LncRNA CASC15 is Upregulated in Osteosarcoma Plasma Exosomes and CASC15 Knockdown Inhibits Osteosarcoma Progression by Regulating miR-338-3p/RAB14 Axis

Osteosarcoma in a ceRNET perspective

Osteosarcoma (OS) is the most prevalent and fatal type of bone tumor. It is characterized by great heterogeneity of genomic aberrations, mutated genes, and cell types contribution, making therapy and patients management particularly challenging. A unifying picture of molecular mechanisms underlying the disease could help to transform those challenges into opportunities.This review deeply explores the occurrence in OS of large-scale RNA regulatory networks, denominated "competing endogenous RNA network" (ceRNET), wherein different RNA biotypes, such as long non-coding RNAs, circular RNAs and mRNAs can functionally interact each other by competitively binding to shared microRNAs. Here, we discuss how the unbalancing of any network component can derail the entire circuit, driving OS onset and progression by impacting on cell proliferation, migration, invasion, tumor growth and metastasis, and even chemotherapeutic resistance, as distilled from many studies. Intriguingly, the aberrant expression of the networks components in OS cells can be triggered also by the surroundings, through cytokines and vesicles, with their bioactive cargo of proteins and non-coding RNAs, highlighting the relevance of tumor microenvironment. A comprehensive picture of RNA regulatory networks underlying OS could pave the way for the development of innovative RNA-targeted and RNA-based therapies and new diagnostic tools, also in the perspective of precision oncology.

Exploring the Impact of Exosomal Cargos on Osteosarcoma Progression: Insights into Therapeutic Potential

Osteosarcoma (OS) is a primary malignant bone tumor with high metastasis. Poor prognosis highlights a clinical need for novel therapeutic strategies. Exosomes, also known as extracellular vesicles, have been identified as essential players in the modulation of cancer. Recent studies have suggested that OS-derived exosomes can drive pro-tumorigenic or anti-tumorigenic phenotypes by transferring specific cargos, including proteins, nucleic acids, and metabolites, to neighboring cells, significantly impacting the regulation of cellular processes. This review discusses the advancement of exosomes and their cargos in OS. We examine how these exosomes contribute to the modulation of cellular phenotypes associated with tumor progression and metastasis. Furthermore, we explore the potential of exosomes as valuable biomarkers for diagnostics and prognostic purposes and their role in shaping innovative therapeutic strategies in OS treatment development.

Extracellular vesicles in tumorigenesis, metastasis, chemotherapy resistance and intercellular communication in osteosarcoma

HIGHLIGHTS

Extracellular vehicles play crucial function in osteosarcoma tumorigenesis.Extracellular vehicles mediated the intercellular communication of osteosarcoma cells with other types cells in tumor microenvironment.Extracellular vehicles have potential utility in osteosarcoma diagnosis and treatment.

Unveiling the functional paradigm of exosome-derived long non-coding RNAs (lncRNAs) in cancer: based on a narrative review and systematic review

BACKGROUND AND PURPOSE

The intricate mechanisms underlying intercellular communication within the tumor microenvironment remain largely elusive. Recently, attention has shifted towards exploring the intercellular signaling mediated by exosomal long non-coding RNAs (lncRNAs) within this context. This comprehensive systematic review aims to elucidate the functional paradigm of exosome-derived lncRNAs in cancer.

MATERIALS AND METHODS

The review provides a comprehensive narrative of lncRNA definition, characteristics, as well as the formation, sorting, and uptake processes of exosome-derived lncRNAs. Additionally, it describes comprehensive technology for exosome research and nucleic acid drug loading. This review further systematically examines the cellular origins, functional roles, and underlying mechanisms of exosome-derived lncRNAs in recipient cells within the cancer setting.

RESULTS

The functional paradigm of exosome-derived lncRNAs in cancer mainly depends on the source cells and sorting mechanism of exosomal lncRNAs, the recipient cells and uptake mechanisms of exosomal lncRNAs, and the specific molecular mechanisms of lncRNAs in recipient cells. The source cells of exosomal lncRNAs mainly involved in the current review included tumor cells, cancer stem cells, normal cells, macrophages, and cancer-associated fibroblasts.

CONCLUSION

This synthesis of knowledge offers valuable insights for accurately identifying exosomal lncRNAs with potential as tumor biomarkers. Moreover, it aids in the selection of appropriate targeting strategies and preclinical models, thereby facilitating the clinical translation of exosomal lncRNAs as promising therapeutic targets against cancer. Through a comprehensive understanding of the functional role of exosome-derived lncRNAs in cancer, this review paves the way for advancements in personalized medicine and improved treatment outcomes.

Exosome-Based Liquid Biopsy Approaches in Bone and Soft Tissue Sarcomas: Review of the Literature, Prospectives, and Hopes for Clinical Application

The knowledge of exosome impact on sarcoma development and progression has been implemented in preclinical studies thanks to technological advances in exosome isolation. Moreover, the clinical relevance of liquid biopsy is well established in early diagnosis, prognosis prediction, tumor burden assessment, therapeutic responsiveness, and recurrence monitoring of tumors. In this review, we aimed to comprehensively summarize the existing literature pointing out the clinical relevance of detecting exosomes in liquid biopsy from sarcoma patients. Presently, the clinical utility of liquid biopsy based on exosomes in patients affected by sarcoma is under debate. The present manuscript collects evidence on the clinical impact of exosome detection in circulation of sarcoma patients. The majority of these data are not conclusive and the relevance of liquid biopsy-based approaches in some types of sarcoma is still insufficient. Nevertheless, the utility of circulating exosomes in precision medicine clearly emerged and further validation in larger and homogeneous cohorts of sarcoma patients is clearly needed, requiring collaborative projects between clinicians and translational researchers for these rare cancers.

The Roles of Exosomes in Metastasis of Sarcoma: From Biomarkers to Therapeutic Targets

Sarcoma is a heterogeneous group of mesenchymal neoplasms with a high rate of lung metastasis. The cellular mechanisms responsible for sarcoma metastasis remain poorly understood. Furthermore, there are limited efficacious therapeutic strategies for treating metastatic sarcoma. Improved diagnostic and therapeutic modalities are of increasing importance for the treatment of sarcoma due to their high mortality in the advanced stages of the disease. Recent evidence demonstrates that the exosome, a type of extracellular vesicle released by virtually all cells in the body, is an important facilitator of intercellular communication between the cells and the surrounding environment. The exosome is gaining significant attention among the medical research community, but there is little knowledge about how the exosome affects sarcoma metastasis. In this review, we summarize the multifaceted roles of sarcoma-derived exosomes in promoting the process of metastasis via the formation of pre-metastatic niche (PMN), the regulation of immunity, angiogenesis, vascular permeability, and the migration of sarcoma cells. We also highlight the potential of exosomes as innovative diagnostic and prognostic biomarkers as well as therapeutic targets in sarcoma metastasis.

A study of the prognostic value of long non-coding RNA CASC15 in human solid tumors utilizing The Cancer Genome Atlas (TCGA) datasets and a meta-analysis

BACKGROUND AND AIMS

Several malignant solid tumors have been reported to have an abnormal expression of the long non-coding RNA CASC15 (lncRNA CASC15). However, the clinicopathologic and prognostic importance of CASC15 in solid tumors are unknown. As a result, we examined the interrelationship between CASC15, overall survival length, and clinicopathological attributes of cancers affecting humans by analyzing various studies and The Cancer Genome Atlas (TCGA) data related to CASC15 expression.

METHODS

Web of Science, PubMed, Cochrane Library, Embase, Chinese WanFang, and Chinese CNKI databases were used to conduct a literature search. Hazard ratios (HRs) and Pooled odds ratios (ORs) were calculated taking 95% confidence intervals (CIs). The results of the current meta-analysis were further validated using TCGA datasets.

RESULTS

A total of 12 eligible studies enrolling 767 patients were included in this meta-analysis. Findings of the analysis showed that CASC15 expression had a significant relation to the metastasis of lymph node (OR = 3.30, 95%CI = 1.88-5.81, p < 0.001), distant metastasis (OR = 2.64, 95%CI = 1.24-5.63, p = 0.012), and high TNM/clinical stage (OR = 2.67, 95%CI = 1.34-5.32, p = 0.005). Additionally, we found that a poor outcome for overall survival (OS) was predicted by an elevation in CASC15 expression (HR = 2.01, 95%CI = 1.71-2.36, p < 0.001). Further investigation of the TCGA dataset revealed that CASC15 had abnormal expression in many cancers, which at least partially validated the findings of the current meta-analysis.

CONCLUSIONS

According to the latest meta-analysis and systematic review, high expression levels of CASC15 are associated with poor survival outcomes for solid tumor patients, and the use of CASC15 as a solid tumor prognostic predictor has a solid theoretical foundation.

LncRNA-CASC15 knockdown inhibits the progression of esophageal squamous cell carcinoma through targeting miR-33a-5p/PTGS2 axis

LncRNA CASC15 has been determined as a novel tumor-related lncRNA in many cancers. However, the in-detail role of CASC15 remains elusive in esophageal squamous cell carcinoma (ESCC). CASC15 expression level was detected in 113 ESCC tissues and paired adjacent normal tissues and in human ESCC cell lines. The effects of CASC15 on ESCC proliferation, migration, and invasion were assessed using CCK-8 and transwell assays. In addition, the potential downstream molecules of CASC15 were searched and confirmed by software algorithms, RT-qPCR, western blot, dual-luciferase reporter, and rescue experiments. CASC15 was upregulated in ESCC tissues and cell lines. CASC15 overexpression was associated with poorer prognosis in ESCC patients. Functionally, CASC15 knockdown inhibited cell proliferation, migration, and invasion of ESCC cells. Mechanistically, it was confirmed that CASC15 acts as competing endogenous RNA for miR-33a-5p to regulate PTGS2 expression. In addition, rescue assay showed that miR-33a-5p knockdown or PTGS2 overexpression abolished the cell proliferation, migration, and invasion inhibition role of CASC15 knockdown. In conclusion, this study indicates that CASC15 was upregulated in ESCC and CASC15 knockdown hindered ESCC progression through targeting the miR-33a-5p/PTGS2 axis. CASC15 might serve as a novel biomarker and therapeutic target for ESCC.

Exosomes in sarcoma: Prospects for clinical applications

Sarcoma is a group of rare and heterogeneous mesenchymal tumors, prone to late diagnosis and poor prognosis. Exosomes are cell-derived small extracellular vesicles found in most body fluids and contain nucleic acids, proteins, lipids, and other molecules. Qualitative and quantitative changes of exosomes and the contents are associated with sarcoma progression, exhibiting their potential as biomarkers. Exosomes possess the capacity of evading immune responses, bioactivity for trafficking, tumor tropism, and lesion residence. Thus, exosomes could be engineered as tumor-specific vehicles in drugs and RNA delivery systems. Exosomes might also serve as therapeutic targets in targeted therapy and immunotherapy and be involved in chemotherapy resistance. Here, we provide a comprehensive summary of exosome applications in liquid biopsy-based diagnosis and explore their implications in the delivery system, targeted therapy, and chemotherapy resistance of sarcoma. Moreover, challenges in exosome clinical applications are raised and some future research directions are proposed.

Silencing of lncRNA KLF3-AS1 represses cell growth in osteosarcoma via miR-338-3p/MEF2C axis

BACKGROUND

Osteosarcoma (OS) is a highly recurrent malignancy occurring among adolescents. The goal of this research was to scrutinize the role and action mechanism of KLF3-AS1 in OS.

METHODS

Western blotting and quantitative reverse transcription real-time PCR were conducted to ascertain the mRNA expressions of miR-338-3p, KLF3-AS1, and MEF2C in OS cell lines and tissue samples. Colony formation and CCK-8 experiments were done to evaluate the proliferative capacity of the cells. Western blotting was also executed to measure the relative expressions of the proteins Bcl-2 and Bax. RNA immunoprecipitation and dual luciferase reporter experiments were carried out to validate the target relationships among MEF2C, KLF3-AS1, and miR-338-3p. Mouse xenograft models were created to assess the influences of KLF3-AS1 on the growth of tumors in vivo.

RESULTS

Elevated levels of KLF3-AS1 and MEF2C and reduced amounts of miR-338-3p were identified in OS. KLF3-AS1 targeted miR-338-3p, and miR-338-3p further targeted MEF2C. Silencing KLF3-AS1 induced apoptosis and attenuated proliferation in vitro and repressed the tumor growth in vivo. Inhibiting miR-338-3p inverted the cancer-suppressing effects of KLF3-AS1 silencing. Meanwhile, loss of MEF2C partially eliminated the effects brought about by miR-338-3p downregulation, namely the stimulation of cell growth and suppression of apoptosis.

CONCLUSIONS

Silencing of KLF3-AS1 could repress the growth of cells and induce apoptosis by regulating miR-338-3p/MEF2C in OS. This suggests that the regulatory axis KLF3-AS1/miR-338-3p/MEF2C is a prospective target for OS treatment.

Extracellular vesicles: A new diagnostic biomarker and targeted drug in osteosarcoma

Osteosarcoma (OS) is a primary bone cancer that is highly prevalent among adolescents and adults below the age of 20 years. The prognostic outcome of metastatic OS or relapse is extremely poor; thus, developing new diagnostic and therapeutic strategies for treating OS is necessary. Extracellular vesicles (EVs) ranging from 30–150 nm in diameter are commonly produced in different cells and are found in various types of body fluids. EVs are rich in biologically active components like proteins, lipids, and nucleic acids. They also strongly affect pathophysiological processes by modulating the intercellular signaling pathways and the exchange of biomolecules. Many studies have found that EVs influence the occurrence, development, and metastasis of osteosarcoma. The regulation of inflammatory communication pathways by EVs affects OS and other bone-related pathological conditions, such as osteoarthritis and rheumatoid arthritis. In this study, we reviewed the latest findings related to diagnosis, prognosis prediction, and the development of treatment strategies for OS from the perspective of EVs.

Exosomes in the tumor microenvironment of sarcoma: from biological functions to clinical applications

The current diagnosis and treatment of sarcoma continue to show limited timeliness and efficacy. In order to enable the early detection and management of sarcoma, increasing attentions have been given to the tumor microenvironment (TME). TME is a dynamic network composed of multiple cells, extracellular matrix, vasculature, and exosomes. Exosomes are nano-sized extracellular vesicles derived from various cells in the TME. The major function of exosomes is to promote cancer progress and metastasis through mediating bidirectional cellular communications between sarcoma cells and TME cells. Due to the content specificity, cell tropism, and bioavailability, exosomes have been regarded as promising diagnostic and prognostic biomarkers, and therapeutic vehicles for sarcoma. This review summarizes recent studies on the roles of exosomes in TME of sarcoma, and explores the emerging clinical applications.

KLF5 promotes KIF1A expression through transcriptional repression of microRNA-338 in the development of pediatric neuroblastoma

BACKGROUND

Neuroblastoma (NB) comprises about 8-10% of pediatric cancers, and microRNA (miR)-338 downregulation has been implicated in NB. However, the underlying molecular mechanism remains largely unclear. The main goal of this study is to probe the regulatory role of miR-338 and the upstream and downstream biomolecules involved in NB.

METHODS

The differentially expressed miRNAs were screened by analyzing the NB gene expression microarray GSE121513 from the GEO database, and the differences in expression of the screened miRNAs were verified in clinically collected NB tissues versus dorsal root ganglions. Subsequently, the relationship between the miR-338 expression and NB cell growth was validated in vitro and in vivo, and the upstream and downstream regulatory mechanisms of miR-338 were further analyzed by bioinformatics. Functional rescue experiments were used to verify their effects on NB cell growth.

RESULTS

miR-338 expressed poorly in NB tissues, and overexpression of miR-338 significantly inhibited NB cell growth in vitro and in vivo. The prediction results showed that miR-338 could target KIF1A, and miR-338 expression was negatively correlated with the expression of KIF1A. We further found that miR-338 was transcriptionally regulated by the transcription factor KLF5. Overexpression of KLF5 or KIF1A significantly attenuated the inhibitory effect of miR-338 mimic on NB cell growth. Finally, miR-338 blocked the Hedgehog signaling pathway by inhibiting the expression of KIF1A.

CONCLUSION

Overexpression of KLF5 reduced expression of miR-338, which in turn increased the expression of KIF1A and activated the Hedgehog signaling pathway, leading to the progression of NB.

Bone mesenchymal stem cell-derived extracellular vesicles containing NORAD promote osteosarcoma by miR-30c-5p

Osteosarcoma is a bone tumor that often affects children, adolescents and young people. Non-coding RNA activated by DNA damage (NORAD) can promote the proliferation of cancer cells in multiple tumors. Thus, the current study set out to explore the role of NORAD derived from extracellular vesicles (EVs) of bone mesenchymal stem cells (BMSCs) in osteosarcoma. First, NORAD was highly expressed in osteosarcoma cells and tissues, which might be associated with the progression and metastasis of osteosarcoma. We isolated EVs from the characterized BMSCs, and found that NORAD was transferred from BMSCs to osteosarcoma cells via EVs in the co-culture system. Consequently, NORAD delivered by BMSC-derived EVs promoted the proliferation and invasion of osteosarcoma cells. Subsequently, bioinformatics analyses suggested potential binding relationship between NORAD and microRNA-30c-5p (miR-30c-5p) as well as between miR-30c-5p and Krueppel-like factor 10 (KLF10), and the results of which were further verified by dual luciferase reporter gene assay, RNA immunoprecipitation, and RNA pull-down assay. Mechanistically, NORAD acted as a sponge of miR-30c-5p and up-regulated the expression of KLF10 where miR-30-c-5p mimic declined the effect induced by NORAD on cancer cells. The osteosarcoma cells were injected into mice to develop tumor growth and metastasis models. In these two models, injection of BMSC-EVs elevated NORAD expression and KLF10 but reduced miR-30c-5p expression, whereby suppressing tumor growth and lung metastasis. To conclude, BMSC-EVs deliver NORAD to osteosarcoma cells to regulate the miR-30c-5p/KLF10 axis, thereby accelerating the progression and metastasis of osteosarcoma.

Emerging role of exosomes in cancer progression and tumor microenvironment remodeling

Cancer is one of the leading causes of death worldwide, and the factors responsible for its progression need to be elucidated. Exosomes are structures with an average size of 100 nm that can transport proteins, lipids, and nucleic acids. This review focuses on the role of exosomes in cancer progression and therapy. We discuss how exosomes are able to modulate components of the tumor microenvironment and influence proliferation and migration rates of cancer cells. We also highlight that, depending on their cargo, exosomes can suppress or promote tumor cell progression and can enhance or reduce cancer cell response to radio- and chemo-therapies. In addition, we describe how exosomes can trigger chronic inflammation and lead to immune evasion and tumor progression by focusing on their ability to transfer non-coding RNAs between cells and modulate other molecular signaling pathways such as PTEN and PI3K/Akt in cancer. Subsequently, we discuss the use of exosomes as carriers of anti-tumor agents and genetic tools to control cancer progression. We then discuss the role of tumor-derived exosomes in carcinogenesis. Finally, we devote a section to the study of exosomes as diagnostic and prognostic tools in clinical courses that is important for the treatment of cancer patients. This review provides a comprehensive understanding of the role of exosomes in cancer therapy, focusing on their therapeutic value in cancer progression and remodeling of the tumor microenvironment.

Identification of key serum biomarkers for the diagnosis and metastatic prediction of osteosarcoma by analysis of immune cell infiltration

Background

The role of circular RNAs (circRNAs) and microRNAs (miRNAs) in osteosarcoma (OS) development has not been fully elucidated. Further, the contribution of the immune response to OS progression is not well defined. However, it is known that circRNAs and miRNAs can serve as biomarkers for the diagnosis, prognosis, and therapy of many cancers. Thus, the aim of this study was to identify novel key serum biomarkers for the diagnosis and metastatic prediction of OS by analysis of immune cell infiltration and associated RNA molecules.

Methods

Human OS differentially expressed circRNAs (DEcircRNAs), differentially expressed miRNAs (DEmiRNAs), and differentially expressed mRNAs (DEmRNAs) were identified by analysis of microarray data downloaded from Gene Expression Omnibus (GEO) datasets. Further, characteristic patterns of OS-infiltrating immune cells were analyzed. On this basis, we identified statistically significant transcription factors. Moreover we performed pathway enrichment analysis, constructed protein–protein interaction networks, and devised competitive endogenous RNA (ceRNA) networks. Biological targets of the ceRNA networks were evaluated and potential OS biomarkers confirmed by RT-qPCR analysis of the patients’ serum.

Results

Seven differentially expressed circRNAs, 166 differentially expressed miRNAs, and 175 differentially expressed mRNAs were identified. An evaluation of cellular OS infiltration identified the highest level of infiltration by M0 macrophages, M2 macrophages, and CD8+ T cells, with M0 macrophages and CD8+ T cells as the most prominent. Significant patterns of tumor-infiltrating immune cells were identified by principal component analysis. Moreover, 185 statistically significant transcription factors were associated with OS. Further, in association with immune cell infiltration, hsa-circ-0010220, hsa-miR-326, hsa-miR-338-3p, and FAM98A were identified as potential novel biomarkers for OS diagnosis. Of these, FAM98A had the most promise as a diagnostic marker for OS and OS metastasis. Most importantly, a novel diagnostic model consisting of these four biomarkers (hsa-circ-0010220, hsa-miR-326, hsa-miR-338-3p, and FAM98A) was established with a 0.928 AUC value.

Conclusions

In summary, potential serum biomarkers for OS diagnosis and metastatic prediction were identified based on an analysis of immune cell infiltration. A novel diagnostic model consisting of these four promising serum biomarkers was established. Taken together, the results of this study provide a new perspective by which to understand immunotherapy of OS.

Role of extracellular vesicles in osteosarcoma

Osteosarcoma is a malignant bone tumor characterized by the direct production of osteoid tissue from tumor cells. Extracellular vesicles are membranous vesicles released by cells into the extracellular matrix, which exist widely in various body fluids and cell supernatants, and stably carry some important signaling molecules. They are involved in cell communication, cell migration, angiogenesis and tumor cell growth. Increasing evidence has shown that extracellular vesicles play a significant role in osteosarcoma development, progression, and metastatic process, indicating that extracellular vesicles can be use as biomarker vehicles in the diagnosis and prognosis of osteosarcoma. This review discusses the basic biological characteristics of extracellular vesicles and focuses on their application in osteosarcoma.

Osteosarcoma and Metastasis

Osteosarcoma is the most common primary bone malignancy in adolescents. Its high propensity to metastasize is the leading cause for treatment failure and poor prognosis. Although the research of osteosarcoma has greatly expanded in the past decades, the knowledge and new therapy strategies targeting metastatic progression remain sparse. The prognosis of patients with metastasis is still unsatisfactory. There is resonating urgency for a thorough and deeper understanding of molecular mechanisms underlying osteosarcoma to develop innovative therapies targeting metastasis. Toward the goal of elaborating the characteristics and biological behavior of metastatic osteosarcoma, it is essential to combine the diverse investigations that are performed at molecular, cellular, and animal levels from basic research to clinical translation spanning chemical, physical sciences, and biology. This review focuses on the metastatic process, regulatory networks involving key molecules and signaling pathways, the role of microenvironment, osteoclast, angiogenesis, metabolism, immunity, and noncoding RNAs in osteosarcoma metastasis. The aim of this review is to provide an overview of current research advances, with the hope to discovery druggable targets and promising therapy strategies for osteosarcoma metastasis and thus to overcome this clinical impasse.

Exosomes as Efficient Nanocarriers in Osteosarcoma: Biological Functions and Potential Clinical Applications

Osteosarcoma is the most common bone tumor affecting both adolescents and children. Although localized osteosarcoma has an overall survival of >70% in the clinic, metastatic, refractory, and recurrent osteosarcoma have poorer survival rates. Exosomes are extracellular vesicles released by cells and originally thought to be a way for cells to discard unwanted products. Currently, exosomes have been reported to be involved in intercellular cross-talk and induce changes in cellular behavior by transferring cargoes (proteins, DNA, RNA, and lipids) between cells. Exosomes regulate osteosarcoma progression, and processes such as tumorigenesis, proliferation, metastasis, angiogenesis, immune evasion, and drug resistance. Increasing evidences shows that exosomes have significant potential in promoting osteosarcoma progression and development. In this review, we describe the current research status of exosomes in osteosarcoma, focusing on the biological functions of osteosarcoma exosomes as well as their application in osteosarcoma as diagnostic biomarkers and therapeutic targets.

Exosomal miR-338-3p suppresses non-small-cell lung cancer cells metastasis by inhibiting CHL1 through the MAPK signaling pathway

Globally, lung cancer remains one of the most prevalent malignant cancers. However, molecular mechanisms and functions involved in its pathogenesis have not been clearly elucidated. This study aimed to evaluate the specific regulatory mechanisms of exosomal miR-338-3p/CHL1/MAPK signaling pathway axis in non-small-cell lung cancer. Western blotting and qRT-PCR (reverse transcription-polymerase chain reaction) were used to determine the expression levels of CHL1 and exosomal miR-338-3p in NSCLC (non-small-cell lung cancer). The CHL1 gene was upregulated and downregulated to evaluate its functions in NSCLC progression. In vitro MTS and apoptotic assays were used to investigate the functions of CHL1 and exosomal miR-338-3p in NSCLC progression. The high-throughput sequencing was used to explore differently expressed exosomal miRNAs. The biological relationships between MAPK signaling pathway and CHL1 and exosomal miR-338-3p in NSCLC were predicted through bioinformatics analyses and verified by western blotting. Elevated CHL1 levels were observed in NSCLC tissues and cells. Upregulated CHL1 expression enhanced NSCLC cells’ progression by promoting tumor cells proliferation while suppressing their apoptosis. Conversely, the downregulation of the CHL1 gene inhibited NSCLC cells’ growth and promoted tumor cells’ apoptotic rate. Additionally, CHL1 activated the MAPK signaling pathway. Besides, we confirmed that miR-338-3p directly sponged with CHL1 to mediate tumor cells progression. Moreover, exosomal miR-338-3p serum levels in NSCLC patients were found to be low. BEAS-2B cells can transfer exosomal miR-338-3p to A549 cells and SK-MES-1 cells. In addition, elevated exosomal miR-338-3p levels significantly inhibited tumor cells proliferation and promoted their apoptosis by suppressing activation of the MAPK signaling pathway. Exosomal miR-338-3p suppresses tumor cells' metastasis by downregulating the expression of CHL1 through MAPK signaling pathway inactivation.

LncRNA CASC15 Promotes Cerebral Ischemia/Reperfusion Injury via miR-338-3p/ETS1 Axis in Acute Ischemic Stroke

Purpose

Acute ischemic stroke (AIS) is a leading health problem caused by cerebral ischemia/reperfusion (CI/R). This study aimed to unveil the potential clinical value and mechanism of lncRNA CASC15.

Patients and Methods

The expression of CASC15, miR-338-3p was detected by quantitative real-time PCR (qRT-PCR). The correlations between CASC15 and national institutes of health stroke scale (NIHSS) scores or miR-338-3p were evaluated by Pearson correlation. A receiver operating characteristic (ROC) curve was performed to provide the diagnostic value of CASC15. Cell Counting Kit-8 (CCK-8) and flow cytometer were used to detect the condition of cell viability and apoptosis. The levels of interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) was detected by enzyme-linked immunosorbent assay (ELISA) assay.

Results

The expression of CASC15 was increased and the levels of miR-338-3p were decreased in AIS patients. A positive association between CASC15 and NIHSS score and an inverse association between CASC15 and miR-338-3p were revealed by Pearson correlation. CASC15 might discriminate AIS patients from healthy people. Silenced CASC15 exerted neuroprotective roles on cell viability, apoptosis, and inflammation via the miR-338-3p/ETS1 axis.

Conclusion

CASC15 might act as a potential diagnostic biomarker for AIS patients. CASC15/miR-338-3p/ETS1 axis played an essential role in cell viability, apoptosis, and neuroinflammation.

circUSP34 accelerates osteosarcoma malignant progression by sponging miR-16-5p

Osteosarcoma (OS) is a primary and highly malignant mesenchymal tissue tumor. The specific pathological mechanism underlying disease initiation or progression remains unclear. Circular RNAs (circRNAs) are a type of covalently circular RNA with a head-to-tail junction site. In this study, we aimed to investigate the sponging mechanism between circRNAs and microRNAs (miRNAs) in OS. Based on the inhibited effect of miR-16-5p reported on OS, circUSP34 was analyzed as a sponge of miR-16-5p via Starbase. We found that circUSP34 promoted the proliferation, migration, and invasion of OS in vitro and in vivo. circUSP34 increased but miR-16-5p decreased in OS by qRT-PCR. Function assays showed that the malignancy of OS cells, including proliferation, migration, and invasion, was inhibited after knocking out circUSP34. Western blotting results showed that the expression level of vimentin and Ki-67 decreased. Similarly, miR-16-5p mimic compromised the proliferation, migration, and invasion of OS cells. FISH assay results indicated that circUSP34 and miR-16-5p were colocalized in the cytoplasm. The sponging mechanism of circUSP34 and miR-16-5p was verified by dual-luciferase reporter assay, RNA immunoprecipitation (RIP), and RNA pull down assays. Interestingly, the miR-16-5p inhibitor partly reversed the inhibitory effect of sh-circUSP34 on the malignancy of OS cells. Further, mice tumors for IHC indicated that vimentin, N-cadherin, and Ki-67 protein expression decreased, but E-cadherin protein expression increased. Collectively, circUSP34 promoted OS malignancy, including proliferation, migration, and invasion, by sponging miR-16-5p. It can serve as a potential therapeutic target and biomarker.

The basic characteristics of extracellular vesicles and their potential application in bone sarcomas

Bone sarcomas are rare cancers accompanied by metastatic disease, mainly including osteosarcoma, Ewing sarcoma and chondrosarcoma. Extracellular vesicles (EVs) are membrane vesicles released by cells in the extracellular matrix, which carry important signal molecules, can stably and widely present in various body fluids, such as plasma, saliva and scalp fluid, spinal cord, breast milk, and urine liquid. EVs can transport almost all types of biologically active molecules (DNA, mRNA, microRNA (miRNA), proteins, metabolites, and even pharmacological compounds). In this review, we summarized the basic biological characteristics of EVs and focused on their application in bone sarcomas. EVs can be use as biomarker vehicles for diagnosis and prognosis in bone sarcomas. The role of EVs in bone sarcoma has been analyzed point-by-point. In the microenvironment of bone sarcoma, bone sarcoma cells, mesenchymal stem cells, immune cells, fibroblasts, osteoclasts, osteoblasts, and endothelial cells coexist and interact with each other. EVs play an important role in the communication between cells. Based on multiple functions in bone sarcoma, this review provides new ideas for the discovery of new therapeutic targets and new diagnostic analysis.

Functional interplay between long non-coding RNAs and the Wnt signaling cascade in osteosarcoma

Osteosarcoma is a common and highly malignant bone tumor among children, adolescents and young adults. However, the underlying molecular mechanisms remain largely unexplored. LncRNAs are transcripts with no or limited protein-coding capacity in human genomes, and have been demonstrated to play crucial functions in initiation, progression, therapeutic resistance, recurrence and metastasis of tumor. Considerable studies revealed a dysregulated lncRNA expression pattern in osteosarcoma, which may act as oncogenes or suppressors to regulate osteosarcoma progression. Wnt signaling pathway is an important cascade in tumorigenesis by modulation of pleiotropic biological functions including cell proliferation, apoptosis, differentiation, stemness, genetic stability and chemoresistance. Hyperactivation or deficiency of key effectors in Wnt cascade is a common event in many osteosarcoma patients. Recently, increasing evidences have suggested that lncRNAs could interplay with component of Wnt pathway, and thereby contribute to osteosarcoma onset, progression and dissemination. In this review, we briefly summarize Wnt signaling-related lncRNAs in osteosarcoma progression, aiming to gain insights into their underlying crosstalk as well as clinical application in osteosarcoma therapeutic modalities.

A minor review of microRNA-338 exploring the insights of its function in tumorigenesis

MicroRNAs(miRNAs) are small non-coding RNAs which have a critical role in various biological processes via direct binding and post-transcriptionally regulating targeted genes expression. More than one-half of human genes were regulated by miRNAs and their aberrant expression was detected in various human diseases, including cancers. miRNA-338 is a new identified miRNA and increasing evidence show that miRNA-338 participates in the progression of lots of cancers, such as lung cancer, hepatocellular cancer, breast cancer, glioma, and so on. Although a range of targets and signaling pathways such as MACC1 and Wnt/β-catenin signaling pathway were illustrated to be regulated by miRNA-338, which functions in tumor progression are still ambiguous and the underlying molecular mechanisms are also unclear. Herein, we reviewed the latest studies in miRNA-338 and summarized its roles in different type of human tumors, which might provide us new idea for further investigations and potential targeted therapy.

lncRNA‑CASC15 promotes osteosarcoma proliferation and metastasis by regulating epithelial‑mesenchymal transition via the Wnt/β‑catenin signaling pathway

Osteosarcoma (OS) is a rare type of tumor and mostly occurs in children and adolescents. Approximately 10–25% of patients with OS have lung metastases, and lung damage caused by lung metastasis is the main cause of mortality. Therefore, studying the growth and metastasis of OS is key in reducing OS mortality and improving prognosis. The expression of long non-coding RNA (lncRNA) cancer susceptibility 15 (CASC15) in OS patients or OS cell lines were quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression of vimentin, E-cadherin, N-cadherin, and cyclin D were detected by RT-qPCR and western blotting. Mice were injected with OS cell lines via the tail vein to observe tumor formation in the lung. CCK-8 and EdU assays were utilized to evaluate cell proliferation. Both Ttranswell assay and cell scratch test detected cell migration. The results revealed that lncRNA-CASC15 was highly expressed in clinical samples and OS cells. In vitro verification experiments revealed that CASC15 promoted the growth of OS cells. Rescue experiments demonstrated that CASC15 affected the cell cycle by activating the Wnt/β-catenin pathway, thereby promoting cell proliferation. Furthermore, the transfection dose test indicated that lentiviruses expressing various doses of CASC15-overexpression (oe-CASC15) altered the proliferation and migration status of OS cells. CASC15 promoted OS cell metastasis both in vivo and in vitro. The overexpression of CASC15 revealed that the occurrence of metastasis was also related to the Wnt/β-catenin pathway. The western blotting results revealed that CASC15 could lead to β-catenin entering the nucleus via the Wnt pathway to promote the epithelial-mesenchymal transition (EMT) of OS cells. To sum up, CASC15 promoted the proliferation of OS cells in vitro and the growth of OS xenograft tumors in vivo. Moreover, CASC15 promoted the entry of β-catenin into the nucleus, thus activating the Wnt pathway and subsequently promoting the EMT of OS cells.