Biology subjects

Danielli, S. G.

Publications and source records attributed to Danielli, S. G..

4 recordsLinked to original sources

bioRxiv2026

L1CAM-CAR T cells with enhanced potency overcome low-density antigen expression in rhabdomyosarcoma

Rhabdomyosarcoma (RMS), the most common pediatric soft tissue sarcoma, shows dismal survival in relapsed or metastatic alveolar disease. Chimeric antigen receptor (CAR) T cells are promising but limited by scarce tumor-selective antigens and suboptimal efficacy at low antigen density. We investigated L1 cell adhesion molecule (L1CAM) as a therapeutic target by profiling its expression by flow cytometry, immunoblotting, and immunohistochemistry in cell lines, patient-derived xenografts, and healthy tissues. Using the scFv derived from the CE7 antibody, we engineered L1CAM-CARs with distinct hinge and costimulatory domains and tested them in vitro and in orthotopic RMS mouse models against clinically tested CE7- and B7-H3-CARs. L1CAM was consistently expressed at moderate levels in RMS, especially alveolar subtypes, but very weakly expressed in healthy tissues. Flow cytometry revealed a moderate density typically limiting CAR activity. Among constructs, L1CAM.III (CE7-CAR with long hinge and CD28 domain) showed the strongest cytotoxicity and IFN-{gamma} release. In vivo, L1CAM.III-CAR T cells regressed tumors, prolonged survival, and persisted in orthotopic RMS models, showing greater efficacy in alveolar RMS and no off-tumor activity. These findings establish L1CAM as a rational RMS therapeutic target. Optimized L1CAM.III-CAR T cells overcome moderate antigen density, achieving potent and persistent antitumor activity comparable to B7-H3-CARs but with improved safety. This work supports CAR optimization for clinical translation to broaden pediatric sarcoma immunotherapy.

cancer biology↗

bioRxiv2024

Single-cell multidimensional profiling of tumor cell heterogeneity in supratentorial ependymomas

Supratentorial ependymomas are aggressive childhood brain cancers that retain features of neurodevelopmental cell types and segregate into molecularly and clinically distinct subgroups, suggesting different developmental roots. The developmental signatures as well as microenvironmental factors underlying aberrant cellular transformation and behavior across each supratentorial ependymoma subgroup are unknown. Here we integrated single cell- and spatial transcriptomics, as well as in vitro and in vivo live-cell imaging to define supratentorial ependymoma cell states, spatial organization, and dynamic behavior within the neural microenvironment. We find that individual tumor subgroups harbor two distinct progenitor-like cell states reminiscent of early human brain development and diverge in the extent of neuronal or ependymal differentiation. We further uncover several modes of spatial organization of these tumors, including a high order architecture influenced by mesenchymal and hypoxia signatures. Finally, we identify an unappreciated role for brain-resident cells in shifting supratentorial ependymoma cellular heterogeneity towards neuronal-like cells that co-opt immature neuronal morphology and invasion mechanisms. Collectively, these findings provide a multidimensional framework to integrate transcriptional and phenotypic characterization of tumor heterogeneity in supratentorial ependymoma and its potential clinical implications.

cancer biology↗

bioRxiv2023

Single cell transcriptomic profiling identifies tumor-acquired and therapy-resistant cell states in pediatric rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is a pediatric tumor that resembles undifferentiated muscle cells; yet the extent to which cell state heterogeneity and molecular features are shared with human development have not been fully ascribed. Here, we report a single-cell/nucleus RNA sequencing atlas derived from 72 datasets that includes patient tumors, patient-derived xenografts, primary in vitro cultures, and established cell lines. We report four dominant muscle-lineage cell states in RMS: progenitors, proliferative, differentiated, and ground cells. We stratify these RMS cells along the continuum of human muscle development and show that RMS cells share expression patterns with fetal/embryonal myogenic precursors rather than postnatal satellite cells. Indeed, fusion-negative RMS (FN-RMS) have a discrete stem cell hierarchy that faithfully recapitulates fetal muscle development. We also identify therapy-resistant FN-RMS progenitor cells that share transcriptomic similarity with bipotent skeletal mesenchymal cells, while a subset of fusion-positive (FP) RMS have tumor-acquired cells states, including a neuronal cell state, that are not found in development. Chemotherapy induced upregulation of progenitor signatures in FN-RMS while the neuronal gene programs were retained after therapy in FP-RMS. Taken together, this work identifies new cell state heterogeneity including unique treatment-resistant and tumor-acquired cell states that differ across RMS subtypes.

cancer biology↗

bioRxiv2022

Single-cell mapping of tumor heterogeneity in pediatric rhabdomyosarcoma reveals developmental signatures with therapeutic relevance

Rhabdomyosarcoma (RMS) is an aggressive human pediatric cancer. Despite robust expression of myogenic regulatory factors, RMS cells are blocked in a proliferative state and do not terminally differentiate. The extent to which the skeletal muscle lineage is represented in RMS tumors and the mechanisms leading to developmental arrest remain elusive. Here, we combined single-cell RNA sequencing (scRNAseq), mass cytometry (CyTOF) and high-content imaging to resolve RMS heterogeneity. ScRNAseq and CyTOF analysis of a total of 17 patient-derived primary cultures and three cell lines uncovered plastic myogenic subpopulations that delineate a branched trajectory. The less aggressive embryonal RMS (eRMS) harbor primarily muscle stem cell (MuSC)-like cells and exhibit sparse commitment to differentiation. The more aggressive alveolar RMS (aRMS) comprise primarily actively cycling committed progenitors with a paucity of differentiated cells. The oncogenic fusion protein PAX3:FOXO1 sustains aRMS cells in the cycling trajectory loop, which we show can re-wired towards differentiation upon its downregulation or by dual pharmacological RAF and MEK inhibition. Our findings provide insights into the developmental states and trajectories underlying RMS progression and identify the RAS pathway as a promising target of differentiation therapy for human aRMS. STATEMENT OF SIGNIFICANCEWe present the first comprehensive single-cell transcriptomic and proteomic atlas of pediatric rhabdomyosarcoma (RMS), in which we identify impaired myogenic trajectories with prognostic value. We demonstrate that RAS pathway inhibitors disrupt the oncogenic trajectory and induce terminal differentiation, revealing novel therapeutic targets for the aggressive alveolar RMS subtype.

cancer biology↗