Myocyte enhancer factor 2C regulation of hepatocellular carcinoma via vascular endothelial growth factor and Wnt/β-catenin signaling

Cancer-associated fibroblasts: heterogeneity, tumorigenicity and therapeutic targets

Cancer, characterized by its immune evasion, active metabolism, and heightened proliferation, comprises both stroma and cells. Although the research has always focused on parenchymal cells, the non-parenchymal components must not be overlooked. Targeting cancer parenchymal cells has proven to be a formidable challenge, yielding limited success on a broad scale. The tumor microenvironment(TME), a critical niche for cancer cell survival, presents a novel way for cancer treatment. Cancer-associated fibroblast (CAF), as a main component of TME, is a dynamically evolving, dual-functioning stromal cell. Furthermore, their biological activities span the entire spectrum of tumor development, metastasis, drug resistance, and prognosis. A thorough understanding of CAFs functions and therapeutic advances holds significant clinical implications. In this review, we underscore the heterogeneity of CAFs by elaborating on their origins, types and function. Most importantly, by elucidating the direct or indirect crosstalk between CAFs and immune cells, the extracellular matrix, and cancer cells, we emphasize the tumorigenicity of CAFs in cancer. Finally, we highlight the challenges encountered in the exploration of CAFs and list targeted therapies for CAF, which have implications for clinical treatment.

Computational insights into irinotecan's interaction with UBE2I in ovarian and endometrial cancers

Endometrial and Ovarian cancers are two highly prevalent and fatal reproductive diseases with poor prognoses among women. Elevated estrogen levels in Ovarian Cancer (OC) stimulate the endometrium, causing Endometrial Cancer (EC). Although numerous studies have reported the crucial genes and pathways in this cancer, the pathogenesis of this disease remains unclear. In this study, used bioinformatics tools to analyse GSE63678, GSE115810, GSE36389, GSE26712, GSE36668, GSE27651, GSE6008, GSE69429, GSE69428, GSE18521, GSE185209, GSE54388 gene expression microarray datasets for both the cancers. We analyzed the differential gene expression, functional association, and structural studies. The analysis identified crucial differentially expressed genes (DEGs) in both cancers associated with DNA damage, DNA integrity, and cell-cycle checkpoint signaling pathways. CLDN7, UBE2I, WT1, JAM2, FOXL2, F11R, JAM3, ZFPM2, MEF2C, and PIAS1 are the top 10 hub genes commonly identified in both cancer types. Only CLDN7 and F11R are upregulated, whereas the remaining hub genes are downregulated in both cancers, suggesting a common framework for contributing to tumorigenesis. Molecular docking and dynamics were performed on the UBE2I protein with Irinotecan Hydrochloride, which could serve as the new approach for treating and managing both cancers. The study reveals the common molecular pathways, pointing out the role of cell cycle and DNA damage and integrity checkpoint signaling in the pathogenesis of both cancer types. This study explored the UBE2I gene as a potential biomarker in OC and EC. Further, this study concludes that the irinotecan hydrochloride drug has higher therapeutic effects on UBE2I protein through docking and dynamics studies.

CD74+ fibroblasts proliferate upon mechanical stretching to promote angiogenesis in keloids

The healing of human skin wounds is susceptible to perturbation caused by excessive mechanical stretching, resulting in enlarged scars, hypertrophic scars, or even keloids in predisposed individuals. Keloids are fibro-proliferative scar tissues that extend beyond the initial wound boundary, consisting of the actively progressing periphery and the quiescent center. The stretch-associated outgrowth and enhanced angiogenesis are two features of the periphery of keloids. However, which cell population is responsible for transducing the mechanical stimulation to the progression of keloids remains unclear. Herein, through integrative analysis of single-cell RNA sequencing of keloids, we identified CD74+ fibroblasts, a previously unappreciated subset of fibroblasts with pro-angiogenic and stretch-induced proliferative capacities, as a key player in stretch-induced progression of keloids. Immunostaining of keloid cryosections depicted a predominant distribution of CD74+ fibroblasts in the periphery, interacting with the vasculature. In vitro tube formation assays on purified CD74+ fibroblasts ascertained their pro-angiogenic function. BrdU assays revealed that these cells proliferate upon stretching, through PIEZO1-mediated calcium influx and the downstream ERK and AKT signaling. Collectively, our findings propose a model wherein CD74+ fibroblasts serve as pivotal drivers of stretch-induced keloid progression, fueled by their proliferative and pro-angiogenic activities. Targeting the attributes of CD74+ fibroblasts holds promise as a therapeutic strategy for the management of keloids.

Mechanisms of angiogenesis in tumour

Angiogenesis is essential for tumour growth and metastasis. Antiangiogenic factor-targeting drugs have been approved as first line agents in a variety of oncology treatments. Clinical drugs frequently target the VEGF signalling pathway during sprouting angiogenesis. Accumulating evidence suggests that tumours can evade antiangiogenic therapy through other angiogenesis mechanisms in addition to the vascular sprouting mechanism involving endothelial cells. These mechanisms include (1) sprouting angiogenesis, (2) vasculogenic mimicry, (3) vessel intussusception, (4) vascular co-option, (5) cancer stem cell-derived angiogenesis, and (6) bone marrow-derived angiogenesis. Other non-sprouting angiogenic mechanisms are not entirely dependent on the VEGF signalling pathway. In clinical practice, the conversion of vascular mechanisms is closely related to the enhancement of tumour drug resistance, which often leads to clinical treatment failure. This article summarizes recent studies on six processes of tumour angiogenesis and provides suggestions for developing more effective techniques to improve the efficacy of antiangiogenic treatment.

Inference of differential gene regulatory networks using boosted differential trees

Summary

Diseases can be caused by molecular perturbations that induce specific changes in regulatory interactions and their coordinated expression, also referred to as network rewiring. However, the detection of complex changes in regulatory connections remains a challenging task and would benefit from the development of novel nonparametric approaches. We develop a new ensemble method called BoostDiff (boosted differential regression trees) to infer a differential network discriminating between two conditions. BoostDiff builds an adaptively boosted (AdaBoost) ensemble of differential trees with respect to a target condition. To build the differential trees, we propose differential variance improvement as a novel splitting criterion. Variable importance measures derived from the resulting models are used to reflect changes in gene expression predictability and to build the output differential networks. BoostDiff outperforms existing differential network methods on simulated data evaluated in four different complexity settings. We then demonstrate the power of our approach when applied to real transcriptomics data in COVID-19, Crohn's disease, breast cancer, prostate adenocarcinoma, and stress response in Bacillus subtilis. BoostDiff identifies context-specific networks that are enriched with genes of known disease-relevant pathways and complements standard differential expression analyses.

Availability and implementation

BoostDiff is available at https://github.com/scibiome/boostdiff_inference.

Cancer stem cells and angiogenesis

Cancer remains the primary cause of mortality in developed nations. Although localized tumors can be effectively addressed through surgery, radiotherapy, and other targeted methods, drug efficacy often wanes in the context of metastatic diseases. As a result, significant efforts are being made to develop drugs capable of not only inhibiting tumor growth but also impeding the metastasis of malignant tumors, with a focus on hindering their migration to adjacent organs. Cancer stem cells metastasize via blood and lymphatic vessels, exhibiting a high mutation rate, significant variability, and a predisposition to drug resistance. In contrast, endothelial cells, being less prone to mutation, are less likely to give rise to drug-resistant clones. Furthermore, the direct contact of circulating anti-angiogenic drugs with vascular endothelial cells expedites their therapeutic impact. Hence, anti-angiogenesis targeted therapy assumes a pivotal role in cancer treatment. This paper provides a succinct overview of the molecular mechanisms governing the interaction between cancer stem cells and angiogenesis.

Effects of RNA methylation on Tumor angiogenesis and cancer progression

Tumor angiogenesis plays vital roles in the growth and metastasis of cancer. RNA methylation is one of the most common modifications and is widely observed in eukaryotes and prokaryotes. Accumulating studies have revealed that RNA methylation affects the occurrence and development of various tumors. In recent years, RNA methylation has been shown to play an important role in regulating tumor angiogenesis. In this review, we mainly elucidate the mechanisms and functions of RNA methylation on angiogenesis and progression in several cancers. We then shed light on the role of RNA methylation-associated factors and pathways in tumor angiogenesis. Finally, we describe the role of RNA methylation as potential biomarker and novel therapeutic target.

The molecular classification of cancer-associated fibroblasts on a pan-cancer single-cell transcriptional atlas

BACKGROUND

Cancer-associated fibroblasts (CAFs), integral to the tumour microenvironment, are pivotal in cancer progression, exhibiting either pro-tumourigenic or anti-tumourigenic functions. Their inherent phenotypic and functional diversity allows for the subdivision of CAFs into various subpopulations. While several classification systems have been suggested for different cancer types, a unified molecular classification of CAFs on a single-cell pan-cancer scale has yet to be established.

METHODS

We employed a comprehensive single-cell transcriptomic atlas encompassing 12 solid tumour types. Our objective was to establish a novel molecular classification and to elucidate the evolutionary trajectories of CAFs. We investigated the functional profiles of each CAF subtype using Single-Cell Regulatory Network Inference and Clustering and single-cell gene set enrichment analysis. The clinical relevance of these subtypes was assessed through survival curve analysis. Concurrently, we employed multiplex immunofluorescence staining on tumour tissues to determine the dynamic changes of CAF subtypes across different tumour stages. Additionally, we identified the small molecule procyanidin C1 (PCC1) as a target for matrix-producing CAF (matCAF) using molecular docking techniques and further validated these findings through in vitro and in vivo experiments.

RESULTS

In our investigation of solid tumours, we identified four molecular clusters of CAFs: progenitor CAF (proCAF), inflammatory CAF (iCAF), myofibroblastic CAF (myCAF) and matCAF, each characterised by distinct molecular traits. This classification was consistently applicable across all nine studied solid tumour types. These CAF subtypes displayed unique evolutionary pathways, functional roles and clinical relevance in various solid tumours. Notably, the matCAF subtype was associated with poorer prognoses in several cancer types. The targeting of matCAF using the identified small molecule, PCC1, demonstrated promising antitumour activity.

CONCLUSIONS

Collectively, the various subtypes of CAFs, particularly matCAF, are crucial in the initiation and progression of cancer. Focusing therapeutic strategies on targeting matCAF in solid tumours holds significant potential for cancer treatment.

Machine-learning based integrating bulk and single-cell RNA sequencing reveals the SLC38A5-CCL5 signaling as a promising target for clear cell renal cell carcinoma treatment

Cancer-associated fibroblasts paly critical roles in regulating cancer cell biological properties by intricate and dynamic communication networks. But the mechanism of CAFs in clear cell renal cell carcinoma (ccRCC) is not clear. In our study, we identified CAFs and malignant cells from the integrated scRNA-seq datasets and establish a CAF-derived communication signature based on the highly activated regulons ETS1 and MEF2C. We stratified the ccRCC TME into two molecular subtypes with distinct prognoses, immune cell infiltration landscapes, and immune-related characteristics. The model derived from signature demonstrated high accuracy and robustness in predicting prognosis and ICIs therapy responses. Subsequently, the SLC38A5 of the model was found upregulated in CAFs and was related to decreased survival probabilities, inflamed TME, and upregulated inhibitory checkpoints. SLC38A5 inhibition could attenuate the pro-tumoral abilities of CAFs in terms of proliferation, migration, and invasion. Mechanically, CCL5 could restore these properties induced by SLC38A5 inhibition. In conclusion, our communication signature and its derived model enabled a more precise selection of ccRCC patients who were potential beneficiaries of ICIs. Besides, the SLC38A5-CCL5 axis may serve as a promising target for ccRCC treatment.

MEF2C and miR-194-5p: New Players in Triple Negative Breast Cancer Tumorigenesis

Among breast cancer (BC) subtypes, the most aggressive is triple negative BC (TNBC), which is prone to metastasis. We previously found that microRNA (miR)-194-5p is downregulated at the early stages of TNBC brain metastasis development. Additionally, the transcription factor myocyte enhancer factor 2 (MEF2)C, a bioinformatically predicted miR-194-5p target, was increasingly expressed throughout TNBC brain metastasis formation and disease severity. However, the contributions of these two players to malignant cells' features remain undetermined. This study aimed at disclosing the role of miR-194-5p and MEF2C in TNBC tumorigenesis. The transfection of 4T1 cells with a silencer for MEF2C or with a pre-miRNA for miR-194-5p was employed to study TNBC cells' phenotypic alterations regarding epithelial and mesenchymal markers, as well as migratory capability alterations. MEF2C-silenced cells presented a decline in both vimentin and cytokeratin expression, whereas the overexpression of miR-194-5p promoted an increase in cytokeratin and a reduction in vimentin, reflecting the acquisition of an epithelial phenotype. Both treatments reduced TNBC cells' migration. These results suggest that MEF2C may determine TNBC cells' invasive properties by partially determining the occurrence of epithelial-mesenchymal transition, while the overexpression of miR-194-5p promotes a decline in TNBC cells' aggressive behavior and reinforces this miRNA's role as a tumor suppressor in TNBC.

Live-cell imaging-based dynamic vascular formation assay for antivascular drug evaluation and screening

New vessel formation (angiogenesis) is an essential physiological process for embryologic development, normal growth, and tissue repair. Angiogenesis is tightly regulated at the molecular level. Dysregulation of angiogenesis occurs in various pathologies and is one of the hallmarks of cancer. However, most existing methods for evaluating cell vascular formation are limited to static analysis and prone to bias due to time, field of vision, and parameter selection. Code scripts, such as AngiogenesisAnalyzer.ijm, AutomaticMeasure.ijm, and VM.R., were developed to study the dynamic angiogenesis process. This method was used to screen drugs that could affect the time, maximum value, tilt, and decline rate of cell vascular formation and angiogenesis. Animal experiments have confirmed that these drugs could inhibit the formation of blood vessels. This work provides a new perspective for the research of angiogenesis process and is helpful to the development of drugs related to angiogenesis.

USP22 upregulates ZEB1-mediated VEGFA transcription in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common solid tumor with high rate of recurrence and mortality. Anti-angiogenesis drugs have been used for the therapy of HCC. However, anti-angiogenic drug resistance commonly occurs during HCC treatment. Thus, identification of a novel VEGFA regulator would be better understanding for HCC progression and anti-angiogenic therapy resistance. Ubiquitin specific protease 22 (USP22) as a deubiquitinating enzyme, participates in a variety of biological processes in numerous tumors. While the molecular mechanism underlying the effects of USP22 on angiogenesis is still needed to be clarified. Here, our results demonstrated that USP22 acts as a co-activator of VEGFA transcription. Importantly, USP22 is involved in maintenance of ZEB1 stability via its deubiquitinase activity. USP22 was recruited to ZEB1-binding elements on the promoter of VEGFA, thereby altering histone H2Bub levels, to enhance ZEB1-mediated VEGFA transcription. USP22 depletion decreased cell proliferation, migration, Vascular Mimicry (VM) formation, and angiogenesis. Furthermore, we provided the evidence to show that knockdown of USP22 inhibited HCC growth in tumor-bearing nude mice. In addition, the expression of USP22 is positively correlated with that of ZEB1 in clinical HCC samples. Our findings suggest that USP22 participates in the promotion of HCC progression, if not all, at least partially via up-regulation of VEGFA transcription, providing a novel therapeutic target for anti-angiogenic drug resistance in HCC.

A Diagnostic Model Using Exosomal Genes for Colorectal Cancer

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. Exosomes have great potential as liquid biopsy specimens due to their presence and stability in body fluids. However, the function and diagnostic values of exosomal genes in CRC are poorly understood. In the present study, exosomal data of CRC and healthy samples from the exoRBase 2.0 and Gene Expression Omnibus (GEO) databases were used, and 38 common exosomal genes were identified. Through the least absolute shrinkage and selection operator (Lasso) analysis, support vector machine recursive feature elimination (SVM-RFE) analysis, and logistic regression analysis, a diagnostic model of the training set was constructed based on 6 exosomal genes. The diagnostic model was internally validated in the test and exoRBase 2.0 database and externally validated in the GEO database. In addition, the co-expression analysis was used to cluster co-expression modules, and the enrichment analysis was performed on module genes. Then a protein–protein interaction and competing endogenous RNA network were constructed and 10 hub genes were identified using module genes. In conclusion, the results provided a comprehensive understanding of the functions of exosomal genes in CRC as well as a diagnostic model related to exosomal genes.

Progress on the roles of MEF2C in neuropsychiatric diseases

Myocyte Enhancer Factor 2 C (MEF2C), one of the transcription factors of the MADS-BOX family, is involved in embryonic brain development, neuronal formation and differentiation, as well as in the growth and pruning of axons and dendrites. MEF2C is also involved in the development of various neuropsychiatric disorders, such as autism spectrum disorders (ASD), epilepsy, schizophrenia and Alzheimer’s disease (AD). Here, we review the relationship between MEF2C and neuropsychiatric disorders, and provide further insights into the mechanism of these diseases.

MicroRNA‑190b expression predicts a good prognosis and attenuates the malignant progression of pancreatic cancer by targeting MEF2C and TCF4

MicroRNAs (miRNAs/miRs) are key components of regulatory networks in cancer. Although miR-190b is an important tumor-related miRNA, its role in pancreatic cancer has not been extensively investigated. The aim of the present study was to examine the expression of miR-190b in pancreatic cancer cell lines and tissues and evaluate its effects on cancer progression. Reverse transcription-quantitative PCR (RT-qPCR) analysis was used to measure miR-190b expression levels in human pancreatic cancer cell lines and tissues, and the association between miR-190b expression and clinicopathological characteristics was assessed. An in vitro Transwell invasion assay and an in vivo metastasis formation assay were performed using pancreatic cancer cells. The effect of miR-190b on pancreatic cancer cell proliferation was evaluated using a Cell Counting Kit-8 assay based on an in vivo xenograft mouse model. The direct targets of miR-190b were predicted using bioinformatics tools and were validated through western blotting and luciferase reporter assays. Pancreatic cancer cell lines and tissues were found to express lower levels of miR-190b compared with normal cells and adjacent non-tumor tissues. Furthermore, high expression of miR-190b was found to be positively correlated with low T, N and American Joint Committee on Cancer classifications, and predicted a good prognosis. miR-190b was shown to exert suppressive effects on cancer cell proliferation, invasion and metastasis. In addition, it was also found that miR-190b directly targeted myocyte enhancer factor 2C (MEF2C) and transcription factor 4 (TCF4) in pancreatic cancer, thus serving as a tumor suppressor and a predictor of good prognosis in pancreatic cancer. The immunohistochemistry and RT-qPCR results indicated that the MEF2C and TCF4 expression levels were negatively correlated with the miR-190b expression levels. The findings of the present study highlight the value of miR-190b as a novel target candidate for pancreatic cancer diagnosis and therapy.

A Novel Overall Survival Prediction Signature Based on Cancer Stem Cell-Related Genes in Osteosarcoma

Background: Osteosarcoma is the most general bone malignancy that mostly affects children and adolescents. Numerous stem cell-related genes have been founded in distinct forms of cancer. This study aimed at identifying a stem cell-related gene model for the expected assessment of the prognosis of osteosarcoma patients.

Methods: We obtained the genes expression data and relevant clinical materials from Therapeutically Applicable Research to Generate Effective Treatments (TARGET) and Gene Expression Omnibus (GEO) databases. We identified differentially expressed genes (DEGs) from the GEO dataset, whereas prognostic stem cell-related genes were obtained from the TARGET database. Subsequently, univariate, LASSO and multivariate Cox regression analyses were applied to establish the stem cell-related signature. Finally, the prognostic value of the signature was validated in the GEO dataset.

Results: Twenty-five genes were prognostic ferroptosis-related DEGs. Consequently, we identified eight stem cell-related genes as a signature of prognosis of osteosarcoma patients. Then, the Kaplan–Meier (K-M) curve, the AUC value of ROC, and Cox regression analysis verified that the eight stem cell-related gene model were a new and substantial prognostic marker independent of other clinical traits. Moreover, the nomogram on the foundation of risk score and other clinical traits was established for predicting the survival rate of osteosarcoma patients. Biological function analyses displayed that tumor related pathways were affluent.

Conclusion: The expression level of stem cell-related genes offers novel prognostic markers as well as underlying therapeutic targets for the therapy and prevention of osteosarcoma.

MEF2C silencing downregulates NF2 and E-cadherin and enhances Erastin-induced ferroptosis in meningioma

BACKGROUND

Ferroptosis, a programmed cell death characterized by lipid peroxidation, is implicated in various diseases including cancer. Although cell density-dependent E-cadherin and Merlin/Neurofibromin (NF2) loss can modulate ferroptosis, the role of ferroptosis and its potential link to NF2 status and E-cadherin expression in meningioma remain unknown.

METHODS

Relationship between ferroptosis modulators expression and NF2 mutational status was examined in 35 meningiomas (10 NF2 loss and 25 NF2 wildtype). The impact of NF2 and E-cadherin on ferroptosis were examined by LDH release, lipid peroxidation and western blot assays in IOMM-Lee, CH157 and patient-derived meningioma cell models. Luciferase reporter and chromatin immunoprecipitation assays were used to assess the ability of MEF2C (myocyte enhancer factor 2C) to drive expression of NF2 and CDH1 (E-cadherin). Therapeutic efficacy of Erastin-induced ferroptosis was tested in xenograft mouse models.

RESULTS

Meningioma cells with NF2 inactivation were susceptible to Erastin-induced ferroptosis. Meningioma cells grown at higher density increased expression of E-Cadherin, which suppressed Erastin-induced ferroptosis. Maintaining NF2 and E-cadherin inhibited ferroptosis-related lipid peroxidation and meningioma cell death. MEF2C was found to drive the expression of both NF2 and E-cadherin. MEF2C silencing enhanced Erastin-induced ferroptotic meningioma cell death and lipid peroxidation levels in vitro, which was limited by forced expression of MEF2C targets, NF2 and E-Cadherin. In vivo, anti-meningioma effect of Erastin was augmented by MEF2C knockdown and was counteracted by NF2 or E-Cadherin.

CONCLUSIONS

NF2 loss and low E-cadherin create susceptibility to ferroptosis in meningioma. MEF2C could be a new molecular target in ferroptosis-inducing therapies for meningioma.

Regulatory mechanisms and therapeutic targeting of vasculogenic mimicry in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a typical hyper-vascular solid tumor; aberrantly rich in tumor vascular network contributes to its malignancy. Conventional anti-angiogenic therapies seem promising but transitory and incomplete efficacy on HCC. Vasculogenic mimicry (VM) is one of functional microcirculation patterns independent of endothelial vessels which describes the plasticity of highly aggressive tumor cells to form vasculogenic-like networks providing sufficient blood supply for tumor growth and metastasis. As a pivotal alternative mechanism for tumor vascularization when tumor cells undergo lack of oxygen and nutrients, VM has an association with the malignant phenotype and poor clinical outcome for HCC, and may challenge the classic anti-angiogenic treatment of HCC. Current studies have contributed numerous findings illustrating the underlying molecular mechanisms and signaling pathways supporting VM in HCC. In this review, we summarize the correlation between epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) and VM, the role of hypoxia and extracellular matrix remodeling in VM, the involvement of adjacent non-cancerous cells, cytokines and growth factors in VM, as well as the regulatory influence of non-coding RNAs on VM in HCC. Moreover, we discuss the clinical significance of VM in practice and the potential therapeutic strategies targeting VM for HCC. A better understanding of the mechanism underlying VM formation in HCC may optimize anti-angiogenic treatment modalities for HCC.

Myocyte Enhancer Factor 2C as a New Player in Human Breast Cancer Brain Metastases

Myocyte enhancer factor 2C (MEF2C) is increasingly expressed in mice along with breast cancer brain metastases (BCBM) development. We aim to ascertain MEF2C expression in human BCBM, establish the relationship with disease severity, disclose the involvement of vascular endothelial growth factor receptor-2 (VEGFR-2) and β-catenin, also known as KDR and CTNNB1, respectively, and investigate if matched primary tumors express the protein. We studied resected BCBM for the expression of MEF2C, VEGFR-2, and ß-catenin, as well as proliferation (Ki-67) and epithelial (pan Cytokeratin) markers, and related experimental and clinical data. MEF2C expression was further assessed in matched primary tumors and non-BCBM samples used as controls. MEF2C expression was observed in BCBM, but not in controls, and was categorized into three phenotypes (P): P1, with extranuclear location; P2, with extranuclear and nuclear staining, and P3, with nuclear location. Nuclear translocation increased with metastases extension and Ki-67-positive cells number. P1 was associated with higher VEFGR-2 plasma membrane immunoreactivity, whereas P2 and P3 were accompanied by protein dislocation. P1 was accompanied by β-catenin membrane expression, while P2 and P3 exhibited β-catenin nuclear translocation. Primary BC samples expressed MEF2C in mammary ducts and scattered cells in the parenchyma. MEF2C emerges as a player in BCBM associated with disease severity and VEGFR-2 and β-catenin signaling.

PATZ1 (MAZR) Co-occupies Genomic Sites With p53 and Inhibits Liver Cancer Cell Proliferation via Regulating p27

Liver cancer is the third most common cause of cancer death in the world. POZ/BTB and AT-hook-containing zinc finger protein 1 (PATZ1/MAZR) is a transcription factor associated with various cancers. However, the role of PATZ1 in cancer progression remains controversial largely due to lack of genome-wide studies. Here we report that PATZ1 regulates cell proliferation by directly regulating CDKN1B (p27) in hepatocellular carcinoma cells. Our PATZ1 ChIP-seq and gene expression microarray analyses revealed that PATZ1 is strongly related to cancer signatures and cellular proliferation. We further discovered that PATZ1 depletion led to an increased rate of colony formation, elevated Ki-67 expression and greater S phase entry. Importantly, the increased cancer cell proliferation was accompanied with suppressed expression of the cyclin-dependent kinase inhibitor CDKN1B. Consistently, we found that PATZ1 binds to the genomic loci flanking the transcriptional start site of CDKN1B and positively regulates its transcription. Notably, we demonstrated that PATZ1 is a p53 partner and p53 is essential for CDKN1B regulation. In conclusion, our study provides novel mechanistic insights into the inhibitory role of PATZ1 in liver cancer progression, thereby yielding a promising therapeutic intervention to alleviate tumor burden.

RNA m6A methylation promotes the formation of vasculogenic mimicry in hepatocellular carcinoma via Hippo pathway

Vasculogenic mimicry (VM) formed by aggressive tumor cells to mimic vasculogenic networks plays an important role in the tumor malignancy of HCC. However, the pathogenesis underlying VM is complex and has not been fully defined. m6A is a common mRNA modification and has many biological effects. However, the relationship between m6A and VM remains unclear. In this research, we found that m6A methyltransferase METTL3 in HCC tissues was positively correlated with VM. The m6A level of mRNA significantly increased in 3D cultured cells treated with VEGFa and was related to VM formation. Transcriptome sequencing analysis of 3D cultured cells with knockdown Mettl3 showed that the Hippo pathway was involved in m6A-mediated VM formation. Further mechanism research indicated that the m6A modification of YAP1 mRNA affected the translation of YAP1 mRNA. In conclusion, m6A methylation plays a key role in VM formation in HCC. METTL3 and YAP1 could be potential therapeutic targets via impairing VM formation in anti-metastatic strategies.

MEF2A transcriptionally upregulates the expression of ZEB2 and CTNNB1 in colorectal cancer to promote tumor progression

Colorectal cancer (CRC) is one of the leading cancers worldwide, accounting for high morbidity and mortality. The mechanisms governing tumor growth and metastasis in CRC require detailed investigation. The results of the present study indicated that the transcription factor (TF) myocyte enhancer factor 2A (MEF2A) plays a dual role in promoting proliferation and metastasis of CRC by inducing the epithelial-mesenchymal transition (EMT) and activation of WNT/β-catenin signaling. Aberrant expression of MEF2A in CRC clinical specimens was significantly associated with poor prognosis and metastasis. Functionally, MEF2A directly binds to the promoter region to initiate the transcription of ZEB2 and CTNNB1. Simultaneous activation of the expression of EMT-related TFs and Wnt/β-catenin signaling by MEF2A overexpression induced the EMT and increased the frequency of tumor formation and metastasis. The present study identified a new critical oncogene involved in the growth and metastasis of CRC, providing a potential novel therapeutic target for CRC intervention.

Androgen receptor suppresses vasculogenic mimicry in hepatocellular carcinoma via circRNA7/miRNA7-5p/VE-cadherin/Notch4 signalling

Androgen receptor (AR) can suppress hepatocellular carcinoma (HCC) invasion and metastasis at an advanced stage. Vasculogenic mimicry (VM), a new vascularization pattern by which tumour tissues nourish themselves, is correlated with tumour progression and metastasis. Here, we investigated the effect of AR on the formation of VM and its mechanism in HCC. The results suggested that AR could down-regulate circular RNA (circRNA) 7, up-regulate micro RNA (miRNA) 7-5p, and suppress the formation of VM in HCC Small hairpin circR7 (ShcircR7) could reverse the impact on VM and expression of VE-cadherin and Notch4 increased by small interfering AR (shAR) in HCC, while inhibition of miR-7-5p blocked the formation of VM and expression of VE-cadherin and Notch4 decreased by AR overexpression (oeAR) in HCC. Mechanism dissection demonstrated that AR could directly target the circR7 host gene promoter to suppress circR7, and miR-7-5p might directly target the VE-cadherin and Notch4 3'UTR to suppress their expression in HCC. In addition, knockdown of Notch4 and/or VE-cadherin revealed that shVE-cadherin or shNotch4 alone could partially reverse the formation of HCC VM, while shVE-cadherin and shNotch4 together could completely suppress the formation of HCC VM. Those results indicate that AR could suppress the formation of HCC VM by down-regulating circRNA7/miRNA7-5p/VE-Cadherin/Notch4 signals in HCC, which will help in the design of novel therapies against HCC.

Supervillin promotes tumor angiogenesis in liver cancer

Tumor angiogenesis is a hallmark of liver cancer and is necessary for tumor growth and progression. Supervillin (SVIL) is highly expressed and implicated in several malignant processes of liver cancer. However, the functional relationships between SVIL and tumor angiogenesis in liver cancer have not yet been fully elucidated. The present study was based on bioinformatics analysis, patient tissue sample detection, three-dimensional simulated blood vessel formation, a series of cytological experiments and mouse models. The results demonstrated the important role of SVIL in the progression of malignant liver cancer and tumor angiogenesis, both in terms of vasculogenic mimicry (VM) and endothelium-dependent vessel (EDV) development. SVIL knockdown inhibited VM formation and induced tumor cell apoptosis via the VEGF-p38 signaling axis and through various VM-associated transcriptional factors, including vascular endothelial-cadherin, matrix metalloproteinase 9/12 and migration-inducing protein 7. SVIL may therefore be considered a potential tumor vascular biomarker and a promising therapeutic target for patients with liver cancer.

Methylation‑associated silencing of miR‑638 promotes endometrial carcinoma progression by targeting MEF2C

Promoter methylation‑associated silencing of cancer‑associated microRNAs (miRNAs) is a common epigenetic mechanism during tumorigenesis in various types of human cancer. However, this has not been comprehensively examined in endometrial carcinoma (EC). In the present study, an miRNA microarray consisting of 1,347 common human miRNAs was used to select potential tumor suppressive miRNAs that were hyper‑methylated in EC. This led to the identification of miR‑638, miR‑210 and miR‑3665. The methylation status of miR‑638 was examined by bisulfite sequencing polymerase chain reaction and miR‑638 expression was measured by TaqMan miRNA assays. EC cell lines transfected with vectors overexpressing miR‑638, its target gene myocyte enhancer factor 2C (MEF2C) or both, were constructed. Dual‑luciferase reporter assays, a xenograft mouse model and rescue experiments were designed to study miR‑638 and its target gene MEF2C. The results indicated that the promoter region of miR‑638 was highly methylated and the expression of miR‑638 was significantly downregulated in cancerous tissues from 42 patients with EC who underwent surgical resection. Additionally, a low expression of miR‑638 was significantly associated with advanced Federation of Gynecology and Obstetrics stage and was demonstrated to indicate shorter disease‑free survival. Functional studies indicated that the overexpression of miR‑638 in EC cell lines inhibited in vitro tumor progression and in vivo tumorigenicity. MEF2C was verified as a direct target of miR‑638 and was demonstrated to mediate the tumor‑suppressive function of miR‑638 in EC.

Vasculogenic mimicry in carcinogenesis and clinical applications

Distinct from classical tumor angiogenesis, vasculogenic mimicry (VM) provides a blood supply for tumor cells independent of endothelial cells. VM has two distinct types, namely tubular type and patterned matrix type. VM is associated with high tumor grade, tumor progression, invasion, metastasis, and poor prognosis in patients with malignant tumors. Herein, we discuss the recent studies on the role of VM in tumor progression and the diverse mechanisms and signaling pathways that regulate VM in tumors. Furthermore, we also summarize the latest findings of non-coding RNAs, such as lncRNAs and miRNAs in VM formation. In addition, we review application of molecular imaging technologies in detection of VM in malignant tumors. Increasing evidence suggests that VM is significantly associated with poor overall survival in patients with malignant tumors and could be a potential therapeutic target.

Downregulation of circulating miR 802-5p and miR 194-5p and upregulation of brain MEF2C along breast cancer brain metastasization

Breast cancer brain metastases (BCBMs) have been underinvestigated despite their high incidence and poor outcome. MicroRNAs (miRNAs), and particularly circulating miRNAs, regulate multiple cellular functions, and their deregulation has been reported in different types of cancer and metastasis. However, their signature in plasma along brain metastasis development and their relevant targets remain undetermined. Here, we used a mouse model of BCBM and next‐generation sequencing (NGS) to establish the alterations in circulating miRNAs during brain metastasis formation and development. We further performed bioinformatics analysis to identify their targets with relevance in the metastatic process. We additionally analyzed human resected brain metastasis samples of breast cancer patients for target expression validation. Breast cancer cells were injected in the carotid artery of mice to preferentially induce metastasis in the brain, and samples were collected at different timepoints (5 h, 3, 7, and 10 days) to follow metastasis development in the brain and in peripheral organs. Metastases were detected from 7 days onwards, mainly in the brain. NGS revealed a deregulation of circulating miRNA profile during BCBM progression, rising from 18% at 3 days to 30% at 10 days following malignant cells’ injection. Work was focused on those altered prior to metastasis detection, among which were miR‐802‐5p and miR‐194‐5p, whose downregulation was validated by qPCR. Using targetscan and diana tools, the transcription factor myocyte enhancer factor 2C (MEF2C) was identified as a target for both miRNAs, and its expression was increasingly observed in malignant cells along brain metastasis development. Its upregulation was also observed in peritumoral astrocytes pointing to a role of MEF2C in the crosstalk between tumor cells and astrocytes. MEF2C expression was also observed in human BCBM, validating the observation in mouse. Collectively, downregulation of circulating miR‐802‐5p and miR‐194‐5p appears as a precocious event in BCBM and MEF2C emerges as a new player in brain metastasis development.

Tankyrases/β-catenin Signaling Pathway as an Anti-proliferation and Anti-metastatic Target in Hepatocarcinoma Cell Lines

Objective: The Wnt/β-catenin pathway is involved in the development of hepatocellular carcinoma (HCC) and malignant events such as the epithelial-mesenchymal transition (EMT), metastasis, and invasion. Studies have illustrated that the inhibition of tankyrases (TNKS) antagonizes Wnt/β-catenin signaling in many cancer cells. Methods: The expression levels of proteins related to the Wnt/β-catenin pathway and EMT were analyzed by immunohistochemistry in HCC tissue and paired adjacent normal tissue (n = 10), and in an analysis of The Cancer Genome Atlas (TCGA) data. Additionally, after treatment of HCC cell lines with TNKS1/2 small interfering RNA (siRNA) and a novel TNKS inhibitor (NVP-TNKS656), cell viability, cell clone formation, wound-healing, and cell invasion assays were performed. Results: Higher expression of β-catenin, TNKS, vimentin, and N-cadherin was observed in HCC tissue compared to adjacent normal tissue, but lower expression of E-cadherin was found in HCC tissue. These findings were also observed in the TCGA analysis. In addition, TNKS inhibition (using TNKS1/2 siRNA and NVP-TNKS656) not only abrogated the proliferation of the HCC cell lines but also suppressed metastasis, invasion, and EMT phenotypic features. Moreover, the mechanisms related to TNKS inhibition in HCC probably involved the stabilization of AXIN levels and the downregulation of β-catenin, which mediates EMT marker expression. Conclusion: The TNKS/β-catenin signaling pathway is a potential anti-proliferation and anti-metastatic target in HCC.

Androgen receptor suppresses prostate cancer metastasis but promotes bladder cancer metastasis via differentially altering miRNA525-5p/SLPI-mediated vasculogenic mimicry formation

Early studies suggest that the androgen receptor (AR) may play differential roles in influencing prostate cancer (PCa) and bladder cancer (BCa) metastasis, but the underlying mechanisms remain unclear. Here, we found that the AR might function via differentially altering vasculogenic mimicry (VM) formation to either decrease PCa metastasis or increase BCa metastasis. Mechanism dissection showed that the AR could differentially alter the expression of the VM marker SLPI through miR-525-5p to regulate SLPI; moreover, it could either increase miR-525-5p transcription in PCa or decrease it in BCa via binding to different androgen-response-elements (AREs) located at different positions in the miR-525 precursor promoter. Further, results from liquid chromatography-mass spectrometry (LC-MS) showed that the co-factors of AR in PCa and BCa are NFIX and HDAC2, respectively. Together, these results provide the first detailed mechanism of how the AR can differentially alter PCa and BCa metastasis; thus, targeting the newly identified AR-miR-525-5p-SLPI axis may help suppress metastasis.

miR-190-5p in human diseases

miRNAs, a major class of small noncoding RNAs approximately 18-25 nucleotides in length, function by repressing the expression of target genes through binding to complementary sequences in the 3'-UTRs of target genes. Emerging evidence has highlighted their important roles in numerous diseases, including human cancers. Recently, miR-190 has been shown to be dysregulated in various types of human cancers that participates in cancer-related biological processes, including proliferation, apoptosis, metastasis, drug resistance, by regulating associated target genes, and to predict cancer diagnosis and prognosis. In this review, we summarized the roles of miR-190-5p in human diseases, especially in human cancers. Then we classified its target genes in tumorigenesis and progression, which might provide evidence for cancer diagnosis and prognosis, promising tools for cancer treatment, or leads for further investigation.

Administration of SB239063 Ameliorates Ovariectomy-Induced Bone Loss via Suppressing Osteoclastogenesis in Mice

Activation of osteoclast formation and function is crucial for the development of osteolytic diseases such as osteoporosis. RANKL (receptor activator of nuclear factor-κB ligand) activates NF-κB (nuclear factor κB), MAPK (mitogen-activated protein kinase), and NFATc1 (nuclear factor of activated T-cells, cytoplasmic 1) signaling pathways to induce osteoclastogenesis. In this study, we demonstrated that SB239063, a p38-specific inhibitor, suppressed osteoclastogenesis and bone resorption via inhibiting phosphorylation of MEF2C (myocyte enhancer factor 2C) and subsequently leading to MEF2C degradation by ubiquitination. Knockdown of MEF2C impaired osteoclast formation due to decreased c-Fos expression. Furthermore, MEF2C can directly bind to the promoter region of c-Fos to initiate its transcription. Interestingly, overexpression of either MEF2C or c-Fos can partially rescue the inhibitory effect of SB239063 on osteoclastogenesis. In addition, in vivo data proved that SB239063 also played a preventive role in both LPS (lipopolysaccharide)- and OVX (ovariectomy)-induced bone loss in mice. In conclusion, our results show that SB239063 can be a potential therapy for osteolytic diseases, and a novel p38/MEF2C/c-Fos axis is essential for osteoclastogenesis.

USP22 Deubiquitinates CD274 to Suppress Anticancer Immunity

PD-1 (CD279)-PD-L1 (CD274) inhibitory signaling is critical for cancer immune evasion, and thus has become one of the major targets in anticancer immunotherapy. There are several studies that demonstrate the potent effects of posttranslational modifications of CD274 on immune inactivation and suppression, such as ubiquitination, phosphorylation, glycosylation, and palmitoylation. However, the regulatory mechanisms for CD274 deubiquitination are still largely unclear. Here, we identified ubiquitin-specific protease 22 (USP22) as a novel deubiquitinase of CD274. USP22 directly interacted with the C terminus of CD274, inducing its deubiquitination and stabilization. Across multiple cancer types, USP22 was highly expressed and frequently altered in liver cancer, closely correlating with poor prognosis of these patients. Genetic depletion of USP22 inhibited liver cancer growth in an immune system-dependent manner, increased tumor immunogenicity and tumor-infiltrating lymphocytes, and improved therapeutic efficacy of CD274-targeted immunotherapy and CDDP-based chemotherapy in mice. We demonstrate that targeting USP22 is a promising strategy to potentiate anticancer immunity for CD274-amplified cancer.

Melittin Inhibits Hypoxia-Induced Vasculogenic Mimicry Formation and Epithelial-Mesenchymal Transition through Suppression of HIF-1α/Akt Pathway in Liver Cancer

In this study, we investigated whether melittin could suppress hypoxia-induced vasculogenic mimicry (VM) formation in liver cancer and explored the underlying mechanisms. Melittin significantly inhibited the proliferation of liver cancer cells with or without CoCl₂ presence. Melittin also significantly inhibited CoCl₂-induced migration, invasion, and VM formation of liver cancer cells. CoCl₂ treatment suppressed the expression of E-cadherin and elevated the expression of N-cadherin and Vimentin. Melittin reversed the changes in the protein and mRNA levels of these epithelial-mesenchymal transition (EMT) markers. CoCl₂-induced accumulation of HIF-1α increased the level of phosphorylated Akt and upregulated the expression of VEGF and MMP-2/9. Melittin decreased the HIF-1α level and thereby suppressed the levels of p-Akt, VEGF, and MMP-2/9. In addition, the inhibitor of PI3K/Akt also suppressed CoCl₂-induced EMT and liver cancer cells migration, and the activator of Akt, SC-79, partly blocked the effect of melittin on CoCl₂-induced EMT and liver cancer cells migration. In the xenograft tumor model in nude mice, melittin treatment significantly suppressed the tumor growth, VM formation, and HIF-1α expression in the tumor. In conclusion, this study indicates melittin may inhibit hypoxia-induced VM formation and EMT in liver cancer through inhibiting HIF-1α/Akt pathway.

USP20 positively regulates tumorigenesis and chemoresistance through β-catenin stabilization

β-catenin is a major transcriptional activator of the canonical Wnt/β-catenin signaling pathway. It is important for a series of biological processes including tissue homeostasis, and embryonic development and is involved in various human diseases. Elevated oncogenic activity of β-catenin is frequently observed in cancers, which contributes to survival, metastasis and chemo-resistance of cancer cells. However, the mechanism of β-catenin overexpression in cancers is not well defined. Here we demonstrate that the deubiquitination enzyme USP20 is a new regulator of the Wnt/β-catenin signaling pathway. Mechanistically, USP20 regulates the deubiquitination of β-catenin to control its stability, thereby inducing proliferation, invasion and migration of cancer cells. High expression of USP20 correlates with increased β-catenin protein level in multiple cancer cell lines and patient samples. Moreover, knockdown of USP20 increases β-catenin polyubiquitination, which enhances β-catenin turnover and cell sensitivity to chemotherapy. Collectively, our results establish the USP20-β-catenin axis as a critical regulatory mechanism of canonical Wnt/β-catenin signaling pathway with an important role in tumorigenesis and chemo response in human cancers.

Up-regulation of miR-340-5p promotes progression of thyroid cancer by inhibiting BMP4

PURPOSE

The incidence of thyroid cancer is increasing and the proliferation of thyroid cancer cells is incompletely understood. microRNAs may play key roles in thyroid cancer progression.

METHODS

We analyzed miR-340-5p in thyroid cancer tissue and normal tissue, and using informatics to predict its target. Cell lines and a mouse model were used to study the role of miR-340-5p in cancer proliferation.

RESULTS

Overexpression of miR-340-5p was found in thyroid cancer specimens. Tumors with higher pathological grade had higher levels of miR-340-5p. Overexpression of miR-340-5p significantly enhanced cell viability and colony formation. Treatment of anti-miR-340-5p, however, showed opposite alterations. We predicted that bone morphogenetic protein 4 (BMP4) is a possible target, and found a negative correlation between miR-340-5p and BMP4 levels in thyroid cancer tissue. miR-340-5p reduced BMP4 expression. BMP4 overexpression attenuated the effects of miR-340-5p in cell viability and colony formation. In addition, using a xenograft mouse model we proved that anti-miR-340-5p was able to inhibit tumor growth.

CONCLUSIONS

miR-340-5p promotes thyroid cancer proliferation by inhibiting BMP4. Anti-miR-340-5p can be a promising strategy to control thyroid cancer.

MiR-494-3p promotes PI3K/AKT pathway hyperactivation and human hepatocellular carcinoma progression by targeting PTEN

Recent studies have shown that miR-494-3p is oncogene and has a central role in many solid tumors; however, the role of miR-494-3p in the progression and prognosis of hepatocellular carcinoma (HCC) remains unknown. In this study, it was found that miR-494-3p was up-regulated in HCC tissues. The high level of miR-494-3p in HCC tumors was correlated with aggressive clinicopathological characteristics and predicted poor prognosis in HCC patients. Functional study demonstrated that miR-494-3p significantly promoted HCC cell metastasis in vitro and vivo. Since phosphoinositide 3-kinase/protein kinase-B (PI3K/AKT) signaling is a basic oncogenic driver in HCC, a potential role of miR-494-3p was explored as well as its target genes in PI3K/AKT activation. Of all the predicted target genes of miR-494-3p, the tumor-suppressor phosphatase and tensin homolog (PTEN) were identified. In conclusion, the data we collected could define an original mechanism of PI3K/AKT hyperactivation and sketch the regulatory role of miR-494-3p in suppressing the expression of PTEN. Therefore, targeting miR-494-3p could provide an effective therapeutic method for the treatment of the disease.

MEF2 and the tumorigenic process, hic sunt leones

While MEF2 transcription factors are well known to cooperate in orchestrating cell fate and adaptive responses during development and adult life, additional studies over the last decade have identified a wide spectrum of genetic alterations of MEF2 in different cancers. The consequences of these alterations, including triggering and maintaining the tumorigenic process, are not entirely clear. A deeper knowledge of the molecular pathways that regulate MEF2 expression and function, as well as the nature and consequences of MEF2 mutations are necessary to fully understand the many roles of MEF2 in malignant cells. This review discusses the current knowledge of MEF2 transcription factors in cancer.

Heterozygous CDKL5 Knockout Female Mice Are a Valuable Animal Model for CDKL5 Disorder

CDKL5 disorder is a severe neurodevelopmental disorder caused by mutations in the X-linked CDKL5 (cyclin-dependent kinase-like five) gene. CDKL5 disorder primarily affects girls and is characterized by early-onset epileptic seizures, gross motor impairment, intellectual disability, and autistic features. Although all CDKL5 female patients are heterozygous, the most valid disease-related model, the heterozygous female Cdkl5 knockout (Cdkl5 +/−) mouse, has been little characterized. The lack of detailed behavioral profiling of this model remains a crucial gap that must be addressed in order to advance preclinical studies. Here, we provide a behavioral and molecular characterization of heterozygous Cdkl5 +/− mice. We found that Cdkl5 +/− mice reliably recapitulate several aspects of CDKL5 disorder, including autistic-like behaviors, defects in motor coordination and memory performance, and breathing abnormalities. These defects are associated with neuroanatomical alterations, such as reduced dendritic arborization and spine density of hippocampal neurons. Interestingly, Cdkl5 +/− mice show age-related alterations in protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) signaling, two crucial signaling pathways involved in many neurodevelopmental processes. In conclusion, our study provides a comprehensive overview of neurobehavioral phenotypes of heterozygous female Cdkl5 +/− mice and demonstrates that the heterozygous female might be a valuable animal model in preclinical studies on CDKL5 disorder.

The multifaceted role of exosomes in cancer progression: diagnostic and therapeutic implications [corrected]

BACKGROUND

Recent advances in cancer biology have highlighted the relevance of exosomes and nanovesicles as carriers of genetic and biological messages between cancer cells and their immediate and/or distant environments. It has been found that these molecular cues may play significant roles in cancer progression and metastasis. Cancer cells secrete exosomes containing diverse molecules that can be transferred to recipient cells and/or vice versa to induce a plethora of biological processes, including angiogenesis, metastasis formation, therapeutic resistance, epithelial-mesenchymal transition and epigenetic/stemness (re)programming. While exosomes interact with cells within the tumour microenvironment to promote tumour growth, these vesicles can also facilitate the process of distant metastasis by mediating the formation of pre-metastatic niches. Next to their tumour promoting effects, exosomes have been found to serve as potential tools for cancer diagnosis and therapy. The ease of isolating exosomes and their content from different body fluids has led to the identification of diagnostic and prognostic biomarker signatures, as well as to predictive biomarker signatures for therapeutic responses. Exosomes can also be used as cargos to deliver therapeutic anti-cancer drugs, and they can be engineered to serve as vaccines for immunotherapy. Additionally, it has been found that inhibition of exosome secretion, and thus the transfer of oncogenic molecules, holds promise for inhibiting tumour growth. Here we provide recent information on the diverse roles of exosomes in various cellular and systemic processes governing cancer progression, and discuss novel strategies to halt this progression using exosome-based targeted therapies and methods to inhibit exosome secretion and the transfer of pro-tumorigenic molecules.

CONCLUSIONS

This review highlights the important role of exosomes in cancer progression and its implications for (non-invasive) diagnostics and the development of novel therapeutic strategies, as well as its current and future applications in clinical trials.

PVT1 regulates the malignant behaviors of human glioma cells by targeting miR-190a-5p and miR-488-3p

The long non-coding RNA (lncRNA) PVT1 is reported to be involved in tumorigenesis and the progression of many malignancies. However, the function of PVT1 in gliomas remains unclarified. The present study demonstrated the expression level of PVT1 using qRT-PCR. The role of PVT1 in the regulation of biological behaviors of glioma cells was investigated using CCK-8 assay, Transwell assay and flow cytometry. The possible molecular mechanisms were also elucidated. In our results, PVT1 was up-regulated in glioma specimens and cell lines. Knockdown of PVT1 impaired the malignant behaviors of glioma cells via the suppression of proliferation, migration and invasion, as well as through promotion of apoptosis. Furthermore, PVT1 was identified to affect the glioma cells via binding to miR-190a-5p and miR-488-3p, which were down-regulated and played tumor suppressor roles in glioma cells. Up-regulated miR-190a-5p or miR-488-3p partially rescued the suppressive effect induced by PVT1 knockdown. Myocyte enhancer factor 2C (MEF2C) was a direct downstream target of miR-190a-5p and miR-488-3p, which was proved to be an oncogene and involved in the PVT1 knockdown induced regulation of biological behaviors of glioma cells. Over-expression of MEF2C up-regulated JAGGED1 by increasing the promoter activity of JAGGED1. PVT1 knockdown combined with miR-190a-5p and miR-488-3p over-expression contributed to the smallest tumor volume and the longest survivals in nude mice. In conclusion, PVT1-miR-190a-5p/miR-488-3p-MEF2C-JAGGED1 axis is involved in proliferation and progression of glioma. Thus, PVT1 may become a novel target in glioma therapy.

Overexpression of leucine-rich repeat-containing G protein-coupled receptor 5 predicts poor prognosis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies and the fifth leading cause of cancer-related death worldwide. Novel prognostic biomarkers are urgently needed for patients with HCC. Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) overexpression may promote tumor metastasis in HCC. However, few studies investigate the prognosis predictive role of LGR5 in patients with HCC. Herein, we aimed to examine the expression level of LGR5 in tumors and its correlation with clinical characteristics and survivals of patients with HCC. LGR5 expression in tumor specimens and adjacent tissue resected from 66 patients were detected by immunohistochemistry. The results showed that the expression of LGR5 was markedly higher in HCC than in normal adjacent tissues (P = .006). High expression of LGR5 was significantly correlated with later disease stage (P = .009). In addition, high LGR5 expression was remarkably correlated with short overall survival than those with low LGR5 expression (P < .05). The median overall survival of patients with high LGR5 expression was 12 months, whereas that of patients with low LGR5 expression was still not reached (longer than 70 months). Notably, in our limited cases, we did not detect any difference in tumor size, lymphatic invasion, or metastasis in patients with high or low expression of LGR5. In conclusion, high protein level of LGR5 was associated with poor prognosis of these patients. LGR5 appears to be a valuable prognostic predictor clinically and a potential target in HCC therapy.

Long non-coding RNA deep sequencing reveals the role of macrophage in liver disorders

Liver disorders such as hepatitis, cirrhosis and hepatocellular carcinoma are a series of the most life threatening diseases along with extensive inflammatory cellular infiltrations. Macrophage has been proved to be key regulators and initiators of inflammation, and long non-coding RNAs (lncRNAs) are recommended to play critical roles in the occurrence and development of a variety of diseases. To uncover the role of macrophage in liver disorders via lncRNA sequencing method, we first applied a lncRNA classification pipeline to identify 1247 lncRNAs represented on the Affymetrix Mouse Genome 430/430A 2.0 array. We then analyzed the lncRNA expression patterns in a set of previously published gene expression profiles of silica particle exposed macrophages and liver respectively, and identified and validated sets of differentially expressed lncRNAs shared by macrophages and liver. The functional enrichment analysis of these lncRNAs was processed on the basis of their expression signatures, three aspects including cis, trans and co-acting proteins were proposed. This is the first time to correlate macrophage with liver disorders via co-expressed lncRNAs. Our findings indicated that roles of macrophage in liver disorders were double-edged, the differentially expressed lncRNAs and their corresponding regulatory genes or proteins may serve as potential diagnostic biomarkers and therapeutic targets.

Inhibition of MK2 suppresses IL-1β, IL-6, and TNF-α-dependent colorectal cancer growth

Colorectal cancer (CRC) development and progression is associated with chronic inflammation. We have identified the MAPK-activated protein kinase 2 (MK2) pathway as a primary mediator of inflammation in CRC. MK2 signaling promotes production of proinflammatory cytokines IL-1β, IL-6 and TNF-α. These cytokines have been implicated in tumor growth, invasion and metastasis. For the first time, we investigate whether MK2 inhibition can improve outcome in two mouse models of CRC. In our azoxymethane/dextran sodium sulfate (AOM/DSS) model of colitis-associated CRC, MK2 inhibitor treatment eliminated murine tumor development. Using the implanted, syngeneic murine CRC cell line CT26, we observe significant tumor volume reduction following MK2 inhibition. Tumor cells treated with MK2 inhibitors produced 80% less IL-1β, IL-6 and TNF-α and demonstrated decreased invasion. Replenishment of downstream proinflammatory MK2-mediated cytokines (IL-1β, IL-6 and TNF-α) to tumors led to restoration of tumor proliferation and rapid tumor regrowth. These results demonstrate the importance of MK2 in driving proinflammatory cytokine production, its relevance to in vivo tumor proliferation and invasion. Inhibition of MK2 may represent an attractive therapeutic target to suppress tumor growth and progression in patients.

MEF2 signaling and human diseases

The members of myocyte Enhancer Factor 2 (MEF2) protein family was previously believed to function in the development of heart and muscle. Recent reports indicate that they are also closely associated with development and progression of many human diseases. Although their role in cancer biology is well established, the molecular mechanisms underlying their action is yet largely unknown. MEF2 family is closely associated with various signaling pathways, including Ca²⁺ signaling, MAP kinase signaling, Wnt signaling, PI3K/Akt signaling, etc. microRNAs also contribute to regulate the activities of MEF2. In this review, we summarize the known molecular mechanism by which MEF2 family contribute to human diseases.

Integrative Analysis of Transcription Factor Combinatorial Interactions Using a Bayesian Tensor Factorization Approach

Transcription factors play a key role in transcriptional regulation of genes and determination of cellular identity through combinatorial interactions. However, current studies about combinatorial regulation is deficient due to lack of experimental data in the same cellular environment and extensive existence of data noise. Here, we adopt a Bayesian CANDECOMP/PARAFAC (CP) factorization approach (BCPF) to integrate multiple datasets in a network paradigm for determining precise TF interaction landscapes. In our first application, we apply BCPF to integrate three networks built based on diverse datasets of multiple cell lines from ENCODE respectively to predict a global and precise TF interaction network. This network gives 38 novel TF interactions with distinct biological functions. In our second application, we apply BCPF to seven types of cell type TF regulatory networks and predict seven cell lineage TF interaction networks, respectively. By further exploring the dynamics and modularity of them, we find cell lineage-specific hub TFs participate in cell type or lineage-specific regulation by interacting with non-specific TFs. Furthermore, we illustrate the biological function of hub TFs by taking those of cancer lineage and blood lineage as examples. Taken together, our integrative analysis can reveal more precise and extensive description about human TF combinatorial interactions.

Overexpression of hepatocyte nuclear factor 4α in human mesenchymal stem cells suppresses hepatocellular carcinoma development through Wnt/β-catenin signaling pathway downregulation

Mesenchymal stem cells (MSCs) hold promise as cellular vehicles for the delivery of therapeutic gene products because they can be isolated, expanded, and genetically modified in vitro and possess tumor-oriented homing capacity in vivo. (1) Hepatocyte nuclear factor 4α (HNF4α) is a dominant transcriptional regulator of hepatocyte differentiation and hepatocellular carcinogenesis (HCC). (2,3) We have previously demonstrated that overexpression of HNF4α activates various hepatic-specific genes and enhances MSC differentiation. (4) However, the extent that overexpression of HNF4α in MSCs influences HCC progression has yet to be examined. Here we sought to investigate what effect MSCs overexpressing HNF4α (MSC-HNF4α) have on human hepatoma cells in vitro and in vivo. Conditioned medium collected from in vitro MSC-HNF4α cultures significantly inhibited hepatoma cell growth and metastasis compared with controls. Additionally, nude mice administered MSC-HNF4α exhibited significantly smaller tumors compared with controls in vivo. Immunoblot analysis of HCC cells treated with MSC-HNF4α displayed downregulated β-catenin, cyclinD1, c-Myc, MMP2 and MMP9. Taken together, our results demonstrate that MSC-HNF4α inhibits HCC progression by reducing hepatoma cell growth and metastasis through downregulation of the Wnt/β-catenin signaling pathway.

Identification of novel genetic regulations associated with airway epithelial homeostasis using next-generation sequencing data and bioinformatics approaches

Airway epithelial cells play important roles in airway remodeling. Understanding gene regulations in airway epithelial homeostasis may provide new insights into pathogenesis and treatment of asthma. This study aimed to combine gene expression (GE) microarray, next generation sequencing (NGS), and bioinformatics to explore genetic regulations associated with airway epithelial homeostasis. We analyzed expression profiles of mRNAs (GE microarray) and microRNAs (NGS) in normal and asthmatic bronchial epithelial cells, and identified 9 genes with potential microRNA-mRNA interactions. Of these 9 dysregulated genes, downregulation of MEF2C and MDGA1 were validated in a representative microarray (GSE43696) from the gene expression omnibus (GEO) database. Our findings suggested that upregulated mir-203a may repress MEF2C, a transcription factor, leading to decreased cellular proliferation. In addition, upregulated mir-3065-3p may repress MDGA1, a cell membrane anchor protein, resulting in suppression of cell-cell adhesion. We also found that KCNJ2, a potassium channel, was downregulated in severe asthma and may promote epithelial cell apoptosis. We proposed that aberrant regulations of mir-203a-MEF2C and mir-3065-3p-MDGA1, as well as downregulation of KCNJ2, play important roles in airway epithelial homeostasis in asthma. These findings provide new perspectives on diagnostic or therapeutic strategies targeting bronchial epithelium for asthma. The approach in this study also provides a new aspect of studying asthma.

Biomarkers in hepatocellular carcinoma: an overview

Current methods for HCC diagnosis have not an optimal diagnostic accuracy. The detection of more than one biomarker seems to improve their individual performance and provide an accurate HCC diagnosis approach. Individual gene expression seems to influence whether or not the treatment is successful, since several molecules have interfere with cancer associated pathways and have been related to poor prognosis which condition the lack of effective treatment options. Areas covered: Novel biomarkers have been proposed as a useful tool in each patient prognosis. This article aims to review the recent evidence based on HCC biomarkers which seems to have a regulative role according to tumor cell development leading to a specific biological response. Epigenetic regulation, miRNAs, and genome sequencing analysis propose molecular expression signatures as novel biomarkers which allowed achieve the major goal for the use of biomarkers in clinical practice. Moreover, a deeper analysis for determine the diagnostic accuracy of biomarkers has been made. Expert commentary: To improve of methodological designs and sample sizes are needed in order to support the role of biomarkers in HCC. Furthermore, is necessary to consider HCC etiologies and all clinic disease context to carried out clinical phase studies to thrust biomarkers application.

The co-existence of transcriptional activator and transcriptional repressor MEF2 complexes influences tumor aggressiveness

The contribution of MEF2 TFs to the tumorigenic process is still mysterious. Here we clarify that MEF2 can support both pro-oncogenic or tumor suppressive activities depending on the interaction with co-activators or co-repressors partners. Through these interactions MEF2 supervise histone modifications associated with gene activation/repression, such as H3K4 methylation and H3K27 acetylation. Critical switches for the generation of a MEF2 repressive environment are class IIa HDACs. In leiomyosarcomas (LMS), this two-faced trait of MEF2 is relevant for tumor aggressiveness. Class IIa HDACs are overexpressed in 22% of LMS, where high levels of MEF2, HDAC4 and HDAC9 inversely correlate with overall survival. The knock out of HDAC9 suppresses the transformed phenotype of LMS cells, by restoring the transcriptional proficiency of some MEF2-target loci. HDAC9 coordinates also the demethylation of H3K4me3 at the promoters of MEF2-target genes. Moreover, we show that class IIa HDACs do not bind all the regulative elements bound by MEF2. Hence, in a cell MEF2-target genes actively transcribed and strongly repressed can coexist. However, these repressed MEF2-targets are poised in terms of chromatin signature. Overall our results candidate class IIa HDACs and HDAC9 in particular, as druggable targets for a therapeutic intervention in LMS.

The tumorigenic process is characterized by profound alterations of the transcriptional landscape, aimed to sustain uncontrolled cell growth, resistance to apoptosis and metastasis. The contribution of MEF2, a pleiotropic family of transcription factors, to these changes is controversial, since both pro-oncogenic and tumor-suppressive activities have been reported. To clarify this paradox, we studied the role of MEF2 in an aggressive type of soft-tissue sarcomas, the leiomyosarcomas (LMS). We found that in LMS cells MEF2 become oncogenes when in complex with class IIa HDACs. We have identified different sub-classes of MEF2-target genes and observed that HDAC9 converts MEF2 into transcriptional repressors on some, but not all, MEF2-regulated loci. This conversion correlates with the acquisition by MEF2 of oncogenic properties. We have also elucidated some epigenetic re-arrangements supervised by MEF2. In summary, our studies suggest that the paradoxical actions of MEF2 in cancer can be explained by their dual role as activators/repressors of transcription and open new possibilities for therapeutic interventions.