Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 63
Filter
1.
Cancer Discov ; : OF1-OF9, 2024 Jun 11.
Article in English | MEDLINE | ID: mdl-38867349

ABSTRACT

Juvenile myelomonocytic leukemia (JMML) is a hematologic malignancy of young children caused by mutations that increase Ras signaling output. Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment, but patients with relapsed or refractory (advanced) disease have dismal outcomes. This phase II trial evaluated the safety and efficacy of trametinib, an oral MEK1/2 inhibitor, in patients with advanced JMML. Ten infants and children were enrolled, and the objective response rate was 50%. Four patients with refractory disease proceeded to HSCT after receiving trametinib. Three additional patients completed all 12 cycles permitted on study and continue to receive off-protocol trametinib without HSCT. The remaining three patients had progressive disease with two demonstrating molecular evolution by the end of cycle 2. Transcriptomic and proteomic analyses provided novel insights into the mechanisms of response and resistance to trametinib in JMML. ClinicalTrials.gov Identifier: NCT03190915. Significance: Trametinib was safe and effective in young children with relapsed or refractory JMML, a lethal disease with poor survival rates. Seven of 10 patients completed the maximum 12 cycles of therapy or used trametinib as a bridge to HSCT and are alive with a median follow-up of 24 months.

2.
Front Oncol ; 14: 1191217, 2024.
Article in English | MEDLINE | ID: mdl-38854737

ABSTRACT

Introduction: Approximately 50% of melanomas harbor an activating BRAFV600E mutation. Standard of care involves a combination of inhibitors targeting mutant BRAF and MEK1/2, the substrate for BRAF in the MAPK pathway. PTEN loss-of-function mutations occur in ~40% of BRAFV600E melanomas, resulting in increased PI3K/AKT activity that enhances resistance to BRAF/MEK combination inhibitor therapy. Methods: To compare the response of PTEN null to PTEN wild-type cells in an isogenic background, CRISPR/Cas9 was used to knock out PTEN in a melanoma cell line that harbors a BRAFV600E mutation. RNA sequencing, functional kinome analysis, and drug synergy screening were employed in the context of BRAF/MEK inhibition. Results: RNA sequencing and functional kinome analysis revealed that the loss of PTEN led to an induction of FOXD3 and an increase in expression of the FOXD3 target gene, ERBB3/HER3. Inhibition of BRAF and MEK1/2 in PTEN null, BRAFV600E cells dramatically induced the expression of ERBB3/HER3 relative to wild-type cells. A synergy screen of epigenetic modifiers and kinase inhibitors in combination with BRAFi/MEKi revealed that the pan ERBB/HER inhibitor, neratinib, could reverse the resistance observed in PTEN null, BRAFV600E cells. Conclusions: The findings indicate that PTEN null BRAFV600E melanoma exhibits increased reliance on ERBB/HER signaling when treated with clinically approved BRAFi/MEKi combinations. Future studies are warranted to test neratinib reversal of BRAFi/MEKi resistance in patient melanomas expressing ERBB3/HER3 in combination with its dimerization partner ERBB2/HER2.

3.
iScience ; 27(6): 110068, 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38872973

ABSTRACT

Most cells in solid tumors are exposed to oxygen levels between 0.5% and 5%. We developed an approach that allows collection, processing, and evaluation of cancer and non-cancer cells under physioxia, while preventing exposure to ambient air. This aided comparison of baseline and drug-induced changes in signaling pathways under physioxia and ambient oxygen. Using tumor cells from transgenic models of breast cancer and cells from breast tissues of clinically breast cancer-free women, we demonstrate oxygen-dependent differences in cell preference for epidermal growth factor receptor (EGFR) or platelet-derived growth factor receptor beta (PDGFRß) signaling. Physioxia caused PDGFRß-mediated activation of AKT and extracellular regulated kinase (ERK) that reduced sensitivity to EGFR and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) inhibition and maintained PDGFRß+ epithelial-mesenchymal hybrid cells with potential cancer stem cell (CSC) properties. Cells in ambient air displayed differential EGFR activation and were more sensitive to targeted therapies. Our data emphasize the importance of oxygen considerations in preclinical cancer research to identify effective drug targets and develop combination therapy regimens.

4.
bioRxiv ; 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38746313

ABSTRACT

Schwann cells are vital to development and maintenance of the peripheral nervous system and their dysfunction has been implicated in a range of neurological and neoplastic disorders, including NF2 -related schwannomatosis. We developed a novel human induced pluripotent stem cell (hiPSC) model to study Schwann cell differentiation in health and disease. We performed transcriptomic, immunofluorescence, and morphological analysis of hiPSC derived Schwann cell precursors (SPCs) and terminally differentiated Schwann cells (SCs) representing distinct stages of development. To validate our findings, we performed integrated, cross-species analyses across multiple external datasets at bulk and single cell resolution. Our hiPSC model of Schwann cell development shared overlapping gene expression signatures with human amniotic mesenchymal stem cell (hAMSCs) derived SCs and in vivo mouse models, but also revealed unique features that may reflect species-specific aspects of Schwann cell biology. Moreover, we identified gene co-expression modules that are dynamically regulated during hiPSC to SC differentiation associated with ear and neural development, cell fate determination, the NF2 gene, and extracellular matrix (ECM) organization. By cross-referencing results between multiple datasets, we identified new genes potentially associated with NF2 expression. Our hiPSC model further provides a tractable platform for studying Schwann cell development in the context of human disease.

6.
Clin Cancer Res ; 30(5): 1038-1053, 2024 03 01.
Article in English | MEDLINE | ID: mdl-38127282

ABSTRACT

PURPOSE: Plexiform neurofibromas (PNF) are benign peripheral nerve sheath tumors (PNST) associated with neurofibromatosis type 1 (NF1). Despite similar histologic appearance, these neoplasms exhibit diverse evolutionary trajectories, with a subset progressing to malignant peripheral nerve sheath tumor (MPNST), the leading cause of premature death in individuals with NF1. Malignant transformation of PNF often occurs through the development of atypical neurofibroma (ANF) precursor lesions characterized by distinct histopathologic features and CDKN2A copy-number loss. Although genomic studies have uncovered key driver events promoting tumor progression, the transcriptional changes preceding malignant transformation remain poorly defined. EXPERIMENTAL DESIGN: Here we resolve gene-expression profiles in PNST across the neurofibroma-to-MPNST continuum in NF1 patients and mouse models, revealing early molecular features associated with neurofibroma evolution and transformation. RESULTS: Our findings demonstrate that ANF exhibit enhanced signatures of antigen presentation and immune response, which are suppressed as malignant transformation ensues. MPNST further displayed deregulated survival and mitotic fidelity pathways, and targeting key mediators of these pathways, CENPF and BIRC5, disrupted the growth and viability of human MPNST cell lines and primary murine Nf1-Cdkn2a-mutant Schwann cell precursors. Finally, neurofibromas contiguous with MPNST manifested distinct alterations in core oncogenic and immune surveillance programs, suggesting that early molecular events driving disease progression may precede histopathologic evidence of malignancy. CONCLUSIONS: If validated prospectively in future studies, these signatures may serve as molecular diagnostic tools to augment conventional histopathologic diagnosis by identifying neurofibromas at high risk of undergoing malignant transformation, facilitating risk-adapted care.


Subject(s)
Nerve Sheath Neoplasms , Neurofibroma , Neurofibromatosis 1 , Neurofibrosarcoma , Animals , Humans , Mice , Gene Expression Profiling , Nerve Sheath Neoplasms/genetics , Neurofibroma/genetics , Neurofibromatosis 1/genetics , Neurofibrosarcoma/genetics
7.
J Nat Prod ; 86(8): 1968-1979, 2023 08 25.
Article in English | MEDLINE | ID: mdl-37531219

ABSTRACT

Six new ravidomycin analogs (1-4, 6, and 7) were isolated from Streptomyces sp. Am59 using UV- and LCMS-guided separation based on Global Natural Products Social (GNPS) molecular networking analysis. Furthermore, we isolated fucomycin V (9), which possesses the same chromophore as ravidomycin but features a d-fucopyranose instead of d-ravidosamine. This is the first report of 9 as a natural product. Four new analogs (10-13) of 9 were also isolated. The structures were elucidated by combined spectroscopic and computational methods. We also found an inconsistency with the published [α]D25 of deacetylravidomycin, which is reported to have a (-) sign. Instead, we observed a (+) specific rotation for the reported absolute configuration of deacetylravidomycin (containing d-ravidosamine). We confirmed the positive sign by reisolating deacetylravidomycin from S. ravidus and by deacetylating ravidomycin. Finally, antibacterial, antifungal, and cytotoxicity activities were determined for the compounds. Compared to deacetylravidomycin, the compounds 4-6, 9, 11, and 12 exhibited greater antibacterial selectivity.


Subject(s)
Antineoplastic Agents , Streptomyces , Streptomyces/chemistry , Aminoglycosides , Anti-Bacterial Agents/chemistry , Molecular Structure
8.
Clin Cancer Res ; 29(17): 3438-3456, 2023 09 01.
Article in English | MEDLINE | ID: mdl-37406085

ABSTRACT

PURPOSE: Plexiform neurofibromas (PNF) are peripheral nerve sheath tumors that cause significant morbidity in persons with neurofibromatosis type 1 (NF1), yet treatment options remain limited. To identify novel therapeutic targets for PNF, we applied an integrated multi-omic approach to quantitatively profile kinome enrichment in a mouse model that has predicted therapeutic responses in clinical trials for NF1-associated PNF with high fidelity. EXPERIMENTAL DESIGN: Utilizing RNA sequencing combined with chemical proteomic profiling of the functionally enriched kinome using multiplexed inhibitor beads coupled with mass spectrometry, we identified molecular signatures predictive of response to CDK4/6 and RAS/MAPK pathway inhibition in PNF. Informed by these results, we evaluated the efficacy of the CDK4/6 inhibitor, abemaciclib, and the ERK1/2 inhibitor, LY3214996, alone and in combination in reducing PNF tumor burden in Nf1flox/flox;PostnCre mice. RESULTS: Converging signatures of CDK4/6 and RAS/MAPK pathway activation were identified within the transcriptome and kinome that were conserved in both murine and human PNF. We observed robust additivity of the CDK4/6 inhibitor, abemaciclib, in combination with the ERK1/2 inhibitor, LY3214996, in murine and human NF1(Nf1) mutant Schwann cells. Consistent with these findings, the combination of abemaciclib (CDK4/6i) and LY3214996 (ERK1/2i) synergized to suppress molecular signatures of MAPK activation and exhibited enhanced antitumor activity in Nf1flox/flox;PostnCre mice in vivo. CONCLUSIONS: These findings provide rationale for the clinical translation of CDK4/6 inhibitors alone and in combination with therapies targeting the RAS/MAPK pathway for the treatment of PNF and other peripheral nerve sheath tumors in persons with NF1.


Subject(s)
Nerve Sheath Neoplasms , Neurofibroma, Plexiform , Neurofibroma , Neurofibromatosis 1 , Humans , Mice , Animals , Neurofibroma, Plexiform/etiology , Neurofibroma, Plexiform/genetics , Neurofibromatosis 1/drug therapy , Neurofibromatosis 1/genetics , MAP Kinase Signaling System , Proteomics , Nerve Sheath Neoplasms/drug therapy , Nerve Sheath Neoplasms/genetics , Protein Kinase Inhibitors/pharmacology , Neurofibroma/complications , Cyclin-Dependent Kinase 4/genetics
9.
Acad Med ; 98(2): 180-187, 2023 02 01.
Article in English | MEDLINE | ID: mdl-36538695

ABSTRACT

The transition from undergraduate medical education (UME) to graduate medical education (GME) constitutes a complex system with important implications for learner progression and patient safety. The transition is currently dysfunctional, requiring students and residency programs to spend significant time, money, and energy on the process. Applications and interviews continue to increase despite stable match rates. Although many in the medical community acknowledge the problems with the UME-GME transition and learners have called for prompt action to address these concerns, the underlying causes are complex and have defied easy fixes. This article describes the work of the Coalition for Physician Accountability's Undergraduate Medical Education to Graduate Medical Education Review Committee (UGRC) to apply a quality improvement approach and systems thinking to explore the underlying causes of dysfunction in the UME-GME transition. The UGRC performed a root cause analysis using the 5 whys and an Ishikawa (or fishbone) diagram to deeply explore problems in the UME-GME transition. The root causes of problems identified include culture, costs and limited resources, bias, systems, lack of standards, and lack of alignment. Using the principles of systems thinking (components, connections, and purpose), the UGRC considered interactions among the root causes and developed recommendations to improve the UME-GME transition. Several of the UGRC's recommendations stemming from this work are explained. Sustained monitoring will be necessary to ensure interventions move the process forward to better serve applicants, programs, and the public good.


Subject(s)
Education, Medical, Undergraduate , Internship and Residency , Humans , Root Cause Analysis , Education, Medical, Graduate , Students
10.
J Gen Intern Med ; 37(1): 125-129, 2022 01.
Article in English | MEDLINE | ID: mdl-33791934

ABSTRACT

BACKGROUND: With rising applications to internal medicine programs and pending changes in United States Medical Licensing Examination Step 1 score reporting, program directors desire transparent data for comparing applicants. The Department of Medicine Letters of Recommendation (DOM LORs) are frequently used to assess applicants and have the potential to provide clearly defined data on performance including stratification of a medical school class. Despite published guidelines on the expected content of the DOM LOR, these LORs do not always meet that need. OBJECTIVES: To better understand the degree to which DOM LORs comply with published guidelines. METHODS: We reviewed DOM LORs from 146 of 155 LCME-accredited medical schools in the 2019 Match cycle, assessing for compliance with published guidelines. RESULTS: Adherence to the recommendation for DOM LORs to provide a final characterization of performance relative to peers was low (68/146, 47%). Of those that provided a final characterization, 19/68 (28%) provided a quantitative measure, and 49/68 (72%) provided a qualitative descriptor. Only 17/49 (35%) with qualitative terms described those terms, and thirteen distinct qualitative scales were identified. Ranking systems varied, with seven different titles given to highest performers. Explanations about determination of ranking groups were provided in 12% of cases. CONCLUSIONS: Adherence to published guidelines for DOM LORs varies but is generally low. For program directors desiring transparent data to use in application review, clearly defined data on student performance, stratification groupings, and common language across schools could improve the utility of DOM LORs.


Subject(s)
Internship and Residency , Communication , Humans , Internal Medicine , United States
11.
J Patient Saf ; 18(3): 253-259, 2022 04 01.
Article in English | MEDLINE | ID: mdl-34387249

ABSTRACT

OBJECTIVES: This study aimed to determine whether patients in teaching hospitals are at higher risk of suffering from an adverse event during the summer trainee changeover period. METHODS: We performed a retrospective analysis of data from the Medicare Patient Safety Monitoring System, a medical-record abstraction-based database in the United States. Hospital admissions from 2010 to 2017 for acute myocardial infarction, heart failure, pneumonia, or a major surgical procedure were studied. Admissions were divided into nonsurgical (acute myocardial infarction, heart failure, or pneumonia) and surgical. Adverse event rates in July/August were compared with the rest of the year. Hospitals were stratified into major teaching, minor teaching, or nonteaching. Results were adjusted for patient demographics, comorbidities, and hospital characteristics. Outcomes were the adjusted odds of having at least 1 adverse event in July/August versus the rest of the year. RESULTS: We included 185,652 hospital admissions. The adjusted odds ratios (ORs) of suffering from at least one adverse event in a major teaching hospital in July/August was 0.83 (95% confidence interval [CI], 0.69-0.98) for nonsurgical patients and 1.09 (95% CI, 0.84-1.40) for surgical patients. In minor teaching hospitals, the adjusted ORs were 0.96 (95% CI, 0.88-1.04) for nonsurgical patients and 0.99 (95% CI, 0.87-1.12) for surgical patients. In nonteaching hospitals, the adjusted ORs were 0.98 (95% CI, 0.91-1.06) for nonsurgical patients and 1.10 (95% CI, 0.96-1.24) for surgical patients. CONCLUSIONS: Patients admitted to teaching hospitals in July/August are not at increased risk of adverse events. These findings should reassure patients and medical educators that patients are not excessively endangered by admission to the hospital during these months.


Subject(s)
Medicare , Myocardial Infarction , Aged , Hospital Mortality , Hospitalization , Hospitals, Teaching , Humans , Retrospective Studies , United States/epidemiology
12.
Sci Rep ; 11(1): 17029, 2021 08 23.
Article in English | MEDLINE | ID: mdl-34426604

ABSTRACT

Mutations in MAPT (microtubule-associated protein tau) cause frontotemporal dementia (FTD). MAPT mutations are associated with abnormal tau phosphorylation levels and accumulation of misfolded tau protein that can propagate between neurons ultimately leading to cell death (tauopathy). Recently, a p.A152T tau variant was identified as a risk factor for FTD, Alzheimer's disease, and synucleinopathies. Here we used induced pluripotent stem cells (iPSC) from a patient carrying this p.A152T variant to create a robust, functional cellular assay system for probing pathophysiological tau accumulation and phosphorylation. Using stably transduced iPSC-derived neural progenitor cells engineered to enable inducible expression of the pro-neural transcription factor Neurogenin 2 (Ngn2), we generated disease-relevant, cortical-like glutamatergic neurons in a scalable, high-throughput screening compatible format. Utilizing automated confocal microscopy, and an advanced image-processing pipeline optimized for analysis of morphologically complex human neuronal cultures, we report quantitative, subcellular localization-specific effects of multiple kinase inhibitors on tau, including ones under clinical investigation not previously reported to affect tau phosphorylation. These results demonstrate the potential for using patient iPSC-derived ex vivo models of tauopathy as genetically accurate, disease-relevant systems to probe tau biochemistry and support the discovery of novel therapeutics for tauopathies.


Subject(s)
Glutamates/metabolism , Image Processing, Computer-Assisted , Induced Pluripotent Stem Cells/metabolism , Models, Biological , Neurons/pathology , Proteomics , Tauopathies/pathology , tau Proteins/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Biomarkers/metabolism , Cell Line , Humans , Induced Pluripotent Stem Cells/drug effects , Nerve Tissue Proteins/metabolism , Neurons/drug effects , Phosphorylation/drug effects , Protein Kinases/metabolism , Pyridines/chemistry , Pyridines/pharmacology , Pyrimidines/chemistry , Pyrimidines/pharmacology , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology
13.
PLoS One ; 16(7): e0252048, 2021.
Article in English | MEDLINE | ID: mdl-34264955

ABSTRACT

Neurofibromatosis Type 2 (NF2) is an autosomal dominant genetic syndrome caused by mutations in the NF2 tumor suppressor gene resulting in multiple schwannomas and meningiomas. There are no FDA approved therapies for these tumors and their relentless progression results in high rates of morbidity and mortality. Through a combination of high throughput screens, preclinical in vivo modeling, and evaluation of the kinome en masse, we identified actionable drug targets and efficacious experimental therapeutics for the treatment of NF2 related schwannomas and meningiomas. These efforts identified brigatinib (ALUNBRIG®), an FDA-approved inhibitor of multiple tyrosine kinases including ALK, to be a potent inhibitor of tumor growth in established NF2 deficient xenograft meningiomas and a genetically engineered murine model of spontaneous NF2 schwannomas. Surprisingly, neither meningioma nor schwannoma cells express ALK. Instead, we demonstrate that brigatinib inhibited multiple tyrosine kinases, including EphA2, Fer and focal adhesion kinase 1 (FAK1). These data demonstrate the power of the de novo unbiased approach for drug discovery and represents a major step forward in the advancement of therapeutics for the treatment of NF2 related malignancies.


Subject(s)
Meningeal Neoplasms/genetics , Meningioma/genetics , Neurilemmoma/genetics , Neurofibromin 2/deficiency , Neurofibromin 2/genetics , Organophosphorus Compounds/pharmacology , Protein-Tyrosine Kinases/antagonists & inhibitors , Pyrimidines/pharmacology , Cell Proliferation , Humans , Mutation , Neurilemmoma/pathology
14.
NPJ Breast Cancer ; 7(1): 51, 2021 May 12.
Article in English | MEDLINE | ID: mdl-33980863

ABSTRACT

Inhibition of the HER2/ERBB2 receptor is a keystone to treating HER2-positive malignancies, particularly breast cancer, but a significant fraction of HER2-positive (HER2+) breast cancers recur or fail to respond. Anti-HER2 monoclonal antibodies, like trastuzumab or pertuzumab, and ATP active site inhibitors like lapatinib, commonly lack durability because of adaptive changes in the tumor leading to resistance. HER2+ cell line responses to inhibition with lapatinib were analyzed by RNAseq and ChIPseq to characterize transcriptional and epigenetic changes. Motif analysis of lapatinib-responsive genomic regions implicated the pioneer transcription factor FOXA1 as a mediator of adaptive responses. Lapatinib in combination with FOXA1 depletion led to dysregulation of enhancers, impaired adaptive upregulation of HER3, and decreased proliferation. HER2-directed therapy using clinically relevant drugs (trastuzumab with or without lapatinib or pertuzumab) in a 7-day clinical trial designed to examine early pharmacodynamic response to antibody-based anti-HER2 therapy showed reduced FOXA1 expression was coincident with decreased HER2 and HER3 levels, decreased proliferation gene signatures, and increased immune gene signatures. This highlights the importance of the immune response to anti-HER2 antibodies and suggests that inhibiting FOXA1-mediated adaptive responses in combination with HER2 targeting is a potential therapeutic strategy.

15.
NPJ Breast Cancer ; 7(1): 40, 2021 Apr 09.
Article in English | MEDLINE | ID: mdl-33837205

ABSTRACT

Dysregulation of PI3K/Akt signaling is a dominant feature in basal-like or triple-negative breast cancers (TNBC). However, the mechanisms regulating this pathway are largely unknown in this subset of aggressive tumors. Here we demonstrate that the transcription factor SOX4 is a key regulator of PI3K signaling in TNBC. Genomic and proteomic analyses coupled with mechanistic studies identified TGFBR2 as a direct transcriptional target of SOX4 and demonstrated that TGFBR2 is required to mediate SOX4-dependent PI3K signaling. We further report that SOX4 and the SWI/SNF ATPase SMARCA4, which are uniformly overexpressed in basal-like tumors, form a previously unreported complex that is required to maintain an open chromatin conformation at the TGFBR2 regulatory regions in order to mediate TGFBR2 expression and PI3K signaling. Collectively, our findings delineate the mechanism by which SOX4 and SMARCA4 cooperatively regulate PI3K/Akt signaling and suggest that this complex may play an essential role in TNBC genesis and/or progression.

16.
Nat Med ; 27(1): 165-173, 2021 01.
Article in English | MEDLINE | ID: mdl-33442015

ABSTRACT

Neurofibromatosis type 1 (NF1) plexiform neurofibromas (PNs) are progressive, multicellular neoplasms that cause morbidity and may transform to sarcoma. Treatment of Nf1fl/fl;Postn-Cre mice with cabozantinib, an inhibitor of multiple tyrosine kinases, caused a reduction in PN size and number and differential modulation of kinases in cell lineages that drive PN growth. Based on these findings, the Neurofibromatosis Clinical Trials Consortium conducted a phase II, open-label, nonrandomized Simon two-stage study to assess the safety, efficacy and biologic activity of cabozantinib in patients ≥16 years of age with NF1 and progressive or symptomatic, inoperable PN ( NCT02101736 ). The trial met its primary outcome, defined as ≥25% of patients achieving a partial response (PR, defined as ≥20% reduction in target lesion volume as assessed by magnetic resonance imaging (MRI)) after 12 cycles of therapy. Secondary outcomes included adverse events (AEs), patient-reported outcomes (PROs) assessing pain and quality of life (QOL), pharmacokinetics (PK) and the levels of circulating endothelial cells and cytokines. Eight of 19 evaluable (42%) trial participants achieved a PR. The median change in tumor volume was 15.2% (range, +2.2% to -36.9%), and no patients had disease progression while on treatment. Nine patients required dose reduction or discontinuation of therapy due to AEs; common AEs included gastrointestinal toxicity, hypothyroidism, fatigue and palmar plantar erythrodysesthesia. A total of 11 grade 3 AEs occurred in eight patients. Patients with PR had a significant reduction in tumor pain intensity and pain interference in daily life but no change in global QOL scores. These data indicate that cabozantinib is active in NF1-associated PN, resulting in tumor volume reduction and pain improvement.


Subject(s)
Anilides/therapeutic use , Neurofibroma, Plexiform/drug therapy , Neurofibromatosis 1/drug therapy , Pyridines/therapeutic use , Adolescent , Adult , Anilides/adverse effects , Anilides/pharmacokinetics , Animals , Disease Models, Animal , Female , Genes, Neurofibromatosis 1 , Humans , Male , Mice , Mice, Mutant Strains , Neurofibroma, Plexiform/genetics , Neurofibroma, Plexiform/pathology , Neurofibromatosis 1/genetics , Neurofibromatosis 1/pathology , Pain Measurement , Prospective Studies , Protein Kinase Inhibitors/adverse effects , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/therapeutic use , Pyridines/adverse effects , Pyridines/pharmacokinetics , Quality of Life , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Translational Research, Biomedical , Young Adult
17.
Mol Cancer Ther ; 19(11): 2382-2395, 2020 11.
Article in English | MEDLINE | ID: mdl-32847978

ABSTRACT

Loss of the tumor suppressor NF1 leads to activation of RAS effector pathways, which are therapeutically targeted by inhibition of mTOR (mTORi) or MEK (MEKi). However, therapeutic inhibition of RAS effectors leads to the development of drug resistance and ultimately disease progression. To investigate molecular signatures in the context of NF1 loss and subsequent acquired drug resistance, we analyzed the exomes, transcriptomes, and kinomes of Nf1-mutant mouse tumor cell lines and derivatives of these lines that acquired resistance to either MEKi or mTORi. Biochemical comparisons of this unique panel of tumor cells, all of which arose in Nf1+/- mice, indicate that loss of heterozygosity of Nf1 as an initial genetic event does not confer a common biochemical signature or response to kinase inhibition. Although acquired drug resistance by Nf1-mutant tumor cells was accompanied by altered kinomes and irreversibly altered transcriptomes, functionally in multiple Nf1-mutant tumor cell lines, MEKi resistance was a stable phenotype, in contrast to mTORi resistance, which was reversible. Collectively, these findings demonstrate that Nf1-mutant tumors represent a heterogeneous group biochemically and undergo broader remodeling of kinome activity and gene expression in response to targeted kinase inhibition.


Subject(s)
Mutation , Neurofibromatosis 1/genetics , Neurofibromatosis 1/metabolism , Neurofibromin 1/genetics , Protein Kinases/metabolism , Transcriptome , Animals , Cell Line, Tumor , Computational Biology , Disease Models, Animal , Drug Resistance, Neoplasm/drug effects , Gene Expression Profiling , High-Throughput Nucleotide Sequencing , Humans , Mice , Models, Biological , Neurofibromatosis 1/drug therapy , Neurofibromatosis 1/pathology , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Signal Transduction
18.
Genet Med ; 22(11): 1786-1793, 2020 11.
Article in English | MEDLINE | ID: mdl-32601387

ABSTRACT

PURPOSE: Plexiform neurofibromas (pNF) develop in children with neurofibromatosis type 1 (NF1) and can be associated with several skeletal comorbidities. Preclinical mouse studies revealed Nf1 deficiency in osteoprogenitor cells disrupts, in a MEK-dependent manner, pyrophosphate (PPi) homeostasis and skeletal mineralization. The etiology of NF-associated skeletal manifestations remains unknown. METHODS: We used mouse models of NF1 neurofibromas to assess bone mineralization of skeletal structures adjacent to tumors. Expression of genes involved in pyrophosphate homeostasis was assessed in mouse and human NF tumors and Schwann cell cultures. We used dual-energy X-ray absorptiometry (DXA) to assess tumor-associated changes in bone mineral density (BMD) in an individual with NF1 following treatment with the MEK inhibitor selumetinib. RESULTS: We detected increased nonmineralized bone surfaces adjacent to tumors in mouse models of NF1 neurofibromas. Expression of Enpp1, a PPi-generating ectophosphatase, and ANKH, a PPi transporter, was increased in mouse and human neurofibroma-derived tissues and Schwann cells, respectively. In one patient, tumor-associated reductions in BMD were partially rescued following therapy with selumetinib. CONCLUSION: Results indicate that NF-associated skeletal pathologies in NF1 are associated with dysregulated pyrophosphate homeostasis in adjacent NF tumors and suggest that treatment of NFs with MEK inhibitors may improve skeletal manifestations of the disease.


Subject(s)
Neurofibroma, Plexiform , Neurofibroma , Neurofibromatosis 1 , Animals , Humans , Mice , Neurofibroma, Plexiform/genetics , Neurofibromatosis 1/genetics , Protein Kinase Inhibitors , Schwann Cells
19.
Acad Med ; 95(4): 582-589, 2020 04.
Article in English | MEDLINE | ID: mdl-31725465

ABSTRACT

PURPOSE: To examine internal medicine residency program directors' (PDs') screening practices and perceptions about current recruitment challenges. METHOD: In March-May 2017, the Association of Program Directors in Internal Medicine Survey Committee sent a survey to 373 Alliance for Academic Internal Medicine member residency programs. PDs rated the importance of 23 inclusion and 11 exclusion criteria for interview invitation decision making, provided United States Medical Licensing Examination (USMLE) cutoff scores for U.S. medical school and international medical graduates, and indicated changes in recruitment practices due to application inflation, including their ability to conduct holistic review and interest in potential solutions to address application inflation. Exploratory factor analysis was used to identify and confirm factors that were most important to interview invitation decision making. RESULTS: The response rate for eligible programs was 64% (233/363). USMLE Step 2 Clinical Knowledge scores were the criteria most frequently reported to be "very important" (131/233, 57%). Among respondents who reported any criteria as "very important," 155/222 (70%) identified a single most important (SMI) criterion. Non-USMLE criteria were frequently reported as an SMI criterion (68%). Concerning exclusion criteria, 157/231 (68%) reported they "absolutely would not invite" applicants with hints of unprofessional behavior. Of the 214/232 (92%) who reported an increase in applications, 138 (64%) adjusted recruitment practices. Respondents were most interested in limiting the number of applications per applicant (163/231, 71%), allowing applicants to indicate high interest in a subset of programs (151/229, 66%), and creating a national database of qualities of matched applicants for each program (121/228, 53%). CONCLUSIONS: PDs rely heavily on USMLE scores when making interview invitation decisions. However, collectively, non-USMLE criteria were more frequently reported as an SMI criterion. Most programs adjusted recruitment practices to respond to application volume. Several potential solutions to address application inflation garnered wide support.


Subject(s)
Clinical Competence , Decision Making , Education, Medical, Graduate , Internal Medicine/education , School Admission Criteria , Humans , Interviews as Topic , Licensure, Medical , Personnel Selection , Surveys and Questionnaires , United States
20.
J Grad Med Educ ; 11(6): 698-703, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31871572

ABSTRACT

BACKGROUND: Over the past decade, the number of residency applications has increased substantially, causing many residency programs to change their recruitment practices. OBJECTIVE: We determined how internal medicine (IM) residency programs have responded to increased applications by program type (community-based, community-based/university-affiliated, and university-based) and characteristics (percentage of international medical graduates, program size, and program director [PD] tenure). METHODS: The Association of Program Directors in Internal Medicine conducted a national survey of 363 IM PDs in 2017. Five questions assessed IM program responses to the increased number of residency applications in 3 areas: changes in recruitment strategies, impact on ability to perform holistic review, and interest in 5 potential solutions. We performed a subgroup analysis to measure differences by program type and characteristics. RESULTS: The response rate was 64% (233 of 363). There were no differences by program type or characteristics for experiencing an increase in the number of applicants, altering recruitment practices, or conducting holistic reviews. There were moderate differences in alterations of recruitment practices by program characteristics and moderate differences in interest in proposed solutions by program type. Community-based programs had the greatest interest in a program-specific statement (59%, P = .032) and the lowest percentage in a national database of matched applicants (44%, P = .034). CONCLUSIONS: IM residency programs are experiencing an increasing number of applications and are accommodating by adjusting recruitment practices in a variety of ways. A majority of IM PDs supported 4 of the 5 solutions, although the level of interest differed by program type.


Subject(s)
Education, Medical, Graduate/organization & administration , Internal Medicine/organization & administration , Internship and Residency/organization & administration , Community Medicine , Foreign Medical Graduates , Humans , Internal Medicine/education , Personnel Selection/methods , Surveys and Questionnaires , United States
SELECTION OF CITATIONS
SEARCH DETAIL
...