A phase II trial evaluating the feasibility of adding bevacizumab to standard osteosarcoma therapy

Artificial intelligence-based radiomics in bone tumors: Technical advances and clinical application

Radiomics is the extraction of predefined mathematic features from medical images for predicting variables of clinical interest. Recent research has demonstrated that radiomics can be processed by artificial intelligence algorithms to reveal complex patterns and trends for diagnosis, and prediction of prognosis and response to treatment modalities in various types of cancer. Artificial intelligence tools can utilize radiological images to solve next-generation issues in clinical decision making. Bone tumors can be classified as primary and secondary (metastatic) tumors. Osteosarcoma, Ewing sarcoma, and chondrosarcoma are the dominating primary tumors of bone. The development of bone tumor model systems and relevant research, and the assessment of novel treatment methods are ongoing to improve clinical outcomes, notably for patients with metastases. Artificial intelligence and radiomics have been utilized in almost full spectrum of clinical care of bone tumors. Radiomics models have achieved excellent performance in the diagnosis and grading of bone tumors. Furthermore, the models enable to predict overall survival, metastases, and recurrence. Radiomics features have exhibited promise in assisting therapeutic planning and evaluation, especially neoadjuvant chemotherapy. This review provides an overview of the evolution and opportunities for artificial intelligence in imaging, with a focus on hand-crafted features and deep learning-based radiomics approaches. We summarize the current application of artificial intelligence-based radiomics both in primary and metastatic bone tumors, and discuss the limitations and future opportunities of artificial intelligence-based radiomics in this field. In the era of personalized medicine, our in-depth understanding of emerging artificial intelligence-based radiomics approaches will bring innovative solutions to bone tumors and achieve clinical application.

Targeting signaling pathways in osteosarcoma: Mechanisms and clinical studies

Osteosarcoma (OS) is a highly prevalent bone malignancy among adolescents, accounting for 40% of all primary malignant bone tumors. Neoadjuvant chemotherapy combined with limb-preserving surgery has effectively reduced patient disability and mortality, but pulmonary metastases and OS cells' resistance to chemotherapeutic agents are pressing challenges in the clinical management of OS. There has been an urgent need to identify new biomarkers for OS to develop specific targeted therapies. Recently, the continued advancements in genomic analysis have contributed to the identification of clinically significant molecular biomarkers for diagnosing OS, acting as therapeutic targets, and predicting prognosis. Additionally, the contemporary molecular classifications have revealed that the signaling pathways, including Wnt/β-catenin, PI3K/AKT/mTOR, JAK/STAT3, Hippo, Notch, PD-1/PD-L1, MAPK, and NF-κB, have an integral role in OS onset, progression, metastasis, and treatment response. These molecular classifications and biological markers have created new avenues for more accurate OS diagnosis and relevant treatment. We herein present a review of the recent findings for the modulatory role of signaling pathways as possible biological markers and treatment targets for OS. This review also discusses current OS therapeutic approaches, including signaling pathway-based therapies developed over the past decade. Additionally, the review covers the signaling targets involved in the curative effects of traditional Chinese medicines in the context of expression regulation of relevant genes and proteins through the signaling pathways to inhibit OS cell growth. These findings are expected to provide directions for integrating genomic, molecular, and clinical profiles to enhance OS diagnosis and treatment.

Deciphering the Signaling Mechanisms of Osteosarcoma Tumorigenesis

Osteosarcoma (OS) is the predominant primary bone tumor in the pediatric and adolescent populations. It has high metastatic potential, with the lungs being the most common site of metastasis. In contrast to many other sarcomas, OS lacks conserved translocations or genetic mutations; instead, it has heterogeneous abnormalities, including somatic DNA copy number alteration, ploidy, chromosomal amplification, and chromosomal loss and gain. Unfortunately, clinical outcomes have not significantly improved in over 30 years. Currently, no effective molecularly targeted therapies are available for this disease. Several genomic studies showed inactivation in the tumor suppressor genes, including p53, RB, and ATRX, and hyperactivation of the tumor promoter genes, including MYC and MDM2, in OS. Alterations in the major signaling pathways, including the PI3K/AKT/mTOR, JAK/STAT, Wnt/β-catenin, NOTCH, Hedgehog/Gli, TGF-β, RTKs, RANK/RANKL, and NF-κB signaling pathways, have been identified in OS development and metastasis. Although OS treatment is currently based on surgical excision and systematic multiagent therapies, several potential targeted therapies are in development. This review focuses on the major signaling pathways of OS, and we propose a biological rationale to consider novel and targeted therapies in the future.

Prospects and Advances in Adoptive Natural Killer Cell Therapy for Unmet Therapeutic Needs in Pediatric Bone Sarcomas

Malignant bone tumors are aggressive tumors, with a high tendency to metastasize, that are observed most frequently in adolescents during rapid growth spurts. Pediatric patients with malignant bone sarcomas, Ewing sarcoma and osteosarcoma, who present with progressive disease have dire survival rates despite aggressive therapy. These therapies can have long-term effects on bone growth, such as decreased bone mineral density and reduced longitudinal growth. New therapeutic approaches are therefore urgently needed for targeting pediatric malignant bone tumors. Harnessing the power of the immune system against cancer has improved the survival rates dramatically in certain cancer types. Natural killer (NK) cells are a heterogeneous group of innate effector cells that possess numerous antitumor effects, such as cytolysis and cytokine production. Pediatric sarcoma cells have been shown to be especially susceptible to NK-cell-mediated killing. NK-cell adoptive therapy confers numerous advantages over T-cell adoptive therapy, including a good safety profile and a lack of major histocompatibility complex restriction. NK-cell immunotherapy has the potential to be a new therapy for pediatric malignant bone tumors. In this manuscript, we review the general characteristics of osteosarcoma and Ewing sarcoma, discuss the long-term effects of sarcoma treatment on bones, and the barriers to effective immunotherapy in bone sarcomas. We then present the laboratory and clinical studies on NK-cell immunotherapy for pediatric malignant bone tumors. We discuss the various donor sources and NK-cell types, the engineering of NK cells and combinatorial treatment approaches that are being studied to overcome the current challenges in adoptive NK-cell therapy, while suggesting approaches for future studies on NK-cell immunotherapy in pediatric bone tumors.

Targeted therapy for osteosarcoma: a review

BACKGROUND

Osteosarcoma is a common primary malignant tumour of the bone that usually occurs in children and adolescents. It is characterised by difficult treatment, recurrence and metastasis, and poor prognosis. Currently, the treatment of osteosarcoma is mainly based on surgery and auxiliary chemotherapy. However, for recurrent and some primary osteosarcoma cases, owing to the rapid progression of disease and chemotherapy resistance, the effects of chemotherapy are poor. With the rapid development of tumour-targeted therapy, molecular-targeted therapy for osteosarcoma has shown promise.

PURPOSE

In this paper, we review the molecular mechanisms, related targets, and clinical applications of targeted osteosarcoma therapy. In doing this, we provide a summary of recent literature on the characteristics of targeted osteosarcoma therapy, the advantages of its clinical application, and development of targeted therapy in future. We aim to provide new insights into the treatment of osteosarcoma.

CONCLUSION

Targeted therapy shows potential in the treatment of osteosarcoma and may offer an important means of precise and personalised treatment in the future, but drug resistance and adverse effects may limit its application.

Research of the Active Components and Potential Mechanisms of Qingfei Gujin Decoction in the Treatment of Osteosarcoma Based on Network Pharmacology and Molecular Docking Technology

Aim. Qingfei Gujin Decoction (QGD) has been shown to be effective against osteosarcoma. This research was aimed at investigating the main active ingredients and potential mechanisms of QGD acting on osteosarcoma through network pharmacology and molecular docking techniques. Methods. The active ingredients and targets of QGD were screened from the TCMSP database, and the predicted targets were obtained from the PharmMapper database. Meanwhile, the targets of osteosarcoma were collected using OMIM, PharmGKB, and DisGeNET databases. Then, GO and KEGG enrichment analyses were performed by RStudio. PPI and drug-ingredient-target networks were constructed using Cytoscape 3.2.1 to screen the major active ingredients, key networks, and targets. Finally, molecular docking of key genes and their regulatory active ingredients was performed using AutoDockTools 1.5.6 software. Results. 38 active ingredients were collected, generating 89 cross-targets; quercetin, luteolin, β-sitosterol, and kaempferol were the main active ingredients of QGD acting on osteosarcoma, and major signaling pathways such as PI3K-Akt signaling pathway, MAPK signaling pathway, and IL-17 signaling pathway were observed. TP53, SRC, and ESR1 were identified as key proteins that docked well with their regulated compounds. Conclusion. QGD is effective against osteosarcoma through multicomponent, multitarget, and multipathway. This study was helpful for finding effective targets and compounds for osteosarcoma treatment.

Receptor Tyrosine Kinase Inhibitors for the Treatment of Recurrent and Unresectable Bone Sarcomas

Bone sarcomas are a heterogeneous group of rare tumors with a predominance in the young population. Few options of systemic treatment are available once they become unresectable and resistant to conventional chemotherapy. A better knowledge of the key role that tyrosine kinase receptors (VEGFR, RET, MET, AXL, PDGFR, KIT, FGFR, IGF-1R) may play in the pathogenesis of these tumors has led to the development of multi-target inhibitors (TKIs) that are progressively being incorporated into our therapeutic arsenal. Osteosarcoma (OS) is the most frequent primary bone tumor and several TKIs have demonstrated clinical benefit in phase II clinical trials (cabozantinib, regorafenib, apatinib, sorafenib, and lenvatinib). Although the development of TKIs for other primary bone tumors is less advanced, preclinical data and early trials have begun to show their potential benefit in advanced Ewing sarcoma (ES) and rarer bone tumors (chondrosarcoma, chordoma, giant cell tumor of bone, and undifferentiated pleomorphic sarcoma). Previous reviews have mainly provided information on TKIs for OS and ES. We aim to summarize the existing knowledge regarding the use of TKIs in all bone sarcomas including the most recent studies as well as the potential synergistic effects of their combination with other systemic therapies.

Effects of microenvironment in osteosarcoma on chemoresistance and the promise of immunotherapy as an osteosarcoma therapeutic modality

Osteosarcoma (OS) is one of the most common primary malignant tumors originating in bones. Its high malignancy typically manifests in lung metastasis leading to high mortality. Although remarkable advances in surgical resection and neoadjuvant chemotherapy have lengthened life expectancy and greatly improved the survival rate among OS patients, no further breakthroughs have been achieved. It is challenging to treat patients with chemoresistant tumors and distant metastases. Recent studies have identified a compelling set of links between hypoxia and chemotherapy failure. Here, we review the evidence supporting the positive effects of hypoxia in the tumor microenvironment (TME). In addition, certain anticancer effects of immune checkpoint inhibitors have been demonstrated in OS preclinical models. Continued long-term observation in clinical trials is required. In the present review, we discuss the mutualistic effects of the TME in OS treatment and summarize the mechanisms of immunotherapy and their interaction with TME when used to treat OS. We also suggest that immunotherapy, a new comprehensive and potential antitumor approach that stimulates an immune response to eliminate tumor cells, may represent an innovative approach for the development of a novel treatment regimen for OS patients.

Origin and Therapies of Osteosarcoma

Simple Summary

Osteosarcoma is the most common malignant bone tumor in children, with a 5-year survival rate ranging from 70% to 20% depending on the aggressiveness of the disease. The current treatments have not evolved over the past four decades due in part to the genetic complexity of the disease and its heterogeneity. This review will summarize the current knowledge of OS origin, diagnosis and therapies.

Abstract

Osteosarcoma (OS) is the most frequent primary bone tumor, mainly affecting children and young adults. Despite therapeutic advances, the 5-year survival rate is 70% but drastically decreases to 20–30% for poor responders to therapies or for patients with metastasis. No real evolution of the survival rates has been observed for four decades, explained by poor knowledge of the origin, difficulties related to diagnosis and the lack of targeted therapies for this pediatric tumor. This review will describe a non-exhaustive overview of osteosarcoma disease from a clinical and biological point of view, describing the origin, diagnosis and therapies.

Targeting tumor microenvironment and metastasis in children with solid tumors

PURPOSE OF REVIEW

The prognosis of pediatric patients with metastatic solid tumors remains poor, necessitating development of novel therapeutic strategies. The biology of the pediatric tumor microenvironment (TME) presents obstacles for the efficacy of current therapeutic approaches including immunotherapies. Targeting various aspects of the TME in pediatric patients with solid tumors represents a therapeutic opportunity that may improve outcomes. Here we will discuss recent advances in characterization of the TME, and clinical advances in targeting the immune, vascular, and stromal aspects of the TME.

RECENT FINDINGS

Although immunotherapies have shown limited success in the treatment of pediatric solid tumor patients thus far, optimization of these approaches to overcome the TME shows promise. In addition, there is increasing focus on the myeloid compartment as a therapeutic target. Vascular endothelial growth factor (VEGF) targeting has resulted in responses in some refractory pediatric solid tumors. There has been relatively little focus on stromal targeting; however, emerging preclinical data are improving our understanding of underlying biology, paving the way for future therapies.

SUMMARY

Although translation of TME-targeting therapies for pediatric solid tumors is in the early stages, we are optimistic that continued exploration of approaches aimed at rebalancing the TME will lead to improved outcomes for this population.

Immunotherapies for Pediatric Solid Tumors: A Targeted Update

There are encouraging signs in our collective progress to leverage the immune system to treat pediatric cancers. Here, we summarize interim successes in cancer immunotherapy and opportunities to translate from the adult world to pediatrics, and highlight challenges that could benefit from additional development, focusing on solid tumors. Just a decade ago, other than antibodies targeting disialoganglioside (GD2) in neuroblastoma, pediatric cancer immunotherapy was mostly relegated to obscure preclinical studies in a few academic labs. Today there are numerous clinical trials of a variety of antibody, cellular, gene, and viral therapies and vaccines designed to either promote antitumor immunity or specifically attack validated immunotherapy targets. Understanding those targets and their pediatric relevance is paramount. While much work is underway to evaluate the utility of numerous immunologic targets, the lack of regulatory approvals is emblematic of the challenges that remain. Herein we focus our review on the most promising targeted immunotherapies in clinical trials for children.

Current research progress in targeted anti-angiogenesis therapy for osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumour with a peak in incidence during adolescence. Delayed patient presentation and diagnosis is common with approximately 15% of OS patients presenting with metastatic disease at initial diagnosis. With the introduction of neoadjuvant chemotherapy in the 1970s, disease prognosis improved from 17% to 60%-70% 5-year survival, but outcomes have not significantly improved since then. Novel and innovative therapeutic strategies are urgently needed as an adjunct to conventional treatment modalities to improve outcomes for OS patients. Angiogenesis is crucial for tumour growth, metastasis and invasion, and its prevention will ultimately inhibit tumour growth and metastasis. Dysregulation of angiogenesis in bone microenvironment involving osteoblasts and osteoclasts might contribute to OS development. This review summarizes existing knowledge regarding pre-clinical and developmental research of targeted anti-angiogenic therapy for OS with the aim of highlighting the limitations associated with this application. Targeted anti-angiogenic therapies include monoclonal antibody to VEGF (bevacizumab), tyrosine kinase inhibitors (Sorafenib, Apatinib, Pazopanib and Regorafenib) and human recombinant endostatin (Endostar). However, considering the safety and efficacy of these targeted anti-angiogenesis therapies in clinical trials cannot be guaranteed at this point, further research is needed to completely understand and characterize targeted anti-angiogenesis therapy in OS.

Receptor tyrosine kinase inhibitors for the treatment of osteosarcoma and Ewing sarcoma

Adjuvant chemotherapy for osteosarcoma and Ewing sarcoma consists of conventional cytotoxic regimens that have changed little over the past decades. There is an urgent need for agents that are more effective and have less long-term toxicity. Receptor tyrosine kinases regulate cell growth and proliferation of these tumors, and small-molecule inhibitors for many of these kinases are now available. In this article, we review published phase II trials for patients with recurrent disease and highlight the pathways targeted by available agents, as well as the toxicity and efficacy results seen to date. We also discuss the difficulties in identifying biomarkers to facilitate rational patient selection, as well as published and proposed strategies for how these inhibitors can be combined with conventional chemotherapy or other targeted agents. It is hoped future trials can capitalize on this growing experience to optimize the use of this exciting class of agents.

Pursuing Precision: Receptor Tyrosine Kinase Inhibitors for Treatment of Pediatric Solid Tumors

Receptor tyrosine kinases are critical for the growth and proliferation of many different cancers and therefore represent a potential vulnerability that can be therapeutically exploited with small molecule inhibitors. Over forty small molecule inhibitors are currently approved for the treatment of adult solid tumors. Their use has been more limited in pediatric solid tumors, although an increasing number of single-agent and combination studies are now being performed. These agents have been quite successful in certain clinical contexts, such as the treatment of pediatric tumors driven by kinase fusions or activating mutations. By contrast, only modest activity has been observed when inhibitors are used as single agents for solid tumors that do not have genetically defined alterations in the target genes. The absence of predictive biomarkers has limited the wider applicability of these drugs and much work remains to define the appropriate patient population and clinical situation in which receptor tyrosine kinase inhibitors are most beneficial. In this manuscript, we discuss these issues by highlighting past trials and identifying future strategies that may help add precision to the use of these agents for pediatric extracranial solid tumors.

223-Radium for metastatic osteosarcoma: combination therapy with other agents and external beam radiotherapy

Background

Bone-seeking radiopharmaceuticals can deposit radiation selectively to some osteosarcoma tumours because of the bone-forming nature of this cancer.

Objectives

This is the first report of using 223-radium, an alpha-emitting calcium analogue with a high therapeutic index, in combination therapy with other agents in 15 patients with metastatic osteoblastic osteosarcoma.

Methods

Candidates for alpha-radiotherapy if ^99mTc-MDP bone scan had avid bone-forming lesions and no therapy of higher priority (eg, definitive surgery). Monthly 223-radium infusions (1.49 μCi/kg or 55.13 kBq/kg) were given.

Results

The median infusion number was three and the average time to progression was 4.3 months for this cohort receiving 223-radium+other agents. Agents provided during 223-radium included (1) drugs to reduce skeletal complications: monthly denosumab (n=13) or zolendronate (n=1); (2) agents with antivascular endothelial growth factor activity, pazopanib (n=8) or sorafenib (n=1), (3) alkylating agents: oral cyclophosphamide (n=1) or ifosfamide, given as a 14-day continuous infusion (n=1, two cycles), (4) high-dose methotrexate (n=1), pegylated liposomal doxorubicin (n=1); and (5) two other combinations: nivolumab and everolimus (n=1) and rapamycin and auranofin (n=1). Radiation therapy, including stereotactic body radiotherapy (SBRT), was also given to 11 patients concurrently with 223-radium (n=2), after 223-radium completion (n=3), or both concurrently and then sequentially for other sites (n=6). After 223-radium infusions, patients without RT had a median overall survival of 4.3 months compared with those with SBRT and/or RT, who had a median overall survival of 13.5 months.

Conclusion Although only 1/15 of patients with osteoblastic osteosarcoma still remain alive after 223-radium, overall survival

Prognostic and Therapeutic Utility of Variably Expressed Cell Surface Receptors in Osteosarcoma

Background

Six cell surface receptors, human epidermal growth factor receptor-2 (Her-2), platelet-derived growth factor receptor-β (PDGFR-β), insulin-like growth factor-1 receptor (IGF-1R), insulin receptor (IR), c-Met, and vascular endothelial growth factor receptor-3 (VEGFR-3), previously demonstrated variable expression across varying patient-derived and standard osteosarcoma (OS) cell lines. The current study sought to validate previous expression patterns and evaluate whether these receptors offer prognostic and/or therapeutic value.

Methods

Patient-derived OS cell lines (n = 52) were labeled with antibodies to Her-2, PDGFR-β, IGF-1R, IR, c-Met, and VEGFR-3. Expression was characterized using flow cytometry. The difference in geometric mean fluorescent intensity (geoMFI_diff = geoMFI_positive - geoMFI_negative) was calculated for each receptor across all cell lines. Receptor expression was categorized as low (Q1), intermediate (Q2, Q3), or high (Q4). The event-free survival (EFS) and overall survival for the six cell surface receptors were estimated by the Kaplan-Meier method. Differences in hazard for EFS event and overall survival event for patients in each of the three expression levels in each of the six cell surface receptors were assessed using the log-rank test.

Results

All 6 receptors were variably expressed in the majority of cell lines. IR and PDGFR-β expressions were found to be significant predictors for EFS amongst patients with nonmetastatic disease (p=0.02 and 0.01, respectively). The hazard ratio for EFS was significantly higher between high IR and intermediate IR expression (HR = 2.66, p=0.02), as well as between high PDGFR-β and intermediate PDGFR-β expression (HR = 5.68, p=0.002). Her-2, c-Met, IGF-1R, and VEGFR-3 were not found to be significant predictors for either EFS or overall survival.

Conclusion

The six cell surface receptors demonstrated variable expression across the majority of patient-derived OS cell lines tested. Limited prognostic value was offered by IR and PDGFR-β expression within nonmetastatic patients. The remaining receptors do not provide clear prognostic utility. Nevertheless, their consistent, albeit variable, surface expression across a large panel of patient-derived OS cell lines maintains their potential use as future therapeutic targets.

Use of Antiangiogenic Therapies in Pediatric Solid Tumors

Cancer is an important cause of death in childhood. In recent years, scientists have made an important effort to achieve greater precision and more personalized treatments against cancer. But since only a few pediatric patients have identifiable therapeutic targets, other ways to stop the neoplastic cell proliferation and dissemination are needed. Therefore, the inhibition of general processes involved in the growth and behavior of tumors can be a relevant strategy for the development of new cancer therapies. In the case of solid tumors, one of these processes is angiogenesis, essential for tumor growth and generation of metastases. This review summarizes the results obtained with the use of antiangiogenic drugs in the main pediatric malignant solid tumors and also an overview of clinical trials currently underway. It should be noted that due to the rarity and heterogeneity of the different types of pediatric cancer, most studies on antiangiogenic drugs include only a small number of patients or isolated clinical cases, so they are not conclusive and further studies are needed.

Cutaneous reactions to pediatric cancer treatment part II: Targeted therapy

Cancer remains a leading cause of morbidity and mortality among children. Targeted therapies may improve survivorship; however, unique side-effect profiles have also emerged with these novel therapies. Changes in hair, skin, and nails-termed dermatologic adverse events (AEs)-are among the most common sequelae and may result in interruption or discontinuation of therapy. Though dermatologic AEs have been detailed in adults, these findings are not well described in the pediatric population. We reviewed the literature to characterize dermatologic AEs to anticancer targeted therapies available as of July 2020 and summarized the spectrum of clinical findings as well as treatment recommendations for children. Dermatologic AEs are among the most common AEs reported in pediatric patients receiving targeted therapy, but morphologic and histologic descriptions are often lacking in current publications. Pediatric dermatologists are uniquely poised to recognize specific morphology of dermatologic AEs and make recommendations for prevention and treatment that may improve quality of life and enable ongoing cancer therapy.

Anti-Angiogenic Agents in Management of Sarcoma Patients: Overview of Published Trials

We reviewed all fully published clinical trials assessing anti-angiogenic agents in sarcoma patients (last issue, January 13, 2020). Anti-angiogenic macromolecules (e.g., bevacizumab or ombrabulin) provide disappointing results. Many multikinase inhibitors have been assessed with non-randomized phase II trials with limited samples and without stratification according to histological subtypes, therefore interpretation of such trials is very challenging. On the contrary, pazopanib, regorafenib, and sorafenib have been assessed using double-blind placebo-controlled randomized phase II or phase III trials. Compared to placebo, sorafenib demonstrates activity in desmoid-type fibromatosis patients. Based on results of phase 3 trial, pazopanib had obtained approval for treatment of pretreated non-adipocytic soft tissue sarcoma. Regorafenib is currently assessed in several clinical settings and provides significant improvement of progression-free survival in pre-treated non-adipocytic soft tissue sarcoma and in advanced pretreated osteosarcoma. Multikinase inhibitors are a breakthrough in sarcoma management. Many trials are ongoing. Nevertheless, predictive factors are still missing.

Receptor Tyrosine Kinases in Osteosarcoma Treatment: Which Is the Key Target?

Recent clinical trials have shown several multi-target tyrosine kinase inhibitors (TKIs) to be effective in the treatment of osteosarcoma. However, these TKIs have a number of targets, and it is yet unclear which of these targets has a key role in osteosarcoma treatment. In this review, we first summarize the TKIs that were studied in clinical trials registered on ClinicalTrials.gov. Further, we compare and discuss the targets of these TKIs. We found that TKIs with promising therapeutic effect for osteosarcoma include apatinib, cabozantinib, lenvatinib, regorafenib, and sorafenib. The key targets for osteosarcoma treatment may include VEGFRs and RET. The receptor tyrosine kinases (RTKs) MET, IGF-1R, AXL, PDGFRs, KIT, and FGFRs might be relevant but unimportant targets for osteosarcoma treatment. Inhibition of one type of RTK for the treatment of osteosarcoma is not effective. It is necessary to inhibit several relevant RTKs simultaneously to achieve a breakthrough in osteosarcoma treatment. This review provides comprehensive information on TKI targets relevant in osteosarcoma treatment, and it will be useful for further research in this field.

The Efficacy and Safety of Apatinib in Refractory/Relapse Advanced Pediatric Solid Tumor: A Retrospective Study

Background

The prognosis of recurrent or refractory advanced childhood solid tumor patients is very poor and new therapeutic strategies are in urgent need. This study aimed to determine the efficacy and safety of apatinib in pediatric refractory/relapse advanced solid tumor patients.

Patients and Methods

The study retrospectively reviewed recurrent or refractory advanced pediatric solid tumor patients who were treated with apatinib, an oral small-molecule tyrosine kinase inhibitor (TKI) that targets vascular endothelial growth factor receptor-2 (VEGFR2), at the Sun Yat-sen University Cancer Center (China) from January 2016 to March 2019.

Results

Fifty-six patients were included in the safety evaluation and 49 patients were included in the efficacy evaluation. The objective responses rate (ORR) was 26.5% (95% CI 15–41): 0 CR (complete response) and 13 PR (partial response). Disease control rate (DCR) (CR+PR+SD) was 79.6% (95% CI 65–90). The median progression-free survival (PFS) was 4.0 months (95% CI 2.6–5.4). There was no significant difference for ORR or PFS between the A (apatinib monotherapy), A+MT (apatinib combined with oral metronomic therapy) and A+SC (apatinib combined with salvage combination chemotherapy) group (p>0.05). The most common grade 3 or 4 adverse events were neutropenia (9[16.1%]), thrombocytopenia (8[14.3%]), hand-foot syndrome (3[5.4%]), hypertension (3[5.4%]), anaemia (3[5.4%]) and mucositis (2[3.6%]). Hypertension was the most serious adverse event and one death that occurred was considered as drug-related.

Conclusion

Apatinib showed promising clinical activity in heavily treated recurrent or refractory advanced childhood solid tumor patients. However, it is necessary to pay special attention to monitoring blood pressure when using apatinib in children. Prospective randomized controlled clinical trial is warranted.

The Osteosarcoma Microenvironment: A Complex But Targetable Ecosystem

Osteosarcomas are the most frequent primary bone sarcomas, affecting mainly children, adolescents, and young adults, and with a second peak of incidence in elderly individuals. The current therapeutic management, a combined regimen of poly-chemotherapy and surgery, still remains largely insufficient, as patient survival has not improved in recent decades. Osteosarcomas are very heterogeneous tumors, both at the intra- and inter-tumor level, with no identified driver mutation. Consequently, efforts to improve treatments using targeted therapies have faced this lack of specific osteosarcoma targets. Nevertheless, these tumors are inextricably linked to their local microenvironment, composed of bone, stromal, vascular and immune cells and the osteosarcoma microenvironment is now considered to be essential and supportive for growth and dissemination. This review describes the different actors of the osteosarcoma microenvironment and gives an overview of the past, current, and future strategies of therapy targeting this complex ecosystem, with a focus on the role of extracellular vesicles and on the emergence of multi-kinase inhibitors.

Circular RNA circ_001621 promotes osteosarcoma cells proliferation and migration by sponging miR-578 and regulating VEGF expression

Strategies targeted vascular endothelial growth factor (VEGF)-dependent osteosarcoma progression are limited although important progress has been made in illustrating the mechanisms. Here we identified circ_001621 as one of the significantly upregulated circular RNAs (circRNAs) by circRNAs microarrays. We found that patients with high circ_001621 expression had a shorter survival time. Moreover, we found several potential sponge micro RNAs (miRNA) of circ_001621 with Circular RNA Interactome database. Among the candidate sponge, we elucidated the association of circ_001621 and miR-578. In addition, we demonstrated that miR-578 targeted circ_001621 directly. Functionally, we set up the experimental system to investigate the effects of circ_001621/miR-578/VEGF interaction in vitro and in vivo. Results indicated circ_001621-promoted osteosarcoma proliferation and migration via attenuating the inhibition of cyclin-dependent kinase 4 (CDK4) and matrix metallopeptidase 9 (MMP9) by miR-578, respectively. Nude mice experiment was further performed to estimate the promotion of metastasis by circ_001621. The present study evaluated the mechanisms underlying circ_001621 enhanced osteosarcoma progression and provided novel therapeutic targets for advanced osteosarcoma.

Randomized Phase II Trial of Bevacizumab or Temsirolimus in Combination With Chemotherapy for First Relapse Rhabdomyosarcoma: A Report From the Children's Oncology Group

PURPOSE

The primary aim of this clinical trial was to prioritize bevacizumab or temsirolimus for additional investigation in rhabdomyosarcoma (RMS) when administered in combination with cytotoxic chemotherapy to patients with RMS in first relapse with unfavorable prognosis.

PATIENTS AND METHODS

Patients were randomly assigned to receive bevacizumab on day 1 or temsirolimus on days 1, 8, and 15 of each 21-day treatment cycle, together with vinorelbine on days 1 and 8, and cyclophosphamide on day 1 for a maximum of 12 cycles. Local tumor control with surgery and/or radiation therapy was permitted after 6 weeks of treatment. The primary end point was event-free survival (EFS). Radiographic response was assessed at 6 weeks. The study had a phase II selection that was design to detect a 15% difference between the two regimens (α = .2; 1-β = 0.8; two sided test).

RESULTS

Eighty-seven of 100 planned patients were enrolled when the trial was closed after the second interim analysis after 46 events occurred in 68 patients with sufficient follow-up. The O'Brien Fleming boundary at this analysis corresponded to a two-sided P value of .058 with an observed two-sided P value of .003 favoring temsirolimus. The 6-month EFS for the bevacizumab arm was 54.6% (95% CI, 39.8% to 69.3%) and 69.1% (95% CI, 55.1% to 83%) for the temsirolimus arm. Objective response rates were 28% (95% CI, 13.7% to 41.3%) and 47% (95% CI, 31.5% to 63.2%) for the bevacizumab and temsirolimus arms, respectively (P = .12) and, 28% of patients on bevacizumab and 11% on temsirolimus had progressive disease at 6 weeks.

CONCLUSION

Patients who received temsirolimus had a superior EFS compared with bevacizumab. Temsirolimus has been selected for additional investigation in newly diagnosed patients with intermediate-risk RMS.

Curative-intent radiotherapy for pediatric osteosarcoma: The St. Jude experience

BACKGROUND

Radiation therapy (RT) confers local tumor control and survival advantages in some patients with osteosarcoma, yet pediatric and adolescent and young adult (AYA) population studies are limited.

METHODS

Twenty-eight patients treated with curative-intent RT (median dose, 59.4 Gy; range, 40-76 Gy) at our institution from 1990 to 2017 were retrospectively identified. Cumulative incidence (CIN) of local failure (LF) was estimated by Gray's method and overall survival (OS) by the Kaplan-Meier method. Competing-risk regression and Cox proportional hazards models determined predictors of outcome. Toxicity was reported according to CTCAE v4.0.

RESULTS

With a median follow-up of 99.1 months in living patients, nine patients (32.1%) developed LF. Estimated CINs of LF with competing risk of death at 5 years for the entire cohort, patients at initial diagnosis (n = 16), and recurrent/refractory patients (n = 12) were 32.7% (95% CI, 16.0-50.5%), 25.0% (95% CI, 7.3-48.0%), and 43.8% (95% CI, 13.6-71.0%), respectively (P  =  0.31). Estimated 5-year OS was 42.6% (95% CI, 23.2-62.0%), 54.6% (95% CI, 29.5-79.6%), and 24.3% (95% CI, 0-52.2%), respectively (P  =  0.15). No clinicopathologic features were significantly associated with LF, yet lack of chemotherapy or metastasis at the time of RT was independent significant prognostic factors of decreased OS. Eleven patients experienced RT-related morbidity, with two grade 3 toxicities and no grade 4/5 events.

CONCLUSIONS

Curative-intent RT in pediatric and AYA patients was well tolerated and achieved a local tumor control rate of 75% in patients with primary disease. Local control rates were similar to those in primarily adult studies, with similar or lower doses.

CDC20 and its downstream genes: potential prognosis factors of osteosarcoma

BACKGROUND

We investigated the microarray data GSE42352 to identify genes that can be used as prognosis factors in osteosarcoma.

METHODS

Gene Ontology (GO) biological process analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of Cytoscape ClueGo were used in verifying the function of different genes. Realtime-PCR were used to confirm the microarray results. 83 patient samples were collected and underwent Kaplan-Meier survival analysis and multivariate analysis to predict the prospect of genes using as prognosis factors.

RESULTS

After analyzing the microarray data GSE42352, mitosis metaphase to anaphase-related genes CDC20, securin, cyclin A2 and cyclin B2 were found to be overexpressed in osteosarcoma cell lines. Kaplan-Meier survival analysis showed that overexpression of these genes can predict poor prognosis outcomes in osteosarcoma patients. Furthermore, any combination of the four genes seems to be more effective in predicting osteosarcoma outcomes than any of these genes alone.

CONCLUSIONS

CDC20 and its downstream substracts securin, cyclin A2 and cyclin B2 are good factors that can predict prognosis outcomes in osteosarcoma. Any two combination of these four genes are more effective to be used as osteosarcoma prognosis factors.

Integrated analysis of long-term growth and bone development in pediatric and adolescent patients receiving bevacizumab

BACKGROUND

We conducted an integrated analysis of clinical data to describe long-term effects of bevacizumab on growth and bone development in pediatric and adolescent patients with solid tumors.

PROCEDURE

Clinical data were pooled from five phase I/II trials of bevacizumab versus chemotherapy: BERNIE, HERBY, and AVF4117s enrolled newly diagnosed patients, AVF3842s and AVF2771s enrolled patients with relapsed/refractory disease. Height, weight, body mass index (BMI), and bone-age data were pooled by treatment group. Growth charts were used to track and monitor growth in relation to a reference population of healthy children. Bone age was measured based on X-ray of the left hand and wrist. Analyses were exploratory/descriptive.

RESULTS

Overall, 268 patients received bevacizumab ± chemotherapy and 135 received chemotherapy alone. Baseline characteristics were generally balanced. Median duration of long-term follow-up was 41.8 months (range, 2.4-75.1) with bevacizumab and 22.9 months (range, 2.8-69.2) with chemotherapy alone. Patients had age-appropriate baseline height and weight. Mean height and weight percentiles decreased over time in both treatment groups, but remained within the normal range (height: mean standard deviation score [SDS] range -2 to +3; weight: mean SDS range -2 to +1). Similar trends were seen in BMI. A tendency for reduced growth velocity relative to the reference population was observed at 6 months and 1 year in both groups, but there was no additional decrease for patients receiving bevacizumab.

CONCLUSION

Bevacizumab did not appear to have additional negative effects on growth or development of pediatric and adolescent patients with solid tumors.

The Clonal Evolution of Metastatic Osteosarcoma as Shaped by Cisplatin Treatment

To investigate the genomic evolution of metastatic pediatric osteosarcoma, we performed whole-genome and targeted deep sequencing on 14 osteosarcoma metastases and two primary tumors from four patients (two to eight samples per patient). All four patients harbored ancestral (truncal) somatic variants resulting in TP53 inactivation and cell-cycle aberrations, followed by divergence into relapse-specific lineages exhibiting a cisplatin-induced mutation signature. In three of the four patients, the cisplatin signature accounted for >40% of mutations detected in the metastatic samples. Mutations potentially acquired during cisplatin treatment included NF1 missense mutations of uncertain significance in two patients and a KIT G565R activating mutation in one patient. Three of four patients demonstrated widespread ploidy differences between samples from the sample patient. Single-cell seeding of metastasis was detected in most metastatic samples. Cross-seeding between metastatic sites was observed in one patient, whereas in another patient a minor clone from the primary tumor seeded both metastases analyzed. These results reveal extensive clonal heterogeneity in metastatic osteosarcoma, much of which is likely cisplatin-induced. IMPLICATIONS: The extent and consequences of chemotherapy-induced damage in pediatric cancers is unknown. We found that cisplatin treatment can potentially double the mutational burden in osteosarcoma, which has implications for optimizing therapy for recurrent, chemotherapy-resistant disease.

Multi-level otsu method to define metabolic tumor volume in positron emission tomography

This study was to validate reliability and clinical utility of a PET tumor segmentation method using multi-level Otsu (MO-PET) in standard National Electrical Manufacturers Association (NEMA) image quality (IQ) phantom and patients with osteosarcoma. The NEMA IQ phantom was prepared with a lesion-to-background ratio (LBR) of either 8:1, 4:1, or 1.5:1. The artificial lesions in the phantom were segmented using MO-PET, gradient-based method (PETedge), relative threshold methods, and background threshold methods. Metabolic tumor volumes (MTVs) using MO-PET and PETedge were named as MTV (MO-PET) and MTV (PETedge), respectively. Among the MTVs using multiple methods, only MTV (MO-PET) and MTV (PETedge) showed excellent agreements with the actual volume of NEMA IQ phantom across the different LBRs (intraclass correlation coefficient, ICC = 0.987, 0.985 in LBR 8:1, 0.981, 0.993 in LBR 4:1 and 0.947, 0.994 in LBR 1.5:1). Repeated measurements of MTV (MO-PET) of the primary tumors showed excellent reproducibility with ICC of 0.994 (0.989-0.997) in patients with osteosarcoma. Also, MTV (MO-PET) was found to be predictive of Event Free Survival (EFS) [Hazard ratio (95% CI) = 6.1 (2.1-17.2), log rank P = 0.0003] in patients with osteosarcoma. We have validated in NEMA IQ phantom that the MTV (MO-PET) is accurate, and importantly, stable and consistent across a range of lesion sizes and LBRs representative of clinical tumor lesions. Furthermore, MTV (MO-PET) showed excellent reproducibility and was predictive for EFS in patients with osteosarcoma.

LINC01116 targets miR-520a-3p and affects IL6R to promote the proliferation and migration of osteosarcoma cells through the Jak-stat signaling pathway

OBJECTIVE

The purpose of this study was to find out the important lncRNA-miRNA-mRNA axis and pathway in osteosarcoma (OS) through bioinformatics analysis and verify the biological functions of lncRNA/miRNA/mRNA in OS through in vitro and in vivo assays.

METHODS

The differential expression mRNAs and lncRNAs were identified through microarray analysis, and the altered pathways were identified by GSEA. The Pearson Coefficient was used to analyze the correlations between mRNAs and lncRNAs. Kaplan-Meier survival analysis was preformed using patient information in GEO database. Their target miRNAs were predicted by Targetscan and miRanda database and confirmed by dual luciferase reporter assay. QRT-PCR were utilized to detected the relative expressions of mRNAs, miRNAs and lncRNAs. The expressions of IL6R protein and pathway related proteins were detected by western blot. OS cell viability, migration and apoptosis were determined through MTT assay, Transwell assay and flow cytometry. Tumor formation in nude mice verified the influence of LINC01116 in vivo.

RESULTS

The Jak-stat signaling pathway was activated in OS tissues. LINC01116 expression was positively correlated with IL6R expression. MiR-520a-3p targeted the 3'-UTR of LINC01116 and IL6R. Lower expression levels of miR-520a-3p significantly correlated with shorter survival of patients. LINC01116 and IL6R were up-regulated while miR-520a-3p was down-regulated in OS. LINC01116 and IL6R promoted the viability and migration of OS cells, while miR-520a-3p acted as a tumor suppressor. MiR-520a-3p inhibitor could rescue the suppressive effects of si-LINC011116 and si-IL6R on OS development. The Jak-stat signaling pathway related proteins were also down-regulated by miR-520a-3p. Down-regulation of LINC01116 inhibited the tumor growth in nude mice.

CONCLUSION

LINC01116 up-regulated IL6R in OS through targeting miR-520a-3p, thus activating the Jak-stat signaling pathway and promoting the progression of OS.

Current Molecular Targeted Therapies for Bone and Soft Tissue Sarcomas

Systemic treatment options for bone and soft tissue sarcomas remained unchanged until the 2000s. These cancers presented challenges in new drug development partly because of their rarity and heterogeneity. Many new molecular targeting drugs have been tried in the 2010s, and some were approved for bone and soft tissue sarcoma. As one of the first molecular targeted drugs approved for solid malignant tumors, imatinib's approval as a treatment for gastrointestinal stromal tumors (GISTs) has been a great achievement. Following imatinib, other tyrosine kinase inhibitors (TKIs) have been approved for GISTs such as sunitinib and regorafenib, and pazopanib was approved for non-GIST soft tissue sarcomas. Olaratumab, the monoclonal antibody that targets platelet-derived growth factor receptor (PDGFR)-α, was shown to extend the overall survival of soft tissue sarcoma patients and was approved in 2016 in the U.S. as a breakthrough therapy. For bone tumors, new drugs are limited to denosumab, a receptor activator of nuclear factor κB ligand (RANKL) inhibitor, for treating giant cell tumors of bone. In this review, we explain and summarize the current molecular targeting therapies approved and in development for bone and soft tissue sarcomas.

Anticancer effects of 10-hydroxycamptothecin induce apoptosis of human osteosarcoma through activating caspase-3, p53 and cytochrome c pathways

In order to evaluate the anticancer effect of 10-hydroxycamptothecin (HCPT) in terms of inducing the apoptosis of human osteosarcoma cells, its apoptosis-inducing molecular mechanisms were investigated. In the present study, the anticancer effects of HCPT were revealed to result in suppressed cell viability, increased cytotoxicity, the induction of apoptosis and an augmented apoptotic nucleolus of human osteosarcoma cells. MG-63 cells were cultured with HCPT (0, 20, 40 and 80 nM) for 24 and 48 h. An MTT assay and a lactate dehydrogenase assay were used to analyze the anticancer effect of HCPT on cell viability and cytotoxicity in MG-63 cells. MG-63 cell apoptosis, and caspase-9 and caspase-3 activity levels were evaluated using flow cytometry and an ELISA. Western blot analysis was used to detect the protein expression levels of p53, poly (ADP-ribose) polymerase-1 (PARP-1), cytochrome c and B cell lymphoma-2 (Bcl-2) in MG-63 cells. The anticancer effects of HCPT were demonstrated to significantly activate the protein expression of p53, PARP-1 and cytochrome c, and suppress Bcl-2 protein expression and promote the activity of caspase-9 and caspase-3 in human osteosarcoma cells. In conclusion, the anticancer effects of HCPT appear to induce the apoptosis of human osteosarcoma cells through the activation of the caspase-3, p53 and cytochrome c pathways.