EHD1 is Required for IGF-1R-mediated Oncogenic Signaling in Ewing Sarcoma

Background and Significance: Ewing Sarcoma (EWS) is the second most common malignant bone tumor of children and adolescents. Patients with metastatic or recurrent disease have very poor outcomes. The receptor tyrosine kinase(RTK) insulin-like-growth-factor-1-receptor (IGF-1R) is upregulated in 93% of EWS patients with anti-IGF-1R antibodies and kinase inhibitors in clinical studies. However, with only ~10% of patients achieving objective responses, delineation of novel pathways that facilitate IGF-1R-driven oncogenesis in EWS could provide avenues for more effective therapy. The RTK levels and compartmentalization at the cell surface determine their access to growth factors, thus dictating the downstream oncogenic signaling. Our lab has demonstrated that EPS15-homology-domain-containing-protein-1 (EHD1) regulates traffic of cell surface receptors, including RTKs. We observed high frequency (67%) of EHD1 overexpression in 266 primary EWS patient tumor tissues, and Kaplan-Meier survival analysis of publicly available mRNA expression data showed that high EHD1 expression was associated with shorter patient survival. Objective/Question: This study aims to comprehend the underlying role of EHD1 in EWS oncogenesis. Experimental design and Results: In both dox-inducible EHD1-shRNA knockdown and EHD1-CRISPR-Cas9-knockout (KO) EWS cell line models(TC71, A673, and SKES1), we observed a significant impairment of in vitro oncogenic properties namely, cell proliferation, migration, invasion, soft-agar colony formation, and tumor-sphere formation, and the phenotypes were restored upon mouse-EHD1 rescue. Furthermore, by orthotopically implanting TC71 cells in the tibia of nude mice(xenograft model), we demonstrated a significant reduction in tumor size upon EHD1-depletion. Using a phospho-RTK profiling antibody array, we found reduced phospho-IGF-1R levels upon EHD1-KD, identifying IGF-1R as a potential target of regulation by EHD1. EHD1-KO reduced surface IGF-1R levels under steady-state and ligand-free conditions in EWS cells. IGF-1R and EHD1 were also found to colocalize intracellularly and co-immunoprecipitate after IGF-1 stimulation. Notably, EHD1-KO impaired the IGF-1R-mediated activation of downstream AKT and MAPK pathways. Mechanistically, EHD1 was shown to regulate traffic of newly synthesized IGF-1R and recycled pools from the Golgi to the cell surface, and in absence of EHD1, intracellular IGF-1R was shunted to the lysosome resulting in degradation. Finally, by dual targeting of EHD1 (genetic depletion) and IGF-1R (small-molecule-inhibitor Linsitinib), we observed an additive effect on inhibition of EWS cell proliferation and migration and upregulation of apoptosis. Conclusions: Our studies indicate a novel regulatory pathway of EHD1 requirement in IGF-1R cell surface display and sustaining IGF-1R-mediated oncogenesis in EWS. This highlights the prospects of therapeutic co-targeting of EHD1 and IGF-1R, thus enhancing IGF-1R targeted therapies in EWS.https://digitalcommons.unmc.edu/chri_forum/1040/thumbnail.jp

GALC Deletions Increase the Risk of Primary Open-Angle Glaucoma: The Role of Mendelian Variants in Complex Disease

DNA copy number variants (CNVs) have been reported in many human diseases including autism and schizophrenia. Primary Open Angle Glaucoma (POAG) is a complex adult-onset disorder characterized by progressive optic neuropathy and vision loss. Previous studies have identified rare CNVs in POAG; however, their low frequencies prevented formal association testing. We present here the association between POAG risk and a heterozygous deletion in the galactosylceramidase gene (GALC). This CNV was initially identified in a dataset containing 71 Caucasian POAG cases and 478 ethnically matched controls obtained from dbGAP (study accession phs000126.v1.p1.) (p = 0.017, fisher's exact test). It was validated with array comparative genomic hybridization (arrayCGH) and realtime PCR, and replicated in an independent POAG dataset containing 959 cases and 1852 controls (p = 0.021, OR (odds ratio) = 3.5, 95% CI −1.1–12.0). Evidence for association was strengthened when the discovery and replication datasets were combined (p = 0.002; OR = 5.0, 95% CI 1.6–16.4). Several deletions with different endpoints were identified by array CGH of POAG patients. Homozygous deletions that eliminate GALC enzymatic activity cause Krabbe disease, a recessive Mendelian disorder of childhood displaying bilateral optic neuropathy and vision loss. Our findings suggest that heterozygous deletions that reduce GALC activity are a novel mechanism increasing risk of POAG. This is the first report of a statistically-significant association of a CNV with POAG risk, contributing to a growing body of evidence that CNVs play an important role in complex, inherited disorders. Our findings suggest an attractive biomarker and potential therapeutic target for patients with this form of POAG

How can chiropractic become a respected mainstream profession? The example of podiatry

<p>Abstract</p> <p>Background</p> <p>The chiropractic profession has succeeded to remain in existence for over 110 years despite the fact that many other professions which had their start at around the same time as chiropractic have disappeared. Despite chiropractic's longevity, the profession has not succeeded in establishing cultural authority and respect within mainstream society, and its market share is dwindling. In the meantime, the podiatric medical profession, during approximately the same time period, has been far more successful in developing itself into a respected profession that is well integrated into mainstream health care and society.</p> <p>Objective</p> <p>To present a perspective on the current state of the chiropractic profession and to make recommendations as to how the profession can look to the podiatric medical profession as a model for how a non-allopathic healthcare profession can establish mainstream integration and cultural authority.</p> <p>Discussion</p> <p>There are several key areas in which the podiatric medical profession has succeeded and in which the chiropractic profession has not. The authors contend that it is in these key areas that changes must be made in order for our profession to overcome its shrinking market share and its present low status amongst healthcare professions. These areas include public health, education, identity and professionalism.</p> <p>Conclusion</p> <p>The chiropractic profession has great promise in terms of its potential contribution to society and the potential for its members to realize the benefits that come from being involved in a mainstream, respected and highly utilized professional group. However, there are several changes that must be made within the profession if it is going to fulfill this promise. Several lessons can be learned from the podiatric medical profession in this effort.</p

Schizophrenia-associated somatic copy-number variants from 12,834 cases reveal recurrent NRXN1 and ABCB11 disruptions

While germline copy-number variants (CNVs) contribute to schizophrenia (SCZ) risk, the contribution of somatic CNVs (sCNVs)—present in some but not all cells—remains unknown. We identified sCNVs using blood-derived genotype arrays from 12,834 SCZ cases and 11,648 controls, filtering sCNVs at loci recurrently mutated in clonal blood disorders. Likely early-developmental sCNVs were more common in cases (0.91%) than controls (0.51%, p = 2.68e−4), with recurrent somatic deletions of exons 1–5 of the NRXN1 gene in five SCZ cases. Hi-C maps revealed ectopic, allele-specific loops forming between a potential cryptic promoter and non-coding cis-regulatory elements upon 5′ deletions in NRXN1. We also observed recurrent intragenic deletions of ABCB11, encoding a transporter implicated in anti-psychotic response, in five treatment-resistant SCZ cases and showed that ABCB11 is specifically enriched in neurons forming mesocortical and mesolimbic dopaminergic projections. Our results indicate potential roles of sCNVs in SCZ risk

Impact of miRNA-mRNA Profiling and Their Correlation on Medulloblastoma Tumorigenesis

Medulloblastoma (MB) is a clinically challenging, childhood brain tumor with a diverse genetic makeup and differential miRNA profile. Aiming to identify deregulated miRNAs in MB, the miRNA expression profile of human MB samples was compared to that of normal cerebellar tissues. As a result, 8 upregulated and 64 downregulated miRNAs were identified in MB samples. Although various algorithms have been developed to predict the interaction between miRNA-mRNA pairs, the complexity and fidelity of miRNA-mRNA remain a concern. Therefore, to identify the signatures of miRNA-mRNA interactions essential for MB pathogenesis, miRNA profiling, RNA sequencing, and ingenuity pathway analysis (IPA) were performed in the same primary human MB samples. Further, when miR-217 was inhibited, a significant upregulation of predicted target genes SIRT1, ROBO1, FOXO3, and SMAD7 in HDMB03 cells was observed, confirming the validity of our approach. Functional analysis revealed that the inhibition of miR-217 in HDMB03 cells suppresses colony formation, migration, invasion, promoted apoptosis, and arrested cell population in S phase, indicating that manipulation of miR-217 may have a therapeutic potential for MB patients. Therefore, our study provides an essential platform for future investigations of specific miRNAs responsible for MB pathogenesis. Keywords: medulloblastoma, miRNA profiling, RNA-seq, miRNA-mRNA correlation, miR-21

EHD1-dependent traffic of IGF-1 receptor to the cell surface is essential for Ewing sarcoma tumorigenesis and metastasis

Abstract Overexpression of the EPS15 Homology Domain containing 1 (EHD1) protein has been linked to tumorigenesis but whether its core function as a regulator of intracellular traffic of cell surface receptors plays a role in oncogenesis remains unknown. We establish that EHD1 is overexpressed in Ewing sarcoma (EWS), with high EHD1 mRNA expression specifying shorter patient survival. ShRNA-knockdown and CRISPR-knockout with mouse Ehd1 rescue established a requirement of EHD1 for tumorigenesis and metastasis. RTK antibody arrays identified IGF-1R as a target of EHD1 regulation in EWS. Mechanistically, we demonstrate a requirement of EHD1 for endocytic recycling and Golgi to plasma membrane traffic of IGF-1R to maintain its surface expression and downstream signaling. Conversely, EHD1 overexpression-dependent exaggerated oncogenic traits require IGF-1R expression and kinase activity. Our findings define the RTK traffic regulation as a proximal mechanism of EHD1 overexpression-dependent oncogenesis that impinges on IGF-1R in EWS, supporting the potential of IGF-1R and EHD1 co-targeting