Loss of miR-107, miR-181c and miR-29a-3p Promote Activation of Notch2 Signaling in Pediatric High-Grade Gliomas (pHGGs)

Intracerebellar administration of the chemokine Cxcl3 reduces the volume of medulloblastoma lesions at an advanced stage by promoting the migration and differentiation of preneoplastic precursor cells

The prognosis for many pediatric brain tumors, including cerebellar medulloblastoma (MB), remains dismal but there is promise in new therapies. We have previously generated a mouse model developing spontaneous MB at high frequency, Ptch1+/-/Tis21-/-. In this model, reproducing human tumorigenesis, we identified the decline of the Cxcl3 chemokine in cerebellar granule cell precursors (GCPs) as responsible for a migration defect, which causes GCPs to stay longer in the proliferative area rather than differentiate and migrate internally, making them targets of transforming insults. We demonstrated that 4-week Cxcl3 infusion in cerebella of 1-month-old mice, at the initial stage of MB formation, forces preneoplastic GCPs (pGCPs) to leave lesions and differentiate, with a complete suppression of MB development. In this study, we sought to verify the effect of 4-week Cxcl3 treatment in 3-month-old Ptch1+/-/Tis21-/- mice, when MB lesions are at an advanced, irreversible stage. We found that Cxcl3 treatment reduces tumor volumes by sevenfold and stimulates the migration and differentiation of pGCPs from the lesion to the internal cerebellar layers. We also tested whether the pro-migratory action of Cxcl3 favors metastases formation, by xenografting DAOY human MB cells in the cerebellum of immunosuppressed mice. We showed that DAOY cells express the Cxcl3 receptor, Cxcr2, and that Cxcl3 triggers their migration. However, Cxcl3 did not significantly affect the frequency of metastases or the growth of DAOY-generated MBs. Finally, we mapped the expression of the Cxcr2 receptor in human MBs, by evaluating a well-characterized series of 52 human MBs belonging to different MB molecular subgroups. We found that Cxcr2 was variably expressed in all MB subgroups, suggesting that Cxcl3 could be used for therapy of different MBs.

Circulating miR-26b-5p and miR-451a as diagnostic biomarkers in medullary thyroid carcinoma patients

PURPOSE/METHODS

The determination of tumour biomarkers is paramount to advancing personalized medicine, more so in rare tumours like medullary thyroid carcinoma (MTC), whose diagnosis is still challenging. The aim of this study was to identify non-invasive circulating biomarkers in MTC. To achieve this goal, paired MTC tissue and plasma extracellular vesicle samples were collected from multiple centres and microRNA (miRNA) expression levels were evaluated.

RESULTS

The samples from a discovery cohort of 23 MTC patients were analysed using miRNA arrays. Lasso logistic regression analysis resulted in the identification of a set of circulating miRNAs as diagnostic biomarkers. Among them, miR-26b-5p and miR-451a, were highly expressed and their expression decreased during follow-up in disease-free patients in the discovery cohort. Circulating miR-26b-5p and miR-451a were validated using droplet digital PCR in a second independent cohort of 12 MTC patients.

CONCLUSION

This study allowed the identification and validation of a signature of two circulating miRNAs, miR-26b-5p and miR-451a, in two independent cohorts reporting a significant diagnostic performance for MTC. The results of this study offer advancements in molecular diagnosis of MTC proposing a novel non-invasive tool to use in precision medicine.

Nanoparticles for Drug and Gene Delivery in Pediatric Brain Tumors' Cancer Stem Cells: Current Knowledge and Future Perspectives

Primary malignant brain tumors are the most common solid neoplasm in childhood. Despite recent advances, many children affected by aggressive or metastatic brain tumors still present poor prognosis, therefore the development of more effective therapies is urgent. Cancer stem cells (CSCs) have been discovered and isolated in both pediatric and adult patients with brain tumors (e.g., medulloblastoma, gliomas and ependymoma). CSCs are a small clonal population of cancer cells responsible for brain tumor initiation, maintenance and progression, displaying resistance to conventional anticancer therapies. CSCs are characterized by a specific repertoire of surface markers and intracellular specific pathways. These unique features of CSCs biology offer the opportunity to build therapeutic approaches to specifically target these cells in the complex tumor bulk. Treatment of pediatric brain tumors with classical chemotherapeutic regimen poses challenges both for tumor location and for the presence of the blood-brain barrier (BBB). Lastly, the application of chemotherapy to a developing brain is followed by long-term sequelae, especially on cognitive abilities. Novel avenues are emerging in the therapeutic panorama taking advantage of nanomedicine. In this review we will summarize nanoparticle-based approaches and the efficacy that NPs have intrinsically demonstrated and how they are also decorated by biomolecules. Furthermore, we propose novel cargoes together with recent advances in nanoparticle design/synthesis with the final aim to specifically target the insidious CSCs population in the tumor bulk.

A Dynamic Role of Mastermind-Like 1: A Journey Through the Main (Path)ways Between Development and Cancer

Major signaling pathways, such as Notch, Hedgehog (Hh), Wnt/β-catenin and Hippo, are targeted by a plethora of physiological and pathological stimuli, ultimately resulting in the modulation of genes that act coordinately to establish specific biological processes. Many biological programs are strictly controlled by the assembly of multiprotein complexes into the nucleus, where a regulated recruitment of specific transcription factors and coactivators on gene promoter region leads to different transcriptional outcomes. MAML1 results to be a versatile coactivator, able to set up synergistic interlinking with pivotal signaling cascades and able to coordinate the network of cross-talking pathways. Accordingly, despite its original identification as a component of the Notch signaling pathway, several recent reports suggest a more articulated role for MAML1 protein, showing that it is able to sustain/empower Wnt/β-catenin, Hh and Hippo pathways, in a Notch-independent manner. For this reason, MAML1 may be associated to a molecular “switch”, with the function to control the activation of major signaling pathways, triggering in this way critical biological processes during embryonic and post-natal life. In this review, we summarize the current knowledge about the pleiotropic role played by MAML proteins, in particular MAML1, and we recapitulate how it takes part actively in physiological and pathological signaling networks. On this point, we also discuss the contribution of MAML proteins to malignant transformation. Accordingly, genetic alterations or impaired expression of MAML proteins may lead to a deregulated crosstalk among the pathways, culminating in a series of pathological disorders, including cancer development. Given their central role, a better knowledge of the molecular mechanisms that regulate the interplay of MAML proteins with several signaling pathways involved in tumorigenesis may open up novel opportunities for an attractive molecular targeted anticancer therapy.

Role of tissue and circulating microRNAs and DNA as biomarkers in medullary thyroid cancer

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor comprising hereditary or sporadic form with frequent mutations in the rearranged during transfection (RET) or RAS genes. Diagnosis is based on the presence of thyroid tumor mass with altered levels of calcitonin (Ctn) and carcinoembryonal antigen (CEA) in the serum and/or in the cytological smears from fine needle aspiration biopsies. Treatment consists of total thyroidectomy, followed by tyrosine kinase inhibitors (TKi) in case of disease persistence. During TKi treatment, Ctn and CEA levels can fluctuate regardless of tumor volume, metastasis or response to therapy. Research for more reliable non-invasive biomarkers in MTC is still underway. In this context, circulating nucleic acids, namely circulating microRNAs (miRNAs) and cell free DNA (cfDNA), have been evaluated by different research groups. Aiming to shed light on whether miRNAs and cfDNA are suitable as MTC biomarkers we searched three different databases, PubMed, Scopus, WOS and reviewed the literature. We classified 83 publications fulfilling our search criteria and summarized the results. We report data on miRNAs and cfDNA that can be evaluated for validation in independent studies and clinical application.

circKRT7-miR-29a-3p-COL1A1 Axis Promotes Ovarian Cancer Cell Progression

Background

Circular RNA (circRNA) has emerged as an important regulator in the progression of human diseases. However, the role of circRNAs in ovarian cancer remains largely unknown.

Materials and Methods

DNA sequencing and PCR were used to identify the existence and expression of circKRT7. The targeting relationship between circKRT7/miR-29a-3p and miR-29a-3p/COL1A1 was verified by fluorescence reporter assay. In vitro, colony formation, transwell and wound healing assay were used to detect the effects of circKRT7 and miR-29a-3p on the proliferation, migration and invasion ability of ovarian cancer cells. In vivo, xenograft tumor model was performed to validate the role of circKRT7 and miR-29a-3p in tumor growth.

Results

We found that circKRT7 can promote the proliferation and metastasis of ovarian cancer cells by absorbing miR-29a-3p, which leads to the up-regulation of COL1A1. In vitro, knock-down of circKRT7 can inhibit the migration and invasion of ovarian cancer cells. This effect of circKRT7 is achieved by adsorbing miR-29a-3p and subsequently COL1A1 release. In vivo experiments, the reduction of circKRT7 expression can also slow tumor growth, and this inhibition was partly counteracted after miR-29a-3p repression.

Conclusion

Overall, circKRT7 promotes EMT-related cell progression by absorbing miR-29a-3p in ovarian cancer. This suggests the crucial role of circular RNA in the malignant evolution in cancer.

microRNA-181 serves as a dual-role regulator in the development of human cancers

MicroRNAs (miRNAs) as the regulatory short noncoding RNAs are involved in a wide array of cellular and molecular processes. They negatively regulate gene expression and their dysfunction is correlated with cancer development through modulation of multiple signaling pathways. Therefore, these molecules could be considered as novel biomarkers and therapeutic targets for more effective management of human cancers. Recent studies have demonstrated that the miR-181 family is dysregulated in various tumor tissues and plays a pivotal role in carcinogenesis. They have been shown to act as oncomirs or tumor suppressors considering their mRNA targets and to be involved in cell proliferation, apoptosis, autophagy, angiogenesis and drug resistance. Additionally, these miRNAs have been demonstrated to exert their regulatory effects through modulating multiple signaling pathways including PI3K/AKT, MAPK, TGF-b, Wnt, NF-κB, Notch pathways. Given that, in this review, we briefly summarise the recent studies that have focused on the roles of miRNA-181 family as the multifunctional miRNAs in tumorigenesis and cancer development. These miRNAs may serve as diagnostic and prognostic biomarkers or therapeutic targets in human cancer gene therapy.

Wnt, Notch, and TGF-β Pathways Impinge on Hedgehog Signaling Complexity: An Open Window on Cancer

Constitutive activation of the Hedgehog (Hh) signaling pathway is associated with increased risk of developing several malignancies. The biological and pathogenic importance of Hh signaling emphasizes the need to control its action tightly, both physiologically and therapeutically. Evidence of crosstalk between Hh and other signaling pathways is reported in many tumor types. Here, we provide an overview of the current knowledge about the communication between Hh and major signaling pathways, such as Notch, Wnt, and transforming growth factor β (TGF-β), which play critical roles in both embryonic and adult life. When these pathways are unbalanced, impaired crosstalk contributes to disease development. It is reported that more than one of these pathways are active in different type of tumors, at the same time. Therefore, starting from a plethora of stimuli that activate multiple signaling pathways, we describe the signals that preferentially converge on the Hh signaling cascade that influence its activity. Moreover, we highlight several connection points between Hh and Notch, Wnt, or TGF-β pathways, showing a reciprocal synergism that contributes to tumorigenesis, supporting a more malignant behavior by tumor cells, such as in leukemia and brain tumors. Understanding the importance of these molecular interlinking networks will provide a rational basis for combined anticancer drug development.

MiR-181c affects estrogen-dependent endometrial carcinoma cell growth by targeting PTEN

MicroRNAs (miRNAs), which is a type of non-coding and single-stranded small molecule RNA, bind either completely or incompletely to 3'-UTR of the target gene mRNA to inhibit mRNA translation or degradation. In our study, we aimed to explore the roles and mechanisms of miR-181c in the apoptosis of RL95-2 human endometrial carcinoma cells. Cell activity and apoptosis were detected by cell counting Kit-8 (CCK-8) assay and flow cytometry (FCM), respectively. Related mRNAs and proteins expression was determined by quantitative real-time reverse transcription PCR (qRT-PCR) and western blot assays, respectively. The binding capacity of PTEN-3'-UTR and miR-181c was assessed by luciferase reporter assay. The obtained results suggested that E2 evidently increased the cell activity of RL95-2 cells. In addition, miR-181c inhibitor suppressed the cell viability and enhanced the apoptosis capacity of E2-induced RL95-2 cells and distinctly reduced the miR-181c expression. We also found that miR-181c could bind to PTEN-3'-UTR and miR-181c inhibitor up-regulated the expression level of PTEN in E2-induced RL95-2 cells. Besides, overexpression of PTEN markedly promoted the apoptosis of E2-induced RL95-2 cells through regulating the Bax and Bcl-2 expression, and modulated the expression of AKT pathway, p53 and Cyclin D. In conclusion, our findings revealed that miR-181c affected the estrogen-dependent endometrial carcinoma cell growth by targeting PTEN. The potential effects of miR-181c on the apoptosis of E2-induced RL95-2 cells suggest that miR-181c could be an effective target for endometrial carcinoma therapies.

microRNA-29a inhibits cardiac fibrosis in Sprague-Dawley rats by downregulating the expression of DNMT3A

Objective:

This study aims to investigate the effect of miR-29a targeting the regulation of DNMT3A on the development of cardiac fibrosis in Sprague-Dawley (SD) rats.

Methods:

In vivo experiment: SD rats were randomly divided into model and control groups. The cardiac and left ventricular indices in each group were calculated. The pathological changes of the myocardium were observed. The expression levels of miR-29a, CollA1, α-SMA, and DNMT3A in the myocardium of each group were detected. In vitro experiment: The cardiac fibroblasts (CFs) of SD rats were isolated from the myocardial tissue of SD rats and cultured. The miR-29a mimics, inhibitors, DNMT3A-siRNA, and control-siRNA were transfected into CFs. The expression levels of miR-29a, DNMT3A, CollA1, and α-SMA were detected, and the proliferation of CFs after transfection was observed.

Results:

The heart weight index of the rats in the model group increased significantly compared with that in the control group. Obvious collagen deposition was observed in the myocardial tissue of the model group. The expression levels of CollA1, α-SMA, and DNMT3A in the model group were significantly higher than those in the control group (p<0.05).

Conclusion:

miR-29a reduced the activation and proliferation of CFs to improve cardiac fibrosis probably by the downregulation of DNMT3A.

The role of oncogenic Notch2 signaling in cancer: a novel therapeutic target

Deregulated Notch signaling is a key factor thought to facilitate the stem-like proliferation of cancer cells, thereby facilitating disease progression. Four subtypes of Notch receptor have been described to date, with each playing a distinct role in cancer development and progression, therefore warranting a careful and comprehensive examination of the targeting of each receptor subtype in the context of oncogenesis. Clinical efforts to translate the DAPT, which blocks Notch signaling, have been unsuccessful due to a combination of serious gastrointestinal side effects and a lack of complete blocking efficacy. There is therefore a clear need to identify better therapeutic strategies for targeting and manipulating Notch signaling. Notch2 is a Notch receptor that is commonly overexpressed in a range of cancers, and which is linked to a unique oncogenic mechanism. Successful efforts to block Notch2 signaling will depend upon doing so both efficiently and specifically in patients. As such, in the present review we will explore the role of Notch2 signaling in the development and progression of cancer, and we will assess agents and strategies with the potential to effectively disrupt Notch2 signaling and thereby yield novel cancer treatment regimens.

MicroRNA‑181c suppresses growth and metastasis of hepatocellular carcinoma by modulating NCAPG

Purpose: Numerous studies have shown that the expression of microRNA-181c (miR-181c) is inhibited in various cancers, which suggests that it has a cancer suppressive effect. In the current study, we evaluated the regulation and characteristics of miR-181c in human hepatocellular carcinoma (HCC).

Materials and methods: Samples of tumor tissues and adjacent non-tumor tissues were collected from 52 patients with HCC, and expression levels of miR-181c in these samples were investigated via quantitative real-time polymerase chain reaction. HCC cell migration and invasion were investigated via wound healing assays and transwell assays. HCC cell apoptosis rates were assessed via flow cytometry, and HCC proliferation was assessed via 5-ethynyl-20-deoxyuridine assays. In vivo tumors were initiated by subcutaneously inoculating HCC cells into nude mice. And various biomarkers were investigated via western blotting.

Results: In microarray datasets and tumor tissues, significant downregulation of miR-181c was apparent compared with non-tumorous adjacent tissues. Expression of miR-181c in HCC cells was also significantly lower than it was in normal human liver cells. miR-181c regulated the migration, invasion, apoptosis, and proliferation of HCC cell lines in vitro, and tumor development in vivo. Observations also suggest that miR-181c regulates NCAPG in HCC cells, and its expression affects cellular invasion, migration, proliferation, and apoptosis. There was a negative correlation between miR-181c expression and NCAPG in HCC tissue samples.

Conclusion: miR-181c exhibits tumor-suppression via the regulation of NCAPG levels.

[MicroRNA-29a-3p regulates osteoblast differentiation and peri-implant osseointegration in a rat model of hyperlipidemia by modulating Frizzled 4 expression]

OBJECTIVE

This work aimed to study and identify the influence and target gene of microRNA-29a-3p (miR-29a-3p) in the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in a high-fat environment in vitro and in vivo.

METHODS

1) In vitro: BMSCs were randomly allocated into two groups and were then induced to undergo osteogenic differentiation in a normal or high-fat environment. Next, a miR-29a-3p mimic/inhibitor was transfected into the two groups of cells. The mRNA expression levels of alkaline phosphatase (ALP), Runt related gene 2 (Runx2), and miR-29a-3p and the protein expression levels of ALP and Runx2 were detected before and after transfection through reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot analyses. Moreover, Frizzled (Fzd) 4 was predicted as the target gene of miR-29a-3p by using an online database (Target Scan, MiRNA.org). The interactive relationship between miR-29a-3p and Fzd4 was confirmed through dual-luciferase assays. 2) In vivo: Rats were randomly divided into two groups and fed with a standard or high-fat diet. Titanium implants were grown in rats. Then, the expression levels of miR-29a-3p, ALP, and Runx2 were detected in bone tissues surrounding implants. Moreover, hard tissue sections were subjected to methylene blue-acid magenta staining and observed under microscopy to study bone formation around implants. In addition, miR-29a-3p-overexpressing lentiviral vectors were transfected into rats, and the expression levels of ALP, Runx2, and miR-29a-3p in bone tissues surrounding implants were detected at 3 and 10 days after transfection.

RESULTS

The expression levels of ALP, Runx2, and miR-29a-3p and the osteogenic differentiation of BMSCs were suppressed in high-fat groups in vitro and in vivo.

CONCLUSIONS

MiR-29a-3p plays a positive role in the regulation of BMSCs in a high-fat environment. It can increase ALP and Runx2 expression levels in bone tissues surrounding implants in hyperlipidemia models. This result implies that miR-29a-3p can promote implant osseointergration in a rat model of hyperlipidemia.

XPD suppresses cell proliferation and migration via miR-29a-3p-Mdm2/PDGF-B axis in HCC

Objective

The aim of this study was to investigate the role of XPD in migration and invasion of hepatocellular carcinoma (HCC) cells.

Methods

The expression of XPD and miR-29a-3p was examined by western blot and qRT-PCR, cell proliferation was detected by MTT assay, cell migration was detected by transwell assay. TargetScan was used to predict potential targets of miR-29a-3p.

Results

In this study, we found that the expression of XPD and miR-29a-3p was downregulated in HCC samples and HCC cell lines. XPD suppressed proliferation and migration of HCC cell via regulating miR-29a-3p expression. Target prediction analysis and dual-luciferase reporter assay confirmed Mdm2 and PDGF-B were direct targets of miR-29a-3p, and miR-29a-3p suppressed proliferation and migration of HCC cells via regulating the expression of Mdm2 or PDGF-B.

Conclusions

Our data indicated that XPD suppressed cell proliferation and migration via miR-29a-3p-Mdm2/PDGF-B axis in HCC.

miR-29a-3p inhibits growth, proliferation, and invasion of papillary thyroid carcinoma by suppressing NF-κB signaling via direct targeting of OTUB2

Background

Aberrant expression of microRNAs (miRNAs) is closely involved in cancer development. Downregulation of miR-29a-3p and its tumor suppressive roles in cancer have been revealed by multiple reporters. However, study of its expression pattern and function in papillary thyroid carcinoma (PTC) is rare.

Materials and methods

The expression of miR-29a-3p in PTC tissues and cells was detected by qPCR. CCK-8, plate clone formation, transwell invasion, Western blot, immunohistochem-istry, and luciferase reporter assays were carried out to identify the target of miR-29a-3p and explore its roles and mechanisms in PTC.

Results

Deregulated miR-29a-3p in PTC tissues and cell lines were revealed by qPCR. Restoring miR-29a-3p expression significantly inhibited growth, proliferation, and invasion of PTC cells demonstrated by CCK-8, plate clone formation, and transwell assays. Luciferase reporter assays showed miR-29a-3p can directly target OTUB2 in PTC cells. Ectopic expression of OTUB2 can antagonize the effects of miR-29a-3p on cell growth, proliferation, and invasion of PTC. Mechanistically, OTUB2 overexpression can activate NF-κB signaling mostly by stabilizing TRAF6. Upregulated OTUB2 expression was observed in PTC tissues via immunohistochemistry analysis. Moreover, OTUB2 showed a positive correlation to metastatic status and showed a negative correlation to the overall survival rate in PTC patients.

Conclusion

Deregulated miR-29a-3p can promote cell growth, proliferation, and invasion in PTC. OTUB2 is a direct downstream target of miR-29a-3p in PTC, and it mediates the effects of deregulated miR-29a-3p by activating TRAF6-associated NF-κB signaling in PTC.

Micro RNA as a potential blood-based epigenetic biomarker for Alzheimer's disease

As the prevalence of Alzheimer's disease (AD) increases, the search for a definitive, easy to access diagnostic biomarker has become increasingly important. Micro RNA (miRNA), involved in the epigenetic regulation of protein synthesis, is a biological mark which varies in association with a number of disease states, possibly including AD. Here we comprehensively review methods and findings from 26 studies comparing the measurement of miRNA in blood between AD cases and controls. Thirteen of these studies used receiver operator characteristic (ROC) analysis to determine the diagnostic accuracy of identified miRNA to predict AD, and three studies did this with a machine learning approach. Of 8098 individually measured miRNAs, 23 that were differentially expressed between AD cases and controls were found to be significant in two or more studies. Only six of these were consistent in their direction of expression between studies (miR-107, miR-125b, miR-146a, miR-181c, miR-29b, and miR-342), and they were all shown to be down regulated in individuals with AD compared to controls. Of these directionally concordant miRNAs, the strongest evidence was for miR-107 which has also been shown in previous studies to be involved in the dysregulation of proteins involved in aspects of AD pathology, as well as being consistently downregulated in studies of AD brains. We conclude that imperative to the discovery of reliable and replicable miRNA biomarkers of AD, standardised methods of measurements, appropriate statistical analysis, utilization of large datasets with machine learning approaches, and comprehensive reporting of findings is urgently needed.

Small Molecules in Rare Tumors: Emerging Role of MicroRNAs in GIST

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of gastrointestinal tract. GISTs have very different clinical phenotypes and underlying molecular characteristics that are not yet completely understood. microRNAs (miRNAs) have been shown to participate in carcinogenesis pathways through post-transcriptional regulation of gene expression in different tumors. Over the last years emerging evidence has highlighted the role of miRNAs in GISTs. This review provides an overview of original research papers that analyze miRNA deregulation patterns, functional role, diagnostic, therapeutic and prognostic implications in GIST as well as provides directions for further research in the field.