cancer: pathways and clinical implications

MicroRNAs (miRNAs) are small single-stranded RNAs that repress mRNA translation and trigger mRNA degradation. Of the ∼1900 miRNA-encoding genes present in the human genome, ∼250 miRNAs are reported to have changes in abundance or altered functions in colorectal cancer. Thousands of studies have documented aberrant miRNA levels in colorectal cancer, with some miRNAs reported to actively regulate tumorigenesis. A recurrent phenomenon with miRNAs is their frequent participation in feedback loops, which probably serve to reinforce or magnify biological outcomes to manifest a particular cellular phenotype. Here, we review the roles of oncogenic miRNAs (oncomiRs), tumor suppressive miRNAs (anti-oncomiRs) and miRNA regulators in colorectal cancer. Given their stability in patient-derived samples and ease of detection with standard and novel techniques, we also discuss the potential use of miRNAs as biomarkers in the diagnosis of colorectal cancer and as prognostic indicators of this disease. MiRNAs also represent attractive candidates for targeted therapies because their function can be manipulated through the use of synthetic antagonists and miRNA mimics.

Summary: This Review provides an overview of some important microRNAs and their roles in colorectal cancer.

Mir-29b Mediates the Neural Tube versus Neural Crest Fate Decision during Embryonic Stem Cell Neural Differentiation

During gastrulation, the neuroectoderm cells form the neural tube and neural crest. The nervous system contains significantly more microRNAs than other tissues, but the role of microRNAs in controlling the differentiation of neuroectodermal cells into neural tube epithelial (NTE) cells and neural crest cells (NCCs) remains unknown. Using embryonic stem cell (ESC) neural differentiation systems, we found that miR-29b was upregulated in NTE cells and downregulated in NCCs. MiR-29b promoted the differentiation of ESCs into NTE cells and inhibited their differentiation into NCCs. Accordingly, the inhibition of miR-29b significantly inhibited the differentiation of NTE cells. A mechanistic study revealed that miR-29b targets DNA methyltransferase 3a (Dnmt3a) to regulate neural differentiation. Moreover, miR-29b mediated the function of Pou3f1, a critical neural transcription factor. Therefore, our study showed that the Pou3f1-miR-29b-Dnmt3a regulatory axis was active at the initial stage of neural differentiation and regulated the determination of cell fate.

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MiR-29b promoted NTE differentiation and inhibited NCC differentiation from ESCs

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MiR-29b targeted Dnmt3a to regulate neural differentiation

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MiR-29b mediated the function of Pou3f1

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The Pou3f1-miR-29b-Dnmt3a axis regulated the cell fate determination

The repressive effect of miR-148a on Wnt/β-catenin signaling involved in Glabridin-induced anti-angiogenesis in human breast cancer cells

Background

Glabridin (GLA), a major component extracted from licorice root, has anti-inflammatory and antioxidant activities, but few studies report its mechanism of inhibition of angiogenesis. This study was an extension of our previous work, which demonstrated that GLA suppressed angiogenesis in human breast cancer (MDA-MB-231 and Hs-578T) cells. Breast cancer is one of the most common malignant diseases in females worldwide, and the major cause of mortality is metastasis that is primarily attributed to angiogenesis. Thus, anti-angiogenesis has become a strategy for the treatment of breast cancer.

Methods

Cell viability of different concentration treatment groups were detected by Cell Counting Kit-8 assay. The expression of several related genes in the Wnt1 signaling pathway in MDA-MB-231 and Hs-578T cells treated with GLA were measured at both the transcription and translation levels using quantitative real-time PCR analyses and western blotting. Immunofluorescence assay analyzed the nuclear translocation of β-catenin. The microRNA-inhibitor was used to knockdown microRNA-148a (miR-148a) expression. Angiogenic potentials of breast cancer cells were analyzed by enzyme-linked immunosorbent assay (ELISA) and tube formation in vitro.

Results

GLA attenuated angiogenesis by the suppression of miR-148a-mediated Wnt/β-catenin signaling pathway in two human breast cancer cell lines (MDA-MB-231 and Hs-578T). GLA also upregulated the expression of miR-148a in a dose-dependent manner, miR-148a, which could directly target Wnt-3′-untranslated regions (UTRs), and decreased the expression of Wnt1, leading to β-catenin accumulation in the membranes from the cytoplasm and nucleus. Downregulation of miR-148a contributed to the reduction of GLA-induced suppression of the Wnt/β-catenin signaling pathway, the angiogenesis and vascular endothelial grow factor (VEGF) secretion.

Conclusions

Our study identified a molecular mechanism of the GLA inhibition of angiogenesis through the Wnt/β-catenin signaling pathway via miR-148a, suggesting that GLA could serve as an adjuvant chemotherapeutic agent for breast cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3298-1) contains supplementary material, which is available to authorized users.

Regulatory miRNAs in Colorectal Carcinogenesis and Metastasis

Colorectal cancer is one of the most common malignancies and is the second-leading cause of cancer-related death world-wide, which is linked to genetic mutations, epigenetic alterations, and oncogenic signaling activation. MicroRNAs, one of the categories of epigenetics, have been demonstrated significant roles in carcinogenesis and progression through regulating of oncogenic signaling pathways, stem cells, epithelial-mesenchymal transition, and metastasis. This review summarizes the roles of microRNAs in the regulating of Wnt, Ras, TGF-β, and inflammatory signaling pathways, stemness, and epithelial-mesenchymal transition, for carcinogenesis and metastasis in colorectal cancer. Improving our understanding of the mechanisms of regulatory interactions of microRNAs with signaling pathways in colorectal cancer formation and progression will aid in determining the genes responsible for colorectal cancer initiation, progression, metastasis, and recurrence and, finally, in developing personalized approaches for cancer prevention and therapy.

Wnt-signalling pathways and microRNAs network in carcinogenesis: experimental and bioinformatics approaches

Over the past few years, microRNAs (miRNAs) have not only emerged as integral regulators of gene expression at the post-transcriptional level but also respond to signalling molecules to affect cell function(s). miRNAs crosstalk with a variety of the key cellular signalling networks such as Wnt, transforming growth factor-β and Notch, control stem cell activity in maintaining tissue homeostasis, while if dysregulated contributes to the initiation and progression of cancer. Herein, we overview the molecular mechanism(s) underlying the crosstalk between Wnt-signalling components (canonical and non-canonical) and miRNAs, as well as changes in the miRNA/Wnt-signalling components observed in the different forms of cancer. Furthermore, the fundamental understanding of miRNA-mediated regulation of Wnt-signalling pathway and vice versa has been significantly improved by high-throughput genomics and bioinformatics technologies. Whilst, these approaches have identified a number of specific miRNA(s) that function as oncogenes or tumour suppressors, additional analyses will be necessary to fully unravel the links among conserved cellular signalling pathways and miRNAs and their potential associated components in cancer, thereby creating therapeutic avenues against tumours. Hence, we also discuss the current challenges associated with Wnt-signalling/miRNAs complex and the analysis using the biomedical experimental and bioinformatics approaches.

MicroRNA-214 suppresses growth, migration and invasion through a novel target, high mobility group AT-hook 1, in human cervical and colorectal cancer cells

Background:

MicroRNA-214 (miR-214) has been shown to act as a tumour suppressor in human cervical and colorectal cancer cells. The aim of this study was to experimentally validate high mobility group AT-hook 1 as a novel target for miR-214-mediated suppression of growth and motility.

Methods:

HMGA1 and miR-214 expression levels were estimated in cervical and colorectal clinical specimens using qPCR. HMGA1 3′ untranslated region luciferase assays were performed to validate HMGA1 as a target of miR-214. Effect of altering the expression of miR-214 or HMGA1 on proliferation, migration and invasion of human cervical and colorectal cancer cells was investigated.

Results:

miR-214 expression was poor while that of HMGA1 was high in cervical and colorectal cancer tissues. miR-214-re-expression or HMGA1 downregulation inhibited proliferation, migration and invasion of cancer cells while miR-214 inhibition had opposite effects. miR-214 was demonstrated to bind to the wild-type 3′ untranslated region of HMGA1 but not with its mutant.

Conclusions:

Low expression of miR-214 concurrent with elevated levels of HMGA1 may contribute to cervical and colorectal cancer progression. miR-214-mediated regulation of HMGA1 is a novel mechanism for its tumour-suppressive actions in human cervical and colorectal cancer cells and opens up avenues for novel therapeutic strategies for these two cancers.

Downregulation of HMGB1 by miR-34a is sufficient to suppress proliferation, migration and invasion of human cervical and colorectal cancer cells

High mobility group box 1 (HMGB1) is a ubiquitous nuclear protein known to be highly expressed in human cervical (CaCx) and colorectal (CRC) cancers, and sustained high levels of HMGB1 contribute to tumourigenesis and metastasis. HMGB1-targeted cancer therapy is of recent interest, and there are not many studies on miRNA-mediated HMGB1 regulation in these cancers. Since miRNA-based therapeutics for cancer is gaining importance in recent years, it was of interest to predict miRNAs targeting HMGB1. Based on the identification of a potential miR-34a response element in HMGB1-3' untranslated region (3'UTR) and an inverse correlation between HMGB1 and miR-34a expression levels in CaCx and CRC tissues, from a subset of the local population as well as a large sampling from TCGA database, experiments were performed to validate HMGB1 as a direct target of miR-34a in CaCx and CRC cells. Ectopic expression of miR-34a decreased the wild-type HMGB1-3'UTR luciferase activity but not that of its mutant in 3'UTR luciferase assays. While forced expression of miR-34a in CaCx and CRC cells inhibited HMGB1 mRNA and protein levels, proliferation, migration and invasion, inhibition of endogenous miR-34a enhanced these tumourigenic properties. siRNA-mediated HMGB1 suppression imitated miR-34a expression in reducing proliferation and metastasis-related events. Combined with the disparity in expression of miR-34a and HMGB1 in clinical specimens, the current findings would help in not only understanding the complexity of miRNA-target regulatory mechanisms but also in designing novel therapeutic interventions in CaCx and CRC.

MicroRNA-130b improves renal tubulointerstitial fibrosis via repression of Snail-induced epithelial-mesenchymal transition in diabetic nephropathy

MicroRNA-130b (miR-130b) downregulation has been identified in diabetes, but the role and mechanisms for miR-130b in mediating renal tubulointerstitial fibrosis in diabetic nephropathy (DN) remain unknown. We demonstrated that plasma miR-130b downregulation exhibited clinical and biological relevance as it was linked to increased serum creatinine, β2-microglobulin and proteinuria, increased Snail expression and tubulointerstitial fibrosis in renal biopsies of DN patients. MiR-130b inhibitor caused Snail upregulation and enhanced molecular features of epithelial-to-mesenchymal transition (EMT) in high glucose (30 mM) cultured NRK-52E cells. In contrast, miR-130b mimic downregulated Snail expression and increased epithelial hallmarks. Notably, Snail was identified as an miR-130b direct target and inversely correlated with E-CADHERIN expression. Furthermore, the miR-130b-dependent effects were due to Snail suppression that in turn deregulated E-CADHERIN, VIMENTIN, COLLAGEN IV and α-smooth muscle actin (α-SMA), key mediators of EMT. These effects were reproduced in streptozotocin-induced diabetic rats. Thus, we propose a novel role of the miR-130b-SNAIL axis in fostering EMT and progression toward increased tubulointerstitial fibrosis in DN. Detection of plasma miR-130b and its association with SNAIL can be extrapolated to quantifying the severity of renal tubulointerstitial fibrosis. Targeting miR-130b could be evaluated as a potential therapeutic approach for DN.

Mast Cell Proteases 6 and 7 Stimulate Angiogenesis by Inducing Endothelial Cells to Release Angiogenic Factors

Mast cell proteases are thought to be involved with tumor progression and neo-vascularization. However, their exact role is still unclear. The present study was undertaken to further elucidate the function of specific subtypes of recombinant mouse mast cell proteases (rmMCP-6 and 7) in neo-vascularization. SVEC4-10 cells were cultured on Geltrex^® with either rmMCP-6 or 7 and tube formation was analyzed by fluorescence microscopy and scanning electron microscopy. Additionally, the capacity of these proteases to induce the release of angiogenic factors and pro and anti-angiogenic proteins was analyzed. Both rmMCP-6 and 7 were able to stimulate tube formation. Scanning electron microscopy showed that incubation with the proteases induced SVEC4-10 cells to invade the gel matrix. However, the expression and activity of metalloproteases were not altered by incubation with the mast cell proteases. Furthermore, rmMCP-6 and rmMCP-7 were able to induce the differential release of angiogenic factors from the SVEC4-10 cells. rmMCP-7 was more efficient in stimulating tube formation and release of angiogenic factors than rmMCP-6. These results suggest that the subtypes of proteases released by mast cells may influence endothelial cells during in vivo neo-vascularization.

MicroRNA-100 suppresses the migration and invasion of breast cancer cells by targeting FZD-8 and inhibiting Wnt/β-catenin signaling pathway

Wnt/β-catenin signaling pathway plays a major role in the cancer metastasis. Several microRNAs (miRNAs) are contributed to the inhibition of breast cancer metastasis. Here, we attempted to find novel targets and mechanisms of microRNA-100 (miR-100) in regulating the migration and invasion of breast cancer cells. In this study, we found that miR-100 expression was downregulated in human breast cancer tissues and cell lines. The overexpression of miR-100 inhibited the migration and invasion of MDA-MB-231 breast cancer cells. Inversely, the downregulation of miR-100 increased the migration and invasion of MCF-7 breast cancer cells. Furthermore, FZD-8, a receptor of Wnt/β-catenin signaling pathway, was demonstrated a direct target of miR-100. The overexpression of miR-100 decreased the expression levels not only FZD-8 but also the key components of Wnt/β-catenin pathway, including β-catenin, metalloproteniase-7 (MMP-7), T-cell factor-4 (TCF-4), and lymphoid enhancing factor-1 (LEF-1), and increased the protein expression levels of GSK-3β and p-GSK-3β in MDA-MB-231 cells, and the transfection of miR-100 inhibitor in MCF-7 cells showed the opposite effects. In addition, the expression of miR-100 was negatively correlated with the FZD-8 expression in human breast cancer tissues. Overall, these findings suggest that miR-100 suppresses the migration and invasion of breast cancer cells by targeting FZD-8 and inhibiting Wnt/β-catenin signaling pathway and manipulation of miR-100 may provide a promoting therapeutic strategy for cancer breast treatment.

microRNA regulation of Wnt signaling pathways in development and disease

Wnt signaling pathways and microRNAs (miRNAs) are critical regulators of development. Aberrant Wnt signaling pathways and miRNA levels lead to developmental defects and diverse human pathologies including but not limited to cancer. Wnt signaling pathways regulate a plethora of cellular processes during embryonic development and maintain homeostasis of adult tissues. A majority of Wnt signaling components are regulated by miRNAs which are small noncoding RNAs that are expressed in both animals and plants. In animal cells, miRNAs fine tune gene expression by pairing primarily to the 3'untranslated region of protein coding mRNAs to repress target mRNA translation and/or induce target degradation. miRNA-mediated regulation of signaling transduction pathways is important in modulating dose-sensitive response of cells to signaling molecules. This review discusses components of the Wnt signaling pathways that are regulated by miRNAs in the context of development and diseases. A fundamental understanding of miRNA functions in Wnt signaling transduction pathways may yield new insight into crosstalks of regulatory mechanisms essential for development and disease pathophysiology leading to novel therapeutics.

Downregulated miR-495 [Corrected] Inhibits the G1-S Phase Transition by Targeting Bmi-1 in Breast Cancer

Bmi-1 (B cell-specific Moloney murine leukemia virus integration site 1) is upregulated in breast cancer and was involved in many malignant progressions of breast cells, including cell proliferation, stem cell pluripotency, and cancer initiation. However, the epigenetic regulatory mechanism of Bmi-1 in breast cancer remains unclear. After analysis of the ArrayExpress dataset GSE45666, we comparatively detected the expression levels of miR-495 in 9 examined breast cancer cell lines, normal breast epithelial cells and 8 pairs of fresh clinical tumor samples. Furthermore, to evaluate the effect of miR-495 on the progression of breast cancer, MCF-7 and MDA-MB-231 were transduced to stably overexpress miR-495. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, colony formation assays, 5-Bromo-2-deoxyUridine labeling and immunofluorescence, anchorage-independent growth ability assay, flow cytometry analysis, and luciferase assays were used to test the effect of miR-495 in MCF-7 and MDA-MB-231 cells in vitro. Xenografted tumor model was also used to evaluate the effect of miR-495 in breast cancer. Herein, we found that miR-495, a predicted regulator of Bmi-1, was frequently downregulated in malignant cells and tissues of breast. Upregulation of miR-495 significantly suppressed breast cancer cell proliferation and tumorigenicity via G1-S arrest. Further analysis revealed that miR-495 targeted Bmi-1 through its 3' untranslated region. Moreover, Bmi-1 could neutralize the suppressive effect of miR-495 on cell proliferation and tumorigenicity of breast cancer in vivo. These data suggested that miR-495 could inhibit the G1-S phase transition that leads to proliferation and tumorigenicity inhibition by targeting and suppressing Bmi-1 in breast cancer.