Emerging landscape of circular RNAs as biomarkers and pivotal regulators in osteosarcoma.

Osteosarcoma represents the most prevailing primary bone tumor and the third most common cancer in children and adolescents worldwide. Among noncoding RNAs, circular RNAs (circRNAs) refer to a unique class in the shape of a covalently closed continuous loop with neither 5' caps nor 3'-polyadenylated tails, which are generated through back-splicing. Recently, with the development of whole-genome and transcriptome sequencing technologies, a growing number of circRNAs have been found aberrantly expressed in multiple diseases, including osteosarcoma. circRNA are capable of various biological functions including miRNA sponge, mediating alternatives, regulating genes at posttranscriptional levels, and interacting with proteins, indicating a pivotal role of circRNA in cancer initiation, progression, chemoresistance, and immune response. Moreover, circRNAs have been thrust into the spotlight as potential biomarkers and therapeutic targets in osteosarcoma. Herein, we briefly summarize the origin and biogenesis of circRNA with current knowledge of circRNA in tumorigenesis of osteosarcoma, aiming to elucidate the specific role and clinical implication of circRNAs in osteosarcoma.

Adiponectin receptor agonist AdipoRon attenuates calcification of osteoarthritis chondrocytes by promoting autophagy.

Cartilage calcification contributes to the development and progression of osteoarthritis (OA). It has been well-investigated adiponectin regulates vascular calcification. The purpose of this study is to investigate the therapeutic value and the molecular mechanism of AdipoRon, an adiponectin receptor agonist, on the chondrocytes calcification. Primary chondrocytes were isolated and cultured from normal cartilage and OA cartilage. The calcification in tissues was evaluated by inductively coupled plasma/atomic emission spectroscopy and alizarin red S staining. The calcification in chondrocytes was determined using the alkaline phosphatase (ALP) staining and an ALP assay kit. The cellular effects of AdipoRon were assessed by immunofluorescence staining and Western blot analysis. We found that calcification was significantly increased in OA cartilage tissues and cells. Importantly, the degree of calcification and ALP activity of the OA chondrocytes was decreased upon the treatment with AdipoRon. The AdipoRon-induced cellular effects, including the reduction of the calcification of chondrocytes and improvement of autophagy, were blocked by dorsomorphin, an 5'-adenosine monophosphate-activated protein kinase (AMPK) inhibitor. Moreover, autophagy activation by AdipoRon was mediated by the AMPK-mammalian target of rapamycin (mTOR) signaling pathway. Our results suggest that AdipoRon significantly alleviates the calcification of OA chondrocytes via activating AMPK-mTOR signaling to promote autophagy. Therefore, AdipoRon could be a potential therapeutic agent for the prevention and treatment of OA.

The predictive value of lncRNA MIR31HG expression on clinical outcomes in patients with solid malignant tumors.

BACKGROUND: Emerging studies have explored the prognostic value of MIR31HG in cancers, but its role remains elusive. Herein, we aimed to summarize the prognostic potential of MIR31HG in this study. METHODS: Several databases were searched for literature retrieval on Dec 5, 2019. Overall and subgroup analyses were conducted to measure the relationship between MIR31HG expression and clinical outcomes. Moreover, GEPIA was applied for validation of prognostic value of MIR31HG in tumor patients in TCGA dataset. RESULTS: Overall, seventeen studies with 2573 patients were enrolled. Compared to counterparts, those patients with high MIR31HG expression tended to have shorter RFS. Notably, MIR31HG overexpression predicted unfavorable OS in lung cancer. By contrast, gastrointestinal cancer patients with elevated MIR31HG expression predicted better OS and disease-free survival. Additionally, MIR31HG overexpression was significantly associated with worse clinicopathological features including advanced tumor stage and LNM in lung cancer, but favorable clinical characteristics in gastrointestinal cancer. Moreover, the positive association between MIR31HG and OS in lung cancer was further confirmed in TCGA dataset. CONCLUSION: Overexpression of MIR31HG suggested remarkable association with poor prognosis in terms of OS, tumor stage, and LNM in lung cancer, but favorable prognosis in gastrointestinal cancer. Therefore, MIR31HG may serve as a promising prognostic biomarker in multiple cancers.

A Novel 3D-Printed Device for Precise Percutaneous Placement of Cannulated Compression Screws in Human Femoral Neck Fractures.

BACKGROUND: The aim of this study was to investigate the application of computer-aided design and 3D printing technology for percutaneous fixation of femoral neck fractures using cannulated compression screws. METHODS: Using computed tomography data, an individualized proximal femur model was created with a 3D printer. The reduction of the femoral neck fracture and the placement of the cannulated compression screws were simulated on a computer. A 3D printing guide plate was designed to match the proximal femur. After demonstrating the feasibility of the 3D model before the surgical procedure, the guide needles and cannulated compression screws were inserted with the aid of the 3D-printed guide plate. RESULTS: During the procedure, the 3D-printed guide plate for each patient matched the bone markers of the proximal femur. With the aid of the 3D-printed guide plate, three cannulated compression screws were accurately inserted into the femoral neck to treat femoral neck fractures. After screw placement, intraoperative X-ray examination showed results that were consistent with the preoperative design. The time taken to complete the procedure in the guide plate group was 35.3 ± 2.1 min, the intraoperative blood loss was 6.3 ± 2.8 mL, and X-ray fluoroscopy was only performed 9.1 ± 3.5 times. Postoperative radiographs showed adequate reduction of the femoral neck fractures. The entry point, entry direction, and length of the three cannulated compression screws were consistent with the preoperative design, and the screws did not penetrate the bone cortex. CONCLUSION: Using computer-aided design and 3D printing technology, personalized and accurate placement of cannulated compression screws can be realized for the treatment of femoral neck fractures. This technique can shorten the time required for the procedure and reduce damage to the femoral neck cortex, intraoperative bleeding, and the exposure of patients and healthcare staff to radiation.

Exosomal miR-500 Derived From Lipopolysaccharide-Treated Macrophage Accelerates Liver Fibrosis by Suppressing MFN2.

Liver fibrosis is an outcome of chronic hepatic injury, which can eventually result in cirrhosis, liver failure, and even liver cancer. The activation of hepatic stellate cell (HSC) is a prominent driver of liver fibrosis. Recently, it has been found that the crosstalk between HSCs and immune cells, including hepatic macrophages, plays an important role in the initiation and development of liver fibrosis. As a vital vehicle of intercellular communication, exosomes transfer specific cargos into HSCs from macrophages. Here, we show that exosomes derived from lipopolysaccharide (LPS)-treated macrophages has higher expression level of miR-500. And overexpression or inhibition of miR-500 in macrophage exosomes could promote or suppress HSC proliferation and activation. Treatment of exosomes with miR-500 overexpression can accelerate liver fibrosis in CCl4-induced liver fibrosis mouse model. miR-500 promotes HSC activation and liver fibrosis via suppressing MFN2. Moreover, miR-500 in serum exosomes could be a biomarker for liver fibrosis. Taken together, exosomal miR-500 derived from LPS-activated macrophages promotes HSC proliferation and activation by targeting MFN2 in liver fibrosis.

Circ_0134111 knockdown relieves IL-1ß-induced apoptosis, inflammation and extracellular matrix degradation in human chondrocytes through the circ_0134111-miR-515-5p-SOCS1 network.

BACKGROUND: Osteoarthritis (OA) is characterized by chondrocyte injury and dysfunction, such as excessive apoptosis, inflammatory response and extracellular matrix (ECM) degradation. Circular RNA (circRNA) deregulation is reported to be involved in OA. Our study aimed to explore the role of circ_0134111 in OA. METHODS: Human chondrocytes were treated with interleukin-1ß (IL-1ß) to mimic OA cell model. The expression of circ_0134111, miR-515-5p and suppressor of cytokine signaling 1 (SOCS1) mRNA was measured by real-time quantitative polymerase chain reaction (RT-qPCR), and the protein levels of SOCS1 and apoptosis-/inflammation-/ECM-related markers were determined by western blot. Cell proliferation and cell apoptosis were assessed using cell counting kit-8 (CCK-8) and flow cytometry assay, respectively. For mechanism analysis, the predicted interaction between miR-515-5p and circ_0134111 or SOCS1 was verified by dual-luciferase reporter assay, pull-down assay and RNA immunoprecipitation (RIP) assay. Rescue experiments were performed to explore the interplay between miR-515-5p and circ_0134111 or SOCS1. RESULTS: Circ_0134111 was overexpressed in OA cartilage tissues and IL-1ß-induced chondrocytes. IL-1ß-induced chondrocyte apoptosis, inflammatory responses and ECM degradation were alleviated by circ_0134111 knockdown or miR-515-5p restoration. Circ_0134111 acted as miR-515-5p sponge to regulate miR-515-5p expression, and miR-515-5p deficiency reversed the effects of circ_0134111 knockdown in IL-1ß-induced chondrocytes. MiR-515-5p directly bound to SOCS1, and circ_0134111 decoyed miR-515-5p to increase SOCS1 level. MiR-515-5p restoration alleviated IL-1ß-induced chondrocyte apoptosis, inflammatory responses and ECM degradation, While SOCS1 overexpression partly abolished these effects. CONCLUSION: Circ_0134111 knockdown alleviated apoptosis, inflammatory responses and ECM degradation in OA cell model by mediating the miR-515-5p-SOCS1 network, hinting that circ_0134111 was involved in OA progression.

Intercalary Allograft to Reconstruct Large-Segment Diaphysis Defects After Resection of Lower Extremity Malignant Bone Tumor.

AIM: To evaluate the clinical effect of intercalary allograft transplantation and reconstruction in the treatment of diaphyseal defect after resection of lower extremity malignant bone tumor. METHODS: Clinical data of 17 patients diagnosed with malignant lower-limb bone tumors and having undergone segmental allograft reconstruction with a mean follow-up of 49.8 (26-78) months were included. Segmental allografts of average 17-cm length preserved by deep-freezing were used and fixed using intramedullary nail, double plate, and intramedullary nail and plate combination in 2, 5, and 10 patients, respectively. Host-donor junctions were perfectly and roughly matched in 5 and 12 patients, respectively. Allograft union, local recurrence, and complications were assessed using clinical and radiological tests. Allograft union was evaluated using the International Society of Limb Salvage (ISOLS) scoring system. The functional prognosis was evaluated using the Musculoskeletal Tumour Society (MSTS) scoring system. RESULTS: Intercalary allograft reconstruction of femoral shaft, tibial shaft, and distal tibia with ankle arthrodesis was performed in eight, four, and five patients, respectively. Two patients had local recurrence and underwent amputation; one died of metastasis. Host-donor junctions in two patients showed nonunion; 12 patients achieved bone union. The average union time was 12.1 months. No allograft fracture or infection occurred. Union rates were 100% and 88.2% at metaphyseal and diaphyseal junctions, respectively. Healing time differed significantly between the precisely and roughly matched groups (p<0.01). The incidence of nonunion was higher after intramedullary nailing than after the other two methods (p<0.05). The mean MSTS score was 24.2 (14-29) at the end of follow-up. CONCLUSION: Intercalary allograft transplantation is an effective strategy for diaphyseal defect following post-tumor resection in the lower extremity. Good bone healing after allograft reconstruction is achieved with stable internal fixation and perfectly matched host-donor interfaces.

Identification of a potential gene target for osteoarthritis based on bioinformatics analyses.

BACKGROUND: Osteoarthritis (OA) is the most common chronic joint disease worldwide. It is characterized by pain and limited mobility in the affected joints and may even cause disability. Effective clinical options for its prevention and treatment are still unavailable. This study aimed to identify differences in gene signatures between tissue samples from OA and normal knee joints and to explore potential gene targets for OA. METHODS: Five gene datasets, namely GSE55457, GSE55235, GSE12021, GSE10575, and GSE1919, were selected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using the R programming software. The functions of these DEGs were analyzed, and a protein-protein interaction (PPI) network was constructed. Subsequently, the most relevant biomarker genes were screened using a receiver operating characteristic (ROC) curve analysis. Finally, the expression of the protein encoded by the core gene PTHLH was evaluated in clinical samples. RESULTS: Eleven upregulated and 9 downregulated DEGs were shared between the five gene expression datasets. Based on the PPI network and the ROC curves of upregulated genes, PTHLH was identified as the most relevant gene for OA and was selected for further validation. Immunohistochemistry confirmed significantly higher PTHLH expression in OA tissues than in normal tissues. Moreover, similar PTHLH levels were detected in the plasma and knee synovial fluid of OA patients. CONCLUSION: The bioinformatics analysis and preliminary experimental verification performed in this study identified PTHLH as a potential target for the treatment of OA.

Prognostic and clinicopathologic significance of long non-coding RNA opa-interacting protein 5-antisense RNA 1 in multiple human cancers.

Background: OIP5-AS1 has been reported to be aberrantly expressed in multiple cancers and associated with clinical outcomes. We conducted this study to assess the generalized prognostic value of OIP5-AS1 in cancers.Methods: PubMed, Web of science, and Cochrane Library were searched for eligible studies. Hazards ratios (HRs) or odd ratios (ORs) with 95% confidence intervals (CIs) were pooled to estimate the prognostic value of OIP5-AS1 in cancers, including overall survival (OS), age, gender, tumor size, clinical stage, and lymph node metastasis (LNM). Publication bias was measured by Begg's test and funnel plot. Sensitivity analysis were used to detect the stability of pooled results.Results: Overall, eleven studies containing 713 patients were eventually enrolled. The pooled results showed that high OIP5-AS1 expression was correlated with shorter OS (HR = 0.48, 95%CI: 0.35-0.64), regardless of the sample size, tumor type and follow-up time. Furthermore, elevated expression of OIP5-AS1 indicated advanced clinical stage (OR = 2.12, 95% CI: 1.06-4.23), but not associated with age, gender, tumor size and LNM. No publication bias was detected.Conclusion: High expression of lncRNA OIP5-AS1 may predict a poor OS and advanced clinical stage, implicating that OIP5-AS1 may be a possible prognostic factor in cancers.

Target-activated transcription for the amplified sensing of protease biomarkers.

Signal amplification is an effective way to achieve sensitive analysis of biomarkers, exhibiting great promise in biomedical research and clinical diagnosis. Inspired by the transcription process, here we present a versatile strategy that enables effective amplification of proteolysis into nucleic acid signal outputs in a homogeneous system. In this strategy, a protease-activatable T7 RNA polymerase is engineered as the signal amplifier and achieves 3 orders of magnitude amplification in signal gain. The versatility of this strategy has been demonstrated by the development of sensitive and selective assays for protease biomarkers, such as matrix metalloproteinase-2 (MMP-2) and thrombin, with sub-picomole sensitivity, which is 4.3 × 103-fold lower than that of the standard peptide-based method. Moreover, the proposed assay has been further applied in the detection of MMP-2 secreted by cancer cells, as well as in the assessment of MMP-2 levels in osteosarcoma tissue samples, providing a general approach for the monitoring of protease biomarkers in clinical diagnosis.

FGF-induced LHX9 regulates the progression and metastasis of osteosarcoma via FRS2/TGF-ß/ß-catenin pathway.

BACKGROUND: Fibroblast growth factor (FGF) and tumor growth factor-ß (TGFß) have emerged as pivotal regulators during the progression of osteosarcoma (OS). LHX9 is one crucial transcription factor controlled by FGF, however, its function in OS has not been investigated yet. METHODS: The expression of LHX9, FRS2, BMP4, TGF-beta R1, SMAD2, beta-catenin and metastasis-related proteins was measured by real-time quantitative PCR (RT-qPCR) and Western blot. CCK-8 assay and colony formation assay were employed to determine the proliferation of OS cells, while scratch wound healing assay and transwell assay were used to evaluate their migration and invasion, respectively. In vivo tumor growth and metastasis were determined by subcutaneous or intravenous injection of OS cells into nude mice. RESULTS: LHX9 expression was evidently up-regulated in OS tumor tissues and cell lines. Knockdown of LHX9 impaired the proliferation, migration, invasion and metastasis of OS cells. Mechanistically, LHX9 silencing led to the down-regulation of BMP-4, ß-catenin and metastasis-related proteins, which was also observed in beta-catenin knockdown OS cells. By contrast, FRS2 knockdown conduced to the up-regulation of LHX9, BMP4, ß-catenin and TGF-ßR1, while TGF-beta inhibition repressed the expression of LHX9 and metastasis-related proteins. Additionally, let-7c modulates LHX9 and metastasis-related proteins by suppressing TGF-beta R1 expression on transcriptional level. CONCLUSIONS: This study revealed LHX9 was essential for the proliferation, migration, invasion, and metastasis of OS cells via FGF and TGF-ß/ß-catenin signaling pathways.

MicroRNA-15a-5p Regulates the Development of Osteoarthritis by Targeting PTHrP in Chondrocytes.

BACKGROUND AND AIMS: A growing body of research has demonstrated that the degeneration of chondrocytes is the primary cause of osteoarthritis (OA). Parathyroid hormone-related protein (PTHrP) can alleviate the degeneration of chondrocytes via promotion of chondrocyte proliferation and inhibition of terminal differentiation, but the underlying mechanism remains unknown. This study aimed to identify the microRNAs (miRNAs) that may target PTHrP and regulate the proliferation and terminal differentiation of chondrocytes. METHODS: Bioinformatic analysis was used to predict which miRNAs target PTHrP. We collected human knee cartilage specimens to acquire the primary chondrocytes, which we then used to test the expression and function of the targeted miRNAs. To explore the effects of miR-15a-5p on the putative binding sites, specific mimics or inhibitors were transfected into the chondrocytes. Furthermore, a dual-luciferase reporter gene assay and chondrocyte degeneration-related factors were used to verify the possible mechanism. RESULTS: The expression of PTHrP was upregulated in the OA chondrocytes, whilst miR-15a-5p was downregulated in the OA chondrocytes. A negative correlation was observed between PTHrP and miR-15a-5p. The knockdown of miR-15a-5p promoted the growth of chondrocytes and inhibited calcium deposition, whilst overexpression of miR-15a-5p reversed this trend. The effect of miR-15a-5p overexpression was neutralised by PTHrP. Dual-luciferase reporter assays revealed that PTHrP can be used as a novel targeting molecule for miR-15a-5p. CONCLUSIONS: miR-15a-5p promotes the degeneration of chondrocytes by targeting PTHrP and, in addition to helping us understand the development of OA, may be a potential biomarker of OA.

Expression of epidermal growth factor-like domain 7 correlates with clinicopathological features of osteosarcoma.

Epidermal growth factor-like domain 7 gene (EGFL7) encodes an angiogenesis related factor and plays a crucial role in many human cancers. Previous studies have suggestedthat EGFL7 acts as a facilitator for tumor angiogenesis. However, little is known as to its role in osteosarcoma. Our aim was to investigate the expression of EGFL7 and to explore its correlation with the clinicopathological features of osteosarcoma. Tumor tissues from 32 Chinese young patients (below age of 24) with osteosarcoma were collected and subjected to EGFL7 detection by immunohistochemistry. The tissues from 10 patients with osteochondroma were collected and analyzed as controls. The intratumoral microvessel density (MVD) was examined by immunohistochemical staining using CD34 antibody. The results showed that patients with osteosarcoma had higher levels of EGFL7 in the tumor tissues compared to patients with osteochondroma (p<0.001). The expression of EGFL7 was significantly higher in advanced osteosarcoma (Enneking IIB-III) than that in early tumor stage (Enneking IA-IIA) (p<0.01). There is also a significant correlation between increased expression of EGFL7 and the Enneking stage (R = 0.714, p<0.001). Moreover, we detected a higher level of EGFL7 expression in tumor tissues of patients with recurrent or metastatic (bone or lung) osteosarcoma than those without recurrence or metastasis after 3 years' follow-up (p<0.01). There is no detectable difference of EGFL7 expression between tumor tissues from different tumor location and sex. Finally, we showed that high level of EGFL7expression was significantly correlated with high MVD (R = 0.829, p<0.001). In conclusion, our study demonstrates for the first time that there was a tumor grade-dependent up-regulation of EGFL7 in osteosarcoma. Elevated EGFL7 expression correlated with poor clinical outcome: i.e. advanced tumor stage, recurrent and metastatic osteosarcoma. Our findings support EGFL7 as a potential prognostic marker, and may provide novel insights for the diagnostics and therapeutics of osteosarcoma.