CD99 contributes to the EWS::FLI1 transcriptome by specifically affecting FOXM1-targets involved in the G2/M cell cycle phase, thus influencing the Ewing sarcoma genetic landscape.

Ewing sarcoma (EwS), a highly aggressive malignancy affecting children and young adults, is primarily driven by a distinctive oncogenic fusion, the EWSR1-ETS, whose activity is a key source of epigenetic and clinical heterogeneity. CD99 is constantly present in EwS cells, known to modulate the EwS genetic profile and tumor malignancy. However, the relevance of CD99 alone, or in association with EWSR1-ETS chimeras, is poorly understood.

Single-nucleotide polymorphism profiling by multimodal-targeted next-generation sequencing in methotrexate-resistant and -sensitive human osteosarcoma cell lines.

Methotrexate (MTX) is one of the most important drugs included in the first-line protocols to treat high-grade osteosarcoma (HGOS). Although several polymorphisms have been reported to be associated with drug response or MTX-related toxicity in pharmacogenetic studies, their role in the development of MTX resistance in HGOS is still unclear. Therefore, in this study, 22 single nucleotide polymorphisms (SNPs) in 4 genes of the folate metabolism, 7 MTX transporter genes, and 2 SNPs of the tumor protein p53 () gene were investigated using a custom multimodal-targeted next-generation sequencing (mmNGS) approach in 8 MTX-resistant and 12 MTX-sensitive human HGOS cell lines.

Engagement of CD99 Activates Distinct Programs in Ewing Sarcoma and Macrophages.

Ewing sarcoma (EWS) is the second most common pediatric bone tumor. The EWS tumor microenvironment is largely recognized as immune-cold, with macrophages being the most abundant immune cells and their presence associated with worse patient prognosis. Expression of CD99 is a hallmark of EWS cells, and its targeting induces inhibition of EWS tumor growth through a poorly understood mechanism.

Polymorphic variants of and have an impact on predisposition and/or progression of Ewing sarcoma.

Ewing sarcoma (EWS), the second most common malignant bone tumor in children and adolescents, occurs abruptly without clear evidence of tumor history or progression. Previous association studies have identified some inherited variants associated with the risk of developing EWS but a common picture of the germline susceptibility to this tumor remains largely unclear. Here, we examine the association between thirty single nucleotide polymorphisms (SNPs) of the , a gene that codes for an oncofetal RNA-binding protein demonstrated to be important for EWS patient's risk stratification, and five SNPs of , a long non-coding RNA shown to regulate .

A 3D Collagen-Based Bioprinted Model to Study Osteosarcoma Invasiveness and Drug Response.

The biological and therapeutic limits of traditional 2D culture models, which only partially mimic the complexity of cancer, have recently emerged. In this study, we used a 3D bioprinting platform to process a collagen-based hydrogel with embedded osteosarcoma (OS) cells. The human OS U-2 OS cell line and its resistant variant (U-2OS/CDDP 1 μg) were considered.

ABCA6 affects the malignancy of Ewing sarcoma cells via cholesterol-guided inhibition of the IGF1R/AKT/MDM2 axis.

Purpose: The relevance of the subfamily A members of ATP-binding cassette (ABCA) transporters as biomarkers of risk and response is emerging in different tumors, but their mechanisms of action have only been partially defined. In this work, we investigated their role in Ewing sarcoma (EWS), a pediatric cancer with unmet clinical issues.

Methods: The expression of ABC members was evaluated by RT-qPCR in patients with localized EWS.

Bone Turnover Marker (BTM) Changes after Denosumab in Giant Cell Tumors of Bone (GCTB): A Phase II Trial Correlative Study.

Background: Giant cell tumors of bone (GCTB) are osteolytic tumors. Denosumab, a RANK-L inhibitor, is approved for GCTB. Data on serum bone turnover marker (sBTM) changes are lacking.

miR-214-3p Is Commonly Downregulated by EWS-FLI1 and by CD99 and Its Restoration Limits Ewing Sarcoma Aggressiveness.

Ewing's sarcoma (EWS), an aggressive pediatric bone and soft-tissue sarcoma, has a very stable genome with very few genetic alterations. Unlike in most cancers, the progression of EWS appears to depend on epigenetic alterations. EWS-FLI1 and CD99, the two hallmarks of EWS, are reported to severely impact the malignancy of EWS cells, at least partly by regulating the expression of several types of non-coding RNAs.

Integrated Molecular Characterization of Patient-Derived Models Reveals Therapeutic Strategies for Treating CIC-DUX4 Sarcoma.

Unlabelled: Capicua-double homeobox 4 (CIC-DUX4)-rearranged sarcomas (CDS) are extremely rare, highly aggressive primary sarcomas that represent a major therapeutic challenge. Patients are treated according to Ewing sarcoma protocols, but CDS-specific therapies are strongly needed. In this study, RNA sequencing was performed on patient samples to identify a selective signature that differentiates CDS from Ewing sarcoma and other fusion-driven sarcomas.

Targeting CD99 Compromises the Oncogenic Effects of the Chimera EWS-FLI1 by Inducing Reexpression of Zyxin and Inhibition of GLI1 Activity.

Ewing sarcoma, a highly aggressive pediatric tumor, is driven by EWS-FLI1, an oncogenic transcription factor that remodels the tumor genetic landscape. Epigenetic mechanisms play a pivotal role in Ewing sarcoma pathogenesis, and the therapeutic value of compounds targeting epigenetic pathways is being identified in preclinical models. Here, we showed that modulation of CD99, a cell surface molecule highly expressed in Ewing sarcoma cells, may alter transcriptional dysregulation in Ewing sarcoma through control of the zyxin-GLI1 axis.

Impact of ABC Transporters in Osteosarcoma and Ewing's Sarcoma: Which Are Involved in Chemoresistance and Which Are Not?

The ATP-binding cassette (ABC) transporter superfamily consists of several proteins with a wide repertoire of functions. Under physiological conditions, ABC transporters are involved in cellular trafficking of hormones, lipids, ions, xenobiotics, and several other molecules, including a broad spectrum of chemical substrates and chemotherapeutic drugs. In cancers, ABC transporters have been intensely studied over the past decades, mostly for their involvement in the multidrug resistance (MDR) phenotype.

ROCK2 deprivation leads to the inhibition of tumor growth and metastatic potential in osteosarcoma cells through the modulation of YAP activity.

Background: The treatment of metastatic osteosarcoma (OS) remains a challenge for oncologists, and novel therapeutic strategies are urgently needed. An understanding of the pathways that regulate OS dissemination is required for the design of novel treatment approaches. We recently identified Rho-associated coiled-coil containing protein kinase 2 (ROCK2) as a crucial driver of OS cell migration.

The ABC subfamily A transporters: Multifaceted players with incipient potentialities in cancer.

Overexpression of ATP-binding cassette (ABC) transporters is a cause of drug resistance in a plethora of tumors. More recent evidence indicates additional contribution of these transporters to other processes, such as tumor cell dissemination and metastasis, thereby extending their possible roles in tumor progression. While the role of some ABC transporters, such as ABCB1, ABCC1 and ABCG2, in multidrug resistance is well documented, the mechanisms by which ABC transporters affect the proliferation, differentiation, migration and invasion of cancer cells are still poorly defined and are frequently controversial.

Bone sarcoma patient-derived xenografts are faithful and stable preclinical models for molecular and therapeutic investigations.

Standard therapy of osteosarcoma (OS) and Ewing sarcoma (EW) rests on cytotoxic regimes, which are largely unsuccessful in advanced patients. Preclinical models are needed to break this impasse. A panel of patient-derived xenografts (PDX) was established by implantation of fresh, surgically resected osteosarcoma (OS) and Ewing sarcoma (EW) in NSG mice.

Construction of Human Naïve Antibody Gene Libraries.

Size and variability often represent an obstacle in generating an effective antibody gene library for the detection of an abundant repertoire of antigens. Therefore, optimizing the construction of a large library is essential for the selection of high-affinity reactive fragments. Here, we report a highly efficient method for the construction of a human naïve antibody gene library for the selection of antibodies as single-chain variable fragments.

A Quinoline-Based DNA Methyltransferase Inhibitor as a Possible Adjuvant in Osteosarcoma Therapy.

The identification of new therapeutic strategies against osteosarcoma, the most common primary bone tumor, continues to be a primary goal to improve the outcomes of patients refractory to conventional chemotherapy. Osteosarcoma originates from the transformation of mesenchymal stem cells (MSC) and/or osteoblast progenitors, and the loss of differentiation is a common biological osteosarcoma feature, which has strong significance in predicting tumor aggressiveness. Thus, restoring differentiation through epigenetic reprogramming is potentially exploitable for therapeutic benefits.

Insulin-Like Growth Factor 2 mRNA-Binding Protein 3 Influences Sensitivity to Anti-IGF System Agents Through the Translational Regulation of .

Insulin-like growth factor 2 (IGF2) mRNA-binding protein 3 (IGF2BP3) is an oncofetal protein that binds RNA, thereby influencing the fate of target transcripts. IGF2BP3 is synthesized in cancer, where it promotes proliferation, drug resistance, and metastasis both IGF2-dependent and IGF2-independent mechanisms. Ewing sarcoma (ES) is a rare bone and soft tissue tumor in which the IGF system plays a pivotal role.

Insulin-Like Growth Factor 2 mRNA-Binding Protein 3 is a Novel Post-Transcriptional Regulator of Ewing Sarcoma Malignancy.

Large-scale sequencing studies have indicated that besides genomic alterations, the posttranscriptional regulation of gene expression or epigenetic mechanisms largely influences the clinical behavior of Ewing sarcoma. We investigated the significance of the RNA-binding protein IGF2BP3 in the regulation of Ewing sarcoma aggressiveness. Explorative study was performed in 14 patients with localized Ewing sarcoma using RNA sequencing.

CD99: A Cell Surface Protein with an Oncojanus Role in Tumors.

The cell surface molecule CD99 has gained interest because of its involvement in regulating cell differentiation and adhesion/migration of immune and tumor cells. However, the molecule plays an intriguing and dual role in different cell types. In particular, it acts as a requirement for cell malignancy or as an oncosuppressor in tumors.

CD99 at the crossroads of physiology and pathology.

CD99 is a cell surface protein with unique features and only partly defined mechanisms of action. This molecule is involved in crucial biological processes, including cell adhesion, migration, death, differentiation and diapedesis, and it influences processes associated with inflammation, immune responses and cancer. CD99 is frequently overexpressed in many types of tumors, particularly pediatric tumors including Ewing sarcoma and specific subtypes of leukemia.

CD99 triggering induces methuosis of Ewing sarcoma cells through IGF-1R/RAS/Rac1 signaling.

CD99 is a cell surface molecule that has emerged as a novel target for Ewing sarcoma (EWS), an aggressive pediatric bone cancer. This report provides the first evidence of methuosis in EWS, a non-apoptotic form of cell death induced by an antibody directed against the CD99 molecule. Upon mAb triggering, CD99 induces an IGF-1R/RAS/Rac1 complex, which is internalized into RAB5-positive endocytic vacuoles.

Design and construction of a new human naïve single-chain fragment variable antibody library, IORISS1.

Human monoclonal antibodies are a powerful tool with increasingly successful exploitations and the single chain fragment variable format can be considered the building block for the implementation of more complex and effective antibody-based constructs. Phage display is one of the best and most efficient methods to isolate human antibodies selected from an efficient and variable phage display library. We report a method for the construction of a human naïve single-chain variable fragment library, termed IORISS1.

Process development of a human recombinant diabody expressed in E. coli: engagement of CD99-induced apoptosis for target therapy in Ewing's sarcoma.

Ewing's sarcoma (EWS) is the second most common primary bone tumor in pediatric patients characterized by over expression of CD99. Current management consists in extensive chemotherapy in addition to surgical resection and/or radiation. Recent improvements in treatment are still overshadowed by severe side effects such as toxicity and risk of secondary malignancies; therefore, more effective strategies are urgently needed.