9 results on '"Hewitt AM"'
Search Results
2. Genome-scale clustered regularly interspaced short palindromic repeats screen identifies nucleotide metabolism as an actionable therapeutic vulnerability in diffuse large B-cell lymphoma.
- Author
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Davies N, Francis T, Oldreive C, Azam M, Wilson J, Byrd PJ, Burley M, Sharma-Oates A, Keane P, Alatawi S, Higgs MR, Rudzki Z, Ibrahim M, Perry T, Agathanggelou A, Hewitt AM, Smith E, Bonifer C, O'Connor M, Forment JV, Murray PG, Fennell E, Kelly G, Chang C, Stewart GS, Stankovic T, Kwok M, and Taylor AM
- Abstract
Diffuse large B-cell lymphoma (DLBCL) is the most common malignancy that develops in patients with ataxia-telangiectasia, a cancer-predisposing inherited syndrome characterized by inactivating germline ATM mutations. ATM is also frequently mutated in sporadic DLBCL. To investigate lymphomagenic mechanisms and lymphoma-specific dependencies underlying defective ATM, we applied ribonucleic acid (RNA)-seq and genome-scale loss-offunction clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 screens to systematically interrogate B-cell lymphomas arising in a novel murine model (Atm-/-nu-/-) with constitutional Atm loss, thymic aplasia but residual T-cell populations. Atm-/-nu-/-lymphomas, which phenotypically resemble either activated B-cell-like or germinal center Bcell-like DLBCL, harbor a complex karyotype, and are characterized by MYC pathway activation. In Atm-/-nu-/-lymphomas, we discovered nucleotide biosynthesis as a MYCdependent cellular vulnerability that can be targeted through the synergistic nucleotidedepleting actions of mycophenolate mofetil (MMF) and the WEE1 inhibitor, adavosertib (AZD1775). The latter is mediated through a synthetically lethal interaction between RRM2 suppression and MYC dysregulation that results in replication stress overload in Atm-/-nu-/-lymphoma cells. Validation in cell line models of human DLBCL confirmed the broad applicability of nucleotide depletion as a therapeutic strategy for MYC-driven DLBCL independent of ATM mutation status. Our findings extend current understanding of lymphomagenic mechanisms underpinning ATM loss and highlight nucleotide metabolism as a targetable therapeutic vulnerability in MYC-driven DLBCL.
- Published
- 2024
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3. The Alaska Native/American Indian experience of hepatitis C treatment with sofosbuvir-based direct-acting antivirals.
- Author
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Townshend-Bulson L, Roik E, Barbour Y, Bruden DJT, Homan CE, Espera HGF, Stevenson TJ, Hewitt AM, Rhodes W, Gove JE, Plotnik JN, Snowball MM, McGilvray J, Simons BC, Johnston JM, and McMahon BJ
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- Adult, Aged, Alaska epidemiology, Drug Combinations, Female, Follow-Up Studies, Hepacivirus isolation & purification, Hepatitis C, Chronic epidemiology, Hepatitis C, Chronic virology, Humans, Male, Middle Aged, Prognosis, Sustained Virologic Response, Antiviral Agents therapeutic use, Benzimidazoles therapeutic use, Carbamates therapeutic use, Fluorenes therapeutic use, Hepacivirus drug effects, Hepatitis C, Chronic drug therapy, Heterocyclic Compounds, 4 or More Rings therapeutic use, Sofosbuvir therapeutic use, American Indian or Alaska Native statistics & numerical data
- Abstract
Background: Direct-acting antiviral (DAA) drugs have been effective in the treatment of chronic hepatitis C virus (HCV) infection. Limited data are available on safety, tolerability, and efficacy in American Indian or Alaska Native people. We aim to evaluate the treatment outcomes of sofosbuvir- based regimens for treatment of HCV in a real life setting in Alaska Native/American Indian (AN/AI) people., Methods: AN/AI patients within the Alaska Tribal Health System with confirmed positive anti-HCV and HCV RNA, who were 18 years of age and older were included in the study. Pretreatment baseline patient characteristics, treatment efficacy based on sustained virologic response (SVR) 12 weeks after treatment completion, and adverse effects were assessed. The following treatments were given according to the American Association for the Study of Liver Diseases/Infectious Disease Society of America (AASLD/IDSA) HCV Guidance: ledipasvir/sofosbuvir, sofosbuvir plus weight-based ribavirin, and sofosbuvir/velpatasvir., Results: We included 501 patients with a mean age of 54.3 (range 21.3-78.3) in the study. Overall SVR was achieved in 95.2% of patients who received one of the three DAA regimens. For those with cirrhosis, overall SVR was 92.8% and for those with genotype 3 91.1% achieved SVR. The most common symptom experienced during treatment was headache. Joint pain was found to decrease during treatment. One person discontinued sofosbuvir plus ribavirin due to myocardial infarction and one discontinued sofosbuvir/velpatasvir due to urticaria., Conclusions: In the real-world setting, sofosbuvir-based treatment is safe, effective, and well tolerated in AN/AI patients. Sustained virologic response was high regardless of HCV genotype or cirrhosis status., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
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4. Observed Changes in Natural Killer and T cell Phenotypes with Evaluation of Immune Outcome in a Longitudinal Cohort Following Sofosbuvir -Based Therapy for Chronic Hepatitis C Infection.
- Author
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Stevenson TJ, Barbour Y, McMahon BJ, Townshend-Bulson L, Hewitt AM, Espera HGF, Homan C, Holck P, Luna SV, Knall C, and Simons BC
- Abstract
Background: Chronic hepatitis C virus (HCV) infection diminishes immune function through cell exhaustion and repertoire alteration. Direct acting antiviral (DAA)-based therapy can restore immune cell subset function and reduce exhaustion states. However, the extent of immune modulation following DAA-based therapy and the role that clinical and demographic factors play remain unknown., Methods: We examined natural killer (NK) cell, CD4
+ , and CD8+ T cell subsets along with activation and exhaustion phenotypes across an observational study of sofosbuvir -based treatment for chronic HCV infection. Additionally, we examined the ability of clinical variables and duration of infection to predict 12 weeks of sustained virologic response (SVR12) immune marker outcomes., Results: We show that sofosbuvir -based therapy restores NK cell subset distributions and reduces chronic activation by SVR12. Likewise, T cell subsets, including HCV-specific CD8+ T cells, show reductions in chronic exhaustion markers by SVR12. Immunosuppressive CD4+ regulatory T cells decrease at 4-weeks treatment and SVR12. We observe the magnitude and direction of change in immune marker values from pretreatment to SVR12 varies greatly among participants. Although we observed associations between the estimated date of infection, HCV diagnosis date, and extent of immune marker outcome at SVR12, our regression analyses did not indicate any factors as strong SVR12 outcome predictors., Conclusion: Our study lends further evidence of immune changes following sofosbuvir -based therapy. Further investigation beyond SVR12 and into factors that may predict posttreatment outcome is warranted.- Published
- 2019
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5. Estrogen Activation by Steroid Sulfatase Increases Colorectal Cancer Proliferation via GPER.
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Gilligan LC, Rahman HP, Hewitt AM, Sitch AJ, Gondal A, Arvaniti A, Taylor AE, Read ML, Morton DG, and Foster PA
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- Activation, Metabolic drug effects, Animals, Antimetabolites pharmacology, Bromodeoxyuridine pharmacology, Cell Line, Cell Proliferation drug effects, Cells, Cultured, Female, Humans, Male, Mice, Mice, Nude, Middle Aged, RNA, Small Interfering genetics, Signal Transduction genetics, Xenograft Model Antitumor Assays, Colorectal Neoplasms pathology, Estrogens metabolism, Receptors, Estrogen metabolism, Receptors, G-Protein-Coupled metabolism, Steryl-Sulfatase pharmacology
- Abstract
Context: Estrogens affect the incidence and progression of colorectal cancer (CRC), although the precise molecular mechanisms remain ill-defined., Objective: The present study investigated prereceptor estrogen metabolism through steroid sulphatase (STS) and 17β-hydroxysteroid dehydrogenase activity and subsequent nongenomic estrogen signaling in human CRC tissue, in The Cancer Genome Atlas colon adenocarcinoma data set, and in in vitro and in vivo CRC models. We aimed to define and therapeutically target pathways through which estrogens alter CRC proliferation and progression., Design, Setting, Patients, and Interventions: Human CRC samples with normal tissue-matched controls were collected from postmenopausal female and age-matched male patients. Estrogen metabolism enzymes and nongenomic downstream signaling pathways were determined. CRC cell lines were transfected with STS and cultured for in vitro and in vivo analysis. Estrogen metabolism was determined using an ultra-performance liquid chromatography-tandem mass spectrometry method., Primary Outcome Measure: The proliferative effects of estrogen metabolism were evaluated using 5-bromo-2'-deoxyuridine assays and CRC mouse xenograft studies., Results: Human CRC exhibits dysregulated estrogen metabolism, favoring estradiol synthesis. The activity of STS, the fundamental enzyme that activates conjugated estrogens, is significantly (P < 0.001) elevated in human CRC compared with matched controls. STS overexpression accelerates CRC proliferation in in vitro and in vivo models, with STS inhibition an effective treatment. We defined a G-protein-coupled estrogen receptor (GPER) proproliferative pathway potentially through increased expression of connective tissue growth factor in CRC., Conclusion: Human CRC favors estradiol synthesis to augment proliferation via GPER stimulation. Further research is required regarding whether estrogen replacement therapy should be used with caution in patients at high risk of developing CRC., (Copyright © 2017 Endocrine Society)
- Published
- 2017
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6. Estrone Sulfate Transport and Steroid Sulfatase Activity in Colorectal Cancer: Implications for Hormone Replacement Therapy.
- Author
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Gilligan LC, Gondal A, Tang V, Hussain MT, Arvaniti A, Hewitt AM, and Foster PA
- Abstract
Hormone replacement therapy (HRT) affects the incidence and potential progression of colorectal cancer (CRC). As HRT primarily consists of estrone sulfate (E
1 S), understanding whether this conjugated estrogen is transported and metabolized in CRC will define its potential effect in this malignancy. Here, we show that a panel of CRC cell lines (Colo205, Caco2, HCT116, HT-29) have steroid sulfatase (STS) activity, and thus can hydrolyze E1 S. STS activity is significantly higher in CRC cell lysate, suggesting the importance of E1 S transport in intracellular STS substrate availability. As E1 S transport is regulated by the expression pattern of certain solute carrier organic anion transporter polypeptides, we show that in CRC OATP4A1 is the most abundantly expressed transporter. All four CRC cell lines rapidly transported E1 S into cells, with this effect significantly inhibited by the competitive OATP inhibitor BSP. Transient knockdown of OATP4A1 significantly disrupted E1 S uptake. Examination of estrogen receptor status showed ERα was present in Colo205 and Caco2 cells. None of the cells expressed ERβ. Intriguingly, HCT116 and HT29 cells strongly expressed the G protein coupled estrogen receptor (GPER), and that stimulation of this receptor with estradiol (E2 ) and G1, a GPER agonist, significantly ( p < 0.01) increased STS activity. Furthermore, tamoxifen and fulvestrant, known GPER agonist, also increased CRC STS activity, with this effect inhibited by the GPER antagonist G15. These results suggest that CRC can take up and hydrolyze E1 S, and that subsequent GPER stimulation increases STS activity in a potentially novel positive feedback loop. As elevated STS expression is associated with poor prognosis in CRC, these results suggest HRT, tamoxifen and fulvestrant may negatively impact CRC patient outcomes.- Published
- 2017
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7. Rapid identification of novel functional promoters for gene therapy.
- Author
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Pringle IA, Gill DR, Connolly MM, Lawton AE, Hewitt AM, Nunez-Alonso G, Cheng SH, Scheule RK, Davies LA, and Hyde SC
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- Genetic Vectors genetics, Transgenes genetics, Genetic Therapy methods, Promoter Regions, Genetic genetics
- Abstract
Transcriptional control of transgene expression is crucial to successful gene therapy, yet few promoter/enhancer combinations have been tested in clinical trials. We created a simple, desktop computer database and populated it with promoter sequences from publicly available sources. From this database, we rapidly identified novel CpG-free promoter sequences suitable for use in non-inflammatory, non-viral in vivo gene transfer. In a simple model of lung gene transfer, five of the six promoter elements selected, chosen without prior knowledge of their transcriptional activities, directed significant transgene expression. Each of the five novel promoters directed transgene expression for at least 14 days post-delivery, greatly exceeding the duration achieved with the commonly used CpG-rich viral enhancer/promoters. Novel promoter activity was also evaluated in a more clinically relevant model of aerosol-mediated lung gene transfer and in the liver following delivery via high-pressure tail vein injection. In each case, the novel CpG-free promoters exhibited higher and/or more sustained transgene expression than commonly used CpG-rich enhancer/promoter sequences. This study demonstrates that novel CpG-free promoters can be readily identified and that they can direct significant levels of transgene expression. Furthermore, the database search criteria can be quickly adjusted to identify other novel promoter elements for a variety of transgene expression applications.
- Published
- 2012
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8. Adoption of an algorithm and client pathway for the aged and disabled: training implications for the health and human service sectors.
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Hewitt AM, Polansky PA, Day N, Field N, and Moore A
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- Aged, Humans, New Jersey, Algorithms, Disabled Persons, Health Personnel education
- Abstract
Objectives: This paper reports on a state agency's training activities undertaken to totally redesign a long-term-care (LTC) delivery system as part of the national Aging and Disability Resource Center (ADRC) initiative., Method: Through the development of an ADRC algorithm and the implementation of a corresponding client pathway, NJ DACS, a division of aging, aligned 14 separate core functions necessary for lifespan services. A Training Academy facilitated the adoption of five new health service delivery products and processes by state and county health and human services personnel., Results: Intensive training activities resulted in the algorithm and client pathway framework being successfully disseminated in all 21 counties within a short timeframe. Barriers to training were reduced and acceptance of new protocols and processes were facilitated leading to rapid adoption. Implications for training of health and human service personnel are presented. Full adoption of the complete ADRC model across the state was directly linked to agency software integration., Conclusions: Promoting standardized service delivery for the aging population through the use of an algorithm and parallel client pathway is feasible as a training model for health care service delivery.
- Published
- 2011
9. Antiemesis after total joint arthroplasty: does a single preoperative dose of aprepitant reduce nausea and vomiting?
- Author
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DiIorio TM, Sharkey PF, Hewitt AM, and Parvizi J
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- Adult, Aged, Aged, 80 and over, Antiemetics adverse effects, Aprepitant, Case-Control Studies, Drug Administration Schedule, Female, Humans, Length of Stay, Male, Middle Aged, Morpholines adverse effects, Ondansetron administration & dosage, Preoperative Care, Retrospective Studies, Severity of Illness Index, Time Factors, Treatment Outcome, Antiemetics administration & dosage, Arthroplasty, Replacement, Hip adverse effects, Arthroplasty, Replacement, Knee adverse effects, Morpholines administration & dosage, Postoperative Nausea and Vomiting prevention & control
- Abstract
Background: Postoperative nausea and vomiting (PONV) is frequent after joint arthroplasty; in addition to causing patient distress, it interferes with early mobilization and hospital discharge. Various antiemetic agents reduce PONV, but their action is limited by a short half-life. Aprepitant, an antiemetic developed for patients receiving chemotherapy, has a duration of action much longer than other antiemetics., Questions/purposes: We asked whether a single dose of preoperative aprepitant (40 mg orally) reduced postoperative nausea and vomiting after THA or TKA., Methods: Fifty patients who received a preoperative dose of aprepitant (study group) were matched demographically to 50 patients who did not receive aprepitant (control group) from a group of patients undergoing THA or TKA. Patients' charts were reviewed to identify episodes of PONV, number of doses of antiemetics needed for breakthrough PONV, and length of stay. Aprepitant side effects, and complications., Results: Aprepitant reduced the percentage of patients with PONV (39% of study and 70% of control patients). Moderate or severe PONV occurred in 22% of study and 40% of control patients. The number of episodes of PONV during hospitalization was 2.9 for the control group and 1.6 for the study group. Postoperatively, the control group required on average 1.3 doses of ondansetron compared with 0.6 doses for the study group. Hospital length of stay was reduced from 3.3 days for the control group and to 2.3 days for the study group., Conclusions: These data suggest a single preoperative dose of aprepitant reduces the number of episodes and severity of PONV, the need for additional antiemetics, and the length of stay., Level of Evidence: Level II, prognostic study. See guidelines for authors for a complete description of levels of evidence.
- Published
- 2010
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