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Dai J, Cimino PJ, Gouin KH, Grzelak CA, Barrett A, Lim AR, Long A, Weaver S, Saldin LT, Uzamere A, Schulte V, Clegg N, Pisarsky L, Lyden D, Bissell MJ, Knott S, Welm AL, Bielas JH, Hansen KC, Winkler F, Holland EC, Ghajar CM. Astrocytic laminin-211 drives disseminated breast tumor cell dormancy in brain. Nat Cancer 2022; 3:25-42. [PMID: 35121993 PMCID: PMC9469899 DOI: 10.1038/s43018-021-00297-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/27/2021] [Indexed: 02/08/2023]
Abstract
Although dormancy is thought to play a key role in the metastasis of breast tumor cells to the brain, our knowledge of the molecular mechanisms regulating disseminated tumor cell (DTC) dormancy in this organ is limited. Here using serial intravital imaging of dormant and metastatic triple-negative breast cancer lines, we identify escape from the single-cell or micrometastatic state as the rate-limiting step towards brain metastasis. We show that every DTC occupies a vascular niche, with quiescent DTCs residing on astrocyte endfeet. At these sites, astrocyte-deposited laminin-211 drives DTC quiescence by inducing the dystroglycan receptor to associate with yes-associated protein, thereby sequestering it from the nucleus and preventing its prometastatic functions. These findings identify a brain-specific mechanism of DTC dormancy and highlight the need for a more thorough understanding of tumor dormancy to develop therapeutic approaches that prevent brain metastasis.
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Affiliation(s)
- Jinxiang Dai
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
| | - Patrick J. Cimino
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA (USA)
| | - Kenneth H. Gouin
- Department of Biomedical Sciences; Applied Genomics, Computation and Translational Core, Cedars-Sinai Medical Center, Los Angeles, CA (USA)
| | - Candice A. Grzelak
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Alexander Barrett
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO (USA)
| | - Andrea R. Lim
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA),Graduate Program in Molecular and Cellular Biology, University of Washington, Seattle, WA (USA)
| | - Annalyssa Long
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Stephanie Weaver
- Experimental Histopathology Core, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Lindsey T. Saldin
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA (USA)
| | - Aiyedun Uzamere
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Vera Schulte
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Nigel Clegg
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Laura Pisarsky
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - David Lyden
- Children’s Cancer and Blood Foundation Laboratories, Departments of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children’s Health, Meyer Cancer Center, Weill Cornell Medicine, New York, NY, (USA)
| | - Mina J. Bissell
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA (USA)
| | - Simon Knott
- Department of Biomedical Sciences; Applied Genomics, Computation and Translational Core, Cedars-Sinai Medical Center, Los Angeles, CA (USA)
| | - Alana L. Welm
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT (USA)
| | - Jason H. Bielas
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA),Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA (USA),Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Kirk C. Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO (USA)
| | - Frank Winkler
- Neurology Clinic and National Center for Tumour Diseases, University Hospital Heidelberg, DKTK & Clinical Cooperation Unit Neurooncology, German Cancer Research Center, Heidelberg (Germany)
| | - Eric C. Holland
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA (USA)
| | - Cyrus M. Ghajar
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA (USA),Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA (USA),To whom correspondence should be addressed: Cyrus M. Ghajar, PhD, Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., M5-A864, Seattle, WA 98109 (USA), , P. 206.667.7080, F. 206.667.2537, Jinxiang Dai, PhD, Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N., M5-A864, Seattle, WA 98109 (USA), , P. 206.667.7082, F. 206.667.2537
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Shor RE, Dai J, Lee SY, Pisarsky L, Matei I, Lucotti S, Lyden D, Bissell MJ, Ghajar CM. The PI3K/mTOR inhibitor Gedatolisib eliminates dormant breast cancer cells in organotypic culture, but fails to prevent metastasis in preclinical settings. Mol Oncol 2021; 16:130-147. [PMID: 34058066 PMCID: PMC8732345 DOI: 10.1002/1878-0261.13031] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/31/2021] [Accepted: 05/28/2021] [Indexed: 02/06/2023] Open
Abstract
Dormant, disseminated tumor cells (DTCs) are thought to be the source of breast cancer metastases several years or even decades after initial treatment. To date, a selective therapy that leads to their elimination has not been discovered. While dormant DTCs resist chemotherapy, evidence suggests that this resistance is driven not by their lack of proliferation, but by their engagement of the surrounding microenvironment, via integrin‐β1‐mediated interactions. Because integrin‐β1‐targeted agents have not been translated readily to the clinic, signaling nodes downstream of integrin‐β1 could serve as attractive therapeutic targets in order to sensitize dormant DTCs to therapy. By probing a number of kinases downstream of integrin‐β1, we determined that PI3K inhibition with either a tool compounds or a compound (PF‐05212384; aka Gedatolisib) in clinical trials robustly sensitizes quiescent breast tumor cells seeded in organotypic bone marrow cultures to chemotherapy. These results motivated the preclinical study of whether Gedatolisib—with or without genotoxic therapy—would reduce DTC burden and prevent metastases. Despite promising results in organotypic culture, Gedatolisib failed to reduce DTC burden or delay, reduce or prevent metastasis in murine models of either triple‐negative or estrogen receptor‐positive breast cancer dissemination and metastasis. This result held true whether analyzing Gedatolisib on its own (vs. vehicle‐treated animals) or in combination with dose‐dense doxorubicin and cyclophosphamide (vs. animals treated only with dose‐dense chemotherapies). These data suggest that PI3K is not the node downstream of integrin‐β1 that confers chemotherapeutic resistance to DTCs. More broadly, they cast doubt on the strategy to target PI3K in order to eliminate DTCs and prevent breast cancer metastasis.
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Affiliation(s)
- Ryann E Shor
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Jinxiang Dai
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Sun-Young Lee
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, CA, USA
| | - Laura Pisarsky
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Irina Matei
- Children's Cancer and Blood Foundation Laboratories, Department of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children's Health, Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Serena Lucotti
- Children's Cancer and Blood Foundation Laboratories, Department of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children's Health, Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - David Lyden
- Children's Cancer and Blood Foundation Laboratories, Department of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children's Health, Meyer Cancer Center, Weill Cornell Medicine, New York, NY, USA
| | - Mina J Bissell
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, CA, USA
| | - Cyrus M Ghajar
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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Mammadova-Bach E, Rupp T, Spenlé C, Jivkov I, Shankaranarayanan P, Klein A, Pisarsky L, Méchine-Neuville A, Cremel G, Kedinger M, De Wever O, Ambartsumian N, Robine S, Pencreach E, Guenot D, Simon-Assmann P, Goetz JG, Orend G, Lefebvre O. Laminin α1 orchestrates VEGFA functions in the ecosystem of colorectal carcinoma. Biol Cell 2018; 110:178-195. [PMID: 29907957 DOI: 10.1111/boc.201800007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/11/2018] [Accepted: 05/17/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND INFORMATION Tumor stroma remodeling is a key feature of malignant tumors and can promote cancer progression. Laminins are major constituents of basement membranes that physically separate the epithelium from the underlying stroma. RESULTS By employing mouse models expressing high and low levels of the laminin α1 chain (LMα1), we highlighted its implication in a tumor-stroma crosstalk, thus leading to increased colon tumor incidence, angiogenesis and tumor growth. The underlying mechanism involves attraction of carcinoma-associated fibroblasts by LMα1, VEGFA expression triggered by the complex integrin α2β1-CXCR4 and binding of VEGFA to LM-111, which in turn promotes angiogenesis, tumor cell survival and proliferation. A gene signature comprising LAMA1, ITGB1, ITGA2, CXCR4 and VEGFA has negative predictive value in colon cancer. CONCLUSIONS Together, we have identified VEGFA, CXCR4 and α2β1 integrin downstream of LMα1 in colon cancer as of bad prognostic value for patient survival. SIGNIFICANCE This information opens novel opportunities for diagnosis and treatment of colon cancer.
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Affiliation(s)
- Elmina Mammadova-Bach
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
- Inserm UMR-S 949, Etablissement Français du Sang-Alsace, Strasbourg, F-67065, France
| | - Tristan Rupp
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Caroline Spenlé
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Ivo Jivkov
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Pattabhiraman Shankaranarayanan
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Annick Klein
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Laura Pisarsky
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
- Public Health Sciences Division/Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, U.S.A
| | | | - Gérard Cremel
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Michèle Kedinger
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Olivier De Wever
- Laboratory of Experimental Cancer Research, Department of Radiotherapy and Nuclear Medicine, Ghent University Hospital, Ghent, 9000, Belgium
| | | | | | - Erwan Pencreach
- EA 3430, Université de Strasbourg, Strasbourg, F-67000, France
- Plateforme de Génétique Moléculaire des Cancers, Hôpitaux Universitaires de Strasbourg, Strasbourg, F-67098, France
| | | | - Patricia Simon-Assmann
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Jacky G Goetz
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Gertraud Orend
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
| | - Olivier Lefebvre
- Inserm U1109, MN3T, Strasbourg, F-67200, France
- Université de Strasbourg, Strasbourg, F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, F-67000, France
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Pisarsky L, Ghajar CM. Anti-angiogenic Therapy-Mediated Endothelial Damage: A Driver of Breast Cancer Recurrence? Advances in Experimental Medicine and Biology 2018; 1100:19-45. [DOI: 10.1007/978-3-319-97746-1_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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5
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Pisarsky L, Dai J, Ghajar CM. Taking inventory of metastasis effectors. Nat Med 2017; 23:275-276. [PMID: 28267712 DOI: 10.1038/nm.4301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Laura Pisarsky
- Public Health Sciences Division's Translational Research Program and the Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Jinxiang Dai
- Public Health Sciences Division's Translational Research Program and the Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Cyrus M Ghajar
- Public Health Sciences Division's Translational Research Program and the Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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Pisarsky L, Bill R, Fagiani E, Dimeloe S, Goosen RW, Hagmann J, Hess C, Christofori G. Targeting Metabolic Symbiosis to Overcome Resistance to Anti-angiogenic Therapy. Cell Rep 2016; 15:1161-74. [PMID: 27134168 PMCID: PMC4870473 DOI: 10.1016/j.celrep.2016.04.028] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 01/19/2016] [Accepted: 04/04/2016] [Indexed: 12/11/2022] Open
Abstract
Despite the approval of several anti-angiogenic therapies, clinical results remain unsatisfactory, and transient benefits are followed by rapid tumor recurrence. Here, we demonstrate potent anti-angiogenic efficacy of the multi-kinase inhibitors nintedanib and sunitinib in a mouse model of breast cancer. However, after an initial regression, tumors resume growth in the absence of active tumor angiogenesis. Gene expression profiling of tumor cells reveals metabolic reprogramming toward anaerobic glycolysis. Indeed, combinatorial treatment with a glycolysis inhibitor (3PO) efficiently inhibits tumor growth. Moreover, tumors establish metabolic symbiosis, illustrated by the differential expression of MCT1 and MCT4, monocarboxylate transporters active in lactate exchange in glycolytic tumors. Accordingly, genetic ablation of MCT4 expression overcomes adaptive resistance against anti-angiogenic therapy. Hence, targeting metabolic symbiosis may be an attractive avenue to avoid resistance development to anti-angiogenic therapy in patients. Tumors can escape anti-angiogenic therapy with multi-kinase inhibitors A glycolytic shift underlies resistance against multi-kinase inhibitors Metabolic symbiosis between hypoxic and oxygenated cells inspires therapy resistance Inhibition of glycolysis or lactate export collapses metabolic symbiosis
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Affiliation(s)
- Laura Pisarsky
- Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Ruben Bill
- Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Ernesta Fagiani
- Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Sarah Dimeloe
- Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | | | - Jörg Hagmann
- Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
| | - Christoph Hess
- Department of Biomedicine, University of Basel, 4058 Basel, Switzerland
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Fantozzi A, Gruber DC, Pisarsky L, Heck C, Kunita A, Yilmaz M, Meyer-Schaller N, Cornille K, Hopfer U, Bentires-Alj M, Christofori G. VEGF-mediated angiogenesis links EMT-induced cancer stemness to tumor initiation. Cancer Res 2014; 74:1566-75. [PMID: 24413534 DOI: 10.1158/0008-5472.can-13-1641] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An epithelial-mesenchymal transition (EMT) underlies malignant tumor progression and metastatic spread by enabling cancer cells to depart from the primary tumor, invade surrounding tissue, and disseminate to distant organs. EMT also enriches for cancer stem cells (CSC) and increases the capacity of cancer cells to initiate and propagate tumors upon transplantation into immune-deficient mice, a major hallmark of CSCs. However, the molecular mechanisms promoting the tumorigenicity of cancer cells undergoing an EMT and of CSCs have remained widely elusive. We here report that EMT confers efficient tumorigenicity to murine breast cancer cells by the upregulated expression of the proangiogenic factor VEGF-A and by increased tumor angiogenesis. On the basis of these data, we propose a novel interpretation of the features of CSCs with EMT-induced, VEGF-A-mediated angiogenesis as the connecting mechanism between cancer cell stemness and tumor initiation.
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Affiliation(s)
- Anna Fantozzi
- Authors' Affiliations: Department of Biomedicine, University of Basel; and Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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Zumsteg A, Caviezel C, Pisarsky L, Strittmatter K, García-Echeverría C, Hofmann F, Christofori G. Repression of malignant tumor progression upon pharmacologic IGF1R blockade in a mouse model of insulinoma. Mol Cancer Res 2012; 10:800-9. [PMID: 22562956 DOI: 10.1158/1541-7786.mcr-11-0522] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
NVP-AEW541, a specific ATP-competitive inhibitor of the insulin-like growth factor-1 receptor (IGF1R) tyrosine kinase, has been reported to interfere with tumor growth in various tumor transplantation models. We have assessed the efficacy of NVP-AEW541 in repressing tumor growth and tumor progression in the Rip1Tag2 transgenic mouse model of pancreatic β-cell carcinogenesis. In addition, we have tested NVP-AEW541 in Rip1Tag2;RipIGF1R double-transgenic mice which show accelerated tumor growth and increased tumor malignancy compared with Rip1Tag2 single-transgenic mice. Previously, we have shown that high levels of IGF-2, a high-affinity ligand for IGF1R, are required for Rip1Tag2 tumor cell survival and tumor growth. Unexpectedly, treatment of Rip1Tag2 mice with NVP-AEW541 in prevention and intervention trials neither did affect tumor growth nor tumor cell proliferation and apoptosis. Yet, it significantly repressed progression to tumor malignancy, that is, the rate of the transition from differentiated adenoma to invasive carcinoma. Treatment of Rip1Tag2;RipIGF1R double-transgenic mice resulted in moderately reduced tumor volumes and increased rates of tumor cell apoptosis. Sustained expression of IGF-2 and of the IGF-2-binding form of insulin receptor (IR-A) in tumor cells suggests a compensatory role of IR-A upon IGF1R blockade. The results indicate that inhibition of IGF1R alone is not sufficient to efficiently block insulinoma growth and imply an overlapping role of IGF1R and insulin receptor in executing mitogenic and survival stimuli elicited by IGF-2. The reduction of tumor invasion upon IGF1R blockade on the other hand indicates a critical function of IGF1R signaling for the acquisition of a malignant phenotype.
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Affiliation(s)
- Adrian Zumsteg
- Institute of Biochemistry and Genetics, Department of Biomedicine, University of Basel, Mattenstrasse 28, Basel 4058, Switzerland
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