Anti-tumor effects of Guggulsterone in osteosarcoma: Role of SIRT3-mediated PINK1-Parkin mitophagy activation.

Osteosarcoma (OS) is a malignant primary bone tumor developing from primitive mesenchymal cells. Glycosylation is important in the adhesion, metastasis and transformation of cancer cells. Nevertheless, the investigation of glycosylation-related genes (GRGs) in OS has been infrequently described. The OS-related datasets (GSE36001, TARGET-OS and GSE21257), scRNA-seq dataset (GSE152048) and 582 GRGs were contained in this research. The identification of candidate genes was conducted by differential expression analysis and weighted gene co-expression network analysis (WGCNA). The prognostic genes filtering method was univariate cox regression, and risk score were generated by the implementation of LASSO. Samples comprising the TARGET-OS and GSE21257 datasets were categorized into high- and low-risk according to the risk score. Through applying various cox regression analysis, independent prognostic variables were identified. Furthermore, functional enrichment analysis and immune microenvironment analysis were performed. Finally, the key cells were identified, and the cell-cell communication and pseudo-time analyses of key cells were conducted. The analysis of scRNA-seq data identified cell types in OS and detected the expression of prognostic genes. Seven glycosylation-related genes (DCN, RENBP, UAP1, B4GALNT1, CCDC115, TUBA1A and B3GALT4) were identified as prognostic genes. The low-risk group exhibited a comparatively elevated rate of survival and 1-year OS patients had the highest survival rate. Immune and apoptosis-related signaling pathways were activated in the high-risk group, indicating a worse prognosis. The analysis of scRNA-seq data revealed DCN and TUBA1A were high- expressed in osteoblastic cells. Thus, the osteoblastic cells were identified as key cells. Osteoblastic cells exhibited frequent interactions with other annotated cells. Pseudo-time analysis elucidated the differentiation direction of key cells from left to right. we identified seven prognostic genes for OS. The prognostic models were constructed, and underlying molecular mechanisms were explored based on diagnostic genes, which served as a benchmark for OS prognosis and treatment.

Construction and validation of an osteosarcoma prognostic model reveals that SERPINE2 contributes to the progression and cisplatin sensitivity in osteosarcoma.

Background Emerging evidence implicates N6-methyladenosine (m6A) RNA modification in osteosarcoma (OS) pathogenesis, but the downstream effectors and regulatory networks remain not fully elucidated. Cyclin-dependent kinase subunit 2 (CKS2) has been identified as a potential key player in OS. This study investigates its role in OS progression and its regulation via METTL3-mediated m6A modification. Methods Differentially expressed genes (DEGs) were analyzed using the GSE16088 dataset from the GEO database. Candidate targets were validated in OS tissues by qRT-PCR, and the gene with the highest fold change was selected. The role of CKS2 was examined using in vitro and in vivo assays. The relationships among CKS2, METTL3, and IGF2BP1 were analyzed via bioinformatics, correlation analysis, RIP, MeRIP, qRT-PCR, Western blotting, and mRNA stability assays. Rescue experiments explored the functional relationship between METTL3 and CKS2. Results CKS2 was identified as one of the most upregulated genes in OS, a finding confirmed in OS tissues. Its silencing suppressed OS cell proliferation, colony formation, migration, invasion, and tumor growth. Furthermore, METTL3 expression was positively associated with CKS2 levels, and METTL3 overexpression increased CKS2 mRNA stability in an m6A-dependent manner. Interestingly, IGF2BP1 bound directly to m6A-modified CKS2 transcripts and maintained their stability. Functionally, METTL3 overexpression partially rescued the suppressive effects of CKS2 silencing on OS cells. Conclusions Our study identified a METTL3/IGF2BP1–CKS2 axis that promotes OS progression via m6A-dependent mRNA stabilization, highlighting CKS2 as a potential therapeutic target.

Fluorinated polymeric nanoplatform relieves tumor hypoxia and enhances chemo-sonodynamic therapy.

Characterizing two subtypes of osteosarcoma using G2M checkpoint-related genes and revealing its immune landscape.

Ion interference induced by Ca-Mn nanoplatform enhances ferroptosis and promotes immune response for osteosarcoma treatment.

Cisplatin (Cis) is widely recognized as the cornerstone of osteosarcoma (OS) chemotherapy. However, its clinical effectiveness remains limited by poor drug delivery efficiency, severe adverse effects, and emerging chemoresistance. To overcome these limitations, a triple-drug co-delivery system (NP3) is designed, encapsulating Cis prodrug (Cis(IV)), curcumin (Cur), and manganese ions within reactive oxygen species (ROS)-responsive nanoparticles (NPs). NP3 efficiently accumulated at tumor sites and rapidly released its therapeutic payload upon endocytosis, triggered by abundant intracellular ROS. After NP3 degradation, Cis in combination with Cur induced significant DNA damage. This DNA debris subsequently activated the cGAS-STING pathway, enhancing tumor immunogenicity. Additionally, manganese ions functioned as immune adjuvants, further amplifying cGAS-STING activation. Consequently, NP3 promoted dendritic cell (DC) maturation, enhanced the infiltration of CD8+ T-cells, and concurrently decreased the infiltration of immunosuppressive cells. In an OS mouse model, combining NP3 with anti-PD-L1 treatment markedly improved both tumor suppression and immune system activation. RNA sequencing analysis demonstrated that NP3 synergistically promoted tumor regression by concurrently inducing pro-apoptotic signaling and immune responses. In conclusion, this study presents an innovative therapeutic strategy combining targeted chemotherapy delivery with robust antitumor metalloimmunotherapy, offering a promising therapeutic approach for OS.

On-exosome-membrane DNA polymerization-powered magneto-electrochemical aptasensing for osteosarcoma.

To investigate whether metabolic and volumetric 18F-FDG PET parameters are associated with histopathological response, metastatic disease at diagnosis, overall survival (OS), and progression-free survival (PFS) in pediatric osteosarcoma (OST) patients. Additionally, to compare absolute and relative threshold methods for metabolic tumor volume (MTV) calculation. This single-center retrospective study included 26 pediatric OST patients who underwent 18F-FDG PET/CT at diagnosis and, when available, after neoadjuvant chemotherapy. SUVmax, SUVpeak, MTV, total lesion glycolysis (TLG) and anatomic tumor volume of the primary tumor, along with whole-body MTV (wb-MTV) and whole-body TLG encompassing all FDG-avid metastatic lesions, were measured and their percentage changes (∆) between PET scans were calculated. MTV and TLG were calculated using absolute (SUV 2.0) and relative (40% of tumor SUVmax) threshold methods. Baseline 18F-FDG PET parameters did not predict histopathological response. But, we found that ΔSUVmax, ΔMTV (2.0), ΔTLG (2.0), and ΔTLG (40%) were associated with histopathological response (p = 0.029). Although not statistically significant, patients with metastases had higher baseline SUVmax, SUVpeak, MTV (2.0), and TLG (2.0) values. Anatomic tumor volume did not differ between the metastatic and localized groups. Patients with wb-MTV (40%) > 137.5 had a significantly higher mortality risk (HR = 4.27, p = 0.017). Kaplan-Meier analysis revealed that patients with primary tumors exhibiting SUVmax > 5.56 and SUVpeak > 4.57 had significantly lower estimated 5-year OS rates (p = 0.036 and 0.029), even after excluding patients with metastasis at diagnosis. ΔSUVmax, ΔMTV (2.0), ΔTLG (2.0), and ΔTLG (40%) were found to be associated with histopathologic response, suggesting that these changes may serve as predictors of histopathologic outcome. MTV (2.0) may be a more reliable indicator of tumor aggressiveness than anatomic tumor volume, as it tended to be higher in the metastatic group. Our finding suggests that using absolute threshold may better reflect tumor burden in primary lesions with high metabolic activity, whereas relative threshold may be more suitable for evaluating total tumor burden, including low 18F-FDG uptake metastases. Inferior survival outcome is associated with elevated baseline SUVmax and SUVpeak values persisted even when patients with metastatic disease were excluded, suggesting their potential prognostic value.

Multifunctional scaffold integrating chemo/photothermal therapy and bone defect reconstruction for osteosarcoma: An in vitro evaluation.

Pet dogs with naturally occurring cancers provide valuable models for comparative oncology and pathology tumour registries offer a powerful resource for onco-epidemiological research. Here, we analysed the Small Animal Veterinary Surveillance Network (SAVSNET) pathology-based tumour registry (PTR), one of the largest veterinary tumour registries to date, focusing on four major canine tumours: mast cell tumour (MCT), osteosarcoma (OSA), haemangiosarcoma (HSA), and melanoma (MEL). A case-control study was conducted using a subset of 130 998 histologically confirmed tumours drawn from the pathology tumour registry containing over 1.1 million canine tumour records from 1.02 million dogs collected in the UK between 2010 and 2023. Case-control analyses were performed for melanoma, haemangiosarcoma, OSA and MCT using a denominator population of dogs attending first-opinion veterinary practices. Additionally for MCT, comparisons were made against dogs diagnosed with other tumour types ('tumour denominator' approach). Breed-specific risks were identified, including high odds ratios (OR) for Bulldog-related breeds and Retrievers with mast cell tumours (MCTs) (OR up to 6.8, 95% CI 6.0, 7.6), Rottweilers, Shar Pei and Giant-Schnauzer with melanoma (OR up to 50.3, 95% CI 24.7, 102.5), and German Shepherd Dogs, Mastiffs, and Bullmastiffs with haemangiosarcoma (OR up to 28.0, 95% CI 10.6, 40.9). Higher-grade MCT were diagnosed at older ages and certain breeds were more predisposed to higher-grade MCT (Shar Pei, Rottweiler) while others were more prone to low-grade MCTs (Boxer, Boston Terrier). Neutered dogs generally had higher tumour odds than entire dogs; for example, in MCTs, female-neutered vs. female-entire showed OR 1.81 (95% CI 1.6, 2.0) in ages 3-6, with similar patterns across older age bands. In general, the difference in OR values between entire and neutered dogs was consistently more pronounced in females than in males. These findings demonstrate the value of the SAVSNET PTR as a comprehensive resource for canine tumour surveillance, with potential to support health initiatives and cancer research by identifying breed-specific and demographic risk factors as well as a foundational tool for comparative cancer epidemiology.

Osteosarcoma (OS) is a primary malignant bone tumor often treated by surgical resection and systemic chemotherapy, which can cause severe side effects and nonspecific drug distribution. Localized drug delivery via bone scaffolds offers a promising alternative but faces limitations such as poor drug retention, instability of therapeutics, and insufficient mechanical strength for bone repair. This study presents a multifunctional implant integrating doxorubicin (DOX)‐loaded liposomes into Baghdadite (Ca 3 ZrSi 2 O 9 , BAG) ceramics. Ion‐assisted plasma polymer (IPP) coating was employed to enhance liposome immobilization and control DOX release. BAG functionalized with DOX‐loaded liposomes (BAG/DOXlipo) significantly reduced OS cell viability, with enhanced efficacy observed in IPP‐coated samples. Notably, BAG/DOXlipo (with or without IPP) showed no cytotoxicity to human osteoblasts, supported sustained ion release, and promoted alkaline phosphatase activity and bone mineralization. Additionally, the BAG/DOXlipo system demonstrated antibacterial activity against common implant‐related pathogens. This platform uniquely combines mechanical robustness, osteoconductivity, and covalently bound liposomal chemotherapeutics to achieve localized tumor inhibition, bone regeneration, and infection control. It offers a promising strategy for OS treatment while minimizing systemic toxicity.

Gnathic osteosarcoma (OS), which includes mandibular and maxillary jaw OSs, account for 6%-9% of OS. Single-institutional and multi-institutional retrospective studies, as well as population-level databases, suggest that clinical differences exist among gnathic OS and OS of other sides, including other craniofacial OS. To date, no specific prospective studies of gnathic OS have been reported, and aspects of clinical management are controversial. Some elements of care are aligned with extragnathic OS, e.g., margin negative (R0) surgery, whereas others, such as chemotherapy and radiation, are not clearly defined. The authors reviewed the available literature for the diagnosis, treatment, and supportive/survivorship care patients with gnathic OS and offer consensus statements for the comprehensive management of this rare disease.

Osteosarcoma (OS) is one of the most malignant bone tumors in children and adolescents, but the molecular mechanisms of OS progression remain largely undefined. In this study, we demonstrate that Integrin subunit beta-like 1 (ITGBL1) is downregulated in OS tissues, and its downregulation correlates with poor prognosis in OS patients. Functional assays revealed that ITGBL1 inhibits OS cell growth, metastasis, and stemness, while promoting apoptosis. The in vitro and in vivo experiments further revealed that ITGBL1 activates endoplasmic reticulum (ER) stress by upregulating ROS, thereby triggering autophagy in OS cells. In addition, the downregulation of ITGBL1 in OS is partly attributed to the abnormal upregulation of HSP90AB1 (heat shock protein 90 alpha family class B1). Mechanistically, ITGBL1 interacts with HSP90AB1 which facilitates ITGBL1 degradation through K63-linked ubiquitination. Finally, through virtual screening and Co-IP, we identified ivermectin as a potent inhibitor of the HSP90AB1-ITGBL1 interaction, and treatment with ivermectin dramatically inhibited OS progression in vivo. In conclusion, we uncover a novel mechanism that promotes OS progression and identify a new candidate drug for the treatment of OS.

Cancer is the leading cause of death among children and adolescents in high-income countries. Among solid tumors, osteosarcoma (OS) is the most prevalent primary bone cancer in the pediatric population. For patients who relapse or develop metastases, the survival rate remains at only 30%, with scarce improvement over the past 30years. Immunotherapy, including chimeric antigen receptor (CAR) T cells, represents a promising approach to treating OS. We observed that despite robust in vitro cytotoxicity of NKG2D-CAR T at low effector-to-target ratios, NKG2D-CAR T cells failed to control tumor growth in our xenograft OS models, highlighting the suppressive tumor microenvironment (TME). In this regard, the hypoxic TME has been widely considered a barrier to effective immunotherapies. Here, we examined the impact of hypoxia on NKG2D-CAR T function in OS in vitro models. We confirmed HIF-1α is highly expressed in our OS models, indicating the potential of hypoxia as a CAR T disruptor. However, hypoxia was not responsible for lowering NKG2D ligands expression for CAR recognition, nor did it impact the expression of major activating or inhibitory immune checkpoints. Crucially, functional assays demonstrated that NKG2D-CAR T cell phenotype, activity, and cytokine secretion remained unaffected and its activity against three-dimensional OS-spheroids was preserved under in vitro hypoxic conditions. Although these findings challenge the idea that hypoxia alone compromises in vitro NKG2D-CAR T efficacy in OS, further studies are needed on how hypoxia interacts with multiple factors of the TME that could modulate CAR T cell behavior.

ABSTRACTBackgroundOsteosarcoma is a primary bone malignancy with a known bimodal age distribution. However, epidemiological patterns based on precise primary anatomical sites are not well characterized. This population‐based study analyzed the Surveillance, Epidemiology, and End Results (SEER) database to compare the incidence and clinical features of central‐site versus peripheral‐site osteosarcoma across different age groups.AimsThis study aimed to compare the incidence characteristics of peripheral and central‐site osteosarcoma (OS) and to explore the impact of different primary sites on the prognosis of patients with OS.MethodsPatients diagnosed with OS (1975–2019) were selected from the SEER databases. The different primary sites, diagnosis time, and incidence of OS were described statistically. A 1:1 propensity score matching (PSM) was used to adjust for clinical characteristics and treatment. Kaplan–Meier curves were used to compare overall survival and CSS of peripheral and central‐site OS before and after matching. Univariate and multivariate Cox models were used to investigate prognostic factors for CSS in both groups.ResultsA total of 3129 patients were included (899/28.73% central‐site OS, 2166/69.22% peripheral‐site OS, 64/2.05% other‐site OS). After PSM, central‐site OS had lower overall survival and CSS than peripheral‐site OS (5‐year overall survival, 0.415 vs. 0.468; 5‐year CSS, 0.454 vs. 0.555). Multivariate analysis revealed that age (p = 0.010), primary site (p = 0.039), historical SEER stage (regional, p = 0.012; distant, p < 0.001), histologic grade (grade III, p = 0.014; grade IV, p = 0.009), surgery (p < 0.001), and radiotherapy (p = 0.005) were significant factors for CSS. Subgroup analyses adjusting for these factors showed better CSS in peripheral‐site OS patients.ConclusionsThe incidence of central‐site OS is lower than that of peripheral‐site OS, while the prognosis of patients with peripheral‐site OS is more favorable than that of patients with central‐site OS. Surgical intervention is a cornerstone in the management of OS and is effective for both central‐site and peripheral‐site OS.

BackgroundLiquid-liquid phase separation (LLPS) contributes to osteosarcoma (OS) regulatory mechanisms. This investigation focused on evaluating the predictive potential of LLPS-related genes (LRGs) for OS.MethodsLRGs were obtained from the data resource of LLPS (DrLLPS) database. Transcriptome data from OS patients were downloaded from The Cancer Genome Atlas (TCGA)-Target and Gene Expression Omnibus (GEO) databases, and differentially expressed genes (DEGs) and key module genes for OS were identified through differential expression analysis and weighted gene co-expression network analysis (WGCNA). Univariate Cox regression and machine learning, including least absolute shrinkage and selection operator (LASSO), random forest (RF), and XGBoost, were used to identify hub differentially expressed LRGs (DELRGs), and their predictive value was assessed. Single-gene gene set enrichment analysis (GSEA), immune infiltration, and drug sensitivity analyses were conducted. In vitro experiments verified bioinformatics results.ResultsBy intersecting DEGs, key module genes, and LRGs, 221 DELRGs were obtained. Four genes (MRPL12, GCA, ABLIM1, and MAGED1) were identified as hub DELRGs with excellent predictive value in OS. Single-gene GSEA highlighted the regulatory roles of hub DELRGs in OS. Neutrophils were significantly correlated with all four hub DELRGs. These genes were extensively correlated with drug sensitivity. MRPL12 levels were upregulated, while MAGED1, ABLIM1, and GCA levels were downregulated in OS cells, consistent with bioinformatics-predicted expression and prognostic significance of GCA and MRPL12. MRPL12 knockdown or GCA overexpression inhibited the malignant phenotypes of U2OS cells.ConclusionsThis study identified four hub DELRGs for OS prognosis, offering insight into LLPS in OS pathogenesis.

Osteosarcoma (OS) is the most common primary bone malignancy affecting children and adolescents, for which survival has not improved in more than four decades. The lack of accurate OS preclinical models hinders the understanding of tumor heterogeneity and its interaction with the surrounding extracellular matrix (ECM), limiting the discovery of predictive biomarkers and the development of effective therapies. Four 2D preclinical models from OS patients were established and characterized for their functional differences in comparison to OS cell lines for their growth, cellular phenotypic attributes, osteogenic differentiation capabilities and metabolic responses to growth factors and BMP-2. Molecular and cellular profiling revealed intra-tumoral heterogeneities that were very distinct from the endorsed OS cell lines. The OS patient-derived (PD) cells also displayed differential sensitivity to Doxorubicin and Cisplatin and resistance against Methotrexate. Subsequently, the 3D PDTs (Patient- derived tumoroids) models were developed by self-aggregating spheroids with and without Matrigel® ECM matrix. These PDTs models were screened for selective ECM and bone-specific gene markers, revealing dynamic differences between 2D and 3D models with and without ECM, with heightened dysregulation observed in 3D systems. The drug response variances observed among 2D OS cells and 3D tumoroids model within Matrigel® highlights the need for optimized platforms forin vitropersonalized drug screening. Thus, our findings support the screening of preclinical PD OS models for phenotypic profiling and elucidating ECM contributions to drug responses and pathophysiology.

Previous studies have demonstrated that the USP14 inhibitor IU1 and USP14/UCHL5 inhibitor b-AP15 can extend the survival period of TP53-deficient mice with spontaneous osteosarcoma (OS). However, the underlying molecular mechanisms remain to be fully elucidated. The transmembrane protein TMEM158 has been identified as a key regulator in the progression of various cancers. Nevertheless, its functional role in OS remains largely unknown. In this study, we conducted comprehensive bioinformatics analyses-including cluster analysis, differential expression analysis, and functional enrichment analysis-on clinical OS databases to assess the correlation between TMEM158 expression and the proteasome-associated USP14 and UCHL5. Primary tumor cells (TP53-deficient OS cells), SAOS-2 and U-2OS cells were treated with IU1 or b-AP15, respectively. The expression levels of TMEM158 were quantified using qPCR. Subsequently, TMEM158 was knocked down in three cell lines, and subsequent changes in cellular activity and TGF-β signaling were evaluated. Concurrently, single-cell RNA sequencing data were analyzed to identify cell types exhibiting high TMEM158 expression and to explore their associated intercellular communication patterns. Both IU1 and b-AP15 significantly prolonged the survival of TP53-deficient OS mice and exhibited enhanced cytotoxic effects on TP53-deficient OS cells. These compounds selectively suppressed TMEM158 expression in TP53-deficient primary OS and SAOS-2 cells. Bioinformatics analysis revealed that TMEM158 is positively correlated with USP14 and UCHL5 expression and serves as an independent prognostic marker for poor clinical outcomes in OS patients. Experimental validation showed that TMEM158 knockdown significantly reduced the viability of TP53-deficient primary OS and SAOS-2 cells, and inhibited TGF-β pathway activation. Osteoblastic OS cells displayed concurrent suppression of the P53 pathway and activation of the TGF-β pathway, with a strong covariant relationship between TMEM158 and activity of TGF-β pathway. Meanwhile, there may be intercellular TGF-β signaling communication between osteoblastic OS cells with high expression levels of TMEM158 and macrophages. Our findings demonstrated that the TMEM158-TGF-β pathway plays a central role in mediating the heightened sensitivity of TP53-deficient OS to USP14 inhibition. Targeting this pathway may represent a promising therapeutic strategy for precision treatment of osteosarcoma.