hsa_circ_0020378 regulating miR-339-3p/COL1A1 promotes osteosarcoma progression

Osteosarcoma is a malignant orthopedic tumor that is frequently diagnosed in the pediatric population. Several studies have summarized the functions of circular RNAs (circRNAs) in the progression of osteosarcoma. This study aimed to investigate a novel circRNA, hsa_circ_0020378 (circ_0020378), and elucidate its functions and underlying mechanisms during osteosarcoma progression. The expression levels of circ_0020378, miR-339-3p, and COL1A1 in osteosarcoma cells and tissues were determined using RT-qPCR or Western blotting. CCK8, transwell migration, colony formation, and xenograft experiments were performed to assess the malignancy of osteosarcoma cells. Luciferase and RNA immunoprecipitation (RIP) experiments were employed to validate the interactions of miR-339-3p with circ_0020378 and COL1A1 3'UTR. Osteosarcoma cells and tissues showed significant upregulation of circ_0020378 and COL1A1 and downregulation of miR-339-3p. Silencing circ_0020378 in osteosarcoma cells inhibited their proliferation, colony formation, and migration. The inhibitive influence of circ_0020378 silencing during osteosarcoma tumorigenesis in vitro was verified in vivo. Circ_0020378 sponged miR-339-3p which targeted COL1A1 3'UTR. Circ _0020378 silencing disrupted the tumor-promoting effect of the miR-339-3p inhibitor in osteosarcoma cells. Furthermore, miR-339-3p inhibitor attenuated the suppressive effect of COL1A1 downregulation on malignant osteosarcoma cell phenotypes. Circ_0020378 stimulates osteosarcoma progression by downregulating miR-339-3p/COL1A1 expression. These findings provide a theoretical basis for the discovery of novel osteosarcoma targets.

Clinical and therapeutical significances of the cluster and signature based on oxidative stress for osteosarcoma

BACKGROUND

It is of great clinical significance to find out the ideal tumor biomarkers and therapeutic targets to improve the prognosis of patients with osteosarcoma (OS). Oxidative stress (OXS) can directly target intracellular macromolecules and exhibit dual effects of tumor promotion and suppression.

METHODS

OXS-related genes (OXRGs) were extracted from public databases, including TARGET and GEO. Univariate Cox regression analysis, Random Survival Forest algorithm, and LASSO regression were performed to identify prognostic genes and establish the OXS-signature. The efficacy of the OXS-signature was further evaluated by Kaplan-Meier curves and timeROC package. Evaluation of immunological characteristics was achieved based on ESTIMATE algorithm and ssGSEA. Submap algorithm was used to explore the response to anti-PD1 and anti-CTLA4 therapy for OS. Drug response prediction was conducted by using pRRophetic package. The expression values of related genes in the OXS-signature were detected with PCR assays.

RESULTS

Two OXS-clusters were identified for OS, with remarkable differences of clusters presented in prognosis. Kyoto Encyclopedia of Genes Genomes (KEGG) analysis showed that differentially expressed genes (DEGs) between the OXS-clusters were significantly enriched in several immune-related pathways. Patients with lower OS-scores attained better clinical outcomes, and presented more sensitivity to ICB therapy. By contrast, OS patients with higher OS-scores revealed more sensitivity to certain drugs. Furthermore, critical genes, RHBDL2 and CGREF1 from the model, were significantly higher expressed in OS cell lines.

CONCLUSIONS

Our study identified the clusters and signature based on OXS, which would lay the foundation for molecular experimental research, disease prevention and treatment of OS.

Enhanced Biomimetics of Three-Dimensional Osteosarcoma Models: A Scoping Review

This scoping review evaluated 3D osteosarcoma (OS) models' biomimicry, examining their ability to mimic the tumour microenvironment (TME) and their drug sensitivity. Adhering to PRISMA-ScR guidelines, the systematic search revealed 293 studies, with 70 selected for final analysis. Overall, 64% of 3D OS models were scaffold-based, compared to self-generated spheroid models. Scaffolds generated using native matrix were most common (42%) with collagen I/hydroxyapatite predominating. Both scaffold-based and scaffold-free models were used equally for drug screening. The sensitivity of cancer cells in 3D was reported to be lower than that of cells in 2D in ~90% of the drug screening studies. This correlates with the observed upregulation of drug resistance. OS cells cultured in extracellular matrix (ECM)-mimetic scaffolds and native biomaterials were more resistant than cells in 2D. Co-cultures of OS and stromal cells in 3D models enhanced osteogenic differentiation, ECM remodelling, mineralisation, and angiogenesis, suggesting that tumour-stroma crosstalk promotes disease progression. Seven studies demonstrated selective toxicity of chemotherapeutics towards OS cells while sparing stromal cells, providing useful evidence for developing biomimetic tumour-stroma models to test selective drug toxicity. In conclusion, this review highlights the need to enhance biomimicry in 3D OS models for TME recapitulation, especially in testing novel therapeutics. Future research should explore innovative 3D biomimetic models, biomaterials, and advancements in personalised medicine.

PROGNOSTIC IMPLICATIONS OF PD-L1 EXPRESSION AND LOSS OF PTEN IN PATIENTS WITH RHABDOMYOSARCOMA, EWING'S SARCOMA AND OSTEOSARCOMA

BACKGROUND

In children, osteosarcoma (OS), Ewing's sarcoma (ES), and rhabdomyosarcoma (RMS) are the most common sarcomas. A link between the anti-programmed death ligand-1 PD-L1 and the tumor suppressor phosphatase and tensin homologue (PTEN) expression has been described in many tumors. The aim of this work is to determine clinicopathological relationships and the possible prognostic significance of PD-L1 and PTEN expression in rhabdomyosarcoma (RMS), Ewing's sarcoma (ES), and osteosarcoma (OS).

MATERIALS AND METHODS

Expression of PD-L1 and PTEN were examined by immunohistochemistry in 45 archival RMS, ES, and OS cases.

RESULTS

The positive expression of PD-L1 was found in 16.7% and 31.6% of ES and OS, respectively. The negative PD-L1 was related to a substantially longer survival in ES cases (p = 0.045), but positive PD-L1 expression was significantly associated with the increased tumor stage and vascular invasion in the OS cases (p = 0.005 and p = 0.002), respectively. On the other hand, PTEN loss was strongly associated with deep tumor, high tumor grade, and recurrence in RMS (p = 0.002, p = 0.045, and p = 0.026, respectively). However, PTEN loss was significantly absent in ES as tumor grade increased (p = 0.031). It is noteworthy that tumor recurrence, the loss of PTEN, and positive PD-L1 were all considered predictive factors in OS patients (p = 0.045, p = 0.032, and p = 0.02, respectively).

CONCLUSIONS

In children, OS and ES have positive PD-L1 expression, which has an independent unfavorable prognostic effect and raises the possibility of using PD-L1 as a therapeutic target. OS, ES, and RMS prognosis are all predicted by PTEN loss.

The Warburg Trap: A Novel Therapeutic Approach for Targeting Osteosarcoma

Although urgently needed, no significant improvements in osteosarcoma (OS) therapy have been achieved within the last decades. Here, we present a new therapeutic approach based on drug combinations consisting of mitochondrial complex I (MCI) inhibitors and ionophores that induce cancer cell-specific cell death based on a modulation of cellular energy metabolism and intracellular pH (pHi) named the Warburg Trap (WT). The effects of several drug combinations on intracellular pH, cell viability, colony-forming capacity and expression of WNT-target genes were analysed using OS cell lines and primary human osteoblasts (HOB). Tumour take rates and tumour volumes were analysed in vivo using a chicken chorioallantoic membrane assay (CAM). Several WT drug combinations induced the intracellular acidification and apoptotic cell death in OS cells, whereas HOBs tolerated the treatment. A significant inhibition of the colony-forming ability of OS cells and downregulation of WNT-target genes suggest that cancer stem cells (CSCs) are also targeted by the WT approach. In vivo, we observed a significant reduction in the tumour take rates in response to WT drug treatment. Our data suggest that the Warburg Trap is a promising approach for the development of a novel and effective OS therapy to replace or supplement the current OS chemotherapy.

Current status and future challenges of CAR-T cell therapy for osteosarcoma

Osteosarcoma, the most common bone malignancy in children and adolescents, poses considerable challenges in terms of prognosis, especially for patients with metastatic or recurrent disease. While surgical intervention and adjuvant chemotherapy have improved survival rates, limitations such as impractical tumor removal or chemotherapy resistance hinder the treatment outcomes. Chimeric antigen receptor (CAR)-T cell therapy, an innovative immunotherapy approach that involves targeting tumor antigens and releasing immune factors, has shown significant advancements in the treatment of hematological malignancies. However, its application in solid tumors, including osteosarcoma, is constrained by factors such as low antigen specificity, limited persistence, and the complex tumor microenvironment. Research on osteosarcoma is ongoing, and some targets have shown promising results in pre-clinical studies. This review summarizes the current status of research on CAR-T cell therapy for osteosarcoma by compiling recent literature. It also proposes future research directions to enhance the treatment of osteosarcoma.

ctDNA quantification improves estimation of outcomes in patients with high-grade osteosarcoma: a translational study from the OS2006 trial

BACKGROUND

Osteosarcoma stratification relies on clinical parameters and histological response. We developed a new personalized stratification using less invasive circulating tumor DNA (ctDNA) quantification.

PATIENTS AND METHODS

Plasma from patients homogeneously treated in the prospective protocol OS2006, at diagnosis, before surgery and end of treatment, were sequenced using low-passage whole-genome sequencing (lpWGS) for copy number alteration detection. We developed a prediction tool including ctDNA quantification and known clinical parameters to estimate patients' individual risk of event.

RESULTS

ctDNA quantification at diagnosis (diagCPA) was evaluated for 183 patients of the protocol OS2006. diagCPA as a continuous variable was a major prognostic factor, independent of other clinical parameters, including metastatic status [diagCPA hazard ratio (HR) = 3.5, P = 0.002 and 3.51, P = 0.012, for progression-free survival (PFS) and overall survival (OS)]. At the time of surgery and until the end of treatment, diagCPA was also a major prognostic factor independent of histological response (diagCPA HR = 9.2, P < 0.001 and 11.6, P < 0.001, for PFS and OS). Therefore, the addition of diagCPA to metastatic status at diagnosis or poor histological response after surgery improved the prognostic stratification of patients with osteosarcoma. We developed the prediction tool PRONOS to generate individual risk estimations, showing great performance ctDNA quantification at the time of surgery and the end of treatment still required improvement to overcome the low sensitivity of lpWGS and to enable the follow-up of disease progression.

CONCLUSIONS

The addition of ctDNA quantification to known risk factors improves the estimation of prognosis calculated by our prediction tool PRONOS. To confirm its value, an external validation in the Sarcoma 13 trial is underway.

Establishment and Characterization of Cell Lines from Canine Metastatic Osteosarcoma

Despite the advancements in treatments for other cancers, the outcomes for osteosarcoma (OSA) patients have not improved in the past forty years, especially in metastatic patients. Moreover, the major cause of death in OSA patients is due to metastatic lesions. In the current study, we report on the establishment of three cell lines derived from metastatic canine OSA patients and their transcriptome as compared to normal canine osteoblasts. All the OSA cell lines displayed significant upregulation of genes in the epithelial mesenchymal transition (EMT) pathway, and upregulation of key cytokines such as CXCL8, CXCL10 and IL6. The two most upregulated genes are MX1 and ISG15. Interestingly, ISG15 has recently been identified as a potential therapeutic target for OSA. In addition, there is notable downregulation of cell cycle control genes, including CDKN2A, CDKN2B and THBS1. At the protein level, p16INK4A, coded by CDKN2A, was undetectable in all the canine OSA cell lines, while expression of the tumor suppressor PTEN was variable, with one cell line showing complete absence and others showing low levels of expression. In addition, the cells express a variety of actionable genes, including KIT, ERBB2, VEGF and immune checkpoint genes. These findings, similar to those reported in human OSA, point to some genes that can be used for prognosis, targeted therapies and novel drug development for both canine and human OSA patients.

Neoadjuvant systemic oncolytic vesicular stomatitis virus is safe and may enhance long-term survivorship in dogs with naturally occurring osteosarcoma

Osteosarcoma is a devastating bone cancer that disproportionally afflicts children, adolescents, and young adults. Standard therapy includes surgical tumor resection combined with multiagent chemotherapy, but many patients still suffer from metastatic disease progression. Neoadjuvant systemic oncolytic virus (OV) therapy has the potential to improve clinical outcomes by targeting primary and metastatic tumor sites and inducing durable antitumor immune responses. Here we describe the first evaluation of neoadjuvant systemic therapy with a clinical-stage recombinant oncolytic vesicular stomatitis virus (VSV), VSV-IFNβ-NIS, in naturally occurring cancer, specifically appendicular osteosarcoma in companion dogs. Canine osteosarcoma has a similar natural disease history as its human counterpart. VSV-IFNβ-NIS was administered prior to standard of care surgical resection, permitting microscopic and genomic analysis of tumors. Treatment was well-tolerated and a "tail" of long-term survivors (∼35%) was apparent in the VSV-treated group, a greater proportion than observed in two contemporary control cohorts. An increase in tumor inflammation was observed in VSV-treated tumors and RNA-seq analysis showed that all the long-term responders had increased expression of a T cell anchored immune gene cluster. We conclude that neoadjuvant VSV-IFNβ-NIS is safe and may increase long-term survivorship in dogs with naturally occurring osteosarcoma, particularly those that exhibit pre-existing antitumor immunity.

Novel combination of imipridones and histone deacetylase inhibitors demonstrate cytotoxic effect through integrated stress response in pediatric solid tumors

There is a demonstrated need for new chemotherapy options in pediatric oncology, as pediatric solid tumors continue to plateau at 60% with event-free survival. Imipridones, a novel class of small molecules, represent a potential new therapeutic option, with promising pre-clinical data and emerging clinical trial data in adult malignancies. ONC201, ONC206, and ONC212 are imipridones showing pro-apoptotic anti-cancer response. Using cell viability assays, and protein immunoblotting, we were able to demonstrate single-agent efficacy of all 3 imipridones inducing cell death in pediatric solid tumor cell lines, including osteosarcoma, malignant peripheral nerve sheath tumors, Ewing sarcoma (EWS), and neuroblastoma. ONC201 displayed IC50 values for non-H3K27M-mutated EWS cell lines ranging from 0.86 µM (SK-N-MC) to 2.76 µM (RD-ES), which were comparable to the range of IC50 values for H3K27M-mutated DIPG cells lines (range 1.06 to 1.56 µM). ONC212 demonstrated the highest potency in single-agent cell killing, followed by ONC206, and ONC201. Additionally, pediatric solid tumor cells were treated with single-agent therapy with histone deacetylase inhibitors (HDACi) vorinostat, entinostat, and panobinostat, showing cell killing with all 3 HDACi drugs, with panobinostat showing the greatest potency. We demonstrate that dual-agent therapy with combinations of imipridones and HDACi lead to synergistic cell killing and apoptosis in all pediatric solid tumor cell lines tested, with ONC212 and panobinostat combinations demonstrating maximal potency. The imipridones induced the integrated stress response with ATF4 and TRAIL receptor upregulation, as well as reduced expression of ClpX. Hyperacetylation of H3K27 was associated with synergistic killing of tumor cells following exposure to imipridone plus HDAC inhibitor therapies. Our results introduce a novel class of small molecules to treat pediatric solid tumors in a precision medicine framework. Use of impridones in pediatric oncology is novel and shows promising pre-clinical efficacy in pediatric solid tumors, including in combination with HDAC inhibitors.

Exploring the immune microenvironment of osteosarcoma through T cell exhaustion-associated gene expression: a study on prognosis prediction

Background

Osteosarcoma is a highly aggressive type of bone cancer with a poor prognosis. In the tumor immune microenvironment, T-cell exhaustion can occur due to various factors, leading to reduced tumor-killing ability. The purpose of this study was to construct a prognostic model based on T-cell exhaustion-associated genes in osteosarcoma.

Methods

Patient data for osteosarcoma were retrieved from the TARGET and GEO databases. Consensus clustering was employed to identify two novel molecular subgroups. The dissimilarities in the tumor immune microenvironment between these subgroups were evaluated using the "xCell" algorithm. GO and KEGG analyses were conducted to elucidate the underlying mechanisms of gene expression. Predictive risk models were constructed using the least absolute shrinkage and selection operator algorithm and Cox regression analysis. To validate the prognostic significance of the risk gene expression model at the protein level, immunohistochemistry assays were performed on osteosarcoma patient samples. Subsequently, functional analysis of the key risk gene was carried out through in vitro experimentation.

Results

Four gene expression signatures (PLEKHO2, GBP2, MPP1, and VSIG4) linked to osteosarcoma prognosis were identified within the TARGET-osteosarcoma cohort, categorizing patients into two subgroups. The resulting prognostic model showed strong predictive capability, with area under the receiver operating characteristic curve (AUC) values of 0.728/0.740, 0.781/0.658, and 0.788/0.642 for 1, 3, and 5-year survival in both training and validation datasets. Notably, patients in the low-risk group had significantly higher stromal, immune, and ESTIMATE scores compared to high-risk counterparts. Additionally, a nomogram was developed, exhibiting high accuracy in predicting the survival outcome of osteosarcoma patients. Immunohistochemistry, Kaplan-Meier, and time-dependent AUC analyses consistently supported the prognostic value of the risk model within our osteosarcoma patient cohort. In vitro experiments provided additional validation by demonstrating that the downregulation of GBP2 promoted the proliferation, migration, and invasion of osteosarcoma cells while inhibiting apoptosis.

Conclusion

The current study established a prognostic signature associated with TEX-related genes and elucidated the impact of the pivotal gene GBP2 on osteosarcoma cells via in vitro experiments. Consequently, it introduces a fresh outlook for clinical prognosis prediction and sets the groundwork for targeted therapy investigations in osteosarcoma.

Time-Sequential and Multi-Functional 3D Printed MgO2 /PLGA Scaffold Developed as a Novel Biodegradable and Bioactive Bone Substitute for Challenging Postsurgical Osteosarcoma Treatment

Osteosarcoma (OS) is the most commonly occurring primary bone malignant tumor. The clinical postsurgical OS treatment faces big challenges for the staged therapeutic requirements of early anti-tumor, anti-bacterial, and long-lasting osteogenesis. Herein, multi-functional bioactive scaffolds with time-sequential functions of preventing tumor recurrence, inhibiting bacterial infection, and promoting bone defect repair are designed as a novel strategy. Nanocomposite scaffold magnesium peroxide (MgO2 )/poly (lactide-co-glycolide) is prepared by low-temperature 3D printing for controllable releasing magnesium ions (Mg2+ ) and reactive oxygen species in a time-sequential manner. The scaffold with 20 wt% MgO2 (20MP) is verified with desired mechanical properties, as well as exhibits staged release behavior of bioactive elements with hydrogen peroxide (H2 O2 ) release for the first 3 weeks, and long-lasting Mg2+ release for 12 weeks. The released H2 O2 initiates chemodynamic therapy to induce apoptosis and ferroptosis in tumor cells, along with activating the anticancer immune microenvironment by M1 polarization of macrophages. The released Mg2+ subsequently enhances bone repair by activating the Wnt3a/GSK-3β/β-catenin signaling pathway to promote osteogenic differentiation of bone marrow mesenchymal stem cells and create osteopromotive immune microenvironment by M2 polarization of macrophages. In conclusion, the multi-functional 20MP scaffold demonstrates time-sequential therapeutic properties as an innovative strategy for OS-associated bone defect treatment.

MMP-2 regulates Src activation via repression of the CHK/MATK tumor suppressor in osteosarcoma

BACKGROUND

Doxorubicin, a first-line anticancer drug for osteosarcoma treatment, has been the subject of recent research exploring the mechanisms behind its chemoresistance and its ability to enhance cell migration at sublethal concentrations. Matrix metalloproteinase-2 (MMP-2), a type IV collagenase and zinc-dependent endopeptidase, is well-known for degrading the extracellular matrix and promoting cancer metastasis. Our previous work demonstrated that nuclear MMP-2 regulates ribosomal RNA transcription via histone clipping, thereby controlling gene expression. Additionally, MMP-2 activity is regulated by the non-receptor tyrosine kinase and oncogene, Src, which plays a crucial role in cell adhesion, invasion, and metastasis. Src kinase is primarily regulated by two endogenous inhibitors: C-terminal Src kinase (Csk) and Csk homologous kinase (CHK/MATK).

AIM

In this study, we reveal that the MMP-2 gene acts as an upstream regulator of Src kinase activity by suppressing its endogenous inhibitor, CHK/MATK, in osteosarcoma cells.

METHODS AND RESULTS

We show that enhanced osteosarcoma cell migration which is induced by sublethal concentrations of doxorubicin can be overcome by inactivating the MMP-2 gene or overexpressing CHK/MATK. Our findings highlight the MMP-2 gene as a promising additional target for combating cancer cell migration and metastasis. This is due to its role in suppressing on the gene and protein expression of the tumor suppressor CHK/MATK in osteosarcoma.

CONCLUSION

By targeting the MMP-2 gene, we can potentially enhance the effectiveness of doxorubicin treatment and reduce chemoresistance in osteosarcoma.

Highly Biocompatible Polyester-Based Piezoelectric Elastomer with Antitumor and Antibacterial Activity for Ultrasound-Enhanced Piezoelectric Therapy

Currently, the use of piezoelectric materials to provide sustainable and noninvasive bioelectric stimulation to eradicate tumor cells and accelerate wound healing has raised wide attention. The development of a multifunctional piezoelectric elastomer with the ability to perform in situ tumor therapy as well as wound repair is of paramount importance. However, current piezoelectric materials have a large elastic modulus and limited stretchability, making it difficult to match with the dynamic curvature changes of the wound. Therefore, by copolymerizing lactic acid, butanediol, sebacic acid, and itaconic acid to develop a piezoelectric elastomer (PLBSIE), we construct a new ultrasound-activated PLBSIE-based tumor/wound unified therapeutic platform. Excitedly, it showed outstanding piezoelectric performance and high stretchability, and the separated carrier could react with water to generate highly cytotoxic reactive oxygen species (ROS), contributing to effectively killing tumor cells and eliminating bacteria through piezoelectric therapy. In addition, ultrasound-triggered piezoelectric effects could promote the migration and differentiation of wound-healing-related cells, thus accelerating wound healing. Herein, such a piezoelectric elastomer exerted a critical role in postoperative tumor-induced wound therapy and healing with the merits of possessing multifunctional abilities. Taken together, the developed ultrasound-activated PLBSIE will offer a comprehensive treatment for postoperative osteosarcoma therapy.

Patterns of metastatic progression and association with clinical outcomes in canine osteosarcoma: A necropsy study of 83 dogs

Osteosarcoma is a highly metastatic primary bone tumour that occurs spontaneously in both pet dogs and humans. Patterns of metastasis to organs beyond the most common site (lung) are poorly characterised and it is unknown whether specific associations between patterns of metastatic progression and patient features exist. This retrospective study characterised the necropsy findings of 83 dogs receiving standardised therapy and clinical monitoring in a prospective clinical trial setting to document patterns of metastasis and correlate outcomes with these patterns and other patient and tumour-specific factors. A total of 20 different sites of metastasis were documented, with lung as the most common site, followed by bone, kidney, liver, and heart. Two distinct clusters of dogs were identified based on patterns of metastasis. There was no significant association between site of enrollment, trial arm, sex, serum alkaline phosphatase (ALP) activity, or tumour location and clinical outcomes. A second cancer type was identified at necropsy in 10 dogs (10/83; 12%). These data showcase the extensive nature of osteosarcoma metastasis beyond the lung and provide a benchmark for clinical monitoring of the disease. Further, this study provides insight into transcriptional features of primary tumours that may relate to a propensity for osteosarcoma metastasis to specific organs and tissues.

CRISPR-Cas9 screening identified lethal genes enriched in necroptosis pathway and of prognosis significance in osteosarcoma

BACKGROUND

The present study aimed to identify indispensable genes associated with tumor cell viability according to the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) datasets, which may support new therapeutic targets for patients with osteosarcoma.

METHODS

The transcriptome patterns between tumor and normal tissues, which were obtained from the Therapeutically Applicable Research to Generate Effective Treatments dataset, were overlapped with the genomics associated with cell viability screened by CRISPR-Cas9 technology. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses were employed to determine enrichment pathways related to lethal genes. Least absolute shrinkage and selection operator (LASSO) regression was employed to construct a risk model related to lethal genes for predicting clinical outcomes of osteosarcoma. Univariate and multivariate Cox regressions were conducted to assess the prognostic value of this feature. Weighted gene co-expression network analysis was performed to identify modules associated with patients with high-risk score.

RESULTS

In total, 34 lethal genes were identified in this investigation. These genes were enriched in the necroptosis pathway. The risk model based on LASSO regression algorithm distinguishes patients with high-risk score from patients with low-risk score. Compared with low-risk patients, high-risk patients showed a shorter overall survival rate in both the training and validation sets. The time-dependent receiver operating characteristic curves of 1, 3 and 5 years displayed that the risk score has great prediction performance. The necroptosis pathway represents the main difference in biological behavior between the high-risk group and the low-risk group. Meanwhile, CDK6 and SMARCB1 may serve as important targets for detecting osteosarcoma progression.

CONCLUSIONS

The present study developed a predictive model that outperformed classical clinicopathological parameters for predicting the clinical outcomes of osteosarcoma patients and identified specific lethal genes, including CDK6 and SMARCB1, as well as the necroptosis pathway. These findings may serve as potential targets for future osteosarcoma treatments.

Hub biomarkers in ultrasound-guided bladder cancer and osteosarcoma: Myosin light chain kinase and caldesmon

Bladder cancer and osteosarcoma are 2 types of cancers that originate from epithelial tissues inside the bladder and bone or muscle tissues. Ultrasound-guided biopsies provide crucial support for the diagnosis and treatment of bladder cancer and osteosarcoma. However, the relationship between myosin light chain kinase (MYLK) and caldesmon (CALD1) and bladder cancer and osteosarcoma remains unclear. The bladder cancer datasets GSE65635 and GSE100926, the osteosarcoma dataset GSE39058, were obtained from gene expression omnibus. Differentially expressed genes (DEGs) were screened and weighted gene co-expression network analysis was performed. The construction and analysis of protein-protein interaction network, functional enrichment analysis, gene set enrichment analysis. Gene expression heat map was drawn and immune infiltration analysis was performed. The comparative toxicogenomics database analysis were performed to find disease most related to core gene. Western blotting experiments were performed. TargetScan screened miRNAs that regulated central DEGs. We obtained 54 DEGs. Functional enrichment analysis revealed significant enrichment in terms of cellular differentiation, cartilage development, skeletal development, muscle actin cytoskeleton, actin filament, Rho GTPase binding, DNA binding, fibroblast binding, MAPK signaling pathway, apoptosis, and cancer pathways. Gene set enrichment analysis indicated that DEGs were primarily enriched in terms of skeletal development, cartilage development, muscle actin cytoskeleton, MAPK signaling pathway, and apoptosis. The immune infiltration analysis showed that when T cells regulatory were highly expressed, Eosinophils exhibited a similar high expression, suggesting a strong positive correlation between T cells regulatory and Eosinophils, which might influence the disease progression in osteosarcoma. We identified 6 core genes (SRF, CTSK, MYLK, VCAN, MEF2C, CALD1). MYLK and CALD1 were significantly correlated with survival rate and exhibited lower expression in bladder cancer and osteosarcoma samples compared to normal samples. Comparative toxicogenomics database analysis results indicated associations of core genes with osteosarcoma, bladder tumors, bladder diseases, tumors, inflammation, and necrosis. The results of Western blotting showed that the expression levels of MYLK and CALD1 in bladder cancer and osteosarcoma were lower than those in normal tissues. MYLK and CALD1 likely play a role in regulating muscle contraction and smooth muscle function in bladder cancer and osteosarcoma. The lower expression of MYLK and CALD1 is associated with poorer prognosis.

[Retracted] Expression and function of PIM kinases in osteosarcoma

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that (in addition to overlapping data panels internally within the figure, suggesting that some of the data had been derived from the same original sources where the results of differently performed experiments were intended to have been portrayed) certain of the data featured in Fig. 5A on p. 2123 had already been published in another article written by different authors at different research institutes [Tian F, Ding D and Li D: Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells. Int J Oncol 46: 2355‑2363, 2015]. Owing to the fact that the contentious data in the above article had already been published prior to its submission to International Journal of Oncology, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Oncology 49: 2116‑2126, 2016; DOI: 10.3892/ijo.2016.3708].

Assessment of the added value of intravenous gadolinium for knee osteosarcoma resection planning in pediatric and young adult patients

BACKGROUND AND OBJECTIVES

To assess the impact of Gadolinium-enhanced magnetic resonance imaging (MRI) sequences on Preoperative imaging evaluation and surgical planning parameters for osteosarcoma (OS) of the knee in pediatric and young adult patients.

METHODS

Thirty MRI scans of patients with OS about the knee were reviewed by five orthopedic oncologists. Key preoperative parameters (neurovascular bundle involvement, intra-articular tumor extension, extent of intramedullary extension) and surgical plans were evaluated based on non-contrast versus Gd contrast enhanced sequences. Assessment agreement, inter-rater agreement, and intrarater agreement between pre and postcontrast images were evaluated via Kappa statistics.

RESULTS

Moderate agreement was seen between non and contrast-enhanced assessment of neurovascular involvement and intra-articular tumor extension. Intrarater reproducibility was substantial for neurovascular bundle involvement (precontrast Kappa: 0.63, postcontrast Kappa: 0.69). Intrarater reproducibility was also substantial for precontrast (Kappa: 0.70) and moderate for postcontrast (Kappa: 0.50) assessment of intra-articular tumor extension. Planned resection length and choice of surgical approach were similar between sequences. The addition of Gd-enhanced sequences improved the inter-rater agreement across collected parameters.

CONCLUSIONS

While some findings suggest that contrast enhanced sequences may not significantly alter the assessment of key preoperative planning parameters by orthopedic oncologists, they may help reduce variability among providers with differing experience levels.

Rehabilitation Following Above-Knee Amputation in a Pediatric Osteosarcoma Patient: A Case Report

The earliest stages of osteosarcomas are primitive mesenchymal cells. It generally occurs close to the long bones' metaphysis and typically affects the long bones, such as the arm and leg. This case report underscores the pivotal role of physiotherapy in the rehabilitation of a 14-year-old male diagnosed with osteosarcoma, who underwent above-knee amputation. The structured six-week rehabilitation program, encompassing passive, active-assisted, and active exercises for the affected limb, alongside strength training for unaffected joints, produced notable gains in the pain rating scale and the lower-extremity functional scale in just 15 days. These outcomes underscore the significance of early and targeted physiotherapy interventions in optimizing functional outcomes and quality of life for young patients with osteosarcoma after surgery.

The second-generation curcumin analogue RL71 elicits G2/M cell cycle arrest and apoptosis in canine osteosarcoma cells

Canine osteosarcoma is an aggressive cancer, comprising 85% of canine bone neoplasms. Current treatment practices of surgery and chemotherapy increase 1-year survival by only 45%. The curcumin analogue RL71, has demonstrated potent in vitro and in vivo efficacy in several models of human breast cancer through increased apoptosis and cell cycle arrest. Thus, the present study aimed to investigate efficacy of curcumin analogues in two canine osteosarcoma cell lines. Osteosarcoma cell viability was assessed using the sulforhodamine B assay and mechanisms of action were determined by analysing the levels of cell cycle and apoptotic regulatory proteins via Western blotting. Further evidence was obtained using flow cytometry to detect cell cycle distribution and the number of apoptotic cells. RL71 was the most potent curcumin analogue with EC50 values of 0.64 ± 0.04 and 0.38 ± 0.009 μM (n = 3) in D-17 (commercial) and Gracie canine osteosarcoma cells, respectively. RL71 significantly increased the ratio of cleaved-caspase 3 to pro-caspase 3 and the level of apoptotic cells at the 2× and 5× EC50 concentration (p < 0.001, n = 3). Furthermore, at the same concentration, RL71 significantly increased the number of cells in the G2/M phase. In conclusion, RL71 has potent cytotoxic activity in canine osteosarcoma cells triggering G2/M arrest and apoptosis at concentrations achievable in vivo. Future research should further investigate molecular mechanisms for these changes in other canine osteosarcoma cell lines prior to in vivo investigation.

Sanguinarine induces apoptosis in osteosarcoma by attenuating the binding of STAT3 to the single-stranded DNA-binding protein 1 (SSBP1) promoter region

BACKGROUND AND PURPOSE

Osteosarcoma, a primary malignant bone tumour prevalent among adolescents and young adults, remains a considerable challenge despite protracted progress made in enhancing patient survival rates over the last 40 years. Consequently, the development of novel therapeutic approaches for osteosarcoma is imperative. Sanguinarine (SNG), a compound with demonstrated potent anticancer properties against various malignancies, presents a promising avenue for exploration. Nevertheless, the intricate molecular mechanisms underpinning SNG's actions in osteosarcoma remain elusive, necessitating further elucidation.

EXPERIMENTAL APPROACH

Single-stranded DNA-binding protein 1 (SSBP1) was screened out by differential proteomic analysis. Apoptosis, cell cycle, reactive oxygen species (ROS) and mitochondrial changes were assessed via flow cytometry. Western blotting and quantitative real-time reverse transcription PCR (qRT-PCR) were used to determine protein and gene levels. The antitumour mechanism of SNG was explored at a molecular level using chromatin immunoprecipitation (ChIP) and dual luciferase reporter plasmids.

KEY RESULTS

Our investigation revealed that SNG exerted an up-regulated effect on SSBP1, disrupting mitochondrial function and inducing apoptosis. In-depth analysis uncovered a mechanism whereby SNG hindered the JAK/signal transducer and activator of transcription 3 (STAT3) signalling pathway, relieved the inhibitory effect of STAT3 on SSBP1 transcription, and inhibited the downstream PI3K/Akt/mTOR signalling axis, ultimately activating apoptosis.

CONCLUSIONS AND IMPLICATIONS

The study delved further into elucidating the anticancer mechanism of SNG in osteosarcoma. Notably, we unravelled the previously undisclosed apoptotic potential of SSBP1 in osteosarcoma cells. This finding holds substantial promise in advancing the development of novel anticancer drugs and identification of therapeutic targets.

Sensitivity of osteosarcoma cell lines to autophagy inhibition as determined by pharmacologic and genetic manipulation

Pharmacologic inhibition of autophagy can be achieved using lysosomotropic agents such as hydroxychloroquine (HCQ) that interfere with fusion of the autophagosome to the lysosome thus preventing completion of the recycling process. The goal of the present study is to determine the sensitivity of eight canine (cOSA) and four human (hOSA) osteosarcoma tumour cell lines to antiproliferative and cytotoxic effects of lysosomal autophagy inhibitors, and to compare these results to the autophagy-dependence measured using a CRISPR/Cas9 live-cell imaging assay in OSA and other tumour cell lines. Antiproliferative and cytotoxic response to HCQ and Lys05 was determined using live cell imaging and YOYO-1 staining. CRISPR/Cas9 live cell imaging screen was done using species specific guide RNA's and transfection of reagents into cells. Response to autophagy core genes was compared to response to an essential (PCNA) and non-essential (FOXO3A) gene. cOSA and hOSA cell lines showed similar antiproliferative and cytotoxic responses to HCQ and Lys05 with median lethal dose (Dm ) values ranging from 4.6-15.8 μM and 2.1-5.1 μM for measures of anti-proliferative response, respectively. A relationship was observed between antiproliferative responses to HCQ and Lys05 and VPS34 CRISPR score with Dm values correlating with VPS34 response (r = 0.968 and 0.887) in a species independent manner. The results show that a subset of cOSA and hOSA cell lines are autophagy-dependent and sensitive to HCQ at pharmacologically-relevant exposures.

DNMT1 determines osteosarcoma cell resistance to apoptosis by associatively modulating DNA and mRNA cytosine-5 methylation

Cellular apoptosis is a central mechanism leveraged by chemotherapy to treat human cancers. 5-Methylcytosine (m5C) modifications installed on both DNA and mRNA are documented to regulate apoptosis independently. However, the interplay or crosstalk between them in cellular apoptosis has not yet been explored. Here, we reported that promoter methylation by DNMT1 coordinated with mRNA methylation by NSun2 to regulate osteosarcoma cell apoptosis. DNMT1 was induced during osteosarcoma cell apoptosis triggered by chemotherapeutic drugs, whereas NSun2 expression was suppressed. DNMT1 was found to repress NSun2 expression by methylating the NSun2 promoter. Moreover, DNMT1 and NSun2 regulate the anti-apoptotic genes AXL, NOTCH2, and YAP1 through DNA and mRNA methylation, respectively. Upon exposure to cisplatin or doxorubicin, DNMT1 elevation drastically reduced the expression of these anti-apoptotic genes via enhanced promoter methylation coupled with NSun2 ablation-mediated attenuation of mRNA methylation, thus rendering osteosarcoma cells to apoptosis. Collectively, our findings establish crosstalk of importance between DNA and RNA cytosine methylations in determining osteosarcoma resistance to apoptosis during chemotherapy, shedding new light on future treatment of osteosarcoma, and adding additional layers to the control of gene expression at different epigenetic levels.

A case of epithelioid osteoblastoma of the thoracic vertebra in a 12-year-old male: a case report and review of literature

Introduction and importance

Osteoblastoma (OB) is a rare benign bone tumor, representing less than 1% of all bone neoplasms. In contrast to the typical OB, a smaller subset known as 'epithelioid osteoblastoma (EO)' exhibits a distinctive inclination for local invasion and recurrence. This rare variant can pose diagnostic challenges, particularly due to its unclear clinical and radiological presentation.

Case presentation

This study details a clinical case of a 12-year-old boy experiencing pain from a lytic bone tumor located in the thoracic vertebrae (T3-T4), initially suggesting malignancy. Following extensive curettage, histopathological analysis confirmed the diagnosis of EO through immunohistochemical staining. Subsequent follow-up at 3 months revealed the absence of no pain or recurrence of the lesion.

Clinical discussion

Distinguishing EO from a malignant tumor requires a multidisciplinary approach, considering clinical, radiographic, and histological features that differentiate the two entities.

Conclusion

The goal of this case presentation is to increase awareness regarding this recurrent tumor variant, which poses diagnostic challenges, particularly in distinguishing it from malignant tumors, including osteosarcoma.

(E)-SIS3 suppressed osteosarcoma progression via promoting cell apoptosis, arresting cell cycle, and regulating the tumor immune microenvironment

Osteosarcoma is a prevalent malignant bone tumor with a poor prognosis. Mothers against decapentaplegic homolog 3 (Smad3) present as a therapeutic target in antitumor treatment, whereas its functions in the osteosarcoma have not been well explored. In the current study, we aimed to investigate the effects of Smad3 in the progression of osteosarcoma. The tumor immune single-cell hub 2 website was used for graph-based visualization of Smad3 status in osteosarcoma single-cell database. Western Blot was applied to detect the expression of Smad3 protein in cell lines. Colony formation and cell counting kit-8 assays were used to evaluate cell proliferation. Transwell and wound healing assays were used to detect the migration and invasion abilities of cells. Cell apoptosis rates and cell cycle changes were explored by using flow cytometry analysis. The xenograft tumor growth model was applied to explore the effect in tumor growth after Smad3 blockage in vivo. Moreover, to confirm the potential mechanism of Smad3's effects on osteosarcoma, bioinformatics analysis was performed in TARGET-Osteosarcoma and GSE19276 databases. Our study found that the Smad3 protein is overexpressed in 143B and U2OS cells, suppressing the expression of Smad3 protein in osteosarcoma cells by Smad3 target inhibitor (E)-SIS3 or lentivirus can inhibit the proliferation, migration, invasion, promote cell apoptosis, arrest cell G1 cycle in osteosarcoma cells in vitro, and suppress tumor growth in vivo. Furthermore, the bioinformatics analysis demonstrated that high expression of Smad3 is closely associated with low immune status in TARGET-Osteosarcoma and GSE19276 databases. Our study suggested that Smad3 could contribute positively to osteosarcoma progression via the regulation of tumor immune microenvironment, and Smad3 may represent as an valuable potential therapeutic target in osteosarcoma therapy.

The Combination of Methioninase and Ethionine Exploits Methionine Addiction to Selectively Eradicate Osteosarcoma Cells and Not Normal Cells and Synergistically Down-regulates the Expression of C-MYC

BACKGROUND/AIM

The fundamental and general hallmark of cancer cells, methionine addiction, termed the Hoffman effect, is due to overuse of methionine for highly-increased transmethylation reactions. In the present study, we tested if the combination efficacy of recombinant methioninase (rMETase) and a methionine analogue, ethionine, could eradicate osteosarcoma cells and down-regulate the expression of c-MYC.

MATERIALS AND METHODS

143B osteosarcoma cells and Hs27 normal human fibroblasts were tested. The efficacy of rMETase alone and ethionine, alone and in their combination, on cell viability was determined with the WST-8 assay on 143B cells and Hs27 cells. c-MYC expression was examined with western immunoblotting and compared in 143B cells treated with/without rMETase, ethionine, or the combination of both rMETase and ethionine.

RESULTS

143B cells were more sensitive to both rMETase and ethionine than Hs 27 cells, with the following IC50s: rMETase (143B: 0.22 U/ml; Hs27: 0.82 U/ml); ethionine (143B: 0.24 mg/ml; Hs27: 0.42 mg/ml). The combination of rMETase and ethionine synergistically eradicated 143B cells, lowering the IC50 for ethionine 14-fold compared to ethionine alone (p<0.001). In contrast, Hs27 fibroblasts were relatively resistant to the combination. The expression of c-MYC was significantly down-regulated only by the combination of rMETase and ethionine in 143B cells (p<0.001).

CONCLUSION

In the present study, we showed, for the first time, the synergistic combination efficacy of rMETase and ethionine on osteosarcoma cells in contrast to normal fibroblasts, which were relatively resistant. The combination of rMETase and ethionine down-regulated c-MYC expression in the cancer cells. The present results indicate the combination of rMETase and ethionine may reduce the malignancy of osteosarcoma cells and can be a potential future clinical strategy.

The knockdown of lncRNA DLGAP1-AS2 suppresses osteosarcoma progression by inhibiting aerobic glycolysis via the miR-451a/HK2 axis

Osteosarcoma (OS) is one of the most aggressive bone tumors worldwide. Emerging documents have shown that long noncoding RNAs (lncRNAs) elicit crucial regulatory functions in the process of tumorigenesis. LncRNA DLGAP1-AS2 is recognized as a regulator in several types of cancers, but its biological functions and molecular mechanisms in OS remain to be elucidated. RT-qPCR and In situ hybridization (ISH) were used to evaluate DLGAP1-AS2 expression in OS samples. Western blotting was used for the measurement of the protein levels of hexokinase 2 (HK2) and epithelial-mesenchymal transition (EMT)-related markers. The proliferation of OS cells was determined using a CCK-8 assay and EdU assay. TUNEL assay and flow cytometry were performed to assess OS cell apoptosis. Glucose metabolism in vitro assays were used. The binding relations among miR-451a, HK2, and DLGAP1-AS2 were validated by luciferase reporter assay. The cellular distribution of DLGAP1-AS2 in OS cells was determined by FISH and subcellular fractionation assays. Mouse xenograft models were established to perform the experiments in vivo. We found that DLGAP1-AS2 expression was upregulated in OS tissues and cells. Downregulation of DLGAP1-AS2 expression suppressed the malignancy of OS cells by restraining cell proliferation, the EMT process, invasiveness, migration, and aerobic glycolysis and accelerating apoptotic behaviors. Of note, silenced DLGAP1-AS2 restrained tumor growth and metastasis in vivo. However, DLGAP1-AS2 overexpression accelerated the progression of OS. We further found that DLGAP1-AS2 upregulation was induced by hypoxia and low glucose. Additionally, DLGAP1-AS2 bound to miR-451a to upregulate HK2 expression. Rescue assays revealed that the DLGAP1-AS2/miR-451a/HK2 axis contributed to OS cell malignancy by promoting aerobic glucose metabolism. Overall, these findings revealed a new regulatory pathway where DLGAP1-AS2 upregulated HK2 expression by sponging miR-451a to accelerate OS development.

Phytic acid-modified manganese dioxide nanoparticles oligomer for magnetic resonance imaging and targeting therapy of osteosarcoma

Osteosarcoma is the most common malignant tumor in the skeletal system with high mortality. Phytic acid (PA) is a natural compound extracted from plant seeds, which shows certain antitumor activity and good bone targeting ability. To develop a novel theranostics for magnetic resonance imaging (MRI) and targeting therapy of osteosarcoma, we employed PA to modify manganese dioxide nanoparticles (MnO₂@PA NPs) for osteosarcoma treatment. The MnO₂ NPs oligomer was formed by PA modification with uniformed size distribution and negative zeta potential. Fourier-transform infrared spectroscopy, X-ray diffraction, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis demonstrated that PA has been successfully modified on MnO₂ NPs, and the structure of MnO₂@PA NPs is amorphous. In vitro experiments demonstrated that MnO₂@PA NPs oligomer can be efficiently internalized by tumor cell, and the internalized NPs can react with H₂O₂ under acid microenvironment to produce Mn²⁺ and O₂. In vivo experiments demonstrated that MnO₂@PA NPs oligomer can passively accumulate in tumor tissue, and the accumulated NPs can produce Mn²⁺ and O₂ for MRI and targeting therapy of osteosarcoma. In conclusion, we prepared a novel bone-targeting nano theranostics for MRI and therapy of osteosarcoma.

Significance of the Pretreatment Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios in Predicting the Response to Neoadjuvant Chemotherapy and Survival Rates in Extremity Osteosarcoma: A Multicentre Prospective Study

OBJECTIVES

We aimed to assess the effects of pretreatment neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios on the response to neoadjuvant chemotherapy and survival rates in patients with extremity osteosarcoma.

PATIENTS AND METHODS

Patients with high-grade osteosarcoma admitted to oncologic centers affiliated with Iran University of Medical Sciences, Tehran, Iran from 2015 to 2021 were evaluated retrospectively to assess the impact of complete blood count-related parameters on the pathologic response after neoadjuvant chemotherapy. Then, patients were followed up prospectively to evaluate the survival rates. All patients received at least three cycles of cisplatin/doxorubicin regimen, preoperatively. In this study, the cut-off values for high neutrophil-to-lymphocyte and high platelet-to-lymphocyte ratio were considered 3.28 and 128, respectively.

RESULTS

One hundred eighty-six patients were enrolled. Patients with high neutrophil-to-lymphocyte ratio and high platelet-to-lymphocyte ratio had a significantly lower overall survival rates (20.7 [95% CI 18-23.5] month vs. 34.6 [95% CI 33.2-36], p = 0.003 and 21.9 [95% CI 20.2-23.6] month versus 35.3 [95% CI 33.9-36.7], p = 0.002; respectively). Moreover, disease-free survival of patients with high platelet-to-lymphocyte ratio was worse than patients with low platelet-to-lymphocyte ratio (20.4 [95% CI 18.4-22.4] month vs. 32.7 [95% CI 30.8-34.7], p = 0.02).

CONCLUSION

Our study showed that neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios at the baseline can predict the survival of patients with high-grade osteosarcoma.

Urolithin B inhibits proliferation and migration and promotes apoptosis and necrosis by inducing G2/M arrest and targeting MMP-2/-9 expression in osteosarcoma cells

Osteosarcoma (OS) is the most prevalent primary bone cancer, with a high morbidity and mortality rate. Over the past decades, therapeutic approaches have not considerably improved patients' survival rates, and further research is required to find efficient treatments for OS. Data from several studies have shown that urolithin B (UB), the intestinal metabolite of polyphenolic ellagitannins, is emerging as a new class of anticancer compounds, yet its effect on OS cancer cells remains elusive. Herein, we investigated UB's antimetastatic, antiproliferative, and apoptotic effects on the MG-63 OS cell line. Cell viability assay, annexin V/propidium iodide staining, cell cycle arrest analysis, determination of the gene expression of MMP-2, MMP-9, Bax, Bcl-2, and p53 messenger RNA (mRNA), evaluation of reactive oxygen species (ROS) generation and migration, and MMP-2 and MMP-9 protein expression assessments were performed. UB caused late apoptosis, necrosis, G2/M arrest, and ROS generation in MG-63 cells. It increased the mRNA expression of the p53 tumor suppressor and Bax proapoptotic genes. UB also inhibited the migration and metastatic behavior of MG-63 OS cells by downregulating mRNA and MMP-2 and MMP-9 protein expression. In general, although further in vivo investigations are warranted, the current results showed that UB might be utilized as a potential novel natural compound for OS therapy due to its nontoxic, antiproliferative, and antimetastatic nature.

Characterization of the gut microbiome in an osteosarcoma mouse model

Compelling evidence has mounted surrounding the relationship between the gut microbiome and many intestinal and extraintestinal cancers. Few studies exist investigating the relationship between the gut microbiome and sarcoma. We hypothesize that the presence of distant osteosarcoma induces change to the profile of flora within the mouse. Twelve mice were used for this experiment: six were sedated and received an injection of human osteosarcoma cells into the flank, while six served as controls. Baseline stool and weight were collected. Tumor size and mouse weight were recorded weekly, and stool samples were collected and stored. Fecal microbiomes of the mice were profiled by 16S rRNA gene sequencing and analyzed for alpha diversity, relative abundances of microbial taxa, and abundance of specific bacteria at different time points. Alpha diversity was increased in the osteosarcoma group compared with the control group. The family Lachnospiraceae had the second strongest negative net average change in relative abundance over time in the osteosarcoma group whereas it had a positive net average change in the control group. An increased Firmicutes/Bacteroidota (F/B) ratio was observed in the osteosarcoma group relative to the control mice. These differences suggest that there may be an interplay between the gut microbiome and osteosarcoma. Clinical significance: Due to the paucity of literature available, our work can support novel research on this relationship and the development of new, personalized treatments for osteosarcoma.

The Future of HER2-Targeted Treatment for Osteosarcoma: Lessons from the Negative Trastuzumab Deruxtecan Results

Human epidermal growth factor receptor 2 (HER2), coded by the proto-oncogene ERBB, is known to be mutated or amplified in various malignant diseases, and many HER2-targeted therapies (including monoclonal antibodies and low-molecular-weight tyrosine kinase inhibitors) have been investigated. HER2 overexpression is observed in ~30% of patients with osteosarcoma, and HER2-targeted therapy for osteosarcoma has also been investigated, along with the prognostic and/or predictive value of HER2. An effective HER2-targeted therapy for osteosarcoma has not been established, however. An antibody-drug conjugate (ADC), i.e., trastuzumab deruxtecan (T-DXd), has been approved for the treatment of HER2-positive malignant diseases such as breast cancer and gastric cancer. T-DXd showed promising efficacy in a tumor-agnostic clinical trial, but even T-DXd did not demonstrate sufficient efficacy against HER2-positive osteosarcoma. In this review, the underlying reasons/mechanisms for the failure of HER2-targeted treatments for osteosarcoma (including T-DXd) are discussed, and the potential and future direction of HER2-targeted therapy is described.

A novel ferroptosis-related microRNA signature with prognostic value in osteosarcoma

The induction of ferroptosis is suggested to be a potential therapeutic strategy for cancers. MicroRNAs (miRNAs) are reported to play an important role in cell death processes. This study aims to construct and validate a risk model based on ferroptosis-related miRNAs (FR_miRNAs) to predict prognosis and identify novel therapeutic targets for osteosarcoma. Data from the Therapeutically Applicable Research to Generate Effective Treatments database are used as the training cohort. A prognostic signature based on two FR_miRNAs (miR-635 and miR-593) is developed using univariate Cox regression, least absolute shrinkage and selection operator regression, and multivariate Cox regression analyses. The area under the curve values of the prognostic signature to predict the 1-year, 2-year, 3-year, and 5-year overall survival rates in patients with osteosarcoma are 0.782, 0.781, 0.722, and 0.777, respectively, indicating a good predictive ability. Based on the risk score, patients are divided into low-risk and high-risk groups. Patients with high-risk scores are associated with poor survival. The risk level is determined to be an independent prognostic factor. A nomogram is established for predicting prognosis. The expression levels of PRNP (miR-635-related ferroptosis-related gene (FRG); P=0.024) and HILPDA (miR-593-related FRG; P=0.025) are significantly different between the low-risk and high-risk groups. All results are validated in an external cohort (GSE39040). The results of the functional assay reveal that miR-635 mimics inhibit osteosarcoma (OS) cell proliferation and migration, whereas miR-593 overexpression exerts the opposite effect. In conclusion, miR-635 and miR-593 exert contrasting regulatory effects on OS cell proliferation and migration.

Synergistic anti-tumour activity of ginsenoside Rg3 and doxorubicin on proliferation, metastasis and angiogenesis in osteosarcoma by modulating mTOR/HIF-1α/VEGF and EMT signalling pathways

OBJECTIVES

The most common cause of osteosarcoma (OS) death is lung metastasis. Currently, doxorubicin is the primary chemotherapy drug used to treat OS, however, it is not effective in inhibiting metastasis, and it has obvious cardiotoxicity. The anticancer activity of ginsenoside Rg3 has been demonstrated in a variety of malignant tumours. The aim of this study was to determine the potential role of ginsenoside Rg3 and doxorubicin in OS and the possible mechanism.

METHODS

The potential synergistic effects of ginsenoside Rg3 and doxorubicin on human osteosarcoma cells 143B and U2OS, human umbilical vein endothelial cells, and mice receiving 143B xenografts and lung metastases were investigated.

KEY FINDINGS

Our study demonstrated that the combination of ginsenoside Rg3 and doxorubicin significantly inhibited cell proliferation, metastasis and angiogenesis in vitro. Mechanically, the anti-tumour activity of ginsenoside Rg3 and doxorubicin by modulating mTOR/HIF-1α/VEGF and EMT signalling pathways. Furthermore, ginsenoside Rg3 combined with doxorubicin inhibits tumour growth and lung metastasis in 143B-derived murine osteosarcoma models. More importantly, ginsenoside Rg3 can effectively ameliorate doxorubicin-induced weight loss and cardiotoxicity in mice.

CONCLUSIONS

Consequently, we concluded that the combination of ginsenoside Rg3 and doxorubicin displayed an evidently synergistic effect, which has the potential to be used as an effective and safe therapeutic approach for OS treatment.

A review of the development of histotripsy for extremity tumor ablation with a canine comparative oncology model to inform human treatments

Cancer is a devasting disease resulting in millions of deaths worldwide in both humans and companion animals, including dogs. Treatment of cancer is complex and challenging and therefore often multifaceted, as in the case of osteosarcoma (OS) and soft tissue sarcoma (STS). OS predominantly involves the appendicular skeleton and STS commonly develops in the extremities, resulting in treatment challenges due to the need to balance wide-margin resections to achieve local oncological control against the functional outcomes for the patient. To achieve wide tumor resection, invasive limb salvage surgery is often required, and the patient is at risk for numerous complications which can ultimately lead to impaired limb function and mobility. The advent of tumor ablation techniques offers the exciting potential of developing noninvasive or minimally invasive treatment options for extremity tumors. One promising innovative tumor ablation technique with strong potential to serve as a noninvasive limb salvage treatment for extremity tumor patients is histotripsy. Histotripsy is a novel, noninvasive, non-thermal, and non-ionizing focused ultrasound technique which uses controlled acoustic cavitation to mechanically disintegrate tissue with high precision. In this review, we present the ongoing development of histotripsy as a non-surgical alternative for extremity tumors and highlight the value of spontaneously occurring OS and STS in the pet dog as a comparative oncology research model to advance this field of histotripsy research.

High expression of integrin-binding sialoprotein (IBSP) is associated with poor prognosis of osteosarcoma

INTRODUCTION

Osteosarcoma is a malignant tumor, accounting for 20% of primary malignant bone tumors worldwide. However, the role of IBSP as a biomarker in osteosarcoma progression has not been studied yet.

METHODS

85 cases of IBSP expression and clinical characteristics were obtained from TARGET database. Through the Kaplan-Meier curve, subgroup analysis, and univariate and multivariate Cox analysis, we further assessed the independent predictive capacity of IBSP expression for overall survival (OS) and relapse-free survival (RFS).

RESULTS

The mRNA expression of IBSP was higher in osteosarcoma than normal tissue (P < 0.0001). IBSP expression grouped by vital status showed statistical differences (P = 0.042). The race (P = 0.0183), vital status (P = 0.0034), and sample type (P = 0.0020) showed significant differences. IBSP expression exhibited satisfied diagnostic ability for osteosarcoma. The univariate and multivariate analysis confirmed that IBSP expression was an independent risk factor for OS (HR = 3.425, 95% CI: 1.604-7.313, P = 0.002) and RFS (HR = 3.377, 95% CI: 1.775-6.424, P < 0.001) in osteosarcoma patients. High IBSP expression was significantly associated with poor OS and RFS (P < 0.0001). The higher IBSP expression was observed in osteosarcoma (P < 0.001), confirmed by the IHC staining. The CCK-8 and colony formation assay showed that IBSP knockdown inhibits cell proliferation while overexpression promotes cell proliferation (P < 0.05).

CONCLUSION

High expression of IBSP was associated with poor OS and RFS. IBSP could serve as a potential biomarker for osteosarcoma, which could aid in early detection and disease monitoring.

Biodistributions and Imaging of Poly(ethylene glycol)-Conjugated Silicon Quantum Dot Nanoparticles in Osteosarcoma Models via Intravenous and Intratumoral Injections

Osteosarcoma is a malignant tumor with relatively high mortality rates in children and adolescents. While nanoparticles have been widely used in assisting the diagnosis and treatment of cancers, the biodistributions of nanoparticles in osteosarcoma models have not been well studied. Herein, we synthesize biocompatible and highly photoluminescent silicon quantum dot nanoparticles (SiQDNPs) and investigate their biodistributions in osteosarcoma mouse models after intravenous and intratumoral injections by fluorescence imaging. The bovine serum albumin (BSA)-coated and poly(ethylene glycol) (PEG)-conjugated SiQDNPs, when dispersed in phosphate-buffered saline (PBS), can emit red photoluminescence with the photoluminescence quantum yield more than 30% and have very low in vitro and in vivo toxicity. The biodistributions after intravenous injections reveal that the SiQDNPs are mainly metabolized through the livers in mice, while only slight accumulation in the osteosarcoma tumor is observed. Furthermore, the PEG conjugation can effectively extend the circulation time. Finally, a mixture of SiQDNPs and indocyanine green (ICG), which complement each other in the spectral range and diffusion length, is directly injected into the tumor for imaging. After the injection, the SiQDNPs with relatively large particle sizes stay around the injection site, while the ICG molecules diffuse over a broad range, especially in the muscular tissue. By taking advantage of this property, the difference between the osteosarcoma tumor and normal muscular tissue is demonstrated.

Network pharmacology-based research on the effect of Scutellaria baicalensis on osteosarcoma and the underlying mechanism

To explore the anti-tumor effects of Scutellaria baicalensis on osteosarcoma and its mechanism. Network pharmacology and molecular docking techniques were applied to investigate the effect and mechanism of Scutellaria baicalensis on osteosarcoma (OS). We analyzed the protein-protein interaction (PPI) network for potential targets of Scutellaria baicalensis for treating osteosarcoma and identified hub targets. We used KM curves to screen for hub targets that could effectively prolong the survival time of OS patients. We systematically performed gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis of the Scutellaria baicalensis potential targets and predicted the Scutellaria baicalensis molecular mechanism and function in treating osteosarcoma. Through molecular docking, the binding process between the hub targets, which could prolong the survival time of sarcoma patients, and Scutellaria baicalensis was simulated. PPI network analysis of potential therapeutic targets discriminated 12 hub targets. The KM curves of the hub targets showed that upregulation of RXRA, RELA, ESR1, TNF, IL6, IL1B, and RB1 expression, and downregulation of MAPK1, VEGFA, MAPK14, CDK1, and PPARG expression were effective in improving the 5-year survival rate of OS patients. GO and KEGG enrichment demonstrated that Scutellaria baicalensis regulated multiple signaling pathways of OS. Molecular docking results indicated that Scutellaria baicalensis could bind freely to the above hub target, which could prolong the survival time of sarcoma patients. Scutellaria baicalensis acted on osteosarcoma by regulating a signaling network formed by hub targets connecting multiple signaling pathways. Scutellaria baicalensis appears to have the potential to serve as a therapeutic drug for osteosarcoma and to prolong the survival of OS patients.

Osteoclasts in Osteosarcoma: Mechanisms, Interactions, and Therapeutic Prospects

Osteosarcoma is an extremely malignant tumor, and its pathogenesis is complex and remains incompletely understood. Most cases of osteosarcoma are accompanied by symptoms of bone loss or result in pathological fractures due to weakened bones. Enhancing the survival rate of osteosarcoma patients has proven to be a long-standing challenge. Numerous studies mentioned in this paper, including in-vitro, in-vivo, and in-situ studies have consistently indicated a close association between the symptoms of bone loss associated with osteosarcoma and the presence of osteoclasts. As the sole cells capable of bone resorption, osteoclasts participate in a malignant cycle within the osteosarcoma microenvironment. These cells interact with osteoblasts and osteosarcoma cells, secreting various factors that further influence these cells, disrupting bone homeostasis, and shifting the balance toward bone resorption, thereby promoting the onset and progression of osteosarcoma. Moreover, the interaction between osteoclasts and various other cells types, such as tumor-associated macrophages, myeloid-derived suppressor cells, DCs cells, T cells, and tumor-associated fibroblasts in the osteosarcoma microenvironment plays a crucial role in disease progression. Consequently, understanding the role of osteoclasts in osteosarcoma has sparked significant interest. This review primarily examines the physiological characteristics and functional mechanisms of osteoclasts in osteosarcoma, and briefly discusses potential therapies targeting osteoclasts for osteosarcoma treatment. These studies provide fresh ideas and directions for future research on the treatment of osteosarcoma.

The mitochondrial energy metabolism pathway-related signature predicts prognosis and indicates immune microenvironment infiltration in osteosarcoma

BACKGROUND

Abnormalities in the mitochondrial energy metabolism pathways are closely related to the occurrence and development of many cancers. Furthermore, abnormal genes in mitochondrial energy metabolism pathways may be novel targets and biomarkers for the diagnosis and treatment of osteosarcoma. In this study, we aimed to establish a mitochondrial energy metabolism-related gene signature for osteosarcoma prognosis.

METHODS

We first obtained differentially expressed genes based on the metastatic status of 84 patients with osteosarcoma from the TARGET database. After Venn analysis of differentially expressed genes and mitochondrial energy metabolism pathway-related genes (MMRGs), 2 key genes were obtained using univariate Cox regression and least absolute shrinkage and selection operator (LASSO) regression analysis. Next, we used these 2 genes to establish a prognostic signature. Subsequent analyses elucidated the correlation between these 2 key genes with clinical features and 28 types of immune cells. Pathway changes in osteosarcoma pathogenesis under different metastatic states were clarified using gene set enrichment analysis (GSEA) of differentially expressed genes.

RESULTS

A gene signature composed of 2 key prognosis-related genes (KCNJ5 and PFKFB2) was identified. A risk score was calculated based on the gene signature, which divided osteosarcoma patients into low- or high-risk groups that showed good and poor prognosis, respectively. High expression of these 2 key genes is associated with low-risk group in patients with osteosarcoma. We constructed an accurate nomogram to help clinicians assess the survival time of patients with osteosarcoma. The results of immune cell infiltration level showed that the high-risk group had lower levels of immune cell infiltration. GSEA revealed changes in immune regulation and hypoxia stress pathways in osteosarcoma under different metastatic states.

CONCLUSION

Our study identified an excellent gene signature that could be helpful in improving the prognosis of patients with osteosarcoma.

Long non-coding RNA PRR7-AS1 promotes osteosarcoma progression via binding RNF2 to transcriptionally suppress MTUS1

Introduction

Osteosarcoma is a common bone malignant tumor in adolescents with high mortality and poor prognosis. At present, the progress of osteosarcoma and effective treatment strategies are not clear. This study provides a new potential target for the progression and treatment of osteosarcoma.

Methods

The relationship between lncRNA PRR7-AS1 and osteosarcoma was analyzed using the osteosarcoma databases and clinical sample testing. Cell function assays and tumor lung metastasis were employed to study the effects of PRR7-AS1 on tumorigenesis in vivo and in vitro. Potential downstream RNF2 of PRR7-AS1 was identified and explored using RNA pulldown and RIP. The GTRD and KnockTF database were used to predict the downstream target gene, MTUS1, and ChIP-qPCR experiments were used to verify the working mechanismy. Rescue experiments were utilized to confirm the role of MTUS1 in the pathway.

Results

Deep mining of osteosarcoma databases combined with clinical sample testing revealed a positive correlation between lncRNA PRR7-AS1 and osteosarcoma progression. Knockdown of PRR7-AS1 inhibited osteosarcoma cell proliferation and metastasis in vitro and in vivo. Mechanistically, RNA pulldown and RIP revealed that PRR7-AS1 may bind RNF2 to play a cancer-promoting role. ChIP-qPCR experiments were utilized to validate the working mechanism of the downstream target gene MTUS1. RNF2 inhibited the transcription of MTUS1 through histone H2A lysine 119 monoubiquitin. Rescue experiments confirmed MTUS1 as a downstream direct target of PRR7-AS1 and RNF2.

Discussion

We identified lncRNA PRR7-AS1 as an important oncogene in osteosarcoma progression, indicating that it may be a potential target for diagnosis and prognosis of osteosarcoma.

Identification of mitochondrial-related signature and molecular subtype for the prognosis of osteosarcoma

Mitochondria play a vital role in osteosarcoma. Therefore, the purpose of this study was to investigate the potential role of mitochondrial-related genes (MRGs) in osteosarcoma. Based on 92 differentially expressed MRGs, osteosarcoma samples were divided into two subtypes using the nonnegative matrix factorization (NMF). Ultimately, a univariate, least absolute shrinkage and selection operator (LASSO), and multivariate Cox analysis were performed to construct a prognostic risk model. The single-sample gene set enrichment analysis assessed the immune infiltration characteristics of osteosarcoma patients. Finally, we identified an osteosarcoma biomarker, malonyl-CoA decarboxylase (MLYCD), which showed downregulation. Osteosarcoma cells proliferation, migration, and invasion were effectively inhibited by the overexpression of MLYCD. Our findings will help us to further understand the molecular mechanisms of osteosarcoma and contribute to the discovery of new diagnostic biomarkers and therapeutic targets.

Single-Nuclei Multiome (ATAC + Gene Expression) Sequencing of a Primary Canine Osteosarcoma Elucidates Intra-Tumoral Heterogeneity and Characterizes the Tumor Microenvironment

Osteosarcoma (OSA) is a highly aggressive bone tumor primarily affecting pediatric or adolescent humans and large-breed dogs. Canine OSA shares striking similarities with its human counterpart, making it an invaluable translational model for uncovering the disease's complexities and developing novel therapeutic strategies. Tumor heterogeneity, a hallmark of OSA, poses significant challenges to effective treatment due to the evolution of diverse cell populations that influence tumor growth, metastasis, and resistance to therapies. In this study, we apply single-nuclei multiome sequencing, encompassing ATAC (Assay for Transposase-Accessible Chromatin) and GEX (Gene Expression, or RNA) sequencing, to a treatment-naïve primary canine osteosarcoma. This comprehensive approach reveals the complexity of the tumor microenvironment by simultaneously capturing the transcriptomic and epigenomic profiles within the same nucleus. Furthermore, these results are analyzed in conjunction with bulk RNA sequencing and differential analysis of the same tumor and patient-matched normal bone. By delving into the intricacies of OSA at this unprecedented level of detail, we aim to unravel the underlying mechanisms driving intra-tumoral heterogeneity, opening new avenues for therapeutic interventions in both human and canine patients. This study pioneers an approach that is broadly applicable, while demonstrating significant heterogeneity in the context of a single individual's tumor.

Corrigendum: miR-766-3p targeting BCL9L suppressed tumorigenesis, epithelial-mesenchymal transition, and metastasis through the β-catenin signaling pathway in osteosarcoma cells

[This corrects the article DOI: 10.3389/fcell.2020.594135.].

Oncogenic and immunological values of RBM34 in osteosarcoma and its pan-cancer analysis

RNA binding proteins (RBPs) are increasingly recognized as potential factors influencing the advancement, prognostication, and immune response in various solid tumors. Nevertheless, the comprehensive understanding of RBM34's biological mechanisms within the tumor microenvironment remains incomplete, necessitating further systematic pan-cancer investigations to ascertain its diagnostic, prognostic, and immunological significance. In this study, the TCGA, CCLE, HPA, GTEX, and TARGET databases were employed to analyze the expression abundance and subcellular localization of RBM34 in diverse tumor types. Kaplan-Meier survival analyses were used to investigate the impact of RBM34 on clinical prognosis. We implemented the TISIDB portal, CIBERSORT, and ESTIMATE algorithms to assess the correlation between RBM34 expression and immunomodulators, chemokines, and tumor-infiltrating lymphocytes (TILs) in both pan-cancer and osteosarcoma. The CGP database was applied to evaluate the half-maximal inhibitory concentrations of targeted drugs, while TMB, MSI, and MMR were utilized to predict the efficacy of tumor immunotherapy. Furthermore, an RBM34-derived prognostic index (RDPI) was constructed for osteosarcoma patients and linked to outcomes and immune status. Finally, we examined the modulation of RBM34 knockdown on osteosarcoma proliferation and migration capacity. Our results indicate that RBM34 was predominantly localized in the nucleus and differentially expressed in most human cancer types. Kaplan-Meier curve analysis and Cox regression demonstrated that RBM34 expression affected four survival metrics including overall survival (OS) in multiple tumors and was an independent prognostic factor for osteosarcoma. In immunological characterization, RBM34 expression was significantly associated with pan-cancer immunomodulator-related molecules, lymphocyte subpopulation infiltration, and biomarkers of immunotherapy response. Subsequent in vitro experiments provided additional evidence that the suppression of RBM34 impeded the migratory and invasive capabilities of osteosarcoma. Moreover, the utilization of RDPI demonstrated its reliability in prognosticating patient outcomes and estimating the individual immune landscape. Marked differences in multiple TILs (including naive B cells, CD8+ T cells, resting dendritic cells, and activated CD4+ memory T cells) and cancer-associated fibroblast proportion were observed in diverse RDPI score subgroups. Generally, RBM34 exhibited associations with clinical prognosis, immune infiltration, and immunotherapy across various cancer types, and may also serve as a viable therapeutic target for osteosarcoma.

The combination of baseline neutrophil to lymphocyte ratio and dynamic changes during treatment can better predict the survival of osteosarcoma patients

Background

Osteosarcoma is a primary malignant bone tumor with a high metastatic potential that accounts for a significant proportion of all bone tumors. The prognosis for patients with metastatic or recurrence disease remains poor. The neutrophil-to-lymphocyte ratio (NLR) has become a potential prognostic biomarker for cancer. Recent evidence suggests that the dynamic changes in neutrophil-to-lymphocyte ratio (NLR) during treatment may be more informative in predicting patient prognosis, but the value of dynamic NLR in osteosarcoma has not yet been determined.

Methods

This retrospective study retrospectively analyzed the clinical information of 251 osteosarcoma patients diagnosed and treated in West China Hospital of Sichuan University, explored the impact of baseline NLR and changes in NLR during treatment on the prognosis of osteosarcoma patients, and further combined baseline NLR with Delta NLR to build an NLR staging system.

Results

The results showed that both baseline NLR and delta NLR had some predictive ability for the prognosis of osteosarcoma patients (P = 6.90e-4, P = 0.022). Patients with high baseline NLR were more likely to have a decrease in delta NLR (P = 1.24e-10). The NLR stage had a better predictive ability than baseline NLR and delta NLR, and was an independent prognostic factor for overall survival in osteosarcoma patients HR: 2.456 (1.625-3.710) (P = 1.97e-05).

Conclusion

NLR has value in continuous monitoring, and continuous monitoring of NLR can better predict the survival of osteosarcoma patients compared to baseline NLR.

Apatinib plus chemotherapy for non-metastatic osteosarcoma: a retrospective cohort study

Background

Effective adjuvant therapy for osteosarcoma is necessary for improved outcomes. Previous studies demonstrated that apatinib plus doxorubicin-based chemotherapy may improve the efficacy of neoadjuvant therapy. This study aimed to clarify the effectiveness and safety of apatinib plus doxorubicin and cisplatin (AP) as neoadjuvant therapy for osteosarcoma.

Methods

The clinical data of osteosarcoma patients who underwent neoadjuvant therapy and surgery between August 2016 and April 2022 were retrospectively collected and analyzed. Patients were divided into two groups: the apatinib plus AP (apatinib + AP) group and the methotrexate, doxorubicin, and cisplatin (MAP) group.

Results

This study included 42 patients with nonmetastatic osteosarcoma (19 and 23 patients in the apatinib + AP and MAP groups, respectively). The 1- and 2-year disease-free survival rates in the apatinib + AP group were higher than those in the MAP group, but the difference was not significant (P=0.165 and 0.283, respectively). Some adverse events were significantly more common in the apatinib + AP group than in the MAP group, including oral mucositis (grades 3 and 4) (52.6% vs. 17.4%, respectively, P=0.023), limb edema (47.4% vs. 17.4%, respectively, P=0.049), hand-foot syndrome (31.6% vs. 0%, respectively, P=0.005), proteinuria (26.3% vs. 0%, respectively, P=0.014), hypertension (21.1% vs. 0%, respectively, P=0.035), and hypothyroidism (21.1% vs. 0%, respectively, P=0.035). No drug-related deaths occurred. There was no statistically significant difference in the incidence of postoperative complications between the groups (P>0.05).

Conclusion

The present study suggests that apatinib + AP may be a promising candidate for neoadjuvant therapy for osteosarcoma, warranting further validation in prospective randomized controlled clinical trials with long-term follow-up.

Vertebral Osteosarcoma in Two Cats-Diagnosis, Treatment, and Outcome

In this case report, we describe the diagnosis, treatment, and outcome of two feline cases of vertebral osteosarcoma. Case 1: A 6-year-old female neutered domestic longhaired cat was presented with progressive paraparesis, ataxia, and spinal hyperesthesia. MRI of the thoracolumbar spinal cord and vertebral column revealed a strongly contrast-enhancing mass lesion originating from the dorsal lamina and spinous process of T13. The lesion caused extradural compression of the spinal cord. Surgical debulking was performed, and the histopathological evaluation of surgical biopsies was consistent with vertebral osteosarcoma. The cat was paraplegic with intact nociception post-surgery. Subsequently, the cat recovered ambulation while remaining mildly ataxic and paraparetic at long-term follow-up. Post-operative chemotherapy was started with doxorubicin. CT scans at 2, 4, 9, 13, and 20 months post-surgery showed no signs of local recurrence or metastasis. Case 2: A 15.5-year-old male neutered domestic shorthaired cat was presented with progressive paraparesis, tail paresis, and spinal hyperesthesia. Radiographs and CT scan of the lumbar vertebral column showed a large mass originating from the dorsal lamina and spinous process of L6, suggestive of neoplasia, with severe compression of the spinal cord. Surgical debulking was performed, and the histopathological evaluation was consistent with vertebral osteosarcoma. Post-operative chemotherapy was started with doxorubicin. Seven months post-surgery, the patient was neurologically normal with no signs of metastatic disease. This case report highlights the possibility of good outcomes after the surgical treatment of feline vertebral osteosarcoma supplemented with post-surgical chemotherapy.

Targeting GD2-positive Refractory/Resistant Neuroblastoma and Osteosarcoma with Anti- CD3 x Anti-GD2 Bispecific Antibody Armed T cells

Background

Since treatment of neuroblastoma (NB) with anti-GD2 monoclonal antibodies provides a survival benefit in children with minimal residual disease and our preclinical study shows that anti-CD3 x anti-GD2 bispecific antibody (GD2Bi) armed T cells (GD2BATs) were highly cytotoxic to GD2+ cell lines, we conducted a phase I/II study in recurrent/refractory patients to establish safety and explore the clinical benefit of GD2BATs.

Methods

The 3+3 dose escalation study (NCT02173093) phase I involved 9 evaluable patients with NB (n=5), osteosarcoma (OST) (n=3), and desmoplastic small round cell tumors (DSRCT) (n=1) with twice weekly infusions of GD2BATs at 40, 80, or 160 x 106 GD2BATs/kg/infusion with daily interleukin 2 (300,000 IU/m2) and twice weekly granulocyte-macrophage colony stimulating factor (250 μg/m2). Phase II portion of the trial was conducted in patients with NB at the dose 3 level of 160 x 106 GD2BATs/kg/infusion but failed to enroll the planned number of patients.

Results

Nine of 12 patients in the phase I completed therapy. There were no dose limiting toxicities (DLTs). All patients developed mild and manageable cytokine release syndrome (CRS) with grade 2-3 fevers/chills, headaches, and occasional hypotension up to 72 hours after GD2BAT infusions. GD2-antibody associated pain was not significant in this study. The median OS for patients in the Phase I and limited Phase II was 18.0 and 31.2 months, respectively, whereas the combined OS was 21.1 months. There was a complete bone marrow response with overall stable disease in one of the phase I patients with NB. Ten of 12 phase II patients were evaluable for response: 1 had partial response. Three additional patients were deemed to have clinical benefit with prolonged stable disease. More than 50% of evaluable patients showed augmented immune responses to GD2+ targets after GD2BATs as measured by interferon-gamma (IFN-γ) EliSpots, Th1 cytokines, and/or chemokines.

Conclusions

Our study demonstrated safety of up to 160 x 106 cells/kg/infusion of GD2BATs. Combined with evidence for the development of post treatment endogenous immune responses, this data supports further investigation of GD2 BATs in larger Phase II clinical trials.