Single-cell and spatial transcriptomics reveal metastasis mechanism and microenvironment remodeling of lymph node in osteosarcoma.

BACKGROUND: Osteosarcoma (OS) is the most common primary malignant bone tumor and is highly prone to metastasis. OS can metastasize to the lymph node (LN) through the lymphatics, and the metastasis of tumor cells reestablishes the immune landscape of the LN, which is conducive to the growth of tumor cells. However, the mechanism of LN metastasis of osteosarcoma and remodeling of the metastatic lymph node (MLN) microenvironment is not clear. METHODS: Single-cell RNA sequencing of 18 samples from paracancerous, primary tumor, and lymph nodes was performed. Then, new signaling axes closely related to metastasis were identified using bioinformatics, in vitro experiments, and immunohistochemistry. The mechanism of remodeling of the LN microenvironment in tumor cells was investigated by integrating single-cell and spatial transcriptomics. RESULTS: From 18 single-cell sequencing samples, we obtained 117,964 cells. The pseudotime analysis revealed that osteoblast(OB) cells may follow a differentiation path from paracancerous tissue (PC) → primary tumor (PT) → MLN or from PC → PT, during the process of LN metastasis. Next, in combination of bioinformatics, in vitro and in vivo experiments, and immunohistochemistry, we determined that ETS2/IBSP, a new signal axis, might promote LN metastasis. Finally, single-cell and spatial dissection uncovered that OS cells could reshape the microenvironment of LN by interacting with various cell components, such as myeloid, cancer-associated fibroblasts (CAFs), and NK/T cells. CONCLUSIONS: Collectively, our research revealed a new molecular mechanism of LN metastasis and clarified how OS cells influenced the LN microenvironment, which might provide new insight for blocking LN metastasis.

Interaction gene set between osteoclasts and regulatory CD4+ T cells can accurately predict the prognosis of patients with osteosarcoma.

Osteoclasts (OCs) and regulatory CD4+ T cells (CD4+ Tregs) are important components in the tumor microenvironment (TME) of osteosarcoma. In this study, we collected six osteosarcoma samples from our previous study (GSE162454). We also integrated a public database (GSE152048), which included single cell sequencing data of 11 osteosarcoma patients. We obtained 138,192 cells and then successfully identified OCs and CD4+ Tregs. Based on the interaction gene set between OCs and CD4+ Tregs, patients from GSE21257 were distinguished into two clusters by consensus clustering analysis. Both the tumor immune microenvironment and survival prognosis between the two clusters were significantly different. Subsequently, five model genes were identified by protein-protein interaction network based on differentially upregulated genes of cluster 2. Quantitative RT-PCR was used to detect their expression in human osteoblast and osteosarcoma cells. A prognostic model was successfully established using these five genes. Kaplan-Meier survival analysis found that patients in the high-risk group had worse survival (p = 0.029). Therefore, our study first found that cell-cell communication between OCs and CD4+ Tregs significantly alters TME and is connected to poor prognosis of OS. The model we constructed can accurately predict prognosis for osteosarcoma patients.

UPLC/Q-TOF-MS-based Metabolomics Study of the Antiosteoporosis Effects of Vaccarin in Ovariectomized Mice.

Osteoporosis is a systemic and metabolic bone disease that usually occurs in postmenopausal women, which mainly manifests as bone loss and increased bone fragility that both facilitate fracture. However, few drugs for osteoporosis have shown good efficacy and limited side effects. Vaccarin has demonstrated its antiosteoporosis effects by inhibiting the formation and osteolytic activities of osteoclasts in our previous investigation. In this study, multivariate statistical analysis and ultrahigh-performance liquid chromatography and quadrupole time-of-flight tandem mass spectrometry were used to analyze the serum metabolites of ovariectomized mice treated with or without vaccarin. As a result, 9 serum metabolites were identified as biomarkers. The metabolic levels of 3 crucial biomarkers, namely, lysophosphatidylcholine [22 : 6, (4Z, 7Z, 10Z, 13Z, 16Z, 19Z)], 1-linoleoylglycerophosphocholine and 1-palmitoyl-Sn-glycero-3-phosphocholine, that were correlated with glycerophospholipid metabolism increased and then decreased significantly after vaccarin treatment. Molecular docking analysis and osteoclasts differentiation experiment further revealed that vaccarin may bind with phospholipase A2 and downregulated its activity to reduce the osteoclastogenesis. Therefore, the occurrence of osteoporosis is closely related with glycerophospholipid metabolism disorders, and vaccarin exerts antiosteoporosis effects by reducing the levels of glycerophospholipid metabolites.

Inhibitory effects of biochanin A on titanium particle-induced osteoclast activation and inflammatory bone resorption via NF-κB and MAPK pathways.

Revision operations have become a new issue after successful artificial joint replacements, and periprosthetic osteolysis leading to prosthetic loosening is the main cause of why the overactivation of osteoclasts (OCs) plays an important role. The effect of biochanin A (BCA) has been examined in osteoporosis, but no study on the role of BCA in prosthetic loosening osteolysis has been conducted yet. In this study, we utilised enzyme-linked immunosorbent assay, computed tomography imaging, and histological analysis. Results showed that BCA downregulated the secretion levels of tumor necrosis factor-α, interleukin-1α (IL-1α), and IL-1ß to suppress inflammatory responses. The secretion levels of receptor-activated nuclear factor-κB ligand, CTX-1, and osteoclast-associated receptor as well as Ti-induced osteolysis were also reduced. BCA effectively inhibited osteoclastogenesis and suppressed hydroxyapatite resorption by downregulating OC-related genes in vitro. Analysis of mechanisms indicated that BCA inhibited the signalling pathways of mitogen-activated protein kinase (P38, extracellular signal-regulated kinase, and c-JUN N-terminal kinase) and nuclear factor-κB (inhibitor κB-α and P65), thereby downregulating the expression of nuclear factor of activated T cell 1 and c-Fos. In conclusion, BCA may be an alternative choice for the prevention of prosthetic loosening caused by OCs.

The role of surgical management of BCG vaccine-induced regional suppurative lymphadenitis in children: a 7 years' experience from one medical center.

BACKGROUND: The management strategy of Bacille Calmette-Guérin (BCG) vaccine-induced regional suppurative lymphadenitis in children is still controversial and more clinical studies are needed. We therefore present a surgical case series to explore the role of surgical management for this dilemma. METHODS: From January 2013 to June 2020, data from 65 patients diagnosed with BCG vaccine-induced regional suppurative lymphadenitis were retrospectively reviewed. Clinical characteristics, ultrasonographic findings, surgical procedures, perioperative management, and outcome were analyzed. The association between postoperative seroma and symptom duration, skin involvement, and postoperative hospital stay were compared using Yates's corrected Chi-square test and Student's t-test for statistical analysis. The follow-up period ranged from three to six months. RESULTS: Of the 65 cases, the median age at presentation was 3.4 months. All patients were full-term with normal range of birth weight and received a BCG vaccination in the first 24 h of life. All patients underwent surgical excision of the abscess with the involved lymph node(s). Postoperative seroma formation was found in 20 patients and fine needle aspiration was needed. There was no significant association between postoperative seroma formation with symptom duration, skin involvement, and postoperative hospital stay. No oral anti-tubercular agents were given postoperatively. The mean length of postoperative hospital stay was 6.02 ± 1.62 days. Sixty-four cases (98.46%) received only one procedure and recovered. One patient required a second procedure due to postoperative sinus. CONCLUSIONS: The present study showed that surgical excision of the abscess with involved lymph node(s) is one of the choices for BCG vaccine-induced suppurative lymphadenitis, but special attention should be paid to controlling the surgical indications. Intraoperative meticulous manipulation and postoperative care are crucial to achieve a good outcome.

Gö6983 attenuates breast cancer-induced osteolysis by the apoptotic pathway.

Bone metastasis caused by breast cancer leads to significant complications in treatment, and the resulting osteolysis considerably affects patients' overall survival and quality of life. Gö6983 is a broad spectrum protein kinase C inhibitor. In this study, based on our finding that the Gö6983 inhibits osteolysis, we applied Gö6983 to the MDA-MB-231 breast cancer-induced mouse bone metastasis model. And we found that Gö6983 has a strong inhibitory effect on the tumorigenic model of breast cancer by promoting the mitochondrial apoptosis pathway. Our study, therefore, demonstrates that Gö6983 has a potential inhibitory effect on breast cancer-induced osteoclast activation and provides mechanistic insight that may prove useful for designing future treatments.

Multiple Diffused Cavernous Hemangiomas Associated with Venous Calculi Formation in the Right Upper Limb and Back: A Case Report.

Cavernous hemangioma, a benign soft tissue and intramuscular tumor, is commonly located in the head, neck, and maxillofacial regions. They can sometimes occur in the limbs and trunk, although rarely. Treatment of cavernous hemangiomas includes surgical and nonsurgical means. Cases of extensive diffused cavernous hemangiomas of an entire limb are rare. In this case presentation, we report the case of chronic diffused cavernous hemangioma associated with venous calculi of the right upper limb and back in a 31-year-old Chinese man. Due to the long history, chronic articular impairments and extensive damage to the skeletal and musculature, surgical amputation of the limb was performed. The aim of this report is to provide further understanding of treatment prioritization and the risks of delayed treatment of cavernous hemangiomas.

Bilateral synovial chondromatosis of the elbow in an adolescent: a case report and literature review.

BACKGROUND: Primary synovial chondromatosis is a rare benign disease that occurs in the joint mucosa. CASE PRESENTATION: In this case report, a 14-year-old gymnast sustained pain in both elbows for 2 months with limited elbow joint activity. The initial diagnosis of bilateral elbow synovial chondromatosis was performed by physical examination and imaging report. Later, the patient was treated with open surgery on both sides of the elbow, including all loose bodies were removed out and the proliferative synovia were cut off. Histopathology reports confirmed synovial chondromatosis. CONCLUSIONS: The report introduced a case about synovial chondromatosis in bilateral elbow found in a 14-year-old girl, which is rarely involved in bilateral elbow and rarely found in adolescents. This case report aims to provide a treatment option for surgeons in similar situations.

Artemisinin inhibits breast cancer-induced osteolysis by inhibiting osteoclast formation and breast cancer cell proliferation.

In addition to being used to treat malaria, artemisinin (Art) can be used as an anti-inflammatory and antitumor agent. In this study, we evaluated the effects of Art on osteoclast formation and activation and on the development of breast cancer cells in bone. To evaluate the effect of Art on osteoclast differentiation in vitro, we treated bone marrow-derived macrophages (BMMs) with various concentrations of Art and evaluated the expression of genes and proteins involved in osteoclast formation. We also performed cell counting kit-8 assays to evaluate the toxicity of Art in BMMs and MDA-MB-231 cells. We also performed Transwell assays, wound-healing assays, colony formation assays, and cell apoptosis assays to evaluate the effect of Art in MDA-MB-231 cells. We also evaluated the effect of Art in an in vivo osteoclast bone resorption assay using a nude mouse model. We demonstrated that Art inhibits the differentiation and establishment of osteoclasts even though Art is not toxic to osteoclasts. In addition, Art reduced expression of genes involved in osteoclast formation and inhibited osteoclast bone resorption in a concentration-dependent manner. Based on our data, we believe that Art can inhibit proliferation of breast cancer cells by activating apoptosis pathways, and inhibit osteoclast formation and differentiation by inhibiting activation of cathepsin K, ATPase H+ transporting V0 subunit D2, nuclear factor of activated T cells 1, calcitonin receptor, and tartrate-resistant acid phosphatase and by inhibiting nuclear factor-κB activation.

Rhoifolin ameliorates titanium particle-stimulated osteolysis and attenuates osteoclastogenesis via RANKL-induced NF-κB and MAPK pathways.

Prosthesis loosening is a highly troublesome clinical problem following total joint arthroplasty. Wear-particle-induced osteoclastogenesis has been shown to be the primary cause of periprosthetic osteolysis that eventually leads to aseptic prosthesis loosening. Therefore, inhibiting osteoclastogenesis is a promising strategy to control periprosthetic osteolysis. The possible mechanism of action of rhoifolin on osteoclastogenesis and titanium particle-induced calvarial osteolysis was examined in this study. The in vitro study showed that rhoifolin could strongly suppress the receptor activators of nuclear factor-κB (NF-κB) ligand-stimulated osteoclastogenesis, hydroxyapatite resorption, F-actin formation, and the gene expression of osteoclast-related genes. Western blot analysis illustrated that rhoifolin could attenuate the NF-κB and mitogen-activated protein kinase pathways, and the expression of transcriptional factors nuclear factor of activated T cells 1 (NFATc1) and c-Fos. Further studies indicated that rhoifolin inhibited p65 translocation to the nucleus and the activity of NFATc1 and NF-κB rhoifolin could decrease the number of tartrate-resistant acid phosphate-positive osteoclasts and titanium particle-induced C57 mouse calvarial bone loss in vivo. In conclusion, our results suggest that rhoifolin can ameliorate the osteoclasts-stimulated osteolysis, and may be a potential agent for the treatment of prosthesis loosening.

Vaccarin prevents titanium particle-induced osteolysis and inhibits RANKL-induced osteoclastogenesis by blocking NF-κB and MAPK signaling pathways.

Wearing titanium particle-induced osteoclastogenesis, accompanied by peri-implant osteolysis, is the main cause of long-term failure of hip prosthesis. Currently, medications used for the prevention and treatment of peri-implant osteolysis show serious side effects. Therefore, development for more effective new drugs with less side effects is extremely urgent. Vaccarin is a natural flavonoid extracted from Vaccaria segetalis, with various biological functions, including antioxidantory, anti-inflammatory, and promotion of angiogenesis. However, the putative role of vaccarin in the inhibition of titanium particle-induced osteolysis has not been reported. In this study, it was indicated that vaccarin could effectively inhibit RANKL-induced osteoclastogenesis, fusion of F-actin rings, bone resorption, and expression of osteoclast marker genes in a dose-dependent manner in vitro. Moreover, vaccarin could also inhibit RANKL-induced osteoclastogenesis via the inhibition of NF-κB and MAPK (p38, ERK, and JNK) signaling pathways, and inhibit the transcription of downstream transcription factors, such as c-Fos and NFATc1. Consistent with in vitro results, this in vivo study showed that vaccarin exhibited an inhibitory effect on titanium particle-induced osteolysis by antiosteoclastogenesis. In conclusion, vaccarin could be a promising agent for preventing and treating peri-implant osteolysis.

Ligustilide suppresses RANKL-induced osteoclastogenesis and bone resorption via inhibition of RANK expression.

Osteoclast (OC) is the only cell involved in bone resorption. Dysfunction of OCs leads to a variety of bone diseases. Ligustilide (LIG) is the main component of the volatile oil isolated and purified from Angelica sinensis. LIG exerts many pharmacological activities, but its effects on osteoclastogenesis and bone resorption are still unclear. Our study showed that LIG inhibited receptor activator of nuclear factor-κB (NF-κB) ligand-induced OC formation and activation in a dose-dependent manner. Additionally, LIG downregulated the messenger RNA (mRNA) expression of OC-specific genes, such as V-ATPase d2, tartrate-resistant acid phosphatase, a dendritic cell-specific transmembrane protein, cathepsin K, and nuclear factor of activated T cells cl. Furthermore, LIG blocked the activation of NF-κB/extracellular signal-regulated kinase/p38/immunoreceptor tyrosine-based activation motif signaling pathways. Crucially, the expression of tumor necrosis factor receptor-associated factor 6 proteins and the expression of receptor activator of NF-κB mRNA were inhibited by LIG. However, LIG did not affect the formation and mineralization of osteoblasts. Collectively, this observation suggests that LIG may serve as a promising agent for the prevention and treatment of diseases caused by abnormal bone resorption.

Giant cell tumors combined with secondary aneurysmal bone cysts are more likely to develop postoperative recurrence: A retrospective study of 256 cases.

PURPOSE: The epidemiology and clinicopathology of aneurysmal bone cysts (ABCs) secondary to giant cell tumors of bone (GCTBs) have been well documented in the previous literature. However, reports on whether secondary ABCs could affect the postoperative recurrence of GCTBs are rare. This study analyzed the effects of secondary ABCs and other relevant clinical factors on the postoperative recurrence of GCTBs of the extremities. METHODS: We retrospectively analyzed 256 cases of GCTBs of the extremities that were treated surgically at our institution. Among them, there were 60 patients diagnosed with GCTBs combined with secondary ABCs and 196 patients diagnosed with simple GCTBs. Intralesional curettage and tumor resection were performed in 136 and 120 cases, respectively. Univariate analysis, Kaplan-Meier survival analysis, and multivariate regression analysis were used to assess the factors for postoperative recurrence. The follow-up period was at least 24 months. RESULTS: The total postoperative recurrence rate was 32%. The recurrence rate in the secondary ABCs group was significantly higher than that in the simple GCTBs group (53.3% vs 25.5%, P < 0.05). Curettage was associated with a higher recurrence rate than tumor resection (42.5% vs 20%, P < 0.05). Kaplan-Meier survival analysis showed that patients with GCTBs combined with secondary ABCs and who were treated by intralesional curettage had a decreased disease-free survival rate. The hazard ratio was 2.18 (95% confidence interval [CI], 1.15-4.13) for the group of GCTB combined with ABCs ( P = 0.01) and 1.97 (95% CI, 1.22-7.50) for the curettage group ( P = 0.01), respectively. Multivariate regression analysis revealed that the presence of secondary ABCs and curettage were independent factors for recurrence of GCTBs. CONCLUSION: According to the results of this study, the presence of secondary ABCs is a potential risk factor for postoperative relapse of GCTBs.

Analysis of the clinical efficacy of tumor resection methods used in 20 patients with clavicular tumor.

BACKGROUND: To retrospectively analyze the tumor resection method used in 20 patients with clavicular tumors and evaluate its clinical efficacy. METHODS: A total of 9 patients with clavicular benign tumors underwent intracapsular resection, and 11 patients with clavicular malignant tumors underwent tumor resection from May 2012 to May 2017. Of the 11 patients, 5 underwent clavicular reconstruction using the plate-cement complex. Surgical efficacy was assessed using the Musculoskeletal Tumor Society, Constant-Murley, and American Shoulder and Elbow Surgeons shoulder outcome scores preoperatively until 12 months postoperatively. RESULTS: The average duration of follow-up care was 33.7 (12-71) months. Of the 20 patients, 3 patients died, 3 survived with tumor recurrence or metastasis, and 14 survived with no tumor recurrence. Among the 5 patients who underwent resection of malignant clavicular tumors and reconstruction, 2 underwent a re-operation because of a loose screw and plate displacement. In the functional assessment of the shoulder joint, patients with benign and malignant clavicular tumors showed significantly higher scores postoperatively compared with preoperative scores. For malignant clavicular tumors, no significant improvement was observed when comparing the non-reconstruction and reconstruction groups. CONCLUSIONS: Surgery is an optimal treatment for clavicular tumors. In patients with benign clavicular tumors, simple intracapsular resection can achieve a satisfactory prognosis. Reconstruction of a clavicular defect after resection of a clavicular malignant tumor is not recommended.

Gö6983 attenuates titanium particle-induced osteolysis and RANKL mediated osteoclastogenesis through the suppression of NFκB/JNK/p38 pathways.

Osteoclast activation by wear particles has caused major difficulties for surgeons. Wear particles are the main causes of aseptic prosthetic loosening. Gö6983, a protein kinase C inhibitor, inhibits five subtypes of protein kinase C family members. Here, we found that Gö6983 had an obviously inhibitory effect on wear-particles-induced osteolysis in vivo. In vitro, Gö6983 inhibited RANKL-stimulated osteoclast formation and function by inhibiting the RANKL-stimulated nuclear factor-κB/JNK/p38 signaling pathway. We also observed that Go6983 had no effect on the differentiation of osteoblasts and osteoblast-associated genes expression. According to our data, Gö6983 has potential therapeutic effects for aseptic prosthetic loosening caused by osteoclast activation.

Effect of One-methylcyclopropene (1-MCP) and chlorine dioxide (ClO2) on preservation of green walnut fruit and kernel traits.

The effect of the ethylene receptor competitor 1-methylcyclopropene (1-MCP) and the legally approved disinfectant chlorine dioxide (ClO2) on preservation of the green walnut fruit during storage was investigated. Green Chinese walnut fruit cv. Xilin No.2 was harvested on commercial maturity and stored at 0-1 °C after the fruit was treated by water (control), 80 mg L(-1)ClO2 (ClO2), 0.5 µL L(-1)1-MCP (1-MCP), or combination treatment of 80 mg L(-1) ClO2 with either 0.1 µL L(-1) 1-MCP (0.1 1-MCP+ ClO2) or 0.5 µL L(-1) 1-MCP (0.5 1-MCP+ ClO2). During storage, respiration, ethylene production, phenolics content, antioxidative activity, weight changes, decay of the fruit and kernel traits of acid value, peroxide value,free fatty were measured. All treatments decreased postharvest respiration intensity in different degrees and inhibited ethylene production peak. ClO2 increased the total phenol and flavonoid content of the green fruit compared with other treatments and the control (P < 0.05), but not did the total antioxidant activity for this treatment. After 42-day storage, ClO2 remained higher fresh weight and lower decay index than control, while 1-MCP increased the fruit decay index. Final acid values of kernel from ClO2, control and 0.1 1-MCP+ ClO2 were not different from their initial values, which from 0.5 1-MCP increased. Final peroxide value for kernel from ClO2 showed no change during storage but increased at least 1.0-fold for other treatments. ClO2 preserved 99.9 % of initial free fatty acid, similar to that for the control (99.8 %), whereas 0.5 1-MCP preserved only 95.7 %. ClO2 is of potential in decay retardation and kernel traits maintenance of green walnut fruit, whereas the 1-MCP has a negative effect for decay control on walnut.

Deep removal of trace arsenic from acidic SbCl3 solution by in-situ galvanically coupled Cu2Sb/Cu particles.

Arsenic is a harmful associated element in antimony ore, which might bring out the risk of leakage during complex industrial production of high-purity antimony. Herein, we reported a novel and efficient way to remove the trace arsenic impurity from acidic SbCl3 solution by utilizing copper-system bimetallic particles. Specifically, galvanically coupled Cu2Sb/Cu was in-situ synthesized by introducing precursor copper powder to the specific SbCl3 solution. DFT studies revealed that Sb(III) was easily reduced by Cu to form Cu2Sb due to the strong adsorption of Sb(III) on Cu (111) crystal plane. The Cu2Sb/Cu coupling exhibited excellent activity for As(III) reduction, over 99.4% arsenic were removed under optimal conditions and residual arsenic concentration dropped to only 2.7 mg L-1. Crucially, Sb(III) concentration changes could be neglected. Besides, the dearsenization residues were extensively characterized to analyze the evolvement and cause in the reaction process. The results confirmed that the arsenic removal mechanisms by Cu2Sb/Cu particles were multi-affected, including adsorption, displacement, and precipitation. And the strong electrostatic attraction of AsO+ under high HCl conditions was identified as a key step to achieving dearsenization. This research will provide a theoretical guidance for the green synthesis of high-purity antimony and related products.

Single-cell RNA sequencing reveals the immune microenvironment landscape of osteosarcoma before and after chemotherapy.

Chemotherapy, a primary treatment for osteosarcoma (OS), has limited knowledge regarding its impact on tumor immune microenvironment (TIME). Here, tissues from 6 chemotherapy-naive OS patients underwent single-cell RNA sequencing (scRNA-seq) and were analyzed alongside public dataset (GSE152048) containing 7 post-chemotherapy OS tissues. CD45+ (PTPRC+) cells were used for cell clustering and annotation. Changes in immune cell composition pre- and post-chemotherapy were characterized. Totally, 28,636 high-quality CD45+ (PTPRC+) cells were extracted. Following chemotherapy, the proportions of regulatory T cells (Tregs) and activated CD8 T cells decreased, while CD8 effector T cells increased. GO analysis indicated that differentially expressed genes (DEGs) in T cells were associated with cell activation, adaptive immune response, and immune response to tumor cells. Furthermore, the proportions of plasma cells increased, while naive B cells decreased. B cell surface receptors expression was upregulated, and GO analysis revealed DEGs of B cells were mainly enriched in B cell-mediated immunity and B cell activation. Moreover, M2 polarization of macrophages was suppressed post-chemotherapy. Overall, this study elucidates chemotherapy remodels the OS TIME landscape, triggering immune heterogeneity and enhancing anti-tumor properties.

Development and validation of neutrophil extracellular traps-derived signature to predict the prognosis for osteosarcoma patients.

Neutrophil extracellular traps (NETs) have been reported to be crucial in tumorigenesis and malignant progression. However, their prognostic significance, association with tumor immune microenvironment (TIME), and therapeutic response in osteosarcoma (OS) stills remain unclear. Hence, TARGET and GSE21257 cohorts were included for analysis. Single-sample gene set enrichment analysis (ssGSEA) and weighted gene co-expression network analysis (WGCNA) were conducted to extract NETs-derived genes. Subsequently, the NETs score (NETScore) model, consisting of 4 signature genes, was established and validated with the least absolute shrinkage and selection operator (LASSO) and Cox regression analysis. Our results indicated that NETScore has satisfactory predictability of the patient's overall survival, with AUC values at 1-, 3- and 5-year in the training cohort of 0.798, 0.792 and 0.804, respectively; similar prominent prediction performance was obtained in three validation cohorts. Further, real-time quantitative PCR (RT-qPCR) assay was conducted to determine the expression of signature genes in human osteoblasts and OS cells. Besides, NETScore and clinical factors (age, gender, metastatic status) were integrated to construct a nomogram. C-index and AUC values at 1-, 3-, and 5-year were above 0.800, displaying robust predictive performance. Patients with high and low NETScore had different immune statuses and drug sensitivity. Meanwhile, several positive regulatory immune function pathways, including T cell proliferation, activation and migration, were significantly suppressed among patients with high NETScore. Summarily, we established a novel NETScore that can accurately predict OS patients' prognosis, which correlated closely with the immune landscape and therapeutic response and might help to guide clinical decision-making.