Sarcoma treatment in the era of molecular medicine

Beyond the benign: A rare case report of myxoid pleomorphic liposarcoma

Myxoid pleomorphic liposarcoma is a rare and aggressive subtype of soft tissue sarcomas (STS). It primarily arises from adipose tissue and exhibits a high rate of recurrence and metastatic potential. We report the case of a 35-year-old male gym trainer with a 5-month history of a painless, progressively enlarging mass on the right posterior aspect of chest, diagnosed with myxoid pleomorphic liposarcoma following imaging and histopathological evaluation of the excised specimen. Surgical excision with clear margins and adjuvant radiotherapy resulted in a favorable outcome with no recurrence at 7 months. This case emphasizes the importance of early diagnosis and multidisciplinary approach in managing a rare soft tissue sarcoma to prevent complications from a delayed intervention.

[Practical Guidance on the Detection of NTRK Fusions in Sarcomas: Current Status and Diagnostic Challenges]

Sarcomas are a rare and heterogeneous group of mesenchymal malignant tumors and account for approximately 1% of all adult cancers and around 20% of all pediatric solid tumors in Europe. Technology advances have enabled a more accurate and efficient characterization of the molecular mechanisms underlying the pathogenesis of sarcoma subtypes and revealed novel and unexpected therapeutic targets with prognostic/predictive biomarkers, namely the neurotrophic tyrosine receptor kinase (NTRK) gene fusion. The NTRK fusion assessment has recently become a standard part of management for patients with unresectable locally advanced or metastatic cancers and has been identified in various tumor types. In the more prevalent adult and pediatric sarcomas, NTRK fusions are present in 1% and 20%, respectively, and in more than 90% of very rare subsets of tumors. The inhibition of TRK activity with first-generation TRK inhibitors has been found to be effective and well tolerated in adult and pediatric patients, independently of the tumor type. Overall, the therapeutic benefit to those patients compensates for the difficulties of identifying NTRK gene fusions. However, the rarity and diagnostic complexity of NTRK gene fusions raise several questions and challenges for clinicians. To address these issues, an expert panel of medical and pediatric oncologists, radiologists, surgeons, orthopedists, and pathologists reviewed the recent literature and discussed the current status and challenges, proposing a diagnostic algorithm for identifying NTRK fusion sarcomas. The aim of this article is to review the updated information on this issue and to provide the experts' recommendations and practical guidance on the optimal management of patients with soft tissue sarcomas, infantile fibrosarcoma, gastrointestinal stromal tumors, and osteosarcoma.

Hyperthermia combined with opioid therapy: Enhancing cancer pain management and reducing surgical stress in gastrointestinal cancer patients

In this article, we evaluate the findings of the study by Qian et al, which explores the efficacy of combining hyperthermia with opioid therapy for enhanced cancer pain management in patients with middle and late-stage gastrointestinal tumors. The study undertakes a retrospective analysis comparing traditional opioid therapy to an integrated approach of hyperthermia and opioids across 70 patients, highlighting significant benefits in pain control, reduction of opioid dosage, and minimization of adverse reactions. In our article, we not only discuss these findings but also emphasize the broader implications for clinical practice, particularly in enhancing patient outcomes through innovative pain management strategies. We advocate for further research to establish more robust data supporting this approach and to explore the mechanistic insights that enable these benefits. This discussion reflects on the potential paradigm shift in managing debilitating cancer-related pain, urging a reevaluation of current practices to incorporate these findings effectively.

Functional combinatorial precision medicine for predicting and optimizing soft tissue sarcoma treatments

Soft tissue sarcomas (STS) are rare, heterogeneous tumors with poor survival outcomes, primarily due to reliance on cytotoxic chemotherapy and lack of targeted therapies. Given the uniquely individualized nature of STS, we hypothesized that the ex vivo drug sensitivity platform, quadratic phenotypic optimization platform (QPOP), can predict treatment response and enhance combination therapy design for STS. Using QPOP, we screened 45 primary STS patient samples, and showed improved or concordant patient outcomes that are attributable to QPOP predictions. From a panel of approved and investigational agents, QPOP identified AZD5153 (BET inhibitor) and pazopanib (multi-kinase blocker) as the most effective combination with superior efficacy compared to standard regimens. Validation in a panel of established patient lines and in vivo models supported its synergistic interaction, accompanied by repressed oncogenic MYC and related pathways. These findings provide preliminary clinical evidence for QPOP to predict STS treatment outcomes and guide the development of novel therapeutic strategies for STS patients.

Germline Genetic Testing in Patients with Bone and Soft Tissue Sarcoma: A Prospective Multicenter Study to Evaluate Cancer Susceptibility

Sarcomas are rare heterogenous mesenchymal tumors with over seventy-five different subtypes, with varying biology and outcomes, with no clear inciting factor in the vast majority. To determine the prevalence of pathogenic germline variants (PGV) in patients with sarcomas, we undertook a prospective multi-site study of germline sequencing using an 84-gene next-generation sequencing panel among patients receiving care at the four Mayo Clinic Cancer Centers. Of 115 patients with bone and soft tissue sarcoma, the median age was 60 years, 49.6% were female, 82.6% were White. The anatomical location of the primary tumor included extremities (34.8%), retroperitoneum (19.1%), trunk (13.0%), and head and neck (7.8%). Family history of cancer was present in 62.6% of the study population. Ten patients (8.7%) had a pathogenic/likely pathogenic variant (PGV). Of these, three had stage IV sarcoma, and seven had earlier-stage sarcoma (stages I-III). Among the 55 (48.7%) patients who had variant of uncertain significance (VUS), 41.1% (22/55) had stage IV sarcoma and 58.9% (33/55) had earlier-stage disease. Of the ten patients with PGV, high-to-moderate penetrance gene abnormalities were identified in eight patients (80%) involving TP53 (3), BRCA1 (1), SDHA (1), ATM (2), and NBN (1) genes. The vast majority of the PGVs (70%) would not have been detected using the current guidelines. Because of the paucity of sarcomas and lack of effective treatment options for advanced disease, germline testing in sarcomas represents a potentially impactful strategy to assess therapeutic options and for assessment of familial risk.

A new promising anticancer agent: A glycosaminoglycan-mimetic derived from the marine bacterial infernan exopolysaccharide

Marine microorganisms are a promising source of innovative compounds for medical applications. The present study aimed to investigate anticancer potential of oversulfated low molecular weight derivatives, named OSIDs, prepared from infernan, a marine bacterial exopolysaccharide. In order to identify a lead, OSIDs with different sulfate contents and molecular weights were firstly evaluated in vitro in a large series of human and murine tumor cell lines. Among all derivatives tested, OSID4 was the most effective, showing a significant dose-dependent inhibitory effect on the viability of cancer cells. OSID4 was then able to significantly slow down progression of lung and melanoma tumor growth in immunocompetent tumor-bearing mouse models. In immunodeficient mice bearing a human lung carcinoma, a notable inhibitory effect of OSID4, comparable to doxorubicin, was observed. In combination with doxorubicin, OSID4 did not exhibit any drug interaction. The activity of OSID4 was confirmed by its modulatory effect on the transcriptomic profile of human lung cancer cells. Finally, toxicity and pharmacokinetic parameters disclosed that OSID4 presented no toxicity and no bleeding risk. In conclusion, by combining its notable anticancer and moderate anticoagulant activities, OSID4 may be promising for treatment of cancers associated with a high risk of thromboembolic events.

Enhancing precision in sarcoma diagnosis: nCounter fusion panel implementation in a middle-income country

Background

Sarcoma diagnosis is challenging due to numerous subtypes with similar histopathological features and the high cost of fusion detection methods, particularly in middle-income countries.

Objectives

To implement a cost-effective custom-based nCounter approach previously validated for fusion analysis of suspected sarcoma in Brazil.

Design and methods

RNA isolated from 56 routine sarcomas, which were formalin-fixed and paraffin-embedded, was analyzed using a custom nCounter assay that detects 174 common sarcoma gene fusions. The results were compared to fluorescence in situ hybridization (FISH)/next-generation sequencing (NGS) and clinicopathological data.

Results

The nCounter assay was conclusive in 98.2% of cases, identifying 25 gene fusions with 82.5% accuracy, 76.6% sensitivity, and 100% specificity compared to FISH/NGS.

Conclusion

Although it does not identify all sarcoma fusions, especially for rare subtypes, the present nCounter assay is a rapid, affordable, and accurate tool for sarcoma diagnosis in resource-limited settings.

Exploring CX3CR1 as a prognostic biomarker and immunotherapeutic target in sarcoma

BACKGROUND

Sarcomas (SARC) are a diverse group of malignant tumors originating from mesenchymal tissues, characterized by poor prognosis under conventional therapies. CX3CR1, a chemokine receptor involved in immune cell migration, has emerged as a key player in SARC. Post-translational modifications (PTMs) such as phosphorylation and ubiquitination critically modulate CX3CR1, influencing cancer progression, immune responses, and treatment resistance.

METHODS

This study investigates CX3CR1 expression, its biological functions, and prognostic value in SARC. Using data from The Cancer Genome Atlas (TCGA), we analyzed CX3CR1 gene expression, methylation patterns, CRISPR screening results, and immune infiltration metrics. Functional experiments included knockout and overexpression models, CCK-8 assays and flow cytometry to assess apoptosis.

RESULTS

CX3CR1 expression was significantly elevated in SARC tissues and positively correlated with overall survival, disease-specific survival, and progression-free intervals. Methylation analysis identified CpG sites associated with CX3CR1 expression, differentiating tumor and adjacent tissues. CRISPR screening highlighted CX3CR1's essential role in tumor growth, while immune infiltration analysis underscored its impact on the tumor microenvironment. PTMs were found to stabilize CX3CR1, enhancing its activity in key signaling pathways. Overexpression of CX3CR1 amplified inflammatory and apoptotic responses, while knockdown showed protective effects in vitro.

CONCLUSIONS

CX3CR1 serves as a promising prognostic biomarker and therapeutic target in sarcoma. Targeting CX3CR1's PTMs could advance personalized treatments and improve outcomes for sarcoma patients.

A promising role of noble metal NPs@MOFs in chondrosarcoma management

Chondrosarcoma, a challenging and malignant neoplasm originating from cartilage cells, poses significant diagnostic and therapeutic hurdles due to its resistance to conventional treatments and the complexity of its diagnosis. Noble metal nanoparticle-embedded metal-organic frameworks (NPs@MOFs) stand out as a novel approach for the diagnosis and treatment of chondrosarcoma. This review delves into the properties and applications of NPs@MOFs, focusing on their classification by noble metal type and their role in enhancing photothermal therapy (PTT), photodynamic therapy (PDT), targeted drug delivery and chondrosarcoma diagnosis. Despite promising in vitro and in vivo results, challenges such as understanding the mechanisms of action and clinical translation remain, and the therapeutic effect of PTT and PDT on deep chondrosarcoma seems unsatisfactory. Future exploration, such as combined therapy and multiple MOF therapy, could unlock the full potential of noble metal NPs@MOFs in revolutionizing chondrosarcoma management, offering insights into the prospect of these materials in chondrosarcoma management.

Osteosarcoma and Ewing Sarcoma of Bone: An Italian Mono-Institutional Epidemiological Study

Background/Objectives: Musculoskeletal neoplasms are rare and challenging diseases. Their geographic pattern varies worldwide, and no studies analyze their distribution in Italy. The aim of this study was to investigate a possible association between clinical variables to a period of diagnosis and geographic origin in Italy. Moreover, we wanted to describe the survival rate of bone osteosarcoma (OS) and Ewing sarcoma (EwS) from the Rizzoli Orthopaedic Institute (IOR) experience. Methods: We retrospectively reviewed 3098 diagnoses of high-grade bone OS and EwS made at the IOR in the past 40 years (1982-2021). Incidence, measures of associations, and survival rates have been analyzed. Results: The time of diagnosis and geographic origin were associated either with each other or with age and stage of tumor. Overall, the 10-year survival rate was 54% (95% CI 52-56) and 53% (95% CI 50-56) for bone OS and EwS, respectively. Multivariate analyses showed that adverse factors at diagnosis are age, location, stage, and time of diagnosis, in both cohorts. Conclusions: We confirmed known prognostic factors, and owing to the large cohort, we highlight their importance in clinical practice. No differences were observed in patient survival associated with different areas of Italy, although geographic origin was associated with most clinical variables analyzed, suggesting a further factor to investigate. Given the above-mentioned results, a Sarcoma Specialist Network with a recognized expertise is determinably in charge of the management of sarcomas.

(B)On(e)-cohistones and the epigenetic alterations at the root of bone cancer

Identification of mutations in histones in a number of human neoplasms and developmental syndromes represents the most compelling evidence to date for a causal role of epigenetic perturbations in human disease. In most cases, these mutations have gain of function properties that cause deviation from normal developmental processes leading to embryo defects and/or neoplastic transformation. These exciting discoveries represent a step-change in our understanding of the role of chromatin (dys)regulation in development and disease. However, the mechanisms of action of oncogenic histone mutations (oncohistones) remain only partially understood. Here, we critically assess existing literature on oncohistones focussing mainly on bone neoplasms. We show how it is possible to draw parallels with some of the cell-autonomous mechanisms of action described in paediatric brain cancer, although the functions of oncohistones in bone tumours remain under-investigated. In this respect, it is becoming clear that histone mutations targeting the same residues display, at least in part, tissue-specific oncogenic mechanisms. Furthermore, it is emerging that cancer cells carrying oncohistones can modify the surrounding microenvironment to support growth and/or alter differentiation trajectories. A better understanding of oncohistone function in different neoplasms provide potential for identification of signalling that could be targeted therapeutically. Finally, we discuss some of the main concepts and future directions in this research area, while also drawing possible connections and parallels with other cancer epigenetic mechanisms.

Patient-derived tumor organoids: A preclinical platform for personalized cancer therapy

Patient-derived tumor organoids (PDTOs) represent a significant advancement in cancer research and personalized medicine. These organoids, derived from various cancer types, have shown the ability to retain the genetic and molecular characteristics of the original tumors, allowing for the detailed study of tumor biology and drug responses on an individual basis. The success rates of establishing PDTOs vary widely and are influenced by factors such as cancer type, tissue quality, and media composition. Furthermore, the dynamic nature of organoid cultures may also lead to unique molecular characteristics that deviate from the original tumors, affecting their interpretation in clinical settings without the implementation of rigorous validation and establishment of standardized protocols. Recent studies have supported the correlation between PDTOs and the corresponding patient response. Although these studies involved a small number of patients, they promoted the integration of PDTOs in observational and interventional clinical trials to advance translational cancer therapies.

CIRCUS: CIRCUlating tumour cells in soft tissue Sarcoma - a short report

Aims: Circulating tumour cells (CTCs) can be detected in peripheral blood using their physical properties (increased size and less deformable than normal circulating blood cells) or using cell surface markers. The study of these CTCs should provide important insights into tumour biology, including mechanisms of drug resistance. We performed a pilot study (IRAS ID: 235459) to evaluate if CTCs could be isolated from peripheral blood samples collected from soft tissue sarcoma (STS) patients. Methods: We used a combined approach that first enriched samples for CTCs using a microfluidic cassette via ParosrtixTMPR1, and then sorted cells stained for vimentin and cytokeratin using the DEPArrayTM. The total circulating cell-free DNA (cfDNA) level was also analysed. Data were correlated with clinical parameters. Results: 13 patients were recruited to this study: 7 patients with localised disease and 6 patients with metastatic disease. CTCs exhibited a high heterogeneity based on their expression of mesenchymal and epithelial markers. There was no significant difference in the number of CTCs between patients with localised versus metastatic disease. We observed no correlation between CTC numbers and cfDNA; however, the number of CTCs did correlate with primary tumour size. Conclusion: The present study demonstrates the presence of CTCs in STS patients with localised and advanced disease. Further and larger studies are needed to characterise STS CTCs and to evaluate their prognostic significance.

Bayesian unsupervised clustering identifies clinically relevant osteosarcoma subtypes

Identification of cancer subtypes is a critical step for developing precision medicine. Most cancer subtyping is based on the analysis of RNA sequencing (RNA-seq) data from patient cohorts using unsupervised machine learning methods such as hierarchical cluster analysis, but these computational approaches disregard the heterogeneous composition of individual cancer samples. Here, we used a more sophisticated unsupervised Bayesian model termed latent process decomposition (LPD), which handles individual cancer sample heterogeneity and deconvolutes the structure of transcriptome data to provide clinically relevant information. The work was performed on the pediatric tumor osteosarcoma, which is a prototypical model for a rare and heterogeneous cancer. The LPD model detected three osteosarcoma subtypes. The subtype with the poorest prognosis was validated using independent patient datasets. This new stratification framework will be important for more accurate diagnostic labeling, expediting precision medicine, and improving clinical trial success. Our results emphasize the importance of using more sophisticated machine learning approaches (and for teaching deep learning and artificial intelligence) for RNA-seq data analysis, which may assist drug targeting and clinical management.

Classification of pediatric soft and bone sarcomas using DNA methylation-based profiling

Pediatric sarcomas present heterogeneous morphology, genetics and clinical behavior posing a challenge for an accurate diagnosis. DNA methylation is an epigenetic modification that coordinates chromatin structure and regulates gene expression, determining cell type and function. DNA methylation-based tumor profiling classifier for sarcomas (known as sarcoma classifier) from the German Cancer Research Center (Deutsches Krebsforschungszentrum) was applied to 122 pediatric sarcomas referred to a reference pediatric oncology hospital. The classifiers reported 88.5% of agreement between histopathological and molecular classification confirming the initial diagnosis of all osteosarcomas and Ewing sarcomas. The Ewing-like sarcomas were reclassified into sarcomas with BCOR or CIC alterations, later confirmed by orthogonal diagnostic techniques. Regarding the CNAs profile, osteosarcomas had several chromosomal gains and losses as well as chromothripsis, whereas Ewing sarcomas had few large events, such as amplifications of chromosomes 8 and 12. The molecular classification together with clinical and histopathological assessment could improve the diagnosis of pediatric sarcomas although there are limitations to deal with more rare classes. This study provides an increase in the number of sarcomas evaluated for DNA methylation profiling in the pediatric population.

The causal relationship between gut microbiota and 2 neoplasms, malignant and benign neoplasms of bone and articular cartilage: A two-sample Mendelian randomization study

Previous research has demonstrated a close connection between the development of bone neoplasms and variations in the abundance of specific gut microbiota. It remains unclear, however, how the gut microbiota and bone neoplasms are causally related. Hence, in our study, we aim to clarify this relationship between gut microbiota and 2 neoplasms, malignant neoplasm of bone and articular cartilage (MNBAC) and benign neoplasm of bone and articular cartilage (BNBAC), by employing a two-sample Mendelian randomization (MR) approach. In this study, single nucleotide polymorphisms (SNPs) from genome-wide association studies-pooled data related to bone neoplasms and gut microbiota abundance were evaluated. The inverse variance weighted was employed as the major method for assessing the aforementioned causal relationship. Furthermore, the horizontal multiplicity was evaluated utilizing the Mendelian randomization pleiotropy residual sum and outlier and the MR-Egger intercept test. Finally, inverse MR analysis was performed to assess reverse causality. Inverse variance weighted results indicate a potential genetic relationship between 4 gut microbiota and MNBAC, and 3 gut microbiota and BNBAC. On the one hand, Eubacterium eligens group (OR = 0.16, 95% CI = 0.04-0.67, P = .01), Odoribacter (OR = 0.23, 95% CI = 0.06-0.84, P = .03), Slackia (OR = 0.35, 95% CI = 0.13-0.93, P = .04), and Tyzzerella3 (OR = 0.44, 95% CI = 0.24-0.82, P = .01) exhibited a protective effect against MNBAC. On the other hand, of the 3 gut microbes identified as potentially causally related to BNBAC, Oscillibacter (OR = 0.79, 95% CI = 0.63-0.98, P = .03) and Ruminococcus torques group (OR = 0.62, 95% CI = 0.39-0.98, P = .04) were regarded as protective strains of B, while Eubacterium ruminantium group (OR = 1.24, 95% CI = 1.04-1.47, P = .02) was considered to be a risk factor for increasing the incidence of BNBAC. Additionally, the bone neoplasms were not found to have a reverse causal relationship with the above 7 gut microbiota taxa. Four gut microbiota showed causal effects on MNBAC, and 3 gut microbiota demonstrated causality in BNBAC, providing insights into the design of future interventions to reduce the burden of neoplasms.

Significance of exosomes in osteosarcoma research: a systematic review and meta-analysis of a singular clinical investigation

Background

Osteosarcoma is the most prevalent among primary bone malignancies, and its standard intervention involves neoadjuvant chemotherapy - surgical adjuvant chemotherapy (MAP regimen) with adriamycin, cisplatin, and high-dose methotrexate. Early-stage osteosarcoma can be effectively treated with surgical resection along with chemotherapy or radiotherapy. However, as the cancer progresses, the efficacy of chemo- and radiotherapy decreases, and the associated problems increase. The current understanding of osteosarcoma development, diagnosis, and treatment does not meet clinical demands. More recently, there has been a significant increase in exosome-associated osteosarcoma research, potentially opening up novel possibilities for osteosarcoma research.

Purpose

We comprehensively evaluated and analyzed the advancement of preclinical research related to exosome-osteosarcoma. We aimed to establish a practical, theoretical foundation for future research initiatives.

Study design

The selected design was a systematic review and meta-analysis.

Methods

Scientific databases, such as PubMed, Embase, The Cochrane Library, and Web of Science, were extensively screened for exosome and osteosarcoma articles. Two highly trained investigators separately reviewed the literature, extracted relevant information, and assessed study quality. Subsequently, we conducted a meta-analysis using Review Manager 5.4.

Results

In total, 25 animal-based randomized controlled trials (RCTs) were selected for analysis. Among them, 13 studies provided strong evidence of cellular exosomes regulating osteosarcoma development from bone marrow mesenchymal stem cells, osteosarcoma cells, and macrophages. In addition, 12 studies demonstrated the therapeutic potential of exosomes in managing osteosarcoma, among which 7 studies transplanted transfected exosomes directly into animals as drugs, and five studies employed exosomes as drug carriers, which were next transplanted into animals.

Conclusion

Based on our meta-analysis, macrophages strongly modulate osteosarcoma development, and engineered exosomes provide the most effective exosome-based osteosarcoma treatment.

Single-Cell Spatial-Temporal Analysis of ZNF451 in Mediating Drug Resistance and CD8+ T Cell Dysfunction

Cisplatin is widely used to treat osteosarcoma, but recurrent cases often develop resistance, allowing the disease to progress and complicating clinical management. This study aimed to elucidate the immune microenvironment of osteosarcoma, providing insights into the mechanisms of recurrence and identifying potential therapeutic strategies. By analyzing multiple single-cell and bulk RNA-sequencing datasets, we discovered that the SUMOylation-related gene ZNF451 promotes osteosarcoma recurrence and alters its immune microenvironment. ZNF451 was found to importantly enhance the growth, migration, and invasion of resistant cells while also reducing their sensitivity to cisplatin and lowering their apoptosis rate. Moreover, our data indicated that ZNF451 plays a crucial role in bone resorption and epithelial-mesenchymal transition. ZNF451 also regulates CD8+ T cell function, leading to their exhaustion and transition to the CD8T.EXH state. Additionally, β-cryptoxanthin has been identified as a potential therapeutic agent that inhibits osteosarcoma progression by targeting ZNF451. In summary, these findings highlight the critical role of ZNF451 in promoting osteosarcoma progression and underscore its potential as a therapeutic target and biomarker for osteosarcoma.

Theranostic strategies in sarcoma: preliminary clinical evidence

INTRODUCTION

Sarcomas encompass a highly diverse range of malignancies, characterized by varied morphological and molecular profiles. Treatment options in case of therapy-refractory or advanced disease are limited. In this context, theranostics emerges as an innovative platform seamlessly integrating diagnosis and therapy, offering promising prospects.

AREAS COVERED

This special report delves into the initial clinical applications of theranostic-based approaches in sarcomas. Specifically, it examines various strategies targeting biomarkers associated with sarcomas, including fibroblast activation protein (FAP), prostate-specific membrane antigen (PSMA), C-X-C chemokine receptor type 4 (CXCR4) and somatostatin receptor 2 (SSTR2).

EXPERT OPINION

The heterogeneous uptake of the CXCR4-targeted radioligand in lesions, along with its poor correlation with immunohistochemistry data, diminishes the attractiveness of this theranostic approach in the sarcoma oncological setting. SSTR2-targeted approaches in sarcoma, although potentially effective, are limited to a single case. Early experiences with FAP inhibitors in sarcoma patients have shown particularly promising outcomes, indicating effective disease control with minimal toxicity. While PSMA presents an enticing target for theranostic approaches in sarcomas, its utilization remains anecdotal and requires further investigation. Prospective and well-designed clinical trials are imperative to delineate the potential impact of FAPI- and PSMA-based approaches on sarcoma therapeutic landscapes, offering innovative and personalized treatment options.

Neoadjuvant Chemotherapy for Adults with Osteogenic Sarcoma

OPINION STATEMENT

Osteosarcoma is the most common primary malignant bone tumor in adolescents and adults. The 5-year survival rate is 65% when localized; however, survival drops dramatically to 10-20% in cases of metastatic disease. Therapy for osteosarcoma saw its first significant advancement in the 1970-80's, with the introduction of our current standard of care, consisting of the neo/adjuvant treatment regimen methotrexate, doxorubicin (Adriamycin), and cisplatin (collectively referred to as MAP) and surgical resection. Since MAP, development of a better therapeutic approach has stalled, creating a plateau in patient outcomes that has persisted for 40 years. Despite substantial research into a variety of pathways for novel treatment options, clinical trials have not produced sizeable improvements in outcomes. In this article, we discuss our current neoadjuvant standard of care therapy, followed by a review of contemporary therapeutic options, including tyrosine kinase inhibitors (TKIs), immune checkpoint inhibitors (ICIs), monoclonal antibodies (mAbs), and chimeric antigen receptor (CAR) T cells. Lastly, we consider the challenges hindering the success of novel treatment options and future research directions.

Roles and Applications of Circulating Tumor-Derived RNAs in Sarcoma Patients: A Systematic Review

Sarcomas are a heterogeneous group of malignancies with a high mortality rate. Detection of circulating tumor-derived material, such as circulating RNA in the peripheral blood of patients, has shown to be useful in diagnosis, prediction of prognosis and disease monitoring in several malignancies. This systematic review aims to probe the existing methods for detecting circulating tumor-derived RNAs from patients affected by sarcoma and their possible clinical application. A systematic review of the literature indexed in PubMed was performed. Each article had to analyze circulating RNA in human specimens obtained from liquid biopsies of patients affected by sarcoma. A total of 26 articles were included. We evaluated 1381 patients; 72% were affected by bone sarcoma and 28% by soft tissue sarcoma. By PCR-based methods, all the studies investigated circulating tumor RNA, mostly in the peripheral blood. Nearly half of the authors investigated the tumor expression and/or release of miRNA (42%). Several authors pointed out that circulating tumor-derived RNA has proven to have potential application in a clinical setting for sarcomas. To the best of our knowledge, this is the first review in the literature to attempt to put together data specifically on ctRNA in patients affected by sarcoma.

Evaluating Circulating Biomarkers for Diagnosis, Prognosis, and Tumor Monitoring in Pediatric Sarcomas: Recent Advances and Future Directions

Pediatric sarcomas present a significant challenge in oncology. There is an urgent need for improved therapeutic strategies for high-risk patients and better management of long-term side effects for those who survive the disease. Liquid biopsy is emerging as a promising tool to optimize treatment in these patients by offering non-invasive, repeatable assessments of disease status. Circulating biomarkers can provide valuable insights into tumor genetics and treatment response, potentially facilitating early diagnosis and dynamic disease monitoring. This review examines the potential of liquid biopsies, focusing on circulating biomarkers in the most common pediatric sarcomas, i.e., osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma. We also highlight the current research efforts and the necessary advancements required before these technologies can be widely adopted in clinical practice.

Theoretical Model for In Vivo Induction of Chemotherapy Sensitization Using miRNA Packaged in Distinct Layered Liposomes

Resistance to chemotherapy is a problem of major social and economic importance, when looking at factors like the decrease in life expectancy, the associated therapeutic costs, and a significant number of cancers that resist current chemotherapy. The development of chemotherapeutics for all theoretically possible tumor variants is an approach that requires unreasonable resources. We propose a theoretical model that serves the purpose of overcoming resistance to chemotherapeutic agents used in cancer therapy. The model describes a gene delivery system based on liposomes, which are optically guided to the tumor's location. The main aim of the gene delivery system is inhibiting the activity of enzymes involved in drug metabolism, hence offering the opportunity to use inexpensive chemotherapeutics that are already on the market. This model will reduce the costs of chemotherapy and will assure a positive outcome for patients.

The landscape of drug sensitivity and resistance in sarcoma

Sarcomas are rare malignancies with over 100 distinct histological subtypes. Their rarity and heterogeneity pose significant challenges to identifying effective therapies, and approved regimens show varied responses. Novel, personalized approaches to therapy are needed to improve patient outcomes. Patient-derived tumor organoids (PDTOs) model tumor behavior across an array of malignancies. We leverage PDTOs to characterize the landscape of drug resistance and sensitivity in sarcoma, collecting 194 specimens from 126 patients spanning 24 distinct sarcoma subtypes. Our high-throughput organoid screening pipeline tested single agents and combinations, with results available within a week from surgery. Drug sensitivity correlated with clinical features such as tumor subtype, treatment history, and disease trajectory. PDTO screening can facilitate optimal drug selection and mirror patient outcomes in sarcoma. We could identify at least one FDA-approved or NCCN-recommended effective regimen for 59% of the specimens, demonstrating the potential of our pipeline to provide actionable treatment information.

Let's get functional: Drug sensitivity profiling to enable precision sarcoma medicine

Drug sensitivity profiling in patient-derived tumor models offers new hope for improving outcomes in cancers lacking effective therapies. Al Shihabi et al.1 demonstrate that short-term cultures from bone and soft tissue sarcomas enable clinically meaningful screening of multiple drugs and combinations, marking a significant advance in personalized care for these high-risk diseases.

Establishment and characterization of 18 Sarcoma Cell Lines: Unraveling the Molecular Mechanisms of Doxorubicin Resistance in Sarcoma Cell Lines

Sarcomas, malignant tumors from mesenchymal tissues, exhibit poor prognosis despite advancements in treatment modalities such as surgery, radiotherapy, and chemotherapy, with doxorubicin being a cornerstone treatment. Resistance to doxorubicin remains a significant hurdle in therapy optimization. This study aims to dissect the molecular bases of doxorubicin resistance in sarcoma cell lines, which could guide the development of tailored therapeutic strategies. Eighteen sarcoma cell lines from 14 patients were established under ethical approvals and classified into seven subtypes. Molecular, genomic, and transcriptomic analyses included whole-exome sequencing, RNA sequencing, drug sensitivity assays, and pathway enrichment studies to elucidate the resistance mechanisms. Variability in doxorubicin sensitivity was linked to specific genetic alterations, including mutations in TP53 and variations in the copy number of genomic loci like 11q24.2. Transcriptomic profiling divided cell lines into clusters by karyotype complexity, influencing drug responses. Additionally, pathway analyses highlighted the role of signaling pathways like WNT/BETA-CATENIN and HEDGEHOG in doxorubicin-resistant lines. Comprehensive molecular profiling of sarcoma cell lines has revealed complex interplays of genetic and transcriptomic factors dictating doxorubicin resistance, underscoring the need for personalized medicine approaches in sarcoma treatment. Further investigations into these resistance mechanisms could facilitate the development of more effective, customized therapy regimens.

Avermectin B1 mediates antitumor activity and induces autophagy in osteosarcoma through the AMPK/ULK1 signaling pathway

BACKGROUND

Osteosarcoma is the most common malignant bone tumor in children and adolescents. Conventional chemotherapy remains unsatisfactory due to drug toxicity and resistance issues. Therefore, there is an urgent need to develop more effective treatments for advanced osteosarcoma. In the current study, we focused on evaluating the anticancer efficacy of avermectin B1, a novel avermectin analog, against osteosarcoma cells.

METHODS

The half-inhibitory concentration of avermectin B1 was calculated in three osteosarcoma cell lines. Then, functional experiments were conducted to evaluate the effects of avermectin B1 on cell proliferation, the cell cycle, apoptosis and autophagy. Moreover, the AMPK/ULK1 signaling pathway was detected by Western blot assay. Finally, the in vivo effect of avermectin B1 on tumor growth and metastasis was investigated using the xenograft mouse model. To examine the role of the AMPK/ULK1 pathway, an AMPK-specific inhibitor (dorsomorphin) was used in combination with avermectin B1.

RESULTS

Avermectin B1 inhibited the proliferation of osteosarcoma cells in a dose-dependent manner based on CCK8 and colony formation assays. Then, it was found to inhibit migration and invasion by wound healing assay and cell migration and invasion assay. In addition, avermectin B1 induced osteosarcoma cell apoptosis and autophagy. In vivo, avermectin B1 effectively inhibited osteosarcoma cell growth and pulmonary metastasis. Mechanistically, avermectin B1 activated the AMPK/ULK1 pathway to exert antitumor activity in vitro and in vivo. Dorsomorphin significantly attenuated the Avermectin B1-induced antitumor activities.

CONCLUSION

Our study suggests that avermectin B1 is a potential agent to treat osteosarcoma cells through the AMPK/ULK1 signaling pathway.

The application of lung immune prognostic index in predicting the prognosis of 302 STS patients

Background

Soft tissue sarcoma (STS) are heterogeneous and rare tumors, and few studies have explored predicting the prognosis of patients with STS. The Lung Immune Prognostic Index (LIPI), calculated based on baseline serum lactate dehydrogenase (LDH) and the derived neutrophils/(leukocytes minus neutrophils) ratio (dNLR), was considered effective in predicting the prognosis of patients with pulmonary cancer and other malignancies. However, the efficacy of the LIPI in predicting the prognosis of patients with STS remains unclear.

Methods

This study retrospectively reviewed patients with STS admitted to our center from January 2016 to January 2021. Their hematological and clinical characteristics were collected and analyzed to construct the LIPI specific to STS. The correlations between various predictive factors and overall survival (OS) were examined using Kaplan-Meier and Cox regression analyses. Independent risk factors for OS were identified using univariate and multivariate analyses. Finally, a LIPI nomogram model for STS was established.

Results

This study enrolled 302 patients with STS, of which 87 (28.9%), 162 (53.6%), and 53 (17.5%) were classified into three LIPI-based categories: good, moderate, and poor, respectively (P < 0.0001). The time-dependent operator curve showed that the LIPI had better prognostic predictive ability than other hematological and clinical characteristics. Univariate and multivariate analyses identified the Fédération Nationale des Centres de Lutte Contre le Cancer grade (FNCLCC/G), tumor size, and LIPI as independent risk factors. Finally, a nomogram was constructed by integrating the significant prognostic factors. Its C-index was 0.72, and the calibration curve indicated that it could accurately predict the three- and five-year OS of patients with STS. The decision and clinical impact curves also indicated that implementing this LIPI-nomogram could significantly benefit patients with STS.

Conclusion

This study explored the efficacy of the LIPI in predicting the prognosis of 302 patients with STS, classifying them into three categories to evaluate the prognosis. It also reconstructed a LIPI-based nomogram to assist clinicians in predicting the three- and five-year OS of patients with STS, potentially enabling timely intervention and customized management.

Development and experimental verification of novel angiogenesis related prognostic model and immune infiltration characterization in osteosarcoma

BACKGROUND

As the most common primary bone cancer, osteosarcoma (OS) still lacks satisfactory therapeutic outcomes. Therefore, it is crucial to further evaluate OS at different risk levels and identify new intervention targets. Many evidences suggest the important role of angiogenesis in OS, but further exploration is needed.

METHODS

We utilized public databases TARGET and GEO and employed bioinformatics algorithms such as LASSO, univariate and multivariate Cox regression analyses, and unsupervised consensus clustering to explore the role of angiogenesis-related genes (AGRGs) in OS. By calculating AGRG scores, we further analyzed OS molecular subtypes based on AGRGs. The correlation between AGRG scores and immune infiltration was subsequently examined. In vitro experiments, including WB, PCR, siRNA, migration, and invasion assays, were used to determine the value of the selected targets for OS.

RESULTS

Ultimately, we established an OS prognosis model based on five AGRGs (COL5A2, CXCL6, FSTL1, NRP1, and TNFRSF21) that can independently validate prognosis levels. In vitro experiments confirmed the aberrant expression of CXCL6 in OS and its potential role in migration and invasion.

CONCLUSION

Our study reveals the impact of angiogenesis on OS from a novel perspective and provides potential intervention targets.

S-p-bromobenzyl-glutathione cyclopentyl diester (BBGC) as novel therapeutic strategy to enhance trabectedin anti-tumor effect in soft tissue sarcoma preclinical models

Trabectedin, approved for the treatment of soft tissue sarcoma (STS), interferes with cell division and genetic transcription processes. Due to its strong anti-tumor activity in only certain histotypes, several studies on trabectedin combinations are currently ongoing to improve its efficacy. In this study, we aimed to investigate novel potential therapeutic strategies to enhance the anti-tumor effect of trabectedin using integrated in silico, in vitro, and in vivo approaches. For in silico analysis, we screened two public datasets, GSEA M5190 and TCGA SARC. Fibrosarcoma, leiomyosarcoma, dedifferentiated, and myxoid liposarcoma cell lines were used for in vitro studies. For in vivo experiments, fibrosarcoma orthotopic murine model was developed. In silico analysis identified Glo1 as the only druggable target upregulated after trabectedin treatment and correlated with poor prognosis. The specific Glo1 inhibitor, S-p-bromobenzylglutathione cyclopentyl diester (BBGC), increased trabectedin cytotoxicity in STS cells, and restored drug sensitivity in myxoid liposarcoma cells resistant to trabectedin. Moreover, the combined treatment with BBGC and trabectedin had a synergistic antitumor effect in vivo without any additional toxicity to mice. Based on these results, we believe that BBGC warrants further investigation to evaluate its potential clinical use in combination with trabectedin.

The molecular conversations of sarcomas: exosomal non-coding RNAs in tumor's biology and their translational prospects

Exosomes mediate cell-to-cell crosstalk involving a variety of biomolecules through an intricate signaling network. In recent years, the pivotal role of exosomes and their non-coding RNAs cargo in the development and progression of several cancer types clearly emerged. In particular, tumor bulk and its microenvironment co-evolve through cellular communications where these nanosized extracellular vesicles are among the most relevant actors. Knowledge about the cellular, and molecular mechanisms involved in these communications will pave the way for novel exosome-based delivery of therapeutic RNAs as well as innovative prognostic/diagnostic tools. Despite the valuable therapeutic potential and clinical relevance of exosomes, their role on sarcoma has been vaguely reported because the rarity and high heterogeneity of this type of cancer. Here, we dissected the scientific literature to unravel the multifaceted role of exosomal non-coding RNAs as mediator of cell-to-cell communications in the sarcoma subtypes.

Xenografting Human Musculoskeletal Sarcomas in Mice, Chick Embryo, and Zebrafish: How to Boost Translational Research

Musculoskeletal sarcomas pose major challenges to researchers and clinicians due to their rarity and heterogeneity. Xenografting human cells or tumor fragments in rodents is a mainstay for the generation of cancer models and for the preclinical trial of novel drugs. Lately, though, technical, intrinsic and ethical concerns together with stricter regulations have significantly curbed the employment of murine patient-derived xenografts (mPDX). In alternatives to murine PDXs, researchers have focused on embryonal systems such as chorioallantoic membrane (CAM) and zebrafish embryos. These systems are time- and cost-effective hosts for tumor fragments and near-patient cells. The CAM of the chick embryo represents a unique vascularized environment to host xenografts with high engraftment rates, allowing for ease of visualization and molecular detection of metastatic cells. Thanks to the transparency of the larvae, zebrafish allow for the tracking of tumor development and metastatization, enabling high-throughput drug screening. This review will focus on xenograft models of musculoskeletal sarcomas to highlight the intrinsic and technically distinctive features of the different hosts, and how they can be exploited to elucidate biological mechanisms beneath the different phases of the tumor's natural history and in drug development. Ultimately, the review suggests the combination of different models as an advantageous approach to boost basic and translational research.

Telomeres and telomerase in Sarcoma disease and therapy

Sarcoma is a rare tumor derived from the mesenchymal tissue and mainly found in children and adolescents. The outcome for patients with sarcoma is relatively poor compared with that for many other solid malignant tumors. Sarcomas have a highly heterogeneous pathogenesis, histopathology and biological behavior. Dysregulated signaling pathways and various gene mutations are frequently observed in sarcomas. The telomere maintenance mechanism (TMM) has recently been considered as a prognostic factor for patients with sarcomas, and alternative lengthening of telomeres (ALT) positivity has been correlated with poor outcomes in patients with several types of sarcomas. Therefore, telomeres and telomerases may be useful targets for treating sarcomas. This review aims to provide an overview of telomere and telomerase biology in sarcomas.

Pathogenetic and molecular classifications of soft tissue and bone tumors: A 2024 update

Soft tissue and bone tumors comprise a wide category of neoplasms. Their diversity frequently raises diagnostic challenges, and therapeutic options are continuously developing. The therapeutic success rate and long-term prognosis of patients have improved substantially due to new advances in immunohistochemical and molecular biology techniques. A fundamental contribution to these achievements has been the study of the tumor microenvironment and the reclassification of new entities with the updating of the molecular pathogenesis in the revised 5th edition of the Classification of Soft Tissue Tumors, edited by the World Health Organization. The proposed molecular diagnostic techniques include the well-known in situ hybridization and polymerase chain reaction methods, but new techniques such as copy-number arrays, multiplex probes, single-nucleotide polymorphism, and sequencing are also proposed. This review aims to synthesize the most recent pathogenetic and molecular classifications of soft tissue and bone tumors, considering the major impact of these diagnostic tools, which are becoming indispensable in clinicopathological practice.

Transcriptional regulation and therapeutic potential of cyclin-dependent kinase 9 (CDK9) in sarcoma

Sarcomas include various subtypes comprising two significant groups - soft tissue and bone sarcomas. Although the survival rate for some sarcoma subtypes has improved over time, the current methods of treatment remain efficaciously limited, as recurrent, and metastatic diseases remain a major obstacle. There is a need for better options and therapeutic strategies in treating sarcoma. Cyclin dependent kinase 9 (CDK9) is a transcriptional kinase and has emerged as a promising target for treating various cancers. The aberrant expression and activation of CDK9 have been observed in several sarcoma subtypes, including rhabdomyosarcoma, synovial sarcoma, osteosarcoma, Ewing sarcoma, and chordoma. Enhanced CDK9 expression has also been correlated with poorer prognosis in sarcoma patients. As a master regulator of transcription, CDK9 promotes transcription elongation by phosphorylation and releasing RNA polymerase II (RNAPII) from its promoter proximal pause. Release of RNAPII from this pause induces transcription of critical genes in the tumor cell. Overexpression and activation of CDK9 have been observed to lead to the expression of oncogenes, including MYC and MCL-1, that aid sarcoma development and progression. Inhibition of CDK9 in sarcoma has been proven to reduce these oncogenes' expression and decrease proliferation and growth in different sarcoma cells. Currently, there are several CDK9 inhibitors in preclinical and clinical investigations. This review aims to highlight the recent discovery and results on the transcriptional role and therapeutic potential of CDK9 in sarcoma.

Arid1a Loss Enhances Disease Progression in a Murine Model of Osteosarcoma

Osteosarcoma is an aggressive bone malignancy, molecularly characterized by acquired genome complexity and frequent loss of TP53 and RB1. Obtaining a molecular understanding of the initiating mutations of osteosarcomagenesis has been challenged by the difficulty of parsing between passenger and driver mutations in genes. Here, a forward genetic screen in a genetic mouse model of osteosarcomagenesis initiated by Trp53 and Rb1 conditional loss in pre-osteoblasts identified that Arid1a loss contributes to OS progression. Arid1a is a member of the canonical BAF (SWI/SNF) complex and a known tumor suppressor gene in other cancers. We hypothesized that the loss of Arid1a increases the rate of tumor progression and metastasis. Phenotypic evaluation upon in vitro and in vivo deletion of Arid1a validated this hypothesis. Gene expression and pathway analysis revealed a correlation between Arid1a loss and genomic instability, and the subsequent dysregulation of genes involved in DNA DSB or SSB repair pathways. The most significant of these transcriptional changes was a concomitant decrease in DCLRE1C. Our findings suggest that Arid1a plays a role in genomic instability in aggressive osteosarcoma and a better understanding of this correlation can help with clinical prognoses and personalized patient care.

Discordance Between the Initial Diagnosis of Sarcomas and Subsequent Histopathological Revision and Molecular Analyses in a Sarcoma Reference Center in Brazil

PURPOSE

To investigate the discordance in sarcoma diagnoses between nonspecialized institutions following revision by dedicated sarcoma pathologists at a reference center in Brazil and the relevance of molecular pathology in this context.

METHODS

We conducted a retrospective analysis of sarcoma samples initially analyzed at outside laboratories and subsequently reviewed by two specialized pathologists between January 2014 and December 2020. After obtaining demographic and tumor characteristics, pathology results were matched and classified as complete discordance (CD; benign v malignant, sarcoma v other malignancies), partial concordance (similar diagnosis of connective tumor, but different grade/histological subtype/differentiation), and complete concordance (CC). The concordance for histology or grade, and the role of molecular assessments supporting the diagnosis were also independently determined. Statistical analyses were conducted through the kappa coefficient of agreement and adherence by χ2 test, χ2 test by Person, and Fisher exact test.

RESULTS

In total, 197 cases were included, with samples obtained predominately from male patients (57.9%) and localized/primary tumors (86.8%). Following revision, the most frequent final diagnoses were undifferentiated pleomorphic sarcoma (17.8%), well-differentiated/dedifferentiated liposarcoma (8.6%), and leiomyosarcoma (7.6%). CD was found in 13.2%, partial discordance in 45.2%, and CC in 41.6% of reviews (P < .001). We found a concordance for histology or grade of 53.5% (P < .001) and 51.8% (P < .001), respectively. Molecular assessments, comprising next-generation sequencing panels (79.5%) and fluorescent in situ hybridization (20.5%), were performed in 44 (22.3%) cases, with findings classified as of diagnostic relevance in 31.8%.

CONCLUSION

In nearly 60% of the cases, the initial sarcoma diagnosis was modified when revised by a reference center and dedicated pathologists, assisted by molecular pathology techniques. These results justify the assembly of referral networks in countries with limited health care resources.

Stereotactic Body Radiation Therapy and Concurrent Targeted Therapy for Lung Metastases in Pediatric Sarcoma

Purpose

The purpose of this investigation was to evaluate the efficacy and safety of stereotactic body radiation therapy (SBRT) for pulmonary metastases from pediatric sarcomas.

Methods and Materials

This study was a single institutional retrospective chart review including patients younger than 21 years of age at diagnosis who had received SBRT for pulmonary metastasis from metastatic sarcoma. Our current electronic record system was queried for all eligible patients. Primary endpoint was tumor response as defined by Respone Evaluation Criteria in Solid Tumors 1.1 criteria. Secondarily, we analyzed factors that affected tumor response as well as toxicity of treatment. Median dose was 50 Gy ranging from 30 to 60 Gy in 5 fractions to the planning tumor volume.

Results

There were 7 patients, ranging in age from 6 to 21 years with a total of 14 pulmonary lesions treated with SBRT. Median and mean follow-up times for the 7 patients were 10.6 months and 15.9 months, respectively. The complete response rate was 50%, partial response 21%, stable disease 21%, and progressive disease 7%. Four of the 7 patients were treated with concurrent systemic therapy, 3 of which were targeted oral therapies. Additionally, we observed that patients who were on targeted therapy such as regorafenib or pazopanib seemed to have better local control compared with patients without targeted therapy.

Conclusions

With an overall response rate of 92%, SBRT provided a noninvasive effective palliative treatment option with few side effects in this small retrospective study of 7 patients. A larger prospective clinical trial is warranted to evaluate the role of SBRT in the treatment of unresectable metastatic pediatric sarcomas.

Advancing rare cancer research by MALDI mass spectrometry imaging: Applications, challenges, and future perspectives in sarcoma

MALDI mass spectrometry imaging (MALDI imaging) uniquely advances cancer research, by measuring spatial distribution of endogenous and exogenous molecules directly from tissue sections. These molecular maps provide valuable insights into basic and translational cancer research, including tumor biology, tumor microenvironment, biomarker identification, drug treatment, and patient stratification. Despite its advantages, MALDI imaging is underutilized in studying rare cancers. Sarcomas, a group of malignant mesenchymal tumors, pose unique challenges in medical research due to their complex heterogeneity and low incidence, resulting in understudied subtypes with suboptimal management and outcomes. In this review, we explore the applicability of MALDI imaging in sarcoma research, showcasing its value in understanding this highly heterogeneous and challenging rare cancer. We summarize all MALDI imaging studies in sarcoma to date, highlight their impact on key research fields, including molecular signatures, cancer heterogeneity, and drug studies. We address specific challenges encountered when employing MALDI imaging for sarcomas, and propose solutions, such as using formalin-fixed paraffin-embedded tissues, and multiplexed experiments, and considerations for multi-site studies and digital data sharing practices. Through this review, we aim to spark collaboration between MALDI imaging researchers and clinical colleagues, to deploy the unique capabilities of MALDI imaging in the context of sarcoma.

The bispecific B7H3xCD3 antibody CC-3 induces T cell immunity against bone and soft tissue sarcomas

Sarcomas are rare and heterogeneous malignancies that are difficult to treat. Approximately 50% of patients diagnosed with sarcoma develop metastatic disease with so far very limited treatment options. The transmembrane protein B7-H3 reportedly is expressed in various malignancies, including different sarcoma subtypes. In several cancer entities B7-H3 expression is associated with poor prognosis. In turn, B7-H3 is considered a promising target for immunotherapeutic approaches. We here report on the preclinical characterization of a B7-H3xCD3 bispecific antibody in an IgG-based format, termed CC-3, for treatment of different sarcoma subtypes. We found B7-H3 to be expressed on all sarcoma cells tested and expression on sarcoma patients correlated with decreased progression-free and overall survival. CC-3 was found to elicit robust T cell responses against multiple sarcoma subtypes, resulting in significant activation, release of cytokines and effector molecules. In addition, CC-3 promoted T cell proliferation and differentiation, resulting in the generation of memory T cell subsets. Finally, CC-3 induced potent target cell lysis in a target cell restricted manner. Based on these results, a clinical trial evaluating CC-3 in soft tissue sarcoma is currently in preparation.

Optical Genome Mapping for Comprehensive Cytogenetic Analysis of Soft-Tissue and Bone Tumors for Diagnostic Purposes

Soft-tissue and bone tumors represent a heterogeneous group of tumors encompassing more than 100 histologic subtypes today. Identifying genetic aberrations increasingly is important in these tumors for accurate diagnosis. Although gene mutations typically are detected by second-generation sequencing, the identification of structural variants (SVs) and copy number alterations (CNAs) remains challenging and requires various cytogenetic techniques including karyotyping, fluorescence in situ hybridization, and arrays, each with important limitations. Optical Genome Mapping (OGM), a non-sequencing-based technique for high-resolution detection of SVs and CNAs, was applied in a retrospective series of diagnostic soft-tissue and bone tumor samples. Sample preparation was successful in 38 of 53 cases, with the highest success rate in nonadipocytic soft-tissue tumors (24 of 27 cases; 89%). In 32 of 35 cases carrying a diagnostic SV or CNA, OGM identified the aberration (91%), including a POU2AF3::EWSR1 fusion in a round cell sarcoma and a translocation t(1;5)(p22;p15) in a myxoinflammatory fibroblastic sarcoma. Interestingly, OGM shed light on the genomic complexity underlying the various aberrations. In five samples, OGM showed that chains of rearrangements generated the diagnostic fusion, three of which involved chromoplexy. In addition, in nine samples, chromothripsis was causal to the formation of giant marker/ring/double-minute chromosomes. Finally, compared with standard-of-care cytogenetics, OGM revealed additional aberrations, requiring further investigation of their potential clinical relevance.

Neoadjuvant Therapies Do Not Reduce Epidermal Growth Factor Receptor (EGFR) Expression or EGFR-Targeted Fluorescence in a Murine Model of Soft-Tissue Sarcomas

PURPOSE

ABY-029, an epidermal growth factor receptor (EGFR)-targeted, synthetic Affibody peptide labeled with a near-infrared fluorophore, is under investigation for fluorescence-guided surgery of sarcomas. To date, studies using ABY-029 have occurred in tumors naïve to chemotherapy (CTx) and radiation therapy (RTx), although these neoadjuvant therapies are frequently used for sarcoma treatment in humans. The goal of this study was to evaluate the impact of CTx and RTx on tumor EGFR expression and ABY-029 fluorescence of human soft-tissue sarcoma xenografts in a murine model.

PROCEDURES

Immunodeficient mice (n = 98) were divided into five sarcoma xenograft groups and three treatment groups - CTx only, RTx only, and CTx followed by RTx, plus controls. Four hours post-injection of ABY-029, animals were sacrificed followed by immediate fluorescence imaging of ex vivo adipose, muscle, nerve, and tumor tissues. Histological hematoxylin and eosin staining confirmed tumor type, and immunohistochemistry staining determined EGFR, cluster of differentiation 31 (CD31), and smooth muscle actin (SMA) expression levels. Correlation analysis (Pearson's correlation coefficients, r) and linear regression (unstandardized coefficient estimates, B) were used to determine statistical relationships in molecular expression and tissue fluorescence between xenografts and treatment groups.

RESULTS

Neoadjuvant therapies had no broad impact on EGFR expression (|B|≤ 7.0, p ≥ 0.4) or on mean tissue fluorescence (any tissue type, (|B|≤ 2329.0, p ≥ 0.1). Mean tumor fluorescence was significantly related to EGFR expression (r = 0.26, p = 0.01), as expected.

CONCLUSION

Results suggest that ABY-029 as an EGFR-targeted, fluorescent probe is not negatively impacted by neoadjuvant soft-tissue sarcoma therapies, although validation in humans is required.

A personalized medicine approach identifies enasidenib as an efficient treatment for IDH2 mutant chondrosarcoma

BACKGROUND

Sarcomas represent an extensive group of malignant diseases affecting mesodermal tissues. Among sarcomas, the clinical management of chondrosarcomas remains a complex challenge, as high-grade tumours do not respond to current therapies. Mutations in the isocitrate dehydrogenase (IDH) 1 and 2 genes are among the most common mutations detected in chondrosarcomas and may represent a therapeutic opportunity. The presence of mutated IDH (mIDH) enzymes results in the accumulation of the oncometabolite 2-HG leading to molecular alterations that contribute to drive tumour growth.

METHODS

We developed a personalized medicine strategy based on the targeted NGS/Sanger sequencing of sarcoma samples (n = 6) and the use of matched patient-derived cell lines as a drug-testing platform. The anti-tumour potential of IDH mutations found in two chondrosarcoma cases was analysed in vitro, in vivo and molecularly (transcriptomic and DNA methylation analyses).

FINDINGS

We treated several chondrosarcoma models with specific mIDH1/2 inhibitors. Among these treatments, only the mIDH2 inhibitor enasidenib was able to decrease 2-HG levels and efficiently reduce the viability of mIDH2 chondrosarcoma cells. Importantly, oral administration of enasidenib in xenografted mice resulted in a complete abrogation of tumour growth. Enasidenib induced a profound remodelling of the transcriptomic landscape not associated to changes in the 5 mC methylation levels and its anti-tumour effects were associated with the repression of proliferative pathways such as those controlled by E2F factors.

INTERPRETATION

Overall, this work provides preclinical evidence for the use of enasidenib to treat mIDH2 chondrosarcomas.

FUNDING

Supported by the Spanish Research Agency/FEDER (grants PID2022-142020OB-I00; PID2019-106666RB-I00), the ISC III/FEDER (PI20CIII/00020; DTS18CIII/00005; CB16/12/00390; CB06/07/1009; CB19/07/00057); the GEIS group (GEIS-62); and the PCTI (Asturias)/FEDER (IDI/2021/000027).

The Rat Sarcoma Virus (RAS) Family of Proteins in Sarcomas

The rat sarcoma virus (RAS) protein family plays a crucial role in facilitating communication both within and between cells, thereby governing fundamental cellular processes such as growth, survival, and differentiation. The RAS family comprises four members of small GTPases, namely Harvey RAS (H-RAS), Kirsten RAS (K-RAS, two splice variants, 4A and 4B), and Neuroblastoma RAS (N-RAS), and these are encoded by three cellular RAS genes. Mutations in these genes play a significant role in cancer development and progression. Accordingly, here we review and discuss currently available literature about the fate and function of the RAS family of proteins in sarcomas.

CDK4/6 Inhibition With Lerociclib is a Potential Therapeutic Strategy for the Treatment of Pediatric Sarcomas

BACKGROUND

Sarcomas are a heterogenous collection of bone and soft tissue tumors. The heterogeneity of these tumors makes it difficult to standardize treatment. CDK 4/6 inhibitors are a family of targeted agents which limit cell cycle progression and have been shown to be upregulated in sarcomas. In the current preclinical study, we evaluated the effects of lerociclib, a CDK4/6 inhibitor, on pediatric sarcomas in vitro and in 3D bioprinted tumors.

METHODS

The effects of lerociclib on viability, proliferation, cell cycle, motility, and stemness were assessed in established sarcoma cell lines, U-2 OS and MG-63, as well as sarcoma patient-derived xenografts (PDXs). 3D printed biotumors of each of the U-2 OS, MG-63, and COA79 cells were utilized to study the effects of lerociclib on tumor growth ex vivo.

RESULTS

CDK 4/6, as well as the intermediaries retinoblastoma protein (Rb) and phosphorylated Rb were identified as targets in the four sarcoma cell lines. Lerociclib treatment induced cell cycle arrest, decreased proliferation, motility, and stemness of sarcoma cells. Treatment with lerociclib decreased sarcoma cell viability in both traditional 2D culture as well as 3D bioprinted microtumors.

CONCLUSIONS

Inhibition of CDK 4/6 activity with lerociclib was efficacious in traditional 2D sarcoma cell culture as well as in 3D bioprints. Lerociclib holds promise and warrants further investigation as a novel therapeutic strategy for management of these heterogenous groups of tumors.

Identification of MCM4 and PRKDC as new regulators of osteosarcoma cell dormancy based on 3D cell cultures

Dormancy is a potential way for tumors to develop drug resistance and escape treatment. However, the mechanisms involved in cancer dormancy remain poorly understood. This is mainly because there is no in vitro culture model making it possible to spontaneously induce dormancy. In this context, the present work proposes the use of three-dimensional (3D) spheroids developed from osteosarcoma cell lines as a relevant model for studying cancer dormancy. MNNG-HOS, SaOS-2, 143B, MG-63, U2OS and SJSA-1 cell lines were cultured in 3D using the Liquid Overlay Technique (LOT). Dormancy was studied by staining cancer cells with a lipophilic dye (DiD), and long-term DiD+ cells were considered as dormant cancer cells. The role of the extracellular matrix in inducing dormancy was investigated by embedding cells into methylcellulose or Geltrex™. Gene expression of DiD+ cells was assessed with a Nanostring™ approach and the role of the genes detected in dormancy was validated by a transient down-expression model using siRNA treatment. Proliferation was measured using fluorescence microscopy and the xCELLigence technology. We observed that MNNG-HOS, 143B and MG-G3 cell lines had a reduced proliferation rate in 3D compared to 2D. U2OS cells had an increased proliferation rate when they were cultured in Geltrex™ compared to other 3D culture methods. Using 3D cultures, a transcriptomic signature of dormancy was obtained and showed a decreased expression of 18 genes including ETV4, HELLS, ITGA6, MCM4, PRKDC, RAD21 and UBE2T. The treatment with siRNA targeting these genes showed that cancer cell proliferation was reduced when the expression of ETV4 and MCM4 were decreased, whereas proliferation was increased when the expression of RAD21 was decreased. 3D culture facilitates the maintenance of dormant cancer cells characterized by a reduced proliferation and less differential gene expression as compared to proliferative cells. Further studies of the genes involved has enabled us to envisage their role in regulating cell proliferation.

Outcome of Endoprosthesis used in Limb Salvage Surgery in a Malaysian Orthopaedic Oncology Centre

Introduction

To describe the duration of survival among bone tumour patients with endoprosthesis reconstruction and to determine frequency of implant failure, revision of surgery, and amputation after endoprosthesis reconstruction.

Materials and methods

A retrospective cross-sectional review of all patients with either primary bone tumour or secondary bone metastases treated with en bloc resection and endoprosthesis reconstruction from January 2008 to December 2020.

Results

A total of 35 failures were recorded among the 27 (48.2%) patients with endoprostheses. Some of the patients suffered from one to three types of modes of failure on different timelines during the course of the disease. Up to eight patients suffered from more than one type of failure throughout the course of the disease. Out of all modes of failure, local recurrence (type 5 failure) was the most common, accounting for 25.0% of all failure cases. Four patients (7.1%) eventually underwent amputation, which were either due to infection (2 patients) or disease progression causing local recurrence (2 patients).

Conclusion

The overall result of endoprosthesis reconstruction performed in our centre was compatible with other centres around the world. Moreover, limb salvage surgery should be performed carefully in a selected patient group to maximise the benefits of surgery.

SQLE is a promising prognostic and immunological biomarker and correlated with immune Infiltration in Sarcoma

Squalene epoxidase (SQLE) is an essential enzyme involved in cholesterol biosynthesis. However, its role in sarcoma and its correlation with immune infiltration remains unclear. All original data were downloaded from The Cancer Genome Atlas (TCGA). SQLE expression was explored using the TCGA database, and correlations between SQLE and cancer immune characteristics were analyzed via the TISIDB databases. Generally, SQLE is predominantly overexpressed and has diagnostic and prognostic value in sarcoma. Upregulated SQLE was associated with poorer overall survival, poorer disease-specific survival, and tumor multifocality in sarcoma. Mechanistically, we identified a hub gene that included a total of 82 SQLE-related genes, which were tightly associated with histone modification pathways in sarcoma patients. SQLE expression was negatively correlated with infiltrating levels of dendritic cells and plasmacytoid dendritic cells and positively correlated with Th2 cells. SQLE expression was negatively correlated with the expression of chemokines (CCL19 and CX3CL1) and chemokine receptors (CCR2 and CCR7) in sarcoma. In conclusion, SQLE may be used as a prognostic biomarker for determining prognosis and immune infiltration in sarcoma.

In-Silico Identification of Novel Pharmacological Synergisms: The Trabectedin Case

The in-silico strategy of identifying novel uses for already existing drugs, known as drug repositioning, has enhanced drug discovery. Previous studies have shown a positive correlation between expression changes induced by the anticancer agent trabectedin and those caused by irinotecan, a topoisomerase I inhibitor. Leveraging the availability of transcriptional datasets, we developed a general in-silico drug-repositioning approach that we applied to investigate novel trabectedin synergisms. We set a workflow allowing the identification of genes selectively modulated by a drug and possible novel drug interactions. To show its effectiveness, we selected trabectedin as a case-study drug. We retrieved eight transcriptional cancer datasets including controls and samples treated with trabectedin or its analog lurbinectedin. We compared gene signature associated with each dataset to the 476,251 signatures from the Connectivity Map database. The most significant connections referred to mitomycin-c, topoisomerase II inhibitors, a PKC inhibitor, a Chk1 inhibitor, an antifungal agent, and an antagonist of the glutamate receptor. Genes coherently modulated by the drugs were involved in cell cycle, PPARalpha, and Rho GTPases pathways. Our in-silico approach for drug synergism identification showed that trabectedin modulates specific pathways that are shared with other drugs, suggesting possible synergisms.