Downregulation of microRNAs miR-1, -206 and -29 stabilizes PAX3 and CCND2 expression in rhabdomyosarcoma

miRNA-1 regulation is necessary for mechanical overload-induced muscle hypertrophy in male mice

MicroRNAs (miRNAs) are small, noncoding RNAs that play a critical role in regulating gene expression post-transcriptionally. They are involved in various developmental and physiological processes, and their dysregulation is linked to various diseases. Skeletal muscle-specific miRNAs, including miR-1, play a crucial role in the development and maintenance of skeletal muscle. It has been demonstrated that the expression of miR-1 decreases by approximately 50% in response to hypertrophic stimuli, suggesting its potential involvement in muscle hypertrophy. In our study, we hypothesize that reduction of miR-1 levels is necessary for skeletal muscle growth due to its interaction to essential pro-growth genes. Promoting a smaller reduction of miR-1 levels, we observed a blunted hypertrophic response in mice undergoing a murine model of muscle hypertrophy. In addition, our results suggest that miR-1 inhibits the expression of Itm2a, a membrane-related protein, as potential miR-1-related candidate for skeletal muscle hypertrophy. While the exact mechanism in muscle hypertrophy has not been identified, our results suggest that miR-1-regulated membrane proteins are important for skeletal muscle hypertrophy.

Circ_0002331 Interacts with ELAVL1 to Improve ox-LDL-Induced Vascular Endothelial Cell Dysfunction via Regulating CCND2 mRNA Stability

Circular RNAs (circRNAs) have been discovered to serve as vital regulators in atherosclerosis (AS). However, the role and mechanism of circ_0002331 in AS process are still unclear. Human umbilical vein endothelial cells (HUVECs) were treated with ox-LDL to establish an in vitro model for AS. The expression levels of circ_0002331, Cyclin D2 (CCND2) and ELAVL1 were analyzed by quantitative real-time PCR. Cell proliferation, apoptosis, migration, invasion and angiogenesis were assessed by EdU assay, flow cytometry, transwell assay and tube formation assay. The protein levels of CCND2, ELAVL1, and autophagy-related markers were detected using western blot analysis. IL-8 level was analyzed by ELISA. The relationship between ELAVL1 and circ_0002331 or CCND2 was analyzed by RIP assay and RNA pull-down assay. Moreover, FISH assay was used to analyze the co-localization of ELAVL1 and CCND2 in HUVECs. Our data showed that circ_0002331 was obviously downregulated in AS patients and ox-LDL-induced HUVECs. Overexpression of circ_0002331 could promote proliferation, migration, invasion and angiogenesis, while inhibit apoptosis, autophagy and inflammation in ox-LDL-induced HUVECs. Furthermore, CCND2 was positively regulated by circ_0002331, and circ_0002331 could bind with ELAVL1 to promote CCND2 mRNA stability. Besides, CCND2 overexpression suppressed ox-LDL-induced HUVECs dysfunction, and its knockdown also reversed the regulation of circ_0002331 on ox-LDL-induced HUVECs dysfunction. In conclusion, circ_0002331 might be a potential target for AS treatment, which could improve ox-LDL-induced dysfunction of HUVECs via regulating CCND2 by binding with ELAVL1.

MicroRNAs and angiosarcoma: are there promising reports?

In recent years, microRNAs (miRNAs) have garnered increasing attention for their potential implications in cancer pathogenesis, functioning either as oncogenes or tumor suppressors. Notably, angiosarcoma, along with various other cardiovascular tumors such as lipomas, rhabdomyomas, hemangiomas, and myxomas, has shown variations in the expression of specific miRNA subtypes. A substantial body of evidence underscores the pivotal involvement of miRNAs in the genesis of angiosarcoma and certain cardiovascular tumors. This review aims to delve into the current literature on miRNAs and their prospective applications in cardiovascular malignancies, with a specific focus on angiosarcoma. It comprehensively covers diagnostic methods, prognostic evaluations, and potential treatments while providing a recapitulation of angiosarcoma's risk factors and molecular pathogenesis, with an emphasis on the role of miRNAs. These insights can serve as the groundwork for designing randomized control trials, ultimately facilitating the translation of these findings into clinical applications. Moving forward, it is imperative for studies to thoroughly scrutinize the advantages and disadvantages of miRNAs compared to current diagnostic and prognostic approaches in angiosarcoma and other cardiovascular tumors. Closing these knowledge gaps will be crucial for harnessing the full potential of miRNAs in the realm of angiosarcoma and cardiovascular tumor research.

The PAX Genes: Roles in Development, Cancer, and Other Diseases

Since their 1986 discovery in Drosophila, Paired box (PAX) genes have been shown to play major roles in the early development of the eye, muscle, skeleton, kidney, and other organs. Consistent with their roles as master regulators of tissue formation, the PAX family members are evolutionarily conserved, regulate large transcriptional networks, and in turn can be regulated by a variety of mechanisms. Losses or mutations in these genes can result in developmental disorders or cancers. The precise mechanisms by which PAX genes control disease pathogenesis are well understood in some cases, but much remains to be explored. A deeper understanding of the biology of these genes, therefore, has the potential to aid in the improvement of disease diagnosis and the development of new treatments.

miR-460b-5p promotes proliferation and differentiation of chicken myoblasts and targets RBM19 gene

The meat production of broilers is crucial to economic benefits of broiler industries, while the slaughter performance of broilers is directly determined by skeletal muscle development. Hence, the broiler breeding for growth traits shows a great importance. As a kind of small noncoding RNA, microRNA (miRNA) can regulate the expression of multiple genes and perform a wide range of regulation in organisms. Currently, more and more studies have confirmed that miRNAs are closely associated with skeletal muscle development of chickens. Based on our previous miR-seq analysis (accession number: PRJNA668199), miR-460b-5p was screened as one of the key miRNAs probably involved in the growth regulation of chickens. However, the regulatory effect of miR-460b-5p on the development of chicken skeletal muscles is still unclear. Therefore, miR-460b-5p was further used for functional validation at the cellular level in this study. The expression pattern of miR-460b-5p was investigated in proliferation and differentiation stages of chicken primary myoblasts. It was showed that the expression level of miR-460b-5p gradually decreased from the proliferation stage (GM 50%) to the lowest at 24 h of differentiation. As differentiation proceeded, miR-460b-5p expression increased significantly, reaching the highest and stabilizing at 72 h and 96 h of differentiation. Through mRNA quantitative analysis of proliferation marker genes, CCK-8 and Edu assays, miR-460b-5p was found to significantly facilitate the transition of myoblasts from G1 to S phase and promote chicken myoblast proliferation. mRNA and protein quantitative analysis of differentiation marker genes, as well as the indirect immunofluorescence results of myotubes, revealed that miR-460b-5p significantly stimulated myotube development and promote chicken myoblast differentiation. In addition, the target relationship was validated for miR-460b-5p according to the dual-luciferase reporter assay and mRNA quantitative analysis, which indicates that miR-460b-5p was able to regulate RBM19 expression by specifically binding to the 3' UTR of RBM19. In summary, miR-460b-5p has positive regulatory effects on the proliferation and differentiation of chicken myoblasts, and RBM19 is a target gene of miR-460b-5p.

Fusion-negative rhabdomyosarcoma 3D organoids to predict effective drug combinations: A proof-of-concept on cell death inducers

Rhabdomyosarcoma (RMS) is the main form of pediatric soft-tissue sarcoma. Its cure rate has not notably improved in the last 20 years following relapse, and the lack of reliable preclinical models has hampered the design of new therapies. This is particularly true for highly heterogeneous fusion-negative RMS (FNRMS). Although methods have been proposed to establish FNRMS organoids, their efficiency remains limited to date, both in terms of derivation rate and ability to accurately mimic the original tumor. Here, we present the development of a next-generation 3D organoid model derived from relapsed adult and pediatric FNRMS. This model preserves the molecular features of the patients' tumors and is expandable for several months in 3D, reinforcing its interest to drug combination screening with longitudinal efficacy monitoring. As a proof-of-concept, we demonstrate its preclinical relevance by reevaluating the therapeutic opportunities of targeting apoptosis in FNRMS from a streamlined approach based on transcriptomic data exploitation.

A dysfunctional miR-1-TRPS1-MYOG axis drives ERMS by suppressing terminal myogenic differentiation

Rhabdomyosarcoma is the most common pediatric soft tissue tumor, comprising two major subtypes: the PAX3/7-FOXO1 fusion-negative embryonal and the PAX3/7-FOXO1 fusion-positive alveolar subtype. Here, we demonstrate that the expression levels of the transcriptional repressor TRPS1 are specifically enhanced in the embryonal subtype, resulting in impaired terminal myogenic differentiation and tumor growth. During normal myogenesis, expression levels of TRPS1 have to decrease to allow myogenic progression, as demonstrated by overexpression of TRPS1 in myoblasts impairing myotube formation. Consequentially, myogenic differentiation in embryonal rhabdomyosarcoma in vitro as well as in vivo can be achieved by reducing TRPS1 levels. Furthermore, we show that TRPS1 levels in RD cells, the bona fide model cell line for embryonal rhabdomyosarcoma, are regulated by miR-1 and that TRPS1 and MYOD1 share common genomic binding sites. The myogenin (MYOG) promoter is one of the critical targets of TRPS1 and MYOD1; we demonstrate that TRPS1 restricts MYOG expression and thereby inhibits terminal myogenic differentiation. Therefore, reduction of TRPS1 levels in embryonal rhabdomyosarcoma might be a therapeutic approach to drive embryonal rhabdomyosarcoma cells into myogenic differentiation, thereby generating postmitotic myotubes.

Hierarchically Injectable Hydrogel Sequentially Delivers AntagomiR-467a-3p-Loaded and AntagomiR-874-5p-Loaded Satellite-Cell-Targeting Bioengineered Extracellular Vesicles Attenuating Sarcopenia

Sarcopenia is a geriatric disease characterized by reduced muscle function and mass. The capacity to self-renew and myogenesis of satellite cells (SCs) declines with age, resulting in age-related sarcopenia. MicroRNAs (miRNAs) can regulate the proliferation and myogenesis of SCs. In this study, it is identified that miR-467a-3p and miR-874-5p could respectively mediate the stemness and myogenesis of SCs by performing bioinformatics analysis. AntagomiR-467a-3p (ant-467a) and antagomiR-874-5p (ant-874) improve the stemness and myogenesis of SCs, respectively. SC-targeting extracellular vesicles (EVs) are constructed by overexpressing TSG101 on the surface of EVs isolated from bone marrow mesenchymal stem cells. Ant-467a loaded EVs (EVs-467a) and ant-874 loaded EVs (EVs-874) are prepared by transferring ant-467a and ant-874 into SC-targeting EVs. EVs-467a and EVs-874 are more effective than ant-467a and ant-874 in promoting the stemness and myogenesis of SCs. Sequentially intermuscular injection of EVs-467a and EVs-874 significantly improve sarcopenia in ovariectomy mice. The effects of multiple injections of EVs-467a and EVs-874 in the treatment of sarcopenia could be achieved by using a hierarchically injectable hydrogel to sustainedly release EVs-467a and EVs-874 in vivo. The findings provide an EV-based SC-targeting antagomiRNAs controlled release strategy as a novel therapy against sarcopenia.

Small Non-Coding RNAs in Soft-Tissue Sarcomas: State of the Art and Future Directions

Soft-tissue sarcomas (STS) are a rare and heterogeneous group of tumors that arise from connective tissue and can occur anywhere in the body. Among the plethora of over 50 different STS types, liposarcoma (LPS) is one of the most common. The subtypes of STS are characterized by distinct differences in tumor biology that drive responses to pharmacologic therapy and disparate oncologic outcomes. Small non-coding RNAs (sncRNA) are a heterogeneous class of regulatory RNAs involved in the regulation of gene expression by targeting mRNAs. Among the several types of sncRNAs, miRNAs and tRNA-derived ncRNAs are the most studied in the context of tumor biology, and we are learning more about the role of these molecules as important regulators of STS tumorigenesis and differentiation. However, challenges remain in translating these findings and no biomarkers or therapeutic approaches targeting sncRNAs have been developed for clinical use. In this review, we summarize the current landscape of sncRNAs in the context of STS with an emphasis on LPS, including the role of sncRNAs in the tumorigenesis and differentiation of these rare malignancies and their potential as novel biomarkers and therapeutic targets. Finally, we provide an appraisal of published studies and outline future directions to study sncRNAs in STS, including tRNA-derived ncRNAs.

MicroRNAs in the Pathogenesis, Prognostication and Prediction of Treatment Resistance in Soft Tissue Sarcomas

Soft tissue sarcomas are highly aggressive malignant neoplasms of mesenchymal origin, accounting for less than 1% of adult cancers, but comprising over 20% of paediatric solid tumours. In locally advanced, unresectable, or metastatic disease, outcomes from even the first line of systemic treatment are invariably poor. MicroRNAs (miRNAs), which are short non-coding RNA molecules, target and modulate multiple dysregulated target genes and/or signalling pathways within cancer cells. Accordingly, miRNAs demonstrate great promise for their utility in diagnosing, prognosticating and improving treatment for soft tissue sarcomas. This review aims to provide an updated discussion on the known roles of specific miRNAs in the pathogenesis of sarcomas, and their potential use in prognosticating outcomes and prediction of therapeutic resistance.

Non-coding RNA in rhabdomyosarcoma progression and metastasis

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma of skeletal muscle differentiation, with a predominant occurrence in children and adolescents. One of the major challenges facing treatment success is the presence of metastatic disease at the time of diagnosis, commonly associated with the more aggressive fusion-positive subtype. Non-coding RNA (ncRNA) can regulate gene transcription and translation, and their dysregulation has been associated with cancer development and progression. MicroRNA (miRNA) are short non-coding nucleic acid sequences involved in the regulation of gene expression that act by targeting messenger RNA (mRNA), and their aberrant expression has been associated with both RMS initiation and progression. Other ncRNA including long non-coding RNA (lncRNA), circular RNA (circRNA) and ribosomal RNA (rRNA) have also been associated with RMS revealing important mechanistic roles in RMS biology, but these studies are still limited and require further investigation. In this review, we discuss the established roles of ncRNA in RMS differentiation, growth and progression, highlighting their potential use in RMS prognosis, as therapeutic agents or as targets of treatment.

Association between microRNA 671 polymorphisms and the susceptibility to soft tissue sarcomas in a Chinese population

This study evaluated the association between the microRNA (miRNA) gene polymorphisms and the susceptibility to soft tissue sarcomas (STSs). In this case–control study, DNA was extracted from leukocytes in peripheral blood, which was collected from 169 STSs patients and 170 healthy controls. Three SNPs for miR-210, five SNPs for miR-206, two SNPs for miR-485, two SNPs for miR-34b, two SNPs for miR-671, and three SNPs for miR-381 were investigated and genotyped using a Sequenom Mass ARRAY matrix-assisted laser desorption/ionization-time of flight mass spectrometry platform. Unconditional logistic regression analysis was used to analyze the association between miRNA gene polymorphisms and the susceptibility to STSs. The results showed that miR-671 rs1870238 GC + CC (OR = 1.963, 95% CI = 1.258–3.064, P = 0.003) and miR-671 rs2446065 CG + GG (OR =1.838, 95% CI = 1.178–2.868, P = 0.007) may be genetic risk factors for STSs after adjustment for age and smoking. Therefore, this study suggests that individuals carrying the GC + CC genotype for miR-671 rs1870238 or the CG + GG genotype for miR-671 rs2446065 are susceptible to STSs.

Characterization of the circRNA–miRNA–mRNA Network to Reveal the Potential Functional ceRNAs Associated With Dynamic Changes in the Meat Quality of the Longissimus Thoracis Muscle in Tibetan Sheep at Different Growth Stages

Circular RNAs (circRNAs) have a regulatory role in animal skeletal muscle development. In this study, RNA sequencing was performed to reveal the temporal regularity of circRNA expression and the effect of the circRNA–miRNA–mRNA ceRNA regulatory network on the meat quality of longissimus thoracis (LT) muscle in Tibetan sheep at different growth stages (4 months old, 4 m; 1.5 years old, 1.5 y; 3.5 years old, 3.5 y; 6 years old, 6 y). There were differences in the carcass performance and meat quality of Tibetan sheep at different ages. Especially, the meat tenderness significantly decreased (p < 0.05) with the increase of age. GO functional enrichment indicated that the source genes of the DE circRNAs were mainly involved in the protein binding, and myofibril and organelle assembly. Moreover, there was a significant KEGG enrichment in the adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway, as well as the calcium signaling pathway, regulating the pluripotency of the stem cells. The circRNA–miRNA–mRNA ceRNA interaction network analysis indicated that circRNAs such as circ_000631, circ_000281, and circ_003400 combined with miR-29-3p and miR-185-5p regulate the expression of LEP, SCD, and FASN related to the transformation of muscle fiber types in the AMPK signaling pathway. The oxidized muscle fibers were transformed into the glycolytic muscle fibers with the increase of age, the content of intramuscular fat (IMF) was lowered, and the diameter of the muscle fiber was larger in the glycolytic muscle fibers, ultimately increasing the meat tenderness. The study revealed the role of the circRNAs in the transformation of skeletal muscle fiber types in Tibetan sheep and its influence on meat quality. It improves our understanding of the role of circRNAs in Tibetan sheep muscle development.

Therapeutic Implications of miRNAs for Muscle-Wasting Conditions

MicroRNAs (miRNAs) are small, non-coding RNA molecules that are mainly involved in translational repression by binding to specific messenger RNAs. Recently, miRNAs have emerged as biomarkers, relevant for a multitude of pathophysiological conditions, and cells can selectively sort miRNAs into extracellular vesicles for paracrine and endocrine effects. In the overall context of muscle-wasting conditions, a multitude of miRNAs has been implied as being responsible for the typical dysregulation of anabolic and catabolic pathways. In general, chronic muscle disorders are associated with the main characteristic of a substantial loss in muscle mass. Muscular dystrophies (MDs) are a group of genetic diseases that cause muscle weakness and degeneration. Typically, MDs are caused by mutations in those genes responsible for upholding the integrity of muscle structure and function. Recently, the dysregulation of miRNA levels in such pathological conditions has been reported. This revelation is imperative for both MDs and other muscle-wasting conditions, such as sarcopenia and cancer cachexia. The expression levels of miRNAs have immense potential for use as potential diagnostic, prognostic and therapeutic biomarkers. Understanding the role of miRNAs in muscle-wasting conditions may lead to the development of novel strategies for the improvement of patient management.

Soft Tissue Sarcoma: An Insight on Biomarkers at Molecular, Metabolic and Cellular Level

Simple Summary

Soft tissue sarcoma is a rare mesenchymal malignancy. Despite the advancements in the fields of radiology, pathology and surgery, these tumors often recur locally and/or with metastatic disease. STS is considered to be a diagnostic challenge due to the large variety of histological subtypes with clinical and histopathological characteristics which are not always distinct. One of the important clinical problems is a lack of useful biomarkers. Therefore, the discovery of biomarkers that can be used to detect tumors or predict tumor response to chemotherapy or radiotherapy could help clinicians provide more effective clinical management.

Abstract

Soft tissue sarcomas (STSs) are a heterogeneous group of rare tumors. Although constituting only 1% of all human malignancies, STSs represent the second most common type of solid tumors in children and adolescents and comprise an important group of secondary malignancies. Over 100 histologic subtypes have been characterized to date (occurring predominantly in the trunk, extremity, and retroperitoneum), and many more are being discovered due to molecular profiling. STS mortality remains high, despite adjuvant chemotherapy. New prognostic stratification markers are needed to help identify patients at risk of recurrence and possibly apply more intensive or novel treatments. Recent scientific advancements have enabled a more precise molecular characterization of sarcoma subtypes and revealed novel therapeutic targets and prognostic/predictive biomarkers. This review aims at providing a comprehensive overview of the most relevant cellular, molecular and metabolic biomarkers for STS, and highlight advances in STS-related biomarker research.

Comprehensive analysis of differentially expressed circRNAs and ceRNA regulatory network in porcine skeletal muscle

BACKGROUND

Circular RNA (circRNA), a novel class of non-coding RNA, has a closed-loop structure with important functions in skeletal muscle growth. The purpose of this study was to investigate the role of differentially expressed circRNAs (DEcircRNAs), as well as the DEcircRNA-miRNA-mRNA regulatory network, at different stages of porcine skeletal muscle development. Here, we present a panoramic view of circRNA expression in porcine skeletal muscle from Large White and Mashen pigs at 1, 90, and 180 days of age.

RESULTS

We identified a total of 5819 circRNAs. DEcircRNA analysis at different stages showed 327 DEcircRNAs present in both breeds. DEcircRNA host genes were concentrated predominately in TGF-β, MAPK, FoxO, and other signaling pathways related to skeletal muscle growth and fat deposition. Further prediction showed that 128 DEcircRNAs could bind to 253 miRNAs, while miRNAs could target 945 mRNAs. The constructed ceRNA network plays a vital role in skeletal muscle growth and development, and fat deposition. Circ_0015885/miR-23b/SESN3 in the ceRNA network attracted our attention. miR-23b and SESN3 were found to participate in skeletal muscle growth regulation, also playing an important role in fat deposition. Using convergent and divergent primer amplification, RNase R digestion, and qRT-PCR, circ_0015885, an exonic circRNA derived from Homer Scaffold Protein 1 (HOMER1), was confirmed to be differentially expressed during skeletal muscle growth. In summary, circ_0015885 may further regulate SESN3 expression by interacting with miR-23b to function in skeletal muscle.

CONCLUSIONS

This study not only enriched the circRNA library in pigs, but also laid a solid foundation for the screening of key circRNAs during skeletal muscle growth and intramural fat deposition. In addition, circ_0015885/miR-23b/SESN3, a new network regulating skeletal muscle growth and fat deposition, was identified as important for increasing the growth rate of pigs and improving meat quality.

miR-299-3p suppresses cell progression and induces apoptosis by downregulating PAX3 in gastric cancer

Gastric cancer (GC) is ranked the fourth leading cause of cancer-related death, with an over 75% mortality rate worldwide. In recent years, miR-299-3p has been identified as a biomarker in multiple cancers, such as acute promyelocytic leukemia, thyroid cancer, and lung cancer. However, the regulatory mechanism of miR-299-3p in GC cell progression is still largely unclear. Cell viability and apoptosis tests were performed by CCK8 and flow cytometry assay, respectively. Transwell assay was recruited to examine cell invasion ability. The interaction between miR-299-3p and PAX3 was determined by the luciferase reporter system. PAX3 protein level was evaluated by western blot assay. The expression of miR-299-3p was downregulated in GC tissues and cell lines (MKN-45, AGS, and MGC-803) compared with the normal tissues and cells. Besides, overexpression of miR-299-3p significantly suppressed proliferation and invasion and promoted apoptosis in GC. Next, we clarified that PAX3 expression was regulated by miR-299-3p using a luciferase reporter system, qRT-PCR, and western blot assay. Additionally, downregulation of PAX3 repressed GC cell progression. The rescue experiments indicated that restoration of PAX3 inversed miR-299-3p-mediated inhibition on cell proliferation and invasion. miR-299-3p suppresses cell proliferation and invasion as well as induces apoptosis by regulating PAX3 expression in GC, representing desirable biomarkers for GC diagnosis and therapy.

Circulating miR-26a as Potential Prognostic Biomarkers in Pediatric Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) arises from myogenic precursors that fail to complete muscle differentiation and represents the most frequent soft tissue sarcoma in children. Two major histological subtypes are recognized: alveolar RMS, characterized by a more aggressive behavior and a greater proneness to metastasis, and embryonal RMS which accounts for the 80% of cases and carries a better prognosis. Despite the survival of patients with localized tumors has progressively improved, RMS remains a challenging disease especially for metastatic patients and in case of progressive or recurrent disease after front-line therapy. MicroRNAs, a class of small non-coding RNA, have emerged as crucial players in cancer development and progression, and their detection in plasma (circulating miRNAs) represents a promising minimally invasive approach that deserve to be exploited in clinical practice. We evaluated the utility of circulating miRNAs as diagnostic and prognostic biomarkers in children with RMS profiling miRNAs from plasma of a small cohort of RMS patients and healthy donors (HD) using a qPCR Cancer Panel. An assessment of hemolysis status of plasma using miR-451/miR-23a ratio was performed as pre-analytical analysis. Statistical analysis revealed that miRNAs expression pattern clearly distinguished RMS patients from HD (p < 0.05). Interestingly, plasma levels of muscle-specific miR-206 were found to be significantly increased in RMS patients compared to HD, whereas levels of three potential tumor-suppressor miRNAs, miR-26a and miR-30b/30c, were found lower. Reduced levels of circulating miR-26a and miR-30b/c were further measured in an independent larger cohort of patients (validation set) by digital droplet PCR. In particular, we evidenced that miR-26a absolute plasma levels were associated with fusion status and adverse outcome (p < 0.05). Taken together, these findings demonstrate the potential of circulating miRNA as diagnostic and prognostic biomarker in children affected by this malignancy and enforced the key role of miR-26a in pediatric rhabdomyosarcoma.

MicroRNAs in Skeletal Muscle and Hints on Their Potential Role in Muscle Wasting During Cancer Cachexia

Cancer-associated cachexia is a heterogeneous, multifactorial syndrome characterized by systemic inflammation, unintentional weight loss, and profound alteration in body composition. The main feature of cancer cachexia is represented by the loss of skeletal muscle tissue, which may or may not be accompanied by significant adipose tissue wasting. Such phenotypic alteration occurs as the result of concomitant increased myofibril breakdown and reduced muscle protein synthesis, actively contributing to fatigue, worsening of quality of life, and refractoriness to chemotherapy. According to the classical view, this condition is primarily triggered by interactions between specific tumor-induced pro-inflammatory cytokines and their cognate receptors expressed on the myocyte membrane. This causes a shift in gene expression of muscle cells, eventually leading to a pronounced catabolic condition and cell death. More recent studies, however, have shown the involvement of regulatory non-coding RNAs in the outbreak of cancer cachexia. In particular, the role exerted by microRNAs is being widely addressed, and several mechanistic studies are in progress. In this review, we discuss the most recent findings concerning the role of microRNAs in triggering or exacerbating muscle wasting in cancer cachexia, while mentioning about possible roles played by long non-coding RNAs and ADAR-mediated miRNA modifications.

Integrated Analysis of Three Publicly Available Gene Expression Profiles Identified Genes and Pathways Associated with Clear Cell Renal Cell Carcinoma

BACKGROUND Although advances have been achieved in the therapy of clear cell renal cell carcinoma (ccRCC), the pathogenesis of ccRCC is not yet fully understood. This study aimed to explore the critical genes and pathways associated with ccRCC by meta-analysis. MATERIAL AND METHODS We performed an integrated analysis of 3 publicly available microarray datasets developed from ccRCC tumor samples and normal tissues. A list of overlapped differentially expressed genes (DEGs) with the consistent expression trend in ccRCC tumor samples were identified, for which the protein-protein interaction (PPI) network was constructed, followed by topology structure and module analysis. The microRNA (miRNA) regulatory network and ccRCC associated pathway network were reconstructed. RESULTS A total of 504 genes were found to be consistently and differentially regulated based on 3 microarray datasets. The overrepresented pathways for DEGs included citric acid cycle (TCA cycle) and peroxisome proliferator-activated receptor (PPAR) signaling pathway and cell cycle. The PPI network was clustered into 6 modules that were closely related with the M phase, desmosome assembly, and response to hormone stimulus. The hsa04110: cell cycle and hsa04510: focal adhesion were the significant pathways associated with ccRCC overlapped with enrichment analysis. KDR and ITGB4 were focal-adhesion-associated genes, which were regulated by has-miR-424 and has-miR-204, respectively. CCND2 and CCNA2 were cell-cycle-associated genes, which were regulated by hsa-miR-324-3p, hsa-miR-146a and hsa-miR-145. CONCLUSIONS Cell cycle and focal adhesion were dysregulated in ccRCC, which were associated with the expression of CCND2, ITGB4, KDR, and CCNA2 genes. The deregulation of pathways and associated genes may provide insights to ccRCC research and therapy.

Systemic Actions of Breast Cancer Facilitate Functional Limitations

Breast cancer is a disease of a specific organ, but its effects are felt throughout the body. The systemic effects of breast cancer can lead to functional limitations in patients who suffer from muscle weakness, fatigue, pain, fibromyalgia, or many other dysfunctions, which hasten cancer-associated death. Mechanistic studies have identified quite a few molecular defects in skeletal muscles that are associated with functional limitations in breast cancer. These include circulating cytokines such as TNF-α, IL-1, IL-6, and TGF-β altering the levels or function of myogenic molecules including PAX7, MyoD, and microRNAs through transcriptional regulators such as NF-κB, STAT3, and SMADs. Molecular defects in breast cancer may also include reduced muscle mitochondrial content and increased extracellular matrix deposition leading to energy imbalance and skeletal muscle fibrosis. This review highlights recent evidence that breast cancer-associated molecular defects mechanistically contribute to functional limitations and further provides insights into therapeutic interventions in managing functional limitations, which in turn may help to improve quality of life in breast cancer patients.

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.

MiRNAs as Players in Rhabdomyosarcoma Development

Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma of childhood and adolescence, is a rare but aggressive malignancy that originates from immature mesenchymal cells committed to skeletal muscle differentiation. Although RMS is, generally, responsive to the modern multimodal therapeutic approaches, the prognosis of RMS depends on multiple variables and for some patients the outcome remains dismal. Further comprehension of the molecular and cellular biology of RMS would lead to identification of novel therapeutic targets. MicroRNAs (miRNAs) are small non-coding RNAs proved to function as key regulators of skeletal muscle cell fate determination and to play important roles in RMS pathogenesis. The purpose of this review is to better delineate the role of miRNAs as a biomarkers or functional leaders in RMS development, so to possibly elucidate some of RMS molecular mechanisms and potentially therapeutically target them to improve clinical management of pediatric RMS.

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.

Circular RNA Regulation of Myogenesis

Circular RNA (circRNA) is a novel class of non-coding RNA generated by pre-mRNA back splicing, which is characterized by a closed-loop structure. Although circRNAs were firstly reported decades ago, their regulatory roles have not been discovered until recently. In this review, we discussed the putative biogenesis pathways and regulatory functions of circRNAs. Recent studies showed that circRNAs are abundant in skeletal muscle tissue, and their expression levels are regulated during muscle development and aging. We, thus, characterized the expression profile of circRNAs in skeletal muscle and discussed regulatory functions and mechanism-of-action of specific circRNAs in myogenesis. The future investigation into the roles of circRNAs in both physiological and pathological conditions may provide novel insights in skeletal muscle development and provide new therapeutic strategies for muscular diseases.

miR-1-3p suppresses the epithelial-mesenchymal transition property in renal cell cancer by downregulating Fibronectin 1

Purpose

Renal cell cancer (RCC) is one of the primary causes of malignancy deaths all over the world. The most important cause of RCC-related mortality is metastasis. Epithelial-mesenchymal transition (EMT) plays an important role in metastasis of malignant tumors including RCC. miR-1-3p is confirmed to be decreased in many types of cancer. Nevertheless, the function of miR-1-3p in RCC metastasis and EMT process was still unclear.

Materials and methods

In this study, information from clinical investigation, in vitro study, and in vivo study discovered miR-1-3p expression character and its status in RCC. The character of miR-1-3p in invasive and metastatic properties in vitro and in vivo was also inspected in RCC cells and xenograft tumor model, and expression levels of EMT markers were evaluated in RCC cells and tissues.

Results

miR-1-3p was proved to be decreased in RCC cell lines and tissues compared with normal renal cells and tissues. miR-1-3p expression level in RCC tissues was closely related with capsulation, lymph node metastasis, and vascular invasion. miR-1-3p was found to be able to block the EMT process in A498 and CAKI-1 RCC cells and tumors. Luciferase reporter assay and expression level rescue assays were employed to reveal that miR-1-3p inhibited the invasion and migration property of RCC cells by directly targeting Fibronectin 1. Upregulation of Fibronectin 1 partially reversed the suppressive effect of miR-1-3p on EMT process.

Conclusion

In brief, this study has verified that miR-1-3p blocked the EMT process of RCC cells by reducing Fibronectin 1 expression. miR-1-3p/Fibronectin 1 axis may be considered as a new target for drug development of RCC.

MiR-1 Suppresses Proliferation of Osteosarcoma Cells by Up-regulating p21 via PAX3

BACKGROUND/AIM

miRNA-1(miR-1) is down-regulated in various cancer cells including osteosarcoma cells. This study was conducted to analyze the function of miR-1 in osteosarcoma cells.

MATERIALS AND METHODS

miR-1 expression in osteosarcoma cells was evaluated by qRT-PCR. Cell proliferation was evaluated after transfecting miR-1 by WST8 assay and FACS analysis, both in vitro and in vivo.

RESULTS

Overexpression of miR-1 suppressed cell proliferation and induced cell-cycle arrest in the G₀-G₁ phase by increasing p21 levels via a p53-independent pathway. Overexpression of miR-1 down-regulated PAX3, a potential p21-regulating gene. Moreover, knockdown of PAX3 suppressed cell proliferation by increasing p21 levels, and induced arrest at the G₀/G₁ phase. Administration of miR-1 showed an in vivo antitumor effect.

CONCLUSION

Overexpression of miR-1 suppressed cell proliferation and induced arrest in the G₀/G₁ phase by increasing p21 levels via a p53-independent pathway through PAX3 suppression. These results indicate that miR-1 could be a therapeutic target for osteosarcoma.

Life-long reduction in myomiR expression does not adversely affect skeletal muscle morphology

We generated an inducible, skeletal muscle-specific Dicer knockout mouse to deplete microRNAs in adult skeletal muscle. Following tamoxifen treatment, Dicer mRNA expression was significantly decreased by 87%. Wild-type (WT) and Dicer knockout (KO) mice were subjected to either synergist ablation or hind limb suspension for two weeks. There was no difference in muscle weight with hypertrophy or atrophy between WT and KO groups; however, even with the significant loss of Dicer expression, myomiR (miR-1, -133a and -206) expression was only reduced by 38% on average. We next aged WT and KO mice for ~22 months following Dicer inactivation to determine if myomiR expression would be further reduced over a prolonged timeframe and assess the effects of myomiR depletion on skeletal muscle phenotype. Skeletal muscle Dicer mRNA expression remained significantly decreased by 80% in old KO mice and sequencing of cloned Dicer mRNA revealed the complete absence of the floxed exons in KO skeletal muscle. Despite a further reduction of myomiR expression to ~50% of WT, no change was observed in muscle morphology between WT and KO groups. These results indicate the life-long reduction in myomiR levels did not adversely affect skeletal muscle phenotype and suggest the possibility that microRNA expression is uniquely regulated in skeletal muscle.

Increased Expression of MicroRNA-206 Inhibits Potassium Voltage-Gated Channel Subfamily A Member 5 in Pulmonary Arterial Smooth Muscle Cells and Is Related to Exaggerated Pulmonary Artery Hypertension Following Intrauterine Growth Retardation in Rats

Background Intrauterine growth retardation ( IUGR ) is related to pulmonary artery hypertension in adults, and mi croRNA -206 (miR-206) is proposed to affect the proliferation and apoptosis of pulmonary artery smooth muscle cells ( PASMC s) via post-transcriptional regulation. Methods and Results In an IUGR rat model, we found that the expression and function of potassium voltage-gated channel subfamily A member 5 (Kv1.5) in PASMC s was inhibited, and pulmonary artery hypertension was exaggerated after chronic hypoxia ( CH ) treatment as adults. micro RNA expression was investigated in PASMC s from 12-week-old male IUGR rats with CH by microarray, polymerase chain reaction, and in situ hybridization. The expression levels of Kv1.5 in primary cultured PASMC s and pulmonary artery smooth muscle from IUGR or control rats were evaluated with and without application of an miR-206 inhibitor. Right ventricular systolic pressure, cell proliferation, luciferase reporter assay, and IKv were also calculated. We found increased expression of miR-206 in resistance pulmonary arteries of IUGR rats at 12 weeks compared with newborns. Application of an miR-206 inhibitor in vivo or in vitro increased expression of Kv1.5 α-protein and KCNA 5. Also, decreased right ventricular systolic pressure and cell proliferation were observed in PASMC s from 12-week-old control and IUGR rats after CH , while inhibitor did not significantly affect control and IUGR rats. Conclusions These results suggest that expression of Kv1.5 and 4-aminopyridine (Kv channel special inhibitor)-sensitive Kv current were correlated with the inhibition of miR-206 in PA rings of IUGR - CH rats and cultured IUGR PASMC s exposed to hypoxia. Thus, miR-206 may be a trigger for induction of exaggerated CH-pulmonary artery hypertension of IUGR via Kv1.5.

A Systematic Review of miR-29 in Cancer

MicroRNAs (miRNA) are small non-coding RNAs (∼22 nt in length) that are known as potent master regulators of eukaryotic gene expression. miRNAs have been shown to play a critical role in cancer pathogenesis, and the misregulation of miRNAs is a well-known feature of cancer. In recent years, miR-29 has emerged as a critical miRNA in various cancers, and it has been shown to regulate multiple oncogenic processes, including epigenetics, proteostasis, metabolism, proliferation, apoptosis, metastasis, fibrosis, angiogenesis, and immunomodulation. Although miR-29 has been thoroughly documented as a tumor suppressor in the majority of studies, some controversy remains with conflicting reports of miR-29 as an oncogene. In this review, we provide a systematic overview of miR-29's functional role in various mechanisms of cancer and introspection on the contradictory roles of miR-29.

PAX3: A Molecule with Oncogenic or Tumor Suppressor Function Is Involved in Cancer

Metastasis is the most deadly aspect of cancer and results from acquired gene regulation abnormalities in tumor cells. Transcriptional regulation is an essential component of controlling of gene function and its failure could contribute to tumor progression and metastasis. During cancer progression, deregulation of oncogenic or tumor suppressive transcription factors, as well as master cell fate regulators, collectively influences multiple steps of the metastasis cascade, including local invasion and dissemination of the tumor to distant organs. Transcription factor PAX3/Pax3, which contributes to diverse cell lineages during embryonic development, plays a major role in tumorigenesis. Mutations in this gene can cause neurodevelopmental disease and the existing literature supports that there is a potential link between aberrant expression of PAX3 genes in adult tissues and a wide variety of cancers. PAX3 function is tissue-specific and could contribute to tumorigenesis either directly as oncogene or as a tumor suppressor by losing its function. In this review, we discuss comprehensively the differential role played by PAX3 in various tissues and how its aberrant expression is implicated in disease development. This review particularly highlights the oncogenic and tumor suppressor role played by PAX3 in different cancers and underlines the importance of precisely identifying tissue-specific role of PAX3 in order to determine its exact role in development of cancer.

miR‑1 inhibits the progression of colon cancer by regulating the expression of vascular endothelial growth factor

MicroRNA (miR)-1 is associated with various human malignancies through repressing tumor growth, migration and angiogenesis. Recently, high-throughput transcriptional profiling confirmed that miR-1 is markedly downregulated in metastatic colorectal cancer; however, its biological functions and the specific underlying mechanisms in colorectal cancer (CRC) require further investigation. In this study, the expression of miR-1 in 111 CRC and paired normal tissue samples was measured using quantitative polymerase chain reaction analysis, and the association between miR-1 expression and clinical characteristics was evaluated. miR-1 was found to be significantly downregulated in CRC tissues compared with paired normal tissues, and in CRC cell lines compared with non-cancer cells (P<0.001), and was negatively associated with tumor size (P=0.001), differentiation (P=0.011), lymph node metastasis (P=0.001) and TNM stage (P=0.001). Further experiments revealed that miR-1 inhibited the migration and invasion of HCT116 and ClonA1 cells, and inhibited cell proliferation by affecting the cell cycle. Vascular endothelial growth factor (VEGF) was found to be a potential target of miR-1 by biological prediction, and further investigation confirmed that miR-1 significantly inhibited the expression and paracrine function of VEGF. In CRC tissues, the expression of VEGF was negatively correlated with miR-1. The low expression of miR-1 in CRC may be one of the reasons for the abnormally high expression of VEGF; the upregulation of miR-1 expression may inhibit cancer progression by downregulating VEGF. These findings indicate that treatment with miR-1 may be a novel method of tumor suppression, and provide a theoretical and experimental basis for the further targeted treatment of CRC through the regulation of miR-1 and VEGF expression.

Effect of miR-29b on the Proliferation and Apoptosis of Pulmonary Artery Smooth Muscle Cells by Targeting Mcl-1 and CCND2

The proliferation and apoptosis of pulmonary artery smooth muscle cells (PASMCs) are considered to be key steps in the progression of pulmonary arterial hypertension (PAH). MicroRNAs (e.g., miR-29b) have been identified in various diseases to be critical modulators of cell growth and apoptosis by targeting Mcl-1 and CCND2. However, the role of miR-29b in PAH remains unknown. So we try to investigate the effect of miR-29b on Mcl-1 and CCND2 protein in PASMCs, analyze the effect of miR-29b on the proliferation of PASMCs, and explore the significance of miR-29b in the proliferation, apoptosis, and gene therapy of PAH. It was observed that gene chip analysis showed miR-29b expression in pulmonary artery tissue. The expression of miR-29b was significantly reduced in PAH model mice. MiR-29b inhibited the proliferation of PASMCs and promoted the apoptosis of PASMCs. Mechanically, miR-29b could inhibit the expression of Mcl-1 and CCND2 protein and silenced Mcl-1 and CCND2 could abolish the change of proliferation and apoptosis of PASMCs. These results demonstrate that miR-29b suppressed cellular proliferation and promoted apoptosis of PASMCs, possibly through the inhibition of Mcl-1 and CCND2. Therefore, miR-29b may serve as a useful therapeutic tool to treat PAH.

PAX3-FOXO1 drives miR-486-5p and represses miR-221 contributing to pathogenesis of alveolar rhabdomyosarcoma

Rhabdomyosarcoma is the most common soft-tissue sarcoma in childhood and histologically resembles developing skeletal muscle. Alveolar rhabdomyosarcoma (ARMS) is an aggressive subtype with a higher rate of metastasis and poorer prognosis. The majority of ARMS tumors (80%) harbor a PAX3-FOXO1 or less commonly a PAX7-FOXO1 fusion gene. The presence of either the PAX3-FOXO1 or PAX7-FOXO1 fusion gene foretells a poorer prognosis resulting in clinical re-classification as either fusion-positive (FP-RMS) or fusion-negative RMS (FN-RMS). The PAX3/7-FOXO1 fusion genes result in the production of a rogue transcription factors that drive FP-RMS pathogenesis and block myogenic differentiation. Despite knowing the molecular driver of FP-RMS, targeted therapies have yet to make an impact for patients, highlighting the need for a greater understanding of the molecular consequences of PAX3-FOXO1 and its target genes including microRNAs. Here we show FP-RMS patient-derived xenografts and cell lines display a distinct microRNA expression pattern. We utilized both loss- and gain-of function approaches in human cell lines with knockdown of PAX3-FOXO1 in FP-RMS cell lines and expression of PAX3-FOXO1 in human myoblasts and identified microRNAs both positively and negatively regulated by the PAX3-FOXO1 fusion protein. We demonstrate PAX3-FOXO1 represses miR-221/222 that functions as a tumor suppressing microRNA through the negative regulation of CCND2, CDK6, and ERBB3. In contrast, miR-486-5p is transcriptionally activated by PAX3-FOXO1 and promotes FP-RMS proliferation, invasion, and clonogenic growth. Inhibition of miR-486-5p in FP-RMS xenografts decreased tumor growth, illustrating a proof of principle for future therapeutic intervention. Therefore, PAX3-FOXO1 regulates key microRNAs that may represent novel therapeutic vulnerabilities in FP-RMS.

Imprinting defects at human 14q32 locus alters gene expression and is associated with the pathobiology of osteosarcoma

Osteosarcoma is the most common primary bone malignancy affecting children and adolescents. Although several genetic predisposing conditions have been associated with osteosarcoma, our understanding of its pathobiology is rather limited. Here we show that, first, an imprinting defect at human 14q32-locus is highly prevalent (87%) and specifically associated with osteosarcoma patients < 30 years of age. Second, the average demethylation at differentially methylated regions (DMRs) in the 14q32-locus varied significantly compared to genome-wide demethylation. Third, the 14q32-locus was enriched in both H3K4-me3 and H3K27-me3 histone modifications that affected expression of all imprinted genes and miRNAs in this region. Fourth, imprinting defects at 14q32 - DMRs are present in triad DNA samples from affected children and their biological parents. Finally, imprinting defects at 14q32-DMRs were also observed at higher frequencies in an Rb1/Trp53 mutation-induced osteosarcoma mouse model. Further analysis of normal and tumor tissues from a Sleeping Beauty mouse model of spontaneous osteosarcoma supported the notion that these imprinting defects may be a key factor in osteosarcoma pathobiology. In conclusion, we demonstrate that imprinting defects at the 14q32 locus significantly alter gene expression, may contribute to the pathogenesis of osteosarcoma, and could be predictive of survival outcomes.

MicroRNAs in Different Histologies of Soft Tissue Sarcoma: A Comprehensive Review

Soft tissue sarcomas (STS) constitute a rare tumour entity comprising over 50 histological subtypes. MicroRNAs (miRNAs) are short non-protein coding RNA molecules that regulate gene expression by targeting the 3'-untranslated region of messenger RNAs. They are involved in a variety of human diseases, including malignancies, such as endometrial cancer, osteosarcoma, bronchial carcinoma and breast cancer. In STS, various miRNAs are differentially expressed, thus contributing to development, progression and invasion. Therefore, the aim of the present review is to summarise current knowledge on the role of miRNAs in STS. Furthermore, the potential role of miRNAs as diagnostic, prognostic and predictive biomarkers is discussed.

An Examination of the Role of Transcriptional and Posttranscriptional Regulation in Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is an aggressive family of soft tissue tumors that most commonly manifests in children. RMS variants express several skeletal muscle markers, suggesting myogenic stem or progenitor cell origin of RMS. In this review, the roles of both recently identified and well-established microRNAs in RMS are discussed and summarized in a succinct, tabulated format. Additionally, the subtypes of RMS are reviewed along with the involvement of basic helix-loop-helix (bHLH) proteins, Pax proteins, and microRNAs in normal and pathologic myogenesis. Finally, the current and potential future treatment options for RMS are outlined.

Safe and Effective Sarcoma Therapy through Bispecific Targeting of EGFR and uPAR

Sarcomas differ from carcinomas in their mesenchymal origin. Therapeutic advancements have come slowly, so alternative drugs and models are urgently needed. These studies report a new drug for sarcomas that simultaneously targets both tumor and tumor neovasculature. eBAT is a bispecific angiotoxin consisting of truncated, deimmunized Pseudomonas exotoxin fused to EGF and the amino terminal fragment of urokinase. Here, we study the drug in an in vivo "ontarget" companion dog trial as eBAT effectively kills canine hemangiosarcoma and human sarcoma cells in vitro We reasoned the model has value due to the common occurrence of spontaneous sarcomas in dogs and a limited lifespan allowing for rapid accrual and data collection. Splenectomized dogs with minimal residual disease were given one cycle of eBAT followed by adjuvant doxorubicin in an adaptive dose-finding, phase I-II study of 23 dogs with spontaneous, stage I-II, splenic hemangiosarcoma. eBAT improved 6-month survival from <40% in a comparison population to approximately 70% in dogs treated at a biologically active dose (50 μg/kg). Six dogs were long-term survivors, living >450 days. eBAT abated expected toxicity associated with EGFR targeting, a finding supported by mouse studies. Urokinase plasminogen activator receptor and EGFR are targets for human sarcomas, so thorough evaluation is crucial for validation of the dog model. Thus, we validated these markers for human sarcoma targeting in the study of 212 human and 97 canine sarcoma samples. Our results support further translation of eBAT for human patients with sarcomas and perhaps other EGFR-expressing malignancies. Mol Cancer Ther; 16(5); 956-65. ©2017 AACR.

MicroRNA-497 Induces Apoptosis and Suppresses Proliferation via the Bcl-2/Bax-Caspase9-Caspase3 Pathway and Cyclin D2 Protein in HUVECs

INTRODUCTION

MicroRNAs play crucial roles in various types of diseases. However, to date, no information about the role of miR-497 in the development of atherosclerosis has been reported. This study investigated the possible role of miR-497 in vascular endothelial cell injury during the early stage of atherosclerosis.

MATERIALS AND METHODS

The expression level of miR-497 in human umbilical vein endothelial cells (HUVECs) exposed to ox-LDL was detected using qRT-PCR. To perform gain of function and loss of function analyses, miR-497 mimics were transfected into HUVECs, and miR-497 inhibitors were transfected into HUVECs stimulated with ox-LDL. Flow cytometry was used to analyze cell cycle progression and apoptosis. EdU and CCK-8 assays were employed to detect DNA synthesis and cell proliferation, respectively. After bioinformatics prediction, a dual Luciferase Reporter assay was used to analyze the direct target genes of miR-497. The mRNA and protein levels of the target genes were detected using qRT-PCR and western blot analyses, respectively. Caspase-9/3 activity was analyzed to determine the mechanism of endothelial dysfunction.

RESULTS

We showed that miR-497 was significantly upregulated in HUVECs stimulated with ox-LDL. Ectopic expression of miR-497 suppressed cell proliferation, induced apoptosis and increased the activity of caspase-9/3. After verification, Bcl2 and CCND2 were shown to be direct target genes of miR-497 in HUVECs. MiR-497 significantly suppressed cell proliferation by arresting the cell cycle through the CCND2 protein and induced apoptosis through the Bcl2/Bax-caspase9-caspase3 pathway.

CONCLUSION

Overall, our study shows that miR-497 might play a role in the development of atherosclerosis by inducing apoptosis and suppressing the proliferation of vascular endothelial cells. Therefore, miR-497 could be a potential therapeutic target for the treatment of atherosclerosis.

Electroacupuncture induces acute changes in cerebral cortical miRNA profile, improves cerebral blood flow and alleviates neurological deficits in a rat model of stroke

Electroacupuncture has been shown to improve cerebral blood flow in animal models of stroke. However, it is unclear whether electroacupuncture alters miRNA expression in the cortex. In this study, we examined changes in the cerebral cortical miRNA profile, cerebral blood flow and neurological function induced by electroacupuncture in a rat model of stroke. Electroacupuncture was performed at Renzhong (GV26) and Neiguan (PC6), with a frequency of 2 Hz, continuous wave, current intensity of 3.0 mA, and stimulation time of 1 minute. Electroacupuncture increased cerebral blood flow and alleviated neurological impairment in the rats. miRNA microarray profiling revealed that the vascular endothelial growth factor signaling pathway, which links cell proliferation with stroke, was most significantly affected by electroacupuncture. Electroacupuncture induced changes in expression of rno-miR-206-3p, rno-miR-3473, rno-miR-6216 and rno-miR-494-3p, and these changes were confirmed by quantitative real-time polymerase chain reaction. Our findings suggest that changes in cell proliferation-associated miRNA expression induced by electroacupuncture might be associated with the improved cerebral blood supply and functional recovery following stroke.

MicroRNA and gene co-expression networks characterize biological and clinical behavior of rhabdomyosarcomas

Rhabdomyosarcomas (RMS) in children and adolescents are heterogeneous sarcomas broadly defined by skeletal muscle features and the presence/absence of PAX3/7-FOXO1 fusion genes. MicroRNAs are small non-coding RNAs that regulate gene expression in a cell context specific manner. Sequencing analyses of microRNAs in 64 RMS revealed expression patterns separating skeletal muscle, fusion gene positive and negative RMS. Integration with parallel gene expression data assigned biological functions to 12 co-expression networks/modules that reassuringly included myogenic roles strongly correlated with microRNAs known in myogenesis and RMS development. Modules also correlated with clinical outcome and fusion status. Regulation of microRNAs by the fusion protein was demonstrated after PAX3-FOXO1 reduction, exemplified by miR-9-5p. MiR-9-5p levels correlated with poor outcome, even within fusion gene positive RMS, and were higher in metastatic versus non-metastatic disease. MiR-9-5p reduction inhibited RMS cell migration. Our findings reveal microRNAs in a regulatory framework of biological and clinical significance in RMS.

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RNAseq profiled miRNA expression in 64 rhabdomyosarcomas (RMS).

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MiRNA expression distinguished muscle and RMS on the basis of fusion gene status.

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Co-expression networks linked to function, clinical data and fusion gene status.

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Identified miRNAs, including miR-9-5p, altered by the PAX3-FOXO1 fusion protein.

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Demonstrated clinical and functional role for miR-9-5p in RMS.

Epigenetic and genetic changes in soft tissue sarcomas: a review

Soft tissue sarcomas are a versatile group of tumors with a proposed origin from mesenchymal stem cells. During recent years, the molecular biologic mechanisms behind the histogenesis of these tumors have become clearer. In addition to translocations and other genomic changes, epigenetic mechanisms have been shown to be greatly involved in the histogenesis of sarcomas as well as other cancers. Even though the molecular mechanisms behind sarcomas appear to be more complex than previously expected, epigenetic mechanisms bring new opportunities and means for the treatment of these complex diseases.

Epigenetic regulation of SMARCB1 By miR-206, -381 and -671-5p is evident in a variety of SMARCB1 immunonegative soft tissue sarcomas, while miR-765 appears specific for epithelioid sarcoma. A miRNA study of 223 soft tissue sarcomas

Complete/partial loss of SMARCB1 nuclear-immunopositivity is characteristic of a certain subset of soft tissue sarcomas (STSs). Our previous work showed that oncomiRs-206,-381, and 671-5p could silence the SMARCB1 mRNA and protein expression and that they display significant overexpression in epithelioid sarcomas (ESs). MiR-765 was overexpressed too, but functionally was inactive in the silencing. In the current work, using quantitative PCR, we conducted a miRNA study of 51 ESs, 20 rhabdoid tumors (RTs), 20 synovial sarcomas (SSs), 15 malignant peripheral nerve sheath tumors (MPNSTs), 11 myoepithelial carcinomas (MECs), and 10 extraskeletal myxoid chondrosarcomas (EMCSs) with complete/partial loss of SMARCB1 nuclear immunostain, in contrast to controls (SMARCB1-immunopositive) of 96 STSs, 13 melanomas and 10 sarcomatoid carcinomas. The SMARCB1 genetic status of ESs was determined by MLPA and FISH. A subset of ESs (5/51) showed biallelic deletion of SMARCB1 with no overexpression of any miRNA, suggesting these tumors could be the counterpart of pediatric RT, at least genetically. Another subset (5/51) was genetically either intact or monoallelic deleted with at least threefold overexpression of one of miR-206,-381,-671-5p, suggesting epigenetic regulation only. 39/51 ESs had a biallelic deletion (>20% by FISH and/or by MLPA) but with overexpressed miR-206,-381, and 671-5p, suggesting intratumoral heterogeneity, i.e., both genetic and epigenetic regulation. At least threefold overexpression of one of miR-206,-381, and 671-5p was detected in all MPNSTs, EMCSs, SSs and 7 MCs. Except for ESs, four SSs and one MPNST, there was no event above threefold overexpression of miR-765 among all 195 tested tumors. Our results suggest a general role of miR-206,-381, and 671-5p in SMARCB1 gene silencing of ES, MC, EMCS, MPNST and SS. In the future, miR-765 could possibly be a diagnostic tool for ES because of its 97% specificity and 80% sensitivity. © 2016 Wiley Periodicals, Inc.

PAX7 is a required target for microRNA-206-induced differentiation of fusion-negative rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood. RMS can be parsed based on clinical outcome into two subtypes, fusion-positive RMS (FP-RMS) or fusion-negative RMS (FN-RMS) based on the presence or absence of either PAX3-FOXO1 or PAX7-FOXO1 gene fusions. In both RMS subtypes, tumor cells show histology and a gene expression pattern resembling that of developmentally arrested skeletal muscle. Differentiation therapy is an attractive approach to embryonal tumors of childhood including RMS; however, agents to drive RMS differentiation have not entered the clinic and their mechanisms remain unclear. MicroRNA-206 (miR-206) expression increases through normal muscle development and has decreased levels in RMS compared with normal skeletal muscle. Increasing miR-206 expression drives differentiation of RMS, but the target genes responsible for the relief of the development arrest are largely unknown. Using a combinatorial approach with gene and proteomic profiling coupled with genetic rescue, we identified key miR-206 targets responsible for the FN-RMS differentiation blockade, PAX7, PAX3, NOTCH3, and CCND2. Specifically, we determined that PAX7 downregulation is necessary for miR-206-induced cell cycle exit and myogenic differentiation in FN-RMS but not in FP-RMS. Gene knockdown of targets necessary for miR-206-induced differentiation alone or in combination was not sufficient to phenocopy the differentiation phenotype from miR-206, thus illustrating that miR-206 replacement offers the ability to modulate a complex network of genes responsible for the developmental arrest in FN-RMS. Genetic deletion of miR-206 in a mouse model of FN-RMS accelerated and exacerbated tumor development, indicating that both in vitro and in vivo miR-206 acts as a tumor suppressor in FN-RMS at least partially through downregulation of PAX7. Collectively, our results illustrate that miR-206 relieves the differentiation arrest in FN-RMS and suggests that miR-206 replacement could be a potential therapeutic differentiation strategy.

MiR-1 downregulation correlates with poor survival in clear cell renal cell carcinoma where it interferes with cell cycle regulation and metastasis

MicroRNAs (miRNA) that are strongly implicated in carcinogenesis have recently reshaped our understanding of the role of noncoding RNAs. Here, we focused on the function and molecular mechanism of miR-1 and its potential clinical application in clear cell renal cell carcinoma (ccRCC). First, miR-1 was significantly downregulated in 87.8% renal cancer samples compared with corresponding noncancerous tissues (NCT), which was significantly associated with clinical stage, T classification and poor overall survival. Functional study demonstrated that enforced overexpression of miR-1 in renal cancer cells inhibited proliferation and metastasis in vitro and in vivo. Conversely, miR-1 inhibitor silencing miR-1 expression promoted cell proliferation and metastasis in ccRCC. CDK4, CDK6, Caprin1 and Slug were each directly targeted for inhibition by miR-1 and restoring their expression reversed miR-1-mediated inhibition of cell cycle progression and metastasis. Taken together, our findings established a tumor suppressive role for miR-1 in the progression of ccRCC by targeting CDK4, CDK6, Caprin1 and Slug and suggested miR-1 can be served as a novel potential therapeutic target for ccRCC.

A selective screening platform reveals unique global expression patterns of microRNAs in a cohort of human soft-tissue sarcomas

Sarcomas are malignant heterogenous tumors of mesenchymal derivation. Emerging data suggest that miRNA might have a causal role in sarcomagenesis. Herein, we used a selective miRNA screening platform to study the comparative global miRNA expression signatures in a cohort of human sarcomas with the caveat that comparisons between tumor and non-tumor cells were performed from the same patients using formalin-fixed paraffin-embedded tissue. Five histologic types were examined that included: myxoid liposarcoma, well-differentiated liposarcoma, dedifferentiated liposarcoma, pleomorphic rhabdomyosarcoma, and synovial sarcoma. In addition, soft-tissue lipomas and normal fat were included as a separate set of controls for the lipogenic tumors. Clustering analysis showed a distinct global difference in expression patterns between the normal and sarcoma tissues. Expression signatures in an unsupervised hierarchical clustering analysis revealed tight clustering in synovial and myxoid liposarcomas, and the least clustering was observed in the pleomorphic rhabdomyosarcoma subtype. MiR-145 showed underexpression in pleomorphic rhabdomyosarcoma, well-differentiated liposarcoma, and synovial sarcoma. Unexpectedly, we found that a set of muscle-specific microRNAs (miRNAs; myomiRs): miR-133, miR-1, and miR-206 was significantly underexpressed in well-differentiated liposarcoma and synovial sarcoma, suggesting that they may function as tumor suppressors as described in muscle-relevant rhabdomyosarcomas. In addition, a tight linear progression of miRNA expression was identified from normal fat to dedifferentiated liposarcoma. These results suggest that miRNA expression profiles could elucidate classes of miRNAs that may elicit tumor-relevant activities in specific sarcoma subtypes.

SMYD1 and G6PD modulation are critical events for miR-206-mediated differentiation of rhabdomyosarcoma

Rhadomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood. RMS cells resemble fetal myoblasts but are unable to complete myogenic differentiation. In previous work we showed that miR-206, which is low in RMS, when induced in RMS cells promotes the resumption of differentiation by modulating more than 700 genes. To better define the pathways involved in the conversion of RMS cells into their differentiated counterpart, we focused on 2 miR-206 effectors emerged from the microarray analysis, SMYD1 and G6PD. SMYD1, one of the most highly upregulated genes, is a H3K4 histone methyltransferase. Here we show that SMYD1 silencing does not interfere with the proliferative block or with the loss anchorage independence imposed by miR-206, but severely impairs differentiation of ERMS, ARMS, and myogenic cells. Thus SMYD1 is essential for the activation of muscle genes. Conversely, among the downregulated genes, we found G6PD, the enzyme catalyzing the rate-limiting step of the pentose phosphate shunt. In this work, we confirmed that G6PD is a direct target of miR-206. Moreover, we showed that G6PD silencing in ERMS cells impairs proliferation and soft agar growth. However, G6PD overexpression does not interfere with the pro-differentiating effect of miR-206, suggesting that G6PD downmodulation contributes to - but is not an absolute requirement for - the tumor suppressive potential of miR-206. Targeting cancer metabolism may enhance differentiation. However, therapeutic inhibition of G6PD is encumbered by side effects. As an alternative, we used DCA in combination with miR-206 to increase the flux of pyruvate into the mitochondrion by reactivating PDH. DCA enhanced the inhibition of RMS cell growth induced by miR-206, and sustained it upon miR-206 de-induction. Altogether these results link miR-206 to epigenetic and metabolic reprogramming, and suggest that it may be worth combining differentiation-inducing with metabolism-directed approaches.