EWS/FLI1 regulates EYA3 in Ewing sarcoma via modulation of miRNA-708, resulting in increased cell survival and chemoresistance

EYA3 regulation of NF-κB and CCL2 suppresses cytotoxic NK cells in the premetastatic niche to promote TNBC metastasis

Triple-negative breast cancer cells must evade immune surveillance to metastasize to distant sites, yet this process is not well understood. The Eyes absent (EYA) family of proteins, which are crucial for embryonic development, become dysregulated in cancer, where they have been shown to mediate proliferation, migration, and invasion. Our study reveals an unusual mechanism by which EYA3 reduces the presence of cytotoxic natural killer (NK) cells in the premetastatic niche (PMN) to enhance metastasis, independent of its effects on the primary tumor. We find that EYA3 up-regulates nuclear factor κB signaling to enhance CCL2 expression, which, in contrast to previous findings, suppresses cytotoxic NK cell activation in vitro and their infiltration into the PMN in vivo. These findings uncover an unexpected role for CCL2 in inhibiting NK cell responses at the PMN and suggest that targeting EYA3 could be an effective strategy to reactivate antitumor immune responses to inhibit metastasis.

The Eyes Absent family: At the intersection of DNA repair, mitosis, and replication

The Eyes Absent family (EYA1-4) are a group of dual function proteins that act as both tyrosine phosphatases and transcriptional co-activators. EYA proteins play a vital role in development, but are also aberrantly overexpressed in cancers, where they often confer an oncogenic effect. Precisely how the EYAs impact cell biology is of growing interest, fuelled by the therapeutic potential of an expanding repertoire of EYA inhibitors. Recent functional studies suggest that the EYAs are important players in the regulation of genome maintenance pathways including DNA repair, mitosis, and DNA replication. While the characterized molecular mechanisms have predominantly been ascribed to EYA phosphatase activities, EYA co-transcriptional activity has also been found to impact the expression of genes that support these pathways. This indicates functional convergence of EYA phosphatase and co-transcriptional activities, highlighting the emerging importance of the EYA protein family at the intersection of genome maintenance mechanisms. In this review, we discuss recent progress in defining EYA protein substrates and transcriptional effects, specifically in the context of genome maintenance. We then outline future directions relevant to the field and discuss the clinical utility of EYA inhibitors.

An EYA3/NF-κB/CCL2 signaling axis suppresses cytotoxic NK cells in the pre-metastatic niche to promote triple negative breast cancer metastasis

Patients with Triple Negative Breast Cancer (TNBC) exhibit high rates of metastases and poor prognoses. The Eyes absent (EYA) family of proteins are developmental transcriptional cofactors/phosphatases that are re-expressed and/or upregulated in numerous cancers. Herein, we demonstrate that EYA3 correlates with decreased survival in breast cancer, and that it strongly, and specifically, regulates metastasis via a novel mechanism that involves NF-kB signaling and an altered innate immune profile at the pre-metastatic niche (PMN). Remarkably, restoration of NF-kB signaling downstream of Eya3 knockdown (KD) restores metastasis without restoring primary tumor growth, isolating EYA3/NF-kB effects to the metastatic site. We show that secreted CCL2, regulated downstream of EYA3/NF-kB, specifically decreases cytotoxic NK cells in the PMN and that re-expression of Ccl2 in Eya3 -KD cells is sufficient to rescue activation/levels of cytotoxic NK cells in vitro and at the PMN, where EYA3-mediated decreases in cytotoxic NK cells are required for metastatic outgrowth. Importantly, analysis of public breast cancer datasets uncovers a significant correlation of EYA3 with NF-kB/CCL2, underscoring the relevance of EYA3/NF-kB/CCL2 to human disease. Our findings suggest that inhibition of EYA3 could be a powerful means to re-activate the innate immune response at the PMN, inhibiting TNBC metastasis.

Significance

EYA3 promotes metastasis of TNBC cells by promoting NF-kB-mediated CCL2 expression and inhibiting cytotoxic NK cells at the pre-metastatic niche, highlighting a potential therapeutic target in this subset of breast cancer.

All eyes on Eya: A unique transcriptional co-activator and phosphatase in cancer

The Eya family of proteins (consisting of Eyas1-4 in mammals) play vital roles in embryogenesis by regulating processes such as proliferation, migration/invasion, cellular survival and pluripotency/plasticity of epithelial and mesenchymal states. Eya proteins carry out such diverse functions through a unique combination of transcriptional co-factor, Tyr phosphatase, and PP2A/B55α-mediated Ser/Thr phosphatase activities. Since their initial discovery, re-expression of Eyas has been observed in numerous tumor types, where they are known to promote tumor progression through a combination of their transcriptional and enzymatic activities. Eya proteins thus reinstate developmental processes during malignancy and represent a compelling class of therapeutic targets for inhibiting tumor progression.

In Vitro Phosphatase Assays for the Eya2 Tyrosine Phosphatase

Protein tyrosine phosphatases (PTP), such as the Eyes Absent (Eya) family of proteins, play important roles in diverse biological processes. In vitro phosphatase assays are essential tools for characterizing the enzymatic activity as well as discovering inhibitors and regulators of these phosphatases. Two common types of in vitro phosphatase assays use either a small molecule substrate that produces a fluorescent or colored product, or a peptide substrate that produces a colorimetric product in a malachite green assay. In this chapter, we describe detailed protocols of a phosphatase assay using small molecule 3-O-methylfluorescein phosphate (OMFP) as a substrate and a malachite green assay using the pH2AX peptide as a substrate to evaluate the phosphatase activity of EYA2 and the effect of small molecule inhibitors of EYA2. These protocols can be easily adapted to study other protein tyrosine phosphatases.

Oncomeric Profiles of microRNAs as New Therapeutic Targets for Treatment of Ewing's Sarcoma: A Composite Review

Ewing's sarcoma is a rare type of cancer that forms in bones and soft tissues in the body, affecting mostly children and young adults. Current treatments for ES are limited to chemotherapy and/or radiation, followed by surgery. Recently, microRNAs have shown favourable results as latent diagnostic and prognostic biomarkers in various cancers. Furthermore, microRNAs have shown to be a good therapeutic agent due to their involvement in the dysregulation of various molecular pathways linked to tumour progression, invasion, angiogenesis, and metastasis. In this review, comprehensive data mining was employed to explore various microRNAs that might have therapeutic potential as target molecules in the treatment of ES.

Targeted Therapy for EWS-FLI1 in Ewing Sarcoma

Ewing sarcoma (EwS) is a rare and predominantly pediatric malignancy of bone and soft tissue in children and adolescents. Although international collaborations have greatly improved the prognosis of most EwS, the occurrence of macrometastases or relapse remains challenging. The prototypic oncogene EWS-FLI1 acts as an aberrant transcription factor that drives the cellular transformation of EwS. In addition to its involvement in RNA splicing and the DNA damage response, this chimeric protein directly binds to GGAA repeats, thereby modifying the transcriptional profile of EwS. Direct pharmacological targeting of EWS-FLI1 is difficult because of its intrinsically disordered structure. However, targeting the EWS-FLI1 protein complex or downstream pathways provides additional therapeutic options. This review describes the EWS-FLI1 protein partners and downstream pathways, as well as the related target therapies for the treatment of EwS.

The value of EYA1/3/4 in clear cell renal cell carcinoma: a study from multiple databases

There is evidence from multiple studies that dysregulation of the Eyes Absent (EYA) protein plays multiple roles in many cancers. Despite this, little is known about the prognostic significance of the EYAs family in clear cell renal cell carcinoma (ccRCC). We systematically analyzed the value of EYAs in Clear Cell Renal Cell Carcinoma. Our analysis included examining transcriptional levels, mutations, methylated modifications, co-expression, protein-protein interactions (PPIs), immune infiltration, single-cell sequencing, drug sensitivity, and prognostic values. We based our analysis on data from several databases, including the Cancer Genome Atlas database (TCGA), the Gene Expression Omnibus database (GEO), UALCAN, TIMER, Gene Expression Profiling Interactive Analysis (GEPIA), STRING, cBioPortal and GSCALite. In patients with ccRCC, the EYA1 gene was significantly highly expressed, while the expression of EYA2/3/4 genes showed the opposite trend. The level of expression of the EYA1/3/4 gene was significantly correlated with the prognosis and clinicopathological parameters of ccRCC patients. Univariate and multifactorial Cox regression analyses revealed EYA1/3 as an independent prognostic factor for ccRCC, establishing nomogram line plots with good predictive power. Meanwhile, the number of mutations in EYAs was also significantly correlated with poor overall survival (OS) and progression-free survival (PFS) of patients with ccRCC. Mechanistically, EYAs genes play an essential role in a wide range of biological processes such as DNA metabolism and double-strand break repair in ccRCC. The majority of EYAs members were related to the infiltration of immune cells, drug sensitivity, and methylation levels. Furthermore, our experiment confirmed that EYA1 gene expression was upregulated, and EYA2/3/4 showed low expression in ccRCC. The increased expression of EYA1 might play an important role in ccRCC oncogenesis, and the decreased expression of EYA3/4 could function as a tumor suppressor, suggesting EYA1/3/4 might serve as valuable prognostic markers and potential new therapeutic targets for ccRCC.

The Double Face of miR-708: A Pan-Cancer Player with Dissociative Identity Disorder

Over the last decades, accumulating evidence has shown tumor-dependent profiles of miR-708, being either up- or downregulated, and thus, acting as a "Janus" regulator of oncogenic pathways. Herein, its functional duality was assessed through a thorough review of the literature and further validation in silico using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. In the literature, miR-708 was found with an oncogenic role in eight tumor types, while a suppressor tumor role was described in seven cancers. This double profile was also found in TCGA and GEO databases, with some tumor types having a high expression of miR-708 and others with low expression compared with non-tumor counterparts. The investigation of validated targets using miRBase, miRTarBase, and miRecords platforms, identified a total of 572 genes that appeared enriched for PI3K-Akt signaling, followed by cell cycle control, p53, Apellin and Hippo signaling, endocrine resistance, focal adhesion, and cell senescence regulations, which are all recognized contributors of tumoral phenotypes. Among these targets, a set of 15 genes shared by at least two platforms was identified, most of which have important roles in cancer cells that influence either tumor suppression or progression. In a clinical scenario, miR-708 has shown to be a good diagnostic and prognosis marker. However, its multitarget nature and opposing roles in diverse human tumors, aligned with insufficient experimental data and the lack of proper delivery strategies, hamper its potential as a sequence-directed therapeutic.

The clinical utility of dysregulated microRNA expression in paediatric solid tumours

MicroRNAs (miRNAs) are short, non-protein-coding genes that regulate the expression of numerous protein-coding genes. Their expression is dysregulated in cancer, where they may function as oncogenes or tumour suppressor genes. As miRNAs are highly resistant to degradation, they are ideal biomarker candidates to improve the diagnosis and clinical management of cancer, including prognostication. Furthermore, miRNAs dysregulated in malignancy represent potential therapeutic targets. The use of miRNAs for these purposes is a particularly attractive option to explore for paediatric malignancies, where the mutational burden is typically low, in contrast to cancers affecting adult patients. As childhood cancers are rare, it has taken time to accumulate the necessary body of evidence showing the potential for miRNAs to improve clinical management across this group of tumours. Here, we review the current literature regarding the potential clinical utility of miRNAs in paediatric solid tumours, which is now both timely and justified. Exploring such avenues is warranted to improve the management and outcomes of children affected by cancer.

Epi-miRNAs: Regulators of the Histone Modification Machinery in Human Cancer

Cancer is a leading cause of death and disability worldwide. Epigenetic deregulation is one of the most critical mechanisms in carcinogenesis and can be classified into effects on DNA methylation and histone modification. MicroRNAs are small noncoding RNAs involved in fine-tuning their target genes after transcription. Various microRNAs control the expression of histone modifiers and are involved in a variety of cancers. Therefore, overexpression or downregulation of microRNAs can alter cell fate and cause malignancies. In this review, we discuss the role of microRNAs in regulating the histone modification machinery in various cancers, with a focus on the histone-modifying enzymes such as acetylases, deacetylases, methyltransferases, demethylases, kinases, phosphatases, desumoylases, ubiquitinases, and deubiquitinases. Understanding of microRNA-related aberrations underlying histone modifiers in pathogenesis of different cancers can help identify novel therapeutic targets or early detection approaches that allow better management of patients or monitoring of treatment response.

Role and Involvement of TENM4 and miR-708 in Breast Cancer Development and Therapy

Teneurin 4 (TENM4) is a transmembrane protein that is codified by the ODZ4 gene and is involved in nervous system development, neurite outgrowth, and neuronal differentiation. In line with its involvement in the nervous system, TENM4 has also been implicated in several mental disorders such as bipolar disorder, schizophrenia, and autism. TENM4 mutations and rearrangements have recently been identified in a number of tumors. This, combined with impaired expression in tumors, suggests that it may potentially be involved in tumorigenesis. Most of the TENM4 mutations that are observed in tumors occur in breast cancer, in which TENM4 plays a role in cells’ migration and stemness. However, the functional role that TENM4 plays in breast cancer still needs to be better evaluated, and further studies are required to better understand the involvement of TENM4 in breast cancer progression. Herein, we review the currently available data for TENM4′s role in breast cancer and propose its use as both a novel target with which to ameliorate patient prognosis and as a potential biomarker. Moreover, we also report data on the tumorigenic role of miR-708 deregulation and the possible use of this miRNA as a novel therapeutic molecule, as miR-708 is spliced out from TENM4 mRNA.

Challenges in modeling EWS-FLI1-driven transgenic mouse model for Ewing sarcoma

EWS-FLI1 is a master regulator of Ewing sarcoma (ES) oncogenesis. Although EWS-FLI1 represents a clear therapeutic target, targeted therapeutic inhibitors are lacking. Scientific literature has indicated accumulating information pertaining to EWS-FLI1 translocation, pathogenesis, function, oncogenic partnerships, and potential clinical relevance. However, attempts to develop EWS-FLI1-driven human-like ES mouse models or in vivo systems ended up with limited success. Establishing such models as preclinical screening tools may accelerate the development of EWS-FLI1 targeted therapeutic inhibitors. This review summarizes the current scenario, which focuses on the limitations, challenges, and possible reasons for past failures in model development and also plausible interim alternatives.

Targeting EYA2 tyrosine phosphatase activity in glioblastoma stem cells induces mitotic catastrophe

Glioblastoma ranks among the most lethal of primary brain malignancies, with glioblastoma stem cells (GSCs) at the apex of tumor cellular hierarchies. Here, to discover novel therapeutic GSC targets, we interrogated gene expression profiles from GSCs, differentiated glioblastoma cells (DGCs), and neural stem cells (NSCs), revealing EYA2 as preferentially expressed by GSCs. Targeting EYA2 impaired GSC maintenance and induced cell cycle arrest, apoptosis, and loss of self-renewal. EYA2 displayed novel localization to centrosomes in GSCs, and EYA2 tyrosine (Tyr) phosphatase activity was essential for proper mitotic spindle assembly and survival of GSCs. Inhibition of the EYA2 Tyr phosphatase activity, via genetic or pharmacological means, mimicked EYA2 loss in GSCs in vitro and extended the survival of tumor-bearing mice. Supporting the clinical relevance of these findings, EYA2 portends poor patient prognosis in glioblastoma. Collectively, our data indicate that EYA2 phosphatase function plays selective critical roles in the growth and survival of GSCs, potentially offering a high therapeutic index for EYA2 inhibitors.

The Landscape of Regulatory Noncoding RNAs in Ewing's Sarcoma

Ewing's sarcoma (ES) is a pediatric sarcoma caused by a chromosomal translocation. Unlike in most cancers, the genomes of ES patients are very stable. The translocation product of the EWS-FLI1 fusion is most often the predominant genetic driver of oncogenesis, and it is pertinent to explore the role of epigenetic alterations in the onset and progression of ES. Several types of noncoding RNAs, primarily microRNAs and long noncoding RNAs, are key epigenetic regulators that have been shown to play critical roles in various cancers. The functions of these epigenetic regulators are just beginning to be appreciated in ES. Here, we performed a comprehensive literature review to identify these noncoding RNAs. We identified clinically relevant tumor suppressor microRNAs, tumor promoter microRNAs and long noncoding RNAs. We then explored the known interplay between different classes of noncoding RNAs and described the currently unmet need for expanding the noncoding RNA repertoire of ES. We concluded the review with a discussion of epigenetic regulation of ES via regulatory noncoding RNAs. These noncoding RNAs provide new avenues of exploration to develop better therapeutics and identify novel biomarkers.

Targeting EYA3 in Ewing Sarcoma Retards Tumor Growth and Angiogenesis

EWSR1/FLI1, the most common fusion gene in Ewing sarcoma, upregulates expression of the Eyes Absent 3 (EYA3) transactivator-phosphatase protein. The purpose of this study was to investigate molecular and cellular mechanisms through which EYA3 might promote Ewing sarcoma tumor growth and to determine whether the EYA3 tyrosine phosphatase activity represents a viable therapeutic target. We used genetic and pharmacologic modulation of EYA3 in cell line-based xenografts to examine how loss of EYA3 tyrosine phosphatase activity affects tumor growth and angiogenesis. Molecular mechanisms were evaluated in vivo and in vitro through analyses of tumor tissue and multicellular tumor spheroids. Our results show that both loss of EYA3 in Ewing sarcoma cells and pharmacologic inhibition of the EYA3 tyrosine phosphatase activity inhibit tumor growth and tumor angiogenesis. EYA3 regulates levels of VEGFA in Ewing tumors, as well as promoting DNA damage repair and survival of Ewing sarcoma tumor cells. Target engagement is demonstrated in tumor tissue through elevated levels of the EYA3 substrate H2AX-pY142 upon loss of EYA3 or with Benzarone treatment. The efficacy of EYA3 tyrosine phosphatase inhibition in attenuating tumor growth and angiogenesis is corroborated in an Ewing sarcoma patient-derived tumor xenograft. Together, the results presented here validate EYA3 as a target for the development of novel Ewing sarcoma therapeutic strategies, and set the stage for evaluating the efficacy of combining the antiangiogenic and anti-cell survival effects of EYA3 inhibition with cytotoxic chemotherapy.

EYA2 upregulates miR-93 to promote tumorigenesis of breast cancer by targeting and inhibiting the STING signaling pathway

Herein, we used DIANA TOOLS, GEPIA and other bioinformatics databases to predict regulatory pathways in breast cancer. Accordingly, we clarified the regulatory mechanism of EYA2 on miR-93 expression to aggravate breast cancer, which was involved with the STING signaling pathway. CCK-8 assay, scratch test, Transwell assay, and flow cytometry were applied to detect cell viability, migration, invasion, and apoptosis. The experimental data found that EYA2 was highly expressed in breast cancer tissues and cells and associated with poor prognosis. Overexpression of miR-93 in breast cancer was positively correlated with EYA2. EYA2 promoted miR-93 expression, advanced breast cancer cell proliferation and inhibited their apoptosis. Results of luciferase assay showed that miR-93 was enriched in the STING 3'UTR. Furthermore, knockdown of EYA2 inhibited the expression of miR-93, promoted the expression of STING, and inhibited the tumor growth. In response to EYA2 knockdown, the expression of IFN-β and ISG was increased, and PD-L1 was decreased. In addition, the phosphorylation level of TBK1 and IRF3 was enhanced, the percentage of myeloid-derived suppressor cells in blood was reduced, and secretion of IFN-β and IL-12 was enhanced. In conclusion, EYA2 upregulates miR-93 expression and promotes malignancy of breast cancer by targeting and inhibiting the STING signaling pathway.

A Novel 10-Gene Signature Predicts Poor Prognosis in Low Grade Glioma

AIM

Low grade glioma (LGG) is a lethal brain cancer with relatively poor prognosis in young adults. Thus, this study was performed to develop novel molecular biomarkers to effectively predict the prognosis of LGG patients and finally guide treatment decisions.

METHODS

survival-related genes were determined by Kaplan-Meier survival analysis and multivariate Cox regression analysis using the expression and clinical data of 506 LGG patients from The Cancer Genome Atlas (TCGA) database and independently validated in a Chinese Glioma Genome Atlas (CGGA) dataset. A prognostic risk score was established based on a linear combination of 10 gene expression levels using the regression coefficients of the multivariate Cox regression models. GSEA was performed to analyze the altered signaling pathways between the high and low risk groups stratified by median risk score.

RESULTS

We identified a total of 1489 genes significantly correlated with patients' prognosis in LGG. The top 5 protective genes were DISP2, CKMT1B, AQP7, GPR162 and CHGB, the top 5 risk genes were SP1, EYA3, ZSCAN20, ITPRIPL1 and ZNF217 in LGG. The risk score was predictive of poor overall survival and relapse-free survival in LGG patients. Pathways of small cell lung cancer, pathways in cancer, chronic myeloid leukemia, colorectal cancer were the top 4 most enriched pathways in the high risk group. SP1, EYA3, ZSCAN20, ITPRIPL1, ZNF217 and GPR162 were significantly up-regulated, while DISP2, CKMT1B, AQP7 were down-regulated in 523 LGG tissues as compared to 1141 normal brain controls.

CONCLUSIONS

The 10-gene signature may become novel prognostic and diagnostic biomarkers to considerably improve the prognostic prediction in LGG.

The multi-functional eyes absent proteins

The Eyes Absent (EYA) proteins are the only known instance of a single polypeptide housing the following three separable biochemical activities: tyrosine phosphatase, threonine phosphatase, and transactivation. This uniquely positions the EYAs to participate in both transcriptional regulation and signal transduction pathways. But it also complicates the assignment of biological roles to individual biochemical activities through standard loss-of-function experiments. Nevertheless, there is an emerging literature linking developmental and pathological functions with the various EYA activities, and a growing list of disease states that might benefit from EYA-targeted therapeutics. There also remain multiple unresolved issues with significant implications for our understanding of how the EYAs might impact such ubiquitous signaling cascades as the MYC and Notch pathways. This review will describe the unique juxtaposition of biochemical activities in the EYAs, their interaction with signaling pathways and cellular processes, emerging evidence of roles in disease states, and the feasibility of therapeutic targeting of individual EYA activities. We will focus on the phosphatase activities of the vertebrate EYA proteins and will examine the current state of knowledge regarding: • substrates and signaling pathways affected by the EYA tyrosine phosphatase activity; • modes of regulation of the EYA tyrosine phosphatase activity; • signaling pathways that implicate the threonine phosphatase activity of the EYAs including a potential interaction with PP2A-B55α; • the interplay between the two phosphatase activities and the transactivation function of the EYAs; • disease states associated with the EYAs and the current state of development of EYA-targeted therapeutics.

miR-708-5p targets oncogenic prostaglandin E2 production to suppress a pro-tumorigenic phenotype in lung cancer cells

Many cancers maintain an inflammatory microenvironment to promote their growth. Lung cancer is of particular importance, as it is the deadliest cancer worldwide. One inflammatory pathway commonly dysregulated in cancer is the metabolism of arachidonic acid (AA) by Cyclooxygenase-2 (COX-2) and microsomal Prostaglandin E Synthase 1 (mPGES-1) into Prostaglandin E2 (PGE2). While researchers have identified PGE2's pro-tumorigenic functions, the mechanisms governing overexpression of COX-2 and mPGES-1 are incompletely understood. MicroRNAs (miRNAs) are important post-transcriptional regulators commonly dysregulated in cancer. Interestingly, miR-708-5p (miR-708) is predicted to target both COX-2 and mPGES-1. In this study, we show that high miR-708 expression is associated with survival rates in lung squamous cell carcinoma patients. miR-708 also represses PGE2 production by suppressing both COX-2 and mPGES-1 expression in lung cancer cells. miR-708 regulation of COX-2 and mPGES-1 is mediated through targeting of their 3' untranslated regions (UTRs). Moreover, miR-708 decreases proliferation, survival, and migration of lung cancer cells, which can be partially attributed to miR-708's inhibition of PGE2 signaling. Lastly, we identify novel miR-708 predicted targets and possible regulators of miR-708 expression in lung cancer. Collectively, these data demonstrate that dysregulated miR-708 expression contributes to exacerbated PGE2 production, leading to an enhanced pro-tumorigenic phenotype in lung cancer cells.

Understanding the Mechanisms by Which Epigenetic Modifiers Avert Therapy Resistance in Cancer

The development of resistance to anti-cancer therapeutics remains one of the core issues preventing the improvement of survival rates in cancer. Therapy resistance can arise in a multitude of ways, including the accumulation of epigenetic alterations in cancer cells. By remodeling DNA methylation patterns or modifying histone proteins during oncogenesis, cancer cells reorient their epigenomic landscapes in order to aggressively resist anti-cancer therapy. To combat these chemoresistant effects, epigenetic modifiers such as DNA hypomethylating agents, histone deacetylase inhibitors, histone demethylase inhibitors, along with others have been used. While these modifiers have achieved moderate success when used either alone or in combination with one another, the most positive outcomes were achieved when they were used in conjunction with conventional anti-cancer therapies. Epigenome modifying drugs have succeeded in sensitizing cancer cells to anti-cancer therapy via a variety of mechanisms: disrupting pro-survival/anti-apoptotic signaling, restoring cell cycle control and preventing DNA damage repair, suppressing immune system evasion, regulating altered metabolism, disengaging pro-survival microenvironmental interactions and increasing protein expression for targeted therapies. In this review, we explore different mechanisms by which epigenetic modifiers induce sensitivity to anti-cancer therapies and encourage the further identification of the specific genes involved with sensitization to facilitate development of clinical trials.

MicroRNA-708 Suppresses Cell Proliferation and Enhances Chemosensitivity of Cervical Cancer Cells to cDDP by Negatively Targeting Timeless

Purpose

Cervical cancer is the fourth most common cause of cancer-associated mortality in women worldwide. Previous studies have reported that microRNAs (miRNAs) are involved in multiple biological aspects of cancer progression by regulating gene expression. Here, we investigated the role of microRNA-708 (miR-708) in cervical cancer.

Methods

The expression levels of miR-708 in cervical cancer tissues and paired-normal cervical tissues were tested by quantitative polymerase chain reaction (qPCR). The interaction between miR-708 and Timeless was identified by bioinformatics method, dual-luciferase reporter assay, and Western blotting. The effects of over-expression of miR-708 on cell proliferation and cisplatin sensitivity were determined by Cell Counting Kit-8 (CCK-8) and colony formation assay. Cell cycle and apoptosis were analyzed by flow cytometry. DNA damage induced by over-expression of miR-708 was determined by comet assay. Expression levels of the genes involved in repair of DNA damage were analyzed by Western blotting.

Results

MiR-708 was down-regulated in cervical cancer tissues compared with paired-normal cervical tissues. By bioinformatics method, Western blotting, and dual-luciferase reporter assay, we found that Timeless was a direct target of miR-708. Furthermore, miR-708 suppressed cellular viability, colony formation, promoted apoptosis, and induced DNA damage levels. MiR-708 also enhanced chemosensitivity of cervical cancer cells to cDDP via impairing the ATR/CHK1 signaling pathway.

Conclusion

We conclude that miR-708 suppresses cell proliferation, facilitates cisplatin efficacy, and impairs DNA repair pathway in cervical cancer cells. These results demonstrate that miR-708 might be a candidate therapeutic target for future cervical cancer therapy.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

Non-Coding RNAs in Pediatric Solid Tumors

Pediatric solid tumors are a diverse group of extracranial solid tumors representing approximately 40% of childhood cancers. Pediatric solid tumors are believed to arise as a result of disruptions in the developmental process of precursor cells which lead them to accumulate cancerous phenotypes. In contrast to many adult tumors, pediatric tumors typically feature a low number of genetic mutations in protein-coding genes which could explain the emergence of these phenotypes. It is likely that oncogenesis occurs after a failure at many different levels of regulation. Non-coding RNAs (ncRNAs) comprise a group of functional RNA molecules that lack protein coding potential but are essential in the regulation and maintenance of many epigenetic and post-translational mechanisms. Indeed, research has accumulated a large body of evidence implicating many ncRNAs in the regulation of well-established oncogenic networks. In this review we cover a range of extracranial solid tumors which represent some of the rarer and enigmatic childhood cancers known. We focus on two major classes of ncRNAs, microRNAs and long non-coding RNAs, which are likely to play a key role in the development of these cancers and emphasize their functional contributions and molecular interactions during tumor formation.

The EYA3 tyrosine phosphatase activity promotes pulmonary vascular remodeling in pulmonary arterial hypertension

In pulmonary hypertension vascular remodeling leads to narrowing of distal pulmonary arterioles and increased pulmonary vascular resistance. Vascular remodeling is promoted by the survival and proliferation of pulmonary arterial vascular cells in a DNA-damaging, hostile microenvironment. Here we report that levels of Eyes Absent 3 (EYA3) are elevated in pulmonary arterial smooth muscle cells from patients with pulmonary arterial hypertension and that EYA3 tyrosine phosphatase activity promotes the survival of these cells under DNA-damaging conditions. Transgenic mice harboring an inactivating mutation in the EYA3 tyrosine phosphatase domain are significantly protected from vascular remodeling. Pharmacological inhibition of the EYA3 tyrosine phosphatase activity substantially reverses vascular remodeling in a rat model of angio-obliterative pulmonary hypertension. Together these observations establish EYA3 as a disease-modifying target whose function in the pathophysiology of pulmonary arterial hypertension can be targeted by available inhibitors.

Relevance function of microRNA-708 in the pathogenesis of cancer

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression post-transcriptionally responsible for regulating >70% of human genes. MicroRNA-708 (miR-708) is encoded in the intron 1 of the Odd Oz/ten-m homolog 4 (ODZ4) gene. Numerous researches have confirmed that the abnormal expressed miR-708 is involved in the regulation of multiple types of cancer. Notably, the expression level of miR-708 was higher in lung cancer, bladder cancer (BC) and colorectal cancer (CRC) cell lines while lower in hepatocellular carcinoma (HCC), prostate cancer (PC), gastric cancer (GC) and so on. This review provides a current view on the association between miR-708 and several cancers and focuses on the recent studies of miR-708 regulation, discussing its potential as an epigenetic biomarker and therapeutic target for these cancers. In particular, the regulated mechanisms and clinical application of miR-708 in these cancers are also discussed.

Structural and Functional Analyses of an Allosteric EYA2 Phosphatase Inhibitor That Has On-Target Effects in Human Lung Cancer Cells

EYA proteins (EYA1-4) are critical developmental transcriptional cofactors that contain an EYA domain (ED) harboring Tyr phosphatase activity. EYA proteins are largely downregulated after embryogenesis but are reexpressed in cancers, and their Tyr phosphatase activity plays an important role in the DNA damage response and tumor progression. We previously identified a class of small-molecule allosteric inhibitors that specifically inhibit the Tyr phosphatase activity of EYA2. Herein, we determined the crystal structure of the EYA2 ED in complex with NCGC00249987 (a representative compound in this class), revealing that it binds to an induced pocket distant from the active site. NCGC00249987 binding leads to a conformational change of the active site that is unfavorable for Mg²⁺ binding, thereby inhibiting EYA2's Tyr phosphatase activity. We demonstrate, using genetic mutations, that migration, invadopodia formation, and invasion of lung adenocarcinoma cells are dependent on EYA2 Tyr phosphatase activity, whereas growth and survival are not. Further, we demonstrate that NCGC00249987 specifically targets migration, invadopodia formation, and invasion of lung cancer cells, but that it does not inhibit cell growth or survival. The compound has no effect on lung cancer cells carrying an EYA2 F290Y mutant that abolishes compound binding, indicating that NCGC00249987 is on target in lung cancer cells. These data suggest that the NCGC00249987 allosteric inhibitor can be used as a chemical probe to study the function of the EYA2 Tyr phosphatase activity in cells and may have the potential to be developed into an antimetastatic agent for cancers reliant on EYA2's Tyr phosphatase activity.

Diversified Application of Barcoded PLATO (PLATO-BC) Platform for Identification of Protein Interactions

Proteins usually associate with other molecules physically to execute their functions. Identifying these interactions is important for the functional analysis of proteins. Previously, we reported the parallel analysis of translated ORFs (PLATO) to couple ribosome display of full-length ORFs with affinity enrichment of mRNA/protein/ribosome complexes for the "bait" molecules, followed by the deep sequencing analysis of mRNA. However, the sample processing, from extraction of precipitated mRNA to generation of DNA libraries, includes numerous steps, which is tedious and may cause the loss of materials. Barcoded PLATO (PLATO-BC), an improved platform was further developed to test its application for protein interaction discovery. In this report, we tested the antisera-antigen interaction using serum samples from patients with inclusion body myositis (IBM). Tripartite motif containing 21 (TRIM21) was identified as a potentially new IBM autoantigen. We also expanded the application of PLATO-BC to identify protein interactions for JQ1, single ubiquitin peptide, and NS5 protein of Zika virus. From PLATO-BC analyses, we identified new protein interactions for these "bait" molecules. We demonstrate that Ewing sarcoma breakpoint region 1 (EWSR1) binds to JQ1 and their interactions may interrupt the EWSR1 association with acetylated histone H4. RIO kinase 3 (RIOK3), a newly identified ubiquitin-binding protein, is preferentially associated with K63-ubiquitin chain. We also find that Zika NS5 protein interacts with two previously unreported host proteins, par-3 family cell polarity regulator (PARD3) and chromosome 19 open reading frame 53 (C19orf53), whose attenuated expression benefits the replication of Zika virus. These results further demonstrate that PLATO-BC is capable of identifying novel protein interactions for various types of "bait" molecules.

An Insight into the Roles of MicroRNAs and Exosomes in Sarcoma

Sarcomas are rare solid tumors, but at least one-third of patients with sarcoma die from tumor-related disease. MicroRNA (miRNA) is a noncoding RNA that regulates gene expression in all cells and plays a key role in the progression of cancers. Recently, it was identified that miRNAs are transferred between cells by enclosure in extracellular vesicles, especially exosomes. The exosome is a 100 nm-sized membraned vesicle that is secreted by many kinds of cells and contains miRNA, mRNA, DNA, and proteins. Cancer uses exosomes to influence not only the tumor microenvironment but also the distant organ to create a premetastatic niche. The progression of sarcoma is also regulated by miRNAs and exosomes. These miRNAs and exosomes can be targeted as biomarkers and treatments. In this review, we summarize the studies of miRNA and exosomes in sarcoma.

Regulation of cancer stem cell properties by SIX1, a member of the PAX-SIX-EYA-DACH network

The PAX-SIX-EYA-DACH network (PSEDN) is a central developmental transcriptional regulatory network from Drosophila to humans. The PSEDN is comprised of four conserved protein families; including paired box (PAX), sine oculis (SIX), eyes absent (EYA), and dachshund (DACH). Aberrant expression of PSEDN members, particularly SIX1, has been observed in multiple human cancers, where SIX1 expression correlates with increased aggressiveness and poor prognosis. In conjunction with its transcriptional activator EYA, the SIX1 transcription factor increases cancer stem cell (CSC) numbers and induces epithelial-mesenchymal transition (EMT). SIX1 promotes multiple hallmarks and enabling characteristics of cancer via regulation of cell proliferation, senescence, apoptosis, genome stability, and energy metabolism. SIX1 also influences the tumor microenvironment, enhancing recruitment of tumor-associated macrophages and stimulating angiogenesis, to promote tumor development and progression. EYA proteins are multifunctional, possessing a transcriptional activation domain and tyrosine phosphatase activity, that each contributes to cancer stem cell properties. DACH proteins function as tumor suppressors in solid cancers, opposing the actions of SIX-EYA and reducing CSC prevalence. Multiple mechanisms can lead to increased SIX1 expression, including loss of SIX1-targeting tumor suppressor microRNAs (miRs), whose expression correlates inversely with SIX1 expression in cancer patient samples. In this review, we discuss the major mechanisms by which SIX1 confers CSC and EMT features and other important cancer cell characteristics. The roles of EYA and DACH in CSCs and cancer progression are briefly highlighted. Finally, we summarize the clinical significance of SIX1 in cancer to emphasize the potential therapeutic benefits of effective strategies to disrupt PSEDN protein interactions and functions.

MicroRNAs and breast cancer stem cells: Potential role in breast cancer therapy

MicroRNAs (miRNAs) can control cancer and cancer stem cells (CSCs), and this topic has drawn immense attention recently. Stem cells are a tiny population of a bulk of tumor cells that have enormous potential in expansion and metastasis of the tumor. miRNA have a crucial role in the management of the function of stem cells. This role is to either promote or suppress the tumor. In this review, we investigated the function and different characteristics of CSCs and function of the miRNAs that are related to them. We also demonstrated the role and efficacy of these miRNAs in breast cancer and breast cancer stem cells (BCSC). Eventually, we revealed the metastasis, tumor formation, and their role in the apoptosis process. Also, the therapeutic potential of miRNA as an effective method for the treatment of BCSC was described. Extensive research is required to investigate the employment or suppression of these miRNAs for therapeutics approached in different cancers in the future.

MicroRNA‑34b promotes proliferation, migration and invasion of Ewing's sarcoma cells by downregulating Notch1

Ewing's sarcoma is the second most frequent bone and soft tissue sarcoma, which is commonly driven by the Ewing's sarcoma breakpoint region 1-friend leukemia integration 1 transcription factor (EWS-FLI1) fusion gene. Since microRNAs (miRs) can act as either oncogenes or tumor suppressor genes in human cancer, and miR-34b has been reported to act as a tumor suppressor, the role of miR-34b in Ewing's sarcoma was investigated in the present study. The results demonstrated that miR-34b expression levels were higher in tumor samples compared within normal tissue samples. Notably, miR-34b expression levels were significantly higher in EWS-FLI1-positive samples compared within EWS-FLI1-negative samples. The effects of miR-34b expression on cell proliferation, migration and invasion were also examined. miR-34b expression was inhibited using small interfering (si)RNA targeting the fusion gene. Transfection of a miR-34b precursor sequence into siRNA-treated tumor cells resulted in a significant increase in cell growth, migration and invasion compared within the control group. In addition, the adhesive ability was increased in the Ewing's sarcoma cell line RD-ES, but not A673, following miR-34b upregulation. Conversely, downregulation of miR-34b expression led to a significant decrease in cell growth, migration and invasion. Notch has previously been reported to serve either oncogenic or tumor suppressive roles in human cancer. The results indicated that Notch1 and its target genes, Hes family BHLH transcription factor 1 and Hes-related family BHLH transcription factor with YRPW motif 1, were suppressed by miR-34b directly In conclusion, EWS-FLI1 may modulate miR-34b expression directly or indirectly, and miR-34b potentially has an oncogenic role in Ewing's sarcoma by downregulating Notch1.

The Protein Tyrosine Phosphatase Activity of Eyes Absent Contributes to Tumor Angiogenesis and Tumor Growth

DNA damage repair capacity is required for cells to survive catastrophic DNA damage and proliferate under conditions of intratumoral stress. The ability of the minor histone protein H2AX to serve as a hub for the assembly of a productive DNA damage repair complex is a necessary step in preventing DNA damage-induced cell death. The Eyes Absent (EYA) proteins dephosphorylate the terminal tyrosine residue of H2AX, thus permitting assembly of a productive DNA repair complex. Here, we use genetic and chemical biology approaches to separately query the roles of host vascular endothelial cell and tumor cell EYA in tumor growth. Deletion of Eya3 in host endothelial cells significantly reduced tumor angiogenesis and limited tumor growth in xenografts. Deletion of Eya3 in tumor cells reduced tumor cell proliferation and tumor growth without affecting tumor angiogenesis. A chemical inhibitor of the EYA tyrosine phosphatase activity inhibited both tumor angiogenesis and tumor growth. Simultaneously targeting the tumor vasculature and tumor cells is an attractive therapeutic strategy because it could counter the development of the more aggressive phenotype known to emerge from conventional antiangiogenic agents. Mol Cancer Ther; 17(8); 1659-69. ©2018 AACR.

Inhibition of LCMR1 and ATG12 by demethylation-activated miR-570-3p is involved in the anti-metastasis effects of metformin on human osteosarcoma

Epidemiological studies have demonstrated that metformin could mitigate the progression of several tumors. Although it has been proved that metformin could cause demethylation of DNA and lead to up-regulation of some encoding genes and non-coding RNAs, there is little data about the effects of metformin on metastasis, and the interaction between metastasis and autophagy in human osteosarcoma cells. Here, we found miR-570-3p was significantly down-regulated in human metastatic osteosarcoma tissues but not in non-metastatic osteosarcoma tissues. Metformin attenuates the metastasis and autophagy in osteosarcoma. Interestingly, this autophagy favors osteosarcoma cells invasion. Moreover, reduction of metformin-induced inhibition of autophagy could reverse the invasion suppression in osteosarcoma. Mechanistically, metformin increases miR-570-3p by the demethylation of DNA, and the upregulation of miR-570-3p repressed the translation of its target, LCMR1 and ATG12. Our results, for the first time, presents evidence that the miR-570-3p-mediated suppression of LCMR1 and ATG12 is involved in the metformin-induced inhibition of metastasis in osteosarcoma cells.

Eya3 promotes breast tumor-associated immune suppression via threonine phosphatase-mediated PD-L1 upregulation

Eya proteins are critical developmental regulators that are highly expressed in embryogenesis but downregulated after development. Amplification and/or re-expression of Eyas occurs in many tumor types. In breast cancer, Eyas regulate tumor progression by acting as transcriptional cofactors and tyrosine phosphatases. Intriguingly, Eyas harbor a separate threonine (Thr) phosphatase activity, which was previously implicated in innate immunity. Here we describe what we believe to be a novel role for Eya3 in mediating triple-negative breast cancer-associated immune suppression. Eya3 loss decreases tumor growth in immune-competent mice and is associated with increased numbers of infiltrated CD8+ T cells, which, when depleted, reverse the effects of Eya3 knockdown. Mechanistically, Eya3 utilizes its Thr phosphatase activity to dephosphorylate Myc at pT58, resulting in a stabilized form. We show that Myc is required for Eya3-mediated increases in PD-L1, and that rescue of PD-L1 in Eya3-knockdown cells restores tumor progression. Finally, we demonstrate that Eya3 significantly correlates with PD-L1 in human breast tumors, and that tumors expressing high levels of Eya3 have a decreased CD8+ T cell signature. Our data uncover a role for Eya3 in mediating tumor-associated immune suppression, and suggest that its inhibition may enhance checkpoint therapies.

miR-708-5p: a microRNA with emerging roles in cancer

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression post-transcriptionally. They are crucial for normal development and maintaining homeostasis. Researchers have discovered that dysregulated miRNA expression contributes to many pathological conditions, including cancer. miRNAs can augment or suppress tumorigenesis based on their expression and transcribed targetome in various cell types. In recent years, researchers have begun to identify miRNAs commonly dysregulated in cancer. One recently identified miRNA, miR-708-5p, has been shown to have profound roles in promoting or suppressing oncogenesis in a myriad of solid and hematological tumors. This review highlights the diverse, sometimes controversial findings reported for miR-708-5p in cancer, and the importance of further exploring this exciting miRNA.

The Eya phosphatase: Its unique role in cancer

The Eya proteins were originally identified as essential transcriptional co-activators of the Six family of homeoproteins. Subsequently, the highly conserved C-terminal domains of the Eya proteins were discovered to act as a Mg²⁺-dependent Tyr phosphatases, making Eyas the first transcriptional activators to harbor intrinsic phosphatase activity. Only two direct targets of the Eya Tyr phosphatase have been identified: H2AX, whose dephosphorylation directs cells to the DNA repair instead of the apoptotic pathway upon DNA damage, and ERβ, whose dephosphorylation inhibits its anti-tumor transcriptional activity. The Eya Tyr phosphatase mediates breast cancer cell transformation, migration, invasion, as well as metastasis, through targets not yet identified. Intriguingly, the N-terminal domain of Eya contains a separate Ser/Thr phosphatase activity implicated in innate immunity and in regulating c-Myc stability. Thus, Eya proteins are highly complex, containing two separable phosphatase domains and a transcriptional activation domain, thereby influencing tumor progression through multiple mechanisms.

Noncoding RNA in drug resistant sarcoma

Sarcomas are a group of malignant tumors that arise from mesenchymal origin. Despite significant development of multidisciplinary treatments for sarcoma, survival rates have reached a plateau. Chemotherapy has been extensively used for sarcoma treatment; however, the development of drug resistance is a major obstacle limiting the success of many anticancer agents. Sarcoma biology has traditionally focused on genomic and epigenomic deregulation of protein-coding genes to identify the therapeutic potential for reversing drug resistance. New and more creative approaches have found the involvement of noncoding RNAs, including microRNAs and long noncoding RNAs in drug resistant sarcoma. In this review, we discuss the current knowledge of noncoding RNAs characteristics and the regulated genes involved in drug resistant sarcoma, and focus on their therapeutic potential in the future.

Biomarkers of Osteosarcoma, Chondrosarcoma, and Ewing Sarcoma

Osteosarcoma is the most frequent malignant bone neoplasm, followed by chondrosarcoma and Ewing sarcoma. The diagnosis of bone neoplasms is generally made through histological evaluation of a biopsy. Clinical and radiological features are also important in aiding diagnosis and to complete the staging of bone cancer. In addition to these, there are several non-specific serological or specific molecular markers for bone neoplasms. In bone tumors, molecular markers increase the accuracy of the diagnosis and assist in subtyping bone tumors. Here, we review these markers and discuss their role in the diagnosis and prognosis of the three most frequent malignant bone neoplasms, namely osteosarcoma, chondrosarcoma, and Ewing sarcoma.

Methylation of the phosphatase-transcription activator EYA1 by protein arginine methyltransferase 1: mechanistic, functional, and structural studies

The eyes absent (EYA) family proteins are conserved transcriptional coactivators with intrinsic protein phosphatase activity. They play an essential role in the development of various organs in metazoans. These functions are associated with a unique combination of phosphatase and transactivation activities. However, it remains poorly understood how these activities and the consequent biologic functions of EYA are regulated. Here, we demonstrate that 2 conserved arginine residues, R304 and R306, of EYA1 are essential for its in vitro phosphatase activity and in vivo function during Drosophila eye development. EYA1 physically interacts with protein arginine methyltransferase 1, which methylates EYA1 at these residues both in vitro and in cultured mammalian and insect cells. Moreover, we show that wild-type, but not methylation-defective, EYA1 associates with γ-H2A.X in response to ionizing radiation. Taken together, our results identify the conserved arginine residues of EYA1 that play an important role for its activity, thus implicating arginine methylation as a novel regulatory mechanism of EYA function.-Li, X., Eberhardt, A., Hansen, J. N., Bohmann, D., Li, H., Schor, N. F. Methylation of the phosphatase-transcription activator EYA1 by protein arginine methyltransferase 1: mechanistic, functional, and structural studies.

Hsa-let-7c-5p augments enterovirus 71 replication through viral subversion of cell signaling in rhabdomyosarcoma cells

Background

Human enterovirus 71 (EV71) causes severe hand, foot and mouse disease, accompanied by neurological complications. During the interaction between EV71 and the host, the virus subverts host cell machinery for its own replication. However, the roles of microRNAs (miRNAs) in this process remain obscure.

Results

In this study, we found that the miRNA hsa-let-7c-5p was significantly upregulated in EV71-infected rhabdomyosarcoma cells. The overexpression of hsa-let-7c-5p promoted replication of the virus, and the hsa-let-7c-5p inhibitor suppressed viral replication. Furthermore, hsa-let-7c-5p targeted mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) and inhibited its expression. Interestingly, downregulation of MAP4K4 expression led to an increase in EV71 replication. In addition, MAP4K4 knockdown or transfection with the hsa-let-7c-5p mimic led to activation of the c-Jun NH2-terminal kinase (JNK) signaling pathway, whereas the hsa-let-7c-5p inhibitor inhibited activation of this pathway. Moreover, EV71 infection promoted JNK pathway activation to facilitate viral replication.

Conclusions

Our data suggested that hsa-let-7c-5p facilitated EV71 replication by inhibiting MAP4K4 expression, which might be related to subversion of the JNK pathway by the virus. These results may shed light on a novel mechanism underlying the defense of EV71 against cellular responses. In addition, these findings may facilitate the development of new antiviral strategies for use in future therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13578-017-0135-9) contains supplementary material, which is available to authorized users.

MicroRNA-708-5p acts as a therapeutic agent against metastatic lung cancer

MicroRNAs (miRNAs) have recently been recognized as targets for anti-metastatic therapy against cancer malignancy. Development of effective miRNA mediated therapies remains a challenge to both basic research and clinical practice. Here we presented the evidence for a miR-708-5p mediated replacement therapy against metastatic lung cancer. Expression of miR-708-5p was substantially reduced in metastatic lung cancer samples and cancer cell lines when compared to non-metastatic counterparts. Expression of the miRNA suppressed cell survival and metastasis in vitro through its direct target p21, and inhibited the PI3K/AKT pathway and stem cell-like characteristics of lung cancer cells. Systemic administration of this miRNA in a mouse model of NSCLC using polyethylenimine (PEI)-mediated delivery of unmodified miRNA mimics induced tumor specific apoptosis. It also effectively protected the tested animals from developing metastatic malignancy without causing any observed toxicity. The findings strongly support miR-708-5p as a novel and effective therapeutic agent against metastatic malignancy of non-small cell lung cancer.

Induction of the mesenchymal to epithelial transition by demethylation-activated microRNA-125b is involved in the anti-migration/invasion effects of arsenic trioxide on human chondrosarcoma

Background

In addition to treating acute promyelocytic leukemia, arsenic trioxide (ATO) suppresses other solid tumors, including chondrosarcoma. However, the effects of ATO on metastasis in chondrosarcoma cells, and the underlying molecular mechanisms remain unclear.

Methods

The effects of ATO on the migratory and invasive capacities of chondrosarcoma cells were investigated by Wound healing, Transwell and EMT assays. The expression of miR-125b in human chondrosarcoma tissues and cell lines was detected by real-time PCR analysis. Bisulfite sequencing analysis (BSP) was used to detect the effects of ATO on the expression of miR-125b. The gain-of-function and loss-of-function experiments were performed on chondrosarcoma cell lines to investigate the effects of miR-125b on chondrosarcoma invasion, and to determine whether signal transducer and activator of transcription 3(Stat3) mediates these effects. Dual-luciferase reporter assay was used to identify whether Stat3 is a direct target of miR-125b.

Results

MiR-125b was significantly downregulated in human metastatic chondrosarcoma tissues and cell lines but not in non-metastatic chondrosarcoma tissues. ATO up-regulates the expression of miR-125b by the demethylation of DNA. ATO induces MET and attenuates the invasive capacities of chondrosarcoma cells through miR-125b. Stat3 was verified as a direct target of miR-125b, which is involved in ATO regulating EMT-associated traits.

Conclusions

These findings, for the first time, provides evidence that the miR-125b-mediated inhibition of Stat3 is involved in the ATO-induced attenuation of metastasis in chondrosarcoma cells.

Twenty Years on: What Do We Really Know about Ewing Sarcoma and What Is the Path Forward?

Ewing sarcoma (ES) is a highly aggressive bone and soft-tissue tumor with peak incidence among adolescents and young adults. Despite advances in local control and systemic chemotherapy, metastatic relapse after an initial clinical remission remains a significant clinical problem. In addition, metastasis at the time of presentation or at relapse continues to be the leading cause of death for patients diagnosed with ES. Since the discovery of the pathognomonic EWS-FLI1 fusion gene more than 20 years ago, much about the molecular and cellular biology of ES pathogenesis has been learned. In addition, more recent exploitation of advances in stem cell and developmental biology has provided key insights into the cellular origins of ES and the role of epigenetic deregulation in tumor initiation and maintenance. Nevertheless, the mechanisms that drive tumor relapse and metastasis remain largely unknown. These gaps in our knowledge continue to hamper the development of novel therapeutic strategies that may improve outcomes for patients with relapsed and metastatic disease. In this article we review the current status of ES biology research, highlighting areas of investigation that we consider to have the greatest potential to yield findings that will translate into clinically significant advances.

Ewing sarcoma: a chronicle of molecular pathogenesis

Sarcomas have traditionally been classified according to their chromosomal alterations regardless of whether they accompany simple or complex genetic changes. Ewing sarcoma, a classic small round cell bone tumor, is a well-known mesenchymal malignancy that results from simple sarcoma-specific genetic alterations. The genetic alterations are translocations between genes of the TET/FET family (TLS/FUS, EWSR1, and TAF15) and genes of the E26 transformation-specific (ETS) family. In this review, we intend to summarize a chronicle of molecular findings of Ewing sarcoma including recent advances and explain resultant molecular pathogenesis.

EYA1 expression and subcellular localization in neuroblastoma and its association with prognostic markers

Neuroblastoma, the most frequently occurring extracranial solid tumor of childhood, arises from neural crest-derived cells that are arrested at an early stage of differentiation in the developing sympathetic nervous system. There is an urgent need to identify clinically relevant biomarkers for better prognosis and treatment of this aggressive malignancy. Eyes Absent 1 (EYA1) is an essential transcriptional coactivator for neuronal developmental programs during organogenesis. Whether or not EYA1 is implicated in neuroblastoma and subcellular localization of EYA1 is relevant to clinical behaviour of neuroblastoma is not known. We studied EYA1 expression and subcellular localization by immunohistochemistry in tissue microarrays containing tumor specimens from 98 patients, 66 of which were characterized by known clinical prognostic markers of neuroblastoma. Immunostaining results were evaluated and statistically correlated with the degree of histologic differentiation and with neuroblastoma risk stratification group characteristics, including stage of disease, patient age, tumor histology and mitosis-karyorrhexis index (MKI), respectively. We found that EYA1 levels were significantly higher in neuroblastomas than in ganglioneuromas and ganglioneuroblastomas. EYA1 was more highly expressed in stage 1,2,3 or 4S tumors as compared to stage 4 tumors (P<0.01). Tumors with high levels of nuclear EYA1 were more frequently associated with high nuclear MYCN levels. These results suggest that modulation of expression and intracellular localization of EYA1 in neural crest cells may provide a novel direction for therapeutic strategies.

microRNA and Bone Cancer

MicroRNA molecules have a variety of roles in cellular development and proliferation processes, including normal osteogenesis. These effects are exerted through post-translational inhibition of target genes. Altered miRNA expression has been demonstrated in several cancers, both in the tumor tissue and in the peripheral circulation. This may influence carcinogenesis if the specific miRNA targets are encoded by tumor suppressor genes or oncogenes. To date, most research investigating the role of microRNAs and primary bone tumors has focused on osteosarcoma and Ewing sarcoma. Several microRNAs including the miR-34 family have been implicated in osteosarcoma tumorigenesis via effects on the Notch signaling pathway. Progression, invasion, and metastasis of osteosarcoma tumor cells is also influenced by microRNA expression. In addition, microRNA expression may affect the response to chemotherapy in osteosarcoma and thus hold potential for future use as either a prognostic indicator or a therapeutic target. The EWS-FLI1 fusion protein produced in Ewing sarcoma has been shown to induce changes in miRNA expression. MicroRNA expression profiling may have some potential for prediction of disease progression and survival in Ewing sarcoma. There is limited evidence to support a role for microRNAs in other primary bone tumors, either malignant or benign; however, early work is suggestive of involvement in chondrosarcoma, multiple osteochondromatosis, and giant cell tumors of bone.

Mechanisms of doxorubicin resistance in hepatocellular carcinoma

Hepatocellular carcinoma, one of the most common solid tumors worldwide, is poorly responsive to available chemotherapeutic approaches. While systemic chemotherapy is of limited benefit, intra-arterial delivery of doxorubicin to the tumor frequently produces tumor shrinkage. Its utility is limited, in part, by the frequent emergence of doxorubicin resistance. The mechanisms of this resistance include increased expression of multidrug resistance efflux pumps, alterations of the drug target, topoisomerase, and modulation of programmed cell death pathways. Many of these effects result from changes in miRNA expression and are particularly prominent in tumor cells with a stem cell phenotype. This review will summarize the current knowledge on the mechanisms of doxorubicin resistance of hepatocellular carcinoma and the potential for approaches toward therapeutic chemosensitization.