Publications by authors named "David A Largaespada"

164 Publications

WNT5A inhibition alters the malignant peripheral nerve sheath tumor microenvironment and enhances tumor growth.

Oncogene 2021 Jun 2;40(24):4229-4241. Epub 2021 Jun 2.

Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.

Malignant peripheral nerve sheath tumors (MPNST) are aggressive soft-tissue sarcomas that cause significant mortality in adults with neurofibromatosis type 1. We compared gene expression of growth factors in normal human nerves to MPNST and normal human Schwann cells to MPNST cell lines. We identified WNT5A as the most significantly upregulated ligand-coding gene and verified its protein expression in MPNST cell lines and tumors. In many contexts WNT5A acts as an oncogene. However, inhibiting WNT5A expression using shRNA did not alter MPNST cell proliferation, invasion, migration, or survival in vitro. Rather, shWNT5A-treated MPNST cells upregulated mRNAs associated with the remodeling of extracellular matrix and with immune cell communication. In addition, these cells secreted increased amounts of the proinflammatory cytokines CXCL1, CCL2, IL6, CXCL8, and ICAM1. Versus controls, shWNT5A-expressing MPNST cells formed larger tumors in vivo. Grafted tumors contained elevated macrophage/stromal cells, larger and more numerous blood vessels, and increased levels of Mmp9, Cxcl13, Lipocalin-1, and Ccl12. In some MPNST settings, these effects were mimicked by targeting the WNT5A receptor ROR2. These data suggest that the non-canonical Wnt ligand WNT5A inhibits MPNST tumor formation by modulating the MPNST microenvironment, so that blocking WNT5A accelerates tumor growth in vivo.
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http://dx.doi.org/10.1038/s41388-021-01773-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8217297PMC
June 2021

Selumetinib normalizes Ras/MAPK signaling in clinically relevant neurofibromatosis type 1 minipig tissues in vivo.

Neurooncol Adv 2021 Jan-Dec;3(1):vdab020. Epub 2021 Feb 10.

Recombinetics Inc., Eagan, Minnesota, USA.

Background: The MEK1/2 inhibitor selumetinib was recently approved for neurofibromatosis type 1 (NF1)-associated plexiform neurofibromas, but outcomes could be improved and its pharmacodynamic evaluation in other relevant tissues is limited. The aim of this study was to assess selumetinib tissue pharmacokinetics (PK) and pharmacodynamics (PD) using a minipig model of NF1.

Methods: WT ( = 8) and NF1 ( = 8) minipigs received a single oral dose of 7.3 mg/kg selumetinib. Peripheral blood mononuclear cells (PBMCs), cerebral cortex, optic nerve, sciatic nerve, and skin were collected for PK analysis and PD analysis of extracellular regulated kinase phosphorylation (p-ERK) inhibition and transcript biomarkers ( & ).

Results: Key selumetinib PK parameters aligned with those observed in human patients. Selumetinib concentrations were higher in CNS tissues from NF1 compared to WT animals. Inhibition of ERK phosphorylation was achieved in PBMCs (mean 60% reduction), skin (95%), and sciatic nerve (64%) from all minipigs, whereas inhibition of ERK phosphorylation in cerebral cortex was detected only in NF1 animals (71%). Basal p-ERK levels were significantly higher in NF1 minipig optic nerve compared to WT and were reduced to WT levels (60%) with selumetinib. Modulation of transcript biomarkers was observed in all tissues.

Conclusions: Selumetinib reduces MAPK signaling in tissues clinically relevant to NF1, effectively normalizing p-ERK to WT levels in optic nerve but resulting in abnormally low levels of p-ERK in the skin. These results suggest that selumetinib exerts activity in NF1-associated CNS tumors by normalizing Ras/MAPK signaling and may explain common MEK inhibitor-associated dermatologic toxicities.
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http://dx.doi.org/10.1093/noajnl/vdab020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8095338PMC
February 2021

Reversing Imatinib's Immunosuppressive Effects by Modulating Type I IFN Signaling.

Cancer Immunol Res 2021 May;9(5):489

Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota.

Signal pathway inhibition is a well-validated approach for treating cancers driven by activated kinases such as KIT. However, kinase inhibitors may make tumor cells less responsive to tumor immune surveillance and less sensitive to immunotherapies. In this issue, Liu and colleagues report that, in a mouse model, inhibition of oncogenic KIT in gastrointestinal stromal tumors reduces type I interferon (IFN) production and signaling, and the effectiveness of the immune system in controlling tumor growth. They were able to partially overcome the immunosuppressive effects of KIT inhibition using agonists of the type I IFN response, pointing the way toward intelligently combining kinase inhibitors and immune modulators for therapy..
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http://dx.doi.org/10.1158/2326-6066.CIR-21-0177DOI Listing
May 2021

Transposon Mutagenesis-Guided CRISPR/Cas9 Screening Strongly Implicates Dysregulation of Hippo/YAP Signaling in Malignant Peripheral Nerve Sheath Tumor Development.

Cancers (Basel) 2021 Mar 30;13(7). Epub 2021 Mar 30.

Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive, genomically complex, have soft tissue sarcomas, and are derived from the Schwann cell lineage. Patients with neurofibromatosis type 1 syndrome (NF1), an autosomal dominant tumor predisposition syndrome, are at a high risk for MPNSTs, which usually develop from pre-existing benign Schwann cell tumors called plexiform neurofibromas. NF1 is characterized by loss-of-function mutations in the gene, which encode neurofibromin, a Ras GTPase activating protein (GAP) and negative regulator of RasGTP-dependent signaling. In addition to bi-allelic loss of , other known tumor suppressor genes include , , , and , all of which are often inactivated in the process of MPNST growth. A sleeping beauty (SB) transposon-based genetic screen for high-grade Schwann cell tumors in mice, and comparative genomics, implicated Wnt/β-catenin, PI3K-AKT-mTOR, and other pathways in MPNST development and progression. We endeavored to more systematically test genes and pathways implicated by our screen in mice, i.e., in a human immortalized Schwann cell-based model and a human MPNST cell line, using CRISPR/Cas9 technology. We individually induced loss-of-function mutations in 103 tumor suppressor genes (TSG) and oncogene candidates. We assessed anchorage-independent growth, transwell migration, and for a subset of genes, tumor formation in vivo. When tested in a loss-of-function fashion, about 60% of all TSG candidates resulted in the transformation of immortalized human Schwann cells, whereas 30% of oncogene candidates resulted in growth arrest in a MPNST cell line. Individual loss-of-function mutations in the , , , and genes resulted in transformation of immortalized human Schwann cells and tumor formation in a xenograft model. Moreover, the loss of all four of these genes resulted in activation of Hippo/Yes Activated Protein (YAP) signaling. By combining transposon mutagenesis and CRISPR/Cas9 screening, we established a useful pipeline for the validation of MPNST pathways and genes. Our results suggest that the functional genetic landscape of human MPNST is complex and implicate the Hippo/YAP pathway in the transformation of neurofibromas. It is thus imperative to functionally validate individual cancer genes and pathways using human cell-based models, to determinate their role in different stages of MPNST development, growth, and/or metastasis.
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http://dx.doi.org/10.3390/cancers13071584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8038069PMC
March 2021

Neurofibromatosis in the Era of Precision Medicine: Development of MEK Inhibitors and Recent Successes with Selumetinib.

Curr Oncol Rep 2021 Mar 15;23(4):45. Epub 2021 Mar 15.

Division of Pediatric Hematology & Oncology, University of Minnesota, Minneapolis, MN, USA.

Purpose Of Review: Patients with neurofibromatosis type 1 (NF1) are at increased risk for benign and malignant neoplasms. Recently, targeted therapy with the MEK inhibitor class has helped address these needs. We highlight recent successes with selumetinib while acknowledging ongoing challenges for NF1 patients and future directions.

Recent Findings: MEK inhibitors have demonstrated efficacy for NF1-related conditions, including plexiform neurofibromas and low-grade gliomas, two common causes of NF1-related morbidity. Active investigations for NF1-related neoplasms have benefited from advanced understanding of the genomic and cell signaling alterations in these conditions and development of sound preclinical animal models. Selumetinib has become the first FDA-approved targeted therapy for NF1 following its demonstrated efficacy for inoperable plexiform neurofibroma. Investigations of combination therapy and the development of a representative NF1 swine model hold promise for translating therapies for other NF1-associated pathology.
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http://dx.doi.org/10.1007/s11912-021-01032-yDOI Listing
March 2021

Spontaneous and Engineered Large Animal Models of Neurofibromatosis Type 1.

Int J Mol Sci 2021 Feb 16;22(4). Epub 2021 Feb 16.

Masonic Cancer Center, Department of Pediatrics, Division of Hematology and Oncology, University of Minnesota, Minneapolis, MN 55455, USA.

Animal models are crucial to understanding human disease biology and developing new therapies. By far the most common animal used to investigate prevailing questions about human disease is the mouse. Mouse models are powerful tools for research as their small size, limited lifespan, and defined genetic background allow researchers to easily manipulate their genome and maintain large numbers of animals in general laboratory spaces. However, it is precisely these attributes that make them so different from humans and explains, in part, why these models do not accurately predict drug responses in human patients. This is particularly true of the neurofibromatoses (NFs), a group of genetic diseases that predispose individuals to tumors of the nervous system, the most common of which is Neurofibromatosis type 1 (NF1). Despite years of research, there are still many unanswered questions and few effective treatments for NF1. Genetically engineered mice have drastically improved our understanding of many aspects of NF1, but they do not exemplify the overall complexity of the disease and some findings do not translate well to humans due to differences in body size and physiology. Moreover, NF1 mouse models are heavily reliant on the Cre-Lox system, which does not accurately reflect the molecular mechanism of spontaneous loss of heterozygosity that accompanies human tumor development. Spontaneous and genetically engineered large animal models may provide a valuable supplement to rodent studies for NF1. Naturally occurring comparative models of disease are an attractive prospect because they occur on heterogeneous genetic backgrounds and are due to spontaneous rather than engineered mutations. The use of animals with naturally occurring disease has been effective for studying osteosarcoma, lymphoma, and diabetes. Spontaneous NF-like symptoms including neurofibromas and malignant peripheral nerve sheath tumors (MPNST) have been documented in several large animal species and share biological and clinical similarities with human NF1. These animals could provide additional insight into the complex biology of NF1 and potentially provide a platform for pre-clinical trials. Additionally, genetically engineered porcine models of NF1 have recently been developed and display a variety of clinical features similar to those seen in NF1 patients. Their large size and relatively long lifespan allow for longitudinal imaging studies and evaluation of innovative surgical techniques using human equipment. Greater genetic, anatomic, and physiologic similarities to humans enable the engineering of precise disease alleles found in human patients and make them ideal for preclinical pharmacokinetic and pharmacodynamic studies of small molecule, cellular, and gene therapies prior to clinical trials in patients. Comparative genomic studies between humans and animals with naturally occurring disease, as well as preclinical studies in large animal disease models, may help identify new targets for therapeutic intervention and expedite the translation of new therapies. In this review, we discuss new genetically engineered large animal models of NF1 and cases of spontaneous NF-like manifestations in large animals, with a special emphasis on how these comparative models could act as a crucial translational intermediary between specialized murine models and NF1 patients.
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http://dx.doi.org/10.3390/ijms22041954DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7920315PMC
February 2021

Flow Assisted Mutation Enrichment (FAME): A highly efficacious and efficient method to enrich Double Knockouts (DKO) after gene editing.

PLoS One 2021 4;16(3):e0247375. Epub 2021 Mar 4.

Division of Endocrinology, Phoenix VA Medical Center, Phoenix, Arizona, United States of America.

Gene editing has become an essential tool for interrogation of gene function in biomedical research and is also a promising approach for gene therapy. Despite recent progresses, the gene-editing procedure is still a tedious process involving manually isolating large number of single cell colonies to screen for desired mutations. For diploid eukaryotic cells, there is the additional challenge to inactivate both alleles for genes-of-interest, i.e., generating double knockouts (DKOs), for the desired phenotypes or therapeutic effects. In this report, we present a novel method based on Fluorescence Assisted Cell Sorting (FACS) to enrich for DKO cells, using a cell surface marker β2-microglobulin (B2M) as a basis for negative selection. This method significantly increased percentage of DKOs in isolated cells after gene editing, and in the meantime, significantly improve the efficiency of workflow by automating colony isolation. It would greatly facilitate future biomedical research including potential gene/cell therapies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247375PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7932066PMC
March 2021

ZBTB20 regulates WNT/CTNNB1 signalling pathway by suppressing PPARG during hepatocellular carcinoma tumourigenesis.

JHEP Rep 2021 Apr 19;3(2):100223. Epub 2020 Dec 19.

Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR.

Background & Aims: Zinc finger and BTB domain containing 20 () has been implicated as a potential oncogene in liver cancer. However, knockout studies have shown it to be a transcriptional repressor of the alpha-foetoprotein () gene in adult liver, and reduced levels of allow for upregulation of with increased tumour severity in certain cases of hepatocellular carcinoma (HCC). As there are many discrepancies in the literature regarding its role in liver tumourigenesis, the aim of this study was to elucidate the role of in HCC tumourigenesis.

Methods: A reverse genetic study using the Sleeping Beauty () transposon system in mice was performed to elucidate the role of in HCC tumourigenesis. gain- and loss-of-function experiments were used to assess the relationship amongst ZBTB20, peroxisome proliferator activated receptor gamma (PPARG) and catenin beta 1 (CTNNB1).

Results: Transgenic overexpression of in hepatocytes and in the context of transformation related protein ( ) inactivation induced hepatic hypertrophy, activation of WNT/CTNNB1 signalling, and development of liver tumours. overexpression and knockout experiments using CRISPR/Cas9 demonstrated the important role for ZBTB20 in downregulating PPARG, resulting in activation of the WNT/CTNNB1 signalling pathway and its downstream effectors in HCC tumourigenesis.

Conclusions: These findings demonstrate a novel interaction between ZBTB20 and PPARG, which leads to activation of the WNT/CTNNB1 signalling pathway in HCC tumourigenesis.

Lay Summary: has been implicated as a potential oncogene in liver cancer. Herein, we uncover its important role in liver cancer development. We show that it interacts with PPARG to upregulate the WNT/CTNNB1 signalling pathway, leading to tumourigenesis.
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http://dx.doi.org/10.1016/j.jhepr.2020.100223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7873381PMC
April 2021

Sex differences in expression of immune elements emerge in children, young adults and mice with osteosarcoma.

Biol Sex Differ 2021 01 6;12(1). Epub 2021 Jan 6.

Department of Pediatrics, University of Minnesota School of Medicine, Minneapolis, MN, USA.

Background: Males < 40 years old are more likely to be diagnosed with and die from osteosarcoma (OS). The underlying mechanisms may depend on sex differences in immune response.

Methods: We used SEER data to estimate survival differences between males and females aged < 40 years at OS diagnosis. In NCI TARGET-OS cases, we determined sex differences in gene expression, conducted Gene Set Enrichment Analysis (GSEA), and applied the LM22 signature to identify biologic sex differences. We compared sex differences in gene expression profiles in TARGET-OS to those observed in Sleeping Beauty (SB) transposon mutagenesis accelerated Trp53-mutant mouse-OS and healthy adult osteoblasts.

Results: Males had worse 17-year overall survival than females (SEER p < 0.0001). From 87 TARGET-OS cases, we observed 1018 genes and 69 pathways that differed significantly by sex (adjusted p < 0.05). Pathway and gene lists overlapped with those from mice (p = 0.03) and healthy osteoblasts (p = 0.017), respectively. Pathways that differed significantly by sex were largely immune-based and included the PD-1/PD-L1 immunotherapy pathway. We observed sex differences in M2 macrophages (LM22; p = 0.056) and M1-M2 macrophage transition (GSEA; p = 0.037) in TARGET-OS. LM22 trends were similar in mice. Twenty-four genes differentially expressed by sex in TARGET-OS had existing cancer therapies.

Conclusions: Sex differences in OS gene expression were similar across species and centered on immune pathways. Identified sex-specific therapeutic targets may improve outcomes in young individuals with OS.
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http://dx.doi.org/10.1186/s13293-020-00347-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7789366PMC
January 2021

R-Spondins 2 and 3 Are Overexpressed in a Subset of Human Colon and Breast Cancers.

DNA Cell Biol 2021 Jan 15;40(1):70-79. Epub 2020 Dec 15.

Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, USA.

Wnt signaling is activated in many cancer types, yet targeting the canonical Wnt pathway has been challenging for cancer therapy. The pathway might be effectively targeted at many levels depending on the mechanism by which it has become hyperactive. Recently, mouse genetic screens have found that R-spondins (RSPOs) act as oncogenes. Evidence includes recurrent genomic rearrangements that led to increased or expression in human colorectal adenocarcinomas, exclusive of mutations. RSPOs modulate Wnt signaling to promote epithelial cell proliferation and survival. These secreted proteins modulate Wnt signaling by binding to G-coupled receptors LGR4/5/6, ultimately inhibiting frizzled membrane clearance by RNF43 and ZNRF3. They also exert their function independent of leucine-rich repeat-containing, G protein-coupled receptors (LGRs) by binding to ZNRF3 and RNF43. This results in increased β-catenin concentration that, after translocation to the nucleus, acts as a transcriptional coactivator of genes necessary for proliferation and cell survival. In this article, we aimed to identify the role of in colon and breast cancers by using and studies. We found that expression of and at high levels characterized a subset of colorectal cancers (CRCs). expression was found to characterize a subset of triple-negative breast cancers. In both instances, increased expression of was associated with an activated Wnt signaling gene expression profile. Furthermore, knockdown of decreased Wnt signaling and proliferation in human breast cancer cells. Our findings show and confirm that and expression is upregulated in a subset of colorectal adenocarcinomas and breast cancers and that both are attractive druggable oncoprotein targets against such cancers. We also describe novel fusion transcripts that occur in CRC.
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http://dx.doi.org/10.1089/dna.2020.5585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821429PMC
January 2021

Implication of in Accelerating Tumor Development and Therapeutically Targeting ZNF217-Induced PI3K-AKT Signaling for the Treatment of Metastatic Osteosarcoma.

Mol Cancer Ther 2020 12 30;19(12):2528-2541. Epub 2020 Sep 30.

Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.

We previously identified as an oncogenic driver of a subset of osteosarcomas using the () transposon system. Here, we followed up by investigating the genetic role of in osteosarcoma initiation and progression through the establishment of a novel genetically engineered mouse model, assays, orthotopic mouse studies, and paired these findings with preclinical studies using a small-molecule inhibitor. Throughout, we demonstrate that ZNF217 is coupled to numerous facets of osteosarcoma transformation, including proliferation, cell motility, and anchorage independent growth, and ultimately promoting osteosarcoma growth, progression, and metastasis in part through positive modulation of PI3K-AKT survival signaling. Pharmacologic blockade of AKT signaling with nucleoside analogue triciribine in ZNF217 orthotopically injected osteosarcoma cell lines reduced tumor growth and metastasis. Our data demonstrate that triciribine treatment may be a relevant and efficacious therapeutic strategy for patients with osteosarcoma with ZNF217 and p-AKT rich tumors. With the recent revitalization of triciribine for clinical studies in other solid cancers, our study provides a rationale for further evaluation preclinically with the purpose of clinical evaluation in patients with incurable, ZNF217 osteosarcoma.
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http://dx.doi.org/10.1158/1535-7163.MCT-20-0369DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8290861PMC
December 2020

APOBEC3A catalyzes mutation and drives carcinogenesis in vivo.

J Exp Med 2020 12;217(12)

Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN.

The APOBEC3 family of antiviral DNA cytosine deaminases is implicated as the second largest source of mutation in cancer. This mutational process may be a causal driver or inconsequential passenger to the overall tumor phenotype. We show that human APOBEC3A expression in murine colon and liver tissues increases tumorigenesis. All other APOBEC3 family members, including APOBEC3B, fail to promote liver tumor formation. Tumor DNA sequences from APOBEC3A-expressing animals display hallmark APOBEC signature mutations in TCA/T motifs. Bioinformatic comparisons of the observed APOBEC3A mutation signature in murine tumors, previously reported APOBEC3A and APOBEC3B mutation signatures in yeast, and reanalyzed APOBEC mutation signatures in human tumor datasets support cause-and-effect relationships for APOBEC3A-catalyzed deamination and mutagenesis in driving multiple human cancers.
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http://dx.doi.org/10.1084/jem.20200261DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953736PMC
December 2020

Loss in a Model of Neurofibroma Demonstrates Stepwise Tumor Progression to Atypical Neurofibroma and MPNST.

Cancer Res 2020 11 19;80(21):4720-4730. Epub 2020 Aug 19.

Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio.

Plexiform neurofibromas are benign nerve sheath Schwann cell tumors characterized by biallelic mutations in the neurofibromatosis type 1 (NF1) tumor suppressor gene. Atypical neurofibromas show additional frequent loss of CDKN2A/Ink4a/Arf and may be precursor lesions of aggressive malignant peripheral nerve sheath tumors (MPNST). Here we combined loss of Nf1 in developing Schwann cells with global Ink4a/Arf loss and identified paraspinal plexiform neurofibromas and atypical neurofibromas. Upon transplantation, atypical neurofibromas generated genetically engineered mice (GEM)-PNST similar to human MPNST, and tumors showed reduced p16INK4a protein and reduced senescence markers, confirming susceptibility to transformation. Superficial GEM-PNST contained regions of nerve-associated plexiform neurofibromas or atypical neurofibromas and grew rapidly on transplantation. Transcriptome analyses showed similarities to corresponding human tumors. Thus, we recapitulated nerve tumor progression in NF1 and provided preclinical platforms for testing therapies at each tumor grade. These results support a tumor progression model in which loss of NF1 in Schwann cells drives plexiform neurofibromas formation, additional loss of Ink4a/Arf contributes to atypical neurofibromas formation, and further changes underlie transformation to MPNST. SIGNIFICANCE: New mouse models recapitulate the stepwise progression of NF1 tumors and will be useful to define effective treatments that halt tumor growth and tumor progression in NF1.
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http://dx.doi.org/10.1158/0008-5472.CAN-19-1429DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7968129PMC
November 2020

Overexpression of HGF/MET axis along with p53 inhibition induces de novo glioma formation in mice.

Neurooncol Adv 2020 Jan-Dec;2(1):vdaa067. Epub 2020 Jun 4.

Department of Biomedical Science, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA.

Background: Aberrant MET receptor tyrosine kinase (RTK) activation leads to invasive tumor growth in different types of cancer. Overexpression of MET and its ligand hepatocyte growth factor (HGF) occurs more frequently in glioblastoma (GBM) than in low-grade gliomas. Although we have shown previously that HGF-autocrine activation predicts sensitivity to MET tyrosine kinase inhibitors (TKIs) in GBM, whether it initiates tumorigenesis remains elusive.

Methods: Using a well-established Sleeping Beauty (SB) transposon strategy, we injected human and cDNA together with a short hairpin siRNA against (SB-hHgf.Met.ShP53) into the lateral ventricle of neonatal mice to induce spontaneous glioma initiation and characterized the tumors with H&E and immunohistochemistry analysis. Glioma sphere cells also were isolated for measuring the sensitivity to specific MET TKIs.

Results: Mixed injection of SB-hHgf.Met.ShP53 plasmids induced de novo glioma formation with invasive tumor growth accompanied by HGF and MET overexpression. While glioma stem cells (GSCs) are considered as the tumor-initiating cells in GBM, both SB-hHgf.Met.ShP53 tumor sections and glioma spheres harvested from these tumors expressed GSC markers nestin, GFAP, and Sox 2. Moreover, specific MET TKIs significantly inhibited tumor spheres' proliferation and MET/MAPK/AKT signaling.

Conclusions: Overexpression of the HGF/MET axis along with p53 attenuation may transform neural stem cells into GSCs, resulting in GBM formation in mice. These tumors are primarily driven by the MET RTK pathway activation and are sensitive to MET TKIs. The SB-hHgf.Met.ShP53 spontaneous mouse glioma model provides a useful tool for studying GBM tumor biology and MET-targeting therapeutics.
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http://dx.doi.org/10.1093/noajnl/vdaa067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7332240PMC
June 2020

New Model Systems and the Development of Targeted Therapies for the Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors.

Genes (Basel) 2020 04 28;11(5). Epub 2020 Apr 28.

Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA.

Neurofibromatosis Type 1 (NF1) is a common genetic disorder and cancer predisposition syndrome (1:3000 births) caused by mutations in the tumor suppressor gene . encodes neurofibromin, a negative regulator of the Ras signaling pathway. Individuals with NF1 often develop benign tumors of the peripheral nervous system (neurofibromas), originating from the Schwann cell linage, some of which progress further to malignant peripheral nerve sheath tumors (MPNSTs). Treatment options for neurofibromas and MPNSTs are extremely limited, relying largely on surgical resection and cytotoxic chemotherapy. Identification of novel therapeutic targets in both benign neurofibromas and MPNSTs is critical for improved patient outcomes and quality of life. Recent clinical trials conducted in patients with NF1 for the treatment of symptomatic plexiform neurofibromas using inhibitors of the mitogen-activated protein kinase (MEK) have shown very promising results. However, MEK inhibitors do not work in all patients and have significant side effects. In addition, preliminary evidence suggests single agent use of MEK inhibitors for MPNST treatment will fail. Here, we describe the preclinical efforts that led to the identification of MEK inhibitors as promising therapeutics for the treatment of NF1-related neoplasia and possible reasons they lack single agent efficacy in the treatment of MPNSTs. In addition, we describe work to find targets other than MEK for treatment of MPNST. These have come from studies of RAS biochemistry, in vitro drug screening, forward genetic screens for Schwann cell tumors, and synthetic lethal screens in cells with oncogenic gene mutations. Lastly, we discuss new approaches to exploit drug screening and synthetic lethality with loss of function mutations in human Schwann cells using CRISPR/Cas9 technology.
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http://dx.doi.org/10.3390/genes11050477DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290716PMC
April 2020

PLX3397 treatment inhibits constitutive CSF1R-induced oncogenic ERK signaling, reduces tumor growth, and metastatic burden in osteosarcoma.

Bone 2020 07 3;136:115353. Epub 2020 Apr 3.

Department of Pediatrics, University of Minnesota, United States of America; Department of Genetics, Cell Biology and Development, University of Minnesota, United States of America; Center for Genome Engineering, University of Minnesota, United States of America; Masonic Cancer Center, University of Minnesota, United States of America. Electronic address:

Osteosarcoma (OSA) is a heterogeneous and aggressive solid tumor of the bone. We recently identified the colony stimulating factor 1 receptor (Csf1r) gene as a novel driver of osteosarcomagenesis in mice using the Sleeping Beauty (SB) transposon mutagenesis system. Here, we report that a CSF1R-CSF1 autocrine/paracrine signaling mechanism is constitutively activated in a subset of human OSA cases and is critical for promoting tumor growth and contributes to metastasis. We examined CSF1R and CSF1 expression in OSAs. We utilized gain-of-function and loss-of-function studies (GOF/LOF) to evaluate properties of cellular transformation, downstream signaling, and mechanisms of CSF1R-CSF1 action. Genetic perturbation of CSF1R in immortalized osteoblasts and human OSA cell lines significantly altered oncogenic properties, which were dependent on the CSF1R-CSF1 autocrine/paracrine signaling. These functional alterations were associated with changes in the known CSF1R downstream ERK effector pathway and mitotic cell cycle arrest. We evaluated the recently FDA-approved CSF1R inhibitor Pexidartinib (PLX3397) in OSA cell lines in vitro and in vivo in cell line and patient-derived xenografts. Pharmacological inhibition of CSF1R signaling recapitulated the in vitro genetic alterations. Moreover, in orthotopic OSA cell line and subcutaneous patient-derived xenograft (PDX)-injected mouse models, PLX3397 treatment significantly inhibited local OSA tumor growth and lessened metastatic burden. In summary, CSF1R is utilized by OSA cells to promote tumorigenesis and may represent a new molecular target for therapy.
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http://dx.doi.org/10.1016/j.bone.2020.115353DOI Listing
July 2020

Transposon Insertion Mutagenesis in Mice for Modeling Human Cancers: Critical Insights Gained and New Opportunities.

Int J Mol Sci 2020 Feb 10;21(3). Epub 2020 Feb 10.

Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA.

Transposon mutagenesis has been used to model many types of human cancer in mice, leading to the discovery of novel cancer genes and insights into the mechanism of tumorigenesis. For this review, we identified over twenty types of human cancer that have been modeled in the mouse using and transposon insertion mutagenesis. We examine several specific biological insights that have been gained and describe opportunities for continued research. Specifically, we review studies with a focus on understanding metastasis, therapy resistance, and tumor cell of origin. Additionally, we propose further uses of transposon-based models to identify rarely mutated driver genes across many cancers, understand additional mechanisms of drug resistance and metastasis, and define personalized therapies for cancer patients with obesity as a comorbidity.
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http://dx.doi.org/10.3390/ijms21031172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036786PMC
February 2020

Single-Cell Gene Expression Analyses Reveal Distinct Self-Renewing and Proliferating Subsets in the Leukemia Stem Cell Compartment in Acute Myeloid Leukemia.

Cancer Res 2020 02 29;80(3):458-470. Epub 2019 Nov 29.

Division of Hematology, Oncology, and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, Minnesota.

Standard chemotherapy for acute myeloid leukemia (AML) targets proliferative cells and efficiently induces complete remission; however, many patients relapse and die of their disease. Relapse is caused by leukemia stem cells (LSC), the cells with self-renewal capacity. Self-renewal and proliferation are separate functions in normal hematopoietic stem cells (HSC) in steady-state conditions. If these functions are also separate functions in LSCs, then antiproliferative therapies may fail to target self-renewal, allowing for relapse. We investigated whether proliferation and self-renewal are separate functions in LSCs as they often are in HSCs. Distinct transcriptional profiles within LSCs of / murine AML were identified using single-cell RNA sequencing. Single-cell qPCR revealed that these genes were also differentially expressed in primary human LSCs and normal human HSPCs. A smaller subset of these genes was upregulated in LSCs relative to HSPCs; this subset of genes constitutes "LSC-specific" genes in human AML. To assess the differences between these profiles, we identified cell surface markers, CD69 and CD36, whose genes were differentially expressed between these profiles. mouse reconstitution assays resealed that only CD69 LSCs were capable of self-renewal and were poorly proliferative. In contrast, CD36 LSCs were unable to transplant leukemia but were highly proliferative. These data demonstrate that the transcriptional foundations of self-renewal and proliferation are distinct in LSCs as they often are in normal stem cells and suggest that therapeutic strategies that target self-renewal, in addition to proliferation, are critical to prevent relapse and improve survival in AML. SIGNIFICANCE: These findings define and functionally validate a self-renewal gene profile of leukemia stem cells at the single-cell level and demonstrate that self-renewal and proliferation are distinct in AML. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/3/458/F1.large.jpg.
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http://dx.doi.org/10.1158/0008-5472.CAN-18-2932DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002190PMC
February 2020

R-spondin 2 Drives Liver Tumor Development in a Yes-Associated Protein-Dependent Manner.

Hepatol Commun 2019 Nov 3;3(11):1496-1509. Epub 2019 Sep 3.

Masonic Cancer Center University of Minnesota Minneapolis MN.

Each year, more than 25,000 people succumb to liver cancer in the United States, and this neoplasm represents the second cause of cancer-related death globally. R-spondins (RSPOs) are secreted regulators of Wnt signaling that function in development and promote tissue stem cell renewal. In cancer, RSPOs 2 and 3 are oncogenes first identified by insertional mutagenesis screens in tumors induced by mouse mammary tumor virus and by transposon mutagenesis in the colonic epithelium of rodents. has been reported to be activated by chromosomal rearrangements in colorectal cancer and overexpressed in a subset of hepatocellular carcinoma. Using human liver tumor gene expression data, we first discovered that a subset of liver cancers were characterized by high levels of in contrast to low levels in adjacent nontumor tissue. To determine if RSPOs are capable of inducing liver tumors, we used an model from which we found that overexpression of in the liver promoted Wnt signaling, hepatomegaly, and enhanced liver tumor formation when combined with loss of transformation-related protein 53 (). Moreover, the Hippo/yes-associated protein (Yap) pathway has been implicated in many human cancers, influencing cell survival. Histologic and gene expression studies showed activation of Wnt/β-catenin and Hippo/Yap pathways following overexpression. We demonstrate that knockdown of leads to reduced tumor penetrance following overexpression in the context of loss of overexpression leads to tumor formation in the mouse liver in a Hippo/Yap-dependent manner. Overall, our results suggest a role for Yap in the initiation and progression of liver tumors and uncover a novel pathway activated in RSPO2-induced malignancies. We show that RSPO2 promotes liver tumor formation and and that RSPO2's oncogenic activity requires Hippo/Yap activation in hepatocytes. Both RSPO2 and YAP1 are suggested to represent novel druggable targets in Wnt-driven tumors of the liver.
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http://dx.doi.org/10.1002/hep4.1422DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6824083PMC
November 2019

CD200 Checkpoint Reversal: A Novel Approach to Immunotherapy.

Clin Cancer Res 2020 01 17;26(1):232-241. Epub 2019 Oct 17.

Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.

Purpose: Advances in immunotherapy have revolutionized care for some patients with cancer. However, current checkpoint inhibitors are associated with significant toxicity and yield poor responses for patients with central nervous system tumors, calling into question whether cancer immunotherapy can be applied to glioblastoma multiforme. We determined that targeting the CD200 activation receptors (CD200AR) of the CD200 checkpoint with a peptide inhibitor (CD200AR-L) overcomes tumor-induced immunosuppression. We have shown the clinical efficacy of the CD200AR-L in a trial in companion dogs with spontaneous high-grade glioma. Addition of the peptide to autologous tumor lysate vaccines significantly increased the median overall survival to 12.7 months relative to tumor lysate vaccines alone, 6.36 months.

Experimental Design: This study was developed to elucidate the mechanism of the CD200ARs and develop a humanized peptide inhibitor. We developed macrophage cell lines with each of four CD200ARs knocked out to determine their binding specificity and functional response. Using proteomics, we developed humanized CD200AR-L to explore their effects on cytokine/chemokine response, dendritic cell maturation and CMV pp65 antigen response in human CD14 cells. GMP-grade peptide was further validated for activity.

Results: We demonstrated that the CD200AR-L specifically targets a CD200AR complex. Moreover, we developed and validated a humanized CD200AR-L for inducing chemokine response, stimulating immature dendritic cell differentiation and significantly enhanced an antigen-specific response, and determined that the use of the CD200AR-L downregulated the expression of CD200 inhibitory and PD-1 receptors.

Conclusions: These results support consideration of a CD200AR-L as a novel platform for immunotherapy against multiple cancers including glioblastoma multiforme.
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http://dx.doi.org/10.1158/1078-0432.CCR-19-2234DOI Listing
January 2020

SEMA4C is a novel target to limit osteosarcoma growth, progression, and metastasis.

Oncogene 2020 01 3;39(5):1049-1062. Epub 2019 Oct 3.

Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.

Semaphorins, specifically type IV, are important regulators of axonal guidance and have been increasingly implicated in poor prognoses in a number of different solid cancers. In conjunction with their cognate PLXNB family receptors, type IV members have been increasingly shown to mediate oncogenic functions necessary for tumor development and malignant spread. In this study, we investigated the role of semaphorin 4C (SEMA4C) in osteosarcoma growth, progression, and metastasis. We investigated the expression and localization of SEMA4C in primary osteosarcoma patient tissues and its tumorigenic functions in these malignancies. We demonstrate that overexpression of SEMA4C promotes properties of cellular transformation, while RNAi knockdown of SEMA4C promotes adhesion and reduces cellular proliferation, colony formation, migration, wound healing, tumor growth, and lung metastasis. These phenotypic changes were accompanied by reductions in activated AKT signaling, G1 cell cycle delay, and decreases in expression of mesenchymal marker genes SNAI1, SNAI2, and TWIST1. Lastly, monoclonal antibody blockade of SEMA4C in vitro mirrored that of the genetic studies. Together, our results indicate a multi-dimensional oncogenic role for SEMA4C in metastatic osteosarcoma and more importantly that SEMA4C has actionable clinical potential.
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http://dx.doi.org/10.1038/s41388-019-1041-xDOI Listing
January 2020

Engineering Genetic Predisposition in Human Neuroepithelial Stem Cells Recapitulates Medulloblastoma Tumorigenesis.

Cell Stem Cell 2019 09 13;25(3):433-446.e7. Epub 2019 Jun 13.

Division of Pediatric Neurology, Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA; Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA; Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA.

Human neural stem cell cultures provide progenitor cells that are potential cells of origin for brain cancers. However, the extent to which genetic predisposition to tumor formation can be faithfully captured in stem cell lines is uncertain. Here, we evaluated neuroepithelial stem (NES) cells, representative of cerebellar progenitors. We transduced NES cells with MYCN, observing medulloblastoma upon orthotopic implantation in mice. Significantly, transcriptomes and patterns of DNA methylation from xenograft tumors were globally more representative of human medulloblastoma compared to a MYCN-driven genetically engineered mouse model. Orthotopic transplantation of NES cells generated from Gorlin syndrome patients, who are predisposed to medulloblastoma due to germline-mutated PTCH1, also generated medulloblastoma. We engineered candidate cooperating mutations in Gorlin NES cells, with mutation of DDX3X or loss of GSE1 both accelerating tumorigenesis. These findings demonstrate that human NES cells provide a potent experimental resource for dissecting genetic causation in medulloblastoma.
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http://dx.doi.org/10.1016/j.stem.2019.05.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6731167PMC
September 2019

A comparison of risk factors for metastasis at diagnosis in humans and dogs with osteosarcoma.

Cancer Med 2019 06 21;8(6):3216-3226. Epub 2019 Apr 21.

Division of Pediatric Epidemiology and Clinical Research, School of Medicine, University of Minnesota, Minneapolis, Minnesota.

Background: Canine osteosarcoma (OS) is a relevant spontaneous model for human OS. Identifying similarities in clinical characteristics associated with metastasis at diagnosis in both species may substantiate research aimed at using canine OS as a model for identifying mechanisms driving distant spread in the human disease.

Methods: This retrospective study included dog OS cases from three academic veterinary hospitals and human OS cases from the Surveillance, Epidemiology, and End Results program. Associations between clinical factors and metastasis at diagnosis were estimated using logistic regression models.

Results: In humans, those with trunk tumors had higher odds of metastasis at diagnosis compared to those with lower limb tumors (OR = 2.38, 95% CI: 1.51, 3.69). A similar observation was seen in dogs with trunk tumors compared to dogs with forelimb tumors (OR = 3.28, 95% CI 1.36, 7.50). Other associations were observed in humans but not in dogs. Humans aged 20-29 years had lower odds of metastasis at diagnosis compared to those aged 10-14 years (OR = 0.67, 95% CI: 0.47, 0.96); every 1-cm increase in tumor size was associated with a 6% increase in the odds of metastasis at diagnosis (95% CI: 1.04, 1.08); compared to those with a white, non-Hispanic race, higher odds were observed among those with a black, non-Hispanic race (OR: 1.51, 95% CI: 1.04, 2.16), and those with a Hispanic origin (OR 1.35, 95% CI: 1.00, 1.81).

Conclusion: A common mechanism may be driving trunk tumors to progress to detectable metastasis prior to diagnosis in both species.
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http://dx.doi.org/10.1002/cam4.2177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558582PMC
June 2019

HBx-K130M/V131I Promotes Liver Cancer in Transgenic Mice via AKT/FOXO1 Signaling Pathway and Arachidonic Acid Metabolism.

Mol Cancer Res 2019 07 11;17(7):1582-1593. Epub 2019 Apr 11.

State Key Laboratory of Chinese Medicine and Molecular Pharmacology (Incubation), The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.

Chronic hepatitis B viral (HBV) infection remains a high underlying cause for hepatocellular carcinoma (HCC) worldwide, while the genetic mechanisms behind this remain unclear. This study elucidated the mechanisms contributing to tumor development induced by the HBV X (HBx) gene of predominantly Asian genotype B HBV and its common HBx variants. To compare the potential tumorigenic effects of K130M/V131I (Mut) and wild-type (WT) HBx on HCC, the () transposon system was used to deliver HBx Mut and WT into the livers of fumarylacetoacetate hydrolase ()-deficient mice and in the context of () deficiency. From our results, HBx Mut had a stronger tumorigenic effect than its WT variant. Also, inflammation, necrosis, and fibrosis were evident in HBx experimental animals. Reduction of forkhead box O1 (FOXO1) with increased phosphorylation of upstream serine/threonine kinase (AKT) was detected under HBx Mut overexpression. Thus, it is proposed that HBx Mut enhances disease progression by reducing FOXO1 via phosphorylation of AKT. At the metabolomic level, HBx altered the expression of genes that participated in arachidonic acid (AA) metabolism, as a result of inflammation via accumulation of proinflammatory factors such as prostaglandins and leukotriene in liver. Taken together, the increased rate of HCC observed in chronic hepatitis B patients with K130M/V131I-mutated X protein, may be due to changes in AA metabolism and AKT/FOXO1 signaling. IMPLICATIONS: Our findings suggested that HBx-K130M/V131I-mutant variant promoted HCC progression by activating AKT/FOXO1 pathway and inducing stronger inflammation in liver via AA metabolism.
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http://dx.doi.org/10.1158/1541-7786.MCR-18-1127DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6610579PMC
July 2019

Targeted Inhibition of the Dual Specificity Phosphatases DUSP1 and DUSP6 Suppress MPNST Growth via JNK.

Clin Cancer Res 2019 07 1;25(13):4117-4127. Epub 2019 Apr 1.

Cincinnati Children's Hospital Medical Center, Cincinnati, OH.

Purpose: In neurofibromatosis type 1 (NF1) and in highly aggressive malignant peripheral nerve sheath tumors (MPNSTs), constitutively active RAS-GTP and increased MAPK signaling are important in tumorigenesis. Dual specificity phosphatases (DUSPs) are negative regulators of MAPK signaling that dephosphorylate p38, JNK, and ERK in different settings. Although often acting as tumor suppressors, DUSPs may also act as oncogenes, helping tumor cells adapt to high levels of MAPK signaling. We hypothesized that inhibiting DUSPs might be selectively toxic to cells from NF1-driven tumors.

Experimental Design: We examined DUSP gene and protein expression in neurofibroma and MPNSTs. We used small hairpin RNA (shRNA) to knock down DUSP1 and DUSP6 to evaluate cell growth, downstream MAPK signaling, and mechanisms of action. We evaluated the DUSP inhibitor, (E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI), in MPNST cell lines and in cell-line and patient-derived MPNST xenografts.

Results: DUSP1 and DUSP6 are expressed in NF1-deleted tumors. Knockdown of DUSP1 and DUSP6, alone or in combination, reduced MPNST cell growth and led to ERK and JNK hyperactivation increasing downstream TP53 and p-ATM. The DUSP inhibitor, BCI, diminished the survival of NF1-deleted Schwann cells and MPNST cell lines through activation of JNK. , treatment of an established cell-line xenograft or a novel patient-derived xenograft (PDX) of MPNSTs with BCI increased ERK and JNK activation, caused tumor necrosis and fibrosis, and reduced tumor volume in one model.

Conclusions: Targeting DUSP1 and DUSP6 genetically or with BCI effectively inhibits MPNST cell growth and promotes cell death, and in xenograft models. The data support further investigation of DUSP inhibition in MPNSTs.
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http://dx.doi.org/10.1158/1078-0432.CCR-18-3224DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6606396PMC
July 2019

Identification of candidate neoantigens produced by fusion transcripts in human osteosarcomas.

Sci Rep 2019 01 23;9(1):358. Epub 2019 Jan 23.

Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.

Osteosarcomas are characterized by highly disrupted genomes. Although osteosarcomas lack common fusions, we find evidence of many tumour specific gene-gene fusion transcripts, likely due to chromosomal rearrangements and expression of transcription-induced chimeras. Most of the fusions result in out-of-frame transcripts, potentially capable of producing long novel protein sequences and a plethora of neoantigens. To identify fusions, we explored RNA-sequencing data to obtain detailed knowledge of transcribed fusions, by creating a novel program to compare fusions identified by deFuse to de novo transcripts generated by Trinity. This allowed us to confirm the deFuse results and identify unusual splicing patterns associated with fusion events. Using various existing tools combined with this custom program, we developed a pipeline for the identification of fusion transcripts applicable as targets for immunotherapy. In addition to identifying candidate neoantigens associated with fusions, we were able to use the pipeline to establish a method for measuring the frequency of fusion events, which correlated to patient outcome, as well as highlight some similarities between canine and human osteosarcomas. The results of this study of osteosarcomas underscores the numerous benefits associated with conducting a thorough analysis of fusion events within cancer samples.
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http://dx.doi.org/10.1038/s41598-018-36840-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344567PMC
January 2019

Insertional Mutagenesis Reveals Important Genetic Drivers of Central Nervous System Embryonal Tumors.

Cancer Res 2019 03 23;79(5):905-917. Epub 2019 Jan 23.

Division of Hematology, The Hospital for Sick Children, Toronto, Ontario, Canada.

Medulloblastoma and central nervous system primitive neuroectodermal tumors (CNS-PNET) are aggressive, poorly differentiated brain tumors with limited effective therapies. Using () transposon mutagenesis, we identified novel genetic drivers of medulloblastoma and CNS-PNET. Cross-species gene expression analyses classified -driven tumors into distinct medulloblastoma and CNS-PNET subgroups, indicating they resemble human Sonic hedgehog and group 3 and 4 medulloblastoma and CNS neuroblastoma with activation. This represents the first genetically induced mouse model of CNS-PNET and a rare model of group 3 and 4 medulloblastoma. We identified several putative proto-oncogenes including , and . Genetic manipulation of these genes demonstrated a robust impact on tumorigenesis and . We also determined that FOXR2 interacts with N-MYC, increases C-MYC protein stability, and activates FAK/SRC signaling. Altogether, our study identified several promising therapeutic targets in medulloblastoma and CNS-PNET. SIGNIFICANCE: A transposon-induced mouse model identifies several novel genetic drivers and potential therapeutic targets in medulloblastoma and CNS-PNET.
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http://dx.doi.org/10.1158/0008-5472.CAN-18-1261DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6397665PMC
March 2019

Sodium tanshinone IIA sulfonate ameliorates hepatic steatosis by inhibiting lipogenesis and inflammation.

Biomed Pharmacother 2019 Mar 18;111:68-75. Epub 2018 Dec 18.

The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China; Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong. Electronic address:

Non-alcoholic fatty liver disease (NAFLD) is becoming an epidemic disease in adults and children worldwide. Importantly, there are currently no approved treatments available for NAFLD. This study aims to investigate the potential applications of sodium tanshinone IIA sulfonate (STS) on improving the NAFLD condition using both in vitro and in vivo approaches. The results showed that STS markedly inhibited lipid accumulation in oleic acid (OA) and palmitic acid (PA) treated HepG2 and primary immortalized human hepatic (PIH) cells. STS suppressed lipogenesis by inhibiting expression of sterol regulatory element binding transcription factor 1 (SREBF1), fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD). In addition, STS reduced inflammation in cells treated with OA-PA, shown by decreased transcriptional levels of tumor necrosis factor (TNF), transforming growth factor beta 1 (TGFB1) and interleukin 1 beta (IL1B). Consistently, protective effects on hepatic steatosis in db/db mice were observed after STS administration, demonstrated by decreased lipid accumulation in mouse hepatocytes. This protective effect might be associated with STS induced activation of sirtuin 1 (SIRT1)/protein kinase AMP-activated catalytic subunit alpha 1 (PRKAA1) pathways. Our findings suggest a potential therapeutic role for STS in the treatment of NAFLD.
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http://dx.doi.org/10.1016/j.biopha.2018.12.019DOI Listing
March 2019

CRISPR/Cas9-Based Positive Screens for Cancer-Related Traits.

Methods Mol Biol 2019 ;1907:137-144

Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.

Since the advent of large-scale, detailed descriptive cancer genomics studies at the beginning of the century, such as The Cancer Genome Atlas (TCGA), labs around the world have been working to make this data useful. Data like these can be made more useful by comparison with complementary functional genomic data. One new example is the application of CRISPR/Cas9-based library screening for cancer-related traits in cell lines. Such screens can reveal genome-wide suppressors of tumorigenesis and metastasis. Here we describe the use of widely available lentiviral libraries for such screens in cultured cell lines.
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http://dx.doi.org/10.1007/978-1-4939-8967-6_11DOI Listing
July 2019
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