Publications by authors named "Jo Lynne Rokita"

17 Publications

  • Page 1 of 1

Macrophages in SHH subgroup medulloblastoma display dynamic heterogeneity that varies with treatment modality.

Cell Rep 2021 Mar;34(13):108917

Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Electronic address:

Tumor-associated macrophages (TAMs) play an important role in tumor immunity and comprise of subsets that have distinct phenotype, function, and ontology. Transcriptomic analyses of human medulloblastoma, the most common malignant pediatric brain cancer, showed that medulloblastomas (MBs) with activated sonic hedgehog signaling (SHH-MB) have significantly more TAMs than other MB subtypes. Therefore, we examined MB-associated TAMs by single-cell RNA sequencing of autochthonous murine SHH-MB at steady state and under two distinct treatment modalities: molecular-targeted inhibitor and radiation. Our analyses reveal significant TAM heterogeneity, identify markers of ontologically distinct TAM subsets, and show the impact of brain microenvironment on the differentiation of tumor-infiltrating monocytes. TAM composition undergoes dramatic changes with treatment and differs significantly between molecular-targeted and radiation therapy. We identify an immunosuppressive monocyte-derived TAM subset that emerges with radiation therapy and demonstrate its role in regulating T cell and neutrophil infiltration in MB.
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http://dx.doi.org/10.1016/j.celrep.2021.108917DOI Listing
March 2021

GAS7 Deficiency Promotes Metastasis in MYCN-driven Neuroblastoma.

Cancer Res 2021 Feb 18. Epub 2021 Feb 18.

Department of Biochemistry and Molecular Biology, Mayo Clinic

One of the greatest barriers to curative treatment of neuroblastoma (NB) is its frequent metastatic outgrowth prior to diagnosis, especially in cases driven by amplification of the MYCN oncogene. However, only a limited number of regulatory proteins that contribute to this complex MYCN-mediated process have been elucidated. Here we show that the growth arrest-specific 7 (GAS7) gene, located at chromosome band 17p13.1, is preferentially deleted in high-risk MYCN-driven NB. GAS7 expression was also suppressed in MYCN-amplified NB lacking 17p deletion. GAS7 deficiency led to accelerated metastasis in both zebrafish and mammalian models of NB with overexpression or amplification of MYCN. Analysis of expression profiles and the ultrastructure of zebrafish NB tumors with MYCN overexpression identified that GAS7 deficiency led to (i) downregulation of genes involved in cell-cell interaction, (ii) loss of contact among tumor cells as critical determinants of accelerated metastasis, and (iii) increased levels of MYCN protein. These results provide the first genetic evidence that GAS7 depletion is a critical early step in the cascade of events culminating in NB metastasis in the context of MYCN overexpression.
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http://dx.doi.org/10.1158/0008-5472.CAN-20-1890DOI Listing
February 2021

annoFuse: an R Package to annotate, prioritize, and interactively explore putative oncogenic RNA fusions.

BMC Bioinformatics 2020 Dec 14;21(1):577. Epub 2020 Dec 14.

Center for Data-Driven Discovery in Biomedicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA.

Background: Gene fusion events are significant sources of somatic variation across adult and pediatric cancers and are some of the most clinically-effective therapeutic targets, yet low consensus of RNA-Seq fusion prediction algorithms makes therapeutic prioritization difficult. In addition, events such as polymerase read-throughs, mis-mapping due to gene homology, and fusions occurring in healthy normal tissue require informed filtering, making it difficult for researchers and clinicians to rapidly discern gene fusions that might be true underlying oncogenic drivers of a tumor and in some cases, appropriate targets for therapy.

Results: We developed annoFuse, an R package, and shinyFuse, a companion web application, to annotate, prioritize, and explore biologically-relevant expressed gene fusions, downstream of fusion calling. We validated annoFuse using a random cohort of TCGA RNA-Seq samples (N = 160) and achieved a 96% sensitivity for retention of high-confidence fusions (N = 603). annoFuse uses FusionAnnotator annotations to filter non-oncogenic and/or artifactual fusions. Then, fusions are prioritized if previously reported in TCGA and/or fusions containing gene partners that are known oncogenes, tumor suppressor genes, COSMIC genes, and/or transcription factors. We applied annoFuse to fusion calls from pediatric brain tumor RNA-Seq samples (N = 1028) provided as part of the Open Pediatric Brain Tumor Atlas (OpenPBTA) Project to determine recurrent fusions and recurrently-fused genes within different brain tumor histologies. annoFuse annotates protein domains using the PFAM database, assesses reciprocality, and annotates gene partners for kinase domain retention. As a standard function, reportFuse enables generation of a reproducible R Markdown report to summarize filtered fusions, visualize breakpoints and protein domains by transcript, and plot recurrent fusions within cohorts. Finally, we created shinyFuse for algorithm-agnostic interactive exploration and plotting of gene fusions.

Conclusions: annoFuse provides standardized filtering and annotation for gene fusion calls from STAR-Fusion and Arriba by merging, filtering, and prioritizing putative oncogenic fusions across large cancer datasets, as demonstrated here with data from the OpenPBTA project. We are expanding the package to be widely-applicable to other fusion algorithms and expect annoFuse to provide researchers a method for rapidly evaluating, prioritizing, and translating fusion findings in patient tumors.
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http://dx.doi.org/10.1186/s12859-020-03922-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7737294PMC
December 2020

Integrated Proteogenomic Characterization across Major Histological Types of Pediatric Brain Cancer.

Cell 2020 Dec 25;183(7):1962-1985.e31. Epub 2020 Nov 25.

Department of Genetics and Genomic Sciences and Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Electronic address:

We report a comprehensive proteogenomics analysis, including whole-genome sequencing, RNA sequencing, and proteomics and phosphoproteomics profiling, of 218 tumors across 7 histological types of childhood brain cancer: low-grade glioma (n = 93), ependymoma (32), high-grade glioma (25), medulloblastoma (22), ganglioglioma (18), craniopharyngioma (16), and atypical teratoid rhabdoid tumor (12). Proteomics data identify common biological themes that span histological boundaries, suggesting that treatments used for one histological type may be applied effectively to other tumors sharing similar proteomics features. Immune landscape characterization reveals diverse tumor microenvironments across and within diagnoses. Proteomics data further reveal functional effects of somatic mutations and copy number variations (CNVs) not evident in transcriptomics data. Kinase-substrate association and co-expression network analysis identify important biological mechanisms of tumorigenesis. This is the first large-scale proteogenomics analysis across traditional histological boundaries to uncover foundational pediatric brain tumor biology and inform rational treatment selection.
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http://dx.doi.org/10.1016/j.cell.2020.10.044DOI Listing
December 2020

A transcriptome-based classifier to determine molecular subtypes in medulloblastoma.

PLoS Comput Biol 2020 10 29;16(10):e1008263. Epub 2020 Oct 29.

Center for Data-Driven Discovery in Biomedicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America.

Medulloblastoma is a highly heterogeneous pediatric brain tumor with five molecular subtypes, Sonic Hedgehog TP53-mutant, Sonic Hedgehog TP53-wildtype, WNT, Group 3, and Group 4, defined by the World Health Organization. The current mechanism for classification into these molecular subtypes is through the use of immunostaining, methylation, and/or genetics. We surveyed the literature and identified a number of RNA-Seq and microarray datasets in order to develop, train, test, and validate a robust classifier to identify medulloblastoma molecular subtypes through the use of transcriptomic profiling data. We have developed a GPL-3 licensed R package and a Shiny Application to enable users to quickly and robustly classify medulloblastoma samples using transcriptomic data. The classifier utilizes a large composite microarray dataset (15 individual datasets), an individual microarray study, and an RNA-Seq dataset, using gene ratios instead of gene expression measures as features for the model. Discriminating features were identified using the limma R package and samples were classified using an unweighted mean of normalized scores. We utilized two training datasets and applied the classifier in 15 separate datasets. We observed a minimum accuracy of 85.71% in the smallest dataset and a maximum of 100% accuracy in four datasets with an overall median accuracy of 97.8% across the 15 datasets, with the majority of misclassification occurring between the heterogeneous Group 3 and Group 4 subtypes. We anticipate this medulloblastoma transcriptomic subtype classifier will be broadly applicable to the cancer research and clinical communities.
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http://dx.doi.org/10.1371/journal.pcbi.1008263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7654754PMC
October 2020

LIN28B promotes neuroblastoma metastasis and regulates PDZ binding kinase.

Neoplasia 2020 Apr 24;22(6):231-241. Epub 2020 Apr 24.

Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Children's Healthcare of Atlanta, Atlanta, GA 30322, USA; Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA. Electronic address:

Neuroblastoma is an aggressive pediatric malignancy of the neural crest with suboptimal cure rates and a striking predilection for widespread metastases, underscoring the need to identify novel therapeutic vulnerabilities. We recently identified the RNA binding protein LIN28B as a driver in high-risk neuroblastoma and demonstrated it promotes oncogenic cell proliferation by coordinating a RAN-Aurora kinase A network. Here, we demonstrate that LIN28B influences another key hallmark of cancer, metastatic dissemination. Using a murine xenograft model of neuroblastoma dissemination, we show that LIN28B promotes metastasis. We demonstrate that this is in part due to the effects of LIN28B on self-renewal and migration, providing an understanding of how LIN28B shapes the metastatic phenotype. Our studies reveal that the let-7 family, which LIN28B inhibits, decreases self-renewal and migration. Next, we identify PDZ Binding Kinase (PBK) as a novel LIN28B target. PBK is a serine/threonine kinase that promotes the proliferation and self-renewal of neural stem cells and serves as an oncogenic driver in multiple aggressive malignancies. We demonstrate that PBK is both a novel direct target of let-7i and that MYCN regulates PBK expression, thus elucidating two oncogenic drivers that converge on PBK. Functionally, PBK promotes self-renewal and migration, phenocopying LIN28B. Taken together, our findings define a role for LIN28B in neuroblastoma metastasis and define the targetable kinase PBK as a potential novel vulnerability in metastatic neuroblastoma.
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http://dx.doi.org/10.1016/j.neo.2020.04.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7186370PMC
April 2020

Limited antitumor activity of combined BET and MEK inhibition in neuroblastoma.

Pediatr Blood Cancer 2020 06 19;67(6):e28267. Epub 2020 Apr 19.

Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta and Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia.

Background: The treatment of high-risk neuroblastoma continues to present a formidable challenge to pediatric oncology. Previous studies have shown that Bromodomain and extraterminal (BET) inhibitors can inhibit MYCN expression and suppress MYCN-amplified neuroblastoma in vivo. Furthermore, alterations within RAS-MAPK (mitogen-activated protein kinase) signaling play significant roles in neuroblastoma initiation, maintenance, and relapse, and mitogen-activated extracellular signal-regulated kinase (MEK) inhibitors demonstrate efficacy in subsets of neuroblastoma preclinical models. Finally, hyperactivation of RAS-MAPK signaling has been shown to promote resistance to BET inhibitors. Therefore, we examined the antitumor efficacy of combined BET/MEK inhibition utilizing I-BET726 or I-BET762 and trametinib in high-risk neuroblastoma.

Procedure: Utilizing a panel of genomically annotated neuroblastoma cell line models, we investigated the in vitro effects of combined BET/MEK inhibition on cell proliferation and apoptosis. Furthermore, we evaluated the effects of combined inhibition in neuroblastoma xenograft models.

Results: Combined BET and MEK inhibition demonstrated synergistic effects on the growth and survival of a large panel of neuroblastoma cell lines through augmentation of apoptosis. A combination therapy slowed tumor growth in a non-MYCN-amplified, NRAS-mutated neuroblastoma xenograft model, but had no efficacy in an MYCN-amplified model harboring a loss-of-function mutation in NF1.

Conclusions: Combinatorial BET and MEK inhibition was synergistic in the vast majority of neuroblastoma cell lines in the in vitro setting but showed limited antitumor activity in vivo. Collectively, these data do not support clinical development of this combination in high-risk neuroblastoma.
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http://dx.doi.org/10.1002/pbc.28267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7188563PMC
June 2020

Telomere Maintenance Mechanisms Define Clinical Outcome in High-Risk Neuroblastoma.

Cancer Res 2020 06 14;80(12):2663-2675. Epub 2020 Apr 14.

Cancer Center and Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center School of Medicine, Texas.

Neuroblastoma is a childhood cancer with heterogeneous clinical outcomes. To comprehensively assess the impact of telomere maintenance mechanism (TMM) on clinical outcomes in high-risk neuroblastoma, we integrated the C-circle assay [a marker for alternative lengthening of telomeres (ALT)], TERT mRNA expression by RNA-sequencing, whole-genome/exome sequencing, and clinical covariates in 134 neuroblastoma patient samples at diagnosis. In addition, we assessed TMM in neuroblastoma cell lines ( = 104) and patient-derived xenografts ( = 28). ALT was identified in 23.4% of high-risk neuroblastoma tumors and genomic alterations in were detected in 60% of ALT tumors; 40% of ALT tumors lacked genomic alterations in known ALT-associated genes. Patients with high-risk neuroblastoma were classified into three subgroups (TERT-high, ALT, and TERT-low/non-ALT) based on presence of C-circles and TERT mRNA expression (above or below median TERT expression). Event-free survival was similar among TERT-high, ALT, or TERT-low/non-ALT patients. However, overall survival (OS) for TERT-low/non-ALT patients was significantly higher relative to TERT-high or ALT patients (log-rank test; < 0.01) independent of current clinical and molecular prognostic markers. Consistent with the observed higher OS in patients with TERT-low/non-ALT tumors, continuous shortening of telomeres and decreasing viability occurred in low TERT-expressing, non-ALT patient-derived high-risk neuroblastoma cell lines. These findings demonstrate that assaying TMM with TERT mRNA expression and C-circles provides precise stratification of high-risk neuroblastoma into three subgroups with substantially different OS: a previously undescribed TERT-low/non-ALT cohort with superior OS (even after relapse) and two cohorts of patients with poor survival that have distinct molecular therapeutic targets. SIGNIFICANCE: These findings assess telomere maintenance mechanisms with TERT mRNA and the ALT DNA biomarker C-circles to stratify neuroblastoma into three groups, with distinct overall survival independent of currently used clinical risk classifiers.
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http://dx.doi.org/10.1158/0008-5472.CAN-19-3068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7313726PMC
June 2020

Epigenomic profiling of neuroblastoma cell lines.

Sci Data 2020 04 14;7(1):116. Epub 2020 Apr 14.

Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, 19104, USA.

Understanding the aberrant transcriptional landscape of neuroblastoma is necessary to provide insight to the underlying influences of the initiation, progression and persistence of this developmental cancer. Here, we present chromatin immunoprecipitation sequencing (ChIP-Seq) data for the oncogenic transcription factors, MYCN and MYC, as well as regulatory histone marks H3K4me1, H3K4me3, H3K27Ac, and H3K27me3 in ten commonly used human neuroblastoma-derived cell line models. In addition, for all of the profiled cell lines we provide ATAC-Seq as a measure of open chromatin. We validate specificity of global MYCN occupancy in MYCN amplified cell lines and functional redundancy of MYC occupancy in MYCN non-amplified cell lines. Finally, we show with H3K27Ac ChIP-Seq that these cell lines retain expression of key neuroblastoma super-enhancers (SE). We anticipate this dataset, coupled with available transcriptomic profiling on the same cell lines, will enable the discovery of novel gene regulatory mechanisms in neuroblastoma.
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http://dx.doi.org/10.1038/s41597-020-0458-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7156688PMC
April 2020

CAMKV Is a Candidate Immunotherapeutic Target in Amplified Neuroblastoma.

Front Oncol 2020 6;10:302. Epub 2020 Mar 6.

Division of Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA, United States.

We developed a computational pipeline designed to use RNA sequencing ( = 136) and gene expression profiling ( = 250) data from neuroblastoma tumors to identify cell surface proteins predicted to be highly expressed in amplified neuroblastomas and with little or no expression in normal human tissues. We then performed ChIP-seq in the amplified cell lines KELLY, NB-1643, and NGP to identify gene promoters that are occupied by MYCN protein to define the intersection with the differentially-expressed gene list. We initially identified 116 putative immunotherapy targets with predicted transmembrane domains, with the most significant differentially-expressed of these being the calmodulin kinase-like vesicle-associated gene (CAMKV, = 2 × 10). CAMKV encodes a protein that binds calmodulin in the presence of calcium, but lacks the kinase activity of other calmodulin kinase family members. We confirmed that CAMKV is selectively expressed in 7/7 amplified neuroblastoma cell lines and showed that the transcription of is directly controlled by MYCN. From membrane fractionation and immunohistochemistry, we verified that CAMKV is membranous in amplified neuroblastoma cell lines and patient-derived xenografts. Finally, immunohistochemistry showed that CAMKV is not expressed on normal tissues outside of the central nervous system. Together, these data demonstrate that CAMKV is a differentially-expressed cell surface protein that is transcriptionally regulated by MYCN, making it a candidate for targeting with antibodies or antibody-drug conjugates that do not cross the blood brain barrier.
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http://dx.doi.org/10.3389/fonc.2020.00302DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7069022PMC
March 2020

ASCL1 is a MYCN- and LMO1-dependent member of the adrenergic neuroblastoma core regulatory circuitry.

Nat Commun 2019 12 9;10(1):5622. Epub 2019 Dec 9.

Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore.

A heritable polymorphism within regulatory sequences of the LMO1 gene is associated with its elevated expression and increased susceptibility to develop neuroblastoma, but the oncogenic pathways downstream of the LMO1 transcriptional co-regulatory protein are unknown. Our ChIP-seq and RNA-seq analyses reveal that a key gene directly regulated by LMO1 and MYCN is ASCL1, which encodes a basic helix-loop-helix transcription factor. Regulatory elements controlling ASCL1 expression are bound by LMO1, MYCN and the transcription factors GATA3, HAND2, PHOX2B, TBX2 and ISL1-all members of the adrenergic (ADRN) neuroblastoma core regulatory circuitry (CRC). ASCL1 is required for neuroblastoma cell growth and arrest of differentiation. ASCL1 and LMO1 directly regulate the expression of CRC genes, indicating that ASCL1 is a member and LMO1 is a coregulator of the ADRN neuroblastoma CRC.
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http://dx.doi.org/10.1038/s41467-019-13515-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6901540PMC
December 2019

Combined innate and adaptive immunotherapy overcomes resistance of immunologically cold syngeneic murine neuroblastoma to checkpoint inhibition.

J Immunother Cancer 2019 12 6;7(1):344. Epub 2019 Dec 6.

Department of Pediatrics, University of Wisconsin, 4159 WIMR Bldg., UWCCC, 1111 Highland Ave, Madison, WI, 53711, USA.

Background: Unlike some adult cancers, most pediatric cancers are considered immunologically cold and generally less responsive to immunotherapy. While immunotherapy has already been incorporated into standard of care treatment for pediatric patients with high-risk neuroblastoma, overall survival remains poor. In a mouse melanoma model, we found that radiation and tumor-specific immunocytokine generate an in situ vaccination response in syngeneic mice bearing large tumors. Here, we tested whether a novel immunotherapeutic approach utilizing radiation and immunocytokine together with innate immune stimulation could generate a potent antitumor response with immunologic memory against syngeneic murine neuroblastoma.

Methods: Mice bearing disialoganglioside (GD2)-expressing neuroblastoma tumors (either NXS2 or 9464D-GD2) were treated with radiation and immunotherapy (including anti-GD2 immunocytokine with or without anti-CTLA-4, CpG and anti-CD40 monoclonal antibody). Tumor growth, animal survival and immune cell infiltrate were analyzed in the tumor microenvironment in response to various treatment regimens.

Results: NXS2 had a moderate tumor mutation burden (TMB) while N-MYC driven 9464D-GD2 had a low TMB, therefore the latter served as a better model for high-risk neuroblastoma (an immunologically cold tumor). Radiation and immunocytokine induced a potent in situ vaccination response against NXS2 tumors, but not in the 9464D-GD2 tumor model. Addition of checkpoint blockade with anti-CTLA-4 was not effective alone against 9464D-GD2 tumors; inclusion of CpG and anti-CD40 achieved a potent antitumor response with decreased T regulatory cells within the tumors and induction of immunologic memory.

Conclusions: These data suggest that a combined innate and adaptive immunotherapeutic approach can be effective against immunologically cold syngeneic murine neuroblastoma. Further testing is needed to determine how these concepts might translate into development of more effective immunotherapeutic approaches for the treatment of clinically high-risk neuroblastoma.
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http://dx.doi.org/10.1186/s40425-019-0823-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6898936PMC
December 2019

Genomic Profiling of Childhood Tumor Patient-Derived Xenograft Models to Enable Rational Clinical Trial Design.

Cell Rep 2019 11;29(6):1675-1689.e9

Division of Oncology, Children's Hospital of Philadelphia, and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-4318, USA. Electronic address:

Accelerating cures for children with cancer remains an immediate challenge as a result of extensive oncogenic heterogeneity between and within histologies, distinct molecular mechanisms evolving between diagnosis and relapsed disease, and limited therapeutic options. To systematically prioritize and rationally test novel agents in preclinical murine models, researchers within the Pediatric Preclinical Testing Consortium are continuously developing patient-derived xenografts (PDXs)-many of which are refractory to current standard-of-care treatments-from high-risk childhood cancers. Here, we genomically characterize 261 PDX models from 37 unique pediatric cancers; demonstrate faithful recapitulation of histologies and subtypes; and refine our understanding of relapsed disease. In addition, we use expression signatures to classify tumors for TP53 and NF1 pathway inactivation. We anticipate that these data will serve as a resource for pediatric oncology drug development and will guide rational clinical trial design for children with cancer.
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http://dx.doi.org/10.1016/j.celrep.2019.09.071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6880934PMC
November 2019

YAP1 Mediates Resistance to MEK1/2 Inhibition in Neuroblastomas with Hyperactivated RAS Signaling.

Cancer Res 2019 12 31;79(24):6204-6214. Epub 2019 Oct 31.

Division of Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.

Relapsed neuroblastomas are enriched with activating mutations of the RAS-MAPK signaling pathway. The MEK1/2 inhibitor trametinib delays tumor growth but does not sustain regression in neuroblastoma preclinical models. Recent studies have implicated the Hippo pathway transcriptional coactivator protein YAP1 as an additional driver of relapsed neuroblastomas, as well as a mediator of trametinib resistance in other cancers. Here, we used a highly annotated set of high-risk neuroblastoma cellular models to modulate YAP1 expression and RAS pathway activation to test whether increased YAP1 transcriptional activity is a mechanism of MEK1/2 inhibition resistance in RAS-driven neuroblastomas. In NLF (biallelic NF1 inactivation) and SK-N-AS (NRAS Q61K) cell lines, trametinib caused a near-complete translocation of YAP1 protein into the nucleus. YAP1 depletion sensitized neuroblastoma cells to trametinib, while overexpression of constitutively active YAP1 protein induced trametinib resistance. Mechanistically, significant enhancement of G-S cell-cycle arrest, mediated by depletion of MYC/MYCN and E2F transcriptional output, sensitized RAS-driven neuroblastomas to trametinib following YAP1 deletion. These findings underscore the importance of YAP activity in response to trametinib in RAS-driven neuroblastomas, as well as the potential for targeting YAP in a trametinib combination. SIGNIFICANCE: High-risk neuroblastomas with hyperactivated RAS signaling escape the selective pressure of MEK inhibition via YAP1-mediated transcriptional reprogramming and may be sensitive to combination therapies targeting both YAP1 and MEK.
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http://dx.doi.org/10.1158/0008-5472.CAN-19-1415DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6911631PMC
December 2019

Germline 16p11.2 Microdeletion Predisposes to Neuroblastoma.

Am J Hum Genet 2019 09 29;105(3):658-668. Epub 2019 Aug 29.

Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Oncology, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Genomics and Computational Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address:

Neuroblastoma is a cancer of the developing sympathetic nervous system. It is diagnosed in 600-700 children per year in the United States and accounts for 12% of pediatric cancer deaths. Despite recent advances in our understanding of this malignancy's complex genetic architecture, the contribution of rare germline variants remains undefined. Here, we conducted a genome-wide analysis of large (>500 kb), rare (<1%) germline copy number variants (CNVs) in two independent, multi-ethnic cohorts totaling 5,585 children with neuroblastoma and 23,505 cancer-free control children. We identified a 550-kb deletion on chromosome 16p11.2 significantly enriched in neuroblastoma cases (0.39% of cases and 0.03% of controls; p = 3.34 × 10). Notably, this CNV corresponds to a known microdeletion syndrome that affects approximately one in 3,000 children and confers risk for diverse developmental phenotypes including autism spectrum disorder and other neurodevelopmental disorders. The CNV had a substantial impact on neuroblastoma risk, with an odds ratio of 13.9 (95% confidence interval = 5.8-33.4). The association remained significant when we restricted our analysis to individuals of European ancestry in order to mitigate potential confounding by population stratification (0.42% of cases and 0.03% of controls; p = 4.10 × 10). We used whole-genome sequencing (WGS) to validate the deletion in paired germline and tumor DNA from 12 cases. Finally, WGS of four parent-child trios revealed that the deletion primarily arose de novo without maternal or paternal bias. This finding expands the clinical phenotypes associated with 16p11.2 microdeletion syndrome to include cancer, and it suggests that disruption of the 16p11.2 region may dysregulate neurodevelopmental pathways that influence both neurological phenotypes and neuroblastoma.
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http://dx.doi.org/10.1016/j.ajhg.2019.07.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6731370PMC
September 2019

The Pediatric Cell Atlas: Defining the Growth Phase of Human Development at Single-Cell Resolution.

Dev Cell 2019 04 28;49(1):10-29. Epub 2019 Mar 28.

Department of Biomedical Informatics, University of Cincinnati College of Medicine, and Cincinnati Children's Hospital Medical Center, Division of Biomedical Informatics, Cincinnati, OH 45229, USA.

Single-cell gene expression analyses of mammalian tissues have uncovered profound stage-specific molecular regulatory phenomena that have changed the understanding of unique cell types and signaling pathways critical for lineage determination, morphogenesis, and growth. We discuss here the case for a Pediatric Cell Atlas as part of the Human Cell Atlas consortium to provide single-cell profiles and spatial characterization of gene expression across human tissues and organs. Such data will complement adult and developmentally focused HCA projects to provide a rich cytogenomic framework for understanding not only pediatric health and disease but also environmental and genetic impacts across the human lifespan.
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http://dx.doi.org/10.1016/j.devcel.2019.03.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6616346PMC
April 2019