A single-cell/nucleus atlas of pediatric rhabdomyosarcoma
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ABSTRACT: Rhabdomyosarcoma (RMS) is the most soft tissue sarcoma of childhood and histologically mimics developing skeletal muscle. To better understand RMS, we performed single-cell RNA-seq of one embryonal subtype RMS (ERMS) and one alveolar subtype RMS (ARMS). We expanded our observations by performing single-nucleus RNA-seq of 18 patient tumors (12 ERMS, 6 ARMS). All 18 of these tumors were used to generate orthotopic patient-derived xenografts, and we performed single-cell RNA-seq of all 18 O-PDXs to compare heterogeneity between the original tumor and the patient-derived model. 15 of the O-PDXs underwent lentiviral barcoding, and lineage could be tracked using a separate dial-out PCR step during the single-cell RNA-seq workflow. We performed single-cell RNA-seq of an ex vivo organoid, showing that we can preserve heterogeneity in this model. We expanded our study to the epigenetic level by using single-cell ATAC-sequencing of 7 O-PDXs. Finally, we longitudinally tracked shifts in heterogeneity in an O-PDX model treated with chemotherapy.
Project description:To elucidate the pathogenesis of rhabdomyosarcoma (RMS), particularly for different subgroups, we performed a SNP array-based copy number analysis of 46 RMS specimens from primary cases with ERMS (N = 21), ARMS (N = 14), unclassified RMS (N = 1), and RMS of unknown histology (N = 3) together with 7 RMS-derived cell lines. The ERMS subtype was characterized by hyperploidy and was significantly associated with gains of chromosomes 2, 8, and 12, whereas majority of ARMS cases exhibited near-diploid copy number profiles. Recurrent loss of heterozygosity (LOH) of chromosomes 3 (28.6%) and 15q (35.7%) was detected in ARMS. Uniparental disomy/polysomy of 11p was commonly found in both tumor types. Focal gains/amplifications were associated mostly with PAX3-FOXO1 (5/10) or PAX7-FOXO1 (6/6) fusions, but novel amplified regions were also found, including the IRS2 in 2 ARMS. Gain of 13q was significantly associated with good patient outcome in ERMS. These findings not only illustrate genetic differences between ARMS and ERMS but also provide novel insights into the pathogenesis of RMS. Copy number analysis of Affymetrix 50K/250K SNP arrays was performed for 46 RMS samples.
Project description:To elucidate the pathogenesis of rhabdomyosarcoma (RMS), particularly for different subgroups, we performed a SNP array-based copy number analysis of 54 RMS specimens from primary cases with ERMS (N = 30), ARMS (N = 14), unclassified RMS (N = 1), and RMS of unknown histology (N = 3) together with 7 RMS-derived cell lines. The ERMS subtype was characterized by hyperploidy and was significantly associated with gains of chromosomes 2, 8, and 12, whereas majority of ARMS cases exhibited near-diploid copy number profiles. Recurrent loss of heterozygosity (LOH) of chromosomes 3 (28.6%) and 15q (35.7%) was detected in ARMS. Uniparental disomy/polysomy of 11p was commonly found in both tumor types. Focal gains/amplifications were associated mostly with PAX3-FOXO1 (5/10) or PAX7-FOXO1 (6/6) fusions, but novel amplified regions were also found, including the IRS2 in 2 ARMS. Gain of 13q was significantly associated with good patient outcome in ERMS. These findings not only illustrate genetic differences between ARMS and ERMS but also provide novel insights into the pathogenesis of RMS.
Project description:Frozen skeletal muscle, tumor adjacent skeletal muscle, Endothelial Rhabdomyosarcoma (ERMS) and Alveolar Rhabdomyosarcoma (ARMS) samples were profiled on Illumina bead array. Total RNA from primary resected samples were profiled to allow comparison of 1) normal skeletal muscle tissue with RMS samples and 2) ARMS with ERMS tumors.
Project description:Exosomes were isolated by differential centrifugation from the fusion negative human embryonal rhabdomyosarcoma (ERMS) cell lines (JR1, Rh36, and RD) and fusion positive alveolar RMS (ARMS) cell lines (Rh30 and Rh41) and characterized by western blot for exosomal markers. miRNA content of the RMS-derived exosomes was determined using the Affymetrix GeneChip miRNA 3.0 array and analyzed to specify differentially deregulated (either enriched or depleted) miRNA relative to cellular miRNA from the respective ERMS and ARMS cell lines. Characterization of the miRNA content of RMS exosome is needed to better understand the mechanism by which these particles exert their physiologic effects, notably on proliferation, migration, invasion, and metastasis.
Project description:This SuperSeries is composed of the SubSeries listed below. Background: Rhabdomyosarcomas (RMS) are rare but very aggressive tumors of childhood that arise as a consequence of regulatory distruption of the growth and differentiation pathways of myogenic precursor cells. Based on morphology, two major RMS subtypes can be identified: embryonal RMS (ERMS) and alveolar (ARMS). So, it is essential to unravel the molecular mechanisms involved in cancer pathogenesis and in disease progression. MicroRNAs are endogenous small non-coding RNAs with a key role in tumorigenesis. Methodology/Principal Findings: To better understand the involvement of miRNAs in RMS, we analyzed the expression profile of 8 different RMS cell lines (4 ARMS and 4 ERMS). The miRNA population from each cell line was compared to a reference sample consisting of a pool of each total RNA sample mixed in equal amount. We identified a 16 miRNAs signature that discriminates translocation positive (ARMS) and negative RMS (ERMS). We focused our attention on the role of miR-27a that is up-regulated in the more aggressive RMS cell lines (ARMS translocation positive) where probably it acts as an oncogene. miR-27a-overexpressing cells showed a significant enhance of the proliferation rate, paralleled by a decrease of cells in G1 phase. We demonstrated that miR-27a is implicated in cell cycle control by targeting the retinoic acid alpha receptor (RARA) and retinoic X receptor alpha (RXRA). Conclusions: Our results demonstrated the potential of miRNA expression signature to better classify different RMS subtypes and settled the basis for a potential therapeutic role of miR-27a in RMS through modulation of retinoic acid receptors expression.
Project description:In this study, we interrogated the protein composition of exosomes purified from cell culture supernatants of 5 different RMS cell lines, by LC-MS/MS technology and analysis using bio-informatics tools. We attempted to characterize the differences and similarities between exosomes derived from ERMS and ARMS cells, and common as well as unique characteristics of RMS exosome protein content when compared to that of other cancer and non-cancer cells. Our results identify potential protein exosome biomarkers for RMS to be further investigated in future clinical studies.
Project description:Circular RNAs (circRNAs) represent a class of covalently closed RNAs, derived from a non-canonical splicing event, ubiquitously expressed among Eukaryotes and conserved among different species. We identified a circRNA (circ-ZNF609) involved in the regulation of human primary myoblast proliferation. Upon its depletion, the percentage of proliferating myoblasts was highly reduced. To deepen our knowledge about circ-ZNF609 role in cell cycle regulation, we studied its expression and function in Rhabdomyosarcoma (RMS), a pediatric skeletal muscle malignancy. We found that circ-ZNF609 is up-regulated in biopsies from both the two major RMS subtypes, the alveolar (ARMS) and the embryonal (ERMS), and we discovered that its knock-down blocks proliferation of an ERMS-derived cell line, while it has no effect on ARMS-derived cells. To understand the mechanism through which circ-ZNF609 affects cell proliferation we compared the different effects of circ-ZNF609 depletion in ERMS and ARMS and we identified genes and pathways on which the circRNA acts.
Project description:The Hippo pathway effector YAP1 controls stem cell fate in epithelial tissues, but its role in stem cells of non-epithelial tissues, such as skeletal muscle, is poorly documented. Here we show that sustained YAP1 activity in mouse activated satellite cells in vivo induces rhabdomyosarcoma (RMS) resembling human embryonal RMS (ERMS) with high penetrance and short latency. The transcriptional program of YAP1 in ERMS drives pro-proliferative pathways whilst decreasing MyoD1 and MEF2 pro-differentiation activity to globally maintain the myoblastic phenotype of ERMS. Normalization of YAP1 expression reduced tumor burden and allowed myogenic differentiation of YAP1-driven and RD ERMS xenografts in situ, thereby identifying YAP1 as a potent RMS-causing oncogene and potential target for differentiation therapy. A total of four samples were analyzed. Two ChIP-Seq datasets from RD human cells, containing reads connected to TEAD binding and IgG binding as control/background; two ChIP-Seq datasets from YAP-ERMS mouse cells, containing reads connected to TEAD binding and Input reads as control/background
Project description:Rhabdomyosarcoma (RMS) is a highly malignant tumour accounting for nearly half of soft tissue sarcomas in children. Altered miRNA levels have been reported in human cancers, including RMS. Using deep sequencing technology, a total of 685 miRNAs were investigated in a group of alveolar RMSs (ARMSs), embryonal RMSs (ERMSs) as well as in normal skeletal muscle (NSM). Bioinformatics pipelines were used for miRNA target prediction and clustering analysis. Ninety-seven miRNAs were significantly deregulated in ARMS and ERMS when compared to NSM. MiR-378 family members were dramatically decreased in RMS tumour tissue and cell lines. Interestingly, members of the miR-378 family presented as a possible target the insulin-like growth factor receptor 1 (IGF1R), a key signalling molecule in RMS.
Project description:Rhabdomyosarcomas (RMS) represent a family of aggressive soft tissue sarcomas that present in both the pediatric and adult setting. Pathologic risk stratification for RMS has been based on histologic subtype, with poor outcomes observed in alveolar rhabdomyosarcoma (ARMS) and adult-type pleomorphic rhabdomyosarcoma (PRMS) compared to embryonal rhabdomyosarcoma (ERMS). Recent genomic sequencing studies have expanded the spectrum of RMS, with several new molecularly defined entities, including fusion-driven spindle cell/sclerosing rhabdomyosarcoma (SC/SRMS) and MYOD1-mutant SC/SRMS. Comprehensive genomic analysis has previously defined the mutational and copy number spectrum for the more common ERMS and ARMS, as well as revealed corresponding methylation signatures. In contrast, genetic and epigenetic correlates have not been defined for the rare SC/SRMS or PRMS histologic subtypes. Herein, we present genomic sequencing, copy number analysis, and methylation profiling of the largest cohort of molecularly characterized RMS samples to date. We identified two novel methylation subtypes, one having SC/SRMS histology and defined by MYOD1 p. L122R mutations and the other matching adult type PRMS. Selected tumors from adolescent patients grouped with the PRMS methylation class, expanding the age range of these rare tumors. Pediatric patients in the MYOD1-mutant group, as well as those clustering with PRMS, appear to have poor overall survival.