Dawn E Quelle

Dawn E Quelle
University of Iowa | UI · Department of Neuroscience and Pharmacology

Doctor of Philosophy

About

113
Publications
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Introduction
We study molecular mechanisms driving cancer with an emphasis on identifying druggable pathways so we can translate findings into better patient care in the clinic. Our studies employ cultured cells, human tumor specimens and animal models of cancer. Most of our current work seeks to define prognostic biomarkers and clinically relevant drug targets in neuroendocrine tumors and sarcomas (particularly malignant peripheral nerve sheath tumors)

Publications

Publications (113)
Article
Full-text available
Purpose Renal and hematological toxicity are side effects and dose-limiting factors of Peptide Receptor Radionuclide Therapy (PRRT). We aimed to assess the changes in renal and hematological function and associations with survival in neuroendocrine tumor (NET) patients treated with PRRT. Methods A retrospective cohort of 448 NET patients treated w...
Article
Full-text available
Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive, Ras-driven sarcomas characterized by loss of the NF1 tumor suppressor gene and hyperactivation of MEK and CDK4/6 kinases. MPNSTs lack effective therapies. We recently demonstrated remarkable efficacy of dual CDK4/6-MEK inhibition in mice with de novo MPNSTs, which was heightened by c...
Article
Full-text available
Functional copy-number alterations (fCNAs) are DNA copy-number changes with concordant differential gene expression. These are less likely to be bystander genetic lesions and could serve as robust and reproducible tumor biomarkers. To identify candidate fCNAs in neuroendocrine tumors (NETs), we integrated chromosomal microarray (CMA) and RNA-seq di...
Article
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Cognitive or motor impairment is common among individuals with neurofibromatosis type 1 (NF1), an autosomal dominant tumor‐predisposition disorder. As many as 70% of children with NF1 report difficulties with spatial/working memory, attention, executive function, and fine motor movements. In contrast to the utilization of various Nf1 mouse models,...
Preprint
Full-text available
Functional copy number alterations (fCNAs) are DNA copy number changes with concordant differential gene expression. These are less likely to be bystander genetic lesions and could serve as robust and reproducible tumor biomarkers. To identify candidate fCNAs in neuroendocrine tumors (NETs), we integrated chromosomal microarray (CMA) and RNA-seq di...
Article
Neuroendocrine neoplasms (NENs) are rare cancers that arise from neuroendocrine cells. NENs are classified as well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Small bowel NETs (SBNETs) and pancreatic NETs (PNETs) are generally slow growing but they commonly metastasize to the liver and can...
Article
Full-text available
Malignant peripheral nerve sheath tumors (MPNSTs) are deadly sarcomas, which desperately need effective therapies. Half of all MPNSTs arise in patients with neurofibromatosis type I (NF1), a common inherited disease. NF1 patients can develop benign lesions called plexiform neurofibromas (PNFs), often in adolescence, and over time, some PNFs, but no...
Preprint
Full-text available
Malignant peripheral nerve sheath tumors (MPNSTs) are deadly sarcomas that desperately need effective therapies. Half of all MPNSTs arise in patients with Neurofibromatosis Type I (NF1), a common inherited disease. NF1 patients can develop benign lesions called Plexiform Neurofibromas (PNFs), often in adolescence, and over time some PNFs, but not a...
Article
Purpose: Malignant peripheral nerve sheath tumors (MPNSTs) are lethal, Ras-driven sarcomas that lack effective therapies. We investigated effects of targeting CDK4/6, MEK, and/or programmed death-ligand 1 (PD-L1) in preclinical MPNST models. Experimental design: Patient-matched MPNSTs and precursor lesions were examined by FISH, RNAseq, IHC, and...
Preprint
Small bowel neuroendocrine tumors (SBNETs) originate from enterochromaffin cells in the intestine which synthesize and secrete serotonin. SBNETs express high levels of tryptophan hydroxylase 1 (Tph1), a key enzyme in serotonin biosynthesis. Patients with high serotonin level may develop carcinoid syndrome, which can be treated with somatostatin ana...
Article
Full-text available
Objective Inflammation is present in many diseases and identification of immune cell infiltration is a common assessment. CD138 (syndecan-1) is a recommended immunohistochemical marker for human plasmacytes although it is also expressed in various epithelia and tumors. Similarly, CD138 is a marker for murine plasmacytes, but its tissue immunostaini...
Article
Malignant peripheral nerve sheath tumors (MPNSTs) are deadly, Ras-driven sarcomas that lack effective therapies. Many tumors are unresectable and toxic chemotherapies are ineffectual. The sensitivity of MPNSTs to immune checkpoint blockade (ICB) therapies is not known, although sarcomas are generally unresponsive. Patient tumor analyses comparing M...
Chapter
The protein products of the INK4a/ARF gene locus, p16INK4a and ARF, activate distinct protective checkpoints that inhibit cell proliferation and maintain genomic stability in response to cellular stresses. As such, both factors play a central role in tumor suppression and their inactivation is one of the most frequent events in human cancer. Unique...
Article
Full-text available
Neuroendocrine neoplasia (NENs) are a complex and heterogeneous group of cancers that can arise from neuroendocrine tissues throughout the body and differentiate them from other tumors. Their low incidence and high diversity make many of them orphan conditions characterized by a low incidence and few dedicated clinical trials. Study of the molecula...
Article
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The DNA methyltransferase inhibitor decitabine has classically been used to reactivate silenced genes and as a pre-treatment for anti-cancer therapies. In a new variation of this idea, this study explores the concept of adding low-dose decitabine following administration of chemotherapy to bolster therapeutic efficacy. We find that addition of deci...
Article
Full-text available
Background Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas with complex molecular and genetic alterations. Powerful tumor suppressors CDKN2A and TP53 are commonly disrupted along with NF1, a gene that encodes a negative regulator of Ras. Many additional factors have been implicated in MPNST pathogenesis. A greater understa...
Article
Full-text available
Pancreatic neuroendocrine tumors (pNETs) are unique, slow-growing malignancies whose molecular pathogenesis is incompletely understood. With rising incidence of pNETs over the last four decades, larger and more comprehensive ‘omic’ analyses of patient tumors have led to a clearer picture of the pNET genomic landscape and transcriptional profiles fo...
Preprint
Full-text available
Background: Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that display complex molecular and genetic alterations. Powerful tumor suppressors CDKN2A and TP53 are commonly disrupted in these lesions along with NF1, a gene that encodes a negative regulator of Ras. Many additional factors have been implicated in MPNST pathog...
Article
Full-text available
Pancreatic neuroendocrine tumors (pNETs) are difficult-to-treat neoplasms whose incidence is rising. Greater understanding of pNET pathogenesis is needed to identify new biomarkers and targets for improved therapy. RABL6A, a novel oncogenic GTPase, is highly expressed in patient pNETs and required for pNET cell proliferation and survival in vitro....
Article
Full-text available
Schwann cells are normally quiescent, myelinating glia cells of the peripheral nervous system. Their aberrant proliferation and transformation underlie the development of benign tumors (neurofibromas) as well as deadly malignant peripheral nerve sheath tumors (MPNSTs). We discovered a new driver of MPNSTs, an oncogenic GTPase named RABL6A, that fun...
Article
Full-text available
Pancreatic neuroendocrine neoplasms (pNENs) are slow growing cancers of increasing incidence that lack effective treatments once they become metastatic. Unfortunately, nearly half of pNEN patients present with metastatic liver tumors at diagnosis and current therapies fail to improve overall survival. Pre-clinical models of pNEN metastasis are need...
Article
Full-text available
Additional prognostic and therapeutic biomarkers effective across different histological types of sarcoma are needed. Herein we evaluate expression of TAZ and YAP, the p53-MDM2 axis, and RABL6A, a novel oncoprotein with potential ties to both pathways, in sarcomas of different histological types. Immunohistochemical staining of a tissue microarray...
Preprint
Full-text available
Pancreatic neuroendocrine tumors (pNETs) are difficult-to-treat neoplasms whose incidence is rising. Greater understanding of pNET pathogenesis is needed to identify new biomarkers and targets for improved therapy. RABL6A, a novel oncogenic GTPase, is highly expressed in patient pNETs and required for pNET cell proliferation and survival in vitro....
Article
Full-text available
Precision medicine relies on a detailed molecular understanding of disease pathogenesis. Here, we consider urgently needed therapeutic options for malignant peripheral nerve sheath tumors (MPNSTs) based on emerging insights into druggable pathway alterations found to drive this deadly cancer. Recent observations demonstrate an essential role for an...
Article
Full-text available
Aryl hydrocarbon receptor (AHR) agonists such as dioxin have been associated with obesity and the development of diabetes. Whole-body Ahr knockout mice on high-fat diet (HFD) have been shown to resist obesity and hepatic steatosis. Tissue-specific knockout of Ahr in mature adipocytes via adiponectin-Cre exacerbates obesity while knockout in liver i...
Article
2552 Background: Identification of tumor characteristics that may be associated with survival in patients with glioblastoma (GBM) has been largely characterized by IDH mutations and MGMT promoter methylation status. However, these genetic changes and other currently available data are not sufficient to explain the longevity experienced by a subset...
Article
Full-text available
Sarcomas represent one of the most challenging tumor types to treat due to their diverse nature and our incomplete understanding of their underlying biology. Recent work suggests cyclin-dependent kinase (CDK) pathway activation is a powerful driver of sarcomagenesis. CDK proteins participate in numerous cellular processes required for normal cell f...
Article
Full-text available
Neurofibromatosis type 1 (NF1) is a rare, autosomal dominant disease with variable clinical presentations. Large animal models are useful to help dissect molecular mechanisms, determine relevant biomarkers, and develop effective therapeutics. Here, we studied a NF1 minipig model (NF1+/ex42del) for the first 12 months of life to evaluate phenotype d...
Article
Purpose: Malignant peripheral nerve sheath tumors (MPNSTs) are deadly sarcomas that lack effective therapies. In most MPNSTs, the retinoblastoma (RB1) tumor suppressor is disabled by hyperactivation of cyclin dependent kinases (CDKs), commonly through loss of CDK inhibitory proteins such as p27(Kip1). RABL6A is an inhibitor of RB1 whose role in MP...
Article
Full-text available
Genetically modified swine disease models are becoming increasingly important for studying molecular, physiological and pathological characteristics of human disorders. Given the limited history of these model systems, there remains a great need for proven molecular reagents in swine tissue. Here, to provide a resource for neurological models of di...
Article
Purpose: Pancreatic neuroendocrine tumors (pNETs) are uncommon malignancies noted for their propensity to metastasize and comparatively favorable prognosis. Although both the treatment options and clinical outcomes have improved in the last decades, most patients will die of metastatic disease. New systemic therapies are needed. Experimental desi...
Article
Neurofibromatosis Type 1 (NF1) is an autosomal dominant genetic disorder resulting from germline mutations in the NF1 gene, which encodes neurofibromin. Patients experience a variety of symptoms, but pain in the context of NF1 remains largely under-recognized. Here, we characterize nociceptive signaling and pain behaviors in a miniswine harboring a...
Article
Hyperactivated AKT/mTOR signaling is a hallmark of pancreatic neuroendocrine tumors (PNETs). Drugs targeting this pathway are used clinically but tumor resistance invariably develops. A better understanding of factors regulating AKT/mTOR signaling and PNET pathogenesis is needed to improve current therapies. We discovered that RABL6A, a new oncogen...
Preprint
Full-text available
Genetically modified porcine disease models are becoming increasingly important for studying molecular, physiological and pathological characteristics of human disorders. Given their limited history, there remains a great need for proven reagents in swine tissue. To provide a resource for neurological models of disease, we validated antibodies by i...
Preprint
Full-text available
Neurofibromatosis Type 1 (NF1) is an autosomal dominant genetic disorder resulting from germline mutations in the NF1 gene, which encodes neurofibromin. Patients experience a variety of symptoms, but pain in the context of NF1 remains largely underrecognized. Here, we characterize nociceptive signaling and pain behaviors in a miniswine harboring a...
Article
Full-text available
Mutations in the “guardian of the genome” TP53 predominate in solid tumors. In addition to loss of tumor suppressor activity, a specific subset of missense mutations confers additional oncogenic properties. These “gain-of-function” (GOF) mutations portend poor prognosis across cancer types regardless of treatment. Our objective in this study was to...
Article
Neurofibromatosis type 1 (NF1) is a genetic condition caused by mutations in the tumor suppressor gene, NF1 . People with NF1 have an increased risk for benign and malignant tumors of the CNS/PNS (e.g. neurofibromas, malignant peripheral nerve sheath tumors, gliomas) and other tumor types (e.g. leukemias, breast cancer, etc.). Additionally, those a...
Article
Full-text available
Loss of the NF1 tumor suppressor gene causes the autosomal dominant condition, neurofibromatosis type 1 (NF1). Children and adults with NF1 suffer from pathologies including benign and malignant tumors to cognitive deficits, seizures, growth abnormalities, and peripheral neuropathies. NF1 encodes neurofibromin, a Ras-GTPase activating protein, and...
Article
Background: This study explores whether objective, quantitative radiomic biomarkers derived from magnetic resonance (MR), positron emission tomography (PET), and computed tomography (CT) may be useful in reliably distinguishing malignant peripheral nerve sheath tumors (MPNST) from benign plexiform neurofibromas (PN). Methods: A registration and...
Preprint
Full-text available
Mutations in the “guardian of the genome” TP53 predominate in solid tumors. In addition to loss of tumor suppressor activity, a specific subset of missense mutations confers additional oncogenic properties. These “gain-of-function” (GOF) mutations portend poor prognosis across cancer types regardless of treatment. Our objective in this study was to...
Article
Full-text available
MYST histone acetyltransferases have crucial functions in transcription, replication and DNA repair and are hence implicated in development and cancer. Here we characterise Myst2/Kat7/Hbo1 protein interactions in mouse embryonic stem cells by affinity purification coupled to mass spectrometry. This study confirms that in embryonic stem cells Myst2...
Article
Neurofibromatosis type 1 (NF1) is a common, cancer-predisposing disease caused by mutations in the NF1 tumor gene. Patients with NF1 have an increased risk for benign and malignant tumors of the nervous system (e.g., neurofibromas, malignant peripheral nerve sheath tumors, gliomas) and other tissues (e.g., leukemias, rhabdomyosarcoma, etc.) as well...
Article
Introduction: A better molecular understanding of pancreatic neuroendocrine tumors (PNETs) is needed to improve patient diagnosis and treatment. Everolimus (mTOR inhibitor) is a standard-of-care therapy for PNET patients based on aberrant activation of the PI3K/Akt/mTOR kinase pathway in tumors. However, sustained mTOR inhibition paradoxically prom...
Article
Full-text available
Leukemia accepted article preview online, 12 April 2017. doi:10.1038/leu.2017.115.
Article
Full-text available
The protein products of the INK4a/ARF gene locus, p16INK4a and ARF, activate distinct protective checkpoints that inhibit cell proliferation and maintain genomic stability in response to cellular stresses. As such, both factors play a central role in tumor suppression and their inactivation is one of the most frequent events in human cancer. Unique...
Article
Full-text available
Large-animal cancer models are needed to advance the development of innovative and clinically applicable tumor diagnostic, therapeutic, and monitoring technologies. We developed a genetically modified porcine model of cancer based on a TP53 mutation, and established its utility for tracking tumorigenesis in vivo through non-invasive clinical imagin...
Article
Full-text available
Mechanisms of neuroendocrine tumor (NET) proliferation are poorly understood and therapies that effectively control NET progression and metastatic disease are limited. We found amplification of a putative oncogene, RABL6A, in primary human pancreatic NETs (PNETs) that correlated with high level RABL6A protein expression. Consistent with those resul...
Article
Full-text available
Nuclear Interactor of ARF and Mdm2 (NIAM, gene designation Tbrg1) is a largely unstudied inhibitor of cell proliferation that helps maintain chromosomal stability. It is a novel activator of the ARF-Mdm2-Tip60-p53 tumor suppressor pathway as well as other undefined pathways important for genome maintenance. To examine its predicted role as a tumor...
Conference Paper
Cancer remains the second deadliest disease in the United States, necessitating improvements in tumor diagnosis and treatment. Current model systems of cancer have been informative but also present challenges to translating promising imaging approaches and therapies to the clinic. The lack of a large animal model that accurately mimics human cancer...
Article
Cancer is the second deadliest disease in the United States, necessitating improvements in tumor diagnosis and treatment. Current model systems of cancer are informative, but translating promising imaging approaches and therapies to clinical practice has been challenging. In particular, the lack of a large-animal model that accurately mimics human...
Article
Silencing of tumor suppressor genes by DNA methyltransferase 1 (Dnmt1), dysregulated in human cancers, is essential for oncogenic transformation by the Ras protooncogene. Here, we provide evidence that Regulator of G protein Signaling 6 (RGS6) suppresses Ras‐induced cellular transformation by facilitating Tip60‐mediated Dnmt1 degradation and promot...
Article
Full-text available
Post-translational modifications of p53 are critical in modulating its tumor suppressive functions. Ubiquitylation, for example, plays a major role in dictating p53 stability, subcellular localization and transcriptional vs. non-transcriptional activities. Less is known about p53 acetylation. It has been shown to govern p53 transcriptional activity...
Article
Full-text available
The p53 tumor suppressor is controlled by an interactive network of factors that stimulate or inhibit its transcriptional activity. Within that network, Mdm2 functions as the major antagonist of p53 by promoting its ubiquitylation and degradation. Conversely, Tip60 activates p53 through direct association on target promoters as well as acetylation...
Article
Full-text available
RABL6A (RAB-like 6 isoform A) is a novel protein that was originally identified based on its association with the Alternative Reading Frame (ARF) tumor suppressor. ARF acts through multiple p53-dependent and p53-independent pathways to prevent cancer. How RABL6A functions, to what extent it depends on ARF and p53 activity, and its importance in nor...
Article
Full-text available
The RAS protooncogene has a central role in regulation of cell proliferation, and point mutations leading to oncogenic activation of Ras occur in a large number of human cancers. Silencing of tumor-suppressor genes by DNA methyltransferase 1 (Dnmt1) is essential for oncogenic cellular transformation by Ras, and Dnmt1 is overexpressed in numerous hu...
Article
Full-text available
Pancreatic ductal adenocarcinoma (PDAC) is characterized by early recurrence following pancreatectomy, rapid progression, and chemoresistance. Novel prognostic and predictive biomarkers are urgently needed to both stratify patients for clinical trials and select patients for adjuvant therapy regimens. This study sought to determine the biological s...
Article
Full-text available
Objectives: To determine which metrics of scholarly output have the most impact on decisions for faculty promotion, as new forms of scholarship are evolving at medical schools to answer an emerging need for increased skills specialization and interdisciplinary collaboration. Methods: University of Iowa Carver College of Medicine (UICCOM) data was u...
Article
Nuclear interactor of ARF and Mdm2, NIAM, is a novel regulator of the ARF-Mdm2-p53 tumor suppressor pathway. It collaborates with ARF, promotes p53 transcriptional activity, and is negatively regulated by Mdm2-mediated ubiquitination and proteasome degradation. How NIAM activates p53 is not known, however its ability to do so in ARF-null cells reve...
Article
Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Pancreatic ductal adenocarcinoma (PDAC) is an incurable malignancy with ineffective treatments and dismal median survival. The INK4a/ARF locus, which encodes the alternative reading frame (ARF) tumor suppressor, is commonly inactivated in PDAC tumors. We recently discove...
Article
Full-text available
Pancreatic ductal adenocarcinoma (PDAC) is an incurable, highly metastatic disease that is largely resistant to existing treatments. A better understanding of the genetic basis of PDAC metastasis should facilitate development of improved therapies. To that end, we developed a novel mouse xenograft model of PDAC metastasis to expedite testing of can...