Role of TKI for Metastatic Osteogenic Sarcoma

CT-derived Radiomics Predicts the Efficacy of Tyrosine Kinase Inhibitors in Osteosarcoma Patients with Pulmonary Metastasis

BACKGROUND

To construct and validate the CT-based radiomics model for predicting the tyrosine kinase inhibitors (TKIs) effects in osteosarcoma (OS) patients with pulmonary metastasis.

METHODS

OS patients with pulmonary metastasis treated with TKIs were randomly separated into training and testing cohorts (2:1 ratio). Radiomic features were extracted from the baseline unenhanced chest CT images. The random survival forest (RSF) and Kaplan-Meier survival analyses were performed to construct and evaluate radiomics signatures (R-model-derived). The univariant and multivariant Cox regression analyses were conducted to establish clinical (C-model) and combined models (RC-model). The discrimination abilities, goodness of fit and clinical benefits of the three models were assessed and validated in both training and testing cohorts.

RESULTS

A total of 90 patients, 57 men and 33 women, with a mean age of 18 years and median progression-free survival (PFS) of 7.2 months, were enrolled. The R-model was developed with nine radiomic features and demonstrated significant predictive and prognostic values. In both training and testing cohorts, the time-dependent area under the receiver operating characteristic curves (AUC) of the R-model and RC-model exhibited obvious superiority over C-model. The calibration and decision curve analysis (DCA) curves indicated that the accuracy of the R-model was comparable to RC-model, which exhibited significantly better performance than C-model.

CONCLUSIONS

The R-model showed promising potential as a predictor for TKI responses in OS patients with pulmonary metastasis. It can potentially identify pulmonary metastatic OS patients most likely to benefit from TKIs treatment and help guide optimized clinical decisions.

Construction of molecular subtype model of osteosarcoma based on endoplasmic reticulum stress and tumor metastasis-related genes

Introduction

Osteosarcoma, the prevailing primary bone malignancy among children and adolescents, is frequently associated with treatment failure primarily due to its pronounced metastatic nature.

Methods

This study aimed to establish potential associations between hub genes and subtypes for the treatment of metastatic osteosarcoma. Differentially expressed genes were extracted from patients diagnosed with metastatic osteosarcoma and a control group of non-metastatic patients, using the publicly available gene expression profile (GSE21257). The intersection of these gene sets was determined by focusing on endoplasmic reticulum (ER) stress-related genes sourced from the GeneCards database. We conducted various analytical techniques, including functional and pathway enrichment analysis, WGCNA analysis, protein-protein interaction (PPI) network construction, and assessment of immune cell infiltration, using the intersecting genes. Through this analysis, we identified potential hub genes.

Results

Osteosarcoma subtype models were developed using molecular consensus clustering analysis, followed by an examination of the associations between each subtype and hub genes. A total of 138 potential differentially expressed genes related to endoplasmic reticulum (ER) stress were identified. These genes were further investigated using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) pathways. Additionally, the PPI interaction network revealed 38 interaction relationships among the top ten hub genes. The findings of the analysis revealed a strong correlation between the extent of immune cell infiltration and both osteosarcoma metastasis and the expression of hub genes. Notably, the differential expression of the top ten hub genes was observed in osteosarcoma clusters 1 and 4, signifying their significant association with the disease.

Conclusion

The identification of ten key genes linked to osteosarcoma metastasis and endoplasmic reticulum stress bears potential clinical significance. Additionally, exploring the molecular subtype of osteosarcoma has the capacity to guide clinical treatment decisions, necessitating further investigations and subsequent clinical validations.

Does primary tumor resection improve survival for patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at diagnosis ?

BACKGROUND

Recent studies demonstrated that primary tumor resection (PTR) improves survival of patients with metastatic bone sarcomas. However, it remains quite unclear regarding the role of PTR in the treatment of sarcomas of pelvic bones with synchronous metastasis at diagnosis.

METHODS

Using the Surveillance, Epidemiology, and End Results Program, we enrolled a total of 385 patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at initial diagnosis, including 139 patients with osteosarcoma, 176 with Ewing sarcoma, and 70 with chondrosarcoma. Association between PTR and disease-specific survival (DSS) were investigated using the univariable and multivariable Cox regression models. Hazard ratio (HR) and 95% confidence interval (CI) were reported. Representative institutional PTR strategies and clinical outcomes for patients with metastatic pelvic sarcomas from our cancer center were displayed.

RESULTS

The usage rate of PTR was 28.1% (39/139) in osteosarcoma, 13.6% (24/176) in Ewing sarcoma, and 41.4% (29/70) in chondrosarcoma with synchronous metastatic lesions. PTR was not associated with an improved DSS for metastatic pelvic osteosarcoma (HR = 0.686, 95% CI = 0.430 ~ 1.094, P = 0.113) and Ewing sarcoma (HR = 0.580, 95% CI = 0.291 ~ 1.154, P = 0.121). The use of PTR was associated with an improved DSS for metastatic pelvic chondrosarcoma (HR = 0.464, 95% CI = 0.225 ~ 0.954, P = 0.037).

CONCLUSION

Primary lesion resection may provide a survival benefit for metastatic chondrosarcoma, but not for osteosarcoma and Ewing sarcoma of pelvic bones, sacrum, and coccyx. This population-based study recommends an active surgical intervention for metastatic chondrosarcoma while non-surgical treatment for metastatic osteosarcoma and Ewing sarcoma of the pelvis in terms of survival improvement.

Construction of a prognostic risk score model based on the ARHGAP family to predict the survival of osteosarcoma

BACKGROUND

Osteosarcoma (OS) is the most common primary malignancy of bone tumors. More and more ARHGAP family genes have been confirmed are to the occurrence, development, and invasion of tumors. However, its significance in osteosarcoma remains unclear. In this study, we aimed to identify the relationship between ARHGAP family genes and prognosis in patients with OS.

METHODS

OS samples were retrieved from the TCGA and GEO databases. We then performed LASSO regression analysis and multivariate COX regression analysis to select ARHGAP family genes to construct a risk prognosis model. We then validated this prognostic model. We utilized ESTIMATE and CIBERSORT algorithms to calculate the stroma and immune scores of samples, as well as the proportions of tumor infiltrating immune cells (TICs). Finally, we conducted in vivo and in vitro experiments to investigate the effect of ARHGAP28 on osteosarcoma.

RESULTS

We selected five genes to construct a risk prognosis model. Patients were divided into high- and low-risk groups and the survival time of the high-risk group was lower than that of the low-risk group. The high-risk group in the prognosis model constructed had relatively poor immune function. GSEA and ssGSEA showed that the low-risk group had abundant immune pathway infiltration. The overexpression of ARHGAP28 can inhibit the proliferation, migration, and invasion of osteosarcoma cells and tumor growth in mice, and IHC showed that overexpression of ARHGAP28 could inhibit the proliferation of tumor cells.

CONCLUSION

We constructed a risk prognostic model based on five ARHGAP family genes, which can predict the overall survival of patients with osteosarcoma, to better assist us in clinical decision-making and individualized treatment.

Current progress and open challenges for applying tyrosine kinase inhibitors in osteosarcoma

Osteosarcoma (OS) is a mesenchymal-origin tumor that constitutes the most common primary malignant bone tumor. The survival rate of the patients has significantly improved since the introduction of neoadjuvant chemotherapy and extensive resection, but it has stagnated in recent 40 years. Tyrosine kinase inhibitors (TKIs) have played a key part in the treatment of malignant tumors. In advanced OS, TKIs including anlotinib, apatinib, sorafenib, etc. have significantly improved the progression-free survival of patients, while the overall survival remains unchanged. The main reason is the rapid and inevitable progress of acquired drug resistance of OS. However, as the application of TKIs in OS and other tumors is still in the exploratory phase, its drug resistance mechanism and corresponding solutions are rarely reported. Hence, in this review, we summarize knowledge of the applications of TKIs, the mechanism of TKIs resistance, and the attempts to overcome TKIs resistance in OS, which are the three potentially novel insights of TKIs in OS. Because most evidence is derived from studies using animal and cell models, we also reviewed clinical trials and related bioinformatics data available in public databases, which partially improved our understanding of TKIs applications.

The Combination of Anlotinib and Gemcitabine/Docetaxel in Patients with Metastatic Osteosarcoma Who Have Failed Standard Chemotherapy

Purpose

The options for the second-line treatment of metastatic osteosarcoma are still limited. Anlotinib is a multi-kinase inhibitor which has shown promising efficacy and good tolerability in various cancer types. This retrospective study was conducted to evaluate the efficacy and safety of anlotinib combined with gemcitabine/docetaxel (GD) in patients with metastatic osteosarcoma who have failed first-line chemotherapy.

Patients and Methods

The data of patients who received anlotinib combined with GD or GD were collected. The primary endpoint was progression-free survival. Secondary endpoints included objective response rate and safety.

Results

From July 2013 to November 2020, a total of 32 patients were enrolled, 13 received anlotinib combined with GD and 19 received GD. Median PFS was 9.0 months (95% CI 6.7-39.1) in the combination group and 5.0 months (95% CI 1.2-6.7) in the chemotherapy group. ORR were 38.4% and 15.8%, DCR were 69.2% and 38.1% in the combination and chemotherapy group, respectively. The most common adverse events included fatigue (78.9% in the combination group vs 69.2% in the chemotherapy group), hypertension (46.2% vs 10.5%), diarrhea (38.5% vs 21.1%), hypothyroidism (38.5% vs 15.8%), neutropenia (23.1% vs 36.8%) and AST elevation (30.8% vs 21.1%). The most common grade 3 or worse adverse events included hand-foot reaction (7.7% vs 5.3%), hypothyroidism (15.4% vs 0), neutropenia (0 vs 10.5%).

Conclusion

The combination of anlotinib and GD showed favorable efficacy with manageable toxicities compared with GD in the second-line treatment for metastatic osteosarcoma. This combination therapy deserves further investigations in patients with osteosarcoma.

MiR-659-3p inhibits osteosarcoma progression and metastasis by inhibiting cell proliferation and invasion via targeting SRPK1

OBJECTIVE

Osteosarcoma is the most common primary bone cancer that affects mostly children and young adults. Despite the advances in osteosarcoma treatment, the long-term survival rate of metastatic patients has not significantly improved in the past few decades, thus demonstrating the need for novel therapeutic targets or methods to improve metastatic osteosarcoma treatment. In this study we aimed to elucidate the role of miR-659-3p and SRPK1 in osteosarcoma.

METHODS

We evaluated miR-659-3p and SRPK1 function in osteosarcoma cell proliferation, migration, and cell cycle progression in vitro by using gain- and loss-of-function strategies. The effect of miR-659-3p in tumor progression and metastasis was determined by in vivo mouse model.

RESULTS

We revealed that expression of miR-659-3p was significantly downregulated in osteosarcoma compared with normal bone cells and was inversely correlated with serine-arginine protein kinase 1 (SRPK1) expression. We proved that miR-659-3p targets 3' UTR of SRPK1 and negatively regulates SRPK1 expression in osteosarcoma cells via luciferase assay. In vitro studies revealed that gain of miR-659-3p function inhibited osteosarcoma cells growth, migration, and invasion by down-regulating SRPK1 expression. Inversely, inhibiting miR-659-3p in osteosarcoma cells promoted cell growth, migration, and invasion. Cell cycle profile analysis revealed that miR-659-3p inhibited osteosarcoma cells' G1/G0 phase exit by down-regulating SRPK1 expression. By using an in vivo mouse model, we demonstrated that miR-659-3p inhibits osteosarcoma tumor progression and lung metastasis by inhibiting SRPK1 expression and potentially downstream cell proliferation, and epithelial-to-mesenchymal transition genes.

CONCLUSIONS

This study demonstrated that miR-659-3p is a potential therapeutic method and SRPK1 is a potential therapeutic target for osteosarcoma treatment.

Long-Term Efficacy and Safety of Anlotinib as a Monotherapy and Combined Therapy for Advanced Sarcoma

Objective

To analyze the effectiveness of the long-term (> 12 months) administration of anlotinib as a monotherapy or combined therapy in patients with advanced sarcomas.

Methods

A retrospective analysis was conducted of patients with advanced sarcomas with measurable target lesions since 2018. Twenty-two of the patients had taken anlotinib regularly for > 12 months. The patients’ general information and the drug’s clinical efficacy and toxicity data were collected and statistically analyzed using RECIST 1.1 to measure the target lesions and tumor PFS time as the main endpoints. We used a swimmer plot to observe the drug’s efficacy and duration, and employed a waterfall plot to express the best treatment effect.

Results

The study included 14 male and 8 female patients, ranging in age from 14 to 75 (mean: 44.82) years. The primary diseases included alveolar soft part sarcoma, synovial sarcoma, leiomyosarcoma, and others. The metastasis sites were the lungs in fifteen cases, lymph nodes in four cases, and multiple sites in three cases. Fourteen patients had previously undergone chemotherapy. The current therapy protocol was oral anlotinib alone for nine cases, combination chemotherapy for nine cases, and combination immunotherapy (anti-PD-1) for four cases. The highest clinical efficacy was complete remission (CR) in four (18.18%) cases, partial response (PR) in five (22.73%) cases, and stable disease in 13 (59.09%) cases, with an odds ratio of response of 40.91%. The mean PFS for the CR, PR, and stable disease groups was 16.50, 14.50, and 29.31 months, respectively (p < 0.05). The main adverse effects included hand-foot syndrome, hypertension, and leukopenia.

Conclusion

Anlotinib monotherapy or combination therapy can be more effective and safer for certain advanced sarcomas, with more extended maintenance and acceptable side effects. Clinical efficacy at the CR and PR levels might predict the long-term PFS in certain advanced sarcomas.

Dissecting the effect of sphingolipid metabolism gene in progression and microenvironment of osteosarcoma to develop a prognostic signature

Sphingolipid metabolism (SM) fuels tumorigenesis and the malignant progression of osteosarcoma (OS), which leads to an unfavorable prognosis. Elucidating the molecular mechanisms underlying SM in osteosarcoma and developing a SM-based prognostic signature could be beneficial in the clinical setting. This study included 88 frozen OS samples to recognize the vital SM-relevant genes in the development of OS utilizing univariate Cox regression. The Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was conducted on the SM- relevant genes to minimize the risk of overfitting. The prognostic signature was generate utilizing the multivariable Cox regression analysis and was verified in the validation cohort. Moreover, cellular and molecular mechanisms associated with SM have an unfavorable prognosis for OS patients and have been widely studied. Resultantly, an SM-based prognostic risk model was established according to critical prognostic genes (CBS, GLB1, and HACD1), which had an excellent ability to predict the prognosis of OS patients (AUC for the train cohort was 0.887 and AUC for validation cohort was 0.737). The high-risk OS patients identified based on this prognostic signature had significantly poor immune microenvironment, indicated by significantly low immune score (mean=216.290 ± 662.463), reduced infiltrations of 25 immune cells, including NK cells (LogFC= -0.3597), CD8+T cells ((LogFC=-0.2346), Cytolytic activity ((LogFC=-0.1998), etc. The immunosuppressive microenvironment could be due to dysregulated SM of glycolipids. Further, a nomogram was constructed by integrating the SM-based prognostic signature and clinical paraments to facilitate clinical application. The nomogram could accurately predict the prognosis of OS invalids. Collectively, this study clarified the function of SM in the development of OS and helped develop a tool for risk stratification based on SM-related genes with application in clinical settings. The results of our study will aid in identifying high-risk patients and provide individualized treatments.

A novel small-molecule antagonist enhances the sensitivity of osteosarcoma to cabozantinib in vitro and in vivo by targeting DNMT-1 correlated with disease severity in human patients

Advanced osteosarcoma (OSA) is highly aggressive and can lead to distant metastasis or recurrence. Here, a novel small-molecule inhibitor/antagonist of DNA methyltransferase 1 (DNMT-1) named DI-1 (inhibitor of DNMT-1) was explored to enhance the antitumor effect of a molecular-targeted agent, cabozantinib, on OSA cell lines. In patients with OSA, expression of DNMT-1 was negatively related with that of microRNA (miR)-34a and associated with a poor prognosis. In OSA cell lines (OSA cell line U2OS and an OSA cell line U2OSR resistance to cabozantinib), DI-1 treatment enhanced miR-34a expression by inhibiting hypermethylation of the promoter region of miR-34a mediated by DNMT-1. DI-1 enhanced the sensitivity of OSA cells (U2OS, 143B and MG63) to cabozantinib and other molecular-targeted agents by enhancing miR-34a expression and repressing activation of the Notch pathway. Mechanistically, DI-1 repressed recruitment of DNMT-1 to the promoter region of miR-34a and, in turn, decreased the methylation rate in the promoter region of miR-34a in OSA cells. These results suggest that repressing DNMT-1 activation by DI-1 enhances miR-34a expression in OSA cells and could be a promising therapeutic strategy for OSA.

Avenues of research in dietary interventions to target tumor metabolism in osteosarcoma

Osteosarcoma (OS) is the most frequent primary bone cancer, affecting mostly children and adolescents. Although much progress has been made throughout the years towards treating primary OS, the 5-year survival rate for metastatic OS has remained at only 20% for the last 30 years. Therefore, more efficient treatments are needed. Recent studies have shown that tumor metabolism displays a unique behavior, and plays important roles in tumor growth and metastasis, making it an attractive potential target for novel therapies. While normal cells typically fuel the oxidative phosphorylation (OXPHOS) pathway with the products of glycolysis, cancer cells acquire a plastic metabolism, uncoupling these two pathways. This allows them to obtain building blocks for proliferation from glycolytic intermediates and ATP from OXPHOS. One way to target the metabolism of cancer cells is through dietary interventions. However, while some diets have shown anticancer effects against certain tumor types in preclinical studies, as of yet none have been tested to treat OS. Here we review the features of tumor metabolism, in general and about OS, and propose avenues of research in dietary intervention, discussing strategies that could potentially be effective to target OS metabolism.

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.

iNOS Promotes the Development of Osteosarcoma via Wnt/β-Catenin Pathway

Inducible nitric oxide synthase (iNOS), accompanied with protumor and antitumor activity, has been studied in multiple cancers. However, the role of iNOS expression in osteosarcoma (OS) is far from being fully understood. In present work, iNOS levels were detected in OS tissues and cell lines. Colony formation assay, Transwell assay, and fow cytometer were used to assess proliferation, migration, invasion, and apoptosis abilities in vitro after iNOS inhibition. Western blotting determined the expressions of iNOS, MMP2, MMP9, C-MYC, Ki67, PCNA, and β-catenin. Mice transfected with OS cells were to evaluate tumor formation. IHC assay was to evaluate the expressions of iNOS and β-catenin in mice. The results showed that iNOS was upregulated in both OS tissues and cells compared with that in matched normal tissues or cells. And we found that proliferation, migration, and invasion numbers of OS cells were decreased, and apoptosis numbers of OS cells were increased after iNOS inhibition. MMP2, MMP9, C-MYC, Ki67, and PCNA levels were also reduced in OS cells treated with iNOS inhibition. Else, iNOS inhibition would suppress β-catenin expression in OS cells to regulate MMP2, MMP9, C-MYC, Ki67, and PCNA expressions. In addition, tumor formation, iNOS expression, and β-catenin expression were inhibited in mice transplanted with iNOS knockout OS cells. These results indicated that iNOS might be a potential therapeutic target for OS.

Receptor tyrosine kinase inhibitors for the treatment of osteosarcoma and Ewing sarcoma

Adjuvant chemotherapy for osteosarcoma and Ewing sarcoma consists of conventional cytotoxic regimens that have changed little over the past decades. There is an urgent need for agents that are more effective and have less long-term toxicity. Receptor tyrosine kinases regulate cell growth and proliferation of these tumors, and small-molecule inhibitors for many of these kinases are now available. In this article, we review published phase II trials for patients with recurrent disease and highlight the pathways targeted by available agents, as well as the toxicity and efficacy results seen to date. We also discuss the difficulties in identifying biomarkers to facilitate rational patient selection, as well as published and proposed strategies for how these inhibitors can be combined with conventional chemotherapy or other targeted agents. It is hoped future trials can capitalize on this growing experience to optimize the use of this exciting class of agents.

Overcoming therapeutic failure in osteosarcoma via Apatinib-encapsulated hydrophobic poly(ester amide) nanoparticles

Anti-angiogenic tyrosine kinase inhibitors (TKIs) have been proved to be effective in prolonging progression-free survival in advanced osteosarcoma. However, osteosarcoma stem-like cells persist for a long time and ultimately cause disease recurrence and therapy resistance. Here, we reveal that inefficient accumulation of Apatinib, an anti-angiogenic TKI, induces the expression of ribosome-associated genes in osteosarcoma, and confers apoptosis resistance. An engineered nanoscale delivery system based on hydrophobic poly(ester amide) has been established to effectively deliver Apatinib to improve the treatment. Notably, the considerable uptake by osteosarcoma cells enables this nanodrug to distribute increasingly inside the tumor. Furthermore, the delivered nano-Apatinib can suppress osteosarcoma stemness and enhance osteosarcoma stem-like cell apoptosis, and overcomes the crucial bottleneck of the unfavorable stem-like cell residue for TKI therapy. Importantly, nano-Apatinib significantly inhibits the osteosarcoma stem-like cell-derived tumor growth in contrast with free Apatinib, with minimal side effects. These results suggest that this Apatinib-loaded nano delivery system may serve as a promising strategy to solve the issue of TKI therapeutic resistance existing in advanced osteosarcoma.

MiRNA-1225 Inhibits Osteosarcoma Tumor Growth and Progression by Targeting YWHAZ

Introduction

Osteosarcoma is the most common bone tumor and is characterized by the presence of malignant mesenchymal cells produced in the bone stroma. MiRNAs are known to function as post-transcriptional negative regulators of gene expression. Emerging evidence showed that miR-1225-5P functions as a tumor suppressor in several types of cancers. The detailed mechanisms of which miR-1225-5P suppresses tumor growth are not fully understood. The objective of the present study was to test the hypothesis that miR-1225-5P inhibits osteosarcoma cell growth in vitro and tumor growth in vivo by targeting YWHAZ expression.

Methods

Real-time PCR and Western blot were carried out to test the expression of miR-1225-5P and YWHAZ in osteosarcoma cell lines. Luciferase assay was used to demonstrate whether miR-1225-5P targets YWHAZ 3ʹ UTR. To assess the function of miR-1225-5P in human osteosarcoma cell lines, gain-of-function and loss-of-function of miR-1225-5P were performed by transfecting miR-1225-5P mimic or miR-1225-5P inhibitor into osteosarcoma cell lines. Furthermore, cell cycle analysis was performed to elucidate the possible mechanisms of the action of miR-1225-5P and YWHAZ in human osteosarcoma cells. The potential therapeutic effect of miR-1225-5p was tested in human osteosarcoma xenograft mouse model, by intravenous injection of miR-1225-5P into nude mice. Tumor sizes were measured and lung metastasis was counted after the mice were sacrificed.

Results

The expression of miR-1225-5P was inversely correlated with the expression of YWHAZ in human osteosarcoma cell lines. Database search revealed that miR-1225-5P targeted YWHAZ 3ʹ UTR. Transfection of miR-1225-5P mimic downregulated YWHAZ expression, which was demonstrated by real-time PCR, Western blot and luciferase assay. Over-expression of miR-1225-5P reduced human osteosarcoma cell growth, migration and invasion by downregulating YWHAZ expression. Cell growth, migration and invasion were increased by inhibiting miR-1225-5P in human osteosarcoma cells. The inhibition of cell growth, migration and invasion was rescued by over-expression of YWHAZ in osteosarcoma cells. Cell cycle analysis revealed that miR-1225-5P inhibited G1/G0 phase exit. In vivo xenograft model demonstrated that miR-1225-5P inhibited in vivo osteosarcoma tumor growth and lung metastasis.

Conclusion

Our findings suggested that miR-1225-5P inhibits osteosarcoma cell growth in vitro and tumor growth in vivo by targeting YWHAZ. This study suggested that miR-1225-5P can serve as a potential therapeutic method for treating osteosarcoma.

A three-gene signature based on tumour microenvironment predicts overall survival of osteosarcoma in adolescents and young adults

Evidences shows that immune and stroma related genes in the tumour microenvironment (TME) play a key regulator in the prognosis of Osteosarcomas (OSs). The purpose of this study was to develop a TME-related risk model for assessing the prognosis of OSs. 82 OSs cases aged ≤25 years from TARGET were divided into two groups according to the immune/stromal scores that were analyzed by the Estimate algorithm. The differentially expressed genes (DEGs) between the two groups were analyzed and 122 DEGs were revealed. Finally, three genes (COCH, MYOM2 and PDE1B) with the minimum AIC value were derived from 122 DEGs by multivariate cox analysis. The three-gene risk model (3-GRM) could distinguish patients with high risk from the training (TARGET) and validation (GSE21257) cohort. Furthermore, a nomogram model included 3-GRM score and clinical features were developed, with the AUC values in predicting 1, 3 and 5-year survival were 0.971, 0.853 and 0.818, respectively. In addition, in the high 3-GRM score group, the enrichment degrees of infiltrating immune cells were significantly lower and immune-related pathways were markedly suppressed. In summary, this model may be used as a marker to predict survival for OSs patients in adolescent and young adults.