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O'Neil M, Laba JM, Nguyen TK, Lock M, Goodman CD, Huynh E, Snir J, Munro V, Alce J, Schrijver L, Lemay S, MacDonald T, Warner A, Palma DA. Diagnostic CT-Enabled Planning (DART): Results of a Randomized Trial in Palliative Radiation Therapy. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00396-1. [PMID: 38613562 DOI: 10.1016/j.ijrobp.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/12/2024] [Accepted: 03/04/2024] [Indexed: 04/15/2024]
Abstract
PURPOSE Using diagnostic computed tomography (dCT) scans instead of CT simulation (CTsim) scans can increase departmental efficiency and reduce patient burden. The goal of the DART trial was to assess the efficacy and acceptability of dCT-based planning workflows with a focus on patient experiences, plan deliverability and adequacy of target coverage, and workflows. METHODS AND MATERIALS Patients undergoing same-day CTsim and treatment for palliative radiation therapy to thoracic, abdominopelvic, or proximal limb targets with a recent dCT (within 28 days) in a reproducible position were eligible. After stratifying by target type (bone or soft tissue vs. visceral), participants were randomized (1:2 ratio) between CTsim-based (CTsim arm) vs. dCT-based planning (dCT arm). The primary endpoint was time in center (TIC), defined as total time spent in the cancer center on first day of treatment, from first radiation department appointment to first fraction completion. Secondary endpoints included plan deliverability, adequacy of target coverage, and stakeholder acceptability. RESULTS Thirty-three patients (42 treatment sites) were enrolled between June 2022 and April 2023. The median age was 72 (interquartile range [IQR]: 67-78), 73% were male, and the most common primary cancers were lung (33%), prostate (24%), and breast (12%). The most common dose and fractionations were 8 Gy in 1 and 20 Gy in 5 fractions (50% and 43% of plans, respectively). TIC was 4.7 ± 1.1 hours (mean ± SD) in the CTsim arm vs. 0.41 ± 0.14 hours in the dCT arm (P < .001). All dCT plans were deliverable. All plans in both arms were rated as "acceptable" (80% CTsim; 81% dCT) or "acceptable with minor deviation" (20% CTsim; 19% dCT). Patient perception of acceptability was similar in both arms with the exception of time burden, which was rated as "acceptable" by 50% in the CTsim arm vs. 90% in the dCT arm (P = .025). CONCLUSION dCT-based radiation planning substantially reduced TIC without detriment in plan deliverability or quality and had a tangible impact on patient experience with reduced patient-reported time burden.
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Affiliation(s)
- Melissa O'Neil
- Department of Radiation Therapy, London Health Sciences Centre, London, Ontario, Canada
| | - Joanna M Laba
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
| | - Timothy K Nguyen
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
| | - Michael Lock
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
| | - Christopher D Goodman
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
| | - Elizabeth Huynh
- Department of Medical Biophysics, London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
| | - Jonatan Snir
- Department of Medical Biophysics, London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada
| | - Vikki Munro
- Department of Radiation Therapy, London Health Sciences Centre, London, Ontario, Canada
| | - Jenna Alce
- Department of Radiation Therapy, London Health Sciences Centre, London, Ontario, Canada
| | - Lidia Schrijver
- Department of Radiation Therapy, London Health Sciences Centre, London, Ontario, Canada
| | - Sylvia Lemay
- Department of Radiation Therapy, London Health Sciences Centre, London, Ontario, Canada
| | - Tara MacDonald
- Department of Radiation Therapy, London Health Sciences Centre, London, Ontario, Canada
| | - Andrew Warner
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - David A Palma
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada; Department of Oncology, Western University, London, Ontario, Canada.
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Palma DA, Bahig H, Hope A, Harrow S, Debenham BJ, Louie AV, Vu TTT(T, Filion E, Bezjak A, Campeau MP, Duimering A, Giuliani ME, Laba JM, Lang P, Lok BH, Qu XM, Raman S, Rodrigues GB, Goodman CD, Gaede S, Morisset J, Warner A, Dhaliwal I, Ryerson CJ. Stereotactic Radiation Therapy in Early Non-Small Cell Lung Cancer and Interstitial Lung Disease: A Nonrandomized Clinical Trial. JAMA Oncol 2024:2815670. [PMID: 38451491 PMCID: PMC10921346 DOI: 10.1001/jamaoncol.2023.7269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/25/2023] [Indexed: 03/08/2024]
Abstract
Importance Patients with interstitial lung disease (ILD) and early-stage non-small cell lung cancer (NSCLC) have been reported to be at high risk of toxic effects after stereotactic ablative radiotherapy (SABR), but for many patients, there are limited alternative treatment options. Objective To prospectively assess the benefits and toxic effects of SABR in this patient population. Design, Setting, and Participants This prospective cohort study was conducted at 6 academic radiation oncology institutions, 5 in Canada and 1 in Scotland, with accrual between March 7, 2019, and January 12, 2022. Patients aged 18 years or older with fibrotic ILD and a diagnosis of T1-2N0 NSCLC who were not candidates for surgical resection were enrolled. Intervention Patients were treated with SABR to a dose of 50 Gy in 5 fractions every other day. Main Outcomes and Measures The study prespecified that SABR would be considered worthwhile if median overall survival-the primary end point-was longer than 1 year, with a grade 3 to 4 risk of toxic effects less than 35% and a grade 5 risk of toxic effects less than 15%. Secondary end points included toxic effects, progression-free survival (PFS), local control (LC), quality-of-life outcomes, and changes in pulmonary function. Intention-to-treat analysis was conducted. Results Thirty-nine patients enrolled and received SABR. Median age was 78 (IQR, 67-83) years and 59% (n = 23) were male. At baseline, 70% (26 of 37) of patients reported dyspnea, median forced expiratory volume in first second of expiration was 80% (IQR, 66%-90%) predicted, median forced vital capacity was 84% (IQR, 69%-94%) predicted, and median diffusion capacity of the lung for carbon monoxide was 49% (IQR, 38%-61%) predicted. Median follow-up was 19 (IQR, 14-25) months. Overall survival at 1 year was 79% (95%, CI 62%-89%; P < .001 vs the unacceptable rate), and median overall survival was 25 months (95% CI, 14 months to not reached). Median PFS was 19 months (95% CI, 13-28 months), and 2-year LC was 92% (95% CI, 69%-98%). Adverse event rates (highest grade per patient) were grade 1 to 2: n = 12 (31%), grade 3: n = 4 (10%), grade 4: n = 0, and grade 5: n = 3 (7.7%, all due to respiratory deterioration). Conclusions and Relevance In this trial, use of SABR in patients with fibrotic ILD met the prespecified acceptability thresholds for both toxicity and efficacy, supporting the use of SABR for curative-intent treatment after a careful discussion of risks and benefits. Trial Registration ClinicalTrials.gov Identifier: NCT03485378.
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Affiliation(s)
- David A. Palma
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Houda Bahig
- Department of Radiation Oncology, Centre Hospitalier de l’Université de Montréal, Montréal, Quebec, Canada
| | - Andrew Hope
- Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | | | - Brock J. Debenham
- Department of Radiation Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Alexander V. Louie
- Department of Radiation Oncology, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Thi Trinh Thuc (Toni) Vu
- Department of Radiation Oncology, Centre Hospitalier de l’Université de Montréal, Montréal, Quebec, Canada
| | - Edith Filion
- Department of Radiation Oncology, Centre Hospitalier de l’Université de Montréal, Montréal, Quebec, Canada
| | - Andrea Bezjak
- Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Marie-Pierre Campeau
- Department of Radiation Oncology, Centre Hospitalier de l’Université de Montréal, Montréal, Quebec, Canada
| | - Adele Duimering
- Department of Radiation Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Meredith E. Giuliani
- Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Joanna M. Laba
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Pencilla Lang
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Benjamin H. Lok
- Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - X. Melody Qu
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Srinivas Raman
- Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - George B. Rodrigues
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Christopher D. Goodman
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Stewart Gaede
- Department of Medical Physics, Western University, London, Ontario, Canada
| | - Julie Morisset
- Department of Medicine, Centre Hospitalier de l’Université de Montréal, Montréal, Quebec, Canada
| | - Andrew Warner
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Inderdeep Dhaliwal
- Department of Respirology, London Health Sciences Centre, London, Ontario, Canada
| | - Christopher J. Ryerson
- Department of Medicine and Centre for Heart Lung Innovation, University of British Columbia, Vancouver, British Columbia, Canada
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Goodman CD, Garden AS, Wang H, Wang XA, Diao K, Lee A, Reddy J, Moreno AC, Spiotto MT, Fuller CD, Rosenthal DI, Ferrarotto R, Raza SM, Su SY, Hanna EY, DeMonte F, Phan J. Fractionated Stereotactic Radiotherapy in the Management of Dural Recurrence of Olfactory Neuroblastoma. Int J Radiat Oncol Biol Phys 2023; 117:e585-e586. [PMID: 37785774 DOI: 10.1016/j.ijrobp.2023.06.1929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Treatment protocols for dural recurrence among esthesioneuroblastoma patients have not been standardized. We assess the outcomes of fractionated stereotactic radiotherapy (FSR) for patients with olfactory neuroblastoma (ONB) dura-based recurrences. MATERIALS/METHODS We identified ONB patients with dura-based recurrences treated with FSR after prior radiotherapy who were enrolled between 2013 and 2022 in our prospective head and neck reirradiation and skull base registries. In-field tumor control (within 2 cm of prescribed radiotherapy volume) and out-of-field tumor control (non-contiguous or contralateral dura, nodal, or distant metastases) were analyzed. RESULTS Thirteen patients with 28 dural lesions were included in this analysis. All patients were initially treated with surgery to their primary paranasal sinus disease; 69% with a craniofacial approach followed by adjuvant radiotherapy to a median dose of 63 Gy (range 60-72.4 Gy) prescribed to the resected tumor bed. Patients re-presented with dural recurrence at median 58.3 months (range 35.0 - 163.0 months) from completion of their initial treatment. Two patients underwent dural resections. On presentation of recurrence, 4 patients had 1 lesion treated, with a median of 2 lesions treated (range 1-4 lesions). All dural based tumors were treated with FSR to a median dose of 27 Gy in 3 fractions delivered QOD. 68Ga-DOTATATE PET/CT was utilized for FSR treatment planning in 31% of cases. The median follow up from FSR was 23.3 months (range: 13.1 - 51.6 months). The 1-year overall survival and progression free survival was 75% and 38%, respectively. The 1- and 2-year in-field control rate was 85% and 75%, respectively. Among treated lesions, 25 of 28 (89%) responded or remained stable following FSR. Two patients (3 lesions) had evidence of in-field radiographic progression at 17 and 9 months, respectively. Five patients (38%) experienced progression in the contralateral or non-contiguous dura, and 5 patients (38%) developed distant metastases. The overall out-of-field progression rate was 58% at 1 year. There was no grade 3 or higher toxicity observed. Three patients (23%) developed asymptomatic changes on MRI consistent with brain necrosis, all of which occurred in a previously irradiated region. CONCLUSION In the largest single institution study of FSR reirradiation for ONB dural recurrence to date, high local control rates with minimal toxicity are attainable. However, subsequent out-of-field dural recurrences and/or distant metastases remain problematic.
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Affiliation(s)
- C D Goodman
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - A S Garden
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - H Wang
- Department of Radiation Physics, The University of Texas, MD Anderson Cancer Center, Houston, TX
| | - X A Wang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - K Diao
- University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - A Lee
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - J Reddy
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - A C Moreno
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - M T Spiotto
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - C D Fuller
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - D I Rosenthal
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - R Ferrarotto
- Department of Thoracic Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - S M Raza
- Department of Neurosurgery, University of Texas MD Anderson Cancer Center, Houston, TX
| | - S Y Su
- Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - E Y Hanna
- Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - F DeMonte
- The University of Texas MD Anderson Cancer Center, Houston, TX
| | - J Phan
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
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Burns AL, Sleebs BE, Gancheva M, McLean KT, Siddiqui G, Venter H, Beeson JG, O’Handley R, Creek DJ, Ma S, Frölich S, Goodman CD, McFadden GI, Wilson DW. Targeting malaria parasites with novel derivatives of azithromycin. Front Cell Infect Microbiol 2022; 12:1063407. [PMID: 36530422 PMCID: PMC9748569 DOI: 10.3389/fcimb.2022.1063407] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/09/2022] [Indexed: 12/02/2022] Open
Abstract
Introduction The spread of artemisinin resistant Plasmodium falciparum parasites is of global concern and highlights the need to identify new antimalarials for future treatments. Azithromycin, a macrolide antibiotic used clinically against malaria, kills parasites via two mechanisms: 'delayed death' by inhibiting the bacterium-like ribosomes of the apicoplast, and 'quick-killing' that kills rapidly across the entire blood stage development. Methods Here, 22 azithromycin analogues were explored for delayed death and quick-killing activities against P. falciparum (the most virulent human malaria) and P. knowlesi (a monkey parasite that frequently infects humans). Results Seventeen analogues showed improved quick-killing against both Plasmodium species, with up to 38 to 20-fold higher potency over azithromycin after less than 48 or 28 hours of treatment for P. falciparum and P. knowlesi, respectively. Quick-killing analogues maintained activity throughout the blood stage lifecycle, including ring stages of P. falciparum parasites (<12 hrs treatment) and were >5-fold more selective against P. falciparum than human cells. Isopentenyl pyrophosphate supplemented parasites that lacked an apicoplast were equally sensitive to quick-killing analogues, confirming that the quick killing activity of these drugs was not directed at the apicoplast. Further, activity against the related apicoplast containing parasite Toxoplasma gondii and the gram-positive bacterium Streptococcus pneumoniae did not show improvement over azithromycin, highlighting the specific improvement in antimalarial quick-killing activity. Metabolomic profiling of parasites subjected to the most potent compound showed a build-up of non-haemoglobin derived peptides that was similar to chloroquine, while also exhibiting accumulation of haemoglobin-derived peptides that was absent for chloroquine treatment. Discussion The azithromycin analogues characterised in this study expand the structural diversity over previously reported quick-killing compounds and provide new starting points to develop azithromycin analogues with quick-killing antimalarial activity.
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Affiliation(s)
- Amy L. Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia,School of Science and Technology, the University of New England, Armidale, NSW, Australia
| | - Brad E. Sleebs
- ACRF Chemical Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Maria Gancheva
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | - Kimberley T. McLean
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | - Ghizal Siddiqui
- Drug Delivery Disposition and Dynamics, Monash University, Parkville, VIC, Australia
| | - Henrietta Venter
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - James G. Beeson
- Healthy Mothers, Healthy Babies Program, Burnet Institute, Melbourne, VIC, Australia,Department of Medicine, University of Melbourne, Parkville, VIC, Australia,Central Clinical School, Monash University, Melbourne, Vic, Australia,Department of Microbiology, Monash University, Melbourne, Vic, Australia
| | - Ryan O’Handley
- School of Animal and Veterinary Science, University of Adelaide, Adelaide, SA, Australia,Australian Centre for Antimicrobial Resistance Ecology, The University of Adelaide, Adelaide, SA, Australia
| | - Darren J. Creek
- Drug Delivery Disposition and Dynamics, Monash University, Parkville, VIC, Australia
| | - Shutao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Sonja Frölich
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | | | | | - Danny W. Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia,Healthy Mothers, Healthy Babies Program, Burnet Institute, Melbourne, VIC, Australia,Australian Centre for Antimicrobial Resistance Ecology, The University of Adelaide, Adelaide, SA, Australia,*Correspondence: Danny W. Wilson,
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Zayed S, Goodman CD, Mutsaers A, Palma DA, Velker V, Laba JM, Nguyen TK. Evaluating The Oncology Research Internship (Orion) During the Covid-19 Pandemic: A Comparison of Virtual and In-Person Iterations. Int J Radiat Oncol Biol Phys 2022. [PMCID: PMC9366022 DOI: 10.1016/j.ijrobp.2022.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background The Oncology Research Internship (ORIoN), a novel resident-supervised initiative for medical students (MS), was first established in 2018 and found to be beneficial to both residents and MS. The COVID-19 pandemic halted many scholarly programs which relied heavily on mentorship through in-person interactions. We report results of the first virtual program, adapted to the COVID-19 pandemic, and compare participant feedback to previous in-person iterations. Methods ORIoN applications were open to first- and second-year MS. A panel of 3 physicians reviewed and scored applications. Successful MS applicants were paired with resident supervisors; each pair supervised by a staff oncologist. Compared to previous years, all meetings, correspondences and presentations between MS, residents, and supervising oncologists were conducted exclusively remotely. At the program's conclusion, each MS delivered a live virtual oral presentation of their completed case report, previously done in-person. Resident and MS participants completed questionnaires pre-/post program. Responses were collected on a 5-point Likert scale. Survey results from this virtual and the previous in-person programs were compared. Results Of 54 applications (previously 32 in 2018), 9 MS (three first-year, six second-year) were accepted and assigned to 9 volunteer residents (6 radiation oncology, 2 medical oncology, 1 pathology). To date, 9 manuscripts have been completed with 2 submitted for publication (1 published, 1 under review). Survey response rates were 100% (9/9) for residents and 89% (8/9) for MS. In the post-program surveys comparing the virtual and prior in-person programs, 87.5% (7/8) MS felt comfortable completing a clinical research project (22% strongly agree (SA), 62.5% agree (A), previously 25% and 75% respectively) and 100% (8/8) felt comfortable writing a case report (50% SA, 50% A, previously 75%, 25% respectively). All MS felt comfortable giving an oral research presentation (37.5% SA, 62.5% A) and teaching another MS to complete a case report (37.5% SA, 50% A). Similar to the in-person program, MS unanimously agreed that ORIoN was a beneficial experience (100%) and felt the program contributed to their career goals (100%, previously 88%). Post-program, all residents felt comfortable as a supervisor (67% SA, 22% A, previously 33%, 67% respectively), reviewing manuscripts (56% SA, 33% A, previously 33%, 50% respectively) and providing constructive feedback to trainees (67% SA, 33% A, previously 17%, 67% respectively). Discussion Compared to the in-person program, the virtual ORIoN retained strongly favourable ratings from MS and residents alike. These findings support adapting similar programs to a virtual setting when in-person interactions are not feasible.
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Buchanan HD, Goodman CD, McFadden GI. Roles of the apicoplast across the life cycles of rodent and human malaria parasites. J Eukaryot Microbiol 2022; 69:e12947. [PMID: 36070203 PMCID: PMC9828729 DOI: 10.1111/jeu.12947] [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] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Malaria parasites are diheteroxenous, requiring two hosts-a vertebrate and a mosquito-to complete their life cycle. Mosquitoes are the definitive host where malaria parasite sex occurs, and vertebrates are the intermediate host, supporting asexual amplification and more significant geographic spread. In this review, we examine the roles of a single malaria parasite compartment, the relict plastid known as the apicoplast, at each life cycle stage. We focus mainly on two malaria parasite species-Plasmodium falciparum and P. berghei-comparing the changing, yet ever crucial, roles of their apicoplasts.
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Affiliation(s)
- Hayley D. Buchanan
- Department of Infectious Diseases, Faculty of Medicine, Dentistry and Health Sciences, Melbourne Medical SchoolThe University of MelbourneMelbourneVic.Australia,Faculty of Science, School of BioSciencesThe University of MelbourneMelbourneVic.Australia
| | - Christopher D. Goodman
- Faculty of Science, School of BioSciencesThe University of MelbourneMelbourneVic.Australia
| | - Geoffrey I. McFadden
- Faculty of Science, School of BioSciencesThe University of MelbourneMelbourneVic.Australia
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Holzinger A, Obwegeser S, Andosch A, Karsten U, Oppermann C, Ruth W, van de Meene A, Goodman CD, Lütz-Meindl U, West JA. The red alga Tsunamia transpacifica (Stylonematophyceae) from plastic drift shows adaptation to its uncommon habitat in ultrastructure and soluble low molecular weight carbohydrate composition. Protoplasma 2021; 258:1307-1321. [PMID: 34170416 PMCID: PMC8523428 DOI: 10.1007/s00709-021-01674-6] [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] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 05/30/2021] [Indexed: 06/13/2023]
Abstract
The recently described red alga Tsunamia transpacifica (Stylonematophyceae) was previously isolated from plastic drift found at the pacific coast, but the natural habitat remains unknown. Here, we investigate ultrastructural details and the low molecular weight soluble carbohydrate composition to get further insight into the adaptation to this uncommon habitat. By means of high pressure freeze fixation, followed by freeze substitution, we could detect an up to 2-µm-thick cell wall surrounded by a distinct layer of extracellular polymeric substances (EPS), likely responsible for the adhering capacities of Tsunamia. The central position of the nucleus and multilobed parietal chloroplast, already observed by light microscopy, could be confirmed. The ultrastructure revealed large electron-dense bodies (EB) in the central cytoplasm, likely resembling degradation products of the chloroplast. Interestingly, these structures contained phosphorous and cobalt, and iron was found in smaller rounded electron-dense bodies by electron energy loss spectroscopy (EELS). Accumulation of these elements suggests a high biosorption activity of Tsunamia. Liquid chromatography-mass spectrometry (LC-MS) data showed the presence of two heterosides (floridoside and digeneaside) together with the polyol sorbitol, which are known as organic osmolytes and compatible solutes. Taken together, these are the first observations on ultrastructural details, element storage and accumulation of protective compounds are contributing to our understanding of the ultrastructural and osmotic solute basis for the ability of Tsunamia to thrive on plastic surfaces.
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Affiliation(s)
- Andreas Holzinger
- Department of Botany, Functional Plant Biology, University of Innsbruck, 6020, Innsbruck, Austria.
| | - Sabrina Obwegeser
- Department of Botany, Functional Plant Biology, University of Innsbruck, 6020, Innsbruck, Austria
| | - Ancuela Andosch
- Department of Biosciences, University of Salzburg, 5020, Salzburg, Austria
| | - Ulf Karsten
- Institute of Biological Sciences, University of Rostock, Rostock, Germany
| | | | - Wolfgang Ruth
- Institute of Chemistry, University of Rostock, Rostock, Germany
| | | | | | - Ursula Lütz-Meindl
- Department of Biosciences, University of Salzburg, 5020, Salzburg, Austria
| | - John A West
- School of BioSciences, University of Melbourne, Parkville, VIC, 3010, Australia
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Arifin AJ, Correa RJ, Goodman CD, Laba J, Dinniwell RE, Palma DA, Nguyen TK. Remote Contouring and Virtual Review During the COVID-19 Pandemic (RECOVR-COVID19): Results of a Quality Improvement Initiative for Virtual Resident Training in Radiation Oncology. Int J Radiat Oncol Biol Phys 2021. [PMCID: PMC8325939 DOI: 10.1016/j.ijrobp.2021.05.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Goodman CD, Correa RJ, Arifin AJ, Dinniwell RE, Laba JM, Nguyen TK. A Framework for Assuring the Safety, Training, Evaluation, and Wellness of Radiation Oncology Residents During the COVID-19 Pandemic (ASTEROiD-COVID19). Adv Radiat Oncol 2021; 6:100754. [PMID: 34307965 PMCID: PMC8285368 DOI: 10.1016/j.adro.2021.100754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 06/26/2021] [Accepted: 07/07/2021] [Indexed: 01/12/2023] Open
Abstract
As the coronavirus disease 2019 (COVID-19) pandemic continues to disrupt nearly all facets of daily life, residency programs must ensure the safety and wellness of their residents while maintaining a commitment to their training and advancement. In addition to standard clinical training, radiation oncology residency programs integrate highly specialized elements specific to the delivery of radiation therapy. Few publications have addressed the significant effects of the pandemic on medical training and even fewer have addressed concerns specific to radiation oncology. We report our experience developing a resident-led adaptation of our training program in response to the COVID-19 pandemic with the aim of assisting other programs to meet this challenge.
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Affiliation(s)
- Christopher D. Goodman
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Rohann J.M. Correa
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Andrew J. Arifin
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Robert E. Dinniwell
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Joanna M. Laba
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Timothy K. Nguyen
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
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10
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Bailey BL, Nguyen W, Ngo A, Goodman CD, Gancheva MR, Favuzza P, Sanz LM, Gamo FJ, Lowes KN, McFadden GI, Wilson DW, Laleu B, Brand S, Jackson PF, Cowman AF, Sleebs BE. Optimisation of 2-(N-phenyl carboxamide) triazolopyrimidine antimalarials with moderate to slow acting erythrocytic stage activity. Bioorg Chem 2021; 115:105244. [PMID: 34452759 DOI: 10.1016/j.bioorg.2021.105244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 07/02/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 11/25/2022]
Abstract
Malaria is a devastating parasitic disease caused by parasites from the genus Plasmodium. Therapeutic resistance has been reported against all clinically available antimalarials, threatening our ability to control the disease and therefore there is an ongoing need for the development of novel antimalarials. Towards this goal, we identified the 2-(N-phenyl carboxamide) triazolopyrimidine class from a high throughput screen of the Janssen Jumpstarter library against the asexual stages of the P. falciparum parasite. Here we describe the structure activity relationship of the identified class and the optimisation of asexual stage activity while maintaining selectivity against the human HepG2 cell line. The most potent analogues from this study were shown to exhibit equipotent activity against P. falciparum multidrug resistant strains and P. knowlesi asexual parasites. Asexual stage phenotyping studies determined the triazolopyrimidine class arrests parasites at the trophozoite stage, but it is likely these parasites are still metabolically active until the second asexual cycle, and thus have a moderate to slow onset of action. Non-NADPH dependent degradation of the central carboxamide and low aqueous solubility was observed in in vitro ADME profiling. A significant challenge remains to correct these liabilities for further advancement of the 2-(N-phenyl carboxamide) triazolopyrimidine scaffold as a potential moderate to slow acting partner in a curative or prophylactic antimalarial treatment.
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Affiliation(s)
- Brodie L Bailey
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - William Nguyen
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Anna Ngo
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia
| | | | - Maria R Gancheva
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Paola Favuzza
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Laura M Sanz
- Global Health Pharma Research Unit, GlaxoSmithKline, Tres Cantos 28760, Spain
| | | | - Kym N Lowes
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Geoffrey I McFadden
- School of Biosciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia; Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004, Australia
| | - Benoît Laleu
- Medicines for Malaria Venture, Geneva 1215, Switzerland
| | - Stephen Brand
- Medicines for Malaria Venture, Geneva 1215, Switzerland
| | - Paul F Jackson
- Global Public Health, Janssen Pharmaceuticals, San Diego, CA, United States
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3010, Australia.
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11
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Chua MJ, Tng J, Hesping E, Fisher GM, Goodman CD, Skinner-Adams T, Do D, Lucke AJ, Reid RC, Fairlie DP, Andrews KT. Histone deacetylase inhibitor AR-42 and achiral analogues kill malaria parasites in vitro and in mice. Int J Parasitol Drugs Drug Resist 2021; 17:118-127. [PMID: 34560571 PMCID: PMC8463797 DOI: 10.1016/j.ijpddr.2021.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 11/29/2022]
Abstract
Malaria is caused by infection with Plasmodium parasites and results in significant health and economic impacts. Malaria eradication is hampered by parasite resistance to current drugs and the lack of a widely effective vaccine. Compounds that target epigenetic regulatory proteins, such as histone deacetylases (HDACs), may lead to new therapeutic agents with a different mechanism of action, thereby avoiding resistance mechanisms to current antimalarial drugs. The anticancer HDAC inhibitor AR-42, as its racemate (rac-AR-42), and 36 analogues were investigated for in vitro activity against P. falciparum. Rac-AR-42 and selected compounds were assessed for cytotoxicity against human cells, histone hyperacetylation, human HDAC1 inhibition and oral activity in a murine malaria model. Rac-AR-42 was tested for ex vivo asexual and in vitro exoerythrocytic stage activity against P. berghei murine malaria parasites. Rac-AR-42 and 13 achiral analogues were potent inhibitors of asexual intraerythrocytic stage P. falciparum 3D7 growth in vitro (IC50 5–50 nM), with four of these compounds having >50-fold selectivity for P. falciparum versus human cells (selectivity index 56–118). Rac-AR-42 induced in situ hyperacetylation of P. falciparum histone H4, consistent with PfHDAC(s) inhibition. Furthermore, rac-AR-42 potently inhibited P. berghei infected erythrocyte growth ex vivo (IC50 40 nM) and P. berghei exoerythrocytic forms in hepatocytes (IC50 1 nM). Oral administration of rac-AR-42 and two achiral analogues inhibited P. berghei growth in mice, with rac-AR-42 (50 mg/kg/day single dose for four days) curing all infections. These findings demonstrate curative properties for HDAC inhibitors in the oral treatment of experimental mouse malaria. HDAC inhibitors rac-AR-42 and 13 analogues inhibit P. falciparum growth in vitro. Rac-AR-42 inhibits P. berghei exoerythrocytic forms in hepatocytes (IC50 1 nM). Rac-AR-42 causes in situ hyperacetylation of P. falciparum histone H4. Rac-AR-42 cures P. berghei infected mice with oral dosing.
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Affiliation(s)
- Ming Jang Chua
- Griffith Institute for Drug Discovery, Griffith University, Queensland, 4111, Australia
| | - Jiahui Tng
- Institute for Molecular Bioscience, The University of Queensland, Queensland, 4072, Australia
| | - Eva Hesping
- Griffith Institute for Drug Discovery, Griffith University, Queensland, 4111, Australia
| | - Gillian M Fisher
- Griffith Institute for Drug Discovery, Griffith University, Queensland, 4111, Australia
| | | | - Tina Skinner-Adams
- Griffith Institute for Drug Discovery, Griffith University, Queensland, 4111, Australia
| | - Darren Do
- Institute for Molecular Bioscience, The University of Queensland, Queensland, 4072, Australia
| | - Andrew J Lucke
- Institute for Molecular Bioscience, The University of Queensland, Queensland, 4072, Australia
| | - Robert C Reid
- Institute for Molecular Bioscience, The University of Queensland, Queensland, 4072, Australia
| | - David P Fairlie
- Institute for Molecular Bioscience, The University of Queensland, Queensland, 4072, Australia.
| | - Katherine T Andrews
- Griffith Institute for Drug Discovery, Griffith University, Queensland, 4111, Australia.
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12
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Goodman CD, Mendez LC, Velker V, Weiss Y, Leung E, Louie AV, Warner A, Hajdok G, D'Souza DP. 3D image-guided interstitial brachytherapy for primary vaginal cancer: A multi-institutional experience. Gynecol Oncol 2020; 160:134-139. [PMID: 33162177 DOI: 10.1016/j.ygyno.2020.10.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/16/2020] [Indexed: 02/02/2023]
Abstract
PURPOSE/OBJECTIVES High dose rate (HDR) interstitial brachytherapy (ISBT) boost is integral for definitive radiation treatment of primary vaginal cancer. Technological advances with CT or MRI guidance provide improved precision and ability to treat more extensively invasive tumors over historical techniques, but reported experience is limited. We sought to provide updated outcome and toxicity data for women with primary vaginal cancer undergoing treatment with a modern ISBT technique. MATERIAL/METHODS Databases of primary vaginal carcinoma patients treated at two Canadian academic cancer institutions were combined including patient, tumor and treatment characteristics, and survival outcomes and toxicity data. Descriptive statistics, survival estimates based on the Kaplan-Meier method, and univariable/multivariable Cox proportional hazards regression analyses are reported. RESULTS Between 2002 and 2017, 67 women with primary vaginal cancer were treated with 3D HDR ISBT. FIGO stage distribution was I (22.4%), II (50.8%), III (17.9%), IVa (9.0%). All patients received external beam radiotherapy and HDR ISBT of 500-750 cGy per fraction over 2-4 fractions. Median follow-up was 2.68 years (95% confidence interval: 2.04-6.04). Cumulative rate of grade 3-4 genitourinary/gastrointestinal toxicity was 10.4%. Four patients developed vaginal fistula. Progression-free survival at 2 and 3 years was 73.5% and 66.4% for all patients, 78.3% and 75.0% for stage I-II and 61.6% and 46.2% for stage III-IVa, respectively (log-rank p = 0.252). CONCLUSIONS Use of 3D image-guided HDR ISBT boost was safe and resulted in improved survival outcomes compared to historical rates in this series of primary vaginal cancer patients. Prospective study is warranted to better define clinical and dosimetric predictors of local control.
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Affiliation(s)
- Christopher D Goodman
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Lucas C Mendez
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Vikram Velker
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Yonatan Weiss
- Department of Radiation Oncology, Odette Cancer Centre, Toronto, Ontario, Canada
| | - Eric Leung
- Department of Radiation Oncology, Odette Cancer Centre, Toronto, Ontario, Canada
| | - Alexander V Louie
- Department of Radiation Oncology, Odette Cancer Centre, Toronto, Ontario, Canada
| | - Andrew Warner
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada.
| | - George Hajdok
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - David P D'Souza
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada.
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13
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Burns AL, Sleebs BE, Siddiqui G, De Paoli AE, Anderson D, Liffner B, Harvey R, Beeson JG, Creek DJ, Goodman CD, McFadden GI, Wilson DW. Retargeting azithromycin analogues to have dual-modality antimalarial activity. BMC Biol 2020; 18:133. [PMID: 32993629 PMCID: PMC7526119 DOI: 10.1186/s12915-020-00859-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/28/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Resistance to front-line antimalarials (artemisinin combination therapies) is spreading, and development of new drug treatment strategies to rapidly kill Plasmodium spp. malaria parasites is urgently needed. Azithromycin is a clinically used macrolide antibiotic proposed as a partner drug for combination therapy in malaria, which has also been tested as monotherapy. However, its slow-killing 'delayed-death' activity against the parasite's apicoplast organelle and suboptimal activity as monotherapy limit its application as a potential malaria treatment. Here, we explore a panel of azithromycin analogues and demonstrate that chemical modifications can be used to greatly improve the speed and potency of antimalarial action. RESULTS Investigation of 84 azithromycin analogues revealed nanomolar quick-killing potency directed against the very earliest stage of parasite development within red blood cells. Indeed, the best analogue exhibited 1600-fold higher potency than azithromycin with less than 48 hrs treatment in vitro. Analogues were effective against zoonotic Plasmodium knowlesi malaria parasites and against both multi-drug and artemisinin-resistant Plasmodium falciparum lines. Metabolomic profiles of azithromycin analogue-treated parasites suggested activity in the parasite food vacuole and mitochondria were disrupted. Moreover, unlike the food vacuole-targeting drug chloroquine, azithromycin and analogues were active across blood-stage development, including merozoite invasion, suggesting that these macrolides have a multi-factorial mechanism of quick-killing activity. The positioning of functional groups added to azithromycin and its quick-killing analogues altered their activity against bacterial-like ribosomes but had minimal change on 'quick-killing' activity. Apicoplast minus parasites remained susceptible to both azithromycin and its analogues, further demonstrating that quick-killing is independent of apicoplast-targeting, delayed-death activity. CONCLUSION We show that azithromycin and analogues can rapidly kill malaria parasite asexual blood stages via a fast action mechanism. Development of azithromycin and analogues as antimalarials offers the possibility of targeting parasites through both a quick-killing and delayed-death mechanism of action in a single, multifactorial chemotype.
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Affiliation(s)
- Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Brad E Sleebs
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3050, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3050, Australia
| | - Ghizal Siddiqui
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Amanda E De Paoli
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Dovile Anderson
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Benjamin Liffner
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Richard Harvey
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, 3004, Australia
- Department of Medicine, University of Melbourne, Melbourne, Australia
- Central Clinical School and Department of Microbiology, Monash University, Melbourne, Australia
| | - Darren J Creek
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Christopher D Goodman
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Geoffrey I McFadden
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia.
- Burnet Institute, Melbourne, Victoria, 3004, Australia.
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14
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Mutsaers A, Boldt G, Goodman CD, Nguyen TK. 161: Improving Patient Communication Among Oncology Trainees: A Systematic Review of Communication Interventions. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(20)31053-7] [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: 11/16/2022]
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15
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Goodman CD, Uddin T, Spillman NJ, McFadden GI. A single point mutation in the Plasmodium falciparum FtsH1 metalloprotease confers actinonin resistance. eLife 2020; 9:58629. [PMID: 32678064 PMCID: PMC7386903 DOI: 10.7554/elife.58629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/17/2020] [Indexed: 11/24/2022] Open
Abstract
The antibiotic actinonin kills malaria parasites (Plasmodium falciparum) by interfering with apicoplast function. Early evidence suggested that actinonin inhibited prokaryote-like post-translational modification in the apicoplast; mimicking its activity against bacteria. However, Amberg Johnson et al. (2017) identified the metalloprotease TgFtsH1 as the target of actinonin in the related parasite Toxoplasma gondii and implicated P. falciparum FtsH1 as a likely target in malaria parasites. The authors were not, however, able to recover actinonin resistant malaria parasites, leaving the specific target of actinonin uncertain. We generated actinonin resistant P. falciparum by in vitro selection and identified a specific sequence change in PfFtsH1 associated with resistance. Introduction of this point mutation using CRISPr-Cas9 allelic replacement was sufficient to confer actinonin resistance in P. falciparum. Our data unequivocally identify PfFtsH1 as the target of actinonin and suggests that actinonin should not be included in the highly valuable collection of ‘irresistible’ drugs for combatting malaria.
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Affiliation(s)
| | - Taher Uddin
- School of BioSciences, University of Melbourne, Parkville, Australia
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16
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Goodman CD, Nijman SF, Senan S, Nossent EJ, Ryerson CJ, Dhaliwal I, Qu XM, Laba J, Rodrigues GB, Palma DA. A Primer on Interstitial Lung Disease and Thoracic Radiation. J Thorac Oncol 2020; 15:902-913. [DOI: 10.1016/j.jtho.2020.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 02/05/2020] [Accepted: 02/11/2020] [Indexed: 12/25/2022]
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17
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Goodman CD, Fakir H, Pautler S, Chin J, Bauman GS. Dosimetric Evaluation of PSMA PET-Delineated Dominant Intraprostatic Lesion Simultaneous Infield Boosts. Adv Radiat Oncol 2020; 5:212-220. [PMID: 32280821 PMCID: PMC7136625 DOI: 10.1016/j.adro.2019.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 08/30/2019] [Accepted: 09/18/2019] [Indexed: 02/07/2023] Open
Abstract
PURPOSE Prostate cancer is multifocal. However, there often exists a single dominant focus in the gland responsible for driving the biology of the disease. Dose escalation to the dominant lesion is a proposed strategy to increase tumor control. We applied radiobiological modeling to evaluate the dosimetric feasibility and benefit of dominant intraprostatic lesion simultaneous in-field boosts (DIL-SIB) to the gross tumor volume (GTV), defined using a novel molecular positron emission tomography (PET) probe (18F-DCFPyL) directed against prostate specific membrane antigen (PSMA). METHODS AND MATERIALS Patients with clinically localized, biopsy-proven prostate cancer underwent preoperative [18F]-DCFPyL PET/computed tomography (CT). DIL-SIB plans were generated by importing the PET/CT into the RayStation treatment planning system. GTV-PET for the DIL-SIB was defined by the highest %SUVmax (percentage of maximum standardized uptake value) that generated a biologically plausible volume. Volumetric arc-based plans incorporating prostate plus DIL-SIB treatment were generated. Tumor control probability (TCP) and normal tissue complication probability (NTCP) with fractionation schemes and boost doses specified in the FLAME (Investigate the Benefit of a Focal Lesion Ablative Microboost in Prostate Cancer; NCT01168479), PROFIT (Prostate Fractionated Irradiation Trial; NCT00304759), PACE (Prostate Advances in Comparative Evidence; NCT01584258), and hypoFLAME (Hypofractionated Focal Lesion Ablative Microboost in prostatE Cancer 2.0; NCT02853110) protocols were compared. RESULTS Comparative DIL-SIB plans for 6 men were generated from preoperative [18F]-DCFPyL PET/CT. Median boost GTV volume was 1.015 cm3 (0.42-1.83 cm3). Median minimum (D99%) DIL-SIB dose for F35BS, F20BS, F5BS, and F5BSH were 97.3 Gy, 80.8 Gy, 46.5 Gy, and 51.5Gy. TCP within the GTV ranged from 84% to 88% for the standard plan and 95% to 96% for the DIL-SIB plans. Within the rest of the prostate, TCP ranged from 89% to 91% for the standard plans and 90% to 92% for the DIL-SIB plans. NTCP for the rectum NTCP was similar for the DIL-SIB plans (0.3%-2.7%) compared with standard plans (0.7%-2.6%). Overall, DIL-SIB plans yielded higher uncomplicated TCP (NTCP, 90%-94%) versus standard plans (NTCP, 83%-85%). CONCLUSIONS PSMA PET provides a novel approach to define GTV for SIB-DIL dose escalation. Work is ongoing to validate PSMA PET-delineated GTV through correlation to coregistered postprostatectomy digitized histopathology.
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Affiliation(s)
- Christopher D. Goodman
- Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada
| | - Hatim Fakir
- Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada
| | - Stephen Pautler
- Division of Urology, Department of Surgery and Division of Surgical Oncology, Department of Oncology, Western University, London, Ontario, Canada
| | - Joseph Chin
- Division of Urology, Department of Surgery and Division of Surgical Oncology, Department of Oncology, Western University, London, Ontario, Canada
| | - Glenn S. Bauman
- Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada
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18
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Chen H, Laba JM, Boldt RG, Goodman CD, Palma DA, Senan S, Louie AV. Stereotactic Ablative Radiation Therapy Versus Surgery in Early Lung Cancer: A Meta-analysis of Propensity Score Studies. Int J Radiat Oncol Biol Phys 2018; 101:186-194. [PMID: 29619964 DOI: 10.1016/j.ijrobp.2018.01.064] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/16/2018] [Accepted: 01/22/2018] [Indexed: 12/25/2022]
Abstract
PURPOSE As no completed randomized trials of surgery versus stereotactic ablative radiation therapy (SABR) in patients with early-stage non-small cell lung cancer are available, numerous propensity score studies have attempted to mimic the setting of clinical trials using nonrandomized data. We performed a meta-analysis of propensity score studies comparing SABR and surgery. METHODS AND MATERIALS The MEDLINE and Embase databases were queried up to December 2016. Two authors independently reviewed the records for inclusion and extracted outcome measures. The study was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. The primary meta-analysis and secondary analyses were carried out using R (version 3.3.2) at a significance level of .05. RESULTS Sixteen studies were included in the meta-analysis. Overall survival favored surgery (hazard ratio for SABR vs surgery, 1.48 [95% confidence interval, 1.26-1.72]; I2 = 80.5%). Lung cancer-specific survival was not significantly different between SABR and surgery (hazard ratio, 1.17 [95% confidence interval, 0.92-1.50]; I2 = 18.6%). On stratification, overall survival favored both lobectomy and sublobar resection over SABR, although lung cancer-specific survival was again not significantly different. On secondary analysis, the lymph node upstaging rate was 15.6% following surgery, with 11.4% of patients receiving chemotherapy. The propensity score-matching caliper distance and first-author specialty were found to be associated with survival endpoints on regression. CONCLUSIONS For patients with early-stage non-small cell lung cancer who are eligible for either treatment, better overall survival was seen after surgery compared with SABR. However, lung cancer-specific survival was similar for both treatments. Prospective clinical trials are preferred to propensity analyses in evaluating the nature of non-cancer-related death after SABR.
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Affiliation(s)
- Hanbo Chen
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Joanna M Laba
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - R Gabriel Boldt
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Christopher D Goodman
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - David A Palma
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada
| | - Suresh Senan
- Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands
| | - Alexander V Louie
- Department of Radiation Oncology, London Health Sciences Centre, London, Ontario, Canada.
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19
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Sayers CP, Mollard V, Buchanan HD, McFadden GI, Goodman CD. A genetic screen in rodent malaria parasites identifies five new apicoplast putative membrane transporters, one of which is essential in human malaria parasites. Cell Microbiol 2017; 20. [DOI: 10.1111/cmi.12789] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 09/04/2017] [Accepted: 09/07/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Claire P. Sayers
- School of BioSciences University of Melbourne Parkville Victoria Australia
| | - Vanessa Mollard
- School of BioSciences University of Melbourne Parkville Victoria Australia
| | - Hayley D. Buchanan
- School of BioSciences University of Melbourne Parkville Victoria Australia
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20
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Yeoh LM, Goodman CD, Mollard V, McFadden GI, Ralph SA. Comparative transcriptomics of female and male gametocytes in Plasmodium berghei and the evolution of sex in alveolates. BMC Genomics 2017; 18:734. [PMID: 28923023 PMCID: PMC5604118 DOI: 10.1186/s12864-017-4100-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/31/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The clinical symptoms of malaria are caused by the asexual replication of Plasmodium parasites in the blood of the vertebrate host. To spread to new hosts, however, the malaria parasite must differentiate into sexual forms, termed gametocytes, which are ingested by a mosquito vector. Sexual differentiation produces either female or male gametocytes, and involves significant morphological and biochemical changes. These transformations prepare gametocytes for the rapid progression to gamete formation and fertilisation, which occur within 20 min of ingestion. Here we present the transcriptomes of asexual, female, and male gametocytes in P. berghei, and a comprehensive statistically-based differential-expression analysis of the transcriptional changes that underpin this sexual differentiation. RESULTS RNA-seq analysis revealed numerous differences in the transcriptomes of female and male gametocytes compared to asexual stages. Overall, there is net downregulation of transcripts in gametocytes compared to asexual stages, with this trend more marked in female gametocytes. Our analysis identified transcriptional changes in previously-characterised gametocyte-specific pathways, which validated our approach. We also detected many previously-unreported female- and male-specific pathways and genes. Transcriptional biases in stage and gender were then used to investigate sex-specificity and sexual dimorphism of Plasmodium in an evolutionary context. Sex-related gene expression is well conserved between Plasmodium species, but relatively poorly conserved in related organisms outside this genus. This pattern of conservation is most evident in genes necessary for both male and female gametocyte formation. However, this trend is less pronounced for male-specific genes, which are more highly conserved outside the genus than genes specific to female development. CONCLUSIONS We characterised the transcriptional changes that are integral to the development of the female and male sexual forms of Plasmodium. These differential-expression patterns provide a vital insight into understanding the gender-specific characteristics of this essential stage that is the primary target for treatments that block parasite transmission. Our results also offer insight into the evolution of sex genes through Alveolata, and suggest that many Plasmodium sex genes evolved within the genus. We further hypothesise that male gametocytes co-opted pre-existing cellular machinery in their evolutionary history, whereas female gametocytes evolved more through the development of novel, parasite-specific pathways.
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Affiliation(s)
- Lee M Yeoh
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, 3010, Australia.,School of BioSciences, The University of Melbourne, Parkville, 3010, Australia
| | | | - Vanessa Mollard
- School of BioSciences, The University of Melbourne, Parkville, 3010, Australia
| | - Geoffrey I McFadden
- School of BioSciences, The University of Melbourne, Parkville, 3010, Australia.
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, 3010, Australia.
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21
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Shears MJ, MacRae JI, Mollard V, Goodman CD, Sturm A, Orchard LM, Llinás M, McConville MJ, Botté CY, McFadden GI. Characterization of the Plasmodium falciparum and P. berghei glycerol 3-phosphate acyltransferase involved in FASII fatty acid utilization in the malaria parasite apicoplast. Cell Microbiol 2016; 19. [PMID: 27324409 PMCID: PMC5213128 DOI: 10.1111/cmi.12633] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 06/11/2016] [Accepted: 06/17/2016] [Indexed: 12/24/2022]
Abstract
Malaria parasites can synthesize fatty acids via a type II fatty acid synthesis (FASII) pathway located in their apicoplast. The FASII pathway has been pursued as an anti‐malarial drug target, but surprisingly little is known about its role in lipid metabolism. Here we characterize the apicoplast glycerol 3‐phosphate acyltransferase that acts immediately downstream of FASII in human (Plasmodium falciparum) and rodent (Plasmodium berghei) malaria parasites and investigate how this enzyme contributes to incorporating FASII fatty acids into precursors for membrane lipid synthesis. Apicoplast targeting of the P. falciparum and P. berghei enzymes are confirmed by fusion of the N‐terminal targeting sequence to GFP and 3′ tagging of the full length protein. Activity of the P. falciparum enzyme is demonstrated by complementation in mutant bacteria, and critical residues in the putative active site identified by site‐directed mutagenesis. Genetic disruption of the P. falciparum enzyme demonstrates it is dispensable in blood stage parasites, even in conditions known to induce FASII activity. Disruption of the P. berghei enzyme demonstrates it is dispensable in blood and mosquito stage parasites, and only essential for development in the late liver stage, consistent with the requirement for FASII in rodent malaria models. However, the P. berghei mutant liver stage phenotype is found to only partially phenocopy loss of FASII, suggesting newly made fatty acids can take multiple pathways out of the apicoplast and so giving new insight into the role of FASII and apicoplast glycerol 3‐phosphate acyltransferase in malaria parasites.
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Affiliation(s)
- Melanie J Shears
- School of BioSciences, University of Melbourne, VIC 3010, Australia.,Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, 21205, United States
| | - James I MacRae
- The Francis Crick Institute, Metabolomics, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Vanessa Mollard
- School of BioSciences, University of Melbourne, VIC 3010, Australia
| | | | - Angelika Sturm
- School of BioSciences, University of Melbourne, VIC 3010, Australia
| | - Lindsey M Orchard
- Department of Biochemistry and Molecular Biology, Department of Chemistry and Center for Malaria Research, Pennsylvania State University, State College, University Park, PA, 16802, United States
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, Department of Chemistry and Center for Malaria Research, Pennsylvania State University, State College, University Park, PA, 16802, United States
| | - Malcolm J McConville
- Department of Biochemistry and Molecular Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Cyrille Y Botté
- Apicolipid team, Institute for Advanced Biosciences UMR CNRS5309 INSMERM U1209, Université Grenoble Alpes, Grenoble, France
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22
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Lim L, Sayers CP, Goodman CD, McFadden GI. Targeting of a Transporter to the Outer Apicoplast Membrane in the Human Malaria Parasite Plasmodium falciparum. PLoS One 2016; 11:e0159603. [PMID: 27442138 PMCID: PMC4956234 DOI: 10.1371/journal.pone.0159603] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [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: 04/15/2016] [Accepted: 07/05/2016] [Indexed: 01/08/2023] Open
Abstract
Apicoplasts are vestigial plastids in apicomplexan parasites like Plasmodium, the causative agent of malaria. Apicomplexan parasites are dependant on their apicoplasts for synthesis of various molecules that they are unable to scavenge in sufficient quantity from their host, which makes apicoplasts attractive drug targets. Proteins known as plastid phosphate translocators (pPTs) are embedded in the outer apicoplast membrane and are responsible for the import of carbon, energy and reducing power to drive anabolic synthesis in the organelle. We investigated how a pPT is targeted into the outer apicoplast membrane of the human malaria parasite P. falciparum. We showed that a transmembrane domain is likely to act as a recessed signal anchor to direct the protein into the endomembrane system, and that a tyrosine in the cytosolic N-terminus of the protein is essential for targeting, but one or more, as yet unidentified, factors are also essential to direct the protein into the outer apicoplast membrane.
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Affiliation(s)
- Liting Lim
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Claire P. Sayers
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
| | | | - Geoffrey I. McFadden
- School of BioSciences, University of Melbourne, Melbourne, Victoria, Australia
- * E-mail:
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23
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Goodman CD, Siregar JE, Mollard V, Vega-Rodríguez J, Syafruddin D, Matsuoka H, Matsuzaki M, Toyama T, Sturm A, Cozijnsen A, Jacobs-Lorena M, Kita K, Marzuki S, McFadden GI. Parasites resistant to the antimalarial atovaquone fail to transmit by mosquitoes. Science 2016; 352:349-53. [PMID: 27081071 DOI: 10.1126/science.aad9279] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 03/10/2016] [Indexed: 12/16/2022]
Abstract
Drug resistance compromises control of malaria. Here, we show that resistance to a commonly used antimalarial medication, atovaquone, is apparently unable to spread. Atovaquone pressure selects parasites with mutations in cytochrome b, a respiratory protein with low but essential activity in the mammalian blood phase of the parasite life cycle. Resistance mutations rescue parasites from the drug but later prove lethal in the mosquito phase, where parasites require full respiration. Unable to respire efficiently, resistant parasites fail to complete mosquito development, arresting their life cycle. Because cytochrome b is encoded by the maternally inherited parasite mitochondrion, even outcrossing with wild-type strains cannot facilitate spread of resistance. Lack of transmission suggests that resistance will be unable to spread in the field, greatly enhancing the utility of atovaquone in malaria control.
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Affiliation(s)
| | - Josephine E Siregar
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia. Eijkman Institute for Molecular Biology, JI Diponegoro no. 69, Jakarta, 10430, Indonesia. Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Vanessa Mollard
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Joel Vega-Rodríguez
- Johns Hopkins University Bloomberg School of Public Health, Department of Molecular Microbiology and Immunology, Malaria Research Institute, Baltimore, MD 21205, USA
| | - Din Syafruddin
- Eijkman Institute for Molecular Biology, JI Diponegoro no. 69, Jakarta, 10430, Indonesia. Department of Parasitology, Faculty of Medicine, Hasanuddin University, Jalan Perintis Kemerdekaan Km10, Makassar 90245, Indonesia
| | - Hiroyuki Matsuoka
- Division of Medical Zoology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Motomichi Matsuzaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tomoko Toyama
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Angelika Sturm
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Anton Cozijnsen
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Marcelo Jacobs-Lorena
- Johns Hopkins University Bloomberg School of Public Health, Department of Molecular Microbiology and Immunology, Malaria Research Institute, Baltimore, MD 21205, USA
| | - Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. School of Tropical Medicine and Global Health, Nagasaki University, Sakamoto, Nagasaki 852-8523, Japan
| | - Sangkot Marzuki
- Eijkman Institute for Molecular Biology, JI Diponegoro no. 69, Jakarta, 10430, Indonesia
| | - Geoffrey I McFadden
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia.
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24
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Kalanon M, Bargieri D, Sturm A, Matthews K, Ghosh S, Goodman CD, Thiberge S, Mollard V, McFadden GI, Ménard R, Koning‐Ward TF. The
Plasmodium
translocon of exported proteins component EXP2 is critical for establishing a patent malaria infection in mice. Cell Microbiol 2015; 18:399-412. [DOI: 10.1111/cmi.12520] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/26/2015] [Accepted: 08/31/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Ming Kalanon
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
| | - Daniel Bargieri
- Unité de Biologie et Génétique du PaludismeInstitut Pasteur Paris France
- Department of Parasitology, Institute of Biomedical SciencesUniversity of São Paulo São Paulo SP Brazil
| | - Angelika Sturm
- School of BioSciencesThe University of Melbourne Parkville Victoria 3010 Australia
| | - Kathryn Matthews
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
| | - Sreejoyee Ghosh
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
| | | | - Sabine Thiberge
- Unité de Biologie et Génétique du PaludismeInstitut Pasteur Paris France
| | - Vanessa Mollard
- School of BioSciencesThe University of Melbourne Parkville Victoria 3010 Australia
| | - Geoffrey I. McFadden
- School of BioSciencesThe University of Melbourne Parkville Victoria 3010 Australia
| | - Robert Ménard
- Unité de Biologie et Génétique du PaludismeInstitut Pasteur Paris France
| | - Tania F. Koning‐Ward
- Molecular and Medical Research Unit, School of MedicineDeakin University Waurn Ponds Geelong Victoria 3216 Australia
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25
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Wilson DW, Goodman CD, Sleebs BE, Weiss GE, de Jong NW, Angrisano F, Langer C, Baum J, Crabb BS, Gilson PR, McFadden GI, Beeson JG. Macrolides rapidly inhibit red blood cell invasion by the human malaria parasite, Plasmodium falciparum. BMC Biol 2015; 13:52. [PMID: 26187647 PMCID: PMC4506589 DOI: 10.1186/s12915-015-0162-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria invasion of red blood cells involves multiple parasite-specific targets that are easily accessible to inhibitory compounds, making it an attractive target for antimalarial development. However, no current antimalarial agents act against host cell invasion. RESULTS Here, we demonstrate that the clinically used macrolide antibiotic azithromycin, which is known to kill human malaria asexual blood-stage parasites by blocking protein synthesis in their apicoplast, is also a rapid inhibitor of red blood cell invasion in human (Plasmodium falciparum) and rodent (P. berghei) malarias. Multiple lines of evidence demonstrate that the action of azithromycin in inhibiting parasite invasion of red blood cells is independent of its inhibition of protein synthesis in the parasite apicoplast, opening up a new strategy to develop a single drug with multiple parasite targets. We identified derivatives of azithromycin and erythromycin that are better invasion inhibitors than parent compounds, offering promise for development of this novel antimalarial strategy. CONCLUSIONS Safe and effective macrolide antibiotics with dual modalities could be developed to combat malaria and reduce the parasite's options for resistance.
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Affiliation(s)
- Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia. .,Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Christopher D Goodman
- Plant Cell Biology Research Centre, School of Biosciences, University of Melbourne, Parkville, Victoria, 3010, Australia.
| | - Brad E Sleebs
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia.
| | - Greta E Weiss
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Nienke Wm de Jong
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Fiona Angrisano
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Department of Life Sciences, Imperial College London, South Kensington, London, SW7 2AZ, UK.
| | - Christine Langer
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia.
| | - Jake Baum
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Department of Life Sciences, Imperial College London, South Kensington, London, SW7 2AZ, UK.
| | - Brendan S Crabb
- Department of Medical Biology, University of Melbourne, Parkville, Victoria, 3050, Australia. .,Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia. .,Department of Immunology, Monash University, Clayton, Victoria, 3800, Australia.
| | - Paul R Gilson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia. .,Department of Immunology, Monash University, Clayton, Victoria, 3800, Australia.
| | - Geoffrey I McFadden
- Plant Cell Biology Research Centre, School of Biosciences, University of Melbourne, Parkville, Victoria, 3010, Australia.
| | - James G Beeson
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3050, Australia. .,Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, 3004, Australia. .,Department of Microbiology, Monash University, Clayton, Victoria, 3168, Australia.
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26
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Yeoh LM, Goodman CD, Hall NE, van Dooren GG, McFadden GI, Ralph SA. A serine-arginine-rich (SR) splicing factor modulates alternative splicing of over a thousand genes in Toxoplasma gondii. Nucleic Acids Res 2015; 43:4661-75. [PMID: 25870410 PMCID: PMC4482073 DOI: 10.1093/nar/gkv311] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 03/27/2015] [Indexed: 11/12/2022] Open
Abstract
Single genes are often subject to alternative splicing, which generates alternative mature mRNAs. This phenomenon is widespread in animals, and observed in over 90% of human genes. Recent data suggest it may also be common in Apicomplexa. These parasites have small genomes, and economy of DNA is evolutionarily favoured in this phylum. We investigated the mechanism of alternative splicing in Toxoplasma gondii, and have identified and localized TgSR3, a homologue of ASF/SF2 (alternative-splicing factor/splicing factor 2, a serine-arginine–rich, or SR protein) to a subnuclear compartment. In addition, we conditionally overexpressed this protein, which was deleterious to growth. qRT-PCR was used to confirm perturbation of splicing in a known alternatively-spliced gene. We performed high-throughput RNA-seq to determine the extent of splicing modulated by this protein. Current RNA-seq algorithms are poorly suited to compact parasite genomes, and hence we complemented existing tools by writing a new program, GeneGuillotine, that addresses this deficiency by segregating overlapping reads into distinct genes. In order to identify the extent of alternative splicing, we released another program, JunctionJuror, that detects changes in intron junctions. Using this program, we identified about 2000 genes that were constitutively alternatively spliced in T. gondii. Overexpressing the splice regulator TgSR3 perturbed alternative splicing in over 1000 genes.
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Affiliation(s)
- Lee M Yeoh
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Christopher D Goodman
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Nathan E Hall
- Department of Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia Life Sciences Computation Centre, Victorian Life Sciences Computation Initiative, Carlton, Victoria 3010, Australia
| | - Giel G van Dooren
- Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Geoffrey I McFadden
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
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27
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Goodman CD, McFadden GI. Ycf93 (Orf105), a small apicoplast-encoded membrane protein in the relict plastid of the malaria parasite Plasmodium falciparum that is conserved in Apicomplexa. PLoS One 2014; 9:e91178. [PMID: 24705170 PMCID: PMC3976246 DOI: 10.1371/journal.pone.0091178] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 02/10/2014] [Indexed: 11/27/2022] Open
Abstract
Malaria parasites retain a relict plastid (apicoplast) from a photosynthetic ancestor shared with dinoflagellate algae. The apicoplast is a useful drug target; blocking housekeeping pathways such as genome replication and translation in the organelle kills parasites and protects against malaria. The apicoplast of Plasmodium falciparum encodes 30 proteins and a suite of rRNAs and tRNAs that facilitate their expression. orf105 is a hypothetical apicoplast gene that would encode a small protein (PfOrf105) with a predicted C-terminal transmembrane domain. We produced antisera to a predicted peptide within PfOrf105. Western blot analysis confirmed expression of orf105 and immunofluorescence localised the gene product to the apicoplast. Pforf105 encodes a membrane protein that has an apparent mass of 17.5 kDa and undergoes substantial turnover during the 48-hour asexual life cycle of the parasite in blood stages. The effect of actinonin, an antimalarial with a putative impact on post-translational modification of apicoplast proteins like PfOrf105, was examined. Unlike other drugs perturbing apicoplast housekeeping that induce delayed death, actinonin kills parasites immediately and has an identical drug exposure phenotype to the isopentenyl diphosphate synthesis blocker fosmidomycin. Open reading frames of similar size to PfOrf105, which also have predicted C-terminal trans membrane domains, occur in syntenic positions in all sequenced apicoplast genomes from Phylum Apicomplexa. We therefore propose to name these genes ycf93 (hypothetical chloroplast reading frame 93) according to plastid gene nomenclature convention for conserved proteins of unknown function.
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Affiliation(s)
| | - Geoffrey I. McFadden
- School of Botany, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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28
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Goodman CD, Mollard V, Louie T, Holloway GA, Watson KG, McFadden GI. Apicoplast acetyl Co-A carboxylase of the human malaria parasite is not targeted by cyclohexanedione herbicides. Int J Parasitol 2014; 44:285-9. [DOI: 10.1016/j.ijpara.2014.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 12/22/2013] [Accepted: 01/07/2014] [Indexed: 10/25/2022]
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29
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Marchal E, Smithen DA, Uddin MI, Robertson AW, Jakeman DL, Mollard V, Goodman CD, MacDougall KS, McFarland SA, McFadden GI, Thompson A. Synthesis and antimalarial activity of prodigiosenes. Org Biomol Chem 2014; 12:4132-42. [DOI: 10.1039/c3ob42548g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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30
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Matthews K, Kalanon M, Chisholm SA, Sturm A, Goodman CD, Dixon MWA, Sanders PR, Nebl T, Fraser F, Haase S, McFadden GI, Gilson PR, Crabb BS, de Koning-Ward TF. The Plasmodium translocon of exported proteins (PTEX) component thioredoxin-2 is important for maintaining normal blood-stage growth. Mol Microbiol 2013; 89:1167-86. [PMID: 23869529 DOI: 10.1111/mmi.12334] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2013] [Indexed: 11/30/2022]
Abstract
Plasmodium parasites remodel their vertebrate host cells by translocating hundreds of proteins across an encasing membrane into the host cell cytosol via a putative export machinery termed PTEX. Previously PTEX150, HSP101 and EXP2 have been shown to be bona fide members of PTEX. Here we validate that PTEX88 and TRX2 are also genuine members of PTEX and provide evidence that expression of PTEX components are also expressed in early gametocytes, mosquito and liver stages, consistent with observations that protein export is not restricted to asexual stages. Although amenable to genetic tagging, HSP101, PTEX150, EXP2 and PTEX88 could not be genetically deleted in Plasmodium berghei, in keeping with the obligatory role this complex is postulated to have in maintaining normal blood-stage growth. In contrast, the putative thioredoxin-like protein TRX2 could be deleted, with knockout parasites displaying reduced grow-rates, both in vivo and in vitro, and reduced capacity to cause severe disease in a cerebral malaria model. Thus, while not essential for parasite survival, TRX2 may help to optimize PTEX activity. Importantly, the generation of TRX2 knockout parasites that display altered phenotypes provides a much-needed tool to dissect PTEX function.
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Affiliation(s)
- Kathryn Matthews
- School of Medicine, Deakin University, Waurn Ponds, Vic., 3216, Australia
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31
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Abstract
INTRODUCTION The relict plastid, or apicoplast, is a characteristic feature of Plasmodium spp. and reflects the unusual evolutionary origins of these parasites. The essential role this organelle plays in the life of the parasite, and its unusual, non-mammalian metabolism, make the apicoplast an excellent drug target. AREAS COVERED This review focuses on the biological role of the apicoplast in the erythrocytic life cycle and what that reveals about existing drug targets. We also discuss the future of the apicoplast in the development of anti-malarials, emphasizing those pathways with greatest potential as a source of novel drug targets and emphasizing the need to understand in vitro drug responses to optimize eventual use of these drugs to treat malaria. EXPERT OPINION More than a decade of research on the apicoplast has confirmed the promise of this organelle as a source of drug targets. It is now possible to rationally assess the value of existing drugs and new drug targets, and to understand the role these drugs can play in the arsenal of anti-malarial treatments.
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Affiliation(s)
- Christopher D Goodman
- University of Melbourne, School of Botany, Professor's Walk, Parkville, Vic, 3010, Australia.
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32
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Jackson KE, Pham JS, Kwek M, De Silva NS, Allen SM, Goodman CD, McFadden GI, Ribas de Pouplana L, Ralph SA. Dual targeting of aminoacyl-tRNA synthetases to the apicoplast and cytosol in Plasmodium falciparum. Int J Parasitol 2012; 42:177-86. [DOI: 10.1016/j.ijpara.2011.11.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 11/22/2011] [Accepted: 11/23/2011] [Indexed: 11/16/2022]
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33
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Nair SC, Brooks CF, Goodman CD, Sturm A, Strurm A, McFadden GI, Sundriyal S, Anglin JL, Song Y, Moreno SNJ, Striepen B. Apicoplast isoprenoid precursor synthesis and the molecular basis of fosmidomycin resistance in Toxoplasma gondii. ACTA ACUST UNITED AC 2011; 208:1547-59. [PMID: 21690250 PMCID: PMC3135366 DOI: 10.1084/jem.20110039] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Expression of a bacterial transporter protein in Toxoplasma gondii results in parasite susceptibility to Formidomycin, a drug targeting isoprenoid precursor synthesis. Apicomplexa are important pathogens that include the causative agents of malaria, toxoplasmosis, and cryptosporidiosis. Apicomplexan parasites contain a relict chloroplast, the apicoplast. The apicoplast is indispensable and an attractive drug target. The apicoplast is home to a 1-deoxy-d-xylulose-5-phosphate (DOXP) pathway for the synthesis of isoprenoid precursors. This pathway is believed to be the most conserved function of the apicoplast, and fosmidomycin, a specific inhibitor of the pathway, is an effective antimalarial. Surprisingly, fosmidomycin has no effect on most other apicomplexans. Using Toxoplasma gondii, we establish that the pathway is essential in parasites that are highly fosmidomycin resistant. We define the molecular basis of resistance and susceptibility, experimentally testing various host and parasite contributions in T. gondii and Plasmodium. We demonstrate that in T. gondii the parasite plasma membrane is a critical barrier to drug uptake. In strong support of this hypothesis, we engineer de novo drug-sensitive T. gondii parasites by heterologous expression of a bacterial transporter protein. Mice infected with these transgenic parasites can now be cured from a lethal challenge with fosmidomycin. We propose that the varied extent of metabolite exchange between host and parasite is a crucial determinator of drug susceptibility and a predictor of future resistance.
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Affiliation(s)
- Sethu C Nair
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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34
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Johnson RA, McFadden GI, Goodman CD. Characterization of two malaria parasite organelle translation elongation factor G proteins: the likely targets of the anti-malarial fusidic acid. PLoS One 2011; 6:e20633. [PMID: 21695207 PMCID: PMC3112199 DOI: 10.1371/journal.pone.0020633] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 05/06/2011] [Indexed: 11/18/2022] Open
Abstract
Malaria parasites harbour two organelles with bacteria-like metabolic processes that are the targets of many anti-bacterial drugs. One such drug is fusidic acid, which inhibits the translation component elongation factor G. The response of P. falciparum to fusidic acid was characterised using extended SYBR-Green based drug trials. This revealed that fusidic acid kills in vitro cultured P. falciparum parasites by immediately blocking parasite development. Two bacterial-type protein translation elongation factor G genes are identified as likely targets of fusidic acid. Sequence analysis suggests that these proteins function in the mitochondria and apicoplast and both should be sensitive to fusidic acid. Microscopic examination of protein-reporter fusions confirm the prediction that one elongation factor G is a component of parasite mitochondria whereas the second is a component of the relict plastid or apicoplast. The presence of two putative targets for a single inhibitory compound emphasizes the potential of elongation factor G as a drug target in malaria.
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Affiliation(s)
- Russell A. Johnson
- Plant Cell Biology Research Centre-School of Botany, University of Melbourne, Parkville, Victoria, Australia
| | - Geoffrey I. McFadden
- Plant Cell Biology Research Centre-School of Botany, University of Melbourne, Parkville, Victoria, Australia
| | - Christopher D. Goodman
- Plant Cell Biology Research Centre-School of Botany, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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Gould SB, Kraft LGK, van Dooren GG, Goodman CD, Ford KL, Cassin AM, Bacic A, McFadden GI, Waller RF. Ciliate pellicular proteome identifies novel protein families with characteristic repeat motifs that are common to alveolates. Mol Biol Evol 2010; 28:1319-31. [PMID: 21127172 DOI: 10.1093/molbev/msq321] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The pellicles of alveolates (ciliates, apicomplexans, and dinoflagellates) share a common organization, yet perform very divergent functions, including motility, host cell invasion, and armor. The alveolate pellicle consists of a system of flattened membrane sacs (alveoli, which are the defining feature of the group) below the plasma membrane that is supported by a membrane skeleton as well as a network of microtubules and other filamentous elements. We recently showed that a family of proteins, alveolins, are common and unique to this pellicular structure in alveolates. To identify additional proteins that contribute to this structure, a pellicle proteome study was conducted for the ciliate Tetrahymena thermophila. We found 1,173 proteins associated with this structure, 45% (529 proteins) of which represented novel proteins without matches to other functionally characterized proteins. Expression of four newly identified T. thermophila pellicular proteins as green fluorescent protein-fusion constructs confirmed pellicular location, and one new protein located in the oral apparatus. Bioinformatic analysis revealed that 21% of the putative pellicular proteins, predominantly the novel proteins, contained highly repetitive regions with strong amino acid biases for particular residues (K, E, Q, L, I, and V). When the T. thermophila novel proteins were compared with apicomplexan genomic data, 278 proteins with high sequence similarity were identified, suggesting that many of these putative pellicular components are shared between the alveolates. Of these shared proteins, 126 contained the distinctive repeat regions. Localization of two such proteins in Toxoplasma gondii confirmed their role in the pellicle and in doing so identified two new proteins of the apicomplexan invasive structure--the apical complex. Screening broadly for these repetitive domains in genomic data revealed large and actively evolving families of such proteins in alveolates, suggesting that these proteins might underpin the diversity and utility of their unique pellicular structure.
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Affiliation(s)
- Sven B Gould
- School of Botany, University of Melbourne, Victoria, Australia.
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Abstract
Fatty acid biosynthesis pathways in protozoan parasites are reviewed with a view to targeting this metabolism for drug therapy. The type II fatty acid biosynthesis pathways derived from bacteria in protozoan relict plastids and mitochondria are examined in different groups with emphasis on apicomplexa. The suitability of different enzymes from the type II fatty acid biosynthesis pathway for drug intervention, and the state-of-play with known and potential inhibitors is explored. The type I acid biosynthesis pathways that occur in select protozoan parasites and their potential for inhibition using anti-tumour and obesity management compounds currently in development are also examined. Pathways used by parasites to scavenge and modify host lipids are also described briefly and their potential for therapeutics discussed.
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Affiliation(s)
- C D Goodman
- School of Botany, University of Melbourne, Parkville, Victoria 3010, Australia.
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Abstract
Apicomplexan parasitic diseases impose devastating impacts on much of the world's population. The increasing prevalence of drug resistant parasites and the growing number of immuno-compromised individuals are exacerbating the problem to the point that the need for novel, inexpensive drugs is greater now than ever. Discovery of a prokaryotic, Type II fatty acid synthesis (FAS) pathway associated with the plastid-like organelle (apicoplast) of Plasmodium and Toxoplasma has provided a wealth of novel drug targets. Since this pathway is both essential and fundamentally different from the cytosolic Type I pathway of the human host, apicoplast FAS has tremendous potential for the development of parasite-specific inhibitors. Many components of this pathway are already the target for existing antibiotics and herbicides, which should significantly reduce the time and cost of drug development. Continuing interest--both in the pharmaceutical and herbicide industries--in fatty acid synthesis inhibitors proffers an ongoing stream of potential new anti-parasitic compounds. It has now emerged that not all apicomplexan parasites have retained the Type II fatty acid biosynthesis pathway. No fatty acid biosynthesis enzymes are encoded in the genome of Theileria annulata or T. parva, suggesting that fatty acid synthesis is lacking in these parasites. The human intestinal parasite Cryptosporidium parvum appears to have lost the apicoplast entirely; instead relying on an unusual cytosolic Type I FAS. Nevertheless, newly developed anti-cancer and anti-obesity drugs targeting human Type I FAS may yet prove efficacious against Cryptosporidium and other apicomplexans that rely on this Type I FAS pathway.
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Affiliation(s)
- C D Goodman
- School of Botany, University of Melbourne, Melbourne, Australia.
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Fujiwara M, Akimune H, Cribier M, Daito I, Ejiri H, Fujimura H, Fujita Y, Goodman CD, Hara K, Harakeh MN, Ihara F, Ishikawa T, Janecke J, Kawabata T, Raghavan RS, Schwarz K, Tanaka M, Yamanaka T, Yosoi M, Zegers RG. Gamow-teller strengths of the inverse beta transition 176Yb-->176Lu for spectroscopy of proton-proton and other sub-MeV solar neutrinos. Phys Rev Lett 2000; 85:4442-4445. [PMID: 11082566 DOI: 10.1103/physrevlett.85.4442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2000] [Indexed: 05/23/2023]
Abstract
Discrete Gamow-Teller (GT) transitions 176Yb-->176Lu at low excitation energies have been measured via the ( 3He,t) reaction at 450 MeV and at 0 degrees. For 176Yb, two low-lying states are observed, setting low thresholds Q(nu) = 301 and 445 keV for neutrino ( nu) capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q(nu) in Yb-Lu indicate that Yb-based nu detectors are well suited for a direct measurement of the sub-MeV solar electron-neutrino ( nu(e)) spectrum including pp neutrinos.
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Affiliation(s)
- M Fujiwara
- Research Center for Nuclear Physics, Osaka University, Mihogaoka 10-1, Ibaraki, Osaka 657-0047, Japan and Advanced Science Research Center, JAERI, Tokai, Ibaraki, 319-1195 Japan
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Bhattacharya M, Goodman CD, Raghavan RS, Palarczyk M, Garcia A, Rapaport J, Zupranski P. Measurement of gamow-teller strength for 176Yb --> 176Lu and the efficiency of a solar neutrino detector. Phys Rev Lett 2000; 85:4446-4449. [PMID: 11082567 DOI: 10.1103/physrevlett.85.4446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2000] [Indexed: 05/23/2023]
Abstract
We report a 0 degrees 176Yb(p,n)176Lu measurement at IUCF where we used 120 and 160 MeV protons and the energy dependence method to determine Gamow-Teller (GT) matrix elements relative to the model independent Fermi matrix element. The data show that there is an isolated concentration of GT strength in the low-lying 1(+) states making the proposed Low Energy Neutrino Spectroscopy detector (based on neutrino captures on 176Yb) sensitive to pp and 7Be neutrinos and a promising detector to resolve the solar neutrino problem.
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Affiliation(s)
- M Bhattacharya
- Indiana University Cyclotron Facility, Bloomington, Indiana 47408 and University of Notre Dame, Notre Dame, Indiana 46556 and Nuclear Physics Laboratory, University of Washington, Seattle, Washington 98195, USA
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Mueller LA, Goodman CD, Silady RA, Walbot V. AN9, a petunia glutathione S-transferase required for anthocyanin sequestration, is a flavonoid-binding protein. Plant Physiol 2000; 123:1561-70. [PMID: 10938372 PMCID: PMC59113 DOI: 10.1104/pp.123.4.1561] [Citation(s) in RCA: 243] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/1999] [Accepted: 04/21/2000] [Indexed: 05/18/2023]
Abstract
AN9 is a glutathione S-transferase from petunia (Petunia hybrida) required for efficient anthocyanin export from the site of synthesis in the cytoplasm into permanent storage in the vacuole. For many xenobiotics it is well established that a covalent glutathione (GSH) tag mediates recognition of molecules destined for vacuolar sequestration by a tonoplast-localized ATP-binding cassette pump. Here we inquired whether AN9 catalyzes the formation of GSH conjugates with flavonoid substrates. Using high-performance liquid chromatography analysis of reaction mixtures containing enzyme, GSH, and flavonoids, including anthocyanins, we could detect neither conjugates nor a decrease in the free thiol concentration. These results suggest that no conjugate is formed in vitro. However, AN9 was shown to bind flavonoids using three assays: inhibition of the glutathione S-transferase activity of AN9 toward the common substrate 1-chloro 2,4-dinitrobenzene, equilibrium dialysis, and tryptophan quenching. We conclude that AN9 is a flavonoid-binding protein, and propose that in vivo it serves as a cytoplasmic flavonoid carrier protein.
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Affiliation(s)
- L A Mueller
- Department of Biological Sciences, 385 Serra Mall, Stanford University, Stanford, California 94305-5020, USA.
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Goodman CD. Physicians' unions must be able to strike. West J Med 1999; 171:297-8. [PMID: 10639861 PMCID: PMC1308735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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Alfenito MR, Souer E, Goodman CD, Buell R, Mol J, Koes R, Walbot V. Functional complementation of anthocyanin sequestration in the vacuole by widely divergent glutathione S-transferases. Plant Cell 1998; 10:1135-49. [PMID: 9668133 PMCID: PMC144053 DOI: 10.1105/tpc.10.7.1135] [Citation(s) in RCA: 246] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Glutathione S-transferases (GSTs) traditionally have been studied in plants and other organisms for their ability to detoxify chemically diverse herbicides and other toxic organic compounds. Anthocyanins are among the few endogenous substrates of plant GSTs that have been identified. The Bronze2 (Bz2) gene encodes a type III GST and performs the last genetically defined step of the maize anthocyanin pigment pathway. This step is the conjugation of glutathione to cyanidin 3-glucoside (C3G). Glutathionated C3G is transported to the vacuole via a tonoplast Mg-ATP-requiring glutathione pump (GS-X pump). Genetically, the comparable step in the petunia anthocyanin pathway is controlled by the Anthocyanin9 (An9) gene. An9 was cloned by transposon tagging and found to encode a type I plant GST. Bz2 and An9 have evolved independently from distinct types of GSTs, but each is regulated by the conserved transcriptional activators of the anthocyanin pathway. Here, a phylogenetic analysis is presented, with special consideration given to the origin of these genes and their relaxed substrate requirements. In particle bombardment tests, An9 and Bz2 functionally complement both mutants. Among several other GSTs tested, only soybean GmGST26A (previously called GmHsp26A and GH2/4) and maize GSTIII were found to confer vacuolar sequestration of anthocyanin. Previously, these genes had not been associated with the anthocyanin pathway. Requirements for An9 and Bz2 gene function were investigated by sequencing functional and nonfunctional germinal revertants of an9-T3529, bz2::Ds, and bz2::Mu1.
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Affiliation(s)
- M R Alfenito
- Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA
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Abstract
A Class 2 alpha-mannosidase gene was cloned and sequenced from the filamentous fungus Aspergillus nidulans. A portion of the gene was amplified using degenerate oligonucleotide primers which were designed based on similarity between the Saccharomyces cerevisiae vacuolar and rat ER/cytosolic Class 2 protein sequences. The PCR amplification product was used to isolate the full length gene, and DNA sequencing revealed a 3383 bp coding region containing three introns. The predicted 1049 amino acid reading frame contained six potential N-glycosylation sites and encoded a protein of 118 kDa. The protein sequence did not appear to encode a typical fungal signal sequence or membrane spanning domain. Although the cellular location of the A.nidulans mannosidase was not determined, experimental evidence suggested that it was located within a subcellular organelle. The Matchbox sequence similarity matrix indicated that the A.nidulans protein sequence was more highly similar to the rat ER/cytosolic (Rij = 0.33) and S.cerevisiae vacuolar alpha-mannosidases (Rij = 0.43) than the rat and yeast sequences were to each other (Rij = 0.29). These three enzymes were found to be distantly related to other Class 2 sequences, and compose a third subgroup of Class 2 alpha-mannosidases, as shown by ClustalW sequence alignment.
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Affiliation(s)
- C J Eades
- Department of Biology, University of Victoria, P.O. Box 3020, Victoria, British Columbia V8W 3N5, Canada
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Prout DL, DeLucia S, Cooper D, Luther B, Sugarbaker E, Taddeucci TN, Rybarcyk LJ, Rapaport J, Park BK, Goodman CD, Edwards G, Glashausser C, Sams T, Udagawa T, Osterfeld F. Spin decomposition of the Delta resonance cross section using the 12C(p. Phys Rev Lett 1996; 76:4488-4491. [PMID: 10061304 DOI: 10.1103/physrevlett.76.4488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Yang X, Wang L, Rapaport J, Goodman CD, Foster CC, Wang Y, Sugarbaker E, Marchlenski D, Luther B, Rybarcyk L, Taddeucci TN, Park BK. Dipole excitations in p-shell nuclei via (p,n) reactions. Phys Rev C Nucl Phys 1995; 52:2535-2545. [PMID: 9970784 DOI: 10.1103/physrevc.52.2535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Prout DL, Zafiratos C, Taddeucci TN, Ullmann J, Byrd RC, Carey TA, Lisowski P, McClelland JB, Rybarcyk LJ, Sailor W, Amian W, Braunstein M, Lind D, Mercer DJ, Cooper D, DeLucia S, Luther B, Marchlenski DG, Sugarbaker E, Rapaport J, Park BK, Gülmez E, Whitten CA, Goodman CD, Huang W, Ciskowski D, Alford WP. Cross sections and analyzing powers for quasielastic scattering at 795 and 495 MeV using the (p. Phys Rev C Nucl Phys 1995; 52:228-242. [PMID: 9970502 DOI: 10.1103/physrevc.52.228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Sams T, Ellegaard C, Gaarde C, Larsen JS, Boyard JL, Hennino T, Jourdain JC, Ramstein B, Roy-Stephan M, Radvanyi P, Brockstedt A, Österlund M, Zupranski P, Goodman CD, Ichimura M, Dmitriev VF. Quasifree (d. Phys Rev C Nucl Phys 1995; 51:1945-1960. [PMID: 9970263 DOI: 10.1103/physrevc.51.1945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Wang Y, Yang X, Rapaport J, Goodman CD, Luther BA, Marchlenski DG, Park BK, Rybarcyk L, Smith A, Sugarbaker E, Taddeucci T, Wang L. Study of the (1/2)g.s.--->(1/2)1+ transition in the 13C(p,n)13N reaction at intermediate energies. Phys Rev C Nucl Phys 1995; 51:1345-1347. [PMID: 9970185 DOI: 10.1103/physrevc.51.1345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Taddeucci TN, Luther BA, Rybarcyk LJ, Byrd RC, McClelland JB, Prout DL, DeLucia S, Cooper DA, Marchlenski DG, Sugarbaker E, Park BK, Sams T, Goodman CD, Rapaport J, Ichimura M, Kawahigashi K. Momentum Dependence of the Nuclear Isovector Spin Responses from (p. Phys Rev Lett 1994; 73:3516-3519. [PMID: 10057403 DOI: 10.1103/physrevlett.73.3516] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Wang L, Yang X, Rapaport J, Goodman CD, Foster CC, Wang Y, Piekarewicz J, Sugarbaker E, Marchlenski D, Luther B, Rybarcyk L, Taddeucci TN, Park BK. (p,n) quasifree excitations in p-shell nuclei at 186 MeV. Phys Rev C Nucl Phys 1994; 50:2438-2448. [PMID: 9969932 DOI: 10.1103/physrevc.50.2438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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