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Kangasjarvi E, Forsey J, Simpson JS, Ng SL. "We're back in control of the story and we're not letting anyone take that away from us": patient teacher programs as means for patient emancipation. Adv Health Sci Educ Theory Pract 2023:10.1007/s10459-023-10255-6. [PMID: 37455294 DOI: 10.1007/s10459-023-10255-6] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/04/2023] [Indexed: 07/18/2023]
Abstract
While patient engagement in healthcare professions education (HPE) has significantly increased in the past decades, a theoretical gap remains. What are the varied reasons as to why patients get involved with HPE programs? With a focus on understanding what drives patient involvement with HPE programs, this study examined how a patient as teacher (PAT) program was experienced by medical students, patient teachers, and faculty within a medical school. Through a phenomenographic approach, this study captures and describes the different ways our study participants experienced a PAT program (the 'phenomenon'). 24 semi-structured interviews were conducted in total, comprised of interviews with patient teachers (N = 10), medical students (N = 10) and program facilitators (N = 4) who participated in a PAT program. Our focus was on participants' description of the program and was grounded in their experiences of as well as their beliefs about it. Our findings captured 4 layers representing the qualitatively different (yet interrelated) ways in which participants experienced/perceived and conceptualized the various aspects of their experience with the PAT program: (1) A productive disruption of the learning space (2) A re-humanization within healthcare (3) A means of empowerment and agency (4) A catalyst for change and emancipation. Our outcome space results can be visually illustrated by a nesting "Matryoshka" doll, representing the four layers and depicting the process of uncovering the less conscious layers of sense-making within this phenomenon. HPE programs that are co-produced with patients and actively involve patients as teachers have the potential, but not guarantee, to be emancipatory. To engage in PAT programs that exhibit an emancipatory potential, we need to consider transformative paradigms of education, which are aligned with social change, and disrupt the traditional teacher-learner hierarchy.
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Affiliation(s)
- E Kangasjarvi
- Li Ka Shing Knowledge Institute, Applied Education Research Operatives (AERO), Faculty of Medicine, University of Toronto at St. Michael's Hospital, Unity Health Toronto, 30 Bond Street, Toronto, ON, M5B1W8, Canada.
| | - J Forsey
- University of Toronto, Rehabilitation Sciences Institute, Toronto, ON, Canada
| | - J S Simpson
- Division of General Surgery, St. Michael's Hospital, Unity Health Toronto, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - S L Ng
- University of Toronto, Centre for Interprofessional Education, University Health Network Toronto, Toronto, ON, Canada
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Han S, Quach T, Hu L, Lim SF, Zheng D, Leong NJ, Sharma G, Bonner D, Simpson JS, Trevaskis NL, Porter CJH. Increasing Linker Chain Length and Intestinal Stability Enhances Lymphatic Transport and Lymph Node Exposure of Triglyceride Mimetic Prodrugs of a Model Immunomodulator Mycophenolic Acid. Mol Pharm 2023; 20:2675-2685. [PMID: 36996486 DOI: 10.1021/acs.molpharmaceut.3c00099] [Citation(s) in RCA: 1] [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] [Indexed: 04/01/2023]
Abstract
Targeted delivery of immunomodulators to the lymphatic system has the potential to enhance therapeutic efficacy by increasing colocalization of drugs with immune targets such as lymphocytes. A triglyceride (TG)-mimetic prodrug strategy has been recently shown to enhance the lymphatic delivery of a model immunomodulator, mycophenolic acid (MPA), via incorporation into the intestinal TG deacylation-reacylation and lymph lipoprotein transport pathways. In the current study, a series of structurally related TG prodrugs of MPA were examined to optimize structure-lymphatic transport relationships for lymph-directing lipid-mimetic prodrugs. MPA was conjugated to the sn-2 position of the glyceride backbone of the prodrugs using linkers of different chain length (5-21 carbons) and the effect of methyl substitutions at the alpha and/or beta carbons to the glyceride end of the linker was examined. Lymphatic transport was assessed in mesenteric lymph duct cannulated rats, and drug exposure in lymph nodes was examined following oral administration to mice. Prodrug stability in simulated intestinal digestive fluid was also evaluated. Prodrugs with straight chain linkers were relatively unstable in simulated intestinal fluid; however, co-administration of lipase inhibitors (JZL184 and orlistat) was able to reduce instability and increase lymphatic transport (2-fold for a prodrug with a 6-carbon spacer, i.e., MPA-C6-TG). Methyl substitutions to the chain resulted in similar trends in improving intestinal stability and lymphatic transport. Medium- to long-chain spacers (C12, C15) between MPA and the glyceride backbone were most effective in promoting lymphatic transport, consistent with increases in lipophilicity. In contrast, short-chain (C6-C10) linkers appeared to be too unstable in the intestine and insufficiently lipophilic to associate with lymph lipid transport pathways, while very long-chain (C18, C21) linkers were also not preferred, likely as a result of increases in molecular weight reducing solubility or permeability. In addition to more effectively promoting drug transport into mesenteric lymph, TG-mimetic prodrugs based on a C12 linker resulted in marked increases (>40 fold) in the exposure of MPA in the mesenteric lymph nodes in mice when compared to administration of MPA alone, suggesting that optimizing prodrug design has the potential to provide benefit in targeting and modulating immune cells.
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Affiliation(s)
| | - Tim Quach
- PureTech Health, 6 Tide Street, Boston, Massachusetts 02210, United States
| | | | | | | | | | | | - Daniel Bonner
- PureTech Health, 6 Tide Street, Boston, Massachusetts 02210, United States
| | - Jamie S Simpson
- PureTech Health, 6 Tide Street, Boston, Massachusetts 02210, United States
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Quach T, Hu L, Han S, Lim SF, Senyschyn D, Yadav P, Trevaskis NL, Simpson JS, Porter CJH. Corrigendum: Triglyceride-mimetic prodrugs of buprenorphine enhance oral bioavailability via promotion of lymphatic transport. Front Pharmacol 2022; 13:1014363. [PMID: 36133812 PMCID: PMC9484298 DOI: 10.3389/fphar.2022.1014363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 08/09/2022] [Indexed: 12/03/2022] Open
Affiliation(s)
- Tim Quach
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Luojuan Hu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Sifei Han
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- *Correspondence: Sifei Han, ; Christopher J. H. Porter,
| | - Shea F. Lim
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Danielle Senyschyn
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Preeti Yadav
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Natalie L. Trevaskis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Jamie S. Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Christopher J. H. Porter
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- *Correspondence: Sifei Han, ; Christopher J. H. Porter,
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Eise NT, Simpson JS, Thompson PE, Ventura S. Aqueous extracts of Urtica dioica (stinging nettle) leaf contain a P2-purinoceptor antagonist—Implications for male fertility. PLoS One 2022; 17:e0271735. [PMID: 35900970 PMCID: PMC9333203 DOI: 10.1371/journal.pone.0271735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/06/2022] [Indexed: 11/18/2022] Open
Abstract
Stinging nettle root and leaf extracts were tested for their effect on prostatic smooth muscle contractility. Root extract did not affect electrical field stimulation induced-nerve mediated contractions of isolated rat prostates. On the other hand, leaf extract attenuated electrical field stimulation-induced contractions at all frequencies. Similarly, contractions elicited by exogenous administration of ATP and αβ-methylene ATP were inhibited by leaf extract, whereas contractions elicited by exogenous administration of noradrenaline or acetylcholine were unaffected. The active component was present within the aqueous phase of the leaf extract. In mouse mating studies, stinging nettle leaf extract (50 mg p.o. daily) reduced male fertility by 53% compared to vehicle-treated male mice. Cardiovascular parameters were unaffected by administration of stinging nettle leaf extract (p ≥ 0.057). Treated mice exhibited normal mating behaviour. Bladder and testes weighed less in stinging nettle leaf extract treated mice. All other organs and total body weight were unaffected. It is concluded that stinging nettle leaf extract reduces contractility of genitourinary smooth muscle by acting as an antagonist at postjunctional P2X1-purinoceptors. These data indicates that blocking sperm transport through pharmacological blockade of P2X1-purinoceptors via oral administration is consistent with an effective and convenient biological strategy male contraception.
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Affiliation(s)
- Nicole T. Eise
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Jamie S. Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Philip E. Thompson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Sabatino Ventura
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- * E-mail:
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Quach T, Hu L, Han S, Lim SF, Senyschyn D, Yadav P, Trevaskis NL, Simpson JS, Porter CJH. Triglyceride-Mimetic Prodrugs of Buprenorphine Enhance Oral Bioavailability via Promotion of Lymphatic Transport. Front Pharmacol 2022; 13:879660. [PMID: 35496278 PMCID: PMC9039622 DOI: 10.3389/fphar.2022.879660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 03/15/2022] [Indexed: 11/24/2022] Open
Abstract
Buprenorphine (BUP) is a potent opioid analgesic that is widely used for severe pain management and opioid replacement therapy. The oral bioavailability of BUP, however, is significantly limited by first-pass metabolism. Previous studies have shown that triglyceride (TG) mimetic prodrugs of the steroid hormone testosterone circumvent first-pass metabolism by directing drug transport through the intestinal lymphatics, bypassing the liver. The current study expanded this prodrug strategy to BUP. Here different self-immolative (SI) linkers were evaluated to conjugate BUP to the 2 position of the TG backbone via the phenol group on BUP. The SI linkers were designed to promote drug release in plasma. Lipolysis of the prodrug in the intestinal tract was examined via incubation with simulated intestinal fluid (SIF), and potential for parent drug liberation in the systemic circulation was evaluated via incubation in rat plasma. Lymphatic transport and bioavailability studies were subsequently conducted in mesenteric lymph duct or carotid artery-cannulated rats, respectively. TG prodrug derivatives were efficiently transported into the lymphatics (up to 45% of the dose in anaesthetised rats, vs. less than 0.1% for BUP). Incorporation of the SI linkers facilitated BUP release from the prodrugs in the plasma and in concert with high lymphatic transport led to a marked enhancement in oral bioavailability (up to 22-fold) compared to BUP alone. These data suggest the potential to develop an orally bioavailable BUP product which may have advantages with respect to patient preference when compared to current sublingual, transdermal patch or parenteral formulations.
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Affiliation(s)
- Tim Quach
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Luojuan Hu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Sifei Han
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- *Correspondence: Sifei Han, ; Christopher J. H. Porter,
| | - Shea F. Lim
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Danielle Senyschyn
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Preeti Yadav
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Natalie L. Trevaskis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Jamie S. Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Christopher J. H. Porter
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- *Correspondence: Sifei Han, ; Christopher J. H. Porter,
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Cao E, Watt MJ, Nowell CJ, Quach T, Simpson JS, De Melo Ferreira V, Agarwal S, Chu H, Srivastava A, Anderson D, Gracia G, Lam A, Segal G, Hong J, Hu L, Phang KL, Escott ABJ, Windsor JA, Phillips ARJ, Creek DJ, Harvey NL, Porter CJH, Trevaskis NL. Mesenteric lymphatic dysfunction promotes insulin resistance and represents a potential treatment target in obesity. Nat Metab 2021; 3:1175-1188. [PMID: 34545251 DOI: 10.1038/s42255-021-00457-w] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 08/13/2021] [Indexed: 02/08/2023]
Abstract
Visceral adipose tissue (VAT) encases mesenteric lymphatic vessels and lymph nodes through which lymph is transported from the intestine and mesentery. Whether mesenteric lymphatics contribute to adipose tissue inflammation and metabolism and insulin resistance is unclear. Here we show that obesity is associated with profound and progressive dysfunction of the mesenteric lymphatic system in mice and humans. We find that lymph from mice and humans consuming a high-fat diet (HFD) stimulates lymphatic vessel growth, leading to the formation of highly branched mesenteric lymphatic vessels that 'leak' HFD-lymph into VAT and, thereby, promote insulin resistance. Mesenteric lymphatic dysfunction is regulated by cyclooxygenase (COX)-2 and vascular endothelial growth factor (VEGF)-C-VEGF receptor (R)3 signalling. Lymph-targeted inhibition of COX-2 using a glyceride prodrug approach reverses mesenteric lymphatic dysfunction, visceral obesity and inflammation and restores glycaemic control in mice. Targeting obesity-associated mesenteric lymphatic dysfunction thus represents a potential therapeutic option to treat metabolic disease.
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Affiliation(s)
- Enyuan Cao
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.
| | - Matthew J Watt
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Cameron J Nowell
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Tim Quach
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Jamie S Simpson
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
- Puretech Health, Boston, MA, USA
| | - Vilena De Melo Ferreira
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Sonya Agarwal
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Hannah Chu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Anubhav Srivastava
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Dovile Anderson
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Gracia Gracia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Alina Lam
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Gabriela Segal
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- Biological Optical Microscopy Platform, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Jiwon Hong
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Surgical and Translational Research Centre, University of Auckland, Auckland, New Zealand
| | - Luojuan Hu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Kian Liun Phang
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Surgical and Translational Research Centre, University of Auckland, Auckland, New Zealand
| | - Alistair B J Escott
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Surgical and Translational Research Centre, University of Auckland, Auckland, New Zealand
| | - John A Windsor
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Surgical and Translational Research Centre, University of Auckland, Auckland, New Zealand
- HBP/Upper GI Unit, Department of General Surgery, Auckland City Hospital, Auckland, New Zealand
| | - Anthony R J Phillips
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Surgical and Translational Research Centre, University of Auckland, Auckland, New Zealand
| | - Darren J Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Natasha L Harvey
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Christopher J H Porter
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.
| | - Natalie L Trevaskis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia.
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Kochappan R, Cao E, Han S, Hu L, Quach T, Senyschyn D, Ferreira VI, Lee G, Leong N, Sharma G, Lim SF, Nowell CJ, Chen Z, von Andrian UH, Bonner D, Mintern JD, Simpson JS, Trevaskis NL, Porter CJH. Targeted delivery of mycophenolic acid to the mesenteric lymph node using a triglyceride mimetic prodrug approach enhances gut-specific immunomodulation in mice. J Control Release 2021; 332:636-651. [PMID: 33609620 DOI: 10.1016/j.jconrel.2021.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [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: 09/21/2020] [Revised: 02/07/2021] [Accepted: 02/08/2021] [Indexed: 12/22/2022]
Abstract
The mesenteric lymph nodes (MLN) are a key site for the generation of adaptive immune responses to gut-derived antigenic material and immune cells within the MLN contribute to the pathophysiology of a range of conditions including inflammatory and autoimmune diseases, viral infections, graft versus host disease and cancer. Targeting immunomodulating drugs to the MLN may thus be beneficial in a range of conditions. This paper investigates the potential benefit of targeting a model immunosuppressant drug, mycophenolic acid (MPA), to T cells in the MLN, using a triglyceride (TG) mimetic prodrug approach. We confirmed that administration of MPA in the TG prodrug form (MPA-TG), increased lymphatic transport of MPA-related species 83-fold and increased MLN concentrations of MPA >20 fold, when compared to MPA alone, for up to 4 h in mice. At the same time, the plasma exposure of MPA and MPA-TG was similar, limiting the opportunity for systemic side effects. Confocal microscopy and flow cytometry studies with a fluorescent model prodrug (Bodipy-TG) revealed that the prodrug accumulated in the MLN cortex and paracortex at 5 and 10 h following administration and was highly associated with B cells and T cells that are found in these regions of the MLN. Finally, we demonstrated that MPA-TG was significantly more effective than MPA at inhibiting CD4+ and CD8+ T cell proliferation in the MLN of mice in response to an oral ovalbumin antigen challenge. In contrast, MPA-TG was no more effective than MPA at inhibiting T cell proliferation in peripheral LN when mice were challenged via SC administration of ovalbumin. This paper provides the first evidence of an in vivo pharmacodynamic benefit of targeting the MLN using a TG mimetic prodrug approach. The TG mimetic prodrug technology has the potential to benefit the treatment of a range of conditions where aberrant immune responses are initiated in gut-associated lymphoid tissues.
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Affiliation(s)
- Ruby Kochappan
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Enyuan Cao
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Sifei Han
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia.
| | - Luojuan Hu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Tim Quach
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Danielle Senyschyn
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Vilena Ivanova Ferreira
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Given Lee
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Nathania Leong
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Garima Sharma
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Shea Fern Lim
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Cameron J Nowell
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Ziqi Chen
- Dept. of Immunology, Harvard Medical School and Ragon Institute of MGH, MIT and Harvard, 77 Ave. Louis Pasteur, Boston, MA 02115, USA
| | - Ulrich H von Andrian
- Dept. of Immunology, Harvard Medical School and Ragon Institute of MGH, MIT and Harvard, 77 Ave. Louis Pasteur, Boston, MA 02115, USA
| | - Daniel Bonner
- PureTech Health, 6 Tide Street, Boston, MA 02210, USA
| | - Justine D Mintern
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Bio21 Molecular Science and Biotechnology Institute, Parkville, Victoria 3010, Australia
| | - Jamie S Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; PureTech Health, 6 Tide Street, Boston, MA 02210, USA
| | - Natalie L Trevaskis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia.
| | - Christopher J H Porter
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia.
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8
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Han S, Quach T, Hu L, Lim SF, Gracia G, Trevaskis NL, Simpson JS, Porter CJH. The Impact of Conjugation Position and Linker Chemistry on the Lymphatic Transport of a Series of Glyceride and Phospholipid Mimetic Prodrugs. J Pharm Sci 2020; 110:489-499. [PMID: 33069711 DOI: 10.1016/j.xphs.2020.10.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 06/21/2020] [Revised: 10/07/2020] [Accepted: 10/07/2020] [Indexed: 10/23/2022]
Abstract
Drug delivery to the lymphatic system is gaining increasing attention, particularly in fields such as immunotherapy where drug access to lymphocytes is central to activity. We have previously described a prodrug strategy that facilitates the lymphatic delivery of a model immunomodulator, mycophenolic acid (MPA) via incorporation into intestinal triglyceride transport pathways. The current study explored a series of structurally related glyceride and phospholipid mimetic prodrugs of MPA in an attempt to enhance lymph targeting and to better elucidate the design criteria for lipid mimetic prodrugs. MPA was conjugated to a glyceride or phospholipid backbone at various positions using different spacers employing ester, ether, carbonate and amide bonds. Patterns of prodrug hydrolysis were evaluated in rat digestive fluid, and lymphatic transport and plasma pharmacokinetics were assessed in lymph duct cannulated rats. Prodrugs with different spacers between MPA and the glyceride backbone resulted in up to 70-fold differences in gastrointestinal stability. MPA conjugation at the 2 position of the glyceride backbone and via an ester bond were most effective in promoting lymphatic transport. Phospholipid prodrug derivatives, or glyceride derivatives with MPA attached at the 1 position or when linked via ether, carbonate or amide bonds were poorly incorporated into lymphatic transport pathways.
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Affiliation(s)
- Sifei Han
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Tim Quach
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Luojuan Hu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Shea Fern Lim
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Gracia Gracia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Natalie L Trevaskis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Jamie S Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Christopher J H Porter
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia.
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9
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Jensen DD, Lieu T, Halls ML, Veldhuis NA, Imlach WL, Mai QN, Poole DP, Quach T, Aurelio L, Conner J, Herenbrink CK, Barlow N, Simpson JS, Scanlon MJ, Graham B, McCluskey A, Robinson PJ, Escriou V, Nassini R, Materazzi S, Geppetti P, Hicks GA, Christie MJ, Porter CJH, Canals M, Bunnett NW. Neurokinin 1 receptor signaling in endosomes mediates sustained nociception and is a viable therapeutic target for prolonged pain relief. Sci Transl Med 2018; 9:9/392/eaal3447. [PMID: 28566424 DOI: 10.1126/scitranslmed.aal3447] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 03/17/2017] [Indexed: 12/25/2022]
Abstract
Typically considered to be cell surface sensors of extracellular signals, heterotrimeric GTP-binding protein (G protein)-coupled receptors (GPCRs) control many pathophysiological processes and are the target of 30% of therapeutic drugs. Activated receptors redistribute to endosomes, but researchers have yet to explore whether endosomal receptors generate signals that control complex processes in vivo and are viable therapeutic targets. We report that the substance P (SP) neurokinin 1 receptor (NK1R) signals from endosomes to induce sustained excitation of spinal neurons and pain transmission and that specific antagonism of the NK1R in endosomes with membrane-anchored drug conjugates provides more effective and sustained pain relief than conventional plasma membrane-targeted antagonists. Pharmacological and genetic disruption of clathrin, dynamin, and β-arrestin blocked SP-induced NK1R endocytosis and prevented SP-stimulated activation of cytosolic protein kinase C and nuclear extracellular signal-regulated kinase, as well as transcription. Endocytosis inhibitors prevented sustained SP-induced excitation of neurons in spinal cord slices in vitro and attenuated nociception in vivo. When conjugated to cholestanol to promote endosomal targeting, NK1R antagonists selectively inhibited endosomal signaling and sustained neuronal excitation. Cholestanol conjugation amplified and prolonged the antinociceptive actions of NK1R antagonists. These results reveal a critical role for endosomal signaling of the NK1R in the complex pathophysiology of pain and demonstrate the use of endosomally targeted GPCR antagonists.
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Affiliation(s)
- Dane D Jensen
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - TinaMarie Lieu
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Michelle L Halls
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Nicholas A Veldhuis
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Wendy L Imlach
- Discipline of Pharmacology, University of Sydney, New South Wales 2006, Australia
| | - Quynh N Mai
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Daniel P Poole
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Tim Quach
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Luigi Aurelio
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Joshua Conner
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Carmen Klein Herenbrink
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Nicholas Barlow
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Jamie S Simpson
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Martin J Scanlon
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Bimbil Graham
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Adam McCluskey
- School of Environmental and Life Sciences, University of Newcastle, New South Wales 2308, Australia
| | - Phillip J Robinson
- Children's Medical Research Institute, University of Sydney, New South Wales 2145, Australia
| | - Virginie Escriou
- Unité de Technologies Chimiques et Biologiques pour la Sante, CNRS UMR8258, INSERM U1022, Université Paris Descartes, Chimie ParisTech, 75006 Paris, France
| | - Romina Nassini
- Department of Health Sciences, Clinical Pharmacology Unit, University of Florence, 6-50139 Florence, Italy
| | - Serena Materazzi
- Department of Health Sciences, Clinical Pharmacology Unit, University of Florence, 6-50139 Florence, Italy
| | - Pierangelo Geppetti
- Department of Health Sciences, Clinical Pharmacology Unit, University of Florence, 6-50139 Florence, Italy
| | | | - Macdonald J Christie
- Discipline of Pharmacology, University of Sydney, New South Wales 2006, Australia
| | - Christopher J H Porter
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. .,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Meritxell Canals
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. .,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Nigel W Bunnett
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia. .,Australia Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia.,Department of Pharmacology and Therapeutics, University of Melbourne, Victoria 3010, Australia.,Departments of Surgery and Pharmacology, Columbia University College of Physicians and Surgeons, Columbia University, 21 Audubon Avenue, Room 209, New York City, NY 10032, USA
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10
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Cole CC, Carnell SC, Jiwa KJ, Birch JB, Hester KH, Ward CW, Simpson JS, Soyza ADSD. S46 Neutrophil vascular endothelial growth factor (VEGF) as a driving force for angiogenesis in bronchiectasis? Thorax 2016. [DOI: 10.1136/thoraxjnl-2016-209333.52] [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: 11/04/2022]
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11
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Mohanty B, Williams ML, Doak BC, Vazirani M, Ilyichova O, Wang G, Bermel W, Simpson JS, Chalmers DK, King GF, Mobli M, Scanlon MJ. Determination of ligand binding modes in weak protein-ligand complexes using sparse NMR data. J Biomol NMR 2016; 66:195-208. [PMID: 27778134 DOI: 10.1007/s10858-016-0067-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 09/29/2016] [Indexed: 06/06/2023]
Abstract
We describe a general approach to determine the binding pose of small molecules in weakly bound protein-ligand complexes by deriving distance constraints between the ligand and methyl groups from all methyl-containing residues of the protein. We demonstrate that using a single sample, which can be prepared without the use of expensive precursors, it is possible to generate high-resolution data rapidly and obtain the resonance assignments of Ile, Leu, Val, Ala and Thr methyl groups using triple resonance scalar correlation data. The same sample may be used to obtain Met εCH3 assignments using NOESY-based methods, although the superior sensitivity of NOESY using [U-13C,15N]-labeled protein makes the use of this second sample more efficient. We describe a structural model for a weakly binding ligand bound to its target protein, DsbA, derived from intermolecular methyl-to-ligand nuclear Overhauser enhancements, and demonstrate that the ability to assign all methyl resonances in the spectrum is essential to derive an accurate model of the structure. Once the methyl assignments have been obtained, this approach provides a rapid means to generate structural models for weakly bound protein-ligand complexes. Such weak complexes are often found at the beginning of programs of fragment based drug design and can be challenging to characterize using X-ray crystallography.
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Affiliation(s)
- Biswaranjan Mohanty
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Martin L Williams
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Bradley C Doak
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Mansha Vazirani
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Olga Ilyichova
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Geqing Wang
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
- La Trobe Institute for Molecular Bioscience, La Trobe University, Bundoora, VIC, 3083, Australia
| | - Wolfgang Bermel
- Bruker Biospin GmbH, Silberstreifen, 76287, Rheinstetten, Germany
| | - Jamie S Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - David K Chalmers
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, St Lucia, QLD, 4072, Australia.
| | - Martin J Scanlon
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia.
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12
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Hu L, Quach T, Han S, Lim SF, Yadav P, Senyschyn D, Trevaskis NL, Simpson JS, Porter CJH. Frontispiz: Glyceride-Mimetic Prodrugs Incorporating Self-Immolative Spacers Promote Lymphatic Transport, Avoid First-Pass Metabolism, and Enhance Oral Bioavailability. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201684461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Luojuan Hu
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Tim Quach
- Medicinal Chemistry; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Sifei Han
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Shea F. Lim
- Medicinal Chemistry; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Preeti Yadav
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Danielle Senyschyn
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Natalie L. Trevaskis
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Jamie S. Simpson
- Medicinal Chemistry; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Christopher J. H. Porter
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
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13
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Hu L, Quach T, Han S, Lim SF, Yadav P, Senyschyn D, Trevaskis NL, Simpson JS, Porter CJH. Frontispiece: Glyceride-Mimetic Prodrugs Incorporating Self-Immolative Spacers Promote Lymphatic Transport, Avoid First-Pass Metabolism, and Enhance Oral Bioavailability. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/anie.201684461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Luojuan Hu
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Tim Quach
- Medicinal Chemistry; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Sifei Han
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Shea F. Lim
- Medicinal Chemistry; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Preeti Yadav
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Danielle Senyschyn
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Natalie L. Trevaskis
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Jamie S. Simpson
- Medicinal Chemistry; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
| | - Christopher J. H. Porter
- Drug Delivery, Disposition and Dynamics; Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology; Monash Institute of Pharmaceutical Sciences, Monash University; 381 Royal Parade Parkville Victoria 3052 Australia
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14
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Wang G, Drinkwater N, Drew DR, MacRaild CA, Chalmers DK, Mohanty B, Lim SS, Anders RF, Beeson JG, Thompson PE, McGowan S, Simpson JS, Norton RS, Scanlon MJ. Structure–Activity Studies of β-Hairpin Peptide Inhibitors of the Plasmodium falciparum AMA1–RON2 Interaction. J Mol Biol 2016; 428:3986-3998. [DOI: 10.1016/j.jmb.2016.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 06/25/2016] [Accepted: 07/04/2016] [Indexed: 12/01/2022]
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15
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Han S, Hu L, Gracia, Quach T, Simpson JS, Edwards GA, Trevaskis NL, Porter CJH. Lymphatic Transport and Lymphocyte Targeting of a Triglyceride Mimetic Prodrug Is Enhanced in a Large Animal Model: Studies in Greyhound Dogs. Mol Pharm 2016; 13:3351-3361. [DOI: 10.1021/acs.molpharmaceut.6b00195] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
| | | | | | | | | | - Glenn A. Edwards
- School
of Animal and Veterinary Sciences, Charles Sturt University, Boorooma
Street, Wagga Wagga, New
South Wales 2650, Australia
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16
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Hu L, Quach T, Han S, Lim SF, Yadav P, Senyschyn D, Trevaskis NL, Simpson JS, Porter CJH. Glyceride‐Mimetic Prodrugs Incorporating Self‐Immolative Spacers Promote Lymphatic Transport, Avoid First‐Pass Metabolism, and Enhance Oral Bioavailability. Angew Chem Int Ed Engl 2016; 55:13700-13705. [DOI: 10.1002/anie.201604207] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/25/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Luojuan Hu
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Tim Quach
- Medicinal Chemistry Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Sifei Han
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Shea F. Lim
- Medicinal Chemistry Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Preeti Yadav
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Danielle Senyschyn
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Natalie L. Trevaskis
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Jamie S. Simpson
- Medicinal Chemistry Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Christopher J. H. Porter
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
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17
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Hu L, Quach T, Han S, Lim SF, Yadav P, Senyschyn D, Trevaskis NL, Simpson JS, Porter CJH. Glyceride‐Mimetic Prodrugs Incorporating Self‐Immolative Spacers Promote Lymphatic Transport, Avoid First‐Pass Metabolism, and Enhance Oral Bioavailability. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201604207] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Luojuan Hu
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Tim Quach
- Medicinal Chemistry Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Sifei Han
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Shea F. Lim
- Medicinal Chemistry Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Preeti Yadav
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Danielle Senyschyn
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Natalie L. Trevaskis
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Jamie S. Simpson
- Medicinal Chemistry Monash University 381 Royal Parade Parkville Victoria 3052 Australia
| | - Christopher J. H. Porter
- Drug Delivery, Disposition and Dynamics Monash University 381 Royal Parade Parkville Victoria 3052 Australia
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade Parkville Victoria 3052 Australia
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18
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Ragaz J, Qian H, Shakeraneh S, Fox J, Wilson KS, Simpson JS, Yoon JY, Wong H. Abstract P1-07-10: Increasing population rates of in-situ breast cancer [DCIS] are associated with reduced breast cancer (BrCa) mortality. A case for screening mammography and "overdiagnosis" linked to outcome benefits. Cancer Res 2016. [DOI: 10.1158/1538-7445.sabcs15-p1-07-10] [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: 11/16/2022]
Abstract
Abstract
INTRODUCTION:
Following the first phase of this project [Ref 1], we correlate here the rates of DCIS with BrCaMOR, in two regions of Canada - British Columbia [BC] and Atlantic Provinces [Atl.P].
We previously reported higher compliance in screening mammography [ScreenMam] and therapeutic [TH*] guidelines [GUIDELINES] for both DCIS and invasive BrCa in BC compared with Atl.P [Ref. 2].
METHODS: Annual age-specific rates [cases / 100,000 population] of DCIS, and BrCaMOR between BC vs Atl.P, were obtained for 17 age groups of 5 years (years 0-4 to 85+) and averaged each 5-year period from 1975-1979 up to 2005-2009. To compare age distribution, DCIS rates and BrCaMOR between the two regions, we selected four birth cohorts, age 30-34, 35-39, 40-44 and 45-49 in 1975-1979. From those, we tabulated the DCIS incidence and BrCaMOR for each birth cohort when they reached ages 50-54 and 60-64. We assumed that the rates of DCIS reflect annual ScreenMam practices.
Data were obtained from the Public Health Agency of Canada based on the Canadian Cancer Registry database at Statistics Canada.
RESULTS [N/100,000 population]British ColumbiaAtlantic ProvincesAge / years DCISBrCaMORDCISBrCaMORAge 50 â– 54 1980-8413.152.24.056.41985-8921.246.68.056.11990â–9429.244.421.449.91995â–9945.543.830.050.1Age 60â – 64 1990-9428.072.123.186.21995-9949.361.935.276.62000-0449.365.845.669.42005â–0951.453.141.059.4
CONCLUSIONS:
1. Our study shows across all age cohorts higher rates of DCIS and lower BrCaMOR in BC compared to Atl.P - results consistent with higher ScreenMam rates in BC than Atl.P.
2. These data are compatible with the concept that a higher diagnostic rate for early lesions such as DCIS [i.e. frequently designated as "Overdiagnosis"] by ScreenMam, and subsequent earlier Guideline TH*, contributes to lower BrCaMOR.
*TH Guidelines: surgery, radiation, Tamoxifen for DCIS; and the same + chemotherapy for early invasive disease.
Citation Format: Ragaz J, Qian H, Shakeraneh S, Fox J, Wilson KS, Simpson JS, Yoon J-Y, Wong H. Increasing population rates of in-situ breast cancer [DCIS] are associated with reduced breast cancer (BrCa) mortality. A case for screening mammography and "overdiagnosis" linked to outcome benefits. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-10.
References:
1. J. Ragaz, H. Wong, H. Qian, J.Fox, K. Wilson, A. Coldman: Cancer Research, May 1, 2015 75; P3-07-28
2. J. Ragaz, H. Wong, H. Qian: Cancer Research Feb 2010; 69(24 Supplement):2063-2063.
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Affiliation(s)
- J Ragaz
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
| | - H Qian
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
| | - S Shakeraneh
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
| | - J Fox
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
| | - KS Wilson
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
| | - JS Simpson
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
| | - J-Y Yoon
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
| | - H Wong
- School of Population and Public Health [SPPH], University of British Columbia [BC], Vancouver, BC, Canada; Centre for Health Evaluation and Outcome Sciences, Providence Health Care Research Institute, St. Paul's Hospital, University of B.C., Vancouver, BC, Canada; BC Cancer Agency [BCCA], Victoria, BC, Canada; UBC Medical School, Vancouver, BC, Canada; St. Michael Hospital, University of Toronto, Toronto, ON, Canada
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19
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Han S, Hu L, Quach T, Simpson JS, Trevaskis NL, Porter CJH. Constitutive Triglyceride Turnover into the Mesenteric Lymph Is Unable to Support Efficient Lymphatic Transport of a Biomimetic Triglyceride Prodrug. J Pharm Sci 2016; 105:786-796. [PMID: 26540595 DOI: 10.1002/jps.24670] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 09/07/2015] [Accepted: 09/11/2015] [Indexed: 12/17/2022]
Abstract
The triglyceride (TG) mimetic prodrug (1,3-dipalmitoyl-2-mycophenoloyl glycerol, 2-MPA-TG) biochemically integrates into intestinal lipid transport and lipoprotein assembly pathways and thereby promotes the delivery of mycophenolic acid (MPA) into the lymphatic system. As lipoprotein (LP) formation occurs constitutively, even in the fasted state, the current study aimed to determine whether lymphatic transport of 2-MPA-TG was dependent on coadministered exogenous lipid. In vitro incubation of the prodrug with rat digestive fluid and in situ intestinal perfusion experiments revealed that hydrolysis and absorption of the prodrug were relatively unaffected by the quantity of lipid in formulations. In vivo studies in rats, however, showed that the lymphatic transport of TG and 2-MPA-TG was significantly higher following administration with higher quantities of lipid and that oleic acid (C18:1) was more effective in promoting prodrug transport than lipids with higher degrees of unsaturation. The recovery of 2-MPA-TG and TG in lymph correlated strongly (R(2) = 0.99) and more than 97% of the prodrug was associated with chylomicrons. Inhibition of LP assembly by Pluronic L81 simultaneously inhibited the lymphatic transport of 2-MPA-TG and TG. In conclusion, although the TG mimetic prodrug effectively incorporates into TG resynthetic pathways, lipid coadministration is still required to support efficient lymphatic transport.
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Affiliation(s)
- Sifei Han
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Luojuan Hu
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Tim Quach
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia; Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Jamie S Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Natalie L Trevaskis
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
| | - Christopher J H Porter
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
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20
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Devine SM, Mulcair MD, Debono CO, Leung EWW, Nissink JWM, Lim SS, Chandrashekaran IR, Vazirani M, Mohanty B, Simpson JS, Baell JB, Scammells PJ, Norton RS, Scanlon MJ. Promiscuous 2-aminothiazoles (PrATs): a frequent hitting scaffold. J Med Chem 2015; 58:1205-14. [PMID: 25559643 DOI: 10.1021/jm501402x] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have identified a class of molecules, known as 2-aminothiazoles (2-ATs), as frequent-hitting fragments in biophysical binding assays. This was exemplified by 4-phenylthiazol-2-amine being identified as a hit in 14/14 screens against a diverse range of protein targets, suggesting that this scaffold is a poor starting point for fragment-based drug discovery. This prompted us to analyze this scaffold in the context of an academic fragment library used for fragment-based drug discovery (FBDD) and two larger compound libraries used for high-throughput screening (HTS). This analysis revealed that such "promiscuous 2-aminothiazoles" (PrATs) behaved as frequent hitters under both FBDD and HTS settings, although the problem was more pronounced in the fragment-based studies. As 2-ATs are present in known drugs, they cannot necessarily be deemed undesirable, but the combination of their promiscuity and difficulties associated with optimizing them into a lead compound makes them, in our opinion, poor scaffolds for fragment libraries.
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Affiliation(s)
- Shane M Devine
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia
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21
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Adams LA, Sharma P, Mohanty B, Ilyichova OV, Mulcair MD, Williams ML, Gleeson EC, Totsika M, Doak BC, Caria S, Rimmer K, Horne J, Shouldice SR, Vazirani M, Headey SJ, Plumb BR, Martin JL, Heras B, Simpson JS, Scanlon MJ. Application of Fragment-Based Screening to the Design of Inhibitors ofEscherichia coliDsbA. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201410341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Adams LA, Sharma P, Mohanty B, Ilyichova OV, Mulcair MD, Williams ML, Gleeson EC, Totsika M, Doak BC, Caria S, Rimmer K, Horne J, Shouldice SR, Vazirani M, Headey SJ, Plumb BR, Martin JL, Heras B, Simpson JS, Scanlon MJ. Application of fragment-based screening to the design of inhibitors of Escherichia coli DsbA. Angew Chem Int Ed Engl 2014; 54:2179-84. [PMID: 25556635 DOI: 10.1002/anie.201410341] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/25/2014] [Indexed: 12/11/2022]
Abstract
The thiol-disulfide oxidoreductase enzyme DsbA catalyzes the formation of disulfide bonds in the periplasm of Gram-negative bacteria. DsbA substrates include proteins involved in bacterial virulence. In the absence of DsbA, many of these proteins do not fold correctly, which renders the bacteria avirulent. Thus DsbA is a critical mediator of virulence and inhibitors may act as antivirulence agents. Biophysical screening has been employed to identify fragments that bind to DsbA from Escherichia coli. Elaboration of one of these fragments produced compounds that inhibit DsbA activity in vitro. In cell-based assays, the compounds inhibit bacterial motility, but have no effect on growth in liquid culture, which is consistent with selective inhibition of DsbA. Crystal structures of inhibitors bound to DsbA indicate that they bind adjacent to the active site. Together, the data suggest that DsbA may be amenable to the development of novel antibacterial compounds that act by inhibiting bacterial virulence.
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Affiliation(s)
- Luke A Adams
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052 (Australia) http://www.pharm.monash.edu.au
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23
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Han S, Hu L, Quach T, Simpson JS, Trevaskis NL, Porter CJH. Profiling the Role of Deacylation-Reacylation in the Lymphatic Transport of a Triglyceride-Mimetic Prodrug. Pharm Res 2014; 32:1830-44. [DOI: 10.1007/s11095-014-1579-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/13/2014] [Indexed: 01/03/2023]
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24
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Vinh NB, Devine SM, Munoz L, Ryan RM, Wang BH, Krum H, Chalmers DK, Simpson JS, Scammells PJ. Design, Synthesis, and Biological Evaluation of Tetra-Substituted Thiophenes as Inhibitors of p38α MAPK. ChemistryOpen 2014; 4:56-64. [PMID: 25861571 PMCID: PMC4380954 DOI: 10.1002/open.201402076] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [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: 09/29/2014] [Indexed: 12/30/2022] Open
Abstract
p38α mitogen-activated protein kinase (MAPK) plays a role in several cellular processes and consequently has been a therapeutic target in inflammatory diseases, cancer, and cardiovascular disease. A number of known p38α MAPK inhibitors contain vicinal 4-fluorophenyl/4-pyridyl rings connected to either a 5- or 6-membered heterocycle. In this study, a small library of substituted thiophene-based compounds bearing the vicinal 4-fluorophenyl/4-pyridyl rings was designed using computational docking as a visualisation tool. Compounds were synthesised and evaluated in a fluorescence polarisation binding assay. The synthesised analogues had a higher binding affinity to the active phosphorylated form of p38α MAPK than the inactive nonphosphorylated form of the protein. 4-(2-(4-fluorophenyl)thiophen-3-yl)pyridine had a Ki value of 0.6 μm to active p38α MAPK highlighting that substitution of the core ring to a thiophene retains affinity to the enzyme and can be utilised in p38α MAPK inhibitors. This compound was further elaborated using a substituted phenyl ring in order to probe the second hydrophobic pocket. Many of these analogues exhibited low micromolar affinity to active p38α MAPK. The suppression of neonatal rat fibroblast collagen synthesis was also observed suggesting that further development of these compounds may lead to potential therapeutics having cardioprotective properties.
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Affiliation(s)
- Natalie B Vinh
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade, Parkville, VIC 3052 (Australia)
| | - Shane M Devine
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade, Parkville, VIC 3052 (Australia)
| | - Lenka Munoz
- Discipline of Pharmacology, School of Medical Sciences and Bosch Institute, The University of Sydney Sydney, NSW 2006 (Australia)
| | - Renae M Ryan
- Discipline of Pharmacology, School of Medical Sciences and Bosch Institute, The University of Sydney Sydney, NSW 2006 (Australia)
| | - Bing H Wang
- Centre of Cardiovascular Research and Education in Therapeutics, Department of Epidemiology and Preventative Medicine, Monash University 99 Commercial Road, Melbourne, VIC 3004 (Australia)
| | - Henry Krum
- Centre of Cardiovascular Research and Education in Therapeutics, Department of Epidemiology and Preventative Medicine, Monash University 99 Commercial Road, Melbourne, VIC 3004 (Australia)
| | - David K Chalmers
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade, Parkville, VIC 3052 (Australia)
| | - Jamie S Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade, Parkville, VIC 3052 (Australia)
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University 381 Royal Parade, Parkville, VIC 3052 (Australia)
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25
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Chin YKY, Headey S, Mohanty B, Emsley J, Simpson JS, Scanlon MJ. Assignments of human integrin α1I domain in the apo and Mg²⁺ bound states. Biomol NMR Assign 2014; 8:117-121. [PMID: 23339031 DOI: 10.1007/s12104-013-9465-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/12/2013] [Indexed: 06/01/2023]
Abstract
The α1β1 integrin receptor binds to its main extracellular ligand, collagen, through an inserted domain in its α-subunit called the αI domain (αI). αI contains a metal binding site that allows collagen to coordinate to the domain through a divalent metal ion. Here we report the backbone assignments of the apo and Mg(2+) bound state of the isolated human α1I and the chemical shift changes resulting from metal coordination.
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Affiliation(s)
- Yanni K-Y Chin
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC, 3052, Australia
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26
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Chua T, Eise NT, Simpson JS, Ventura S. Pharmacological characterization and chemical fractionation of a liposterolic extract of saw palmetto (Serenoa repens): effects on rat prostate contractility. J Ethnopharmacol 2014; 152:283-291. [PMID: 24463033 DOI: 10.1016/j.jep.2013.12.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 12/06/2013] [Accepted: 12/18/2013] [Indexed: 06/03/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Saw palmetto (Serenoa repens) was first used medicinally by native American Indians to treat urological disorders. Nowadays, saw palmetto extracts are widely used in Europe and North America to treat the urinary symptoms associated with benign prostatic hyperplasia even though its mechanisms of action are poorly understood. This study aimed to characterize the bioactive constituents of a lipid extract of saw palmetto that are able to affect contractility of the rat prostate gland. The mechanism of action will also be investigated. MATERIALS AND METHODS A commercially available lipid extract of saw palmetto was subjected to fractionation using normal phase column chromatography. Composition of fractions was assessed by proton nuclear magnetic resonance spectroscopy ((1)H NMR) and mass spectrometry (MS). Contractile activities of these fractions were evaluated pharmacologically using isolated preparations of rat prostate gland and compared to the activity of the crude extract. RESULTS Saw palmetto extract inhibited contractions of the rat prostate gland which were consistent with smooth muscle relaxant activity. Only the ethyl acetate fraction resulting from chromatography inhibited contractions of isolated rat prostates similarly to the inhibition produced by the crude lipid extract. Comparison with authentic samples and analysis of NMR data revealed that this bioactivity was due to the fatty acid components present in the ethyl acetate fraction. Bioassay using various pharmacological tools identified multiple contractile mechanisms which were affected by the bioactive constituents. CONCLUSION A fatty acid component of saw palmetto extract causes inhibition of prostatic smooth muscle contractions via a non-specific mechanism.
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Affiliation(s)
- Thiam Chua
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Nicole T Eise
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Jamie S Simpson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Sabatino Ventura
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia.
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27
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Chin YKY, Headey SJ, Mohanty B, Patil R, McEwan PA, Swarbrick JD, Mulhern TD, Emsley J, Simpson JS, Scanlon MJ. The structure of integrin α1I domain in complex with a collagen-mimetic peptide. J Biol Chem 2013; 288:36796-809. [PMID: 24187131 PMCID: PMC3873540 DOI: 10.1074/jbc.m113.480251] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 10/04/2013] [Indexed: 11/06/2022] Open
Abstract
We have determined the structure of the human integrin α1I domain bound to a triple-helical collagen peptide. The structure of the α1I-peptide complex was investigated using data from NMR, small angle x-ray scattering, and size exclusion chromatography that were used to generate and validate a model of the complex using the data-driven docking program, HADDOCK (High Ambiguity Driven Biomolecular Docking). The structure revealed that the α1I domain undergoes a major conformational change upon binding of the collagen peptide. This involves a large movement in the C-terminal helix of the αI domain that has been suggested to be the mechanism by which signals are propagated in the intact integrin receptor. The structure suggests a basis for the different binding selectivity observed for the α1I and α2I domains. Mutational data identify residues that contribute to the conformational change observed. Furthermore, small angle x-ray scattering data suggest that at low collagen peptide concentrations the complex exists in equilibrium between a 1:1 and 2:1 α1I-peptide complex.
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Affiliation(s)
- Yanni K.-Y. Chin
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Stephen J. Headey
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Biswaranjan Mohanty
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
- Australian Research Council Centre of Excellence for Coherent X-ray Science, Monash University, Parkville, Victoria 3052, Australia
| | - Rahul Patil
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Paul A. McEwan
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom, and
| | - James D. Swarbrick
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Terrence D. Mulhern
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Jonas Emsley
- School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom, and
| | - Jamie S. Simpson
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
| | - Martin J. Scanlon
- From Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences and
- Australian Research Council Centre of Excellence for Coherent X-ray Science, Monash University, Parkville, Victoria 3052, Australia
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28
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Chhabra S, Dolezal O, Hattarki M, Peat TS, Simpson JS, Swarbrick JD. Fragment Screening on Staphylococcus aureus HPPK – a Folate Pathway Target. Aust J Chem 2013. [DOI: 10.1071/ch13298] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An NMR-based screen of a commercially available fragment library was performed on the folate pathway antimicrobial target, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase from Staphylococcus aureus (SaHPPK). Initial 1D saturation transfer difference-NMR screening resulted in an impractically high hit rate (43 %), which advocated the use of a strategy based on 2D (SOFAST) 15N HMQC NMR experiments. Chemical shift perturbations were used to identify, validate, and map the location of 16 initial binders (hit rate of 2 %). Fourteen compounds were purchased based on an identified thioamide pharmacophore. Binding affinities (Kd) were measured by surface plasmon resonance, revealing a modest improvement in potency over the initial 16 hits, with the best fragment found to bind to the apo enzyme with a Kd of 420 µM, corresponding to a ligand efficiency of 1.8 kJ/heavy atom. Four fragments identified represent useful starting points for the generation of leads that may ultimately be developed into new antimicrobial agents.
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29
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Vom A, Headey S, Wang G, Capuano B, Yuriev E, Scanlon MJ, Simpson JS. Detection and Prevention of Aggregation-based False Positives in STD-NMR-based Fragment Screening. Aust J Chem 2013. [DOI: 10.1071/ch13286] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aggregation of small organic compounds is a problem encountered in a variety of assay screening formats where it often results in detection of false positives. A saturation transfer difference-NMR-detected screen of a commercially available fragment library, followed by biochemical assay, identified several inhibitors of the enzyme ketopantoate reductase. These inhibitors were subsequently revealed to be aggregation-based false positives. Modification of the fragment screen by addition of detergent in the saturation transfer difference-NMR experiments allowed an assay format to be developed that resulted in the identification of genuine hit molecules suitable for further development.
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30
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Abstract
The design of a suitable library is an essential prerequisite to establish a fragment-based screening capability. Several pharmaceutical companies have described their approaches to establishing fragment libraries; however there are few detailed reports of both design and analysis of performance for a fragment library maintained in an academic setting. Here we report our efforts towards the design of a fragment library for nuclear magnetic resonance spectroscopy-based screening, demonstrate the performance of the library through analysis of 14 screens, and present a comparison to previously reported fragment libraries.
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31
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Lim SS, Debono CO, MacRaild CA, Chandrashekaran IR, Dolezal O, Anders RF, Simpson JS, Scanlon MJ, Devine SM, Scammells PJ, Norton RS. Development of Inhibitors of Plasmodium falciparum Apical Membrane Antigen 1 Based on Fragment Screening. Aust J Chem 2013. [DOI: 10.1071/ch13266] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Apical membrane antigen 1 (AMA1) is an essential component of the moving junction complex used by Plasmodium falciparum to invade human red blood cells. AMA1 has a conserved hydrophobic cleft that is the site of key interactions with the rhoptry neck protein complex. Our goal is to develop small molecule inhibitors of AMA1 with broad strain specificity, which we are pursuing using a fragment-based approach. In our screening campaign, we identified fragments that bind to the hydrophobic cleft with a hit rate of 5 %. The high hit rate observed strongly suggests that a druggable pocket is present within the cleft.
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32
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Vinh NB, Simpson JS, Scammells PJ, Chalmers DK. Virtual screening using a conformationally flexible target protein: models for ligand binding to p38α MAPK. J Comput Aided Mol Des 2012; 26:409-23. [PMID: 22527960 DOI: 10.1007/s10822-012-9569-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 03/26/2012] [Indexed: 12/25/2022]
Abstract
We have used virtual screening to develop models for the binding of aryl substituted heterocycles to p38α MAPK. Virtual screening was conducted on a number of p38α MAPK crystal structures using a library of 46 known p38α MAPK inhibitors containing a heterocyclic core substituted by pyridine and fluorophenyl rings (structurally related to SB203580) and a set of decoy compounds. Multiple protonation states and tautomers of active and decoy compounds were considered. Each docking model was evaluated using receiver operating characteristic (ROC) curves and enrichment factors. The two best performing single crystal structures were found to be 1BL7 and 2EWA, with enrichment factors of 14.1 and 13.0 at 2% of the virtual screen respectively. Ensembles of up to four receptors of similar conformations were generated, generally giving good or very good performances with high ROC AUCs and good enrichment. The 1BL7-2EWA ensemble was able to outperform each of its constituent receptors and gave high enrichment factors of 17.3, 12.0, 8.0 at 2, 5 and 10% respectively, of the virtual screen. A ROC AUC of 0.94 was obtained for this ensemble. This method may be applied to other proteins where there are a large number of inhibitor classes with different binding site conformations.
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Affiliation(s)
- Natalie B Vinh
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC, 3052, Australia
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33
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Chhabra S, Dolezal O, Collins BM, Newman J, Simpson JS, Macreadie IG, Fernley R, Peat TS, Swarbrick JD. Structure of S. aureus HPPK and the discovery of a new substrate site inhibitor. PLoS One 2012; 7:e29444. [PMID: 22276115 PMCID: PMC3261883 DOI: 10.1371/journal.pone.0029444] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [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: 09/06/2011] [Accepted: 11/28/2011] [Indexed: 12/17/2022] Open
Abstract
The first structural and biophysical data on the folate biosynthesis pathway enzyme and drug target, 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (SaHPPK), from the pathogen Staphylococcus aureus is presented. HPPK is the second essential enzyme in the pathway catalysing the pyrophosphoryl transfer from cofactor (ATP) to the substrate (6-hydroxymethyl-7,8-dihydropterin, HMDP). In-silico screening identified 8-mercaptoguanine which was shown to bind with an equilibrium dissociation constant, Kd, of ∼13 µM as measured by isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR). An IC50 of ∼41 µM was determined by means of a luminescent kinase assay. In contrast to the biological substrate, the inhibitor has no requirement for magnesium or the ATP cofactor for competitive binding to the substrate site. The 1.65 Å resolution crystal structure of the inhibited complex showed that it binds in the pterin site and shares many of the key intermolecular interactions of the substrate. Chemical shift and 15N heteronuclear NMR measurements reveal that the fast motion of the pterin-binding loop (L2) is partially dampened in the SaHPPK/HMDP/α,β-methylene adenosine 5′-triphosphate (AMPCPP) ternary complex, but the ATP loop (L3) remains mobile on the µs-ms timescale. In contrast, for the SaHPPK/8-mercaptoguanine/AMPCPP ternary complex, the loop L2 becomes rigid on the fast timescale and the L3 loop also becomes more ordered – an observation that correlates with the large entropic penalty associated with inhibitor binding as revealed by ITC. NMR data, including 15N-1H residual dipolar coupling measurements, indicate that the sulfur atom in the inhibitor is important for stabilizing and restricting important motions of the L2 and L3 catalytic loops in the inhibited ternary complex. This work describes a comprehensive analysis of a new HPPK inhibitor, and may provide a foundation for the development of novel antimicrobials targeting the folate biosynthetic pathway.
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Affiliation(s)
- Sandeep Chhabra
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Olan Dolezal
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Brett M. Collins
- Institute for Molecular Bioscience, The University of Queensland, Australia
| | - Janet Newman
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Jamie S. Simpson
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Ian G. Macreadie
- School of Applied Sciences, RMIT University, Bundoora, Australia
| | - Ross Fernley
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - Thomas S. Peat
- CSIRO Division of Materials, Science and Engineering, Parkville, Australia
| | - James D. Swarbrick
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
- * E-mail:
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Simpson JS, Ma G, Holloway CMB. Imaging technologies in breast diagnosis and surgical treatment. MINERVA CHIR 2011; 66:455-468. [PMID: 22117211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The diagnostic and surgical management of breast cancer has changed dramatically over the past 2 decades. All facets in the multidisciplinary management of breast cancer are rapidly evolving and being driven forward by technological advances. Conventional imaging techniques are now being augmented with advances in molecular imaging that probe biological properties of tissue to create images, and optical imaging which reflects physical properties of normal and diseased tissues. Automated computer assisted biopsy techniques are being developed to sample breast tissue with a higher degree of accuracy and patient comfort. As the trend toward minimally invasive breast surgery continues ablative techniques such as radiofrequency ablation, cryoablation, interstitial laser ablation and focused ultrasound ablation are being explored to potentially avoid the need for surgery all together. New intraoperative lesion localization techniques such as 3-dimensional ultrasonographic tumor models, magnetic resonance imaging (MRI)-guided projection and reproduction, radioguided occult lesion localization and optical imaging techniques are being developed to improve surgical guidance. Evaluation of advanced imaging and intraoperative guidance techniques requires more comprehensive histopathological examination of surgical specimens, prompting the development of techniques aimed at to improving upon the current limitations in breast pathology. This review will describe the development of new technologies in breast imaging, tumor ablation, intraoperative surgical guidance and tissue processing aimed at advancing minimally invasive diagnosis and treatment of breast cancer.
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Affiliation(s)
- J S Simpson
- Sunnybrook Health Sciences Center, Toronto, Canada
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Doak BC, Scanlon MJ, Simpson JS. Synthesis of Unsymmetrical 1,1′-Disubstituted Bis(1,2,3-triazole)s Using Monosilylbutadiynes. Org Lett 2011; 13:537-9. [DOI: 10.1021/ol102852z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
BACKGROUND To identify the bioactive components of saw palmetto ethanol extracts that affect contractility in the rat prostate gland. METHODS A commercially available saw palmetto ethanol extract was lyophilized then subjected to fractionation using silica gel column chromatography. Composition of fractions was assessed by proton nuclear magnetic resonance ((1)H NMR) spectroscopy and mass spectrometry (MS). Contractile activity of these fractions was evaluated pharmacologically using isolated preparations of rat prostate gland and compared to the activity of crude ethanol extract. RESULTS Saw palmetto ethanol extract caused contractions of the rat prostate gland which were consistent with indirectly acting sympathomimetic activity. Fractions resulting from chromatography produced contractions of isolated rat prostates that were similar in magnitude to the contractions produced by the crude extracts. Analysis of NMR and mass spectra revealed that this bioactivity was due to tyramine in the active fraction. CONCLUSIONS Tyramine is present in saw palmetto ethanol extracts and causes indirect α(1)-adrenoceptor mediated contractions via the release of noradrenaline from sympathetic neurons. This has clinical implications, as tyramine interacts with MAO inhibitors to cause hypertensive crisis.
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Affiliation(s)
- Thiam Chua
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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Brandli A, Simpson JS, Ventura S. Isoflavones isolated from red clover (Trifolium pratense) inhibit smooth muscle contraction of the isolated rat prostate gland. Phytomedicine 2010; 17:895-901. [PMID: 20638256 DOI: 10.1016/j.phymed.2010.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 02/23/2010] [Accepted: 05/25/2010] [Indexed: 05/29/2023]
Abstract
This study investigated whether red clover contains any bioactive constituents which may affect contractility of rat prostatic smooth muscle in an attempt to determine whether its medicinal use in the treatment of benign prostatic hyperplasia is supported by pharmacological effects. A commercially available red clover extract was chemically fractionated and various isoflavones (genistein, formononetin and biochanin A) were isolated from these fractions and their effects on contractility were examined on preparations of the isolated rat prostate gland. Contractile effects of the isolated fractions were compared with commercially available isoflavones (genistein, formononetin and biochanin A). Pharmacological tools were used to investigate the mechanism of action modifying smooth muscle contraction. Crude red clover extract (Trinovin) inhibited electrical field stimulation induced contractions of the rat prostate across a range of frequencies with an IC(50) of approximately 68 microg/ml. Contractions of the rat prostate elicited by exogenous administration of acetylcholine, noradrenaline or adenosine 5'-triphosphate (ATP) were also inhibited. Chromatographic separation, and final purification by high performance liquid chromatography (HPLC) permitted the isolation of the isoflavones: daidzein, calycosin, formononetin, prunetin, pratensin, biochanin A and genistein. Genistein, formononetin and biochanin A (100 microM) from either commercial sources or isolated from red clover extract inhibited electrical field stimulation induced contractions of the isolated rat prostate. It is concluded that isoflavones contained in red clover are able to inhibit prostatic smooth muscle contractions in addition to their antiproliferative effects. However, the high concentrations required to observe these smooth muscle relaxant effects mean that a therapeutic benefit from this mechanism is unlikely at doses used clinically.
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Affiliation(s)
- A Brandli
- Prostate Research Co-operative, Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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Chhabra S, Newman J, Peat TS, Fernley RT, Caine J, Simpson JS, Swarbrick JD. Crystallization and preliminary X-ray analysis of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase from Staphylococcus aureus. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:575-8. [PMID: 20445263 PMCID: PMC2864696 DOI: 10.1107/s1744309110010857] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 03/23/2010] [Indexed: 11/10/2022]
Abstract
6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) catalyzes the Mg(2+)-dependent transfer of pyrophosphate from ATP to 6-hydroxymethyl-7,8-dihydropterin (HMDP), forming 6-hydroxymethyl-7,8-dihydropterin pyrophosphate, which is a critical step in the de novo folic acid-biosynthesis pathway. Diffraction-quality crystals of HPPK from the medically relevant species Staphylococcus aureus were grown in the presence of ammonium sulfate or sodium malonate and diffracted to better than 1.65 A resolution. The crystals belonged to space group P2(1), with unit-cell parameters a = 36.8, b = 76.6, c = 51.5 A, alpha = gamma = 90.0, beta = 100.2 degrees . The crystals contained two molecules per asymmetric unit, with a volume per protein weight (V(M)) of 2.04 A(3) Da(-1) and an estimated solvent content of 39.6%.
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Affiliation(s)
- Sandeep Chhabra
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
- CSIRO Division of Molecular and Health Technologies, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Janet Newman
- CSIRO Division of Molecular and Health Technologies, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Thomas S. Peat
- CSIRO Division of Molecular and Health Technologies, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Ross T. Fernley
- CSIRO Division of Molecular and Health Technologies, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Joanne Caine
- CSIRO Division of Molecular and Health Technologies, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Jamie S. Simpson
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - James D. Swarbrick
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
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Vivian JP, Scoullar J, Rimmer K, Bushell SR, Beddoe T, Wilce MCJ, Byres E, Boyle TP, Doak B, Simpson JS, Graham B, Heras B, Kahler CM, Rossjohn J, Scanlon MJ. Structure and function of the oxidoreductase DsbA1 from Neisseria meningitidis. J Mol Biol 2009; 394:931-43. [PMID: 19815019 DOI: 10.1016/j.jmb.2009.09.065] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2009] [Revised: 09/25/2009] [Accepted: 09/30/2009] [Indexed: 10/20/2022]
Abstract
Neisseria meningitidis encodes three DsbA oxidoreductases (NmDsbA1-NmDsbA3) that are vital for the oxidative folding of many membrane and secreted proteins, and these three enzymes are considered to exhibit different substrate specificities. This has led to the suggestion that each N. meningitidis DsbA (NmDsbA) may play a specialized role in different stages of pathogenesis; however, the molecular and structural bases of the different roles of NmDsbAs are unclear. With the aim of determining the molecular basis for substrate specificity and how this correlates to pathogenesis, we undertook a biochemical and structural characterization of the three NmDsbAs. We report the 2.0-A-resolution crystal structure of the oxidized form of NmDsbA1, which adopted a canonical DsbA fold similar to that observed in the structures of NmDsbA3 and Escherichia coli DsbA (EcDsbA). Structural comparisons revealed variations around the active site and candidate peptide-binding region. Additionally, we demonstrate that all three NmDsbAs are strong oxidases with similar redox potentials; however, they differ from EcDsbA in their ability to be reoxidized by E. coli DsbB. Collectively, our studies suggest that the small structural differences between the NmDsbA enzymes and EcDsbA are functionally significant and are the likely determinants of substrate specificity.
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Affiliation(s)
- Julian P Vivian
- The Protein Crystallography Unit, Australian Research Council Center of Excellence in Structural and Functional Microbial Genomics, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
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Paxman JJ, Borg NA, Horne J, Thompson PE, Chin Y, Sharma P, Simpson JS, Wielens J, Piek S, Kahler CM, Sakellaris H, Pearce M, Bottomley SP, Rossjohn J, Scanlon MJ. The structure of the bacterial oxidoreductase enzyme DsbA in complex with a peptide reveals a basis for substrate specificity in the catalytic cycle of DsbA enzymes. J Biol Chem 2009; 284:17835-45. [PMID: 19389711 PMCID: PMC2719422 DOI: 10.1074/jbc.m109.011502] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 04/22/2009] [Indexed: 11/06/2022] Open
Abstract
Oxidative protein folding in Gram-negative bacteria results in the formation of disulfide bonds between pairs of cysteine residues. This is a multistep process in which the dithiol-disulfide oxidoreductase enzyme, DsbA, plays a central role. The structure of DsbA comprises an all helical domain of unknown function and a thioredoxin domain, where active site cysteines shuttle between an oxidized, substrate-bound, reduced form and a DsbB-bound form, where DsbB is a membrane protein that reoxidizes DsbA. Most DsbA enzymes interact with a wide variety of reduced substrates and show little specificity. However, a number of DsbA enzymes have now been identified that have narrow substrate repertoires and appear to interact specifically with a smaller number of substrates. The transient nature of the DsbA-substrate complex has hampered our understanding of the factors that govern the interaction of DsbA enzymes with their substrates. Here we report the crystal structure of a complex between Escherichia coli DsbA and a peptide with a sequence derived from a substrate. The binding site identified in the DsbA-peptide complex was distinct from that observed for DsbB in the DsbA-DsbB complex. The structure revealed details of the DsbA-peptide interaction and suggested a mechanism by which DsbA can simultaneously show broad specificity for substrates yet exhibit specificity for DsbB. This mode of binding was supported by solution nuclear magnetic resonance data as well as functional data, which demonstrated that the substrate specificity of DsbA could be modified via changes at the binding interface identified in the structure of the complex.
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Affiliation(s)
- Jason J. Paxman
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
| | - Natalie A. Borg
- the Protein Crystallography Unit, Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800
| | - James Horne
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
| | - Philip E. Thompson
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
| | - Yanni Chin
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
| | - Pooja Sharma
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
| | - Jamie S. Simpson
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
| | - Jerome Wielens
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
| | - Susannah Piek
- the School of Biomedical, Biomolecular and Chemical Sciences, QEII Medical Centre, University of Western Australia, Crawley, Western Australia 6009, and
| | - Charlene M. Kahler
- the School of Biomedical, Biomolecular and Chemical Sciences, QEII Medical Centre, University of Western Australia, Crawley, Western Australia 6009, and
| | - Harry Sakellaris
- the School of Biomedical, Biomolecular and Chemical Sciences, QEII Medical Centre, University of Western Australia, Crawley, Western Australia 6009, and
| | - Mary Pearce
- the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Stephen P. Bottomley
- the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Jamie Rossjohn
- the Protein Crystallography Unit, Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800
| | - Martin J. Scanlon
- From Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052
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Velkov T, Lim MLR, Horne J, Simpson JS, Porter CJH, Scanlon MJ. Characterization of lipophilic drug binding to rat intestinal fatty acid binding protein. Mol Cell Biochem 2009; 326:87-95. [PMID: 19160019 DOI: 10.1007/s11010-008-0009-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Accepted: 07/08/2008] [Indexed: 12/27/2022]
Abstract
Intestinal fatty acid binding protein (I-FABP) is present at high levels in the absorptive cells of the intestine (enterocytes) where it plays a role in the intracellular solubilization of fatty acids (FA). However, I-FABP has also been shown to bind to a range of non-FA ligands, including some lipophilic drug molecules, albeit with generally lower affinity than FA. The significance of these lower affinity interactions with exogenous compounds is not known. In this manuscript, we describe further characterization of drug-rat I-FABP binding interactions using a thermal-shift assay. A structural explanation of the observed affinity of rat I-FABP for different drugs based on spectroscopic data and modeling experiments is presented. In addition, immunocytochemistry has been used to probe the expression of I-FABP in a cell culture model reflective of the absorptive cells of the small intestine. Taken together, these data suggest a possible role for I-FABP in the disposition of some lipophilic drugs within the enterocyte.
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Affiliation(s)
- Tony Velkov
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, 3052, Victoria, Australia
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Swarbrick J, Iliades P, Simpson JS, Macreadie I. Folate Biosynthesis - Reappraisal of Old and Novel Targets in the Search for New Antimicrobials. ACTA ACUST UNITED AC 2008. [DOI: 10.2174/1874940200801010012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Headey SJ, Vom A, Simpson JS, Scanlon MJ. Backbone assignments of the 34 kDa ketopantoate reductase from E. coli. Biomol NMR Assign 2008; 2:93-96. [PMID: 19636932 DOI: 10.1007/s12104-008-9093-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Accepted: 04/10/2008] [Indexed: 05/28/2023]
Abstract
Ketopantoate reductase is an essential enzyme for pantothenate (vitamin B5) synthesis and a potential antibiotic target. Here we report the 15N and 1HN, 13C', 13C(alpha) and 13C(beta) chemical shift assignments of the 34 kDa ketopantoate reductase in its apo state.
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Affiliation(s)
- Stephen J Headey
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC 3052, Australia
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Abstract
The diagnosis of a primary carcinoid tumour of the breast in a 38-year-old male was initially made from a fine needle aspiration sample. The cytodiagnosis was supported by the histochemical demonstration of Grimelius-positive granules in tumour cells which were also found in tissue removed in a subsequent biopsy. An immunocytochemical study using markers for neuron-specific enolase and chromagranin in the aspirated sample and tissue was found to be negative. A total mastectomy with axillary node dissection was performed which showed no residual or metastatic tumour. No primary tumour was found elsewhere.
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Affiliation(s)
- R K Gupta
- Department of Cytology, Wellington Hospital, New Zealand
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O'Connell JL, Simpson JS, Dumanski PG, Simpson GW, Easton CJ. Aromatic chlorination of ω-phenylalkylamines and ω-phenylalkylamides in carbon tetrachloride and α,α,α-trifluorotoluene. Org Biomol Chem 2006; 4:2716-23. [PMID: 16826296 DOI: 10.1039/b605010g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aromatic halogenation of simple alkylbenzenes with chlorine proceeds smoothly in acetic acid but is much less efficient in less polar solvents. By contrast chlorination of omega-phenylalkylamines, such as 3-phenylpropylamine, occurs readily in either acetic acid, carbon tetrachloride or alpha,alpha,alpha-trifluorotoluene, and in the latter solvents gives high proportions of ortho-chlorinated products. These effects are attributable to the involvement of N-chloroamines as reaction intermediates, with intramolecular delivery of the chlorine electrophile. Omega-phenylalkylamides, such as 3-phenylpropionamide, also easily undergo aromatic chlorination in carbon tetrachloride and alpha,alpha,alpha-trifluorotoluene. These reactions generally show a first-order dependence on the substrate concentration, but not on the amount of chlorine. With carbon tetrachloride, very similar reaction rates are observed with chlorine concentrations ranging from 0.1-1.5 M. In alpha,alpha,alpha-trifluorotoluene, the rates reach a plateau at a chlorine concentration of approximately 0.2 M. These features indicate that the reactions proceed via the formation of intermediates which evidence suggests may be the corresponding O-chloroimidates. Irrespective of the mechanistic details, the reactions are remarkably rapid, being faster than analogous reactions in acetic acid and three to four orders of magnitude more rapid than reactions of simple alkylbenzenes in carbon tetrachloride. Therefore, chlorination of the amines and amides may be accomplished without the need for highly polar solvents, added catalysts or large excesses of chlorine, which are often employed for electrophilic aromatic substitutions. Although the use of carbon tetrachloride is becoming increasingly impractical due to environmental concerns, the trifluorotoluene is a suitable alternative.
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Affiliation(s)
- Jenny L O'Connell
- Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
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Philbrook A, Blake CJ, Dunlop N, Easton CJ, Keniry MA, Simpson JS. Demonstration of co-polymerization in melamine–urea–formaldehyde reactions using 15N NMR correlation spectroscopy. POLYMER 2005. [DOI: 10.1016/j.polymer.2005.01.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Gupta RK, Gaskell D, Dowle CS, Simpson JS, King BR, Naran S, Lallu S, Fauck R. The role of nipple discharge cytology in the diagnosis of breast disease: a study of 1948 nipple discharge smears from 1530 patients. Cytopathology 2004; 15:326-30. [PMID: 15606366 DOI: 10.1111/j.1365-2303.2004.00169.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study a review of 1948 nipple discharge (ND) samples from 1530 patients in the age range of 18-83 years was undertaken to determine whether cytological findings from ND smears could provide useful diagnostic information regarding various breast lesions. The study included 1494 females and 36 males and was carried out during a period of 20 years 8 months. The clinical information in all patients was obtained from clinicians (coauthors), medical records and a review of biopsies in 205 patients who had undergone surgery following the cytodiagnosis. Of the ND samples examined, 1480 were unilateral while 468 were from 234 bilateral ND. The cytodiagnoses were: benign 624, inadequate (despite two to three repeat samples) 492, inflammatory 96, papillary lesion not otherwise specified (NOS) 229, suspicious 22 (21 females, one male) and malignant 67 (63 females, four males). A breast biopsy in the 22 suspicious cases revealed breast carcinoma in 18 cases (females n = 17, male n = 1), atypical ductal hyperplasia (female n = 1), fibroadenoma (female n = 1) and a papilloma in two females. In the 67 cases with a diagnosis of malignancy 65 revealed a breast carcinoma in the biopsy (female n = 62, male n = 3) while one female was diagnosed as fibroadenoma and one male as florid gynaecomastia. In 63 cases (females n = 61; males n = 2) with clinical lumpy areas consistent with the diagnosis of fibrocystic condition in ND, the biopsy confirmed a fibrocystic process. In 53 of 229 cases with ND findings suggestive of a papillary lesion (NOS) the biopsy revealed a papilloma in 41 cases while in 12 cases no lesion was found. In the remaining cases of all the groups only a clinical follow-up and appropriate investigations were performed with no untoward outcome. Based on our study it is felt that cytological examination of ND smears seems to be a reasonably specific method in the diagnosis of malignant and suspicious cases but may be somewhat less specific for other diagnoses.
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Affiliation(s)
- R K Gupta
- The Cytology Unit, Department of Laboratory Services, Wellington Hospital and School of Medicine, Wellington, New Zealand.
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Barratt BJW, Easton CJ, Henry DJ, Li IHW, Radom L, Simpson JS. Inhibition of Peptidylglycine α-Amidating Monooxygenase by Exploitation of Factors Affecting the Stability and Ease of Formation of Glycyl Radicals. J Am Chem Soc 2004; 126:13306-11. [PMID: 15479085 DOI: 10.1021/ja046204n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptidylglycine alpha-amidating monooxygenase catalyzes the biosynthesis of peptide hormones through radical cleavage of the C-terminal glycine residues of the corresponding prohormones. We have correlated ab initio calculations of radical stabilization energies and studies of free radical brominations with the extent of catalysis displayed by peptidylglycine alpha-amidating monooxygenase, to identify classes of inhibitors of the enzyme. In particular we find that, in closely related systems, the substitution of glycolate for glycine reduces the calculated radical stabilization energy by 34.7 kJ mol(-1), decreases the rate of bromination with N-bromosuccinimide at reflux in carbon tetrachloride by a factor of at least 2000, and stops catalysis by the monooxygenase, while maintaining binding to the enzyme.
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Affiliation(s)
- Brendon J W Barratt
- Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
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Abstract
This review highlights structural and biosynthetic work on a group of nitrogen-functionalised terpenes that are almost exclusively found in marine invertebrates and the animals that feed on them. The chemical functionality reviewed includes isocyanides, isothiocyanates, formamides, thiocyanates, isocyanates, and dichloroimines. The literature through mid 2003 is reviewed and there are 143 citations.
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Affiliation(s)
- Mary J Garson
- Department of Chemistry, The University of Queensland, Brisbane 4072 QLD, Australia
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