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Boyce RW, Brown D, Felx M, Mellal N, Locher K, Pyrah I, Ominsky MS, Taylor S. Decreased osteoprogenitor proliferation precedes attenuation of cancellous bone formation in ovariectomized rats treated with sclerostin antibody. Bone Rep 2018; 8:90-94. [PMID: 29955626 PMCID: PMC6020110 DOI: 10.1016/j.bonr.2018.03.001] [Citation(s) in RCA: 23] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 02/15/2018] [Accepted: 03/02/2018] [Indexed: 02/03/2023] Open
Abstract
Sclerostin antibody (Scl-Ab) stimulates bone formation, which with long-term treatment, attenuates over time. The cellular and molecular mechanisms responsible for the attenuation of bone formation are not well understood, but in aged ovariectomized (OVX) rats, the reduction in vertebral cancellous bone formation is preceded by a reduction in osteoprogenitor (OP) number and significant induction of signaling pathways known to suppress mitogenesis and cell cycle progression in the osteocyte (OCy) (Taylor et al., 2016). To determine if the reduction in OP number is associated with a decrease in proliferation, aged OVX rats were administered vehicle or Scl-Ab for 9 or 29 days and implanted with continuous-delivery 5-bromo-2′-deoxyuridine (BrdU) mini-osmotic pumps 5 days prior to necropsy. The total number of BrdU-labeled osteoblasts (OB) was quantified in vertebral cancellous bone to indirectly assess the effects of Scl-Ab treatment on OP proliferation at the time of activation of modeling-based bone formation at day 9 and at the time of maximal mineralizing surface, initial decrease in OP number, and transcriptional changes in the OCy at day 29. Compared with vehicle, Scl-Ab resulted in an increase in the total number of BrdU-positive OB (+260%) at day 9 that decreased with continued treatment (+50%) at day 29. These differences in proliferation occurred at time points when the increase in total OB number was significant and similar in magnitude. These findings suggest that reduced OP proliferation contributes to the decrease in OP numbers, an effect that would limit the OB pool and contribute to the attenuation of bone formation that occurs with long-term Scl-Ab treatment. Sclerostin antibody stimulates bone formation (BF) that attenuates over time. Osteoprogenitor (OP) proliferation increases early with treatment. Attenuation of BF is preceded by a decrease in OP proliferation. Decrease is coincident with molecular signaling consistent with cell cycle arrest. Decreased OP proliferation contributes to the attenuation of BF.
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Key Words
- ANOVA, analysis of variance
- Anabolics
- Bone
- BrdU, 5-bromo-2′-deoxyuridine
- CDKN1A, cyclin-dependent kinase inhibitor 1A
- CDKN2A, CDKN inhibitor 2A
- CE, coefficient of error
- CV, coefficient of variation
- Cell signaling
- D, day
- E2F1, E2F transcription factor 1
- FOXM1, Forkhead box protein M1
- MS/BS, mineralizing surface per bone surface
- MYC, v-myc avian myelocytomatosis viral oncogene homolog
- MYCN, MYC neuroblastoma-derived homolog
- OB, osteoblast(s)
- OCy, osteocyte(s)
- OP, osteoprogenitor(s)
- OVX, ovariectomized
- Ob.N, OB number
- Osteoporosis
- Osteoprogenitors
- PROBE, precision range of an optimally balanced estimator
- RB1, retinoblastoma protein 1
- RUNX2, Runt-related transcription factor 2
- SURS, systematic uniform random sampling
- Scl-Ab, sclerostin antibody
- Scl-AbVI, 50 mg/kg of a Scl-Ab
- TP53, tumor protein p53
- VEH, vehicle
- Wnt signaling
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Affiliation(s)
- Rogely Waite Boyce
- Department of Comparative Biology and Safety Sciences, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, United States
| | - Danielle Brown
- Charles River Laboratories, 4025 Stirrup Creek Drive, Suite 150, Durham, NC 27703, United States
| | - Melanie Felx
- Charles River Laboratories, 22022 Transcanadienne, Senneville, QC H9X 3R3, Canada
| | - Nacera Mellal
- Charles River Laboratories, 22022 Transcanadienne, Senneville, QC H9X 3R3, Canada
| | - Kathrin Locher
- Department of Comparative Biology and Safety Sciences, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, United States
| | - Ian Pyrah
- Department of Comparative Biology and Safety Sciences, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, United States
| | - Michael S Ominsky
- Department of CardioMetabolic Disorders, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, United States
| | - Scott Taylor
- Department of Comparative Biology and Safety Sciences, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, United States
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Jolette J, Attalla B, Varela A, Long GG, Mellal N, Trimm S, Smith SY, Ominsky MS, Hattersley G. Comparing the incidence of bone tumors in rats chronically exposed to the selective PTH type 1 receptor agonist abaloparatide or PTH(1-34). Regul Toxicol Pharmacol 2017; 86:356-365. [PMID: 28389324 DOI: 10.1016/j.yrtph.2017.04.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [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: 10/27/2016] [Revised: 03/29/2017] [Accepted: 04/02/2017] [Indexed: 02/03/2023]
Abstract
Prolonged treatment with human parathyroid hormone (hPTH) in rats results in development of bone tumors, though this finding has not been supported by clinical experience. The PTH type 1 receptor agonist abaloparatide, selected for its bone anabolic activity, is under clinical development to treat postmenopausal women with osteoporosis. To determine the carcinogenic potential of abaloparatide, Fischer (F344) rats were administered SC daily abaloparatide at doses of 0, 10, 25, and 50 μg/kg or 30 μg/kg hPTH(1-34) as a positive control for up to 2 years. Robust increases in bone density were achieved at all abaloparatide doses and with hPTH(1-34). Comprehensive histopathological analysis reflected a comparable continuum of proliferative changes in bone, mostly osteosarcoma, in both abaloparatide and hPTH(1-34) treated rats. Comparing the effects of abaloparatide and hPTH(1-34) at the 25 and 30 μg/kg respective doses, representing similar exposure multiples to the human therapeutic doses, revealed similar osteosarcoma-associated mortality, tumor incidence, age at first occurrence, and metastatic potential. There were no increases in the incidence of non-bone tumors with abaloparatide compared to vehicle. Thus, near life-long treatment with abaloparatide in rats resulted in dose and time dependent formation of osteosarcomas, with a comparable response to hPTH(1-34) at similar exposure.
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Affiliation(s)
- Jacquelin Jolette
- Charles River Laboratories, Preclinical Services, Montreal, 22022 Transcanadienne, Senneville, Quebec H9X 3R3, Canada
| | - Bassem Attalla
- Charles River Laboratories, Preclinical Services, Montreal, 22022 Transcanadienne, Senneville, Quebec H9X 3R3, Canada
| | - Aurore Varela
- Charles River Laboratories, Preclinical Services, Montreal, 22022 Transcanadienne, Senneville, Quebec H9X 3R3, Canada
| | - Gerald G Long
- Experimental Pathology Laboratories Inc., Sterling, VA 20166, USA
| | - Nacera Mellal
- Charles River Laboratories, Preclinical Services, Montreal, 22022 Transcanadienne, Senneville, Quebec H9X 3R3, Canada
| | - Sabile Trimm
- Charles River Laboratories, Preclinical Services, Montreal, 22022 Transcanadienne, Senneville, Quebec H9X 3R3, Canada
| | - Susan Y Smith
- Charles River Laboratories, Preclinical Services, Montreal, 22022 Transcanadienne, Senneville, Quebec H9X 3R3, Canada
| | | | - Gary Hattersley
- Radius Health, Inc., 950 Winter Street, Waltham, MA 02451, USA.
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Ominsky MS, Boyd SK, Varela A, Jolette J, Felx M, Doyle N, Mellal N, Smith SY, Locher K, Buntich S, Pyrah I, Boyce RW. Romosozumab Improves Bone Mass and Strength While Maintaining Bone Quality in Ovariectomized Cynomolgus Monkeys. J Bone Miner Res 2017; 32:788-801. [PMID: 27865001 DOI: 10.1002/jbmr.3036] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/03/2016] [Accepted: 11/05/2016] [Indexed: 11/11/2022]
Abstract
Romosozumab (Romo), a humanized sclerostin antibody, is a bone-forming agent under development for treatment of osteoporosis. To examine the effects of Romo on bone quality, mature cynomolgus monkeys (cynos) were treated 4 months post- ovariectomy (OVX) with vehicle, 3 mg/kg, or 30 mg/kg Romo for 12 months, or with 30 mg/kg Romo for 6 months followed by vehicle for 6 months (30/0). Serum bone formation markers were increased by Romo during the first 6 months, corresponding to increased cancellous, endocortical, and periosteal bone formation in rib and iliac biopsies at months 3 and 6. Dual-energy X-ray absorptiometry (DXA) bone mineral density (BMD) was increased by 14% to 26% at the lumbar spine and proximal femur at month 12, corresponding to significant increases in bone strength at 3 and 30 mg/kg in lumbar vertebral bodies and cancellous cores, and at 30 mg/kg in the femur diaphysis and neck. Bone mass remained positively correlated with strength at these sites, with no changes in calculated material properties at cortical sites. These bone-quality measures were also maintained in the 30/0 group, despite a gradual loss of accrued bone mass. Normal bone mineralization was confirmed by histomorphometry and ash analyses. At the radial diaphysis, a transient, reversible 2% reduction in cortical BMD was observed with Romo at month 6, despite relative improvements in bone mineral content (BMC). High-resolution pQCT confirmed this decline in cortical BMD at the radial diaphysis and metaphysis in a second set of OVX cynos administered 3 mg/kg Romo for 6 months. Radial diaphyseal strength was maintained and metaphyseal strength improved with Romo as estimated by finite element modeling. Decreased radial cortical BMD was a consequence of increased intracortical remodeling, with no increase in cortical porosity. Romo resulted in marked improvements in bone mass, architecture, and bone strength, while maintaining bone quality in OVX cynos, supporting its bone efficacy and safety profile. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
| | - Steven K Boyd
- Department of Radiology and McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Canada
| | - Aurore Varela
- Charles River Laboratories Preclinical Services, Montreal, Canada
| | | | - Melanie Felx
- Charles River Laboratories Preclinical Services, Montreal, Canada
| | - Nancy Doyle
- Charles River Laboratories Preclinical Services, Montreal, Canada
| | - Nacera Mellal
- Charles River Laboratories Preclinical Services, Montreal, Canada
| | - Susan Y Smith
- Charles River Laboratories Preclinical Services, Montreal, Canada
| | - Kathrin Locher
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Sabina Buntich
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Ian Pyrah
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Rogely W Boyce
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
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Laffins MM, Mellal N, Almlie CL, Regalia DE. Evaluation of Infrared Thermometry in Cynomolgus Macaques ( Macaca fascicularis). J Am Assoc Lab Anim Sci 2017; 56:84-89. [PMID: 28905720 PMCID: PMC5250500] [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] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/03/2016] [Accepted: 07/01/2016] [Indexed: 06/07/2023]
Abstract
Recording an accurate body temperature is important to assess an animal's health status. We compared temperature data from sedated cynomolgus macaques (Macaca fascicularis) to evaluate differences between rectal, infrared (inguinal and chest), and implanted telemetry techniques with the objective of demonstrating the diagnostic equivalence of the infrared device with other approaches. Infrared thermometer readings are instantaneous and require no contact with the animal. Body temperature data were obtained from 205 (137 male, 68 female) cynomolgus macaques under ketamine (10 mg/kg IM) sedation over a 3-mo period during scheduled physical examinations. Infrared measurements were taken 5 cm from the chest and inguinal areas. We evaluated 10 (9 functional devices) sedated cynomolgus macaques (5 male, 5 female) implanted with telemetry units in a muscular pouch between the internal and external abdominal oblique muscles. We determined that the mean body temperature acquired by using telemetry did not differ from either the mean of inguinal and chest infrared measurements but did differ from the mean of temperature obtained rectally. In addition, the mean rectal temperature differed from the mean of the inguinal reading but not the mean of the chest temperature. The results confirm our hypothesis that the infrared thermometer can be used to replace standard rectal thermometry.
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Affiliation(s)
| | - Nacera Mellal
- Charles River Laboratories, Montreal, Quebec, Canada, USA
| | - Cynthia L Almlie
- Lab Animal Medicine, Charles River Laboratories, Reno, Nevada, USA
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Chouinard L, Felx M, Mellal N, Varela A, Mann P, Jolette J, Samadfam R, Smith SY, Locher K, Buntich S, Ominsky MS, Pyrah I, Boyce RW. Carcinogenicity risk assessment of romosozumab: A review of scientific weight-of-evidence and findings in a rat lifetime pharmacology study. Regul Toxicol Pharmacol 2016; 81:212-222. [PMID: 27569204 DOI: 10.1016/j.yrtph.2016.08.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [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: 06/28/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 12/31/2022]
Abstract
Romosozumab is a humanized immunoglobulin G2 monoclonal antibody that binds and blocks the action of sclerostin, a protein secreted by the osteocyte and an extracellular inhibitor of canonical Wnt signaling. Blockade of sclerostin binding to low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and LRP6) allows Wnt ligands to activate canonical Wnt signaling in bone, increasing bone formation and decreasing bone resorption, making sclerostin an attractive target for osteoporosis therapy. Because romosozumab is a bone-forming agent and an activator of canonical Wnt signaling, questions have arisen regarding a potential carcinogenic risk. Weight-of-evidence factors used in the assessment of human carcinogenic risk of romosozumab included features of canonical Wnt signaling, expression pattern of sclerostin, phenotype of loss-of-function mutations in humans and mice, mode and mechanism of action of romosozumab, and findings from romosozumab chronic toxicity studies in rats and monkeys. Although the weight-of-evidence factors supported that romosozumab would pose a low carcinogenic risk to humans, the carcinogenic potential of romosozumab was assessed in a rat lifetime study. There were no romosozumab-related effects on tumor incidence in rats. The findings of the lifetime study and the weight-of-evidence factors collectively indicate that romosozumab administration would not pose a carcinogenic risk to humans.
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Affiliation(s)
- Luc Chouinard
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Melanie Felx
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Nacera Mellal
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Aurora Varela
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Peter Mann
- EPL NorthWest, 600 North 36th Street, Suite 220, Seattle, WA, 98103, USA
| | - Jacquelin Jolette
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Rana Samadfam
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Susan Y Smith
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Kathrin Locher
- One Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - Sabina Buntich
- One Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | | | - Ian Pyrah
- One Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA, 91320, USA
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