Hsa_circ_0007031 promotes the proliferation and migration of osteosarcoma cells by sponging miR-196a-5p to regulate the HOXB6.

Circular RNAs (circRNAs), a subclass of noncoding RNAs, have been demonstrated to play an essential role in osteosarcoma (OS) development. However, there is still a significant gap in investigating its biological functions and underlying molecular mechanisms, and novel targets of circRNAs have yet to be fully explored. Herein, we found that hsa_circ_0007031 is noticeably raised in OS clinical tissues and cell lines. Hsa_circ_0007031 accelerates OS cell proliferation and migration in vitro and tumor growth and metastasis in vivo and is strongly linked with the stemness of cancer stem cells in OS. Mechanistically, hsa_circ_0007031 shares miRNA response elements with Homeobox B6 (HOXB6), which is identified as a novel pro-tumorigenic gene of OS. Hsa_circ_0007031 competitively binds to miR-196a-5p to prevent miR-196a-5p from lowering the level of HOXB6, which modulates chemokines of cytokine-cytokine receptor interaction signaling pathway and finally promotes OS malignant behavior. In summary, our data unveiled that hsa_circ_0007031/miR-196a-5p/HOXB6 axis-mediated cytokine-cytokine receptor interaction facilitates the progression of OS and maintains the properties of tumor stem cells, which could be a promising therapeutic target for OS.

Identification of Candidate MicroRNA-mRNA Subnetwork for Predicting the Osteosarcoma Progression by Bioinformatics Analysis.

Osteosarcoma (OS) is the pretty common primary cancer of the bone among the malignancies in adolescents. A single molecular component or a limited number of molecules is insufficient as a predictive biomarker of OS progression. Hence, it is necessary to find novel network biomarkers to improve the prediction and therapeutic effect for OS. Here, we identified 230 DE-miRNAs and 821 DE-mRNAs through two miRNA expression-profiling datasets and three mRNA expression-profiling datasets. We found that hsa-miR-494 is closely linked with the survival of OS patients. In addition, we analyzed GO and KEGG enrichment for targets of hsa-miR-494-5p and hsa-miR-494-3p through R programming. And five mRNAs were predicted as common targets of hsa-miR-494-5p and hsa-miR-494-3p. We further revealed that upregulated TRPS1 was strongly correlated with poor outcomes in OS patients through the survival analysis based on the TARGET database. The qRT-PCR study verified that the expression of hsa-miR-494-5p and hsa-miR-494-3p was declined considerably, while TRPS1 was notably raised in OS cells when compared to the osteoblasts. Thus, we generated a new regulatory subnetwork of key miRNAs and target mRNAs using Cytoscape software. These results indicate that the novel miRNA-mRNA subnetwork composed of hsa-miR-494-5p, hsa-miR-494-3p, and TRPS1 might be a characteristic molecule for assessing the prognostic value of OS patients.

Analysis and identification of m6A RNA methylation regulators in metastatic osteosarcoma.

Osteosarcoma (OS) is characterized by rapid growth and early metastasis. However, its mechanism remains unclear. N6-methyladenosine (m6A) modification and its regulatory factors play essential roles in most cancers, including OS. In this study, we screened out 21 m6A modifiers using the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database, followed by the identification of the critical m6A methylation modifiers. The results revealed that the expression levels of three m6A methylation regulators, namely RBM15, METTL3, and LRPPRC, were associated with the low survival rate of patients with OS. We further studied the independent prognostic factors by performing univariate and multivariate Cox analyses and found that metastasis was an independent prognostic factor for patients with OS. Furthermore, we found for the first time that RBM15 was specific for metastatic OS rather than non-metastatic OS. Moreover, the significant overexpression of RBM15 was validated in metastatic OS cell lines and in actual human clinical specimens. We also revealed that RBM15 promoted the invasion, migration, and metastasis of OS cells through loss-functional and gain-functional experiments and an animal metastatic model. In conclusion, RBM15 has a high correlation with OS metastasis formation and the decreased survival rate of patients with OS, and this may serve as a useful biomarker for predicting metastasis and prognosis of patients with OS.

Anti-inflammatory and immunomodulatory effects of the extracellular vesicles derived from human umbilical cord mesenchymal stem cells on osteoarthritis via M2 macrophages.

Osteoarthritis (OA) is a degenerative illness that greatly impacts the life quality of patients. Currently, the therapeutic approaches for OA are very limited in clinical. The extracellular vesicles (EVs) derived from different mesenchymal stem cells displayed a prominent therapeutic effect on OA. But most EVs have limited resources and the risks of host rejection, immunological response, and etc. Human umbilical cord mesenchymal stem cells (hUCMSCs) hold the advantages of easy availability, minimal immune rejection, and excellent immunomodulatory effects, although hUCMSCs-EVs have seldom been applied in OA. Herein, we investigated the potential immunomodulatory and anti-inflammatory effects of hUCMSCs-EVs on the treatment of OA. In our results, the treatment of hUCMSCs-EVs promoted the polarization of M2-type macrophages and the expression of anti-inflammation-related cytokines (IL-10). Notably, the supernate of M2 macrophages induced by hUCMSCs-EVs inhibited the level of inflammation-associated factors in OA chondrocytes caused by IL-1ß. Further, injection of hUCMSCs-EVs in the articular lumen ameliorated progression of OA and exerted chondroprotective potential based on the OA joint model created by the surgical transection of the anterior cruciate ligament (ACLT). In addition, we found five highly enriched miRNAs in hUCMSCs-EVs, including has-miR-122-5p, has-miR-148a-3p, has-miR-486-5p, has-miR-let-7a-5p, and has-miR-100-5p by High-throughput sequencing of miRNAs, with targeted genes mainly enriched in the PI3K-Akt signaling pathway. Furthermore, we also detected the protein abundance of hUCMSCs-EVs using liquidation chromatography with tandem quadrupole mass spectrometry (LC-MS/MS) analysis. Thus, our study indicates that hUCMSCs-EVs can alleviate cartilage degradation during the OA progression, mechanically may through delivering key proteins and modulating the PI3K-Akt signaling pathway mediated by miRNAs to promote polarization of M2 macrophage, exhibiting potent immunomodulatory potential. The current findings suggest that hUCMSCs-EVs might serve as a new reagent for the therapy of OA.

Prognostic Implications of the Complement Protein C1Q and Its Correlation with Immune Infiltrates in Osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is the most widespread bone tumour among childhood cancers, and distant metastasis is the dominant factor in poor prognosis for patients with OS. Therefore, it is necessary to identify new prognostic biomarkers for identifying patients with aggressive disease. METHODS: Two OS datasets (GSE21257 and GSE33383) were downloaded from the Gene Expression Omnibus (GEO) and subsequently subjected to weighted gene co-expression network analysis (WGCNA) and differential gene expression analysis (DGE) to screen candidate genes. A prognostic model was constructed using OS data derived from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) program to further screen key genes and perform gene ontology (GO) analysis. The prognostic values of key genes were assessed using the Kaplan-Meier (KM) plotter. The GEO dataset was used for immune infiltration analysis and association analysis of key genes. In addition, quantitative real-time polymerase chain reaction (qRT-PCR) was employed to validate the expression levels of potentially crucial genes in OS cell lines. RESULTS: In the present study, we found 114 genes with a highly significant correlation in the module and 44 downregulated genes; 25 candidate genes overlapped in the two parts of the genes. Among these, three key genes, C1QA, C1QB, and C1QC, were the most significant hub genes, which had the highest node degrees, were clustered into one group, and implicated in most significant biological processes (regulation of immune effector process). Moreover, these three key genes were negatively associated with the prognosis of OS and positively associated with three immune cells (follicular helper T cells, memory B cells, and CD8 T cells). Additionally, compared to non-metastatic OS cell lines, the expression of three key genes was significantly downregulated in metastatic OS cell lines. CONCLUSION: Our results revealed that three key genes (C1QA, C1QB, and C1QC) were implicated in tumour immune infiltration and may be promising biomarkers for predicting metastasis and prognosis of patients with OS.

Mechanism of cadmium poisoning on testicular injury in mice.

Cadmium is a heavy metal that is toxic to humans and the reproductive system. The present study aimed to investigate the mechanisms of cadmium-induced reproductive toxicity in a male Institute of Cancer Research mouse model of cadmium poisoning. Changes in luteinizing hormone receptor (LHR), 17α-hydroxylase and endothelial nitric oxide (NO) synthase (eNOS) expression levels were examined. A total of 24 male mice (4-week-old) were randomly divided into four groups (normal control group and low, medium and high cadmium groups) and subjected to gavage treatment with normal saline or cadmium-containing saline solutions for 8 weeks prior to sacrifice. To assess testicular injury, serum androgen levels were determined by ELISA, testicular tissue pathological changes were evaluated using hematoxylin and eosin staining. In addition, LHR, 17α-hydroxylase and eNOS expressions levels were examined by western blotting, and apoptosis was examined with a terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The results demonstrated that the severity of testes injury increased with cadmium concentration. In addition, LHR, 17α-hydroxylase and eNOS expression levels increased with low and medium concentrations of cadmium; however, they were decreased following treatment with high concentrations of cadmium. The results from the present study demonstrated that cadmium altered LHR, 17α-hydroxylase and eNOS expression levels in testicular stromal cells, which may impact testosterone synthesis. Furthermore, NO was suggested to be involved in cadmium-induced testicular injury by measurements of eNOS expression in testicular stromal cells.