1
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Lane IC, Kembuan G, Carreiro J, Kann MC, Lin W, Bouffard AA, Kreuzer J, Morris R, Schneider EM, Kim JY, Zou C, Salas-Benito D, Gasser JA, Leick MB, Słabicki M, Haas W, Maus MV, Jan M. Genetic retargeting of E3 ligases to enhance CAR T cell therapy. Cell Chem Biol 2024; 31:338-348.e5. [PMID: 37989314 PMCID: PMC10922718 DOI: 10.1016/j.chembiol.2023.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 08/09/2023] [Accepted: 10/27/2023] [Indexed: 11/23/2023]
Abstract
Chimeric antigen receptor (CAR) T cell therapies are medical breakthroughs in cancer treatment. However, treatment failure is often caused by CAR T cell dysfunction. Additional approaches are needed to overcome inhibitory signals that limit anti-tumor potency. Here, we developed bifunctional fusion "degrader" proteins that bridge one or more target proteins and an E3 ligase complex to enforce target ubiquitination and degradation. Conditional degradation strategies were developed using inducible degrader transgene expression or small molecule-dependent E3 recruitment. We further engineered degraders to block SMAD-dependent TGFβ signaling using a domain from the SARA protein to target both SMAD2 and SMAD3. SMAD degrader CAR T cells were less susceptible to suppression by TGFβ and demonstrated enhanced anti-tumor potency in vivo. These results demonstrate a clinically suitable synthetic biology platform to reprogram E3 ligase target specificity for conditional, multi-specific endogenous protein degradation, with promising applications including enhancing the potency of CAR T cell therapy.
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Affiliation(s)
- Isabel C Lane
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Gabriele Kembuan
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Jeannie Carreiro
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Michael C Kann
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Cellular Immunotherapy Program, Cancer Center, Massachusetts General Hospital, Boston, MA, USA
| | - William Lin
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Amanda A Bouffard
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Cellular Immunotherapy Program, Cancer Center, Massachusetts General Hospital, Boston, MA, USA
| | - Johannes Kreuzer
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Robert Morris
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | | | - Joanna Y Kim
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Charles Zou
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Diego Salas-Benito
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Cellular Immunotherapy Program, Cancer Center, Massachusetts General Hospital, Boston, MA, USA
| | - Jessica A Gasser
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Mark B Leick
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Cellular Immunotherapy Program, Cancer Center, Massachusetts General Hospital, Boston, MA, USA
| | - Mikołaj Słabicki
- Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Wilhelm Haas
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Marcela V Maus
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA; Cellular Immunotherapy Program, Cancer Center, Massachusetts General Hospital, Boston, MA, USA
| | - Max Jan
- Cancer Center, Massachusetts General Hospital, Boston, MA, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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2
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Sellar RS, Sperling AS, Słabicki M, Gasser JA, McConkey ME, Donovan KA, Mageed N, Adams DN, Zou C, Miller PG, Dutta RK, Boettcher S, Lin AE, Sandoval B, Quevedo Barrios VA, Kovalcik V, Koeppel J, Henderson EK, Fink EC, Yang L, Chan A, Pokharel SP, Bergstrom EJ, Burt R, Udeshi ND, Carr SA, Fischer ES, Chen CW, Ebert BL. Degradation of GSPT1 causes TP53-independent cell death in leukemia while sparing normal hematopoietic stem cells. J Clin Invest 2022; 132:e153514. [PMID: 35763353 PMCID: PMC9374383 DOI: 10.1172/jci153514] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 06/24/2022] [Indexed: 11/17/2022] Open
Abstract
Targeted protein degradation is a rapidly advancing and expanding therapeutic approach. Drugs that degrade GSPT1 via the CRL4CRBN ubiquitin ligase are a new class of cancer therapy in active clinical development with evidence of activity against acute myeloid leukemia in early-phase trials. However, other than activation of the integrated stress response, the downstream effects of GSPT1 degradation leading to cell death are largely undefined, and no murine models are available to study these agents. We identified the domains of GSPT1 essential for cell survival and show that GSPT1 degradation leads to impaired translation termination, activation of the integrated stress response pathway, and TP53-independent cell death. CRISPR/Cas9 screens implicated decreased translation initiation as protective following GSPT1 degradation, suggesting that cells with higher levels of translation are more susceptible to the effects of GSPT1 degradation. We defined 2 Crbn amino acids that prevent Gspt1 degradation in mice, generated a knockin mouse with alteration of these residues, and demonstrated the efficacy of GSPT1-degrading drugs in vivo with relative sparing of numbers and function of long-term hematopoietic stem cells. Our results provide a mechanistic basis for the use of GSPT1 degraders for the treatment of cancer, including TP53-mutant acute myeloid leukemia.
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Affiliation(s)
- Rob S. Sellar
- Department of Haematology, UCL Cancer Institute, University College London, London, United Kingdom
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Adam S. Sperling
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Division of Hematology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Mikołaj Słabicki
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Jessica A. Gasser
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Marie E. McConkey
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Katherine A. Donovan
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Nada Mageed
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Dylan N. Adams
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Charles Zou
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Peter G. Miller
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Ravi K. Dutta
- Division of Hematology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Steffen Boettcher
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Medical Oncology and Hematology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Amy E. Lin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Brittany Sandoval
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | | | - Veronica Kovalcik
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Jonas Koeppel
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Elizabeth K. Henderson
- Department of Haematology, UCL Cancer Institute, University College London, London, United Kingdom
| | - Emma C. Fink
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Lu Yang
- Department of Systems Biology, City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Anthony Chan
- Department of Systems Biology, City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Sheela Pangeni Pokharel
- Department of Systems Biology, City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | | | - Rajan Burt
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | | | - Steven A. Carr
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Eric S. Fischer
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Chun-Wei Chen
- Department of Systems Biology, City of Hope Comprehensive Cancer Center, Duarte, California, USA
| | - Benjamin L. Ebert
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
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3
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Renneville A, Gasser JA, Grinshpun DE, Jean Beltran PM, Udeshi ND, Matyskiela ME, Clayton T, McConkey M, Viswanathan K, Tepper A, Guirguis AA, Sellar RS, Cotteret S, Marzac C, Saada V, De Botton S, Kiladjian JJ, Cayuela JM, Rolfe M, Chamberlain PP, Carr SA, Ebert BL. Avadomide induces degradation of ZMYM2 fusion oncoproteins in hematologic malignancies. Blood Cancer Discov 2021; 2:250-265. [PMID: 34027417 DOI: 10.1158/2643-3230.bcd-20-0105] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Thalidomide analogs exert their therapeutic effects by binding to the CRL4CRBN E3 ubiquitin ligase, promoting ubiquitination and subsequent proteasomal degradation of specific protein substrates. Drug-induced degradation of IKZF1 and IKZF3 in B-cell malignancies demonstrates the clinical utility of targeting disease-relevant transcription factors for degradation. Here, we found that avadomide (CC-122) induces CRBN-dependent ubiquitination and proteasomal degradation of ZMYM2 (ZNF198), a transcription factor involved in balanced chromosomal rearrangements with FGFR1 and FLT3 in aggressive forms of hematologic malignancies. The minimal drug-responsive element of ZMYM2 is a zinc-chelating MYM domain and is contained in the N-terminal portion of ZMYM2 that is universally included in the derived fusion proteins. We demonstrate that avadomide has the ability to induce proteasomal degradation of ZMYM2-FGFR1 and ZMYM2-FLT3 chimeric oncoproteins, both in vitro and in vivo. Our findings suggest that patients with hematologic malignancies harboring these ZMYM2 fusion proteins may benefit from avadomide treatment.
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Affiliation(s)
- Aline Renneville
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,INSERM U1287, Gustave Roussy Cancer Campus, Villejuif, France
| | - Jessica A Gasser
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Daniel E Grinshpun
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | | | - Namrata D Udeshi
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Mary E Matyskiela
- Celgene/Bristol-Myers Squibb corporation, San Diego, California, USA
| | - Thomas Clayton
- Celgene/Bristol-Myers Squibb corporation, San Diego, California, USA
| | - Marie McConkey
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Kaushik Viswanathan
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Alexander Tepper
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Andrew A Guirguis
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Rob S Sellar
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,Department of Haematology, UCL Cancer Institute, London, United Kingdom
| | - Sophie Cotteret
- Département de Biologie et Pathologie, Gustave Roussy Cancer Campus, Villejuif, France
| | - Christophe Marzac
- Département de Biologie et Pathologie, Gustave Roussy Cancer Campus, Villejuif, France
| | - Véronique Saada
- Département de Biologie et Pathologie, Gustave Roussy Cancer Campus, Villejuif, France
| | - Stéphane De Botton
- Département d'Hématologie, Gustave Roussy Cancer Campus, Villejuif, France
| | - Jean-Jacques Kiladjian
- Université de Paris, AP-HP, Hôpital Saint-Louis, Centre d'Investigations Cliniques CIC 1427, INSERM, Paris, France
| | - Jean-Michel Cayuela
- Hematology Laboratory and EA3518, University Hospital Saint-Louis, Université de Paris, Paris, France
| | - Mark Rolfe
- Celgene/Bristol-Myers Squibb corporation, San Diego, California, USA
| | | | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Benjamin L Ebert
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
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4
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Jan M, Scarfò I, Larson RC, Walker A, Schmidts A, Guirguis AA, Gasser JA, Słabicki M, Bouffard AA, Castano AP, Kann MC, Cabral ML, Tepper A, Grinshpun DE, Sperling AS, Kyung T, Sievers QL, Birnbaum ME, Maus MV, Ebert BL. Reversible ON- and OFF-switch chimeric antigen receptors controlled by lenalidomide. Sci Transl Med 2021; 13:eabb6295. [PMID: 33408186 PMCID: PMC8045771 DOI: 10.1126/scitranslmed.abb6295] [Citation(s) in RCA: 119] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 08/19/2020] [Accepted: 09/30/2020] [Indexed: 12/12/2022]
Abstract
Cell-based therapies are emerging as effective agents against cancer and other diseases. As autonomous "living drugs," these therapies lack precise control. Chimeric antigen receptor (CAR) T cells effectively target hematologic malignancies but can proliferate rapidly and cause toxicity. We developed ON and OFF switches for CAR T cells using the clinically approved drug lenalidomide, which mediates the proteasomal degradation of several target proteins by inducing interactions between the CRL4CRBN E3 ubiquitin ligase and a C2H2 zinc finger degron motif. We performed a systematic screen to identify "super-degron" tags with enhanced sensitivity to lenalidomide-induced degradation and used these degradable tags to generate OFF-switch degradable CARs. To create an ON switch, we engineered a lenalidomide-inducible dimerization system and developed split CARs that required both lenalidomide and target antigen for activation. Subtherapeutic lenalidomide concentrations controlled the effector functions of ON- and OFF-switch CAR T cells. In vivo, ON-switch split CARs demonstrated lenalidomide-dependent antitumor activity, and OFF-switch degradable CARs were depleted by drug treatment to limit inflammatory cytokine production while retaining antitumor efficacy. Together, the data showed that these lenalidomide-gated switches are rapid, reversible, and clinically suitable systems to control transgene function in diverse gene- and cell-based therapies.
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Affiliation(s)
- Max Jan
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Irene Scarfò
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Rebecca C Larson
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Amanda Walker
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Andrea Schmidts
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Andrew A Guirguis
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Jessica A Gasser
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Mikołaj Słabicki
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Amanda A Bouffard
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Ana P Castano
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Michael C Kann
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Maria L Cabral
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Alexander Tepper
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Daniel E Grinshpun
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Adam S Sperling
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Taeyoon Kyung
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | | | - Michael E Birnbaum
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Marcela V Maus
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
- Cellular Immunotherapy Program, Massachusetts General Hospital Cancer Center, Charlestown, MA 02114, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Benjamin L Ebert
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
- Howard Hughes Medical Institute, Dana-Farber Cancer Institute, Boston, MA 02215, USA
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5
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Słabicki M, Kozicka Z, Petzold G, Li YD, Manojkumar M, Bunker RD, Donovan KA, Sievers QL, Koeppel J, Suchyta D, Sperling AS, Fink EC, Gasser JA, Wang LR, Corsello SM, Sellar RS, Jan M, Gillingham D, Scholl C, Fröhling S, Golub TR, Fischer ES, Thomä NH, Ebert BL. The CDK inhibitor CR8 acts as a molecular glue degrader that depletes cyclin K. Nature 2020; 585:293-297. [PMID: 32494016 PMCID: PMC7486275 DOI: 10.1038/s41586-020-2374-x] [Citation(s) in RCA: 192] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 04/29/2020] [Indexed: 12/16/2022]
Abstract
Molecular glue compounds induce protein-protein interactions that, in the context of a ubiquitin ligase, lead to protein degradation1. Unlike traditional enzyme inhibitors, these molecular glue degraders act substoichiometrically to catalyse the rapid depletion of previously inaccessible targets2. They are clinically effective and highly sought-after, but have thus far only been discovered serendipitously. Here, through systematically mining databases for correlations between the cytotoxicity of 4,518 clinical and preclinical small molecules and the expression levels of E3 ligase components across hundreds of human cancer cell lines3-5, we identify CR8-a cyclin-dependent kinase (CDK) inhibitor6-as a compound that acts as a molecular glue degrader. The CDK-bound form of CR8 has a solvent-exposed pyridyl moiety that induces the formation of a complex between CDK12-cyclin K and the CUL4 adaptor protein DDB1, bypassing the requirement for a substrate receptor and presenting cyclin K for ubiquitination and degradation. Our studies demonstrate that chemical alteration of surface-exposed moieties can confer gain-of-function glue properties to an inhibitor, and we propose this as a broader strategy through which target-binding molecules could be converted into molecular glues.
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Affiliation(s)
- Mikołaj Słabicki
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Division of Translational Medical Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Zuzanna Kozicka
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Georg Petzold
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Yen-Der Li
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Manisha Manojkumar
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Division of Translational Medical Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Richard D Bunker
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Monte Rosa Therapeutics, Basel, Switzerland
| | - Katherine A Donovan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Quinlan L Sievers
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jonas Koeppel
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Division of Translational Medical Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Dakota Suchyta
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Faculty of Science, University of Basel, Basel, Switzerland
| | - Adam S Sperling
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Emma C Fink
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jessica A Gasser
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Li R Wang
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Steven M Corsello
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Rob S Sellar
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Haematology, UCL Cancer Institute, University College London, London, UK
| | - Max Jan
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | | | - Claudia Scholl
- Division of Applied Functional Genomics, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Stefan Fröhling
- Division of Translational Medical Oncology, German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Heidelberg, Germany
- German Cancer Consortium, Heidelberg, Germany
| | - Todd R Golub
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Howard Hughes Medical Institute, Boston, MA, USA
| | - Eric S Fischer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Nicolas H Thomä
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
| | - Benjamin L Ebert
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Howard Hughes Medical Institute, Boston, MA, USA.
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6
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Udeshi ND, Mani DC, Satpathy S, Fereshetian S, Gasser JA, Svinkina T, Olive ME, Ebert BL, Mertins P, Carr SA. Rapid and deep-scale ubiquitylation profiling for biology and translational research. Nat Commun 2020; 11:359. [PMID: 31953384 PMCID: PMC6969155 DOI: 10.1038/s41467-019-14175-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 12/19/2019] [Indexed: 11/21/2022] Open
Abstract
Protein ubiquitylation is involved in a plethora of cellular processes. While antibodies directed at ubiquitin remnants (K-ɛ-GG) have improved the ability to monitor ubiquitylation using mass spectrometry, methods for highly multiplexed measurement of ubiquitylation in tissues and primary cells using sub-milligram amounts of sample remains a challenge. Here, we present a highly sensitive, rapid and multiplexed protocol termed UbiFast for quantifying ~10,000 ubiquitylation sites from as little as 500 μg peptide per sample from cells or tissue in a TMT10plex in ca. 5 h. High-field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) is used to improve quantitative accuracy for posttranslational modification analysis. We use the approach to rediscover substrates of the E3 ligase targeting drug lenalidomide and to identify proteins modulated by ubiquitylation in models of basal and luminal human breast cancer. The sensitivity and speed of the UbiFast method makes it suitable for large-scale studies in primary tissue samples. Comprehensive protein ubiquitylation profiling by mass spectrometry typically requires large sample amounts, limiting its applicability to tissue samples. Here, the authors present an optimized proteomics method that enables multiplexed ubiquitylome analysis of cells and tumor tissue samples.
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Affiliation(s)
| | - Deepak C Mani
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | | | | | - Jessica A Gasser
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Division of Hematology, Brigham and Women's Hospital, Boston, MA, 02115, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Tanya Svinkina
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Meagan E Olive
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Benjamin L Ebert
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Division of Hematology, Brigham and Women's Hospital, Boston, MA, 02115, USA.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.,Howard Hughes Medical Institute, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Philipp Mertins
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.,Max Delbrück Center for Molecular Medicine in the Helmholtz Society, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
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7
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Sperling AS, Burgess M, Keshishian H, Gasser JA, Bhatt S, Jan M, Słabicki M, Sellar RS, Fink EC, Miller PG, Liddicoat BJ, Sievers QL, Sharma R, Adams DN, Olesinski EA, Fulciniti M, Udeshi ND, Kuhn E, Letai A, Munshi NC, Carr SA, Ebert BL. Patterns of substrate affinity, competition, and degradation kinetics underlie biological activity of thalidomide analogs. Blood 2019; 134:160-170. [PMID: 31043423 PMCID: PMC6624968 DOI: 10.1182/blood.2019000789] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 04/26/2019] [Indexed: 12/15/2022] Open
Abstract
Pharmacologic agents that modulate ubiquitin ligase activity to induce protein degradation are a major new class of therapeutic agents, active in a number of hematologic malignancies. However, we currently have a limited understanding of the determinants of activity of these agents and how resistance develops. We developed and used a novel quantitative, targeted mass spectrometry (MS) assay to determine the relative activities, kinetics, and cell-type specificity of thalidomide and 4 analogs, all but 1 of which are in clinical use or clinical trials for hematologic malignancies. Thalidomide analogs bind the CRL4CRBN ubiquitin ligase and induce degradation of particular proteins, but each of the molecules studied has distinct patterns of substrate specificity that likely underlie the clinical activity and toxicities of each drug. Our results demonstrate that the activity of molecules that induce protein degradation depends on the strength of ligase-substrate interaction in the presence of drug, the levels of the ubiquitin ligase, and the expression level of competing substrates. These findings highlight a novel mechanism of resistance to this class of drugs mediated by competition between substrates for access to a limiting pool of the ubiquitin ligase. We demonstrate that increased expression of a nonessential substrate can lead to decreased degradation of other substrates that are critical for antineoplastic activity of the drug, resulting in drug resistance. These studies provide general rules that govern drug-dependent substrate degradation and key differences between thalidomide analog activity in vitro and in vivo.
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Affiliation(s)
- Adam S Sperling
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | | | | | - Jessica A Gasser
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Shruti Bhatt
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Max Jan
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Mikołaj Słabicki
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
- Division of Translational Oncology, National Center for Tumor Diseases Heidelberg, German Cancer Research Center, Heidelberg, Germany; and
| | - Rob S Sellar
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
- Department of Haematology, UCL Cancer Institute, University College London, London, United Kingdom
| | - Emma C Fink
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Peter G Miller
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Brian J Liddicoat
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Quinlan L Sievers
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Rohan Sharma
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
| | - Dylan N Adams
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
| | - Elyse A Olesinski
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | | | | | - Eric Kuhn
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Anthony Letai
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Nikhil C Munshi
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | | | - Benjamin L Ebert
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
- Division of Hematology, Brigham and Women's Hospital, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
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8
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Sievers QL, Gasser JA, Cowley GS, Fischer ES, Ebert BL. Genome-wide screen identifies cullin-RING ligase machinery required for lenalidomide-dependent CRL4 CRBN activity. Blood 2018; 132:1293-1303. [PMID: 30042095 PMCID: PMC6148446 DOI: 10.1182/blood-2018-01-821769] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 07/02/2018] [Indexed: 12/20/2022] Open
Abstract
Lenalidomide mediates the ubiquitination and degradation of Ikaros family zinc finger protein 1 (IKZF1), IKZF3, and casein kinase 1α (CK1α) by facilitating their interaction with cereblon (CRBN), the substrate receptor for the CRL4CRBN E3 ubiquitin ligase. Through this mechanism, lenalidomide is a clinically effective treatment of multiple myeloma and myelodysplastic syndrome (MDS) with deletion of chromosome 5q [del(5q) MDS]. To identify the cellular machinery required for lenalidomide-induced CRL4CRBN activity, we performed a positive selection, genome-scale clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) screen in a lenalidomide-sensitive myeloma cell line. CRBN was the top-ranking gene, with all CRBN-targeting guide RNAs (gRNAs) ranking as the 6 highest-scoring gRNAs. A counterscreen using an IKZF3 degron reporter to assay lenalidomide-induced protein degradation highlighted regulators of cullin-RING ligase neddylation and 2 E2 ubiquitin-conjugating enzymes as necessary for efficient lenalidomide-induced protein degradation. We demonstrated that loss of UBE2M or members of the constitutive photomorphogenesis 9 (COP9) signalosome results in altered neddylation of cullin 4A and impairs lenalidomide-dependent CRL4CRBN activity. Additionally, we established that UBE2D3 and UBE2G1 play distinct roles in substrate ubiquitination by CRL4CRBN, with UBE2D3 acting to prime targets via monoubiquitination and UBE2G1 functioning to extend polyubiquitin chains with lysine 48 linkages. The validation of UBE2D3 and UBE2G1 highlights the functional capacity of CRISPR-Cas9 screening to identify E2 ubiquitin-conjugating enzyme and E3 ubiquitin ligase complex pairings. More broadly, these findings establish key proteins required for lenalidomide-dependent CRL4CRBN function in myeloma and inform potential mechanisms of drug resistance.
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Affiliation(s)
- Quinlan L Sievers
- Broad Institute of MIT and Harvard, Cambridge, MA
- Division of Hematology, Brigham and Women's Hospital, and
- MD/PhD Program, Harvard Medical School, Boston, MA
| | - Jessica A Gasser
- Broad Institute of MIT and Harvard, Cambridge, MA
- Division of Hematology, Brigham and Women's Hospital, and
| | | | - Eric S Fischer
- Department of Chemical Biology, Dana-Farber Cancer Institute, Boston, MA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA; and
| | - Benjamin L Ebert
- Broad Institute of MIT and Harvard, Cambridge, MA
- Division of Hematology, Brigham and Women's Hospital, and
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
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9
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Abstract
PTH is indicated for the treatment of severe osteoporosis. Elderly osteoporotic patients frequently suffer from protein malnutrition, which may contribute to bone loss. It is unknown whether this malnutrition may affect the response to PTH. Therefore, the aim of the present study was to assess whether an isocaloric low-protein (LP) diet may influence the bone anabolic response to intermittent PTH in 6-month-old female rats. Six-month-old female rats were either pair fed an isocaloric LP diet (2.5% casein) or a normal-protein (NP) diet (15% casein) for 2 weeks. The rats continued on their respective diet while being treated with 5- or 40-μg/kg recombinant human PTH amino-terminal fragment 1-34 (PTH-[1-34]) daily, or with vehicle for 4 weeks. At the end of this period, areal bone mineral density, bone mineral content, microstructure, and bone strength in axial compression of proximal tibia or 3-point bending for midshaft tibia tests were measured. Blood was collected for the determination of IGF-I and osteocalcin. After 4 weeks of PTH-(1-34), the dose-dependent increase of proximal tibia bone mineral density, trabecular microstructure variables, and bone strength was attenuated in rats fed a LP diet as compared with rats on a NP intake. At the level of midshaft tibia cortical bone, PTH-(1-34) exerted an anabolic effect only in the NP but not in the LP diet group. Protein malnutrition was associated with lower IGF-I levels. Protein malnutrition attenuates the bone anabolic effects of PTH-(1-34) in rats. These results suggest that a sufficient protein intake should be recommended for osteoporotic patients undergoing PTH therapy.
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Affiliation(s)
- P Ammann
- Division of Bone Disease (P.A., G.Z., C.L., R.R.), Department of Internal Medicine Specialties, Geneva University Hospitals and Faculty of Medicine, CH 1211 Geneva, Switzerland; and Novartis Institutes for BioMedical Research (J.A.G.), CH 4001 Basel, Switzerland
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10
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Gasser JA, Inuzuka H, Lau AW, Wei W, Beroukhim R, Toker A. SGK3 mediates INPP4B-dependent PI3K signaling in breast cancer. Mol Cell 2014; 56:595-607. [PMID: 25458846 DOI: 10.1016/j.molcel.2014.09.023] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 08/15/2014] [Accepted: 09/25/2014] [Indexed: 11/26/2022]
Abstract
Oncogenic mutations in PIK3CA, the gene encoding the catalytic subunit of phosphoinositide 3-kinase (PI3K), occur with high frequency in breast cancer. The protein kinase Akt is considered to be the primary effector of PIK3CA, although mechanisms by which PI3K mediates Akt-independent tumorigenic signals remain obscure. We show that serum and glucocorticoid-regulated kinase 3 (SGK3) is amplified in breast cancer and activated downstream of PIK3CA in a manner dependent on the phosphoinositide phosphatase INPP4B. Expression of INPP4B leads to enhanced SGK3 activation and suppression of Akt phosphorylation. Activation of SGK3 downstream of PIK3CA and INPP4B is required for 3D proliferation, invasive migration, and tumorigenesis in vivo. We further show that SGK3 targets the metastasis suppressor NDRG1 for degradation by Fbw7. We propose a model in which breast cancers harboring oncogenic PIK3CA activate SGK3 signaling while suppressing Akt, indicative of oncogenic functions for both INPP4B and SGK3 in these tumors.
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Affiliation(s)
- Jessica A Gasser
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Alan W Lau
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Rameen Beroukhim
- Cancer Program and Medical and Population Genetics Group, The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Departments of Medical Oncology, Pediatric Oncology, and Cancer Biology and Center for Cancer Genome Discovery, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Departments of Medicine and Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA; Departments of Medicine, Pathology, Pediatrics, and Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Alex Toker
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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11
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Gamsjaeger S, Hofstetter B, Zwettler E, Recker R, Gasser JA, Eriksen EF, Klaushofer K, Paschalis EP. Effects of 3 years treatment with once-yearly zoledronic acid on the kinetics of bone matrix maturation in osteoporotic patients. Osteoporos Int 2013; 24:339-47. [PMID: 23229465 DOI: 10.1007/s00198-012-2202-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [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: 03/12/2012] [Accepted: 09/26/2012] [Indexed: 11/29/2022]
Abstract
UNLABELLED Once-yearly administration of intravenous zoledronic acid for 3 years in humans affects the kinetics of matrix filling in by mineral, independent of bone turnover. INTRODUCTION Yearly 5-mg infusions of zoledronic acid (ZOL) for 3 years have shown pronounced antifracture efficacy. The purpose of the present study was to test whether ZOL affects the kinetics of forming bone material properties maturation. METHODS Iliac crest biopsies from the HORIZON-PFT clinical trial were analyzed by Raman microspectroscopy in actively bone-forming surfaces as a function of tissue age in trabecular and osteonal bone, to determine ZOL's effect on bone material quality indices maturation kinetics. RESULTS Mineral/matrix ratio increased in both groups as a function of tissue age, at both osteonal- and trabecular-forming surfaces; ZOL exhibiting the greatest increase in the trabecular surfaces only. The proteoglycan content showed a dependency on tissue age in both trabecular and osteonal surfaces, with ZOL exhibiting lower values in the tissue age 8-22 days in the trabecular surfaces. Mineral crystallinity (crystallite length and thickness) showed a dependence on tissue age, with ZOL exhibiting lower crystallite length compared with placebo only in the 8- to 22-day-old tissue at trabecular surfaces, while crystal thickness was lower in the 1- to 5-day-old tissue at both osteonal and trabecular surfaces. CONCLUSIONS The results of the present study suggest that once-yearly administration of intravenous ZOL for 3 years in humans does not exert any adverse effects on the evolution of bone material properties at actively forming osteonal and trabecular surfaces, while it may have a beneficial effect on the progression of the mineral-to-matrix ratio and mineral maturity bone quality indices.
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Affiliation(s)
- S Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria.
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12
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Gao D, Wan L, Inuzuka H, Berg AH, Tseng A, Zhai B, Shaik S, Bennett E, Tron AE, Gasser JA, Lau A, Gygi SP, Harper JW, DeCaprio JA, Toker A, Wei W. Rictor forms a complex with Cullin-1 to promote SGK1 ubiquitination and destruction. Mol Cell 2010; 39:797-808. [PMID: 20832730 DOI: 10.1016/j.molcel.2010.08.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 03/24/2010] [Accepted: 06/21/2010] [Indexed: 12/31/2022]
Abstract
The Rictor/mTOR complex (also known as mTORC2) plays a critical role in cellular homeostasis by phosphorylating AGC kinases such as Akt and SGK at their hydrophobic motifs to activate downstream signaling. However, the regulation of mTORC2 and whether it has additional function(s) remain largely unknown. Here, we report that Rictor associates with Cullin-1 to form a functional E3 ubiquitin ligase. Rictor, but not Raptor or mTOR alone, promotes SGK1 ubiquitination. Loss of Rictor/Cullin-1-mediated ubiquitination leads to increased SGK1 protein levels as detected in Rictor null cells. Moreover, as part of a feedback mechanism, phosphorylation of Rictor at T1135 by multiple AGC kinases disrupts the interaction between Rictor and Cullin-1 to impair SGK1 ubiquitination. These findings indicate that the Rictor/Cullin-1 E3 ligase activity is regulated by a specific signal relay cascade and that misregulation of this mechanism may contribute to the frequent overexpression of SGK1 in various human cancers.
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Affiliation(s)
- Daming Gao
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
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13
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Gasser JA. Knochenstoffwechsel im Kindesalter. ROFO-FORTSCHR RONTG 2008. [DOI: 10.1055/s-2008-1073253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Gasser JA. Coupled or uncoupled remodeling, is that the question? J Musculoskelet Neuronal Interact 2006; 6:128-33. [PMID: 16849821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Affiliation(s)
- J A Gasser
- Novartis Institutes for Biomedical Research, Basel, Switzerland.
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15
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Gerharz EW, Mosekilde L, Thomsen JS, Gasser JA, Moniz C, Barth PJ, Ransley PG, Woodhouse CRJ. The effect of enterocystoplasty on bone strength assessed at four different skeletal sites in a rat model. Bone 2003; 33:549-56. [PMID: 14555258 DOI: 10.1016/s8756-3282(03)00247-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The objective of the study was to investigate bone strength at four different skeletal sites in a chronic animal model of urinary diversion. Young male Wistar rats (120) were allocated randomly to four groups undergoing ileocystoplasty; ileocystoplasty and resection of the ileocecal segment; colocystoplasty; or sham operation (controls). After 8 months the lumbar vertebrae, femora, and tibiae were harvested at necropsy. Bone strength was assessed biomechanically at four different skeletal sites: vertebra L3, femoral middiaphysis, femoral neck, and distal femoral metaphysis. Bone mass and architecture were assessed using standard static histomorphometry of the proximal tibial metaphysis (trabecular bone volume [BV/TV]; trabecular number [Tb.N]) and ash weight. Statistically significant differences of biomechanical parameters between groups were observed at three skeletal sites with corresponding changes in tibial histomorphometry. Isolated ileocystoplasty resulted in decreased maximum load values of L3 (-16.4%; p < 0.0035) and a substantial reduction in tibial BV/TV (-34.7%; p < 0.05). Ileocystoplasty combined with resection of the ileocecal segment led to a significant loss of bone strength of L3 (-32.4%; p < 0.0015) and a dramatic reduction of tibial BV/TV (-45.9%; p < 0.01). Loss of tibial metaphyseal bone mass was predominantly caused by a decrease in Tb.N. (p < 0.01). Colonic augmentation had no significant effect on bone strength or histomorphometric values. In conclusion, this is the first experimental study to demonstrate the relevance of histomorphometrically proven bone loss after enterocystoplasty in terms of biomechanical variables.
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Affiliation(s)
- E W Gerharz
- Institute of Urology and Nephrology, Royal Free and University College London Medical School, London, UK.
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16
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Gerharz EW, Gasser JA, Mosekilde L, Moniz C, Sitter H, Barth PJ, Thomsen JS, Ransley PG, Riedmiller H, Woodhouse CRJ. Skeletal growth and long-term bone turnover after enterocystoplasty in a chronic rat model. BJU Int 2003; 92:306-13. [PMID: 12887489 DOI: 10.1046/j.1464-410x.2003.04327.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [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: 11/20/2022]
Abstract
OBJECTIVE To investigate skeletal growth and bone metabolism in a chronic animal model of urinary diversion. MATERIALS AND METHODS Young male Wistar rats (120) were allocated randomly to four groups undergoing: ileocystoplasty, ileocystoplasty and resection of the ileocaecal segment, colocystoplasty, and controls. All animals received antibiotics for 1 week after surgery; half of each group remained on oral antibiotics. Bone-related biochemistry was measured in serum and urine. Dual-energy X-ray absorptiometry and peripheral quantitative computed tomography (pQCT) were used to determine bone mass ex vivo. RESULTS Most (90%) of the rats survived the study period (8 months); six rats died from bowel obstruction at the level of the entero-anastomosis and four had to be killed because of persistent severe diarrhoea. Vital intestinal mucosa was found in all augmented bladders. There were no differences in bone length and volume. Loss of bone mass was almost exclusively in rats with ileocystoplasty and resection of the ileocaecal segment (-37.5%, pQCT, P < 0.01). There was no hyperchloraemic metabolic acidosis or gross impairment of renal function. Hypomagnesaemia, hypocalcaemia and decreased insulin-like growth factor-binding protein 3 were the only significant findings on blood analysis. Deoxypyridinoline crosslinks in urine were higher in rats with an enterocystoplasty than in controls. CONCLUSIONS Enterocystoplasty in rats neither impairs skeletal growth nor bone quantity, but leads to significant loss of bone mass when combined with resection of the ileocaecal segment. Rarefaction of the trabecular network is confined to the metabolically highly active cancellous compartment, most likely as a consequence of intestinal malabsorption.
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Affiliation(s)
- E W Gerharz
- The Institute of Urology & Nephrology, Royal Free and University College London Medical School, London, UK.
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17
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Steiner PD, Forrer R, Kneissel M, Gasser JA, Thomsen JS, Mosekilde L, Riond JL. Influence of a low calcium and phosphorus diet on the anabolic effect of human parathyroid hormone (1-38) in female rats. Bone 2001; 29:344-51. [PMID: 11595617 DOI: 10.1016/s8756-3282(01)00506-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Parathyroid hormone (PTH) or synthetic N-terminal PTH fragments administered intermittently have been established as anabolic agents in animal and human bones. In the present study, the influence of a low calcium diet on the anabolic effect of human PTH(1-38) [hPTH(1-38)] was investigated. Forty-eight 10-week-old female Sprague-Dawley rats were randomly assigned to a diet with a low calcium content (LCa) or a diet with the recommended amount of calcium (RCa). After an adaptation period of 15 days, the rats were randomly assigned to hPTH(1-38) treatment (+LCa/+RCa) or vehicle only (-LCa/-RCa) for an additional 14 days. Total bone mineral density (BMD) values of several bones were determined using quantitative computed tomography and from ratios of ash weight to volume. Biomechanical competence of the fourth lumbar vertebrae and of the right femora was assessed. An anabolic effect could be detected in both PTH-treated groups. However, the bones of the +LCa group showed significantly lower BMD and also a diminished increase in maximal breaking force compared with those of the +RCa group. The study demonstrates that the anabolic effect of hPTH(1-38) is blunted by the LCa diet. This suggests that, during PTH treatment, dietary calcium intake is critical.
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Affiliation(s)
- P D Steiner
- Institute of Animal Nutrition, Department of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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18
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Halleux C, Sottile V, Gasser JA, Seuwen K. Multi-lineage potential of human mesenchymal stem cells following clonal expansion. J Musculoskelet Neuronal Interact 2001; 2:71-6. [PMID: 15758478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Bone marrow contains mesenchymal cells that can be isolated and grown in vitro. Using appropriate treatment protocols such cultures can be induced to differentiate to yield osteoblasts, adipocytes, and chondrocytes. However, previous experiments had not addressed the question whether single pluripotent stem cells exist and can give rise to these different cell lineages or whether bone marrow mesenchymal cell preparations represent a mixture of committed precursors. We have used human adult bone marrow-derived mesenchymal cells obtained from iliac crest biopsies to demonstrate clonal outgrowth after limiting dilution and we show that some clones can be expanded over more than 20 cumulative population doublings and differentiated to osteoblasts, adipocytes, and chondrocytes. Our data provide direct experimental evidence that cultures of bone marrow-derived mesenchymal cells contain individual cells that fulfil two essential stem cell criteria: (i) extensive self-renewal capacity and (ii) multi-lineage potential.
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Affiliation(s)
- C Halleux
- Research, Novartis Pharma AG, Basel, Switzerland
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Gasser JA. Bone anabolic agents. Introduction. J Musculoskelet Neuronal Interact 2001; 2:1-2. [PMID: 15758470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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Kneissel M, Boyde A, Gasser JA. Bone tissue and its mineralization in aged estrogen-depleted rats after long-term intermittent treatment with parathyroid hormone (PTH) analog SDZ PTS 893 or human PTH(1-34). Bone 2001; 28:237-50. [PMID: 11248653 DOI: 10.1016/s8756-3282(00)00448-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Intermittently administered parathyroid hormone (PTH) is a potent bone anabolic agent. We aimed to determine the impact of long-term treatment with PTH on bone structure, dynamics, and mineralization. We ovariectomized (ovx) 1-year-old rats with the exception of a baseline and a sham-operated group. Twelve weeks later, a 36 week treatment with PTH analog SDZ PTS 893 (12.5, 25, 50, 100 microg/kg), human PTH(1-34) (25, 50, 100 microg/kg), or vehicle (ovx, sham) was initiated. Bone dynamics, structure, and mineralization were evaluated in the lumbar spine and in the femoral diaphysis. Cancellous bone turnover was elevated 12 weeks postovariectomy in estrogen-deficient, vehicle-treated animals, but returned to the level of the sham group by 48 weeks. The animals experienced substantial cancellous bone loss associated with a reduction of trabecular number and presented with a partly rod-like trabecular network. After 36 weeks of treatment with SDZ PTS 893 or human PTH(1-34), cancellous bone formation rates and turnover were raised in all treated groups compared with age-matched controls. The mineral apposition rate was increasing with dose. This amplified matrix synthesis led to trabecular thickening, but not to an increase in trabecular number, resulting in a crude, plate-like cancellous network with a high bone volume fraction. Fluorochrome label-based cortical bone dynamics demonstrated that a thick ring of new bone was formed at the endocortex by activation of modeling drifts during treatment. Treatment-induced cortical bone formation was increased with dose at the subperiosteal and endocortical envelopes, but substantially higher at the latter. Intracortical bone turnover was elevated near the endocortex. Bone mineralization was undisturbed in all compartments. The average degree of mineralization was lowered slightly, reflecting the increased portion of new bone formed during treatment. In summary, the main anabolic effect was mediated for both peptides by an increase in bone apposition with dose, persisting throughout treatment that lasted more than one third of the lifespan of the rats, and direct activation of bone-forming surfaces. As a result, a substantial amount of new bone, maintained at elevated turnover and adequate mineralization levels, formed predominantly at compartments exposed to bone marrow.
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Affiliation(s)
- M Kneissel
- Bone Metabolism Unit, Therapeutic Area of Arthritis and Bone Metabolism, Novartis Pharma AG, Basel, Switzerland.
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Cornish J, Callon KE, Gasser JA, Bava U, Gardiner EM, Coy DH, Cooper GJ, Reid IR. Systemic administration of a novel octapeptide, amylin-(1---8), increases bone volume in male mice. Am J Physiol Endocrinol Metab 2000; 279:E730-5. [PMID: 11001752 DOI: 10.1152/ajpendo.2000.279.4.e730] [Citation(s) in RCA: 25] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amylin increases bone mass when administered systemically to mice. However, because of its size, the full peptide is not an ideal candidate for the therapy of osteoporosis. The fragment, amylin-(1---8), stimulates osteoblast proliferation in vitro, although it is without effect on carbohydrate metabolism. The present study assessed the effects of daily administration of this peptide on sexually mature male mice for 4 wk. Amylin-(1---8) almost doubled histomorphometric indices of osteoblast activity but did not change measures of bone resorption. Trabecular bone volume increased by 36% as a result of increases in both trabecular number and trabecular thickness, and tibial cortical width increased by 8%. On three-point bending tests of bone strength, displacement to fracture was increased by amylin-(1---8), from 0.302 +/- 0.013 to 0.351 +/- 0. 017 mm (P = 0.02). In a separate experiment using dynamic histomorphometry with bone-seeking fluorochrome labels, amylin-(1---8) was administered by local injection over the calvariae of female mice. Amylin-(1---8) (40 nM) increased the double-labeled surface threefold. The effect was dose dependent from 0.4 to 40 nM and was greater than that of an equimolar dose of human parathyroid hormone-(1---34) [hPTH-(1---34)]. Mineral apposition rate was increased by 40 nM amylin-(1---8) but not by hPTH-(1---34). Amylin-(1---8) thus has significant anabolic effects in vivo, suggesting that this peptide or analogs of it should be further evaluated as potential therapies for osteoporosis.
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Affiliation(s)
- J Cornish
- Department of Medicine, University of Auckland, Auckland 1001, New Zealand.
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Gasser JA, Kneissel M, Thomsen JS, Mosekilde L. PTH and interactions with bisphosphonates. J Musculoskelet Neuronal Interact 2000; 1:53-6. [PMID: 15758526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We report that a therapeutic dose of the antiresorptive bisphosphonate alendronate administered to skeletally mature rats for the duration of 16 weeks significantly blunted the anabolic response to a high dose SDZ PTS 893 in the tibia and femur but not in lumbar vertebra. Effects were seen at the level of bone mass (DEXA, pQCT) as well as in biomechanical tests. In one arm of this study, rats were switched to vehicle injections after 8 weeks on alendronate for another 8 weeks before being challenged with the anabolic stimulus (washout). This recovery period was insufficient for full recovery and the response to SDZ PTS 893 was still greatly reduced after this procedure. Serial pQCT-measurements suggest that part of the interaction happened during the first two weeks of PTH treatment when bone-lining cells are activated by the anabolic drug. In addition bisphosphonate pretreated rats failed to catch up with the vehicle control at all time points suggesting a second level of drug interaction. The failure of the 'washout' period to restore the normal response to PTH is suggestive of a physico-chemical interaction on the level of the matrix embedded bisphosphonate with the overlaying bone lining cells, rather than of direct effects of the drug on osteoblasts or their precursor cells. Overall the data raises the possibility, that bisphosphonate treated patients respond to PTH and SDZ PTS 893 with a delay which could affect the shorter bone mass measurements carried out at 6 months to 1 year. Additionally, bisphosphonate pre-treated rats did not develop the full anabolic response over time. Clinical investigators studying anabolic drugs such as PTH should be aware of potential long-term interactions of bisphosphonates when assessing the outcome of their experiments. However, the beneficial effect of bisphosphonates like alendronate on PTH-induced bone remodeling, as well as its potent action in the protection of bone loss after cessation of anabolic therapy might outweigh the worries about a small delay in the bone response to parathyroid hormone.
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Thomsen JS, Mosekilde LI, Gasser JA. Long-term therapy of ovariectomy-induced osteopenia with parathyroid hormone analog SDZ PTS 893 and bone maintenance in retired breeder rats. Bone 1999; 25:561-9. [PMID: 10574576 DOI: 10.1016/s8756-3282(99)00212-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of the study was to assess the long-term anabolic effect of the parathyroid hormone (PTH) analog SDZ PTS 893 in a dose-response manner, and to determine the ability of the antiresorptive agents estradiol and alendronate to maintain bone mass after withdrawal of SDZ PTS 893. One hundred thirty retired breeder Wistar rats were distributed into 13 groups with 10 rats in each group: 1 baseline group, 2 sham groups, and 10 ovariectomized groups. Treatment was initiated 12 weeks after ovariectomy. SDZ PTS 893 treatment was administered daily subcutaneously (Monday to Friday) for 36 weeks. Treatment regimens were as follows: (1) baseline (-12 weeks); (2) ovariectomy (ovx) (0 weeks); (3) sham (36 weeks); (4) ovx (36 weeks); (5) SDZ PTS 893 12.5 microg/kg/day (36 weeks); (6) SDZ PTS 893 25 microg/kg/day (36 weeks); (7) SDZ PTS 893 50 microg/kg/day (36 weeks); (8) SDZ PTS 893 100 microg/kg/day (36 weeks); for the maintenance part of the study: (9) sham (48 weeks); ovx animals treated with SDZ PTS 893, 50 microg/kg/day for 36 weeks followed by 12 weeks of treatment regimens: (10) placebo; (11) SDZ PTS 893 50 microg/kg/day; (12) estradiol 10 microg/kg/day; or (13) alendronate 28 microg/kg (2 injections/week). The effects of ovx, SDZ PTS 893 treatment, and maintenance regimens were measured at four skeletal sites: lumbar vertebra; femoral diaphysis; distal femoral metaphysis; and proximal femoral metaphysis (femoral neck). At these sites, bone density and bone strength were measured as treatment endpoints. Furthermore, bone dimensions were measured at the midpoint of the femur. The results showed that SDZ PTS 893 increased bone strength in a dose-dependent manner at all skeletal sites tested. At the vertebral body and distal femoral metaphysis, apparent ash density increased in a similar way. There was a slight decrease in cortical density at the mid-diaphyseal site. Static histomorphometry showed increased bone area due to a decreased marrow area (endosteal net bone gain) but also due to increased tissue area (periosteal net bone gain). For maintenance, continuous SDZ PTS 893 therapy was most efficient, followed by alendronate and estradiol treatment with regard to preservation of bone mass and strength. It is concluded that the new PTH analog SDZ PTS 893 has a highly anabolic, dose- and time-dependent effect on all skeletal sites tested. Bone formation is induced at both endosteal and periosteal surfaces.
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Affiliation(s)
- J S Thomsen
- Department of Cell Biology, Institute of Anatomy, University of Aarhus, Denmark
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Ferretti JL, Frost HM, Gasser JA, High WB, Jee WS, Jerome C, Mosekilde L, Thompson DD. Perspectives on osteoporosis research: its focus and some insights from a new paradigm. Calcif Tissue Int 1995; 57:399-404. [PMID: 8581868 DOI: 10.1007/bf00301939] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Abstract
We have tested the ability of the XCT960A to detect bone loss in OVX-rats, as well as bone gain in the proximal tibial metaphysis of healthy rats treated with hPTH(1-34). The results demonstrated that high precision can be achieved, with CV's for most measurement parameters in the range of 1.6 to 5.9% being obtained in vivo with repositioning of animals. Significant changes in bone parameters in the tibia were observed already at 2 weeks following OVX or PTH-therapy, while whole bone mass measured in the tibia by DEXA ex vivo did not change significantly for up to 24 weeks. For the proximal rat tibia at location 5mm distal to the knee joint was identified as an optimal site. At this location, cortices are fairly parallel thus reducing the partial volume effect, the area is relatively rich in cancellous bone increasing the magnitude of bone gain or loss, and the site (2mm below the growth plate) is relevant for comparisons with histomorphometric measurements. The results demonstrate that pQCT can be adapted for use in small animals such as rats, and that it is a sensitive, reproducible, non-invasive method available to monitor changes in bone mass, bone density, and geometric properties. Future studies should help to establish whether the moment of inertia, moment of resistance and the newly added bone strength index provided by the machine are predictive in any way for bone strength as obtained from biomechanical testing procedures. Peripheral QCT in small animals is an important addition for drug evaluation because it is more sensitive than DEXA and allows for shorter duration of experiments. This non-invasive method can reliably measure changes in cancellous and cortical bone mass over time following ovariectomy or administration of the bone anabolic hormone hPTH(1-34). pQCT should be viewed as a complimentary technique to static and dynamic histomorphometry, which does not replace either of these methods. Its value in the field of basic research should be evaluated.
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Gasser JA, Cooper MB, Tan KC, Saggerson ED, Betteridge DJ. Decreased sensitivity to adenosine in platelets from patients with familial hypercholesterolaemia--a change reversed by cholestyramine treatment. Eur J Clin Invest 1993; 23:803-11. [PMID: 8143757 DOI: 10.1111/j.1365-2362.1993.tb00734.x] [Citation(s) in RCA: 4] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Platelet-rich plasma was obtained from patients with untreated heterozygous familial hypercholesterolaemia (FH), from FH patients treated with cholestyramine and from control subjects. Responsiveness of platelets to the aggregation inhibitors adenosine, its analogue N-ethylcarboxamidoadenosine (NECA) and prostaglandin I2 was decreased in FH. Patients on cholestyramine therapy showed normal responsiveness to adenosine and NECA. There were only minor changes in the binding of [3H]NECA to high-affinity binding sites on platelet membranes from untreated FH or cholestyramine-treated FH patients. The initial rate of cyclic AMP formation in response to a high concentration of NECA was severely decreased in platelets from FH patients. By contrast, the rate of cyclic AMP formation in response to forskolin or a high concentration of prostaglandin I2 was unchanged. These data point to a defect in the coupling of the platelet A2 adenosine receptor to adenylyl cyclase in untreated FH patients.
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Affiliation(s)
- J A Gasser
- Department of Medicine, University College London Medical School, Sir Jules Thorn Institute, Middlesex Hospital, UK
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Gasser JA, Cooper MB, Tan KC, Saggerson ED, Betteridge DJ. Altered cellular signalling and decreased platelet sensitivity to adenosine in insulin-dependent diabetic patients with proliferative retinopathy. Cell Signal 1993; 5:145-53. [PMID: 8499224 DOI: 10.1016/0898-6568(93)90066-u] [Citation(s) in RCA: 12] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Platelets from patients with insulin-dependent diabetes with proliferative retinopathy showed the same reactivity to ADP as those from control subjects. Responsiveness of platelets to the aggregation inhibitor adenosine and to the analogue N-ethylcarboxamidoadenosine was decreased in diabetes. In contrast, responsiveness to the anti-aggregatory effects of prostaglandin I2 was not significantly altered in diabetes. Platelets from diabetic patients exhibited decreased formation of cyclic AMP in response to N-ethylcarboxamidoadenosine compared with those from control subjects. In contrast, when adenylyl cyclase was stimulated by prostaglandin I2 or by forskolin, no differences in cyclic AMP formation were observed between control and diabetic platelets. Diabetes was associated with an apparent loss of high-affinity binding of [3H]N-ethylcarboxamidoadenosine to platelet membranes. Possible mechanisms that could contribute to this diabetes-induced change in signalling through the platelet A2 adenosine receptor are discussed.
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Affiliation(s)
- J A Gasser
- Department of Medicine, University College and Middlesex School of Medicine, Sir Jules Thorn Institute, Middlesex Hospital, London, U.K
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Abstract
There is extensive evidence of important interactions between plasma lipoproteins and platelet function. Some population groups, particularly hypercholesterolaemic patients, have strong evidence of abnormal platelet function which is mediated by the binding of lipoproteins, especially oxidized LDL, to surface receptors. Additionally, abnormal plasma lipid levels precipitate membrane composition changes by increasing the cholesterol:phospholipid ratio. The resulting changes in microviscosity seem to affect transmembrane signalling and might in some cases influence receptor binding. This not only has important therapeutic implications with regard to lipid-lowering drug therapy but also with regard to the potential beneficial effects of dietary therapy.
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Maletta JA, Gasser JA, Fonseca RJ, Nelson JA. Comparison of the healing and revascularization of onlayed autologous and lyophilized allogeneic rib grafts to the edentulous maxilla. J Oral Maxillofac Surg 1983; 41:487-99. [PMID: 6191016 DOI: 10.1016/0278-2391(83)90239-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The healing and revascularization of onlayed autologous and lyophilized allogeneic rib grafts to the edentulous maxilla in the Macaca fascicularis monkey were studied using clinical, histologic, and microangiographic methods at varying intervals of up to eight months. Results indicated that healing and revascularization were similar but resorption of the allografts occurred approximately three months later than resorption of the autografts. Both grafting systems appeared to have minimal osteogenic potential. Osteoinduction and the final bony augmentation obtained were less than were seen with comparable autologous and allogeneic interpositional grafts.
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