Slit2 signaling stimulates Ewing sarcoma growth

Multi-omics profiling reveals key factors involved in Ewing sarcoma metastasis

Ewing sarcoma (EWS) is the second most common bone tumor affecting children and young adults, with dismal outcomes for patients with metastasis at diagnosis. Mechanisms leading to metastasis remain poorly understood. To deepen our knowledge on EWS progression, we have profiled tumors and metastases from a spontaneous metastasis mouse model using a multi-omics approach. Combining transcriptomics, proteomics, and methylomics analyses, we identified signaling cascades and candidate genes enriched in metastases that could be modulating aggressiveness in EWS. Phenotypical validation of two of these candidates, cyclic AMP-responsive element-binding protein 1 (CREB1) and lipoxygenase homology domain-containing protein 1 (LOXHD1), showed an association with migration and clonogenic abilities. Moreover, previously described CREB1 downstream targets were present amongst the metastatic-enriched results. Combining the different omics datasets, we identified FYVE, RhoGEF, and PH domain-containing protein 4 (FGD4) as a CREB1 target interconnecting the different EWS biological layers (RNA, protein and methylation status) and whose high expression is associated with worse clinical outcome. Further studies will provide insight into EWS metastasis mechanisms and ultimately improve survival rates for EWS patients.

Ceramide-induced cleavage of GPR64 intracellular domain drives Ewing sarcoma

Ewing sarcoma is a cancer of bone and soft tissue in children and young adults primarily driven by the EWS-FLI1 fusion oncoprotein, which has been undruggable. Here, we report that Ewing sarcoma depends on secreted sphingomyelin phosphodiesterase 1 (SMPD1), a ceramide-generating enzyme, and ceramide. We find that G-protein-coupled receptor 64 (GPR64)/adhesion G-protein-coupled receptor G2 (ADGRG2) responds to ceramide and mediates critical growth signaling in Ewing sarcoma. We show that ceramide induces the cleavage of the C-terminal intracellular domain of GPR64, which translocates to the nucleus and restrains the protein levels of RIF1 in a manner dependent on SPOP, a substrate adaptor of the Cullin3-RING E3 ubiquitin ligase. We demonstrate that both SMPD1 and GPR64 are transcriptional targets of EWS-FLI1, indicating that SMPD1 and GPR64 are EWS-FLI1-induced cytokine-receptor dependencies. These results reveal the SMPD1-ceramide-GPR64 pathway, which drives Ewing sarcoma growth and is amenable to therapeutic intervention.

Magnetic nanomagnetic nanoparticles combining with Slit2 gene and bone marrow mononuclear cells to improve cognitive dysfunction in rats with chronic cerebral ischemia

Purpose: Cognitive dysfunction caused by chronic cerebral hypoperfusion (CCH) is the leading cause of vascular dementia. Therefore, it is necessary to explore the mechanism that causes cerebral injury and find an effective therapy. Methods: Bone marrow mononuclear cells (BMMNCs) were extracted to detect the activity by CCK-8 kit and verify the transfection efficiency using reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). A CCH rat model was established. Superparamagnetic iron oxide nanoparticles (BMPs)-PEI-Slit2/BMMNCs were injected into the tail vein and intervened with an external magnetic field. Hematoxylin and eosin staining was used to observe the pathological changes in brain tissue. The Slit/Robo pathway-related proteins Slit2 and Robo4 were detected by RT-qPCR and Western blotting. Results: The neurological score of the CCH group significantly increased compared with that of the sham group (P<0.05). The levels of brain injury markers S-100β and NSE were significantly higher in the CCH group than in the sham group (P<0.05). Neuronal apoptosis in the frontal cortex and hippocampus of CCH rats significantly increased compared with that of the sham group (P<0.05). The expression levels of Slit2 and Robo4 mRNAs and proteins in brain tissue of CCH rats significantly increased (P<0.05). The neurological function scores of CCH rats treated with BMP-PEI-Slit2/BMMNC significantly increased after Robo4 siRNA administration (P<0.05). Conclusion: BMP combination with the CCH-related gene Slit2 can effectively improve the efficiency of BMMNC transplantation in treatment.

Comprehensive Transcriptomic Analysis of EWSR1::WT1 Targets Identifies CDK4/6 Inhibitors as an Effective Therapy for Desmoplastic Small Round Cell Tumors

Desmoplastic small round cell tumors (DSRCT) are a type of aggressive, pediatric sarcoma characterized by the EWSR1::WT1 fusion oncogene. Targeted therapies for DSRCT have not been developed, and standard multimodal therapy is insufficient, leading to a 5-year survival rate of only 15% to 25%. Here, we depleted EWSR1::WT1 in DSRCT and established its essentiality in vivo. Transcriptomic analysis revealed that EWSR1::WT1 induces unique transcriptional alterations compared with WT1 and other fusion oncoproteins and that EWSR1::WT1 binding directly mediates gene upregulation. The E-KTS isoform of EWSR1::WT1 played a dominant role in transcription, and it bound to the CCND1 promoter and stimulated DSRCT growth through the cyclin D-CDK4/6-RB axis. Treatment with the CDK4/6 inhibitor palbociclib successfully reduced growth in two DSRCT xenograft models. As palbociclib has been approved by the FDA for the treatment of breast cancer, these findings demonstrate the sensitivity of DSRCT to palbociclib and support immediate clinical investigation of palbociclib for treating this aggressive pediatric cancer.

SIGNIFICANCE

EWSR1::WT1 is essential for desmoplastic small round cell tumors and upregulates the cyclin D-CDK4/6-RB axis that can be targeted with palbociclib, providing a targeted therapeutic strategy for treating this deadly tumor type.

Roles of USP1 in Ewing sarcoma

Ewing sarcoma is a cancer of bone and soft tissue in children and young adults that is driven by the EWS-ETS fusion transcription factor, most commonly EWS-FLI1. We previously reported that Ewing sarcoma harbors two populations of cells, the CD133high population displaying higher growth rate and the CD133low population displaying chemotherapy resistance. We now find that the ubiquitin-specific protease 1 (USP1) is a transcriptional target of the EWS-FLI1 fusion oncoprotein, expressed at high and low levels in the CD133high and the CD133low populations, respectively, and determines chemo-sensitivity. We also find that USP1 inhibits cdc42, increases EWS-FLI1 transcriptional output, and simulates Ewing sarcoma growth. We show that chemo-sensitization by USP1 is independent of cdc42. A pharmacological inhibitor of USP1 was able to activate cdc42 and inhibit Ewing sarcoma growth. These results uncover critical roles for USP1 in Ewing sarcoma, which regulates growth and chemo-sensitivity via distinct mechanisms.

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

Background

Ewing sarcoma (ES) is a common primary bone tumor in children. Our study aimed to compare overall survival (OS) between pediatric and adult bone ES patients, identify independent prognostic factors and develop a nomogram for predicting OS in adult patients with ES of bone.

Methods

We retrospectively analyzed data for the 2004-2015 period from the Surveillance, Epidemiology, and End Results (SEER) database. To guarantee well-balanced characteristics between the comparison groups, propensity score matching (PSM) was used. Kaplan-Meier (KM) curves were used to compare OS between pediatric and adult patients with ES of bone. Univariate and multivariate Cox regression analyses were used to screen independent prognostic factors for ES of bone, and a prognostic nomogram was constructed by using the factors identified. The prediction accuracy and clinical benefit were evaluated using receiver operating characteristic (ROC) curves, areas under the curves (AUCs), calibration curves, and decision curve analysis (DCA).

Results

Our results showed that adult ES patients had lower OS than younger ES patients. Age, surgery, chemotherapy, and TNM stage were independent risk factors for bone ES in adults and were used to develop a nomogram. AUCs for 3-, 5-, and 10-year OS were 76.4 (67.5, 85.3), 77.3 (68.6, 85.9) and 76.6 (68.6, 84.5), respectively. Calibration curves and DCA results indicated excellent performance for our nomogram.

Conclusion

We found that ES pediatric patients have better OS than adult ES patients, and we constructed a practical nomogram to predict the 3-, 5- and 10-year OS of adult patients with ES of bone based on independent prognostic factors (age, surgery, chemotherapy, T stage, N stage and M stage).

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.