Phase-II trials in osteosarcoma recurrences: A systematic review of past experience

Development of a prognostic model for osteosarcoma based on macrophage polarization-related genes using machine learning: implications for personalized therapy

While neoadjuvant chemotherapy combined with surgical resection has improved the prognosis for patients with osteosarcoma, its impact on metastatic and recurrent cases remains limited. Immunotherapy is emerging as a promising alternative. However, the relationship between the phenotype of tumor-associated macrophages and the prognosis of osteosarcoma remains unclear. Differentially expressed gene during macrophage polarization were identified using the Monocle package. Weighted gene co-expression network analysis was conducted to select genes regulating macrophage polarization. The least absolute shrinkage and selection operator algorithm and multivariate Cox regression were used to construct long-term survival predictive strategies. Multiple machine learning algorithms identified target genes for pan-cancer analysis. Lentiviral transfection created stable strains with target gene knockdown, and CCK-8 and transwell migration assays verified the target gene's effects. Western blot and flow cytometry assessed the impact of target genes on macrophage polarization. A total of 141 genes regulating macrophage polarization were identified, from which eight genes were selected to construct prognostic models. Significant differences between high-risk and low-risk groups were observed in immune cell activation, immune-related signaling pathways, and immune function. The prognostic model and target gene were validated to provide more precise immunotherapy options for osteosarcoma and other tumors. BNIP3 knockdown decreased osteosarcoma cell proliferation and migration and promoted macrophage polarization to the M2 phenotype. The constructed prognostic model offers precise immunotherapy regimens and valuable insights into mechanisms underlying current studies. Furthermore, BNIP3 may serve as a potential immunotherapeutic target for osteosarcoma and other tumors.

From biology to personalized medicine: Recent knowledge in osteosarcoma

High-grade osteosarcoma is the most common paediatric bone cancer. More than one third of patients relapse and die of osteosarcoma using current chemotherapeutic and surgical strategies. To improve outcomes in osteosarcoma, two crucial challenges need to be tackled: 1-the identification of hard-to-treat disease, ideally from diagnosis; 2- choosing the best combined or novel therapies to eradicate tumor cells which are resistant to current therapies leading to disease dissemination and metastasize as well as their favorable microenvironment. Genetic chaos, tumor complexity and heterogeneity render this task difficult. The development of new technologies like next generation sequencing has led to an improvement in osteosarcoma oncogenesis knownledge. This review summarizes recent biological and therapeutical advances in osteosarcoma, as well as the challenges that must be overcome in order to develop personalized medicine and new therapeutic strategies and ultimately improve patient survival.

A systematic review of early phase studies for children and young people with relapsed and refractory rhabdomyosarcoma: The REFoRMS-SR project

Rhabdomyosarcoma is the commonest soft tissue sarcoma in children. Around one-third of children with rhabdomyosarcoma experience relapse or have refractory disease, which is associated with a poor prognosis. This systematic review of early phase studies in pediatric relapsed/refractory rhabdomyosarcoma was conducted to inform future research and provide accurate information to families and clinicians making difficult treatment choices. Nine databases and five trial registries were searched in June 2021. Early phase studies of interventions for disease control in patients under 18 years old with relapsed/refractory rhabdomyosarcoma were eligible. No language/geographic restrictions were applied. Studies conducted after 2000 were included. Survival outcomes, response rates, quality of life and adverse event data were extracted. Screening, data extraction and quality assessment (Downs and Black Checklist) were conducted by two researchers. Owing to heterogeneity in the included studies, narrative synthesis was conducted. Of 16,965 records screened, 129 published studies including over 1100 relapsed/refractory rhabdomyosarcoma patients were eligible. Most studies evaluated systemic therapies. Where reported, 70% of studies reported a median progression-free survival ≤6 months. Objective response rate was 21.6%. Adverse events were mostly hematological. One-hundred and seven trial registry records of 99 studies were also eligible, 63 of which report they are currently recruiting. Study quality was limited by poor and inconsistent reporting. Outcomes for children with relapsed/refractory rhabdomyosarcoma who enroll on early phase studies are poor. Improving reporting quality and consistency would facilitate the synthesis of early phase studies in relapsed/refractory rhabdomyosarcoma (PROSPERO registration: CRD42021266254).

Simvastatin/hydrogel-loaded 3D-printed titanium alloy scaffolds suppress osteosarcoma via TF/NOX2-associated ferroptosis while repairing bone defects

Postoperative anatomical reconstruction and prevention of local recurrence after tumor resection are two vital clinical challenges in osteosarcoma treatment. A three-dimensional (3D)-printed porous Ti6Al4V scaffold (3DTi) is an ideal material for reconstructing critical bone defects with numerous advantages over traditional implants, including a lower elasticity modulus, stronger bone-implant interlock, and larger drug-loading space. Simvastatin is a multitarget drug with anti-tumor and osteogenic potential; however, its efficiency is unsatisfactory when delivered systematically. Here, simvastatin was loaded into a 3DTi using a thermosensitive poly (lactic-co-glycolic) acid (PLGA)-polyethylene glycol (PEG)-PLGA hydrogel as a carrier to exert anti-osteosarcoma and osteogenic effects. Newly constructed simvastatin/hydrogel-loaded 3DTi (Sim-3DTi) was comprehensively appraised, and its newfound anti-osteosarcoma mechanism was explained. Specifically, in a bone defect model of rabbit condyles, Sim-3DTi exhibited enhanced osteogenesis, bone in-growth, and osseointegration compared with 3DTi alone, with greater bone morphogenetic protein 2 expression. In our nude mice model, simvastatin loading reduced tumor volume by 59%-77 % without organic damage, implying good anti-osteosarcoma activity and biosafety. Furthermore, Sim-3DTi induced ferroptosis by upregulating transferrin and nicotinamide adenine dinucleotide phosphate oxidase 2 levels in osteosarcoma both in vivo and in vitro. Sim-3DTi is a promising osteogenic bone substitute for osteosarcoma-related bone defects, with a ferroptosis-mediated anti-osteosarcoma effect.

A systematic review of recent phase-II trials in refractory or recurrent osteosarcoma: Can we inform future trial design?

BACKGROUND/OBJECTIVE

To analyze changes in recurrent/refractory osteosarcoma phase II trials over time to inform future trials in this population with poor prognosis.

METHODS

A systematic review of trials registered on trial registries between 01/01/2017-14/02/2022. Comparison of 98 trials identified between 2003 and 2016. Publication search/analysis for both periods, last update on 01/12/2022.

RESULTS

Between 2017 and 2022, 71 phase-II trials met our selection criteria (19 osteosarcoma-specific trials, 14 solid tumor trials with and 38 trials without an osteosarcoma-specific stratum). The trial number increased over time: 13.9 versus 7 trials/year (p = 0.06). Monotherapy remained the predominant treatment (62% vs. 62%, p = 1). Targeted therapies were increasingly evaluated (66% vs. 41%, P = 0.001). Heterogeneity persisted in the trial characteristics. The inclusion criteria were measurable disease (75%), evaluable disease (14%), and surgical remission (11%). 82% of the trials included pediatric or adolescent patients. Biomarker-driven trials accounted for 25% of the total trials. The survival endpoint use (rather than response) slightly increased (40% versus 31%), but the study H1/H0 hypotheses remained heterogeneous. Single-arm designs predominated over multiarm trials (n = 7). Available efficacy data on 1361 osteosarcoma patients in 58 trials remained disappointing, even though 21% of these trials were considered positive, predominantly those evaluating multi-targeted kinase inhibitors.

CONCLUSION

Despite observed changes in trial design and an increased number of trials investigating new therapies, high heterogeneity remained with respect to patient selection, study design, primary endpoints, and statistical hypotheses in recently registered phase II trials for osteosarcoma. Continued optimization of trial design informed by a deeper biological understanding should strengthen the development of new therapies.

Retrospective review of safety and efficacy of anlotinib in advanced osteosarcoma with metastases after failure of standard multimodal therapy

AIM

To study the safety and efficacy of anlotinib, a multitargeted tyrosine kinase inhibitor, in the treatment of advanced osteosarcoma (OSS) with metastases.

METHODS

We retrospectively studied patients with advanced OSS and metastases who received anlotinib treatment in our hospital from June 2018 to April 2020. All patients had received standard multimodal therapies, before taking anlotinib. Therapeutic doses of anlotinib were 12 mg for adults and 10 mg for children and adolescents once a day for 2 consecutive weeks, followed by a week of withdrawal. This 3-week cycle of treatment was continued until the tumor progressed rapidly or the patients failed to tolerate the side effects. Adverse drug reactions were recorded, and therapeutic efficacy was evaluated based on progression-free survival (PFS), disease control rate (DCR), overall survival (OS), and objective response rate (ORR).

RESULTS

The median PFS was 9.8 ± .9 months, and the 6- and 10-month PFS rates were 73% and 33%, respectively. The median OS was 11.4 ± .6 months. No patients achieved complete response. After 6 months of treatment, the DCR and ORR were 80% and 13%, respectively. No drug-related deaths or Grade 4 adverse events occurred in the patients. Five patients (33%) had Grade 3 adverse events. The most common drug-related adverse events were hand-food syndrome, fatigue, high blood pressure, anorexia, and pneumothorax.

CONCLUSIONS

Anlotinib had a modest therapeutic effect in patients with advanced OSS after the failure of standard treatment. The adverse events were mostly tolerable or relieved after treatment.

Longitudinal characterization of primary osteosarcoma and derived subcutaneous and orthotopic relapsed patient-derived xenograft models

Osteosarcoma is a rare bone cancer in adolescents and young adults with a dismal prognosis because of metastatic disease and chemoresistance. Despite multiple clinical trials, no improvement in outcome has occurred in decades. There is an urgent need to better understand resistant and metastatic disease and to generate in vivo models from relapsed tumors. We developed eight new patient-derived xenograft (PDX) subcutaneous and orthotopic/paratibial models derived from patients with recurrent osteosarcoma and compared the genetic and transcriptomic landscapes of the disease progression at diagnosis and relapse with the matching PDX. Whole exome sequencing showed that driver and copy-number alterations are conserved from diagnosis to relapse, with the emergence of somatic alterations of genes mostly involved in DNA repair, cell cycle checkpoints, and chromosome organization. All PDX patients conserve most of the genetic alterations identified at relapse. At the transcriptomic level, tumor cells maintain their ossification, chondrocytic, and trans-differentiation programs during progression and implantation in PDX models, as identified at the radiological and histological levels. A more complex phenotype, like the interaction with immune cells and osteoclasts or cancer testis antigen expression, seemed conserved and was hardly identifiable by histology. Despite NSG mouse immunodeficiency, four of the PDX models partially reconstructed the vascular and immune-microenvironment observed in patients, among which the macrophagic TREM2/TYROBP axis expression, recently linked to immunosuppression. Our multimodal analysis of osteosarcoma progression and PDX models is a valuable resource to understand resistance and metastatic spread mechanisms, as well as for the exploration of novel therapeutic strategies for advanced osteosarcoma.

Localized Nanoparticle-Mediated Delivery of miR-29b Normalizes the Dysregulation of Bone Homeostasis Caused by Osteosarcoma whilst Simultaneously Inhibiting Tumor Growth

Patients diagnosed with osteosarcoma undergo extensive surgical intervention and chemotherapy resulting in dismal prognosis and compromised quality of life owing to poor bone regeneration, which is further compromised with chemotherapy delivery. This study aims to investigate if localized delivery of miR-29b-which is shown to promote bone formation by inducing osteoblast differentiation and also to suppress prostate and cervical tumor growth-can suppress osteosarcoma tumors whilst simultaneously normalizing the dysregulation of bone homeostasis caused by osteosarcoma. Thus, the therapeutic potential of microRNA (miR)-29b is studied to promote bone remodeling in an orthotopic model of osteosarcoma (rather than in bone defect models using healthy mice), and in the context of chemotherapy, that is clinically relevant. A formulation of miR-29b:nanoparticles are developed that are delivered via a hyaluronic-based hydrogel to enable local and sustained release of the therapy and to study the potential of attenuating tumor growth whilst normalizing bone homeostasis. It is found that when miR-29b is delivered along with systemic chemotherapy, compared to chemotherapy alone, the therapy provided a significant decrease in tumor burden, an increase in mouse survival, and a significant decrease in osteolysis thereby normalizing the dysregulation of bone lysis activity caused by the tumor.

A novel molecular classification method for osteosarcoma based on tumor cell differentiation trajectories

Subclassification of tumors based on molecular features may facilitate therapeutic choice and increase the response rate of cancer patients. However, the highly complex cell origin involved in osteosarcoma (OS) limits the utility of traditional bulk RNA sequencing for OS subclassification. Single-cell RNA sequencing (scRNA-seq) holds great promise for identifying cell heterogeneity. However, this technique has rarely been used in the study of tumor subclassification. By analyzing scRNA-seq data for six conventional OS and nine cancellous bone (CB) samples, we identified 29 clusters in OS and CB samples and discovered three differentiation trajectories from the cancer stem cell (CSC)-like subset, which allowed us to classify OS samples into three groups. The classification model was further examined using the TARGET dataset. Each subgroup of OS had different prognoses and possible drug sensitivities, and OS cells in the three differentiation branches showed distinct interactions with other clusters in the OS microenvironment. In addition, we verified the classification model through IHC staining in 138 OS samples, revealing a worse prognosis for Group B patients. Furthermore, we describe the novel transcriptional program of CSCs and highlight the activation of EZH2 in CSCs of OS. These findings provide a novel subclassification method based on scRNA-seq and shed new light on the molecular features of CSCs in OS and may serve as valuable references for precision treatment for and therapeutic development in OS.

Paediatric Strategy Forum for medicinal product development of multi-targeted kinase inhibitors in bone sarcomas: ACCELERATE in collaboration with the European Medicines Agency with participation of the Food and Drug Administration

The eighth Paediatric Strategy Forum focused on multi-targeted kinase inhibitors (mTKIs) in osteosarcoma and Ewing sarcoma. The development of curative, innovative products in these tumours is a high priority and addresses unmet needs in children, adolescents and adults. Despite clinical and investigational use of mTKIs, efficacy in patients with bone tumours has not been definitively demonstrated. Randomised studies, currently being planned or in progress, in front-line and relapse settings will inform the further development of this class of product. It is crucial that these are rapidly initiated to generate robust data to support international collaborative efforts. The experience to date has generally indicated that the safety profile of mTKIs as monotherapy, and in combination with chemotherapy or other targeted therapy, is consistent with that of adults and that toxicity is manageable. Increasing understanding of relevant predictive biomarkers and tumour biology is absolutely critical to further develop this class of products. Biospecimen samples for correlative studies and biomarker development should be shared, and a joint academic-industry consortium created. This would result in an integrated collection of serial tumour tissues and a systematic retrospective and prospective analyses of these samples to ensure robust assessment of biologic effect of mTKIs. To support access for children to benefit from these novel therapies, clinical trials should be designed with sufficient scientific rationale to support regulatory and payer requirements. To achieve this, early dialogue between academia, industry, regulators, and patient advocates is essential. Evaluating feasibility of combination strategies and then undertaking a randomised trial in the same protocol accelerates drug development. Where possible, clinical trials and development should include children, adolescents, and adults less than 40 years. To respond to emerging science, in approximately 12 months, a multi-stakeholder group will meet and review available data to determine future directions and priorities.

NIR Responsive Injectable Nanocomposite Thermogel System Against Osteosarcoma Recurrence

Compared to traditional postoperative radiation and chemotherapy, immune checkpoint blockade (ICB) therapy demonstrates superiority by provoking own immune system to cure cancer completely even for some terminally ill patients. However, systemic administration of ICB is liable to cause severe immunity inflammation or immune storm. Here we propose an injectable, near infrared (NIR) responsive, multifunctional nanocomposite thermogel as a local ICB delivery system for cancer postsurgical therapy. By copolymerization of thermosensitive and zwitterionic monomer, the injectable thermogel with adjustable sol-gel transition temperature is obtained. Afterwards, combined with functional mesoporous nanoparticles, the platform could absorb NIR light and transfer it into heat. The generated heat will promote retro Diels-Alder reaction to degrade coating layer on nanoparticle, achieving NIR controlled ICB release. Furthermore, the local ICB delivery system is applied on an osteosarcoma postsurgical recurrence model and results indicate the platform with favorable biocompatibility could avoid early leakage of cargos and greatly increase drug content at tumor site. Besides, long-term controlled ICB release of the system effectively improve the amount of active T cells, resulting in excellent anti-tumor recurrence effect. Overall, this work suggests the local injectable nanocomposite thermogel is expected to be a promising tool for cancer postoperative therapy. This article is protected by copyright. All rights reserved.

Recent and Ongoing Research into Metastatic Osteosarcoma Treatments

The survival rate for metastatic osteosarcoma has not improved for several decades, since the introduction and refinement of chemotherapy as a treatment in addition to surgery. Over two thirds of metastatic osteosarcoma patients, many of whom are children or adolescents, fail to exhibit durable responses and succumb to their disease. Concerted efforts have been made to increase survival rates through identification of candidate therapies via animal studies and early phase trials of novel treatments, but unfortunately, this work has produced negligible improvements to the survival rate for metastatic osteosarcoma patients. This review summarizes data from clinical trials of metastatic osteosarcoma therapies as well as pre-clinical studies that report efficacy of novel drugs against metastatic osteosarcoma in vivo. Considerations regarding the design of animal studies and clinical trials to improve survival outcomes for metastatic osteosarcoma patients are also discussed.

Challenges of Systemic Therapy Investigations for Bone Sarcomas

Bone sarcoma is a rare component of malignant solid tumors that accounts for only ~0.2% of malignancies. Bone sarcomas present various histological types, and genomic mutations differ markedly by the histological types. Although there are vast mutations in various bone sarcomas, most of them are non-actionable, and even potential targetable mutations that are actionable targets in other malignancies have not shown the appropriate responses in clinical trials for bone sarcomas. Investigations of new systemic therapy, including molecular targeted therapies for bone sarcomas, have thus not progressed like those for other solid tumors. Another problem is that high rates of pediatric/adolescent and young adult patients have bone sarcomas such as osteosarcoma, and patient recruitment for clinical trials (especially randomized trials) is challenging. For pediatric patients, evaluations of tolerability and appropriate dose modifications of new drugs are needed, as their findings could provide the threshold for investigating new drugs for bone sarcomas. To solve these problems, improvements in registry systems, real world data, and pediatric extrapolation have been attempted. We review the issues regarding targeted drug investigations for bone sarcomas, focusing on the current clinical evidence and efforts to resolve these issues.

Current Insights into the Management of Late Chemotherapy Toxicities in Pediatric Osteosarcoma Patients

With ever increasing long-term, disease free survival rates, long-term toxicities of otherwise successful therapy have gained increasing importance. They can be grouped into potentially life-threatening, especially secondary malignancies and anthracycline cardiomyopathies, potentially disabling, particularly severe hearing loss and renal insufficiency, other, and rare events. Pathophysiology, frequency, and medical treatment approaches are discussed. Finally, fertility issues and quality of life issues are discussed, together with an outlook into the future. The challenge to cure as many patients as possible from osteosarcoma while enabling a life free of late effects will remain.

Phase I/II study of single-agent lenvatinib in children and adolescents with refractory or relapsed solid malignancies and young adults with osteosarcoma (ITCC-050)☆

Background

We report results from the phase I dose-finding and phase II expansion part of a multicenter, open-label study of single-agent lenvatinib in pediatric and young adult patients with relapsed/refractory solid tumors, including osteosarcoma and radioiodine-refractory differentiated thyroid cancer (RR-DTC) (NCT02432274).

Patients and methods

The primary endpoint of phase I was to determine the recommended phase II dose (RP2D) of lenvatinib in children with relapsed/refractory solid malignant tumors. Phase II primary endpoints were progression-free survival rate at 4 months (PFS-4) for patients with relapsed/refractory osteosarcoma; and objective response rate/best overall response for patients with RR-DTC at the RP2D.

Results

In phase I, 23 patients (median age, 12 years) were enrolled. With lenvatinib 14 mg/m², three dose-limiting toxicities (hypertension, n = 2; increased alanine aminotransferase, n = 1) were reported, establishing 14 mg/m² as the RP2D. In phase II, 31 patients with osteosarcoma (median age, 15 years) and 1 patient with RR-DTC (age 17 years) were enrolled. For the osteosarcoma cohort, PFS-4 (binomial estimate) was 29.0% [95% confidence interval (CI) 14.2% to 48.0%; full analysis set: n = 31], PFS-4 by Kaplan–Meier estimate was 37.8% (95% CI 20.0% to 55.4%; full analysis set) and median PFS was 3.0 months (95% CI 1.8-5.4 months). The objective response rate was 6.7% (95% CI 0.8% to 22.1%). The patient with RR-DTC had a best overall response of partial response. Some 60.8% of patients in phase I and 22.6% of patients in phase II (with osteosarcoma) had treatment-related treatment-emergent adverse events of grade ≥3.

Conclusions

The lenvatinib RP2D was 14 mg/m². Single-agent lenvatinib showed activity in osteosarcoma; however, the null hypothesis could not be rejected. The safety profile was consistent with previous tyrosine kinase inhibitor studies. Lenvatinib is currently being investigated in osteosarcoma in combination with chemotherapy as part of a randomized, controlled trial (NCT04154189), in pediatric solid tumors in combination with everolimus (NCT03245151), and as a single agent in a basket study with enrollment ongoing (NCT04447755).

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The recommended phase II dose of lenvatinib in children with relapsed/refractory solid malignant tumors is 14 mg/m².

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This dose is equivalent to the recommended dose of 24 mg/day for single-agent lenvatinib in adults with DTC.

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Single-agent lenvatinib showed activity of interest in children and young adults with osteosarcoma.

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Based on this initial report, lenvatinib is currently being investigated in combination with chemotherapy in osteosarcoma.

Anticancer effects of melatonin via regulating lncRNA JPX-Wnt/β-catenin signalling pathway in human osteosarcoma cells

Osteosarcoma (OS) is a type of malignant primary bone cancer, which is highly aggressive and occurs more commonly in children and adolescents. Thus, novel potential drugs and therapeutic methods are urgently needed. In the present study, we aimed to elucidate the effects and mechanism of melatonin on OS cells to provide a potential treatment strategy for OS. The cell survival rate, cell viability, proliferation, migration, invasion and metastasis were examined by trypan blue assay, MTT, colony formation, wound healing, transwell invasion and attachment/detachment assay, respectively. The expression of relevant lncRNAs in OS cells was determined by real-time qPCR analysis. The functional roles of lncRNA JPX in OS cells were further examined by gain and loss of function assays. The protein expression was measured by western blot assay. Melatonin inhibited the cell viability, proliferation, migration, invasion and metastasis of OS cells (Saos-2, MG63 and U2OS) in a dose-dependent manner. Melatonin treatment significantly downregulated the expression of lncRNA JPX in Saos-2, MG63 and U2OS cells. Overexpression of lncRNA JPX into OS cell lines elevated the cell viability and proliferation, which was accompanied by the increased metastasis. We also found that melatonin inhibited the OS progression by suppressing the expression of lncRNA JPX via regulating the Wnt/β-catenin pathway. Our results suggested that melatonin inhibited the biological functions of OS cells by repressing the expression of lncRNA JPX through regulating the Wnt/β-catenin signalling pathway, which indicated that melatonin might be applied as a potentially useful and effective natural agent in the treatment of OS.

lncRNA HCG11 suppresses human osteosarcoma growth through upregulating p27 Kip1

Osteosarcoma (OS) is a common malignant bone cancer threatening children and young adults. Emerging evidence indicates that long non-coding RNAs (lncRNAs) play crucial roles in the progression of OS. Herein, we want to clarify the roles of lncRNA human leukocyte antigen complex group 11 (HCG11) in OS. Our data revealed that HCG11 expression is decreased in OS, which is a result of transcriptional repression of YY1. Low HCG11 level is closely associated with larger tumor size and shorter overall survival of OS patients. HCG11 negatively regulates cell proliferation, cell cycle, DNA replication in vitro and tumor growth in vivo. HCG11 can raise p27 Kip1 expression via binding to miR-942-5p and IGF2BP2, and p27 Kip1 acts as a key effector for HCG11 exerting biological functions. In conclusion, HCG11 is downregulated in OS, and restrains OS growth both in vitro and in vivo by raising p27 Kip1 expression via binding to miR-942-5p and IGF2BP2.

Dihydromyricetin suppresses cell metastasis in human osteosarcoma through SP-1- and NF-κB-modulated urokinase plasminogen activator inhibition

BACKGROUND

Metastasis caused a decline in the 5-years survival rate of osteosarcoma. Therefore, developing new targeted therapeutics for osteosarcoma treatment is imperative. Dihydromyricetin (DHM) has several physiological functions: it counteracts inflammation, oxidation, and antitumor properties. However, the effects of DHM on osteosarcoma and its underlying mechanisms are still not well understood.

PURPOSE

In this study, we investigated the antimetastatic properties of DHM in human osteosarcoma U-2 OS and HOS cells.

METHODS

The effects of DHM (0, 25, 50, 75, and 100 μM) on cell viability, migration, and invasion were examined. Western blotting, RT-PCR, and quantitative real-time PCR (QPCR) were determined urokinase plasminogen activator (uPA) expression. The expression of transcriptional factor SP-1 and NF-κB was determined by using immunofluorescence assay, chromatin immunoprecipitation assay, and site-directed mutagenesis luciferase reporter.

RESULTS

We observed that DHM suppresses cell migration and invasion in osteosarcoma cell lines. In addition, DHM inhibits metastasis by downregulating urokinase plasminogen activator (uPA) expression. Moreover, real-time polymerase chain reaction and promoter activity assays revealed that DHM decreased uPA expression at transcription levels. Furthermore, the inhibition of uPA expression was associated with the suppression of SP-1 and NF-κB, which bind to the uPA promoter. Regardless of blocking or inducing the extracellular signal-regulated kinase (ERK) pathway, we verified that the DHM-related suppression of uPA and cell metastasis occurred through the p-ERK pathway.

CONCLUSION

We are the first study to propose that DHM suppresses osteosarcoma metastasis through the ERK pathway and through the suppression of SP-1 and NF-κB to inhibit downstream uPA expression. DHM is a potential therapeutic agent for antimetastatic therapy against osteosarcoma.

Lenvatinib with etoposide plus ifosfamide in patients with refractory or relapsed osteosarcoma (ITCC-050): a multicentre, open-label, multicohort, phase 1/2 study

BACKGROUND

Tyrosine kinase inhibitors have shown activity in osteosarcoma and might enhance the efficacy of chemotherapy. We aimed to determine the recommended phase 2 dose and antitumour activity of lenvatinib with etoposide plus ifosfamide in patients with refractory or relapsed osteosarcoma.

METHODS

This multicentre, open-label, multicohort, phase 1/2 trial was done at 17 hospitals in six countries. Eligible patients were aged 2-25 years, had relapsed or refractory osteosarcoma, measurable or evaluable disease per Response Evaluation Criteria in Solid Tumors version 1.1, Lansky play-performance score or Karnofsky performance score of 50% or higher, up to one previous VEGF or VEGF receptor-targeted therapy, and a life expectancy of at least 3 months. This study includes a combination dose-finding phase 1 part (cohort 3A) and a phase 2 combination expansion in patients with osteosarcoma (cohort 3B). Lenvatinib was administered orally at a starting dose of 11 mg/m² per day, capped at 24 mg per day, and etoposide (100 mg/m² per day) plus ifosfamide (3000 mg/m² per day) were administered intravenously on days 1-3 of each 21-day cycle for a maximum of five cycles. Lenvatinib monotherapy continued after these five cycles until disease progression, toxic effects, or patient choice to discontinue. The phase 1 primary endpoint was to determine the recommended phase 2 dose by evaluating dose-limiting toxicity and the phase 2 primary endpoint was progression-free survival at 4 months. Progression-free survival was measured in the full analysis set, which included all patients enrolled for efficacy outcomes; safety was assessed in all patients who received any study drug. This study is registered with ClinicalTrials.gov, NCT02432274.

FINDINGS

30 patients were screened for enrolment into cohort 3A between May 9, 2016, and June 3, 2019, and 22 patients for enrolment into cohort 3B between Sept 13, 2018, and July 18, 2019. Eight patients from cohort 3A and two from cohort 3B were ineligible for enrolment in the study. In phase 1, dose-limiting toxicities were observed in three patients (one in the lenvatinib 11 mg/m² combination group and two in the 14 mg/m² combination group) and the recommended phase 2 dose was determined as lenvatinib 14 mg/m² per day (with daily dose cap of 24 mg) and etoposide 100 mg/m² per day plus ifosfamide 3000 mg/m² per day administered intravenously on days 1-3 of each 21-day cycle for a maximum of five cycles. 35 patients from phase 1 (cohort 3A; n=15) and phase 2 (cohort 3B; n=20) were treated at the recommended phase 2 dose and their results were pooled. Progression-free survival at 4 months was 51% (95% CI 34-69) in 18 of 35 patients per the binomial estimate. The most common grade 3-4 treatment-emergent adverse events were neutropenia (27 [77%] of 35), thrombocytopenia (25 [71%]), anaemia (19 [54%]), and decreased white blood cell count (19 [54%]). 26 [74%] of 35 patients had serious treatment-emergent adverse events and no treatment-related deaths occurred.

INTERPRETATION

Lenvatinib with etoposide plus ifosfamide shows promising antitumour activity with no new safety signals in patients with refractory and relapsed osteosarcoma. These findings warrant further investigation in an ongoing randomised phase 2 study (NCT04154189).

FUNDING

Eisai and Merck Sharp & Dohme.

Bone sarcoma: success through interdisciplinary collaboration

PURPOSE

Osteosarcoma and Ewing sarcoma are the most frequent malignant bone tumours of childhood and adolescence. This review summarizes the oncologist's view of these diseases and their treatment.

METHODS

A non-systematic literature review was performed, the personal impressions and experience of the authors is described.

RESULTS

Local therapy and chemotherapy, each on their own, will not cure patients with malignant bone sarcomas. Together, they present a highly efficacious combination. While the most effective drugs were defined decades ago, progress since then has been limited. It is hoped that substances shown to be active in relapsed disease will be forwarded into even more efficacious frontline treatments. Good palliative therapy is necessary when cure is no longer an option.

CONCLUSION

Close interdisciplinary collaboration is the key to successful treatment of bone sarcomas in paediatric patients.

OLIE, ITCC-082: a Phase II trial of lenvatinib plus ifosfamide and etoposide in relapsed/refractory osteosarcoma

While survival rates for patients with relapsed/refractory osteosarcoma are low, kinase inhibitors have shown efficacy in its treatment. The multikinase inhibitor lenvatinib, plus ifosfamide and etoposide, showed antitumor activity in a Phase II study in patients with relapsed/refractory osteosarcoma. This Phase II randomized controlled trial (OLIE) will assess whether the combination of lenvatinib + ifosfamide + etoposide is superior to ifosfamide + etoposide alone in children, adolescents and young adults with relapsed/refractory osteosarcoma. The primary end point is progression-free survival; secondary and exploratory end points include, but are not limited to, overall survival, objective response rate, safety and tolerability, pharmacokinetic characterization of lenvatinib in the combination treatment, quality of life and quantification of baseline unresectable lesions that are converted to resectable.

Systematic Review of Recurrent Osteosarcoma Systemic Therapy

Osteosarcoma is the most frequent primary bone cancer, mainly affecting those of young ages. Although surgery combined with cytotoxic chemotherapy has significantly increased the chances of cure, recurrent and refractory disease still impose a tough therapeutic challenge. We performed a systematic literature review of the available clinical evidence, regarding treatment of recurrent and/or refractory osteosarcoma over the last two decades. Among the 72 eligible studies, there were 56 prospective clinical trials, primarily multicentric, single arm, phase I or II and non-randomized. Evaluated treatment strategies included cytotoxic chemotherapy, tyrosine kinase and mTOR inhibitors and other targeted agents, as well as immunotherapy and combinatorial approaches. Unfortunately, most treatments have failed to induce objective responses, albeit some of them may sustain disease control. No driver mutations have been recognized, to serve as effective treatment targets, and predictive biomarkers of potential treatment effectiveness are lacking. Hopefully, ongoing and future clinical and preclinical research will unlock the underlying biologic mechanisms of recurrent and refractory osteosarcoma, expanding the therapeutic choices available to pre-treated osteosarcoma patients.

Successive Osteosarcoma Relapses after the First Line O2006/Sarcome-09 Trial: What Can We Learn for Further Phase-II Trials?

Simple Summary

Osteosarcoma is the most common primary malignant bone tumour in adolescents and young adults. The survival of osteosarcoma patients has not improved for four decades. The purpose was to describe first and subsequent relapses in patients from the OS2006/Sarcome-09 trial, to help future trial design. Among the 434 patients with a confirmed osteosarcoma who achieved CR1 during first line treatment, 157 patients experienced at least one relapse. The 3-year progression-free and overall survival rates were 21% and 37%, respectively. Only a quarter of the patients were included in clinical trials at first recurrence. We want to promote randomised phase-II trials in osteosarcoma relapses, with broad inclusion criteria at study entry in terms of age and disease status, and PFS as primary endpoint. Surgery/local treatment of all residual lesions should be allowed when feasible. Single-arm trial design could be used for subsequent relapses.

Abstract

The purpose was to describe first and subsequent relapses in patients from the OS2006/Sarcome-09 trial, to help future trial design. We prospectively collected and analysed relapse data of all French patients included in the OS2006/Sarcome-09 trial, who had achieved a first complete remission. 157 patients experienced a first relapse. The median interval from diagnosis to relapse was 1.7 year (range 0.5–7.6). The first relapse was metastatic in 83% of patients, and disease was not measurable according to RECIST 1.1 criteria in 23%. Treatment consisted in systemic therapy (74%) and surgical resection (68%). A quarter of the patients were accrued in a phase-II clinical trial. A second complete remission was obtained for 79 patients. Most of them had undergone surgery (76/79). The 3-year progression-free and overall survival rates were 21% and 37%, respectively. In patients who achieved CR2, the 3y-PFS and OS rates were 39% and 62% respectively. Individual correlation between subsequent PFS durations was poor. For osteosarcoma relapses, we recommend randomised phase-II trials, open to patients from all age categories (children, adolescents, adults), not limited to patients with measurable disease (but stratified according to disease status), with PFS as primary endpoint, response rate and surgical CR as secondary endpoints.

Design strategies and evolving role of biomaterial assisted treatment of osteosarcoma

Osteosarcoma is the most commonly diagnosed form of bone cancer. It is characterized by a high risk of developing lung metastasis as the disease progresses. Standard treatment includes combination of surgical intervention, chemotherapy and radiotherapy. However, the non-specificity of potent chemotherapeutic agents often leads to major side effects. In this review, we discuss the role of various classes of biomaterials, including both organic as well as inorganic in realizing the local and systemic delivery of therapeutic agents like drugs, radioisotopes and even gene silencing agents to treat osteosarcoma. Biomaterial assisted unconventional therapies such as targeted therapy, nanotherapy, magnetic hyperthermia, gene therapy, photothermal and photodynamic therapies are also being explored. A wide variety of biomaterials including lipids, carbon-based materials, polymers, silica, bioactive glass, hydroxyapatite and metals are designed as delivery systems with the desired loading efficiency, release profile, and on-demand delivery. Among others, liposomal carriers have attracted a great deal of attention due to their capability to encapsulate both hydrophobic and hydrophilic drugs. Polymeric systems have high drug loading efficiency and stability and can even be tailored to achieve desired size and physiochemical properties. Carbon-based systems can also be seen as an upcoming class of therapeutics with great potential in treating different types of cancer. Inorganic materials like silica nanoparticles have high drug payload owing to their mesoporous structure. On the other hand, ceramic materials like bioactive glass and hydroxyapatite not only act as excellent delivery vectors but also participate in osteo-regeneration activity. These multifunctional biomaterials are also being investigated for their theranostic abilities to monitor cancer ablation. This review systematically discusses the vast landscape of biomaterials along with their challenges and respective opportunities for osteosarcoma therapy.

Survival Analysis of 3 Different Age Groups and Prognostic Factors among 402 Patients with Skeletal High-Grade Osteosarcoma. Real World Data from a Single Tertiary Sarcoma Center

Age is a known prognostic factor for many sarcoma subtypes, however in the literature there are limited data on the different risk profiles of different age groups for osteosarcoma survival. This study aims to provide an overview of survival in patients with high-grade osteosarcoma in different age groups and prognostic variables for survival and local control among the entire cohort. In this single center retrospective cohort study, 402 patients with skeletal high-grade osteosarcoma were diagnosed and treated with curative intent between 1978 and 2017 at the Leiden University Medical Center (LUMC). Prognostic factors for survival were analyzed using a Cox proportional hazard model. In this study poor overall survival (OS) and event-free survival (EFS) were associated with increasing age. Age groups, tumor size, poor histopathological response, distant metastasis (DM) at presentation and local recurrence (LR) were important independent prognostic factors influencing OS and EFS. Differences in outcome among different age groups can be partially explained by patient and treatment characteristics.

Management of sarcomas in children, adolescents and adults: Interactions in two different age groups under the umbrellas of GSF-GETO and SFCE, with the support of the NETSARC+ network

Sarcomas are a rare heterogeneous group of malignant neoplasms that can arise in almost any anatomic site and any age. Close collaboration among adult and pediatric cancer specialists in the management of these tumors is of foremost importance. In this review, we present the current multidisciplinary organization in care of patients with sarcoma in France and we review the main advances made in the last decades in systemic and radiotherapy treatment in the main sarcoma types diagnosed in children, adolescents and young adults (AYA), thanks to the international collaboration.

A Multi-Objective Approach for Anti-Osteosarcoma Cancer Agents Discovery through Drug Repurposing

Osteosarcoma is the most common type of primary malignant bone tumor. Although nowadays 5-year survival rates can reach up to 60–70%, acute complications and late effects of osteosarcoma therapy are two of the limiting factors in treatments. We developed a multi-objective algorithm for the repurposing of new anti-osteosarcoma drugs, based on the modeling of molecules with described activity for HOS, MG63, SAOS2, and U2OS cell lines in the ChEMBL database. Several predictive models were obtained for each cell line and those with accuracy greater than 0.8 were integrated into a desirability function for the final multi-objective model. An exhaustive exploration of model combinations was carried out to obtain the best multi-objective model in virtual screening. For the top 1% of the screened list, the final model showed a BEDROC = 0.562, EF = 27.6, and AUC = 0.653. The repositioning was performed on 2218 molecules described in DrugBank. Within the top-ranked drugs, we found: temsirolimus, paclitaxel, sirolimus, everolimus, and cabazitaxel, which are antineoplastic drugs described in clinical trials for cancer in general. Interestingly, we found several broad-spectrum antibiotics and antiretroviral agents. This powerful model predicts several drugs that should be studied in depth to find new chemotherapy regimens and to propose new strategies for osteosarcoma treatment.

Delivery of MutT homolog 1 inhibitor by functionalized graphene oxide nanoparticles for enhanced chemo-photodynamic therapy triggers cell death in osteosarcoma

Photodynamic therapy (PDT) generates highly toxic reactive oxygen species (ROS) during noninvasive cancer treatment. MutT homolog 1 (MTH1) protein is a DNA oxidative damage repair protease and suppressing its function may provide a strategy to enhance PDT efficacy by improving cellular sensitivity to ROS. A nanoparticle, composed of functional graphene oxide (GO) conjugated with polyethylene glycol (PEG), folic acid (FA) and photosensitizer indocyanine green (ICG), was constructed to deliver MTH1 inhibitor (TH287) and doxorubicin. The effects of this nanoparticle on biological properties and cell death of osteosarcoma cells were investigated. We further examined the endoplasmic reticulum (ER) stress and apoptosis in osteosarcoma. A xenograft tumor model was used to validate the results in vivo. This drug-carrying PEG-GO-FA/ICG nanoparticle showed combined chemo-photodynamic therapy (Chemo-PDT) to inhibit the proliferation and migration of osteosarcoma cells. Enhanced Chemo-PDT promoted both apoptosis and autophagy by suppressing the MTH1 protein and promoting the accumulation of ROS. In this study, autophagy served as a rescue pathway against cell death, and suppressing autophagy enhanced the anti-cancer effects of Chemo-PDT. However, Chemo-PDT induced apoptosis was related to the occurrence of ER stress. ROS might contribute to ER stress and further induce apoptosis via the JNK/p53/p21 pathway. These findings provide a mechanistic understanding of nanoparticle-induced cell death in osteosarcoma. The combination of Chemo-PDT with other therapies is promising as a new strategy to treat osteosarcoma. STATEMENT OF SIGNIFICANCE: Administration of chemotherapeutic drugs by traditional methods still has many problems. We designed a functionalized graphene oxide drug delivery system to deliver the photosensitizer indocyanine green, doxorubicin, and MTH1 inhibitor TH287. This nano delivery system showed combined chemo-photodynamic effects to inhibit osteosarcoma. Suppressing MTH1 protein might induce "phenotypic lethality" and enhance chemo-photodynamic therapy efficacy by improving cellular sensitivity to reactive oxygen species.

Mild microwave ablation combined with HSP90 and TGF‑β1 inhibitors enhances the therapeutic effect on osteosarcoma

Osteosarcoma is the most common malignant bone tumour and the second leading cause of cancer-related death in children and adolescents. Microwave ablation has an excellent therapeutic effect on bone tumours by instantaneously increasing the temperature in the tumour; however, there is a risk of damaging the surrounding healthy tissues by exposure to a high temperature when the treatment power is too large. In the present study, two anti-tumour reagents, a heat shock protein 90 (HSP90) inhibitor (PF-04929113) and a transforming growth factor-β1 (TGF-β1) inhibitor (SB-525334) were employed to enhance the therapeutic effect of mild-power microwave ablation. It was revealed that microwaving to 48°C combined with HSP90 and TGF-β1 inhibitors significantly increased the apoptotic rate of VX2 cells. The same results were observed during in vivo experiments using New Zealand rabbits to model osteosarcoma. In addition, the results indicated that the expression of cytochrome c, caspase-3 and caspase-9 were upregulated in response to the treatment, which indicated that the mitochondrial apoptotic signalling pathway had been activated. These findings may provide a novel strategy for the development of microwave ablation in osteosarcoma treatment, which could effectively kill tumour cells without damaging the surrounding normal tissues.

What is the best clinical approach to recurrent/refractory osteosarcoma?

Introduction: Osteosarcoma is the most common malignant bone tumor. It is currently treated with pre-and postoperative chemotherapy, associated with surgical resection of the tumor.Area covered: Relapses occur in about one in three patients presenting with localized disease, and three in four of those with metastases at diagnosis. Relapsing disease carries a very poor prognosis, with 5-year survival rates ranging between 13% and 40%.Expert opinion: Patients with unilateral lung involvement or solitary lung metastases and a recurrence-free interval (RFI) longer than 24 months have a better prognosis, and could be managed with surgical resection and close observation. Complete surgical resection of all sites of disease remains essential to survival: patients unable to achieve complete remission have a catastrophic overall survival rate. The role of second-line chemotherapy is not at all clear, and no controlled studies are available on this topic. It is worth considering for patients unable to achieve complete surgical remission, and those with multiple metastases and/or a RFI <24 months. Given their dismal prognosis, patients with multiple sites of disease not amenable to complete surgical resection should also be considered for innovative therapeutic approaches.

PLK1 Knockdown Inhibits Cell Proliferation and Cell Apoptosis, and PLK1 Is Negatively Regulated by miR-4779 in Osteosarcoma Cells

Polo-like kinase 1 (PLK1) is a ubiquitous serine/threonine protein kinase. It is reported to be involved in the occurrence and progression of various human cancers. In the present study, we explored the role and molecular mechanism of PLK1 in the proliferation of osteosarcoma (OS) cells. We found that PLK1 expression was higher in MG63/Dox cells than in MG63 cells, while inhibiting or interfering with the level of PLK1 suppressed cell proliferation of MG63/Dox cells. TargetScan analysis predicted that miR-4779 would interact with the 3'-UTR of PLK1 mRNAs and also inhibit cell autophagy of MG63/Dox cells. The data demonstrated that miR-4779 negatively regulates the expression of PLK1, and both miR-4779 and PLK1 regulate cell proliferation and cell apoptosis of MG63/Dox cells, processes that are involved in the drug resistance of OS cells.

Phase II, multi-center, open-label, single-arm clinical trial evaluating the efficacy and safety of Mycophenolate Mofetil in patients with high-grade locally advanced or metastatic osteosarcoma (ESMMO): rationale and design of the ESMMO trial

BACKGROUND

Clinical outcomes of patients with osteosarcoma remain unsatisfactory, with little improvement in a 5-year overall survival over the past three decades. There is a substantial need for further research and development to identify and develop more efficacious agents/regimens in order to improve clinical outcomes of patients for whom the prognosis is unfavorable. Recently, mycophenolate mofetil, a prodrug of mycophenolic acid, has been found to have anticancer activity against osteosarcoma in both in vitro and animal experiments, so that further investigation in humans is warranted.

METHODS

A total of 27 patients with high-grade locally advanced or metastatic osteosarcoma will be enrolled into this phase II, multi-center, open-label, single-arm, two-stage clinical trial. The main objectives of this study are to determine the efficacy and safety of mycophenolate mofetil in the patients. The primary endpoint is progression-free survival at 16 weeks; the secondary endpoints include progression-free survival, overall survival, overall response rate, safety parameters, pharmacokinetic parameters, biomarkers, pain score, and quality of life. Mycophenolate mofetil at the initial dose of 5 g/day or lower will be administered for 4 cycles (28 days/cycle) or until disease progression or unacceptable toxicity. The dose of mycophenolate mofetil may be reduced by 1-2 g/day or withheld for some Grade 3 or Grade 4 toxicities whenever clinically needed. The duration of study participation is approximately 4-5 months, with a minimum of 12 study visits. If mycophenolate mofetil proves beneficial to some patients, as evidenced by stable disease or partial response at 16 weeks, administration of mycophenolate mofetil will continue in the extension period.

DISCUSSION

This trial is the first step in the translation of therapeutic potential of mycophenolate mofetil emerging from in vitro and animal studies into the clinical domain. It is designed to assess the efficacy and safety of mycophenolate mofetil in patients with high-grade locally advanced or metastatic osteosarcoma. The results will provide important information about whether or not mycophenolate mofetil is worth further development.

TRIAL REGISTRATION

This trial was prospectively registered on Thai Clinical Trials Registry (registration number: TCTR20190701001). The posted information will be updated as needed to reflect protocol amendments and study progress.

Safety and Activity of the Combination of Ceritinib and Dasatinib in Osteosarcoma

Osteosarcoma (OS) is the second most common cause of cancer-related death in pediatric patients. The insulin-like growth factor (IGF) pathway plays a relevant role in the biology of OS but no IGF targeted therapies have been successful as monotherapy so far. Here, we tested the effect of three IGF specific inhibitors and tested ceritinib as an off-target inhibitor, alone or in combination with dasatinib, on the proliferation of seven primary OS cells. Picropodophyllin, particularly in combination with dasatinib and the combination ceritinib/dasatinib were effective in abrogating the proliferation. The ceritinib/dasatinib combination was applied to the primary cells of a 16-year-old girl with a long history of lung metastases, and was more effective than cabozantinib and olaparib. Therefore, the combination was used to treat the patient. The treatment was well tolerated, with toxicity limited to skin rush and diarrhea. A histopathological evaluation of the tumor after three months of therapy indicated regions of high necrosis and extensive infiltration of macrophages. The extension of the necrosis was proportional to the concentration of dasatinib and ceritinib in the area, as analysed by an ultra performance liquid chromatography–tandem mass spectrometer (UPLC-MS/MS). After the cessation of the therapy, radiological analysis indicated a massive growth of the patient’s liver metastases. In conclusion, these data indicate that the combination of ceritinib/dasatinib is safe and may be used to develop new therapy protocols.

Long noncoding RNA OR3A4 promotes the proliferation and invasion of osteosarcoma cells by sponging miR-1227-5p

Background

Long noncoding RNAs (lncRNAs) have been identified as key players in promoting tumourigenesis in osteosarcoma. LncRNA OR3A4 (OR3A4) has been reported as an oncogene in a number of tumours. However, the clinical value of OR3A4 in osteosarcoma and the role of OR3A4 in osteosarcoma progression are still unknown.

Methods

The expression levels of OR3A4 in the tumour tissue of osteosarcoma patients and osteosarcoma cell lines were detected by RT-PCR. Kaplan-Meier analysis and log-rank test were performed to evaluate the relationship between the level of OR3A4 expression and the prognosis of osteosarcoma patients. We investigated the association between the tissue expression levels of OR3A4 and different clinicopathological characteristics of osteosarcoma patients by χ² tests. Bioinformatic databases and luciferase reporter assays were used to predict and validate the target microRNA of OR3A4. Finally, the role of OR3A4 in the proliferation and invasion of osteosarcoma cells was tested by MTT and Transwell assays, respectively.

Results

We observed that the expression level of OR3A4 was upregulated in the tumour tissue of osteosarcoma patients (p < 0.001) and osteosarcoma cell lines (p < 0.01) compared with the normal adjacent tissue and a normal human foetal osteoblastic cell line, respectively. The survival curve revealed that patients with high expression levels of OR3A4 had lower overall survival. Increased OR3A4 expression in osteosarcoma patients was associated with distant metastasis (p = 0.02) and advanced clinical stage (p < 0.001). In addition, bioinformatics analysis and luciferase reporter assays verified the complementary binding between OR3A4 and miR-1227-5p. Furthermore, we found that OR3A4 acted as a miR-1227-5p “sponge” to modulate osteosarcoma cell proliferation and invasion via downregulation of miR-1227-5p.

Conclusion

OR3A4 promotes osteosarcoma cell proliferation and invasion by sponging miR-1227-5p, which might be related to the metastasis of osteosarcoma and could be used as a potential prognostic biomarker and therapeutic target in osteosarcoma.

A multicentric randomized phase II clinical trial evaluating high-dose thiotepa as adjuvant treatment to standard chemotherapy in patients with resectable relapsed osteosarcoma

BACKGROUND

The role of high-dose chemotherapy in relapsing osteosarcomas has not been established. We evaluated the efficacy and tolerance of high-dose thiotepa (HDTp) after standard chemotherapy (SCT) in patients with relapsed osteosarcoma.

PATIENTS AND METHODS

This randomised open-label phase II study enrolled patients 1-50 years, with local or metastatic relapse of a high-grade osteosarcoma, not progressive after two cycles of SCT, for whom a complete surgery can be achievable following treatment. The trial assigned enrolled patients in a 1:1 ratio to receive two additional courses of SCT + HDTp and autologous transplantation (Arm A), or SCT alone (Arm B). Surgery for complete resection was scheduled as soon as feasible. Primary endpoint was overall survival (OS). Secondary objectives included progression-free survival (PFS) and safety.

RESULTS

From September 2009 to November 2016, 44 patients were randomised (A:22; B:22). In total, 54.5% were males, and the median age was 16 years (9-32years). The two-year OS rate was 66.7% (95% CI 42.5-82.5) (SCT + HDTp, Arm A) versus 50.0% (95% CI 28.2-68.4) for SCT alone (Arm B). Median OS was 27.4 and 24.8 months, respectively (hazard ratio [HR] 0.826, 95% CI 0.393-1.734; p = 0.6123). Median PFS was 15.6 (8.9-24.9) months in Arm A versus 7.2 (4.8-33.3) months in Arm B, p = 0.3845. Among the 22 patients treated with SCT + HDTp, 16 (72.7%) experienced at least one grade ≥3 adverse events versus 18/22 (81.8%) patients treated with SCT. No toxic death occurred.

CONCLUSION

Adjuvant HDTp failed to significantly improve OS and PFS in resectable relapsed osteosarcomas. Despite a trend of prolonged survival and an acceptable toxicity, thiotepa cannot be recommended.

KEY MESSAGE

HDTp and autologous transplantation added to SCT did not improve OS and PFS in patients with resectable relapsed osteosarcomas. Despite a trend of prolonged survival, thiotepa cannot be recommended.

Dynasore suppresses cell proliferation, migration, and invasion and enhances the antitumor capacity of cisplatin via STAT3 pathway in osteosarcoma

Osteosarcoma (OS) is the most common malignant bone tumor. The prognosis of metastatic and recurrent OS patients still remains unsatisfactory. Cisplatin reveals undeniable anti-tumor effect while induces severe side effects that threatening patients’ health. Dynasore, a cell-permeable small molecule that inhibits dynamin activity, has been widely studied in endocytosis and phagocytosis. However, the anti-tumor effect of dynasore on OS has not yet been ascertained. In the present study, we suggested that dynasore inhibited cell proliferation, migration, invasion, and induced G0/G1 arrest of OS cells. Besides, dynasore repressed tumorigenesis of OS in xenograft mouse model. In addition, we demonstrated that dynasore improved the anti-tumor effect of cisplatin in vitro and in vivo without inducing nephrotoxicity and hepatotoxicity. Mechanistically, dynasore repressed the expression of CCND1, CDK4, p-Rb, and MMP-2. Furthermore, we found that dynasore exerts anti-tumor effects in OS partially via inhibiting STAT3 signaling pathway but not ERK-MAPK, PI3K-Akt or SAPK/JNK pathways. P38 MAPK pathway served as a negative regulatory mechanism in dynasore induced anti-OS effects. Taken together, our study indicated that dynasore does suppress cell proliferation, migration, and invasion via STAT3 signaling pathway, and enhances the antitumor capacity of cisplatin in OS. Our results suggest that dynasore is a novel candidate drug to inhibit the tumor growth of OS and enhance the anti-tumor effects of cisplatin.

GREM1 overexpression inhibits proliferation, migration and angiogenesis of osteosarcoma

Osteosarcoma is the most common malignancy of bone that occurs in young adults and children, with a five-year survival rate of 60-70%. Metastasis of osteosarcoma maintains an even poorer prognosis. GREM1 plays an important role in regulating organogenesis, body patterning, and tissue differentiation. However, there are limited studies on GREM1 in osteosarcomas. This study was carried out to characterize the expression and function of GREM1 in osteosarcoma cells, thus extending our understanding of osteosarcoma metastasis. GREM1 expression was detected in hBMSC, hFOB1.19, Saos-2, MG63 and U2OS cell lines using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. Gain- and loss-of-function approaches were used to assess the biological function of GREM1 in U2OS cells. The effects of GREM1 on U2OS cell proliferation were examined using the CCK-8 and colony formation assay. Migration and invasion ability were confirmed by the wound healing and Transwell assay, respectively. Flow cytometry was used to analyse the effect of GREM1 on the cell cycle and apoptosis. The expression of GREM1 targets was evaluated by qRT-PCR and western blotting. The expression of GREM1 was significantly downregulated in osteosarcoma. GREM1 overexpression inhibited the proliferation, migration and invasion of U2OS cells. GREM1 overexpression suppressed tumour cell-induced endothelial cell migration and invasion ability. The effect of GREM1 may be transduced through regulation of the BMP target transcription factor inhibitor of MMP-2 and -9 as well as Id1. GREM1 overexpression and knockdown regulates the tumorigenesis of osteosarcoma in vivo. In conclusion, GREM1 is downregulated in osteosarcoma cells, and overexpression of GREM1 inhibits the proliferation, migration, invasion and angiogenesis abilities of osteosarcoma cells in vitro and in vivo.

An update on emerging drugs in osteosarcoma: towards tailored therapies?

Introduction: Current treatment of conventional and non-conventional high-grade osteosarcoma (HGOS) is based on the surgical removal of primary tumor and, when possible, of metastases and local reccurrence, together with systemic pre- and post-operative chemotherapy with drugs that have been used since decades. Areas covered: This review is intended to summarize the new agents and therapeutic strategies that are under clinical evaluation in HGOS, with the aim to increase the cure probability of this highly malignant bone tumor, which has not significantly improved during the last 30-40 years. The list of drugs, compounds and treatment modalities presented and discussed here has been generated by considering only those that are included in presently ongoing and recruiting clinical trials, or which have been completed in the last 2 years with reported results, on the basis of the information obtained from different and continuously updated databases. Expert opinion: Despite HGOS is a rare tumor, several clinical trials are presently evaluating different treatment strategies, which may hopefully positively impact on the outcome of patients who experience unfavorable prognosis when treated with conventional therapies.

Overexpression of FER1L4 promotes the apoptosis and suppresses epithelial-mesenchymal transition and stemness markers via activating PI3K/AKT signaling pathway in osteosarcoma cells

Novel long non-coding RNA Fer-1-like protein 4 (FER1L4) has been identified as a tumor suppressor in endometrial carcinoma, ovarian cancer, hepatocellular carcinoma, esophageal squamous cell carcinoma. However, the function of FER1L4 in osteosarcoma has not been clear. The aim of the research was to explore the effects of FER1L4 in osteosarcoma. Results showed that FER1L4 was observed to be lowly expressed in osteosarcoma cell lines (US-O2, MG-63 and SaOS-2 cells), especially MG63 cells. Besides, overexpression of FER1L4 remarkably repressed the proliferation, migration and invasion of MG63 cells. FER1L4-induced apoptotic cell death leaded to the activation of caspase-3 and Bax/Bcl2. Moreover, epithelial-mesenchymal transition (EMT) was tremendously suppressed by increased FER1L4, evidences were the increased E-cadherin and reduced vimentin and fibronectin. Blocking FER1L4 expression by sh-FER1L4 treatment increased the expression of SOX9, CD44, ALDH1, Nanog and Oct4, indicating that FER1L4 could effectively decrease cell stemness in osteosarcoma. Furthermore, the protein levels of p-AKT and p-PI3K were remarkably suppressed when FER1L4 was knocked down. In conclusion, the study indicated that FER1L4 acted as a tumor suppressor in osteosarcoma via activating PI3K/AKT pathway may be a new prognostic biomarker and potential therapeutic target for osteosarcoma intervention.

Efficacy and safety of regorafenib in adult patients with metastatic osteosarcoma: a non-comparative, randomised, double-blind, placebo-controlled, phase 2 study

BACKGROUND

Regorafenib has proven activity in patients with pretreated gastrointestinal stromal tumours and colorectal and hepatocellular carcinoma. We designed REGOBONE to assess the efficacy and safety of regorafenib for patients with progressive metastatic osteosarcoma and other bone sarcomas. This trial comprised four parallel independent cohorts: osteosarcoma, Ewing sarcoma, chondrosarcoma, and chordoma. In this Article, we report the results of the osteosarcoma cohort.

METHODS

In this non-comparative, double-blind, placebo-controlled, phase 2 trial, patients aged 10 years or older with histologically confirmed osteosarcoma whose disease had progressed after treatment with one to two previous lines of chemotherapy for metastatic disease and an Eastern Cooperative Oncology Group performance status of 0 or 1 were enrolled. Patients were randomly assigned (2:1) to receive either oral regorafenib (160 mg/day, for 21 of 28 days) or matching placebo. Patients in both groups also received best supportive care. Randomisation was done using a web-based system and was stratified (permuted block) by age at inclusion (<18 vs ≥18 years old). Investigators and patients were masked to treatment allocation. Patients in the placebo group, after centrally confirmed progressive disease, could cross over to receive regorafenib. The primary endpoint was the proportion of patients without disease progression at 8 weeks. Analyses were done by modified intention to treat (ie, patients without any major entry criteria violation who initiated masked study drug treatment were included). All participants who received at least one dose of study drug were included in the safety analyses. This study is registered with ClinicalTrials.gov, number NCT02389244, and the results presented here are the final analysis of the osteosarcoma cohort (others cohorts are ongoing).

FINDINGS

Between Oct 10, 2014, and April 4, 2017, 43 adult patients were enrolled from 13 French comprehensive cancer centres. All patients received at least one dose of assigned treatment and were evaluable for safety; five patients were excluded for major protocol violations (two in the placebo group and three in the regorafenib group), leaving 38 patients who were evaluable for efficacy (12 in the placebo group and 26 in the regorafenib group). 17 of 26 patients (65%; one-sided 95% CI 47%) in the regorafenib group were non-progressive at 8 weeks compared with no patients in the placebo group. Ten patients in the placebo group crossed over to receive open-label regorafenib after centrally confirmed disease progression. 13 treatment-related serious adverse events occurred in seven (24%) of 29 patients in the regorafenib group versus none of 14 patients in the placebo group. The most common grade 3 or worse treatment-related adverse events during the double-blind period of treatment included hypertension (in seven [24%] of 29 patients in the regorafenib group vs none in the placebo group), hand-foot skin reaction (three [10%] vs none), fatigue (three [10%] vs one [3%]), hypophosphataemia (three [10%] vs none), and chest pain (three [10%] vs none). No treatment-related deaths occurred.

INTERPRETATION

Regorafenib demonstrated clinically meaningful antitumour activity in adult patients with recurrent, progressive, metastatic osteosarcoma after failure of conventional chemotherapy, with a positive effect on delaying disease progression. Regorafenib should be further evaluated in the setting of advanced disease as well as potentially earlier in the disease course for patients at high risk of relapse. Regorafenib might have an important therapeutic role as an agent complementary to standard cytotoxic chemotherapy in the therapeutic armamentarium against osteosarcoma.

FUNDING

Bayer HealthCare.

Role of the HDAC6/STAT3 pathway in regulating PD-L1 expression in osteosarcoma cell lines

Histone deacetylases (HDACs), initially described as histone modifiers, have more recently been verified to target various other proteins unrelated to the chromatin environment. On this basis, findings of the current study demonstrates that the pharmacological or genetic abrogation of HDAC6 in osteosarcoma cell lines down-regulates the expression of program death receptor ligand-1 (PD-L1), an important co-stimulatory molecule expressed in cancer cells, which activates the inhibitory regulatory pathway PD-1 in T cells. As shown by our results, the mechanism by which HDAC6 regulated PD-L1 expression was mediated by the transcription factor STAT3. In addition, we observed that selective HDAC6 inhibitors could inhibit tumor progression in vivo. Crucially, these results provide an essential pre-clinical rationale and justification for the necessity of further research on HDAC6 inhibitors as potential immuno-modulatory agents in osteosarcoma.

Current status of immunotherapy for sarcomas

Although the development of anticancer drugs has improved the outcomes of bone and soft tissue sarcomas, the clinical outcome of patients with relapsed sarcomas remains unsatisfactory due to therapeutic toxicities and resistance to anticancer drugs. Therefore, novel therapeutic modalities are needed to improve the outcome of patients with bone and soft tissue sarcomas. Dendritic cells present tumor antigens and stimulate immune responses, and immune cells, such as cytotoxic T lymphocytes, kill tumor cells by recognizing tumor antigens. However, immune-suppressive conditions by immune regulator PD-1, CTLA-4 and regulatory T cells help tumor growth and progression. In this report, current immunotherapies including cellular immunotherapy and checkpoint inhibitors are introduced, and the advantages and disadvantages of the treatments are discussed.

Serum Antibodies Against Simian Virus 40 Large T Antigen, the Viral Oncoprotein, in Osteosarcoma Patients

Human osteosarcoma (OS) is a rare human cancer, mostly occurring in children and adolescents. Simian virus 40 (SV40 = Macaca mulatta polyomavirus 1) sequences have been detected in different human cancers, including osteosarcoma. SV40 is an oncogenic virus in vivo, whereas it transforms different kinds of mammalian cells, as well as distinct human cell types. SV40 injected in rodents induces tumors of different histotypes, such as bone and brain tumors. Herein, the association between OS and SV40 large T antigen (Tag) was studied by employing indirect ELISAs using synthetic peptides that mimic different epitopes of the SV40 Tag, the viral oncoprotein. Indirect ELISAs were used to detect serum IgG antibodies against this oncogenic virus in samples from OS patients. Controls were sera from healthy subjects (HS) and oncological patients affect by breast cancer (BC), which is not associated with SV40. It turned out that sera of OS patients had a higher prevalence of SV40 Tag antibodies, 35%, compared to HS, 20% and BC, 19%, respectively. The different prevalence of SV40 Tag antibodies revealed in OS vs. HS and vs. BC is statistically significant with P < 0.05 and P < 0.01, respectively. Our immunological data indicate a significantly higher prevalence of antibodies against SV40 Tag epitopes in serum samples from OS patients compared to HS and BC, the controls. These results suggest an association between OS and SV40 Tag, indicating that this oncogenic virus may be a cofactor in OS development.

Establishment and characterization of in vivo orthotopic bioluminescent xenograft models from human osteosarcoma cell lines in Swiss nude and NSG mice

Osteosarcoma is one of the most common primary bone tumors in childhood and adolescence. Metastases occurrence at diagnosis or during disease evolution is the main therapeutic challenge. New drug evaluation to improve patient survival requires the development of various preclinical models mimicking at best the complexity of the disease and its metastatic potential. We describe here the development and characteristics of two orthotopic bioluminescent (Luc/mKate2) cell‐derived xenograft (CDX) models, Saos‐2‐B‐Luc/mKate2‐CDX and HOS‐Luc/mKate2‐CDX, in different immune (nude and NSG mouse strains) and bone (intratibial and paratibial with periosteum activation) contexts. IVIS SpectrumCT system allowed both longitudinal computed tomography (CT) and bioluminescence real‐time follow‐up of primary tumor growth and metastatic spread, which was confirmed by histology. The murine immune context influenced tumor engraftment, primary tumor growth, and metastatic spread to lungs, bone, and spleen (an unusual localization in humans). Engraftment in NSG mice was found superior to that found in nude mice and intratibial bone environment more favorable to engraftment compared to paratibial injection. The genetic background of the two CDX models also led to distinct primary tumor behavior observed on CT scan. Saos‐2‐B‐Luc/mKate2‐CDX showed osteocondensed, HOS‐Luc/mKate2‐CDX osteolytic morphology. Bioluminescence defined a faster growth of the primary tumor and metastases in Saos‐2‐B‐Luc/mKate2‐CDX than in HOS‐Luc/mKate2‐CDX. The early detection of primary tumor growth and metastatic spread by bioluminescence allows an improved exploration of osteosarcoma disease at tumor progression, and metastatic spread, as well as the evaluations of anticancer treatments. Our orthotopic models with metastatic spread bring complementary information to other types of existing osteosarcoma models.

Genetic Polymorphisms of Insulin-Like Growth Factor 1 Are Associated with Osteosarcoma Risk and Prognosis

Background

Insulin-like growth factor 1 (IGF-1) gene plays an important role in bone and soft tumors. IGF-1 gene polymorphisms have been revealed to be correlated with the carcinogenesis and progression of solid malignancies. We therefore hypothesized that IGF-1 genetic polymorphisms might be associated with the risks and outcomes of osteosarcomas in Chinese individuals.

Material/Methods

This study included 173 conventional osteosarcoma individuals and 175 tumor-free controls. Five single nucleotide polymorphisms (SNPs) of IGF-1 (rs6214, rs6218, rs35767, rs5742612, and rs5742714) were genotyped. DNA was extracted from peripheral blood and analyzed for SNP genotyping using PCR.

Results

We found that rs6218 had a predictive role for the susceptibility and progression of osteosarcoma. The presence of TC and CC genotypes of rs6218 indicated higher risk of osteosarcoma. In addition, rs6218 TC and CC genotypes were discovered to be associated with later stage and elevated risk of osteosarcoma metastasis.

Conclusions

IGF-1 polymorphisms are potential prognostic predictors of osteosarcoma susceptibility and outcomes.

LncRNA, CRNDE promotes osteosarcoma cell proliferation, invasion and migration by regulating Notch1 signaling and epithelial-mesenchymal transition

Osteosarcoma is the most common bone malignancy in adolescence. Recently, the long non-coding RNAs (lncRNAs) were reported to play important roles in osteosarcoma progression. The present study examined the potential role of the lncRNA, Colorectal Neoplasia Differentially Expressed (CRNDE) and molecular mechanisms underlying osteosarcoma progression. In the present study, we identified that CRNDE was up-regulated in osteosarcoma tissues and cell lines, and CRNDE expression level was significantly higher in osteosarcoma tissues from patients with advanced stage and metastasis. Overexpression of CRNDE promoted cell growth, cell proliferation, cell invasion and migration, and increased cell population at S phase with a decreased cell population at G₀/G₁ phase in MG-63 cells. Knock-down of CRNDE suppressed cell growth, cell proliferation, cell invasion and migration, and decreased cell population at S phase with an increased cell population at G₀/G₁ phase in U2OS cells. Overexpression of CRNDE was found to enhance the activity of Notch1 signaling and promote epithelial-mesenchymal transition (EMT) in MG-63 cells, while knock-down of CRNDE exerted the opposite effects in U2OS cells. The in vivo results showed that knock-down of CRNDE suppressed the tumor growth in the nude mice inoculated with osteosarcoma cells, and knock-down of CRNDE also suppressed the mRNA expression of Notch1, JAG1, N-cadherin, vimentin, and increased the mRNA expression of E-cadherin in the tumor tissues. Collectively, our results indicated that CRNDE functioned as an oncogene in osteosarcoma cell lines, and CRNDE may exert its oncogenic role via regulating Notch1 signaling and EMT in osteosarcoma.