Search Results (1,167)

Current standard treatments for osteosarcoma have not been changed for decades and have limited and variable success. The advancement of precision medicine technologies, along with the drug-repurposing and fast drug-screening methodologies available, has opened new avenues for the development of more effective therapeutic strategies. In this study, we evaluated the effectiveness of halogenated boroxine (HB) and dextran-coated cerium oxide nanoparticles—DexCeNPs (SD2)—in an in vitro osteosarcoma model. Both agents were tested individually and in combination. The research encompassed assessments of treatment-related cytotoxicity and cell viability, oxidative stress, and apoptotic and necrotic responses, as well as the effects on 3D spheroid models. The results demonstrated that the effects of HB and SD2 were strongly influenced by the dose, exposure time, and cell type. Both exhibited distinguished antitumor activity through cytotoxicity and specific reactive oxygen species (ROS) induction. The combined treatment produced modulated responses that were dependent on the treatment ratio and cell line, suggesting potential synergistic or selective interactions. Notably, the outcomes of the analysis conducted in 3D models revealed reduced toxicity toward non-tumor cells. These findings suggest the improved efficacy of HB and SD2 used in combination as a selective and novel antitumor strategy and underscore the need for further mechanistic studies at the transcriptomic and proteomic levels to elucidate the underlying pathways and clarify the mechanisms of action. Full article

Survival rates for those with metastatic osteosarcoma (OS) have not improved over the last four decades. It is imperative that novel approaches to treating and curing OS be sought. We, therefore, turned our attention to Brusatol (Bru), a naturally occurring Nrf2 inhibitor reported to elicit anti-cancer effects in a multitude of tumour models. Importantly there is emerging evidence that Nrf2 is implicated in chemoradiotherapy resistance in OS and that inhibiting Nrf2 may represent a desirable route to treating OS. Surprisingly, using the human OS cell line, MG63, we actually found that Bru promoted cell growth. Compared to control, normoxic cultures, the application of Bru (50 nM) over 3 days led to an increase in cell number by approximately 1.7-fold. A similar outcome occurred for cells under hypoxic conditions, although the extent of cell growth was significantly less at around 1.3-fold. Furthermore, Bru prevented MG63 differentiation in response to co-treatment with the calcitriol analogue, EB1089, and the lipid growth factor, lysophosphatidic acid. The extent of inhibition was profound at approximately 2.8-fold. The application of the Nrf2 activator, dimethyl fumarate, did not rescue these phenotypes. Whilst Bru has shown promise in other cancer models, it would appear, from our findings, that this agent may not be suitable for the treatment of OS. Full article

Titanium and its alloys are widely used in biomedical implants due to their favorable mechanical properties and corrosion resistance; however, their natural surface lacks sufficient bioactivity and antibacterial performance. Micro-arc oxidation is a promising approach to producing bioactive coatings, and the incorporation of nanoparticles such as TiO₂ may further improve their functionality. This study aimed to determine the optimal TiO₂ nanoparticle concentration in the micro-arc oxidation electrolyte that ensures coating stability and biological safety. Calcium–phosphate coatings were fabricated on commercially pure titanium using micro-arc oxidation with two TiO₂ concentrations: 0.5 wt.% (MAO 1) and 1 wt.% (MAO 2). Surface morphology, porosity, and phase composition were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. Corrosion resistance was evaluated via potentiodynamic polarization in NaCl and Ringer’s solutions, while biocompatibility was assessed in vitro using HOS human osteosarcoma cells and MTT assays. Increasing the TiO₂ content to 1% decreased coating porosity (13.7% vs. 26.3% for MAO 1), enhanced corrosion protection, and reduced the friction coefficient compared to bare titanium. However, MAO 2 exhibited high cytotoxicity (81% cell death) and partial structural degradation in the biological medium. MAO 1 maintained integrity and showed no toxic effects (3% cell death). These results suggest that 0.5% TiO₂ is the optimal concentration, providing a balance between corrosion resistance, mechanical stability, and biocompatibility, supporting the development of safer implant coatings. Full article

Objective: This study aimed to elucidate the regulatory mechanisms of the long intergenic non-protein coding RNA 02381 (LINC02381)/microRNA-let-7g-5p (let-7g-5p)/thrombospondin 1 (THBS1) signaling axis in osteosarcoma (OS). Methods: The expression levels of LINC02381, let-7g-5p, and THBS1 were quantified in OS and adjacent normal tissues via reverse transcription quantitative polymerase chain reaction. Their correlations with clinicopathological features were analyzed. Expression patterns were further validated in OS cell lines (143B, U-2OS, Saos-2, MNNG-HOS, MG-63) and normal osteoblast cell line hFOB1.19. The molecular interaction between LINC02381 and let-7g-5p and the targeting relationship of let-7g-5p with THBS1 were verified via dual-luciferase reporter and RNA pull-down assays. Functional effects were assessed using cell counting kit-8, colony formation, Transwell migration, and xenograft tumor models. Results: Compared to adjacent normal tissues, LINC02381 and THBS1 were upregulated in OS tissues (fold change > 3.0, p < 0.001), while let-7g-5p was downregulated (fold change ≈ 0.038, p < 0.001). Similar expression trends were observed in U-2OS cells. Knockdown of LINC02381 or overexpression of let-7g-5p reduced cell proliferation, colony formation, migration, THBS1 expression, and tumor volume (p < 0.001). These inhibitory effects were partially reversed by let-7g-5p inhibitors, restoring cell viability and migration by approximately 70%. Mechanistically, LINC02381 functioned as a competing endogenous RNA (ceRNA), directly binding to let-7g-5p and mitigating its suppression of THBS1. Conclusions:LINC02381 promotes OA progression by acting as a ceRNA for let-7g-5p, thereby upregulating THBS1 expression. This signaling axis represents a potential therapeutic target for OS. Full article

Osteosarcoma (OS) is the most common bone-based cancer in both the US and the world in children, teenagers, and young adults. It is an aggressive form of sarcoma which forms mainly in the long bones of the legs and arms, often metastasizing prior to diagnosis. Every year across the globe, there are approximately 28,000 new cases, yet this sarcoma remains difficult to manage with standard treatments, partly due to its solid and immune resistant tumor microenvironment (TME). The quantity of research conducted on OS because of these difficulties has greatly increased over the past decade, meaning a comprehensive review of new findings on the TME may prove beneficial. This article aims to give a broad overview of the components of the TME of osteosarcoma, discuss its resistances and detrimental effects, and illustrate current and future immune therapy treatments which effectively target the microenvironment. Additionally, it will seek to highlight any knowledge gaps in the current literature and propose further studies to improve clinical outcomes. These studies could be beneficial in increasing drug and treatment efficacy for OS. Full article

A three year old male neutered mixed breed dog presented with a mass on the right carpus and accompanying lameness. A Jamshidi bone biopsy was performed, and histopathology results were consistent with a sarcoma. The dog received oncolytic virotherapy (OV) with vesicular stomatitis virus (VSV) as part of a clinical trial in dogs with osteosarcoma (OSA). Ten days after VSV treatment, the affected limb was amputated, and histopathology was consistent with intramedullary HSA. Considering the new diagnosis, standard doxorubicin chemotherapy was prescribed. With this combination of therapies, the dog had an extended survival of more than seven years and remains alive at the time of writing. This is the first case report documenting OV given in conjunction with the standard of care for canine appendicular HSA. Full article

Male infertility is a global health concern, and many cases are idiopathic in nature. The development and differentiation of germ cells (Gcs) are supported by Sertoli cells (Scs). Differentiated Scs support the development of Gcs into sperm, and hence, male fertility. We previously reported on a developmental switch in Scs around 12 days of age onwards in rats. During the process of the differentiation of Scs, the differential expression of mitophagy-related genes and its role in male fertility are poorly understood. To address this gap, we evaluated the microarray dataset GSE48795 to identify 12 mitophagy-related hub genes, including B-Cell Leukemia/Lymphoma 2 (Bcl2) and FBJ murine osteosarcoma viral oncogene homolog (Fos). We identify Neuron-derived orphan receptor 1 (Nor1) as a potential mitophagy-related gene of interest due to its strong regulatory association with two hub genes, Bcl2 and Fos, which were differentially expressed during Sc maturation. To validate this finding, we generated a transgenic rat model with the Sc-specific knockdown of Nor1 during puberty. A functional analysis showed impaired spermatogenesis with reduced fertility in these transgenic rats. Our findings suggest that Nor1 may be an important mitophagy-related gene regulating the function of Scs and thereby regulating male fertility. Full article

This study reports, for the first time, lanthanum oxide (La₂O₃) nanoparticles (NPs) that simultaneously suppress osteosarcoma MG63 cell proliferation and promote normal Vero cell viability, a dual effect not previously documented for La₂O₃ or similar metal oxide NPs. Physico-chemical characterization revealed a unique needle-like morphology, cubic crystallinity, and dispersion stability in DMSO without acidic dispersants, properties that can influence cellular uptake, ROS modulation, and biocompatibility. Comprehensive characterization (fluorescence spectroscopy, particle size/zeta potential, Raman, XRD, TGA, ATR-FTIR, and TEM) confirmed structural stability and surface chemistry relevant to biological interactions.La₂O₃ NPs exhibited broad-spectrum antibacterial activity (Gram-positive Streptococcus pyogenes, Bacillus cereus; Gram-negative Escherichia coli, Pseudomonas aeruginosa) and strong enzymatic/non-enzymatic antioxidant capacity, supporting potential use in implant coatings and infection control. MTT assays demonstrated dose-dependent cytotoxicity in MG63 cells, with enhanced proliferation in Vero cells. In zebrafish embryos, developmental toxicity assays yielded an LC₅₀ of 2.6 mg/mL higher (less toxic) than values reported for Ag NPs (~0.3–1 mg/mL) with normal development at lower concentrations and dose-dependent malformations (e.g., impaired somite formation and skeletal deformities) at higher doses. Collectively, these findings position La₂O₃ NPs as a multifunctional platform for oncology and regenerative medicine, uniquely combining selective anticancer activity, normal cell support, antimicrobial and antioxidant functions, and a defined developmental safety margin. Full article

Background: Sarcomas are a heterogeneous group of mesenchymal tumors frequently diagnosed in pediatric and young adult patients. These tumors respond poorly to conventional immunotherapy, although the precise reason for this is not known. We sought to characterize the systemic immune response to sarcomas by measuring the levels of circulating cytokines in the plasma of newly diagnosed sarcoma patients, testing the hypothesis that the nature of a patient’s immune response to their tumor directly affects outcome. Methods: Plasma was collected from newly diagnosed, treatment-naive pediatric sarcoma patients participating in an ongoing clinical trial, MCC20320. A panel of 18 cytokines was selected, and cytokine levels were measured using the Luminex platform. Cytokine levels were analyzed based on clinicopathological parameters such as gender, age, stage, and survival. Results: We found that the cytokine profile in patients newly diagnosed with sarcoma is distinct from healthy controls, but different sarcomas were not distinguishable. Patients with osteosarcoma who had elevated levels of multiple cytokines had inferior overall survival compared to those with fewer or no elevated levels. Similarly, elevated levels of individual cytokines and chemokines, including IL-24, CXCL5, and CXCL10, were associated with inferior event-free or overall survival in patients with osteosarcoma. Perhaps most significantly, elevated IL-1β at diagnosis was associated with metastatic presentation and inferior event-free survival in patients with osteosarcoma. Conclusions: These findings suggest that pediatric sarcoma patients mount a systemic immune response that may affect event-free or overall survival. IL-1β in particular may be a valuable therapeutic target for osteosarcoma patients. Full article

Osteosarcoma primarily occurs in children and adolescents, and is a highly aggressive bone tumor, particularly presenting challenges in metastatic or recurrent cases due to chemoresistance. Emerging evidences suggest that histone deacetylase inhibitors (HDACis) may exert anti-tumor effects by enhancing the efficacy of various therapeutic modalities. However, the combination of traditional chemotherapy with HDACi-based treatment for osteosarcoma intervention has not been thoroughly explored. This study investigates the anticancer properties of HDACis and/or etoposide (VP16) on the osteosarcoma cell lines U2OS and SJSA-1. Cell viability, morphology, growth and apoptosis were evaluated after treatments, in addition to their influence on the expression levels of proteins associated with apoptotic processes. To elucidate the underlying mechanisms, we employed RNA sequencing, RT-qPCR, and Western blot analyses. Treatment with either HDACis or VP16 alone resulted in an antiproliferative effects in U2OS and SJSA-1 cell lines. Notably, HDACis significantly increased the sensitivity of osteosarcoma cells to VP16, as evidenced by marked differences in cell viability, growth, morphology and apoptosis. Furthermore, when compared to doxorubicin treatment, this VP16/TSA/NAM combinatory regimen demonstrated a comparable ability to suppress cell viability while exhibiting a more pronounced inhibition of cell proliferation. Mechanistically, the combination of HDACis and VP16 specifically resulted in inhibition of the Hippo/YAP signaling cascade, accompanied by a reduction in total YAP1 protein expression. Collectively, our findings suggest that HDACis potentiate the capacity of VP16 to hinder cellular proliferation and trigger apoptosis via the downregulation of the Hippo/YAP pathway, thereby providing a prospective approach to overcome chemoresistance in osteosarcoma. Full article

Osteosarcoma (OS), the most common primary malignant bone tumor, arises in highly mechanosensitive tissue and exhibits marked heterogeneity and resistance to conventional therapies. While molecular drivers have been extensively characterized, the role of mechanical stimuli in OS progression remains underexplored. Here, we identify the transient receptor potential vanilloid 1 (TRPV1) channel as a key regulator of mechanotransduction and drug responsiveness in OS cells. Using uniaxial cyclic stretch, we show that aggressive U-2 OS cells undergo TRPV1-dependent perpendicular reorientation, unlike the inert SAOS-2 cells. Confocal microscopy, immunohistochemistry, and atomic force microscopy reveal that nanomolar concentrations of capsaicin—a well-characterized TRPV1 agonist—chemically mimic this mechanical phenotype, altering metastatic traits including adhesion, edge architecture, migration, nuclear-to-cytoplasmic ratio, and sensitivity to doxorubicin and cisplatin. TRPV1 activation, whether mechanical or chemical, induces subtype-specific effects absent in healthy hFOB osteoblasts. Notably, it differentially regulates nuclear localization of the proto-oncogene Src in U-2 OS versus SAOS-2 cells. Corresponding changes in Src and acetylated histone H3 (acH3) levels support a role for TRPV1 in modulating the Src–acH3 mechanosignaling axis. These effects are tumor-specific, positioning TRPV1 as a mechanosensitive signaling hub that integrates mechanical and chemical cues to drive epigenetic remodeling and phenotypic plasticity in OS, with potential as a therapeutic target in aggressive, drug-resistant subtypes Full article

Background: The progression of osteosarcoma is closely related to the immune microenvironment. Related studies have found that the RNA-binding motif protein, X-linked (RBMX), plays a regulatory role in modulating the biological characteristics of the tumor microenvironment (TME). However, its regulatory mechanism in osteosarcoma remains unclear. Methods: In this study, the expression of RBMX in osteosarcoma was analyzed using the results of bulk and single-cell transcriptome sequencing of human osteosarcoma. The RBMX knockout cell line was constructed via lentivirus transfection. The mouse subcutaneous implantable tumor model and single-cell transcriptome sequencing analysis revealed the effects of RBMX on the osteosarcoma microenvironment, as verified via multiplex immunofluorescence, flow cytometry, and PCR experiments. Results: Using the TARGET database and multiplex immunofluorescence, we found that RBMX is highly expressed in human osteosarcoma and is associated with poor prognosis. The high expression of RBMX may mediate the immunosuppressive microenvironment of human osteosarcoma. In vitro cell experiments showed that knockout of RBMX significantly inhibited the proliferation of mouse osteosarcoma cells. Through single-cell transcriptome sequencing analysis of subcutaneous implantable tumors in mice, we determined that RBMX deletion substantially elevated the recruitment of cytotoxic CD8⁺T cells within the mouse TME, which was further verified through flow cytometry analysis. Cell coculture assay confirmed that knockout of RBMX significantly enhanced the cytotoxic activity of CD8⁺T cells. Finally, cell communication and in vitro experimental verification revealed that knocking out RBMX might enhance the infiltration of CD8⁺T cells by upregulating histocompatibility 2, K1, and K region (H2-K1) and downregulating thrombospondin 1 (THBS1). Conclusions: This study may provide potential targets for reshaping the immune microenvironment of osteosarcoma and improving its therapeutic efficacy. Full article

Background: Osteosarcoma is an aggressive bone tumor with a high risk of lung metastasis, which severely affects patient survival. EMT plays a major role in tumor spread, therapy resistance, and cancer stemness. This review explores how EMT contributes to osteosarcoma metastasis and the underlying molecular mechanisms. Methods: We reviewed recent studies on EMT-related signaling pathways, transcription factors, and regulatory RNAs in osteosarcoma. We also examined the role of the tumor microenvironment. Results: EMT promotes cell detachment, migration, and lung colonization. Key pathways such as TGF-β, MAPK, PI3K/Akt, STAT3, Notch, and Wnt/β-catenin are involved. Non-coding RNAs further regulate EMT by interacting with these pathways. The tumor microenvironment, including hypoxia and immune cells, also supports EMT and metastasis. Conclusions: EMT is a key driver of metastasis and poor outcomes in osteosarcoma. Targeting EMT and its regulators may help prevent lung spread and improve treatment. Future strategies combining EMT inhibition with existing therapies could be promising for clinical application. Full article

Malignant bone and soft tissue tumors are often resistant to conventional treatment, and treatment options for unresectable and metastatic cases are limited. L-type amino acid transporter 1 (LAT1) is overexpressed in several malignancies, including sarcomas, making it an attractive target for targeted alpha therapy. In this study, we investigated the therapeutic efficacy of LAT1-targeted alpha therapy using a novel modified 3-astatin-211 Astato-α-methyl-L-tyrosine (²¹¹At-AAMT) for bone and soft tissue sarcomas. LAT1 expression and the specificity of LAT1-mediated uptake of ²¹¹At-AAMT were evaluated in bone and soft tissue sarcoma cell lines. Antiproliferative effects were assessed using cell viability and colony formation assays. DNA damage was assessed using immunostaining with phosphorylated histone γH2AX. In vivo efficacy of ²¹¹At-AAMT, determined using xenograft mouse models, was compared with that of doxorubicin. LAT1 was highly expressed in all cell lines, especially MP-CCS-SY and MG-63 cells. ²¹¹At-AAMT uptake was LAT1-dependent and significant in all cell lines. It inhibited cell proliferation in a dose-dependent manner, comparable to that of doxorubicin. In xenograft models, a single administration of ²¹¹At-AAMT significantly inhibited tumor growth without systemic toxicity, whereas doxorubicin caused weight loss. Histopathological analysis showed reduced cell density, inhibited proliferation, and extensive DNA damage in tumors treated with ²¹¹At-AAMT, whereas LAT1 expression was maintained in residual tumor tissues. LAT1-targeted alpha therapy with ²¹¹At-AAMT demonstrated antitumor efficacy comparable to that of first-line chemotherapy for osteosarcoma and soft tissue sarcoma. Sustained LAT1 expression suggests the potential for repeated or combination treatments, highlighting its promise as a novel therapy for advanced, treatment-resistant sarcomas. Full article

Background: Osteosarcoma (OS) is the most commonly occurring type of bone cancer in both humans and canines. The survival outcomes for OS patients have not improved significantly in decades. A novel and innovative treatment option that is currently under investigation for OS in the veterinary field is the focused ultrasound ablation modality, histotripsy. Histotripsy is a non-thermal, non-invasive, non-ionizing ablation modality that destroys tissue through generation of acoustic cavitation. Objective: In the current study, we sought to investigate the utility of an orthotropic OS xenograft murine model for characterization of chronic ablative and clinical outcomes post-histotripsy ablation. Method: Given the high comparative relevance of canine to human OS, histotripsy was delivered to orthotopic OS tumors in both human and canine xenograft murine models. Results: Histotripsy improved limb function in tumor-bearing mice compared to untreated tumor bearing mice. The results of this study demonstrated the utility of the orthotopic OS xenograft murine model for histotripsy-based preclinical studies. Conclusions: The current study is the first published investigation for the use of an orthotopic xenograft murine model for the development of histotripsy ablation for OS. The developmental process of the model, technical limitations, and future directions are discussed. Full article