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Trněný M, Avigdor A, McKinney MS, Paneesha S, Wahlin BE, Hrom JS, Cunningham D, Morley N, Canales M, Bastos-Oreiro M, Belada D, Devizzi L, Zheng F, DeMarini DJ, Jiang W, Jiang P, Lynch RC. Parsaclisib, a PI3Kδ inhibitor, in relapsed and refractory follicular lymphoma (CITADEL-203): a phase 2 study. EClinicalMedicine 2023; 63:102130. [PMID: 37662520 PMCID: PMC10469382 DOI: 10.1016/j.eclinm.2023.102130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/06/2023] [Accepted: 07/17/2023] [Indexed: 09/05/2023] Open
Abstract
Background Parsaclisib, a potent and highly selective PI3Kδ inhibitor, has shown clinical benefit in patients with relapsed or refractory (R/R) B-cell malignancies. This phase 2 study (CITADEL-203; NCT03126019, EudraCT 2017-001624-22) assessed efficacy and safety of parsaclisib monotherapy in patients with R/R follicular lymphoma (FL). Methods Patients ≥18 years of age with histologically confirmed R/R FL (grade 1-3a) and prior treatment with ≥2 systemic therapies received parsaclisib 20 mg once daily (QD) for 8 weeks then parsaclisib 20 mg once weekly (weekly dosing group [WG]) or parsaclisib 20 mg QD for 8 weeks then parsaclisib 2.5 mg QD (daily dosing group [DG]); DG was selected for further assessment. Primary endpoint was objective response rate (ORR). Findings At data cut-off (January 15, 2021), 126 patients had been treated (WG: n = 23; DG: n = 103). ORR (95% confidence interval [CI]) was 77.7% (68.4-85.3) with a complete response rate (95% CI) of 19.4% (12.3-28.4) in DG; median (95% CI) duration of response was 14.7 months (10.4-not estimable [NE]), median progression-free survival was 15.8 months (11.0-NE), and median overall survival was not reached. The most common any-grade treatment-emergent adverse events (TEAEs) among all treated patients included diarrhoea (n = 48, 38.1%), nausea (n = 31, 24.6%), and cough (n = 28, 22.2%); the most common grade ≥3 TEAEs were diarrhoea (n = 15, 11.9%), neutropenia (n = 13, 10.3%), and colitis (n = 7, 5.6%). Dose interruption, reduction, and discontinuation from TEAEs occurred in 46.8% (n = 59), 17.5% (n = 22), and 23.8% (n = 30) of patients, respectively. Interpretation Treatment with parsaclisib demonstrated rapid and durable responses, and a manageable safety profile in patients with R/R FL. Funding Incyte Corporation.
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Affiliation(s)
- Marek Trněný
- First Department of Medicine – Hematology, Charles University General Hospital, Prague, Czech Republic
| | - Abraham Avigdor
- Institute of Hematology, Sheba Medical Center, Ramat Gan, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Matthew S. McKinney
- Division of Hematologic Malignancies and Cellular Therapy, Department of Medicine, Duke Cancer Institute, Durham, NC, USA
| | - Shankara Paneesha
- Department of Haematology & Stem Cell Transplantation, Birmingham Heartlands Hospital, Birmingham, UK
| | - Björn E. Wahlin
- Karolinska Institutet, Department of Medicine, Huddinge, and Karolinska University Hospital, Unit for Hematology, Stockholm, Sweden
| | - John S. Hrom
- Forrest General Hospital and Hattiesburg Clinic of Hematology and Oncology, Hattiesburg, MS, USA
| | - David Cunningham
- Royal Marsden Hospital, NHS Foundation Trust, London and Surrey, UK
| | - Nicholas Morley
- Sheffield Teaching Hospital, NHS Foundation Trust, Sheffield and London, UK
| | | | - Mariana Bastos-Oreiro
- Hematology Department, Hospital General Universitario Gregorio Marañón (IiSGM), Madrid, Spain
| | - David Belada
- Fourth Department of Internal Medicine – Hematology, Charles University, Hospital and Faculty of Medicine, Hradec Králové, Czech Republic
| | - Liliana Devizzi
- Division of Hemathology and Stem Cell Transplantation, IRCCS Istituto Nazionale Tumori, Milan, Italy
| | | | | | - Wei Jiang
- Incyte Corporation, Wilmington, DE, USA
| | | | - Ryan C. Lynch
- University of Washington School of Medicine, Fred Hutch Cancer Center, Seattle, WA, USA
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Zinzani PL, Trněný M, Ribrag V, Zilioli VR, Walewski J, Christensen JH, Delwail V, Rodriguez G, Venugopal P, Coleman M, Dartigeas C, Patti C, Pane F, Jurczak W, Taszner M, Paneesha S, Zheng F, DeMarini DJ, Jiang W, Gilmartin A, Mehta A. Parsaclisib, a PI3Kδ inhibitor, in relapsed and refractory mantle cell lymphoma (CITADEL-205): a phase 2 study. EClinicalMedicine 2023; 62:102131. [PMID: 37599908 PMCID: PMC10433033 DOI: 10.1016/j.eclinm.2023.102131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Background Parsaclisib is a potent and highly selective PI3Kδ inhibitor that has shown clinical benefit in patients with relapsed/refractory (R/R) B-cell malignancies. In this phase 2 study (CITADEL-205; NCT03235544, EudraCT 2017-003148-19), the efficacy and safety of parsaclisib was evaluated in patients with R/R mantle cell lymphoma (MCL). Methods Patients ≥18 years old with pathologically confirmed R/R MCL and prior treatment with 1-3 systemic therapies, with (cohort 1) or without (cohort 2) previous Bruton kinase inhibitor (BTKi) treatment, received oral parsaclisib 20 mg once-daily (QD) for 8 weeks, then either parsaclisib 20 mg once-weekly (weekly dosing group [WG]) or parsaclisib 2.5 mg QD (daily dosing group [DG]). The primary endpoint was objective response rate (ORR). Findings At the primary analysis data cutoff on January 15, 2021, 53 patients in cohort 1 (BTKi-experienced) (WG, n = 12; DG: n = 41) and 108 patients in cohort 2 (BTKi-naive) (WG, n = 31; DG: n = 77) had received parsaclisib monotherapy. The BTKi-experienced cohort was closed after an interim analysis demonstrated limited clinical benefit. In the BTKi-naive cohort, the ORR (95% CI) for DG (dosing selected for further study) was 70.1% (58.6%-80.0%), with a complete response rate (95% CI) of 15.6% (8.3%-25.6%) and a median duration of response (95% CI) of 12.1 (9.0-not evaluable) months. Treatment-emergent adverse events (TEAEs) occurred among 90.7% (98/108) of all treated patients in the BTKi-naive cohort. Grade ≥3 TEAEs occurred among 62.0% (67/108) of patients, including diarrhoea (13.9%, 15/108) and neutropenia (8.3%, 9/108). Parsaclisib interruption, reduction, or discontinuation due to TEAEs occurred among 47.2% (51/108), 8.3% (9/108), and 25.0% (27/108) of patients, respectively. Fatal TEAEs were experienced by six patients and determined to be treatment-related in one patient. Interpretation Parsaclisib, a potent, highly selective, PI3Kδ inhibitor demonstrated meaningful clinical benefits and a manageable safety profile (25.0% discontinuation rate, low incidences of individually reported grade ≥3 or serious adverse events) in R/R MCL patients with no prior BTKi therapy. Limited clinical benefit was observed with parsaclisib monotherapy in patients who had previously received BTKi treatment. Future development of PI3K inhibitors for NHL will require further investigation of dose optimisation to improve safety and long-term survival. Funding Incyte Corporation.
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Affiliation(s)
- Pier Luigi Zinzani
- IRCCS Azienda Ospedaliero-Universitaria di Bologna, Istituto di Ematologia “Seràgnoli”, Italy
- Dipartimento di Medicina Specialistica, Diagnostica e Sperimentale, Università di Bologna, Bologna, Italy
| | - Marek Trněný
- Charles University, General Hospital, Prague, Czech Republic
| | | | | | - Jan Walewski
- Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | | | | | | | | | - Morton Coleman
- Clinical Research Alliance/Cornell Medicine, New York, NY, USA
| | | | - Caterina Patti
- Department of Oncohematology Unit, Azienda Ospedali Riuniti Villa Sofia Cervello, Palmero, Italy
| | | | - Wojciech Jurczak
- Maria Sklodowska-Curie National Research Institute of Oncology, Kraków, Poland
| | - Michal Taszner
- Department of Haematology and Transplantology, Faculty of Medicine, Medical University of Gdansk, Gdansk, Poland
| | | | | | | | - Wei Jiang
- Incyte Corporation, Wilmington, DE, USA
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Coleman M, Belada D, Casasnovas RO, Gressin R, Lee HP, Mehta A, Munoz J, Verhoef G, Corrado C, DeMarini DJ, Zhao W, Li J, Fay K. Phase 2 study of parsaclisib (INCB050465), a highly selective, next-generation PI3Kδ inhibitor, in relapsed or refractory diffuse large B-cell lymphoma (CITADEL-202). Leuk Lymphoma 2020; 62:368-376. [PMID: 33140664 DOI: 10.1080/10428194.2020.1832660] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Parsaclisib, a potent, highly selective, next-generation PI3Kδ inhibitor, was evaluated as monotherapy in CITADEL-202 (NCT02998476), an open-label, multicenter, phase 2 study in patients with relapsed or refractory diffuse large B-cell lymphoma. Patients enrolled into 2 groups (A, Bruton tyrosine kinase [BTK] inhibitor naïve, n = 55; B, BTK inhibitor experienced, n = 5) received oral parsaclisib 20 mg once daily for 8 weeks, then 20 mg once weekly while deriving benefit. The futility boundary was crossed at the interim analysis of Group A, resulting in a negative study. Parsaclisib monotherapy demonstrated an objective response rate (ORR) of 25.5% (8 complete metabolic responses/6 partial metabolic responses) and a median duration of response of 6.2 months. ORR in Group B was 20.0% (1 complete metabolic response). Parsaclisib monotherapy demonstrated manageable toxicities with no new safety signals reported. Further evaluation of parsaclisib in combination with standard therapies and active investigational agents is underway.
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Affiliation(s)
- Morton Coleman
- Clinical Research Alliance/Weill Cornell Medicine, New York, NY, USA
| | - David Belada
- 4th Department of Internal Medicine - Haematology, Charles University, Hospital and Faculty of Medicine, Hradec Králové, Czech Republic
| | | | - Rémy Gressin
- Department of Oncohaematology, University Hospital Grenoble-Alpes, Grenoble, France.,Institute for Advanced Biosciences, Inserm U 823, Grenoble, France
| | - Hui-Peng Lee
- Flinders Medical Centre, Bedford Park, SA, Australia
| | | | - Javier Munoz
- Banner MD Anderson Cancer Center, Gilbert, AZ, USA
| | - Gregor Verhoef
- Department of Hematology, University Hospitals Leuven, Leuven, Belgium
| | | | | | | | - Jia Li
- Incyte Corporation, Wilmington, DE, USA
| | - Keith Fay
- Department of Haematology, St Vincent's Hospital, Darlinghurst, NSW, Australia
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Ouellet D, Kassir N, Chiu J, Mouksassi MS, Leonowens C, Cox D, DeMarini DJ, Gardner O, Crist W, Patel K. Population pharmacokinetics and exposure-response of trametinib, a MEK inhibitor, in patients with BRAF V600 mutation-positive melanoma. Cancer Chemother Pharmacol 2016; 77:807-17. [PMID: 26940938 DOI: 10.1007/s00280-016-2993-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 02/15/2016] [Indexed: 11/30/2022]
Abstract
PURPOSE To characterize the pharmacokinetics of oral trametinib, a first in class MEK inhibitor, identify covariates, and describe the relationship between exposure and clinical effects in patients with BRAF V600 metastatic melanoma. EXPERIMENTAL DESIGN Trametinib concentrations obtained in three clinical studies were included in the population pharmacokinetic analysis. Trametinib 2 mg once daily was administered in the Phase 2 and 3 studies. The impact of exposure [trough (C min) or average concentration] on response rates and progression-free survival (PFS) was examined. RESULTS Plasma concentrations (n = 3120) obtained in 493 patients were described using a two-compartment model. Trametinib oral clearance was lower in women relative to men (1.26-fold) and increased with body weight. There was no significant effect of age, mild or moderate renal impairment, or mild hepatic impairment on oral clearance. Between-subject variability was low (24 %). The number of responders was consistent across median exposure range, although tended to be lower at trough concentration <10 ng/mL. Disease stage was found to be a significant predictor of response with a lower response rate in patients with disease stage of M1c. Lactate dehydrogenase was significant in the analysis of PFS. Patients with observed C min above the median had longer PFS than those below median based on Phase 2 study (median 10.6 ng/mL), while the effect of exposure was not statistically significant in the Phase 3 study (median 13.6 ng/mL). CONCLUSIONS No dosage adjustments are required with any of the covariates tested. Clinical efficacy was associated with trametinib trough concentrations greater than 10 ng/mL.
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Affiliation(s)
- Daniele Ouellet
- GlaxoSmithKline, Research Triangle Park, NC, USA. .,Janssen Research & Development, Spring House, PA, USA.
| | | | - Joannellyn Chiu
- GlaxoSmithKline, Research Triangle Park, NC, USA.,Inncelerex,, Jersey City, NJ, USA
| | | | - Cathrine Leonowens
- GlaxoSmithKline, Research Triangle Park, NC, USA.,Genentech, South San Francisco, CA, USA
| | - Donna Cox
- Incyte Corporation, Wilmington, DE, USA.,Teva Pharmaceuticals, Frazer, PA, USA
| | | | - Olivia Gardner
- GlaxoSmithKline, Research Triangle Park, NC, USA.,Janssen Research & Development, Spring House, PA, USA
| | - Wendy Crist
- Janssen Research & Development, Spring House, PA, USA.,Incyte Corporation, Wilmington, DE, USA
| | - Kiran Patel
- Janssen Research & Development, Spring House, PA, USA.,Incyte Corporation, Wilmington, DE, USA
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Long GV, Stroyakovskiy D, Gogas H, Levchenko E, de Braud F, Larkin J, Garbe C, Jouary T, Hauschild A, Grob JJ, Chiarion-Sileni V, Lebbe C, Mandalà M, Millward M, Arance A, Bondarenko I, Haanen JBAG, Hansson J, Utikal J, Ferraresi V, Kovalenko N, Mohr P, Probachai V, Schadendorf D, Nathan P, Robert C, Ribas A, DeMarini DJ, Irani JG, Swann S, Legos JJ, Jin F, Mookerjee B, Flaherty K. Dabrafenib and trametinib versus dabrafenib and placebo for Val600 BRAF-mutant melanoma: a multicentre, double-blind, phase 3 randomised controlled trial. Lancet 2015; 386:444-51. [PMID: 26037941 DOI: 10.1016/s0140-6736(15)60898-4] [Citation(s) in RCA: 958] [Impact Index Per Article: 106.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Previously, a study of ours showed that the combination of dabrafenib and trametinib improves progression-free survival compared with dabrafenib and placebo in patients with BRAF Val600Lys/Glu mutation-positive metastatic melanoma. The study was continued to assess the secondary endpoint of overall survival, which we report in this Article. METHODS We did this double-blind phase 3 study at 113 sites in 14 countries. We enrolled previously untreated patients with BRAF Val600Glu or Val600Lys mutation-positive unresectable stage IIIC or stage IV melanoma. Participants were computer-randomised (1:1) to receive a combination of dabrafenib (150 mg orally twice daily) and trametinib (2 mg orally once daily), or dabrafenib and placebo. The primary endpoint was progression-free survival and overall survival was a secondary endpoint. This study is registered with ClinicalTrials.gov, number NCT01584648. FINDINGS Between May 4, 2012, and Nov 30, 2012, we screened 947 patients for eligibility, of whom 423 were randomly assigned to receive dabrafenib and trametinib (n=211) or dabrafenib only (n=212). The final data cutoff was Jan 12, 2015, at which time 222 patients had died. Median overall survival was 25·1 months (95% CI 19·2-not reached) in the dabrafenib and trametinib group versus 18·7 months (15·2-23·7) in the dabrafenib only group (hazard ratio [HR] 0·71, 95% CI 0·55-0·92; p=0·0107). Overall survival was 74% at 1 year and 51% at 2 years in the dabrafenib and trametinib group versus 68% and 42%, respectively, in the dabrafenib only group. Based on 301 events, median progression-free survival was 11·0 months (95% CI 8·0-13·9) in the dabrafenib and trametinib group and 8·8 months (5·9-9·3) in the dabrafenib only group (HR 0·67, 95% CI 0·53-0·84; p=0·0004; unadjusted for multiple testing). Treatment-related adverse events occurred in 181 (87%) of 209 patients in the dabrafenib and trametinib group and 189 (90%) of 211 patients in the dabrafenib only group; the most common was pyrexia (108 patients, 52%) in the dabrafenib and trametinib group, and hyperkeratosis (70 patients, 33%) in the dabrafenib only group. Grade 3 or 4 adverse events occurred in 67 (32%) patients in the dabrafenib and trametinib group and 66 (31%) patients in the dabrafenib only group. INTERPRETATION The improvement in overall survival establishes the combination of dabrafenib and trametinib as the standard targeted treatment for BRAF Val600 mutation-positive melanoma. Studies assessing dabrafenib and trametinib in combination with immunotherapies are ongoing. FUNDING GlaxoSmithKline.
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Affiliation(s)
- Georgina V Long
- Melanoma Institute Australia, University of Sydney, Sydney, NSW, Australia; Mater Hospital, Sydney, NSW, Australia.
| | | | - Helen Gogas
- Department of Medicine, University of Athens, Medical School, Athens, Greece
| | | | | | | | - Claus Garbe
- Department of Dermatology, University Hospital Tuebingen, Tuebingen, Germany
| | - Thomas Jouary
- Department of Dermatology, Hôpital Saint André, CHU Bordeaux, Bordeaux, France
| | | | - Jean-Jacques Grob
- Aix-Marseille University and APHM Hospital CHU Timone, Marseille, France
| | - Vanna Chiarion-Sileni
- Melanoma and Oesophageal Oncology Unit, Veneto Oncology Institute-IRCCS, Padua, Italy
| | - Celeste Lebbe
- APHP Dermatology CIC Hôpital Saint Louis, University Paris Diderot, INSERM U976, Paris, France
| | - Mario Mandalà
- Papa Giovanni XXIII Cancer Center Hospital, Bergamo, Italy
| | - Michael Millward
- Sir Charles Gairdner Hospital, Hospital Avenue, Perth, WA, Australia
| | - Ana Arance
- Department of Medical Oncology, Hospital Clinic and Translational Genomics and Targeted Therapeutics in Solid Tumors, Barcelona, Spain
| | - Igor Bondarenko
- Dnepropetrovsk State Medical Academy, Dnepropetrovsk, Ukraine
| | | | - Johan Hansson
- Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Jochen Utikal
- University Medical Center Mannheim, Heidelberg University, Mannheim, Germany; German Cancer Research Center, Heidelberg, Germany
| | | | | | | | - Volodymr Probachai
- Dnipropetrovsk Clinical Oncology Center of Dnipropetrovsk State Council, Dnipropetrovsk, Ukraine
| | | | | | - Caroline Robert
- Gustave Roussy, Villejuif-Paris-Sud, France; Paris Sud University, Le Kremlin Bicêtre, France
| | - Antoni Ribas
- David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | | | | | - Suzanne Swann
- Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
| | | | - Fan Jin
- Merck & Co, Kenilworth, NJ, USA
| | | | - Keith Flaherty
- Massachusetts General Hospital Cancer Center, Boston MA, USA
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Schadendorf D, Amonkar MM, Stroyakovskiy D, Levchenko E, Gogas H, de Braud F, Grob JJ, Bondarenko I, Garbe C, Lebbe C, Larkin J, Chiarion-Sileni V, Millward M, Arance A, Mandalà M, Flaherty KT, Nathan P, Ribas A, Robert C, Casey M, DeMarini DJ, Irani JG, Aktan G, Long GV. Health-related quality of life impact in a randomised phase III study of the combination of dabrafenib and trametinib versus dabrafenib monotherapy in patients with BRAF V600 metastatic melanoma. Eur J Cancer 2015; 51:833-40. [PMID: 25794603 DOI: 10.1016/j.ejca.2015.03.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 03/04/2015] [Indexed: 01/23/2023]
Abstract
AIM To present the impact of treatments on health-related quality of life (HRQoL) from the double-blind, randomised phase III COMBI-d study that investigated the combination of dabrafenib and trametinib versus dabrafenib monotherapy in patients with BRAF V600E/K-mutant metastatic melanoma. COMBI-d showed significantly prolonged progression-free survival for the combination. METHODS HRQoL was evaluated using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-C30, a generic cancer questionnaire (completed at baseline, during study treatment, at progression and post progression) assessing various dimensions (global health/QoL, functional status, and symptom impact). A mixed-model, repeated-measures analyses of covariance evaluated differences between arms. RESULTS Questionnaire completion rates were >95% at baseline, >85% to week 40 and >70% at disease progression. Baseline scores across both arms were comparable for all dimensions. Global health dimension scores were significantly better at weeks 8, 16 and 24 for patients receiving the combination during treatment and at progression. The majority of functional dimension scores (physical, social, role, emotional and cognitive functioning) trended in favour of the combination. Pain scores were significantly improved and clinically meaningful (6-13 point difference) for patients receiving the combination for all follow-up assessments versus those receiving dabrafenib monotherapy. For other symptom dimensions (nausea and vomiting, diarrhoea, dyspnoea, and constipation), scores trended in favour of dabrafenib monotherapy. CONCLUSION This analysis demonstrates that the combination of dabrafenib and trametinib provides better preservation of HRQoL and pain improvements versus dabrafenib monotherapy while also delaying progression. (Clinicaltrials.gov registration number: NCT01584648).
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Affiliation(s)
- Dirk Schadendorf
- Universitätsklinikum Essen, Hufelandstr. 55, Essen 45147, Germany.
| | - Mayur M Amonkar
- GlaxoSmithKline, 1250 S Collegeville Rd, Collegeville, PA 19426, United States.
| | | | - Evgeny Levchenko
- Petrov Research Institute of Oncology, 68 Leningradskaya Street, Saint Petersburg 197758, Russia.
| | - Helen Gogas
- University of Athens, Aghiou Thoma 17, Athens 11527, Greece.
| | - Filippo de Braud
- Fondazione IRCCS Istituto Nazionale Tumori, via Giacomo Venezian, 1, Milan, Italy.
| | - Jean-Jacques Grob
- Service de Dermatologie, Centre Hospitalo-Universitaire Sainte-Marguerite, 270 Boulevard de Sainte-Marguerite, Marseille 13009, France.
| | - Igor Bondarenko
- Dnepropetrovsk State Medical Academy, Dzerzhyns'koho Street 9, Dnepropetrovsk 49044, Ukraine.
| | - Claus Garbe
- Department of Dermatology, University Hospital Tuebingen, Liebermeisterstraße 25, Tuebingen 72076, Germany.
| | - Celeste Lebbe
- APHP Dermatology CIC Hôpital Saint Louis, University Paris Diderot, INSERM U976, Avenue Claude Vellefaux, Paris 75010, France.
| | - James Larkin
- Royal Marsden Hospital, Fulham Road, London SW3 6JJ, United Kingdom.
| | - Vanna Chiarion-Sileni
- Melanoma and Esophageal Oncology Unit, Veneto Oncology Institute-IRCCS, via Gattamelata, 64, Padua 35128, Italy.
| | - Michael Millward
- Sir Charles Gairdner Hospital, Hospital Avenue, Perth, WA 6009, Australia.
| | - Ana Arance
- Hospital Clinic, Carrer Villarroel 170, Barcelona 08036, Spain.
| | - Mario Mandalà
- Papa Giovanni XIII Hospital, Piazza OMS 1, Bergamo 24127, Italy.
| | - Keith T Flaherty
- Massachusetts General Hospital Cancer Center, 55 Fruit St, Boston 02114, MA, United States.
| | - Paul Nathan
- Mount Vernon Cancer Centre, Rickmansworth Road, Northwood HA6 2RN, United Kingdom.
| | - Antoni Ribas
- David Geffen School of Medicine, UCLA, 10833 Le Conte Avenue, Los Angeles 90095, CA, United States.
| | - Caroline Robert
- Gustave Roussy and Paris 11 University, 114 Rue Edouard Vaillant, Villejuif-Paris-Sud 94805, France.
| | - Michelle Casey
- GlaxoSmithKline, 1250 S Collegeville Rd, Collegeville, PA 19426, United States.
| | - Douglas J DeMarini
- GlaxoSmithKline, 1250 S Collegeville Rd, Collegeville, PA 19426, United States.
| | - Jhangir G Irani
- GlaxoSmithKline, 1250 S Collegeville Rd, Collegeville, PA 19426, United States.
| | - Gursel Aktan
- GlaxoSmithKline, 1250 S Collegeville Rd, Collegeville, PA 19426, United States.
| | - Georgina V Long
- Melanoma Institute Australia & The University of Sydney, 40 Rocklands Road, Sydney 2060, Australia.
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7
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Long GV, Stroyakovskiy D, Gogas H, Levchenko E, de Braud F, Larkin J, Garbe C, Jouary T, Hauschild A, Grob JJ, Chiarion Sileni V, Lebbe C, Mandalà M, Millward M, Arance A, Bondarenko I, Haanen JBAG, Hansson J, Utikal J, Ferraresi V, Kovalenko N, Mohr P, Probachai V, Schadendorf D, Nathan P, Robert C, Ribas A, DeMarini DJ, Irani JG, Casey M, Ouellet D, Martin AM, Le N, Patel K, Flaherty K. Combined BRAF and MEK inhibition versus BRAF inhibition alone in melanoma. N Engl J Med 2014; 371:1877-88. [PMID: 25265492 DOI: 10.1056/nejmoa1406037] [Citation(s) in RCA: 1278] [Impact Index Per Article: 127.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Combined BRAF and MEK inhibition, as compared with BRAF inhibition alone, delays the emergence of resistance and reduces toxic effects in patients who have melanoma with BRAF V600E or V600K mutations. METHODS In this phase 3 trial, we randomly assigned 423 previously untreated patients who had unresectable stage IIIC or stage IV melanoma with a BRAF V600E or V600K mutation to receive a combination of dabrafenib (150 mg orally twice daily) and trametinib (2 mg orally once daily) or dabrafenib and placebo. The primary end point was progression-free survival. Secondary end points included overall survival, response rate, response duration, and safety. A preplanned interim overall survival analysis was conducted. RESULTS The median progression-free survival was 9.3 months in the dabrafenib-trametinib group and 8.8 months in the dabrafenib-only group (hazard ratio for progression or death in the dabrafenib-trametinib group, 0.75; 95% confidence interval [CI], 0.57 to 0.99; P=0.03). The overall response rate was 67% in the dabrafenib-trametinib group and 51% in the dabrafenib-only group (P=0.002). At 6 months, the interim overall survival rate was 93% with dabrafenib-trametinib and 85% with dabrafenib alone (hazard ratio for death, 0.63; 95% CI, 0.42 to 0.94; P=0.02). However, a specified efficacy-stopping boundary (two-sided P=0.00028) was not crossed. Rates of adverse events were similar in the two groups, although more dose modifications occurred in the dabrafenib-trametinib group. The rate of cutaneous squamous-cell carcinoma was lower in the dabrafenib-trametinib group than in the dabrafenib-only group (2% vs. 9%), whereas pyrexia occurred in more patients (51% vs. 28%) and was more often severe (grade 3, 6% vs. 2%) in the dabrafenib-trametinib group. CONCLUSIONS A combination of dabrafenib and trametinib, as compared with dabrafenib alone, improved the rate of progression-free survival in previously untreated patients who had metastatic melanoma with BRAF V600E or V600K mutations. (Funded by GlaxoSmithKline; Clinical Trials.gov number, NCT01584648.).
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Villanueva J, Infante JR, Krepler C, Reyes-Uribe P, Samanta M, Chen HY, Li B, Swoboda RK, Wilson M, Vultur A, Fukunaba-Kalabis M, Wubbenhorst B, Chen TY, Liu Q, Sproesser K, DeMarini DJ, Gilmer TM, Martin AM, Marmorstein R, Schultz DC, Speicher DW, Karakousis GC, Xu W, Amaravadi RK, Xu X, Schuchter LM, Herlyn M, Nathanson KL. Concurrent MEK2 mutation and BRAF amplification confer resistance to BRAF and MEK inhibitors in melanoma. Cell Rep 2013; 4:1090-9. [PMID: 24055054 DOI: 10.1016/j.celrep.2013.08.023] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 07/10/2013] [Accepted: 08/14/2013] [Indexed: 10/26/2022] Open
Abstract
Although BRAF and MEK inhibitors have proven clinical benefits in melanoma, most patients develop resistance. We report a de novo MEK2-Q60P mutation and BRAF gain in a melanoma from a patient who progressed on the MEK inhibitor trametinib and did not respond to the BRAF inhibitor dabrafenib. We also identified the same MEK2-Q60P mutation along with BRAF amplification in a xenograft tumor derived from a second melanoma patient resistant to the combination of dabrafenib and trametinib. Melanoma cells chronically exposed to trametinib acquired concurrent MEK2-Q60P mutation and BRAF-V600E amplification, which conferred resistance to MEK and BRAF inhibitors. The resistant cells had sustained MAPK activation and persistent phosphorylation of S6K. A triple combination of dabrafenib, trametinib, and the PI3K/mTOR inhibitor GSK2126458 led to sustained tumor growth inhibition. Hence, concurrent genetic events that sustain MAPK signaling can underlie resistance to both BRAF and MEK inhibitors, requiring novel therapeutic strategies to overcome it.
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Affiliation(s)
- Jessie Villanueva
- Molecular and Cellular Oncogenesis Program, Melanoma Research Center, The Wistar Institute, Philadelphia, PA 19104, USA.
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Kim KB, Kefford R, Pavlick AC, Infante JR, Ribas A, Sosman JA, Fecher LA, Millward M, McArthur GA, Hwu P, Gonzalez R, Ott PA, Long GV, Gardner OS, Ouellet D, Xu Y, DeMarini DJ, Le NT, Patel K, Lewis KD. Phase II study of the MEK1/MEK2 inhibitor Trametinib in patients with metastatic BRAF-mutant cutaneous melanoma previously treated with or without a BRAF inhibitor. J Clin Oncol 2012; 31:482-9. [PMID: 23248257 DOI: 10.1200/jco.2012.43.5966] [Citation(s) in RCA: 355] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE BRAF mutations promote melanoma cell proliferation and survival primarily through activation of MEK. The purpose of this study was to determine the response rate (RR) for the selective, allosteric MEK1/MEK2 inhibitor trametinib (GSK1120212), in patients with metastatic BRAF-mutant melanoma. PATIENTS AND METHODS This was an open-label, two-stage, phase II study with two cohorts. Patients with metastatic BRAF-mutant melanoma previously treated with a BRAF inhibitor (cohort A) or treated with chemotherapy and/or immunotherapy (BRAF-inhibitor naive; cohort B) were enrolled. Patients received 2 mg of trametinib orally once daily. RESULTS In cohort A (n = 40), there were no confirmed objective responses and 11 patients (28%) with stable disease (SD); the median progression-free survival (PFS) was 1.8 months. In cohort B (n = 57), there was one (2%) complete response, 13 (23%) partial responses (PRs), and 29 patients (51%) with SD (confirmed RR, 25%); the median PFS was 4.0 months. One patient each with BRAF K601E and BRAF V600R had prolonged PR. The most frequent treatment-related adverse events for all patients were skin-related toxicity, nausea, peripheral edema, diarrhea, pruritis, and fatigue. No cutaneous squamous cell carcinoma was observed. CONCLUSION Trametinib was well tolerated. Significant clinical activity was observed in BRAF-inhibitor-naive patients previously treated with chemotherapy and/or immunotherapy. Minimal clinical activity was observed as sequential therapy in patients previously treated with a BRAF inhibitor. Together, these data suggest that BRAF-inhibitor resistance mechanisms likely confer resistance to MEK-inhibitor monotherapy. These data support further evaluation of trametinib in BRAF-inhibitor-naive BRAF-mutant melanoma, including rarer forms of BRAF-mutant melanoma.
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Affiliation(s)
- Kevin B Kim
- Department of Melanoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Falchook GS, Moy C, DeMarini DJ. Trametinib for patients with advanced melanoma – Authors' reply. Lancet Oncol 2012. [DOI: 10.1016/s1470-2045(12)70429-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Falchook GS, Lewis KD, Infante JR, Gordon MS, Vogelzang NJ, DeMarini DJ, Sun P, Moy C, Szabo SA, Roadcap LT, Peddareddigari VGR, Lebowitz PF, Le NT, Burris HA, Messersmith WA, O'Dwyer PJ, Kim KB, Flaherty K, Bendell JC, Gonzalez R, Kurzrock R, Fecher LA. Activity of the oral MEK inhibitor trametinib in patients with advanced melanoma: a phase 1 dose-escalation trial. Lancet Oncol 2012; 13:782-9. [PMID: 22805292 DOI: 10.1016/s1470-2045(12)70269-3] [Citation(s) in RCA: 404] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND MEK is a member of the MAPK signalling cascade that is commonly activated in melanoma. Direct inhibition of MEK blocks cell proliferation and induces apoptosis. We aimed to analyse safety, efficacy, and genotyping data for the oral, small-molecule MEK inhibitor trametinib in patients with melanoma. METHODS We undertook a multicentre, phase 1 three-part study (dose escalation, cohort expansion, and pharmacodynamic assessment). The main results of this study are reported elsewhere; here we present data relating to patients with melanoma. We obtained tumour samples to assess BRAF mutational status, and available tissues underwent exploratory genotyping analysis. Disease response was measured by Response Evaluation Criteria in Solid Tumors, and adverse events were defined by common toxicity criteria. This study is registered with ClinicalTrials.gov, number NCT00687622. FINDINGS 97 patients with melanoma were enrolled, including 81 with cutaneous or unknown primary melanoma (36 BRAF mutant, 39 BRAF wild-type, six BRAF status unknown), and 16 with uveal melanoma. The most common treatment-related adverse events were rash or dermatitis acneiform (n=80; 82%) and diarrhoea (44; 45%), most of which were grade 2 or lower. No cutaneous squamous-cell carcinomas were recorded. Of 36 patients with BRAF mutations, 30 had not received a BRAF inhibitor before; two complete responses (both confirmed) and ten partial responses (eight confirmed) were noted in this subgroup (confirmed response rate, 33%). Median progression-free survival of this subgroup was 5·7 months (95% CI 4·0-7·4). Of the six patients who had received previous BRAF inhibition, one unconfirmed partial response was recorded. Of 39 patients with BRAF wild-type melanoma, four partial responses were confirmed (confirmed response rate, 10%). INTERPRETATION Our data show substantial clinical activity of trametinib in melanoma and suggest that MEK is a valid therapeutic target. Differences in response rates according to mutations indicate the importance of mutational analyses in the future. FUNDING GlaxoSmithKline.
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Affiliation(s)
- Gerald S Falchook
- Department of Investigational Cancer Therapeutics, Division of Cancer Medicine, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Abstract
Hepatitis C virus (HCV) infection represents a significant health concern in over 170 million individuals worldwide. Recently, Huh7 cell-based hepatitis C virus replicon systems, which rely upon the expression and cooperation of viral nonstructural proteins to mediate replication of the entire hepatitis C virus genome, were shown to be useful for studying viral replication and antiviral agents. We report that expression of the viral RNA-dependent RNA polymerase (RdRp) in yeast cells, independent of other viral proteins, is necessary and sufficient for initiation of RNA synthesis in cis from 3'-nontranslated hepatitis C virus RNA. Furthermore, expression of the polymerase alone appears incapable of transcribing across the entire viral genome, most likely due to the secondary structure of the RNA. Other viral polypeptides, such as helicase, which are presumed to be present in the functional replicase complex, are predicted to facilitate RNA synthesis across highly structured regions.
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Affiliation(s)
- Douglas J DeMarini
- Department of Comparative Genomics, The Metabolic and Viral Diseases Center of Excellence for Drug Discovery, GlaxoSmithKline Pharmaceuticals, 1250 South Collegeville Road, UP1450, Collegeville, PA 19426, USA
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Kozubowski L, Panek H, Rosenthal A, Bloecher A, DeMarini DJ, Tatchell K. A Bni4-Glc7 phosphatase complex that recruits chitin synthase to the site of bud emergence. Mol Biol Cell 2003; 14:26-39. [PMID: 12529424 PMCID: PMC140225 DOI: 10.1091/mbc.e02-06-0373] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Bni4 is a scaffold protein in the yeast Saccharomyces cerevisiae that tethers chitin synthase III to the bud neck by interacting with septin neck filaments and with Chs4, a regulatory subunit of chitin synthase III. We show herein that Bni4 is also a limiting determinant for the targeting of the type 1 serine/threonine phosphatase (Glc7) to the bud neck. Yeast cells containing a Bni4 variant that fails to associate with Glc7 fail to tether Chs4 to the neck, due in part to the failure of Bni4(V831A/F833A) to localize properly. Conversely, the Glc7-129 mutant protein fails to bind Bni4 properly and glc7-129 mutants exhibit reduced levels of Bni4 at the bud neck. Bni4 is phosphorylated in a cell cycle-dependent manner and Bni4(V831A/F833A) is both hyperphosphorylated and mislocalized in vivo. Yeast cells lacking the protein kinase Hsl1 exhibit increased levels of Bni4-GFP at the bud neck. GFP-Chs4 does not accumulate at the incipient bud site in either a bni4::TRP1 or a bni4(V831A/F833A) mutant but does mobilize to the neck at cytokinesis. Together, these results indicate that the formation of the Bni4-Glc7 complex is required for localization to the site of bud emergence and for subsequent targeting of chitin synthase.
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Affiliation(s)
- Lukasz Kozubowski
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130, USA
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Tunbridge E, Dingwall C, Edge C, Konduri M, DeMarini DJ, Livi GP, Maycox PR. Mutation of charged residues in the TR3 death domain does not perturb interaction with TRADD. Protein Eng Des Sel 2002; 15:811-5. [PMID: 12468715 DOI: 10.1093/protein/15.10.811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Members of the death receptor family play a prominent role in developmental and pathological neuronal cell death. The death signal is transduced via interaction between the death domain of the receptor and an intracellular adapter, TRADD. We performed alanine-scanning mutagenesis of specific charged residues in the TR3 death domain to determine whether they play a crucial role in TR3-TR3 and TR3-TRADD interaction. Mutation of charged residues in the second and third helices of the TR3 death domain failed to perturb self-interaction or interaction with TRADD. These data suggest that despite some similarity between the death domains of TR3 and TNFR1 the nature of the interaction with TRADD differs from that reported for TNFR1.
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Affiliation(s)
- Elisabeth Tunbridge
- Psychiatry Centre of Excellence for Drug Discovery, GlaxoSmithKline, Third Avenue, Harlow, EssexCM19 5AW, UK
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Khandekar SS, Silverman C, Wells-Marani J, Bacon AM, Birrell H, Brigham-Burke M, DeMarini DJ, Jonak ZL, Camilleri P, Fishman-Lobell J. Determination of carbohydrate structures N-linked to soluble CD154 and characterization of the interactions of CD40 with CD154 expressed in Pichia pastoris and Chinese hamster ovary cells. Protein Expr Purif 2001; 23:301-10. [PMID: 11676606 DOI: 10.1006/prep.2001.1501] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CD40-CD154 (CD40 ligand) interactions are essential for the development of protective immunity. Previous studies have described the CD40 binding site as a shallow groove formed between two monomers of CD154. However, these studies have not examined the structure or biological function of the carbohydrate on CD154. Human CD154 contains a single N-linked glycosylation site at asparagine 240. We have characterized the interactions between CD40 and soluble (s) CD154 in which sCD154 contains different types of carbohydrates. Detailed carbohydrate analysis revealed high-mannose structures on sCD154 purified from Pichia pastoris, whereas CD154 purified from Chinese hamster ovary E1A contained heterogeneous populations of complex carbohydrates. sCD154 purified from either system was trimeric, it bound to CD40 with similar affinities of 10-30 nM, and it functionally induced CD69 and CD95 expression on primary B cells. Together, these results indicate that the presence of varied types of N-linked glycans on asparagine 240 of CD154 does not play a significant role in the CD40-CD154 interactions.
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Affiliation(s)
- S S Khandekar
- Department of Protein Biochemistry, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406, USA
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Abstract
Initial steps in investigating gene function often include deleting and overexpressing the gene of interest and identifying the subcellular location of the gene product. To facilitate these procedures, a number of new PCR modules, which contain selectable markers and in some cases other genetic elements (e.g promoter elements, epitope tags, and reporter genes) have been developed. These modules are used as PCR substrates to create products that can be targeted to specified locations in the yeast genome, thus modifying that genomic locus. We describe here a series of plasmids that contain a truncated version of the strong ADH1 promoter with and without amino-terminal 3HA and GST tags. Because these plasmids contain the same vector sequences as the GAL1 promoter plasmids, a constitutive and an inducible promoter can now be integrated with a minimal number of primers.
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Affiliation(s)
- D J DeMarini
- Department of Comparative Genetics, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406, USA.
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DeMarini DJ, Creasy CL, Lu Q, Mao J, Sheardown SA, Sathe GM, Livi GP. Oligonucleotide-mediated, PCR-independent cloning by homologous recombination. Biotechniques 2001; 30:520-3. [PMID: 11252788 DOI: 10.2144/01303st02] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We have developed an oligonucleotide-mediated cloning technique based on homologous recombination in Saccharomyces cerevisiae that allows precise DNA sequences to be transferred independent of restriction enzymes and PCR. In this procedure, linear DNA sequences are targeted to a chosen site in a yeast vector by DNA linkers, which consist of two partially overlapping oligonucleotides. The linkers contain relatively short regions of both yeast vector sequences and insert sequences, which stimulate homologous recombination between the vector and the insert. The linkers can also contain sequences not found in either the vector or the insert (e.g., sequences that encode ribosome binding sites, epitope tags, preferred codons, etc.), thus allowing modification of the transferred DNA. Linkers can be designed such that DNA sequences can be transferred with just two reusable universal oligonucleotides and two gene-specific oligonucleotides. This cloning method, which is performed by co-transforming yeast with linear vector, substrate DNA, and unannealed oligonucleotides, has been termed the yeast-based, oligonucleotide-mediated gap repair technique (YOGRT).
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Affiliation(s)
- D J DeMarini
- Department of Comparative Genetics, Mail Code UE0548, SmithKline Beecham Pharmaceuticals, P.O. Box 1539, King of Prussia, PA 19506, USA.
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DeMarini DJ, Adams AE, Fares H, De Virgilio C, Valle G, Chuang JS, Pringle JR. A septin-based hierarchy of proteins required for localized deposition of chitin in the Saccharomyces cerevisiae cell wall. J Cell Biol 1997; 139:75-93. [PMID: 9314530 PMCID: PMC2139831 DOI: 10.1083/jcb.139.1.75] [Citation(s) in RCA: 267] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/1997] [Revised: 06/17/1997] [Indexed: 02/05/2023] Open
Abstract
Just before bud emergence, a Saccharomyces cerevisiae cell forms a ring of chitin in its cell wall; this ring remains at the base of the bud as the bud grows and ultimately forms part of the bud scar marking the division site on the mother cell. The chitin ring seems to be formed largely or entirely by chitin synthase III, one of the three known chitin synthases in S. cerevisiae. The chitin ring does not form normally in temperature-sensitive mutants defective in any of four septins, a family of proteins that are constituents of the "neck filaments" that lie immediately subjacent to the plasma membrane in the mother-bud neck. In addition, a synthetic-lethal interaction was found between cdc12-5, a temperature-sensitive septin mutation, and a mutant allele of CHS4, which encodes an activator of chitin synthase III. Two-hybrid analysis revealed no direct interaction between the septins and Chs4p but identified a novel gene, BNI4, whose product interacts both with Chs4p and Cdc10p and with one of the septins, Cdc10p; this analysis also revealed an interaction between Chs4p and Chs3p, the catalytic subunit of chitin synthase III. Bni4p has no known homologues; it contains a predicted coiled-coil domain, but no other recognizable motifs. Deletion of BNI4 is not lethal, but causes delocalization of chitin deposition and aberrant cellular morphology. Overexpression of Bni4p also causes delocalization of chitin deposition and produces a cellular morphology similar to that of septin mutants. Immunolocalization experiments show that Bni4p localizes to a ring at the mother-bud neck that lies predominantly on the mother-cell side (corresponding to the predominant site of chitin deposition). This localization depends on the septins but not on Chs4p or Chs3p. A GFP-Chs4p fusion protein also localizes to a ring at the mother-bud neck on the mother-cell side. This localization is dependent on the septins, Bni4p, and Chs3p. Chs3p, whose normal localization is similar to that of Chs4p, does not localize properly in bni4, chs4, or septin mutant strains or in strains that accumulate excess Bni4p. In contrast, localization of the septins is essentially normal in bni4, chs4, and chs3 mutant strains and in strains that accumulate excess Bni4p. Taken together, these results suggest that the normal localization of chitin synthase III activity is achieved by assembly of a complex in which Chs3p is linked to the septins via Chs4p and Bni4p.
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Affiliation(s)
- D J DeMarini
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280, USA
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De Virgilio C, DeMarini DJ, Pringle JR. SPR28, a sixth member of the septin gene family in Saccharomyces cerevisiae that is expressed specifically in sporulating cells. Microbiology (Reading) 1996; 142 ( Pt 10):2897-905. [PMID: 8885406 DOI: 10.1099/13500872-142-10-2897] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The septins are a recently recognized family of proteins that are present in a wide variety of fungal and animal cells, where they are involved in cytokinesis and apparently in other processes involving the organization of the cell surface. Five previously described Saccharomyces cerevisiae septins are associated with the neck filaments of vegetative cells and/or with the developing prospore wall of sporulating cells. We report here the characterization of SPR28, a sixth member of the S. cerevisiae septin gene family whose existence was revealed by the yeast genome project. Analysis of mRNA levels showed that SPR28 is a new member of the group of "late genes' that are expressed at high levels during the meiotic divisions and ascospore formation. The septin it encodes, Spr28p, exhibited specific two-hybrid interactions with itself and with three other septins that are expressed in sporulating cells. Consistent with these results, an Spr28p-green fluorescent protein fusion was induced during meiosis I and appeared to be associated with the developing prospore walls. Deletion of SPR28 in either a wild-type or an spr3 delta background produced no obvious abnormalities in vegetative cells and had little or no effect on sporulation, suggesting that the septins have redundant roles during spore formation.
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Affiliation(s)
- C De Virgilio
- Department of Biology, University of North Carolina, Chapel Hill 27599, USA
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Abstract
The septins are a novel family of proteins that were first recognized in yeast as proteins associated with the neck filaments. Recent work has shown that septins are also present in other fungi, insects, and vertebrates. Despite the apparent differences in modes of cytokinesis amongst species, septins appear to be essential for this process in both fungal and animal cells. The septins also appear to be involved in various other aspects of the organization of the cell surface.
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Affiliation(s)
- M S Longtine
- Department of Biology, University of North Carolina, Chapel Hill 27599-3280, USA
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Abstract
A mutation in the Saccharomyces cerevisiae SEN1 gene causes accumulation of end-matured, intron-containing pre-tRNAs. Cells containing the thermosensitive sen1-1 mutation exhibit reduced tRNA splicing endonuclease activity. However, Sen1p is not the catalytic subunit of this enzyme. We have used Sen1p-specific antibodies for cell fractionation studies and immunofluorescent microscopy and determined that Sen1p is a low abundance protein of about 239 kDa. It localizes to the nucleus with a granular distribution. We verified that a region in SEN1 containing a putative nuclear localization signal sequence (NLS) is necessary for nuclear targeting. Furthermore, we found that inactivation of Sen1p by temperature shift of a strain carrying sen1-1 leads to mislocalization of two nucleolar proteins, Nop1 and Ssb1. Possible mechanisms are discussed for several related nuclear functions of Sen1p, including tRNA splicing and the maintenance of a normal crescent-shaped nucleolus.
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Affiliation(s)
- D Ursic
- Laboratory of Genetics, University of Wisconsin, Madison 53706, USA
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DeMarini DJ, Papa FR, Swaminathan S, Ursic D, Rasmussen TP, Culbertson MR, Hochstrasser M. The yeast SEN3 gene encodes a regulatory subunit of the 26S proteasome complex required for ubiquitin-dependent protein degradation in vivo. Mol Cell Biol 1995; 15:6311-21. [PMID: 7565784 PMCID: PMC230883 DOI: 10.1128/mcb.15.11.6311] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The yeast Sen1 protein was discovered by virtue of its role in tRNA splicing in vitro. To help determine the role of Sen1 in vivo, we attempted to overexpress the protein in yeast cells. However, cells with a high-copy SEN1-bearing plasmid, although expressing elevated amounts of SEN1 mRNA, show little increase in the level of the encoded protein, indicating that a posttranscriptional mechanism limits SEN1 expression. This control depends on an amino-terminal element of Sen1. Using a genetic selection for mutants with increased expression of Sen1-derived fusion proteins, we identified mutations in a novel gene, designated SEN3. SEN3 is essential and encodes a 945-residue protein with sequence similarity to a subunit of an activator of the 20S proteasome from bovine erythrocytes, called PA700. Earlier work indicated that the 20S proteasome associates with a multisubunit regulatory factor, resulting in a 26S proteasome complex that degrades substrates of the ubiquitin system. Mutant sen3-1 cells have severe defects in the degradation of such substrates and accumulate ubiquitin-protein conjugates. Most importantly, we show biochemically that Sen3 is a subunit of the 26S proteasome. These data provide evidence for the involvement of the 26S proteasome in the degradation of ubiquitinated proteins in vivo and for a close relationship between PA700 and the regulatory complexes within the 26S proteasome, and they directly demonstrate that Sen3 is a component of the yeast 26S proteasome.
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Affiliation(s)
- D J DeMarini
- Laboratory of Genetics and Molecular Biology, University of Wisconsin, Madison 53706, USA
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Abstract
The SEN1 gene, which is essential for growth in the yeast Saccharomyces cerevisiae, is required for endonucleolytic cleavage of introns from all 10 families of precursor tRNAs. A mutation in SEN1 conferring temperature-sensitive lethality also causes in vivo accumulation of pre-tRNAs and a deficiency of in vitro endonuclease activity. Biochemical evidence suggests that the gene product may be one of several components of a nuclear-localized splicing complex. We have cloned the SEN1 gene and characterized the SEN1 mRNA, the SEN1 gene product, the temperature-sensitive sen1-1 mutation, and three SEN1 null alleles. The SEN1 gene corresponds to a 6,336-bp open reading frame coding for a 2,112-amino-acid protein (molecular mass, 239 kDa). Using antisera directed against the C-terminal end of SEN1, we detect a protein corresponding to the predicted molecular weight of SEN1. The SEN1 protein contains a leucine zipper motif, consensus elements for nucleoside triphosphate binding, and a potential nuclear localization signal sequence. The carboxy-terminal 1,214 amino acids of the SEN1 protein are essential for growth, whereas the amino-terminal 898 amino acids are dispensable. A sequence of approximately 500 amino acids located in the essential region of SEN1 has significant similarity to the yeast UPF1 gene product, which is involved in mRNA turnover, and the mouse Mov-10 gene product, whose function is unknown. The mutation that creates the temperature-sensitive sen1-1 allele is located within this 500-amino-acid region, and it causes a substitution for an amino acid that is conserved in all three proteins.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Base Sequence
- Binding Sites
- Blotting, Northern
- Cloning, Molecular
- DNA Helicases
- DNA Probes
- DNA, Fungal/genetics
- DNA, Fungal/isolation & purification
- Endoribonucleases/metabolism
- Fungal Proteins/genetics
- Fungal Proteins/metabolism
- Genes, Fungal
- Genotype
- Models, Genetic
- Molecular Sequence Data
- Mutation
- Open Reading Frames
- RNA Helicases
- RNA Splicing
- RNA, Fungal/genetics
- RNA, Fungal/isolation & purification
- RNA, Messenger/genetics
- RNA, Messenger/isolation & purification
- RNA, Transfer/genetics
- Restriction Mapping
- Saccharomyces cerevisiae/enzymology
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae Proteins
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Affiliation(s)
- D J DeMarini
- Laboratory of Genetics, University of Wisconsin, Madison 53706
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24
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Tiedeman AA, DeMarini DJ, Parker J, Smith JM. DNA sequence of the purC gene encoding 5'-phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide synthetase and organization of the dapA-purC region of Escherichia coli K-12. J Bacteriol 1990; 172:6035-41. [PMID: 2120198 PMCID: PMC526926 DOI: 10.1128/jb.172.10.6035-6041.1990] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
5'-Phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide synthetase (EC 6.3.2.6), encoded by the purC gene of Escherichia coli K-12, catalyzes the synthesis of 5'-phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide from 5'-phosphoribosyl-5-aminoimidazole-4-carboxylic acid. The mature protein, as deduced from the purC structural gene sequence, contains 237 amino acids and has a calculated Mr of 26,998. The control region of the purC gene was identified by primer extension mapping of the 5' end of the purC mRNA. The purC control region contains a binding site for and is regulated by the purine repressor, the product of the purR gene. An unusual feature of the 5' untranslated region of the purC mRNA is the presence of a repetitive extragenic palindrome sequence normally found in intercistronic or 3' untranslated regions. The DNA sequence was extended 1.281 kilobases upstream of the purC structural gene and overlapped with the previously determined dapA sequence. Termination of transcription from the dapA-purC intercistronic region may occur within the -35 region of the purC control region. The purC gene has been positioned on the E. coli restriction map and is transcribed in a counterclockwise direction.
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Affiliation(s)
- A A Tiedeman
- Seattle Biomedical Research Institute, Washington 98109
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25
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Vesonder RF, Ellis JJ, Kwolek WF, DeMarini DJ. Production of vomitoxin on corn by Fusarium graminearum NRRL 5883 and Fusarium roseum NRRL 6101. Appl Environ Microbiol 1982; 43:967-70. [PMID: 7081990 PMCID: PMC241951 DOI: 10.1128/aem.43.4.967-970.1982] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Two vomitoxin-producing isolates of Fusarium spp. were grown on cracked corn for 1 to 8 weeks at 15, 20, 25, 28, and 32 degrees C. Maximum production of vomitoxin by Fusarium graminearum Schw. NRRL 5883 occurred at 30 degrees C and 40 days, and that by Fusarium roseum Schw. NRRL 6101 occurred at 26 degrees C and 41 days. These optimum production points were determined from response surface contour graphs in relation to temperature and time. Only small amounts of vomitoxin were produced at 15 and 20 degrees C by each strain. A 133-microgram quantity of vomitoxin, with an indicated purity of 95%, was isolated per gram of corn fermented with F. graminearum NRRL 5883.
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