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Shome A, Mugisho OO, Niederer RL, Rupenthal ID. Comprehensive Grading System for Experimental Autoimmune Uveitis in Mice. Biomedicines 2023; 11:2022. [PMID: 37509662 PMCID: PMC10377264 DOI: 10.3390/biomedicines11072022] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/22/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
Experimental autoimmune uveitis (EAU) is the most commonly used animal model to study the progression of chronic uveitis and to test various therapies to treat the disease. However, to accurately evaluate the effectiveness of such treatments, a grading system that combines the latest imaging techniques with definitive quantitative grading thresholds is required. This study aimed to develop a comprehensive grading system that objectively evaluates EAU progression in C57BL/6J mice. EAU was induced following immunisation with interphotoreceptor retinoid-binding protein (IRBP) and pertussis toxin. Weekly fundus and optical coherence tomography (OCT) images were acquired over 12 weeks using a Micron IV imaging system. Each mouse was graded (between 0 to 4) based on changes seen on both the fundus (optic disc, retinal blood vessels and retinal tissue) and OCT (vitreous and retinal layers) images. A total EAU response (with a maximum score of 48) was calculated for each mouse based on the sum of the individual scores each week. Analysis of the clinical scores depicted a gradual increase in inflammatory signs including optic disc and vascular swelling, leukocyte infiltration in the vitreous, lesions in the retina and formation of granulomas and hyper-reflective foci in the retinal layers in EAU mice, with most signs reaching a plateau towards the end of the study period. Development of these signs into sight-threatening complications such as optic disc atrophy, structural damage to the retina and subretinal oedema were noted in 80-90% of mice suggesting consistent disease induction. Overall, a comprehensive and objective grading system encompassing all pathologies occurring in EAU mice was developed to enhance the preclinical evaluation of novel uveitis treatments.
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Affiliation(s)
- Avik Shome
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, The New Zealand National Eye Centre, University of Auckland, Auckland 1142, New Zealand
| | - Odunayo O Mugisho
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, The New Zealand National Eye Centre, University of Auckland, Auckland 1142, New Zealand
| | - Rachael L Niederer
- Department of Ophthalmology, The New Zealand National Eye Centre, University of Auckland, Auckland 1142, New Zealand
- Te Whatu Ora Te Toka Tumai, Auckland 1142, New Zealand
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, The New Zealand National Eye Centre, University of Auckland, Auckland 1142, New Zealand
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2
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Liew LP, Shome A, Wong WW, Hong CR, Hicks KO, Jamieson SMF, Hay MP. Design, Synthesis and Anticancer Evaluation of Nitroimidazole Radiosensitisers. Molecules 2023; 28:molecules28114457. [PMID: 37298933 DOI: 10.3390/molecules28114457] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/29/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
The role of hypoxic tumour cells in resistance to radiotherapy, and in suppression of immune response, continues to endorse tumour hypoxia as a bona fide, yet largely untapped, drug target. Radiotherapy innovations such as stereotactic body radiotherapy herald new opportunities for classical oxygen-mimetic radiosensitisers. Only nimorazole is used clinically as a radiosensitiser, and there is a dearth of new radiosensitisers in development. In this report, we augment previous work to present new nitroimidazole alkylsulfonamides and we document their cytotoxicity and ability to radiosensitise anoxic tumour cells in vitro. We compare radiosensitisation with etanidazole and earlier nitroimidazole sulfonamide analogues and we identify 2-nitroimidazole and 5-nitroimidazole analogues with marked tumour radiosensitisation in ex vivo assays of surviving clonogens and with in vivo tumour growth inhibition.
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Affiliation(s)
- Lydia P Liew
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Avik Shome
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland 1023, New Zealand
- Department of Ophthalmology, The University of Auckland, Auckland 1023, New Zealand
| | - Way W Wong
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland 1023, New Zealand
| | - Cho R Hong
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Kevin O Hicks
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
| | - Stephen M F Jamieson
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland 1023, New Zealand
| | - Michael P Hay
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland 1023, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1010, New Zealand
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3
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Jamieson SM, Tsai P, Kondratyev MK, Budhani P, Liu A, Senzer NN, Chiorean EG, Jalal SI, Nemunaitis JJ, Kee D, Shome A, Wong WW, Li D, Poonawala-Lohani N, Kakadia PM, Knowlton NS, Lynch CR, Hong CR, Lee TW, Grénman RA, Caporiccio L, McKee TD, Zaidi M, Butt S, Macann AM, McIvor NP, Chaplin JM, Hicks KO, Bohlander SK, Wouters BG, Hart CP, Print CG, Wilson WR, Curran MA, Hunter FW. Evofosfamide for the treatment of human papillomavirus-negative head and neck squamous cell carcinoma. JCI Insight 2023; 8:169136. [PMID: 36810255 PMCID: PMC9990753 DOI: 10.1172/jci.insight.169136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
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4
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Mugisho OO, Aryal J, Shome A, Lyon H, Acosta ML, Green CR, Rupenthal ID. Orally Delivered Connexin43 Hemichannel Blocker, Tonabersat, Inhibits Vascular Breakdown and Inflammasome Activation in a Mouse Model of Diabetic Retinopathy. Int J Mol Sci 2023; 24:3876. [PMID: 36835288 PMCID: PMC9961562 DOI: 10.3390/ijms24043876] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/10/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023] Open
Abstract
Diabetic retinopathy (DR), a microvascular complication of diabetes, is associated with pronounced inflammation arising from the activation of a nucleotide-binding and oligomerization domain-like receptor (NLR) protein 3 (NLRP3) inflammasome. Cell culture models have shown that a connexin43 hemichannel blocker can prevent inflammasome activation in DR. The aim of this study was to evaluate the ocular safety and efficacy of tonabersat, an orally bioavailable connexin43 hemichannel blocker, to protect against DR signs in an inflammatory non-obese diabetic (NOD) DR mouse model. For retina safety studies, tonabersat was applied to retinal pigment epithelial (ARPE-19) cells or given orally to control NOD mice in the absence of any other stimuli. For efficacy studies, either tonabersat or a vehicle was given orally to the inflammatory NOD mouse model two hours before an intravitreal injection of pro-inflammatory cytokines, interleukin-1 beta, and tumour necrosis factor-alpha. Fundus and optical coherence tomography images were acquired at the baseline as well as at 2- and 7-day timepoints to assess microvascular abnormalities and sub-retinal fluid accumulation. Retinal inflammation and inflammasome activation were also assessed using immunohistochemistry. Tonabersat did not have any effect on ARPE-19 cells or control NOD mouse retinas in the absence of other stimuli. However, the tonabersat treatment in the inflammatory NOD mice significantly reduced macrovascular abnormalities, hyperreflective foci, sub-retinal fluid accumulation, vascular leak, inflammation, and inflammasome activation. These findings suggest that tonabersat may be a safe and effective treatment for DR.
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Affiliation(s)
- Odunayo O. Mugisho
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, University of Auckland, Auckland 1023, New Zealand; (O.O.M.); (J.A.); (A.S.); (H.L.); (I.D.R.)
| | - Jyoti Aryal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, University of Auckland, Auckland 1023, New Zealand; (O.O.M.); (J.A.); (A.S.); (H.L.); (I.D.R.)
| | - Avik Shome
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, University of Auckland, Auckland 1023, New Zealand; (O.O.M.); (J.A.); (A.S.); (H.L.); (I.D.R.)
| | - Heather Lyon
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, University of Auckland, Auckland 1023, New Zealand; (O.O.M.); (J.A.); (A.S.); (H.L.); (I.D.R.)
| | - Monica L. Acosta
- School of Optometry and Vision Science, University of Auckland, Auckland 1023, New Zealand;
| | - Colin R. Green
- Department of Ophthalmology, University of Auckland, Auckland 1023, New Zealand
| | - Ilva D. Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, University of Auckland, Auckland 1023, New Zealand; (O.O.M.); (J.A.); (A.S.); (H.L.); (I.D.R.)
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5
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Shome A, Mugisho OO, Niederer RL, Rupenthal ID. Blocking the inflammasome: A novel approach to treat uveitis. Drug Discov Today 2021; 26:2839-2857. [PMID: 34229084 DOI: 10.1016/j.drudis.2021.06.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/24/2021] [Accepted: 06/30/2021] [Indexed: 12/11/2022]
Abstract
Uveitis is a complex ocular inflammatory disease often accompanied by bacterial or viral infections (infectious uveitis) or underlying autoimmune diseases (non-infectious uveitis). Treatment of the underlying infection along with corticosteroid-mediated suppression of acute inflammation usually resolves infectious uveitis. However, to develop more effective therapies for non-infectious uveitis and to better address acute inflammation in infectious disease, an improved understanding of the underlying inflammatory pathways is needed. In this review, we discuss the disease aetiology, preclinical in vitro and in vivo uveitis models, the role of inflammatory pathways, as well as current and future therapies. In particular, we highlight the involvement of the inflammasome in the development of non-infectious uveitis and how it could be a future target for effective treatment of the disease.
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Affiliation(s)
- Avik Shome
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Odunayo O Mugisho
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Rachael L Niederer
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Auckland District Health Board, Auckland, New Zealand
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
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6
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Louie HH, Shome A, Kuo CY, Rupenthal ID, Green CR, Mugisho OO. Connexin43 hemichannel block inhibits NLRP3 inflammasome activation in a human retinal explant model of diabetic retinopathy. Exp Eye Res 2020; 202:108384. [PMID: 33285185 DOI: 10.1016/j.exer.2020.108384] [Citation(s) in RCA: 15] [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: 05/25/2020] [Revised: 11/24/2020] [Accepted: 11/30/2020] [Indexed: 01/26/2023]
Abstract
Diabetic retinopathy (DR), the most common ocular complication associated with diabetes, is a chronic vascular and inflammatory disease that leads to vision loss. The inflammasome pathway, a key part of the innate immune system, is required to activate chronic inflammation in DR. Unfortunately, current therapies for DR target pathological signs that are downstream of the inflammasome pathway, making them only partly effective in treating the disease. Using in vitro and in vivo DR models, it was discovered that connexin43 hemichannel blockers can inhibit activation of the inflammasome pathway. However, those studies were conducted using in vitro cell culture and in vivo animal disease models that are predictive but do not, of course, like any model, completely replicate the human condition. Here, we have developed an addition to our armamentarium of useful models, an ex vivo human organotypic retinal culture model of DR by exposing human donor retinal explants to a combination of high glucose (HG) and pro-inflammatory cytokines, interleukin-1 beta (IL-1β) and tumour necrosis factor alpha (TNF-α). We hypothesized that in this model, connexin43 hemichannel block would protect against NLRP3 inflammasome complex assembly which would in turn decrease signs of inflammation characteristic of DR. To test our hypothesis, molecular changes in the inflammatory and inflammasome pathway were assessed using immunohistochemistry and a Luminex cytokine release assay. Our results showed that the human retinal explant DR model was associated with increased inflammation and activation of the inflammasome pathway, characteristic of the human condition. Furthermore, we showed that by blocking connexin43 hemichannels with the hemichannel modulator, tonabersat, we were able to prevent NLRP3 inflammasome complex assembly, Müller cell activation, as well as release of pro-inflammatory cytokines and VEGF. This further supports the possible use of connexin43 hemichannel blockers as potential new therapies for DR.
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Affiliation(s)
- Henry H Louie
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Avik Shome
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Charisse Yj Kuo
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Ilva D Rupenthal
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Odunayo O Mugisho
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand; Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand.
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7
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Hubbard K, Shome A, Sun B, Pontré B, McGregor A, Mountjoy KG. Chronic High-Fat Diet Exacerbates Sexually Dimorphic Pomctm1/tm1 Mouse Obesity. Endocrinology 2019; 160:1081-1096. [PMID: 30997487 PMCID: PMC6469954 DOI: 10.1210/en.2018-00924] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/04/2019] [Indexed: 01/16/2023]
Abstract
Mice with a targeted mutation in the pro-opiomelanocortin (Pomc) gene (Pomctm1/tm1 mice) are unable to synthesize desacetyl-α-MSH and α-MSH and they develop obesity when fed chow diet. In this study, we hypothesized that a chronic high-fat (HF) diet exacerbates Pomctm1/tm1 mouse obesity. Male and female Pomcwt/wt and Pomctm1/tm1 mice were fed low-fat (LF) (10 kcal percent fat) or HF (45 kcal percent fat) diets from weaning for 23 weeks. We show that Pomctm1/tm1 mouse obesity is sexually dimorphic and exacerbated by an HF diet. Male Pomctm1/tm1 mice develop obesity because they are hyperphagic compared with Pomcwt/wt mice when fed an LF or HF diet. Female Pomctm1/tm1 mice develop obesity when feeding on an LF or HF diet because they exhibit signs of reduced energy expenditure (no change in feed efficiency; body weight gained exceeding energy intake) compared with Pomcwt/wt mice. A chronic HF diet exacerbates male Pomctm1/tm1 and Pomcwt/wt mouse obesity, and the increased energy intake fully accounts for increased weight gain. In contrast, female Pomcwt/wt mice are protected from chronic HF diet-induced obesity because they reduce the amount of HF diet eaten, and they appear to increase their energy expenditure (no change in feed efficiency but energy intake exceeding body weight gained). A chronic HF diet exacerbates female Pomctm1/tm1 mouse obesity due to impaired ability to reduce the amount of HF diet eaten and apparent impaired HF diet-induced adaptive thermogenesis. Our data show that desacetyl-α-MSH and α-MSH are required for sexually dimorphic HF diet-induced C57BL/6J obesity. In conclusion, desacetyl-α-MSH and α-MSH play salutary roles in sexually dimorphic melanocortin obesity and sexually dimorphic HF diet-induced C57BL/6J obesity.
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Affiliation(s)
- Kristina Hubbard
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Avik Shome
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Bo Sun
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Beau Pontré
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Ailsa McGregor
- Department of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Kathleen G Mountjoy
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Biodiscovery, University of Auckland, Auckland, New Zealand
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8
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Jamieson SM, Tsai P, Kondratyev MK, Budhani P, Liu A, Senzer NN, Chiorean EG, Jalal SI, Nemunaitis JJ, Kee D, Shome A, Wong WW, Li D, Poonawala-Lohani N, Kakadia PM, Knowlton NS, Lynch CR, Hong CR, Lee TW, Grénman RA, Caporiccio L, McKee TD, Zaidi M, Butt S, Macann AM, McIvor NP, Chaplin JM, Hicks KO, Bohlander SK, Wouters BG, Hart CP, Print CG, Wilson WR, Curran MA, Hunter FW. Evofosfamide for the treatment of human papillomavirus-negative head and neck squamous cell carcinoma. JCI Insight 2018; 3:122204. [PMID: 30135316 PMCID: PMC6141174 DOI: 10.1172/jci.insight.122204] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [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: 05/14/2018] [Accepted: 07/13/2018] [Indexed: 01/10/2023] Open
Abstract
Evofosfamide (TH-302) is a clinical-stage hypoxia-activated prodrug of a DNA-crosslinking nitrogen mustard that has potential utility for human papillomavirus (HPV) negative head and neck squamous cell carcinoma (HNSCC), in which tumor hypoxia limits treatment outcome. We report the preclinical efficacy, target engagement, preliminary predictive biomarkers and initial clinical activity of evofosfamide for HPV-negative HNSCC. Evofosfamide was assessed in 22 genomically characterized cell lines and 7 cell line-derived xenograft (CDX), patient-derived xenograft (PDX), orthotopic, and syngeneic tumor models. Biomarker analysis used RNA sequencing, whole-exome sequencing, and whole-genome CRISPR knockout screens. Five advanced/metastatic HNSCC patients received evofosfamide monotherapy (480 mg/m2 qw × 3 each month) in a phase 2 study. Evofosfamide was potent and highly selective for hypoxic HNSCC cells. Proliferative rate was a predominant evofosfamide sensitivity determinant and a proliferation metagene correlated with activity in CDX models. Evofosfamide showed efficacy as monotherapy and with radiotherapy in PDX models, augmented CTLA-4 blockade in syngeneic tumors, and reduced hypoxia in nodes disseminated from an orthotopic model. Of 5 advanced HNSCC patients treated with evofosfamide, 2 showed partial responses while 3 had stable disease. In conclusion, evofosfamide shows promising efficacy in aggressive HPV-negative HNSCC, with predictive biomarkers in development to support further clinical evaluation in this indication.
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Affiliation(s)
- Stephen Mf Jamieson
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.,Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland, New Zealand
| | - Peter Tsai
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Maria K Kondratyev
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Pratha Budhani
- Department of Immunology, University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - Arthur Liu
- Department of Immunology, University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - Neil N Senzer
- Mary Crowley Cancer Research Center, Dallas, Texas, USA
| | - E Gabriela Chiorean
- Indiana University Melvin and Bren Simon Cancer Center, Indiana University, Indianapolis, Indiana, USA.,Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington, USA
| | - Shadia I Jalal
- Indiana University Melvin and Bren Simon Cancer Center, Indiana University, Indianapolis, Indiana, USA
| | - John J Nemunaitis
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, USA
| | - Dennis Kee
- LabPLUS, Auckland City Hospital, Auckland, New Zealand
| | - Avik Shome
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Way W Wong
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Dan Li
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | | | - Purvi M Kakadia
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Nicholas S Knowlton
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.,Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Courtney Rh Lynch
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Cho R Hong
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - Tet Woo Lee
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Reidar A Grénman
- Department of Otolaryngology-Head and Neck Surgery, Turku University Hospital, Turku, Finland
| | - Laura Caporiccio
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Trevor D McKee
- STTARR Innovation Centre, University Health Network, Toronto, Ontario, Canada
| | - Mark Zaidi
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.,STTARR Innovation Centre, University Health Network, Toronto, Ontario, Canada
| | - Sehrish Butt
- STTARR Innovation Centre, University Health Network, Toronto, Ontario, Canada
| | - Andrew Mj Macann
- Department of Radiation Oncology, Auckland City Hospital, Auckland, New Zealand
| | - Nicholas P McIvor
- Department of Otolaryngology-Head and Neck Surgery, Auckland City Hospital, Auckland, New Zealand
| | - John M Chaplin
- Department of Otolaryngology-Head and Neck Surgery, Auckland City Hospital, Auckland, New Zealand
| | - Kevin O Hicks
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Stefan K Bohlander
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.,Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Bradly G Wouters
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.,Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Charles P Hart
- Threshold Pharmaceuticals, South San Francisco, California, USA
| | - Cristin G Print
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.,Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - William R Wilson
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Michael A Curran
- Department of Immunology, University of Texas, MD Anderson Cancer Center, Houston, Texas, USA
| | - Francis W Hunter
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
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9
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Bonnet M, Hong CR, Wong WW, Liew LP, Shome A, Wang J, Gu Y, Stevenson RJ, Qi W, Anderson RF, Pruijn FB, Wilson WR, Jamieson SMF, Hicks KO, Hay MP. Next-Generation Hypoxic Cell Radiosensitizers: Nitroimidazole Alkylsulfonamides. J Med Chem 2018; 61:1241-1254. [PMID: 29253343 DOI: 10.1021/acs.jmedchem.7b01678] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Innovations in the field of radiotherapy such as stereotactic body radiotherapy, along with the advent of radio-immuno-oncology, herald new opportunities for classical oxygen-mimetic radiosensitizers. The role of hypoxic tumor cells in resistance to radiotherapy and in suppression of immune response continues to endorse tumor hypoxia as a bona fide, yet largely untapped, drug target. Only nimorazole is used clinically as a radiosensitizer, and there is a dearth of new radiosensitizers in development. Here we present a survey of novel nitroimidazole alkylsulfonamides and document their cytotoxicity and ability to radiosensitize anoxic tumor cells in vitro. We use a phosphate prodrug approach to increase aqueous solubility and to improve tumor drug delivery. A 2-nitroimidazole and a 5-nitroimidazole analogue demonstrated marked tumor radiosensitization in either ex vivo assays of surviving clonogens or tumor regrowth delay.
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Affiliation(s)
- Muriel Bonnet
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand
| | - Cho Rong Hong
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand
| | - Way Wua Wong
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand
| | - Lydia P Liew
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
| | - Avik Shome
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand
| | - Jingli Wang
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand
| | - Yongchuan Gu
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
| | - Ralph J Stevenson
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand
| | - Wen Qi
- School of Chemical Sciences, Faculty of Science, University of Auckland , Private Bag 92019, Auckland, New Zealand
| | - Robert F Anderson
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,School of Chemical Sciences, Faculty of Science, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
| | - Frederik B Pruijn
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
| | - William R Wilson
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
| | - Stephen M F Jamieson
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
| | - Kevin O Hicks
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
| | - Michael P Hay
- Auckland Cancer Society Research Centre, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland , Private Bag 92019, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , 3 Symonds St, Auckland, New Zealand
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10
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Mountjoy KG, Caron A, Hubbard K, Shome A, Grey AC, Sun B, Bould S, Middleditch M, Pontré B, McGregor A, Harris PWR, Kowalczyk R, Brimble MA, Botha R, Tan KML, Piper SJ, Buchanan C, Lee S, Coll AP, Elmquist JK. Desacetyl-α-melanocyte stimulating hormone and α-melanocyte stimulating hormone are required to regulate energy balance. Mol Metab 2017; 9:207-216. [PMID: 29226825 PMCID: PMC5869732 DOI: 10.1016/j.molmet.2017.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/08/2017] [Accepted: 11/14/2017] [Indexed: 01/15/2023] Open
Abstract
Objective Regulation of energy balance depends on pro-opiomelanocortin (POMC)-derived peptides and melanocortin-4 receptor (MC4R). Alpha-melanocyte stimulating hormone (α-MSH) is the predicted natural POMC-derived peptide that regulates energy balance. Desacetyl-α-MSH, the precursor for α-MSH, is present in brain and blood. Desacetyl-α-MSH is considered to be unimportant for regulating energy balance despite being more potent (compared with α-MSH) at activating the appetite-regulating MC4R in vitro. Thus, the physiological role for desacetyl-α-MSH is still unclear. Methods We created a novel mouse model to determine whether desacetyl-α-MSH plays a role in regulating energy balance. We engineered a knock in targeted QKQR mutation in the POMC protein cleavage site that blocks the production of both desacetyl-α-MSH and α-MSH from adrenocorticotropin (ACTH1-39). Results The mutant ACTH1-39 (ACTHQKQR) functions similar to native ACTH1-39 (ACTHKKRR) at the melanocortin 2 receptor (MC2R) in vivo and MC4R in vitro. Male and female homozygous mutant ACTH1-39 (Pomctm1/tm1) mice develop the characteristic melanocortin obesity phenotype. Replacement of either desacetyl-α-MSH or α-MSH over 14 days into Pomctm1/tm1 mouse brain significantly reverses excess body weight and fat mass gained compared to wild type (WT) (Pomcwt/wt) mice. Here, we identify both desacetyl-α-MSH and α-MSH peptides as regulators of energy balance and highlight a previously unappreciated physiological role for desacetyl-α-MSH. Conclusions Based on these data we propose that there is potential to exploit the naturally occurring POMC-derived peptides to treat obesity but this relies on first understanding the specific function(s) for desacetyl-α-MSH and α-MSH. KKRR → QKQR mutation in the cleavage site of POMC prevents the production of desacetyl-α-MSH and α-MSH in mice. Male and female mutant mice develop characteristic melanocortin obesity. Central administration of α-MSH is more potent at reducing body weight in female mutant mice. Central administration of desacetyl-α-MSH and α-MSH are similarly potent at reducing body weight in male mutant mice.
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Affiliation(s)
- Kathleen G Mountjoy
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Department of Molecular Medicine and Pathology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Alexandre Caron
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kristina Hubbard
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Avik Shome
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Angus C Grey
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Department of Anatomy and Medical Imaging, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Bo Sun
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Sarah Bould
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Martin Middleditch
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Beau Pontré
- Department of Anatomy and Medical Imaging, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Ailsa McGregor
- Department of Pharmacy, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Paul W R Harris
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Renata Kowalczyk
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Margaret A Brimble
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Rikus Botha
- Department of Physiology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Karen M L Tan
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge CB2 2QR, United Kingdom
| | - Sarah J Piper
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge CB2 2QR, United Kingdom
| | - Christina Buchanan
- Department of Molecular Medicine and Pathology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Syann Lee
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Anthony P Coll
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge CB2 2QR, United Kingdom; University of Cambridge Metabolic Research Laboratories, MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, United Kingdom
| | - Joel K Elmquist
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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11
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Hunter FW, Shome A, Li D, Wong WW, Tsai P, Poonawala N, Kakadiya PM, Ketelä TM, Kondratyev MK, Lynch CR, Lee TW, Tran KB, Devaux JB, Zussman R, Hong CR, Kee D, Macann AM, Hickey AJ, Bohlander SK, Print CG, Wilson WR, Wouters BG, Jamieson SM. Abstract 169: Preclinical efficacy and sensitivity determinants of evofosfamide in molecularly defined models of head and neck squamous cell carcinoma. Cancer Res 2017. [DOI: 10.1158/1538-7445.am2017-169] [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
Tumor hypoxia is prevalent in head and neck squamous cell carcinoma (HNSCC), where it limits radiotherapy outcomes. Hypoxia-activated prodrugs (HAPs) have been developed to target hypoxic regions of tumors. These agents undergo oxygen-sensitive reductive activation, thereby delivering cytotoxic species within hypoxic cells. This study investigated the efficacy and sensitivity determinants of the clinical-stage HAP evofosfamide (TH-302) using molecularly-characterized models of HNSCC. We deployed a collection of 27 HPV-negative HNSCC cell lines derived from lesions of varying TNM stages and primary, nodal or recurrent sites. The collection was characterized for gene expression by RNA-seq, from which somatic variants were also called. Their transcriptomic features were investigated in the context of pan-cancer TCGA data by hierarchical clustering. The potency and hypoxic selectivity of 3 HAPs - evofosfamide, PR-104A and SN30000 - were assessed by antiproliferative assay in 22 lines and compared to bromo-isophosphoramide mustard (Br-IPM), cisplatin and 5-FU. The antitumor activity of evofosfamide (50 mg/kg qdx5 for 2-3 cycles with or without a single 10 Gy dose of radiation on day 5 of cycle 1) was evaluated in HNSCC xenografts in addition to a PDX isolated from an SCC of the glottic larynx. The hypoxic fraction at baseline and after 5 days of treatment was quantified by pimonidazole staining. Genetic modifiers of sensitivity to evofosfamide and its cytotoxic metabolite Br-IPM were explored through whole-genome CRISPR-Cas9 screens using the GeCKO v2 library. High-throughput screens with a custom shRNA pool were performed in one HNSCC and two pancreatic ductal adenocarcinoma cell lines to identify reductases responsible for the activation of evofosfamide in hypoxic cells. Evofosfamide was more potent and more selective for hypoxic HNSCC cells in vitro than PR-104A or SN30000. Cell line sensitivity to evofosfamide was correlated with Br-IPM and cisplatin but not with PR-104A, SN30000 or 5-FU, indicating distinct sensitivity determinants. Evidence of antitumor activity with evofosfamide was observed in vivo. CRISPR screens identified potential evofosfamide sensitivity genes that were reproducibly enriched following drug exposure. Reductase-focused RNA interference screens defined a cluster of sensitivity genes that mapped to mitochondrial electron transport, whereas shRNA’s targeted against presumed activating enzymes such as POR were not enriched. Concentration-dependent oxidation of cytochrome a and decreased respiration was observed in cells exposed to evofosfamide, suggesting reduction by mitochondrial complexes. This study provides a rationale for the clinical evaluation of evofosfamide with radiotherapy in genetically defined subsets of HNSCC patients.
Citation Format: Francis W. Hunter, Avik Shome, Dan Li, Way W. Wong, Peter Tsai, Nooriyah Poonawala, Purvi M. Kakadiya, Troy M. Ketelä, Maria K. Kondratyev, Courtney R. Lynch, Tet-Woo Lee, Khanh B. Tran, Jules B. Devaux, Rachel Zussman, Cho R. Hong, Dennis Kee, Andrew M. Macann, Anthony J. Hickey, Stefan K. Bohlander, Cristin G. Print, William R. Wilson, Bradly G. Wouters, Stephen M. Jamieson. Preclinical efficacy and sensitivity determinants of evofosfamide in molecularly defined models of head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 169. doi:10.1158/1538-7445.AM2017-169
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Affiliation(s)
| | - Avik Shome
- 1University of Auckland, Auckland, New Zealand
| | - Dan Li
- 1University of Auckland, Auckland, New Zealand
| | - Way W. Wong
- 1University of Auckland, Auckland, New Zealand
| | - Peter Tsai
- 1University of Auckland, Auckland, New Zealand
| | | | | | - Troy M. Ketelä
- 2Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | | | | | - Tet-Woo Lee
- 1University of Auckland, Auckland, New Zealand
| | | | | | | | - Cho R. Hong
- 1University of Auckland, Auckland, New Zealand
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12
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Kitzmann JP, Law L, Shome A, Muzina M, Elliott RB, Mueller KR, Schuurman HJ, Papas KK. Real-time assessment of encapsulated neonatal porcine islets prior to clinical xenotransplantation. Xenotransplantation 2012; 19:333-6. [DOI: 10.1111/xen.12005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Shome A, Hazra SK. Response of inbred and F1 hybrid embryos of mesta (Hibiscus cannabinus L.) to X-irradiation. CYTOLOGIA 1987. [DOI: 10.1508/cytologia.52.229] [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: 11/16/2022]
Affiliation(s)
- A. Shome
- Jute Agricultural Research Institute
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14
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Shome A, Bhaduri PN. Response of excised embryos of rice (Oryza sativa L.) to X-rays. Theor Appl Genet 1982; 61:135-139. [PMID: 24270335 DOI: 10.1007/bf00273881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/1981] [Accepted: 05/08/1981] [Indexed: 06/02/2023]
Abstract
The response of rice (Oryza sativa L.) embryos to X-rays (M1 to M3) was studied. By means of irradiating excised embryos, both chlorophyll and macromutation were successfully induced in three genotypes of rice. However, differential responses in terms of mutation frequency, mutation spectrum and optimal levels of X-rays required for induction of mutation (chlorophyll as well as morphological) were found to exist between cultivars. In 'Satika' and 'Ashkhata', LD50 values and maximum induced seed sterility are concomitant to optimum level of radiation required for triggering chlorophyll mutation. However, optimum dose for induction of macromutation in 'Satika' and 'Kerangserang' is independent of either LD50 and/or induced seed sterility.Chances of obtaining both dominant and locus specific recessive mutations in the immediate X-ray treated generation (M1) are large. This indicates the very high degree of effectiveness of the excised embryo irradiation technique with rice.
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Affiliation(s)
- A Shome
- Department of Botany, Burdwan University, Burdwan, W. Bengal, India
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15
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Shome A. X-ray irradiation of excised embryos of mesta (Hibiscus cannabinus L. and H. sabdariffa L.). Theor Appl Genet 1981; 59:11-15. [PMID: 24276322 DOI: 10.1007/bf00275767] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/1980] [Accepted: 07/11/1980] [Indexed: 06/02/2023]
Abstract
Excised embryos of Hibiscus spp. were treated with 1 kR to 6 kR of X-ray. Results indicate that germination was unaffected at this level of employed doses in both species, which in turn implies that the factors responsible for inhibition of germination are not present in the embryo. LD50 values differed between varieties and species. Early varieties of both species were more sensitive to radiation than late varieties. Strikingly similar effects were observed for the varieties with smaller embryos over those with larger ones. Allopolyploid H. sabdariffa (2n=72) was more susceptible than diploid H. cannabinus (2n=36).Differences in mutation frequency exist between species with different levels of ploidy and between varieties within the same species. Most of the HC mesta varieties yielded higher mutation frequencies than those of HS mesta. Optimal dose for triggering mutations in all varieties (except the chlorophyll mutation variety of HC mesta) of the two species lies within a narrow range of 1 kR to 2 kR. Cent per cent seedling abnormalities is concomitant to LD50; nevertheless, optimum dose for mutation frequency is independent of LD50. Hence, the response should be viewed in terms of respective genotype. The advantages of the embryo irradiation technique are mentioned.
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Affiliation(s)
- A Shome
- Jute Agricultural Research Institute, Barrackpore, West Bengal, India
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16
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Affiliation(s)
- A. Shome
- Department of Botany, University of Burdwan
- Jute Agricultural Research Institute
| | - P. N. Bhaduri
- Department of Botany, University of Burdwan
- Emeritus Scientist (ICAR), B.C.K. Viswa Vidyalaya
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