Primary Bone Tumor In Children Research Articles

Patterns and treatment outcomes of primary bone tumors in children treated at tertiary referral hospital, Ethiopia

BackgroundBone tumors account for approximately 6% of all cancers in children. Malignant bone tumors, commonly occurring in children and adolescents, are associated with high mortality and morbidity. The overall survival of children with primary malignant bone tumors is affected by the stage of disease, time of diagnosis, and treatment response. Despite advanced treatment modalities with chemotherapy, surgery, and radiotherapy, bone tumor is the third leading cause of death in children with malignancy. Patients with metastatic disease at diagnosis have poor outcomes compared to localized disease at presentation. The 5-year Overall Survival and event-free survival in children with primary malignant bone tumors were 85.2% and 69.2%. The study aimed to assess the clinicopathological profile and treatment outcomes of children with primary malignant bone tumors in our setup.Materials and methodsA hospital-based cross-sectional study was conducted on 95 children who met the inclusion criteria through structured questionnaire. The collected data were analyzed using a statistical package for social sciences (SPSS) version 25. P-value < 0.05 was considered to be statistically significant. Kaplan Meier survival estimate was used for overall and event-free survival analysis.ResultsA total of ninety-five patients met the study inclusion criteria and the median age at diagnosis with primary malignant bone tumors was 10 years, with an interquartile range of 8–12 years. The duration of the illness from the onset of symptoms to the oncologic treatment center ranges from three weeks to 2 years with a mean duration of five months. Swelling was the commonest presenting symptom accounting for 95.8% (n = 91). Lower extremity was the commonest primary site of involvement accounting for 55.8% (n = 53) of children with primary malignant bone tumors. Osteosarcoma was the commonest malignant bone tumor constituted 66.3% (n = 63), followed by Ewing sarcoma at 33.7% (n = 32).About 41.2% (n = 39) of children had metastatic disease at presentation and the lung was the commonest site of distant metastasis. The Kaplan Meier survival estimate analysis showed the 1-year and 5-year overall survival probabilities for all pediatric primary malignant bone tumor patients were 65% (95% CI: 0.3–0.56) and 38% (95% CI:0.19–0.47) respectively. The 1-year and 5-year event-free survival probabilities were 55% (95% CI: 0.32–0.73) and 33% (95% CI: 0.10–0.59). The stage of the disease at presentation had a significant association with the outcome (p = 0.023).ConclusionOur study showed the mean duration of the illness from the onset of symptoms to the oncologic treatment center was 5 months ranging from 3 weeks to 2 years. More than one-third of the presented with metastatic disease at presentation. The 1-year and 5-year overall survival (OS) probabilities of children with primary malignant bone tumors were low in our setup compared to other studies.

Therapeutic potential of tyrosine-protein kinase MET in osteosarcoma.

Osteosarcoma, the most prevalent primary bone tumor in children and young adults, can often be successfully treated with standard chemotherapy and surgery when diagnosed at an early stage. However, patients presenting with metastases face significant challenges in achieving a cure. Despite advancements in classical therapies over the past few decades, clinical outcomes for osteosarcoma have not substantially improved. Recently, there has been increased understanding of the biology of osteosarcoma, leading to the identification of new therapeutic targets. One such target is MET, a tyrosine kinase receptor for Hepatocyte Growth Factor (HGF) encoded by the MET gene. In vitro and in vivo studies have demonstrated that the HGF/MET pathway plays a crucial role in cancer growth, invasion, metastasis, and drug resistance across various cancers. Clinical trials targeting this pathway are already underway for lung cancer and hepatocellular carcinoma. Moreover, MET has also been implicated in promoting osteosarcoma progression. This review summarizes 3decades' worth of research on MET's involvement in osteosarcoma and further explores its potential as a therapeutic target for patients with this disease.

The significance of surveillance imaging in children with Ewing sarcoma and osteosarcoma

Primary bone tumors in children and adolescents, while rare, pose significant challenges in diagnosis and management. Children treated for Ewing sarcoma and osteosarcoma are offered a 5-year follow-up program after end of treatment, including radiological surveillance of primary location of tumor and the lungs. There is no consensus regarding how often and how the children should be followed with radiological imaging. This retrospective descriptive study of 69 patients (34 with Ewing sarcoma and 35 with osteosarcoma) investigated the consequences of abnormal findings in 1279 follow-up images. Nine relapses were detected, 4 in the Ewing group (3 local and 1 pulmonary) and 5 in the osteosarcoma group (1 local and 4 pulmonary). Of these, only two patients exhibited symptomatic relapses, with the remainder identified through imaging. The positive predictive value for relapse detection was 0.44 in the Ewing group, and 0.5 in the osteosarcoma group. In the Ewing sarcoma patient image follow-up program, the probability of anomaly detection was 12% (95% CI, 10–15). For osteosarcoma patients, the likelihood was 6% (95% CI, 4–8). Our data indicates that abnormal findings on follow-up images rarely represents relapse of tumor. As the surveillance protocol differs between the patient groups, wherein Ewing sarcoma patients primarily are monitored through MRI while osteosarcoma patients are predominantly tracked via X-rays, there is an increased occurrence of incidental findings in the first group. However, it is imperative to interpret imaging data in conjunction with clinical information, avoiding isolated reliance on imaging results when making treatment decisions.

Circular RNA IARS modulates the progression and ferroptosis of osteosarcoma via sponging miR-188-5p from RAB14.

Osteosarcoma (OS) is a common primary bone tumor in children and adolescents. Circular RNA (circRNA)-IARS acts as an oncogene in multiple human tumors. However, the circ-IARS function in OS is unclear. This research aimed to elucidate the roles and mechanisms of circ-IARS in OS. In this study, circ-IARS expressions were raised in OS tissues and cells. circ-IARS expressions were closely related to clinical stage and distant metastasis. Furthermore, overall survival rates were reduced in OS patients with high circ-IARS levels. Also, silencing circ-IARS weakened OS cell proliferation and invasion, yet enhanced cell ferroptosis. Mechanistically, circ-IARS targeted miR-188-5p to regulate RAB14 expressions in OS cells. Moreover, circ-IARS knockdown repressed OS cell proliferation, invasion, and induced ferroptosis, yet these impacts were abolished by co-transfection with anti-miR-188-5p or pcDNA-RAB14. Meanwhile, interference with circ-IARS reduced OS cell proliferation, and decreased RAB14 (a member of the RAS oncogene family), GPX4, and xCT (crucial ferroptosis regulators) expressions in vivo. In conclusion, circ-IARS facilitated OS progression via miR-188-5p/RAB14.

Primary Chest Wall Ewing Sarcoma with Indolent Behavior in an Elderly Male

Abstract Introduction/Objective Ewing sarcoma (ES) is the second most common primary malignant bone tumor, primarily affecting children and young adults within the first two decades of life. Over 80% of cases are positive for CD99 and exhibit a characteristic t(11;22) translocation resulting in an EWSR1::FLI1 fusion. Extraosseous ES is extremely rare and most reported cases occur in patients less than 50 years old. We report an unusual case of extraosseous ES arising from the chest wall in an elderly male that showed slow interval progression on imaging studies. Methods/Case Report An 83-year-old male with a past medical history of COPD and tobacco use presented to the emergency department for a mechanical ground level fall and a worsening cough over the prior week. Of note, he was found to have a 6.1 cm pleural based mass seven years prior. The patient was ultimately discharged home with recommended oncologic follow-up for this long-standing chest wall mass due to an increase in size on imaging. A PET scan showed a hypermetabolic subpleural mass in the right lower chest wall measuring 7.6 cm with invasion through the adjacent ribs and intercostal spaces into the adjacent soft tissue. A core biopsy was performed, which demonstrated a small round blue cell tumor diffusely positive for CD99 and Bcl-2, lacking significant mitotic activity and necrosis. Given the unusual clinical features, a next generation sequencing (NGS) panel for sarcoma fusions was performed and identified an EWSR1::FLI1 fusion, supporting the diagnosis of ES/primitive neuroectodermal tumor (PNET). Results (if a Case Study enter NA) NA Conclusion ES is relatively common as a primary bone tumor in children and young adults, but is rare in the chest wall and pleura and is extremely rare in the elderly. The clinical course for ES is typically aggressive. Diagnosis of ES can be challenging as CD99 positivity is nonspecific. The characteristic t(11;22) EWSR1::FLI1 fusion can be identified through FISH or NGS. At 83 years old, this is, to our knowledge, the oldest patient reported in the literature with this diagnosis. The slow interval growth of this mass over a period of seven years is also unusual. These combined clinicopathologic features are exceedingly unique and expand upon the reported spectrum and behavior of the Ewing’s family of sarcomas. The use of broad NGS panels among pathologists may result in increased identification of ES in unusual clinical settings in the future, while also providing more confident pathologic classification in challenging situations.

Rewiring innate and adaptive immunity with TLR9 agonist to treat osteosarcoma

BackgroundOsteosarcoma (OS) is the most common primary bone tumor in children and adolescent. Surgery and multidrug chemotherapy are the standard of treatment achieving 60–70% of event-free survival for localized disease at diagnosis. However, for metastatic disease, the prognosis is dismal. Exploiting immune system activation in the setting of such unfavorable mesenchymal tumors represents a new therapeutic challenge.MethodsIn immune competent OS mouse models bearing two contralateral lesions, we tested the efficacy of intralesional administration of a TLR9 agonist against the treated and not treated contralateral lesion evaluating abscopal effect. Multiparametric flow cytometry was used to evaluate changes of the tumor immune microenviroment. Experiments in immune-deficient mice allowed the investigation of the role of adaptive T cells in TLR9 agonist effects, while T cell receptor sequencing was used to assess the expansion of specific T cell clones.ResultsTLR9 agonist strongly impaired the growth of locally-treated tumors and its therapeutic effect also extended to the contralateral, untreated lesion. Multiparametric flow cytometry showed conspicuous changes in the immune landscape of the OS immune microenvironment upon TLR9 engagement, involving a reduction in M2-like macrophages, paralleled by increased infiltration of dendritic cells and activated CD8 T cells in both lesions. Remarkably, CD8 T cells were needed for the induction of the abscopal effect, whereas they were not strictly necessary for halting the growth of the treated lesion. T cell receptor (TCR) sequencing of tumor infiltrating CD8 T cells showed the expansion of specific TCR clones in the treated tumors and, remarkably, their selected representation in the contralateral untreated lesions, providing the first evidence of the rewiring of tumor-associated T cell clonal architectures.ConclusionsOverall these data indicate that the TLR9 agonist acts as an in situ anti-tumor vaccine, activating an innate immune response sufficient to suppress local tumor growth while inducing a systemic adaptive immunity with selective expansion of CD8 T cell clones, which are needed for the abscopal effect.Graphical

Epigenetic Changes Associated with Osteosarcoma: A Comprehensive Review.

Osteosarcoma is the most common malignant primary bone tumor in children and adolescents. While clinical outcomes have improved, the 5-year survival rate is only around 60% if discovered early and can require debilitating treatments, such as amputations. A better understanding of the disease could lead to better clinical outcomes for patients with osteosarcoma. One promising avenue of osteosarcoma research is in the field of epigenetics. This research investigates changes in genetic expression that occur above the genome rather than in the genetic code itself. The epigenetics of osteosarcoma is an active area of research that is still not fully understood. In a narrative review, we examine recent advances in the epigenetics of osteosarcoma by reporting biomarkers of DNA methylation, histone modifications, and non-coding RNA associated with disease progression. We also show how cancer tumor epigenetic profiles are being used to predict and improve patient outcomes. The papers in this review cover a large range of epigenetic target genes and pathways that modulate many aspects of osteosarcoma, including but not limited to metastases and chemotherapy resistance. Ultimately, this review will shed light on the recent advances in the epigenetics of osteosarcoma and illustrate the clinical benefits of this field of research.

Effect of dual properties of regorafenib in osteosarcoma on tumor progression and bone parameters in mouse preclinical models.

e23501 Background: Osteosarcoma (OS) constitutes the most frequent malignant primary bone tumor in children and young adults. Actual treatments in OS are based in a multimodal therapy that combines pre- and post-surgery polychemotherapies including cisplatin, doxorubicin, ifosfamide and/or methotrexate. Regardless the use of this polychemotherapeutic approach, the five years overall survival for patients has not improved during the last four decades and there is a clinical need to identify new active drugs in OS. An interesting strategy implies the use of compounds that showed therapeutic benefits in other solid tumors. Regorafenib, a small molecule with multi-target tyrosine kinase inhibitory activity against FGFR-1 and -2, KIT, PDGFR, RAF, RET, TIE2 and VEGFR-1, -2 and -3, showed an anti-angiogenic/oncogenic properties in various solid tumors that includes metastatic colorectal cancer, hepatocarcinoma and breast cancer. In addition, regorafenib also inhibits in vitro the proliferation of several pediatric solid tumor cell lines such as rhabdomyosarcoma, Ewing sarcoma and OS. Methods: The present work aims to decipher the in vitro and in vivo effects of regorafenib in OS preclinical models. Results: The treatment of MNNG-HOS, KHOS and 143B osteosarcoma cell lines with Regorafenib resulted in the inhibition of cell proliferation in a dose dependent manner. The gene expression profiles of MNNG-HOS and 143B cells treated or not with regorafenib and analyzed by NanoString technology revealed a specific regulation of molecular pathways by regorafenib in both cell lines. The in vivo effect of regorafenib was then analyzed in immunocompetent (mouse MOS-J cells inoculated in C57Bl/6 mice) and immunodeficient (human MNNG-HOS and 143B OS cells injected in Nude mice) murine osteosarcoma models. In all the cases, a significant reduction of primary tumor growth was observed as well as a significant decrease of lung metastases compared to untreated mice. Interestingly, the cortical and trabecular bone mineral density were significantly increased in regorafenib treated mice compared to untreated groups as demonstrated by X ray microtomodensitometry in all models. Conclusions: Our results support the use of regorafenib as an alternative treatment in metastatic OS and demonstrated for the first time the its bone protective effect.

Identifying osteosarcoma signatures in cell free DNA using 5-hydroxymethylcytosine profiling.

10022 Background: Osteosarcoma is the most common primary bone tumor in children and adolescents. Prognostic biomarkers are limited, and post-treatment surveillance relies heavily on radiologic imaging. Capture and analysis of cell-free DNA (cfDNA) from the bloodstream is an emerging technique that could be used to provide additional prognostic information and track residual disease following treatment. 5-hydroxymethylcytosine (5-hmC) is an epigenetic marker of open chromatin and active gene expression, and tumor specific patterns of global 5-hmC deposition are identifiable in several cancers and vary according to disease burden. We profiled 5-hmC using plasma-derived cfDNA from osteosarcoma patients and healthy children to assess its utility as a biomarker of disease status. Methods: cfDNA was isolated from patients diagnosed with osteosarcoma and well child controls. Nano-hmC-Seal, a technique developed to isolate 5-hmC-modified DNA fragments, was used to generate sequencing libraries of cfDNA. Genomic DNA from osteosarcoma cell lines was serially diluted with healthy donor-derived cfDNA. DESeq2 was used to identify genes with high 5-hmC deposition in osteosarcoma cell line DNA relative to serial dilutions. In patient cfDNA samples, the relative abundance of 5-hmC deposition on these osteosarcoma genes was determined using gene set variation analysis (GSVA). GSVA returns a score ranging from -1 to 1, with positive values indicating a relative abundance of 5-hmC deposition on osteosarcoma genes. Results: The cohort consisted of 33 healthy children and 17 patients with osteosarcoma including 53 serially collected samples from these patients. 139 osteosarcoma genes were identified and used for GSVA analysis. Patients with osteosarcoma had significantly higher GSVA scores than well children (0.26 vs -0.38; p &lt; 0.001). Hierarchal clustering identified two clusters of samples from children with osteosarcoma. Cluster 1 contained samples with scores correlating with osteosarcoma-derived DNA compared to Cluster 2 (0.14 vs -0.18; p &lt; 0.001). Furthermore, Cluster 1 contained 17 of 23 samples from patients with active disease on clinical imaging (sensitivity = 74%, specificity = 57%). High 5-hmC deposition on MYC was readily identified in one sample obtained at diagnosis from the only patient with a MYC amplified tumor. Additional samples from this patient during treatment showed decreasing 5-hmC deposition on MYC, consistent with a treated tumor shedding less DNA into the blood. Additionally, decreased disease burden following surgical resection was identifiable in 5-hmC profiles (presurgical GSVA score 0.22 vs postsurgical -0.08; p = 0.004). Conclusions: Osteosarcoma 5-hmC signatures can identify patients with active disease. Monitoring cfDNA in osteosarcoma using 5-hmC profiling is a promising technique that warrants further investigation with larger patient cohorts.

Overall survival comparison between pediatric and adult Ewing sarcoma of bone and adult nomogram construction: a large population-based analysis.

Ewing sarcoma (ES) is a common primary bone tumor in children. Our study aimed to compare overall survival (OS) between pediatric and adult bone ES patients, identify independent prognostic factors and develop a nomogram for predicting OS in adult patients with ES of bone. We retrospectively analyzed data for the 2004-2015 period from the Surveillance, Epidemiology, and End Results (SEER) database. To guarantee well-balanced characteristics between the comparison groups, propensity score matching (PSM) was used. Kaplan-Meier (KM) curves were used to compare OS between pediatric and adult patients with ES of bone. Univariate and multivariate Cox regression analyses were used to screen independent prognostic factors for ES of bone, and a prognostic nomogram was constructed by using the factors identified. The prediction accuracy and clinical benefit were evaluated using receiver operating characteristic (ROC) curves, areas under the curves (AUCs), calibration curves, and decision curve analysis (DCA). Our results showed that adult ES patients had lower OS than younger ES patients. Age, surgery, chemotherapy, and TNM stage were independent risk factors for bone ES in adults and were used to develop a nomogram. AUCs for 3-, 5-, and 10-year OS were 76.4 (67.5, 85.3), 77.3 (68.6, 85.9) and 76.6 (68.6, 84.5), respectively. Calibration curves and DCA results indicated excellent performance for our nomogram. We found that ES pediatric patients have better OS than adult ES patients, and we constructed a practical nomogram to predict the 3-, 5- and 10-year OS of adult patients with ES of bone based on independent prognostic factors (age, surgery, chemotherapy, T stage, N stage and M stage).

Abstract 6713: Myc-regulated miR17, 20a modulate RANK expression in osteosarcoma

Abstract Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents. Approximately 25-30% of these tumors carry amplification of chromosome 8q24, which harbors the oncogene c-Myc, and correlates with a poor prognosis in patients with OS. To understand the mechanisms that underlie the ability of Myc to alter both the tumor and its surrounding tumor immune microenvironment (TiME), we generated and molecularly characterized an osteoblast-specific Cre-Lox-Stop-Lox;(LSL)-c-MycT58A;p53f/+ knockin genetically engineered mouse model (GEMM). Phenotypically, the Myc knockin-GEMM had rapid tumor development with a high incidence of metastasis. Myc-dependent gene signature in our murine model demonstrated significant homology to the human Myc-amplified OS.Interestingly, we noticed a significant reduction in the osteoclast (OCL) cell population in the Myc knockin OS tumor compared to the p53-driven. We found the expression of RANK was significantly downregulated in the Myc knockin tumor compared to the Non-knockin p53 heterozygous tumors. The RANK/RANKL pathway is vital in OCL maturation and bone modeling/remodeling. To understand the involvement of Myc in RANK regulation, we used murine-derived OS cell lines and transiently knocked down of Myc expression using siRNA. We observed a significant upregulation in RANK expression after Myc knockdown. To decipher the molecular mechanism behind the Myc-dependent regulation of RANK expression in OS, we looked into the Myc-mediated microRNAs. Myc regulates the expression of several microRNAs, including the polycistronic miR-17-92 cluster. The expression of miR17-5p and Mir20a-5p was significantly higher in the GEMM tumor tissue samples isolated from the Myc knockin compared to the p53-driven. Further, we validated the Myc-dependent regulation of miR-17-5p/20a-5p expression using transient knockdown of Myc in mouse Myc knockin-derived cell lines. To examine the role of miR17-5p/20a-5p on the RANK regulation, we performed both gain and loss-of-function studies using microRNA-17/20a mimics and inhibitors. After the treatment with miR-17-5p/20a-5p inhibitors, the expression of RANK was significantly upregulated whereas in the case of miR17/20a mimics reversed these effects and led to a downregulation of RANK expression. We established that miR-17-5p/20a-5p is causally responsible for at least part of the mechanism by which Myc regulates the RANK expression in OS.We concluded that the Myc-regulated miR17/20a modulates the RANK expression that is involved in the OCL cell population regulation and function in the OS. Citation Format: Bikesh Kumar Nirala, Lyazat Kurenbekova, Tajhal Patel, Ryan Lane Shuck, Atreyi Dasgupta, Nino Carlo Rainusso, Jason T. Yustein. Myc-regulated miR17, 20a modulate RANK expression in osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6713.

MIR503HG Overexpression Inhibits the Malignant Behaviors of Osteosarcoma Cells by Sponging miR-103a-3p

Osteosarcoma (OS) is the most representative primary bone tumour in children and teenagers. This study explored the regulatory effects of long noncoding RNA MIR503HG (MIR503HG) on the biological functions of OS cells, and further investigated the potential mechanism of MIR503HG function exertion by analyzing the microRNA-103a-3p (miR-103a-3p) in OS cells and tissues. The expression of MIR503HG was examined using reverse transcription-quantitative PCR. OS cell proliferation was assessed by CCK-8 assay. Transwell assay was used to evaluate the migration and invasion of OS cells. The interaction between MIR503HG and miR-103a-3p was detected using the Dual-luciferase reporter assay. Forty-six paired OS tissues were collected, and the expression and correlation of MIR503HG and miR-103a-3p were evaluated. The expression of MIR503HG were significantly decreased in both OS cells and tissues. Over-expression of MIR503HG inhibited OS cell proliferation, migration and invasion. miR-103a-3p was directly targeted by MIR503HG in OS cells, and mediated the inhibitory effects of MIR503HG on OS cell malignant behaviors. miR-103a-3p expression was upregulated in OS tissues, which was negatively correlated with MIR503HG expression levels. The expression of MIR503HG was associated with OS patients' tumor size, differentiation, distant metastasis and clinical stage. Decreased MIR503HG in OS tissues and cell lines served as a tumor suppressor by inhibiting OS cell malignant behaviors through sponging miR-103a-3p. The findings of this study may provide evidence for the development of novel therapeutic targets of OS.

Second Primary Malignancies of the Bones and Joints: More Common than Expected in Osteosarcoma Patients

Osteosarcoma is the most common primary bone tumor in children, adolescents, and young adults. Second primary malignancies (SPMs) are a potential serious long-term event that can occur in osteosarcoma survivors. The National Cancer Institute's Surveillance, Epidemiology, and End Results 18 database was queried for all osteosarcoma cases from 2000 through 2015. Standardized incidence ratio (SIR) and absolute excess risk (AER) of SPM per 10,000 persons (AER) relative to representative population-level data were calculated across for various anatomic locations. In total, 3438 patients with osteosarcoma were identified. Of these patients, 79 (2.3%) developed SPMs, with an SIR of 2.84 (95% confidence interval [CI] 2.35 to 3.39, P < 0.0001) and an AER of 44.96. The most common SPMs were tumors of the bones or joints (SIR 73.07, CI, 38.90 to 124.94, P < 0.0001, AER 7.48), tumors of soft tissues including the heart (SIR 15.19, CI, 5.58 to 33.07, P < 0.0001, AER 3.27), and leukemia (SIR 22.28, CI, 15.03 to 31.80, P < 0.0001, AER 16.74). The overall incidence of SPMs in osteosarcoma survivors was significantly higher than would otherwise be expected for this population. Considering the occurrence and targeting surveillance for SPM in the osteosarcoma patient population is warranted.

Vascular Niche Facilitates Acquired Drug Resistance to c-Met Inhibitor in Originally Sensitive Osteosarcoma Cells.

Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents characterized by drug resistance and poor prognosis. As one of the key oncogenes, c-Met is recognized as a promising therapeutic target for OS. In this report, we show that c-Met inhibitor PF02341066 specifically killed OS cells with highly phosphorylated c-Met in vitro. However, the inhibitory effect of PF02341066 was abrogated in vivo due to interference from the vascular niche. OS cells adjacent to microvessels or forming vascular mimicry suppressed c-Met expression and phosphorylation. Moreover, VEGFR2 was activated in OS cells and associated with acquired drug resistance. Dual targeting of c-Met and VEGFR2 could effectively shrink the tumor size in a xenograft model. c-Met-targeted therapy combined with VEGFR2 inhibition might be beneficial to achieve an ideal therapeutic effect in OS patients. Together, our results confirm the pivotal role of tumor heterogeneity and the microenvironment in drug response and reveal the molecular mechanism underlying acquired drug resistance to c-Met-targeted therapy.

Imaging of pediatric bone tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Malignant primary bone tumors are uncommon in the pediatric population, accounting for 3%-5% of all pediatric malignancies. Osteosarcoma and Ewing sarcoma comprise 90% of malignant primary bone tumors in children and adolescents. This paper provides consensus-based recommendations for imaging in children with osteosarcoma and Ewing sarcoma at diagnosis, during therapy, and after therapy.

Novel Targeting of DNA Methyltransferase Activity Inhibits Ewing Sarcoma Cell Proliferation and Enhances Tumor Cell Sensitivity to DNA Damaging Drugs by Activating the DNA Damage Response.

DNA methylation is an important component of the epigenetic machinery that regulates the malignancy of Ewing sarcoma (EWS), the second most common primary bone tumor in children and adolescents. Coordination of DNA methylation and DNA replication is critical for maintaining epigenetic programming and the DNMT1 enzyme has been demonstrated to have an important role in both maintaining the epigenome and controlling cell cycle. Here, we showed that the novel nonnucleoside DNMT inhibitor (DNMTi) MC3343 induces a specific depletion of DNMT1 and affects EWS tumor proliferation through a mechanism that is independent on DNA methylation. Depletion of DNMT1 causes perturbation of the cell cycle, with an accumulation of cells in the G1 phase, and DNA damage, as revealed by the induction of γH2AX foci. These effects elicited activation of p53-dependent signaling and apoptosis in p53wt cells, while in p53 mutated cells, persistent micronuclei and increased DNA instability was observed. Treatment with MC3343 potentiates the efficacy of DNA damaging agents such as doxorubicin and PARP-inhibitors (PARPi). This effect correlates with increased DNA damage and synergistic tumor cytotoxicity, supporting the use of the DNMTi MC3343 as an adjuvant agent in treating EWS.

Osteosarcoma: Novel prognostic biomarkers using circulating and cell-free tumour DNA

AimOsteosarcoma (OS) is the most common primary bone tumour in children and adolescents. Circulating free (cfDNA) and circulating tumour DNA (ctDNA) are promising biomarkers for disease surveillance and prognostication in several cancer types; however, few such studies are reported for OS. The purpose of this study was to discover and validate methylation-based biomarkers to detect plasma ctDNA in patients with OS and explore their utility as prognostic markers. MethodsCandidate CpG markers were selected through analysis of methylation array data for OS, non-OS tumours and germline samples. Candidates were validated in two independent OS datasets (n = 162, n = 107) and the four top-performing markers were selected. Methylation-specific digital droplet PCR (ddPCR) assays were designed and experimentally validated in OS tumour samples (n = 20) and control plasma samples. Finally, ddPCR assays were applied to pre-operative plasma and where available post-operative plasma from 72 patients with OS, and findings correlated with outcome. ResultsCustom ddPCR assays detected ctDNA in 69% and 40% of pre-operative plasma samples (n = 72), based on thresholds of one or two positive markers respectively. ctDNA was detected in 5/17 (29%) post-operative plasma samples from patients, which in four cases were associated with or preceded disease relapse. Both pre-operative cfDNA levels and ctDNA detection independently correlated with overall survival (p = 0.0015 and p = 0.0096, respectively). ConclusionOur findings illustrate the potential of mutation-independent methylation-based ctDNA assays for OS. This study lays the foundation for multi-institutional collaborative studies to explore the utility of plasma-derived biomarkers in the management of OS.

Effect of Polymorphisms in Drug Transporters on Cisplatin Efficacy and Nephrotoxicity in Paediatric Osteosarcoma

Introduction: Osteosarcoma (OS) is the most common type of primary bone tumor in children and adolescents. Chemotherapeutic resistance to cisplatin represents such a significant barrier in the successful treatment of Osteosarcoma. The degree of nephrotoxicity and drug resistance (poor tumor necrosis) is associated with cisplatin accumulation in cells which is governed by Copper transporter protein 1 (CTR1) and Organic cation transporter 2 (OCT2). This study aims to determine the allelic frequency of CTR1 and OCT2 single nucleotide polymorphisms (SNPs) in osteosarcoma patients. In addition, detect the relation between SNPs in transporters and cisplatin efficacy or nephrotoxicity.&#x0D; Methods: A group of 120 pediatric osteosarcoma patients was recruited and genotyped for CTR1, rs7851395, and OCT2 rs316019. We detected the allelic frequency of the two gene polymorphisms. We defined good responders versus poor responders depending on tumor necrosis parameters and looked at nephrotoxicity and serum electrolytes according to CTCAEv4 using the Chi-square test (c2) and Kruskal-Wallis value, the odds ratio and confidence interval were calculated too.&#x0D; Results: We found that the C allele in (rs316019) OCT2 polymorphism was the dominant allele, and patients with (C/C genotype) were the dominant genotype (72%). and the "A" allele is the dominant allele in (rs7851395) CTR1 and patients with (A/A genotype) were (39.5%).&#x0D; Conclusion: the study had found that the "C" allele is the dominant allele in (rs316019) OCT2 and the "A" allele is the dominant allele in (rs7851395) CTR1, the study didn't find any significant relation between CTR1, OCT2 polymorphisms and cisplatin response or nephrotoxicity and farther multi center studies need to be done.

Zinc finger Asp-His-His-Cys palmitoyl -acyltransferase 19 accelerates tumor progression through wnt/β-catenin pathway and is upregulated by miR-940 in osteosarcoma

ABSTRACT Osteosarcoma (OS) is the most frequent malignant primary bone tumor in children and young adults. Zinc finger Asp-His-His-Cys palmitoyl-acyltransferase 19 (ZDHHC19) is a key enzyme in protein palmitoylation and plays crucial roles in tumor progression. However, its expression profile and biological function in OS have been unclear. In the present study, the expression level of ZDHHC19 in OS cell lines was determined by qRT-PCR and Western blot. The effect of ZDHHC19 in cell growth, invasion and migration was analyzed by CCK8, EDU, transwell, wound healing assay in vitro, and xenograft tumor model in vivo. In addition, bioinformatics analysis was used to explore the potential mechanism of ZDHHC19 in OS. Furthermore, the luciferase reporter assay was conducted to determine the direct binding between miR-940 and ZDHHC19. We discovered that ZDHHC19 was overexpressed in OS cells compared with the normal cells. The functional investigation demonstrated that ZDHHC19 silencing could inhibit proliferation, invasion and migration of OS in vitro and suppress tumorigenicity and lung metastasis in a xenograft model in vivo. Mechanistically, we identified that ZDHHC19 was a direct target of miR-940 and forced ZDHHC19 expressions partially rescue the suppression of proliferation, migration and invasion induced by miR-940. Moreover, bioinformatics analysis combined with validation experiments revealed that activating wnt/β-catenin pathway contributed to the pro-oncogenic effect induced by ZDHHC19. Furthermore, rescue experiments further verified that miR-940/ZDHHC19 axis regulated wnt/β-catenin pathway. Overall, these findings indicated that miR-940/ZDHHC19 axis played a significant role in OS progression and might be considered as a novel target for OS treatment. Abbreviations:OS, osteosarcoma; miRNAs, microRNAs; 3’-UTR, 3’- untranslated region; TARGET, Therapeutically Applicable Research To Generate Effective Treatments; qRT-PCR, quantitative real-time PCR; IHC, Immunohistochemistry; GSVA, Gene Set Variation Analysis; GSEA, Gene Set Enrichment Analysis; KEGG, Kyoto Encyclopedia of Genes and Genomes;

Recent Advances in Nanoplatforms for the Treatment of Osteosarcoma.

Osteosarcoma (OS) is the most common primary bone tumor in children and young people. Traditional surgical excision combined with chemotherapy presents many limitations, such as resistance and systemic side effects of chemotherapy drugs, postoperative recurrence, and bone defects. Given these limitations, novel therapeutic modalities for OS treatment using nanometer-sized platform-based chemotherapeutic delivery have emerged as a promising alternative therapy. This form of therapy offers multiple advantages, such as accurate delivery of the drug to the tumor site and repair of limited bone defects after tumor resection. In this review, we briefly summarize nanoplatforms, including liposomes, polymeric nanoparticles, inorganic nanoparticles, nanomicelles, dendrimers, nanocapsules, and exosomes. The essential shortcomings involved in these nanoplatforms, such as poor stability, immunogenicity, insufficient circulation, and drug leakage are also discussed, and related solutions are briefly proposed. Finally, the application prospects of nanoplatforms in the treatment of OS are discussed.