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Hinz N, Jücker M. AKT in Bone Metastasis of Solid Tumors: A Comprehensive Review. Cancers (Basel) 2021; 13:cancers13102287. [PMID: 34064589 PMCID: PMC8151478 DOI: 10.3390/cancers13102287] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Bone metastasis is a frequent complication of solid tumors and leads to a reduced overall survival. Although much progress has been made in the field of tumor therapy in the last years, bone metastasis depicts a stage of the disease with a lack of appropriate therapeutical options. Hence, this review aims to present the role of AKT in bone metastasis of solid tumors to place the spotlight on AKT as a possible therapeutical approach for patients with bone metastases. Furthermore, we intended to discuss postulated underlying molecular mechanisms of the bone metastasis-promoting effect of AKT, especially in highly bone-metastatic breast, prostate, and lung cancer. To conclude, this review identified the AKT kinase as a potential therapeutical target in bone metastasis and revealed remaining questions, which need to be addressed in further research projects. Abstract Solid tumors, such as breast cancer and prostate cancer, often form bone metastases in the course of the disease. Patients with bone metastases frequently develop complications, such as pathological fractures or hypercalcemia and exhibit a reduced life expectancy. Thus, it is of vital importance to improve the treatment of bone metastases. A possible approach is to target signaling pathways, such as the PI3K/AKT pathway, which is frequently dysregulated in solid tumors. Therefore, we sought to review the role of the serine/threonine kinase AKT in bone metastasis. In general, activation of AKT signaling was shown to be associated with the formation of bone metastases from solid tumors. More precisely, AKT gets activated in tumor cells by a plethora of bone-derived growth factors and cytokines. Subsequently, AKT promotes the bone-metastatic capacities of tumor cells through distinct signaling pathways and secretion of bone cell-stimulating factors. Within the crosstalk between tumor and bone cells, also known as the vicious cycle, the stimulation of osteoblasts and osteoclasts also causes activation of AKT in these cells. As a consequence, bone metastasis is reduced after experimental inhibition of AKT. In summary, AKT signaling could be a promising therapeutical approach for patients with bone metastases of solid tumors.
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Bahmad HF, Jalloul M, Azar J, Moubarak MM, Samad TA, Mukherji D, Al-Sayegh M, Abou-Kheir W. Tumor Microenvironment in Prostate Cancer: Toward Identification of Novel Molecular Biomarkers for Diagnosis, Prognosis, and Therapy Development. Front Genet 2021; 12:652747. [PMID: 33841508 PMCID: PMC8033163 DOI: 10.3389/fgene.2021.652747] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/08/2021] [Indexed: 12/12/2022] Open
Abstract
Prostate cancer (PCa) is by far the most commonly diagnosed cancer in men worldwide. Despite sensitivity to androgen deprivation, patients with advanced disease eventually develop resistance to therapy and may die of metastatic castration-resistant prostate cancer (mCRPC). A key challenge in the management of PCa is the clinical heterogeneity that is hard to predict using existing biomarkers. Defining molecular biomarkers for PCa that can reliably aid in diagnosis and distinguishing patients who require aggressive therapy from those who should avoid overtreatment is a significant unmet need. Mechanisms underlying the development of PCa are not confined to cancer epithelial cells, but also involve the tumor microenvironment. The crosstalk between epithelial cells and stroma in PCa has been shown to play an integral role in disease progression and metastasis. A number of key markers of reactive stroma has been identified including stem/progenitor cell markers, stromal-derived mediators of inflammation, regulators of angiogenesis, connective tissue growth factors, wingless homologs (Wnts), and integrins. Here, we provide a synopsis of the stromal-epithelial crosstalk in PCa focusing on the relevant molecular biomarkers pertaining to the tumor microenvironment and their role in diagnosis, prognosis, and therapy development.
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Affiliation(s)
- Hisham F Bahmad
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Arkadi M. Rywlin M.D. Department of Pathology and Laboratory Medicine, Mount Sinai Medical Center, Miami Beach, FL, United States
| | - Mohammad Jalloul
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Joseph Azar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Maya M Moubarak
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Tamara Abdul Samad
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Deborah Mukherji
- Department of Internal Medicine, Division of Hematology-Oncology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Mohamed Al-Sayegh
- Biology Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Wassim Abou-Kheir
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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Galluzzi L, Vacchelli E, Fridman WH, Galon J, Sautès-Fridman C, Tartour E, Zucman-Rossi J, Zitvogel L, Kroemer G. Trial Watch: Monoclonal antibodies in cancer therapy. Oncoimmunology 2021; 1:28-37. [PMID: 22720209 DOI: 10.4161/onci.1.1.17938] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Since the advent of hybridoma technology, dating back to 1975, monoclonal antibodies have become an irreplaceable diagnostic and therapeutic tool for a wide array of human diseases. During the last 15 years, several monoclonal antibodies (mAbs) have been approved by FDA for cancer therapy. These mAbs are designed to (1) activate the immune system against tumor cells, (2) inhibit cancer cell-intrinsic signaling pathways, (3) bring toxins in the close proximity of cancer cells, or (4) interfere with the tumor-stroma interaction. More recently, major efforts have been made for the development of immunostimulatory mAbs that either enhance cancer-directed immune responses or limit tumor- (or therapy-) driven immunosuppression. Some of these antibodies, which are thought to facilitate tumor eradication by initiating or sustaining a tumor-specific immune response, have already entered clinical trials. In this Trial Watch, we will review and discuss the clinical progress of the most important mAbs that are have entered clinical trials after January 2008.
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Affiliation(s)
- Lorenzo Galluzzi
- INSERM, U848; Villejuif, France ; Institut Gustave Roussy; Villejuif, France ; Université Paris-Sud/Paris XI; Le Kremlin-Bicêtre, France
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Shang J, Gao ZY, Zhang LY, Wang CY. Over-expression of JAZF1 promotes cardiac microvascular endothelial cell proliferation and angiogenesis via activation of the Akt signaling pathway in rats with myocardial ischemia-reperfusion. Cell Cycle 2019; 18:1619-1634. [PMID: 31177938 PMCID: PMC6619954 DOI: 10.1080/15384101.2019.1629774] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Myocardial ischemia-reperfusion (I/R) injury is caused by endothelial dysfunction and enhanced oxidative stress. The overexpression of JAZF1, a zinc finger protein, has been reported to promote cell proliferation and suppress myogenic differentiation in type 2 diabetes. However, the involvement of JAZF1 in myocardial I/R injury remains to be unclear. The current study aims to investigate the role by which JAZF1 influences cardiac microvascular endothelial cells (CMECs) in a rat model of myocardial I/R injury. A total of 50 rats were established as a myocardial I/R model to isolate CMECs, with alterations in JAZF1 expression. After that, the gain- or loss-function of JAZF1 on the proliferation, apoptosis and tube formation ability of CMECs were evaluated by a series of in vitro experiments. Results indicated that JAZF1 was down-regulated in CMECs of rats with myocardial I/R injury. After treatment with JAZF1, the levels of VEGF, Bcl-2, PDGF and p-Akt/Akt were all increased; however, the expression of Bax, caspase-3, caspase-9, p-Bad/Bad, c-caspase-3/caspase-3, c-caspase-9/caspase-9, and p-FKHR/FKHR exhibited decreased levels; CMEC proliferation and angiogenesis were increased, while cell apoptosis was attenuated. CMECs transfected with JAZF1 shRNA exhibited the contrary tendencies. The key findings of this study suggest that the over-expression of JAZF1 alleviates myocardial I/R injury by enhancing proliferation and angiogenesis of CMECs and in turn inhibiting apoptosis of CMECs via the activation of the Akt signaling pathway.
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Affiliation(s)
- Jie Shang
- a Department of Electrocardiogram , Yantai Yuhuangding Hospital , Yantai , P. R. China
| | - Zhi-Yong Gao
- b Department of Rehabilitation , Yantai Yuhuangding Hospital , Yantai , P. R. China
| | - Li-Yan Zhang
- c Department of Cardiovascular Medicine , Longkou Nanshan Health Valley Tumor Hospital , Longkou , P.R. China
| | - Chun-Yu Wang
- a Department of Electrocardiogram , Yantai Yuhuangding Hospital , Yantai , P. R. China
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Moroncini G, Maccaroni E, Fiordoliva I, Pellei C, Gabrielli A, Berardi R. Developments in the management of advanced soft-tissue sarcoma - olaratumab in context. Onco Targets Ther 2018; 11:833-842. [PMID: 29497315 PMCID: PMC5820470 DOI: 10.2147/ott.s127609] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lartruvo® (olaratumab) is a fully human immunoglobulin G subclass 1 (IgG1) monoclonal antibody that inhibits platelet-derived growth factor receptor alpha (PDGFRα). The antitumor activity of olaratumab has been tested in vitro and in vivo, and inhibition of tumor growth has been observed in cancer cell lines, including glioblastoma and leiomyosarcoma cells. It represents the first-in-class antibody to be approved by regulatory authorities for the treatment of advanced soft-tissue sarcomas (STSs) in combination with doxorubicin, based on the results of the Phase Ib/II trial by Tap et al. The median progression-free survival (PFS), which was the primary end point of the study, was improved for patients treated with olaratumab plus doxorubicin compared to those treated with doxorubicin monotherapy (6.6 vs 4.1 months, respectively; HR 0.672, 95% CI 0.442-1.021, p=0.0615). Moreover, final analysis of overall survival (OS) showed a median OS of 26.5 months with olaratumab plus doxorubicin vs 14.7 months with doxorubicin, with a gain of 11.8 months (HR 0.46, 95% CI 0.30-0.71, p=0.0003). In October 2016, olaratumab was admitted in the Accelerated Approval Program by the US Food and Drug Administration (FDA) for use in combination with doxorubicin for the treatment of adult patients with STSs. In November 2016, the European Medicines Agency (EMA) granted conditional approval for olaratumab in the same indication under its Accelerated Assessment Program. A double-blind, placebo-controlled, randomized Phase III study (ANNOUNCE trial, NCT02451943) is being performed in order to confirm the survival advantage of olaratumab and to provide definitive drug confirmation by regulators. The study is ongoing, but enrollment is closed. The purpose of this review was to evaluate the rationale of olaratumab in the treatment of advanced STSs and its emerging role in clinical practice.
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Affiliation(s)
- Gianluca Moroncini
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, Ancona, Italy
| | - Elena Maccaroni
- Medical Oncology Unit, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti Umberto I, GM Lancisi, G Salesi, Ancona, Italy
| | - Ilaria Fiordoliva
- Medical Oncology Unit, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti Umberto I, GM Lancisi, G Salesi, Ancona, Italy
| | - Chiara Pellei
- Medical Oncology Unit, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti Umberto I, GM Lancisi, G Salesi, Ancona, Italy
| | - Armando Gabrielli
- Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, Ancona, Italy
| | - Rossana Berardi
- Medical Oncology Unit, Università Politecnica delle Marche, Azienda Ospedaliero-Universitaria Ospedali Riuniti Umberto I, GM Lancisi, G Salesi, Ancona, Italy
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Wagner AJ, Kindler H, Gelderblom H, Schöffski P, Bauer S, Hohenberger P, Kopp HG, Lopez-Martin JA, Peeters M, Reichardt P, Qin A, Nippgen J, Ilaria RL, Rutkowski P. A phase II study of a human anti-PDGFRα monoclonal antibody (olaratumab, IMC-3G3) in previously treated patients with metastatic gastrointestinal stromal tumors. Ann Oncol 2017; 28:541-546. [PMID: 28426120 PMCID: PMC5391707 DOI: 10.1093/annonc/mdw659] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Background This study evaluated tumor response to olaratumab (an anti-PDGFRα monoclonal antibody) in previously treated patients with metastatic gastrointestinal stromal tumor (GIST) with or without PDGFRα mutations (cohorts 1 and 2, respectively). Patients and methods Patients received olaratumab 20 mg/kg intravenously every 14 days until disease progression, death, or intolerable toxicity occurred. Outcome measures were 12-week tumor response, progression-free survival (PFS), overall survival (OS), and safety. Results Of 30 patients enrolled, 21 patients received ≥1 dose of olaratumab. In the evaluable population (cohort 1, n = 6; cohort 2, n = 14), no complete response (CR) or partial response (PR) was observed. Stable disease (SD) was observed in 3 patients (50.0%) in cohort 1 and 2 patients (14.3%) in cohort 2. Progressive disease (PD) was observed in 3 patients (50.0%) in cohort 1 and 12 patients (85.7%) in cohort 2. The 12-week clinical benefit rate (CR + PR + SD) (90% CI) was 50.0% (15.3–84.7%) in cohort 1 and 14.3% (2.6–38.5%) in cohort 2. SD lasted beyond 12 weeks in 5 patients (cohort 1, n = 3; cohort 2, n = 2). Median PFS (90% CI) was 32.1 (5.0–35.9) weeks in cohort 1 and 6.1 (5.7–6.3) weeks in cohort 2. Median OS was not reached in cohort 1 and was 24.9 (14.4–49.1) weeks in cohort 2. All patients in cohort 1 and 9 (64.3%) in cohort 2 experienced an olaratumab-related adverse event (AE), most commonly fatigue (38.1%), nausea (19.0%), and peripheral edema (14.3%). Two grade ≥3 olaratumab-related events were reported (cohort 1, syncope; cohort 2, hypertension). Conclusions Olaratumab had an acceptable AE profile in patients with GIST. While there was no apparent effect on PFS in patients without PDGFRα mutations, patients with PDGFRα-mutant GIST (all with D842V mutations) treated with olaratumab had longer disease control compared with historical data for this genotype. ClinicalTrials.gov Identifier NCT01316263.
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Affiliation(s)
- A J Wagner
- Center for Sarcoma and Bone Oncology, Dana-Farber Cancer Institute, Boston
| | - H Kindler
- University of Chicago Medical School, Chicago, USA
| | - H Gelderblom
- Leids Universitair Medisch Centrum, Leiden, Netherlands
| | - P Schöffski
- Leuven Cancer Institute, University Hospitals Leuven, KU Leuven, Leuven, Belgium
| | - S Bauer
- West German Cancer Center, University of Duisburg-Essen, Essen, and German Cancer Consortium, Heidelberg
| | - P Hohenberger
- Division of Surgical Oncology and Thoracic Surgery, Medical Faculty Mannheim, University of Heidelberg, Mannheim
| | - H-G Kopp
- Department of Oncology and Hematology, Tuebingen University Medical Center, Tuebingen, Germany
| | - J A Lopez-Martin
- 12 de Octubre University Hospital and Research Institute, Madrid, Spain
| | - M Peeters
- Universitair Ziekenhuis Antwerpen, Antwerp, Belgium
| | - P Reichardt
- HELIOS Klinikum Berlin-Buch, Berlin, Germany
| | - A Qin
- Eli Lilly and Company, Indianapolis, USA
| | - J Nippgen
- Merck KGaA (Formerly ImClone Medical), Darmstadt, Germany
| | - R L Ilaria
- Eli Lilly and Company, Indianapolis, USA
| | - P Rutkowski
- Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
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Olaratumab Exerts Antitumor Activity in Preclinical Models of Pediatric Bone and Soft Tissue Tumors through Inhibition of Platelet-Derived Growth Factor Receptor α. Clin Cancer Res 2017; 24:847-857. [DOI: 10.1158/1078-0432.ccr-17-1258] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/07/2017] [Accepted: 11/28/2017] [Indexed: 11/16/2022]
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Mashreghi M, Azarpara H, Bazaz MR, Jafari A, Masoudifar A, Mirzaei H, Jaafari MR. Angiogenesis biomarkers and their targeting ligands as potential targets for tumor angiogenesis. J Cell Physiol 2017; 233:2949-2965. [DOI: 10.1002/jcp.26049] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/12/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Mohammad Mashreghi
- NanotechnologyResearch Center; Mashhad University of Medical Sciences; Mashhad Iran
- School of Pharmacy; Mashhad University of Medical Sciences; Mashhad Iran
| | - Hassan Azarpara
- School of Medicine; Iran University of Medical Sciences; Tehran Iran
| | - Mahere R. Bazaz
- Division of Biotechnology, Faculty of Veterinary Medicine; Ferdowsi University of Mashhad; Mashhad Iran
| | - Arash Jafari
- School of Medicine; Birjand University of Medical Sciences; Birjand Iran
| | - Aria Masoudifar
- Department of Molecular Biotechnology, Cell Science Research Center; Royan Institute for Biotechnology; ACECR Isfahan Iran
| | - Hamed Mirzaei
- Department of Medical Biotechnology, School of Medicine; Mashhad University of Medical Sciences; Mashhad Iran
| | - Mahmoud R. Jaafari
- NanotechnologyResearch Center; Mashhad University of Medical Sciences; Mashhad Iran
- School of Pharmacy; Mashhad University of Medical Sciences; Mashhad Iran
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Lewandowski SA, Fredriksson L, Lawrence DA, Eriksson U. Pharmacological targeting of the PDGF-CC signaling pathway for blood-brain barrier restoration in neurological disorders. Pharmacol Ther 2016; 167:108-119. [PMID: 27524729 PMCID: PMC5341142 DOI: 10.1016/j.pharmthera.2016.07.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/25/2016] [Indexed: 12/12/2022]
Abstract
Neurological disorders account for a majority of non-malignant disability in humans and are often associated with dysfunction of the blood-brain barrier (BBB). Recent evidence shows that despite apparent variation in the origin of neural damage, the central nervous system has a common injury response mechanism involving platelet-derived growth factor (PDGF)-CC activation in the neurovascular unit and subsequent dysfunction of BBB integrity. Inhibition of PDGF-CC signaling with imatinib in mice has been shown to prevent BBB dysfunction and have neuroprotective effects in acute damage conditions, including traumatic brain injury, seizures or stroke, as well as in neurodegenerative diseases that develop over time, including multiple sclerosis and amyotrophic lateral sclerosis. Stroke and traumatic injuries are major risk factors for age-associated neurodegenerative disorders and we speculate that restoring BBB properties through PDGF-CC inhibition might provide a common therapeutic opportunity for treatment of both acute and progressive neuropathology in humans. In this review we will summarize what is known about the role of PDGF-CC in neurovascular signaling events and the variety of seemingly different neuropathologies it is involved in. We will also discuss the pharmacological means of therapeutic interventions for anti-PDGF-CC therapy and ongoing clinical trials. In summary: inhibition of PDGF-CC signaling can be protective for immediate injury and decrease the long-term neurodegenerative consequences.
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Affiliation(s)
- Sebastian A Lewandowski
- Tissue Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles v. 2, 17177, Stockholm, Sweden.
| | - Linda Fredriksson
- Vascular Biology Groups, Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles v. 2, 17177, Stockholm, Sweden; Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, 7301 Medical Science Research Building III, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0644, USA
| | - Daniel A Lawrence
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, 7301 Medical Science Research Building III, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0644, USA
| | - Ulf Eriksson
- Tissue Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles v. 2, 17177, Stockholm, Sweden.
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Vascular Endothelial Cell Growth Factor A Acts via Platelet-Derived Growth Factor Receptor α To Promote Viability of Cells Enduring Hypoxia. Mol Cell Biol 2016; 36:2314-27. [PMID: 27325673 DOI: 10.1128/mcb.01019-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 06/07/2016] [Indexed: 12/20/2022] Open
Abstract
Vascular endothelial cell growth factor A (VEGF) is a biologically and therapeutically important growth factor because it promotes angiogenesis in response to hypoxia, which underlies a wide variety of both physiological and pathological settings. We report here that both VEGF receptor 2 (VEGFR2)-positive and -negative cells depended on VEGF to endure hypoxia. VEGF enhanced the viability of platelet-derived growth factor receptor α (PDGFRα)-positive and VEGFR2-negative cells by enabling indirect activation of PDGFRα, thereby reducing the level of p53. We conclude that the breadth of VEGF's influence extends beyond VEGFR-positive cells and propose a plausible mechanistic explanation of this phenomenon.
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Platelet Derived Growth Factor Has a Role in Pressure Induced Bladder Smooth Muscle Cell Hyperplasia and Acts in a Paracrine Way. J Urol 2015; 194:1797-805. [DOI: 10.1016/j.juro.2015.05.092] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2015] [Indexed: 12/17/2022]
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Kikuchi A, Monga SP. PDGFRα in liver pathophysiology: emerging roles in development, regeneration, fibrosis, and cancer. Gene Expr 2015; 16:109-27. [PMID: 25700367 PMCID: PMC4410163 DOI: 10.3727/105221615x14181438356210] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Platelet-derived growth factor receptor α (PDGFRα) is an isoform of the PDGFR family of tyrosine kinase receptors involved in cell proliferation, survival, differentiation, and growth. In this review, we highlight the role of PDGFRα and the current evidence of its expression and activities in liver development, regeneration, and pathology-including fibrosis, cirrhosis, and liver cancer. Studies elucidating PDGFRα signaling in processes ranging from profibrotic signaling, angiogenesis, and oxidative stress to epithelial-to-mesenchymal transition point toward PDGFRα as a potential therapeutic target in various hepatic pathologies, including hepatic fibrosis and liver cancer. Furthermore, PDGFRα localization and modulation during liver development and regeneration may lend insight into its potential roles in various pathologic states. We will also briefly discuss some of the current targeted treatments for PDGFRα, including multi receptor tyrosine kinase inhibitors and PDGFRα-specific inhibitors.
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Affiliation(s)
- Alexander Kikuchi
- Department of Pathology and Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Weigel MT, Rath K, Alkatout I, Wenners AS, Schem C, Maass N, Jonat W, Mundhenke C. Nilotinib in combination with carboplatin and paclitaxel is a candidate for ovarian cancer treatment. Oncology 2014; 87:232-45. [PMID: 25116401 DOI: 10.1159/000363656] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 04/28/2014] [Indexed: 11/19/2022]
Abstract
PURPOSE Nilotinib is a selective tyrosine kinase inhibitor of c-Kit, Abl and platelet-derived growth factor receptor-α/β. To evaluate nilotinib's potential use as a treatment of human ovarian cancer, we tested nilotinib's preclinical activity in ovarian cancer cell lines with different tyrosine kinase expression patterns. METHODS The effects of nilotinib on ovarian cancer cell growth were studied alone and in combination with carboplatin and paclitaxel. Proapoptotic and antimigratory effects were examined using TUNEL and migration assays. RESULTS Nilotinib alone and in combination with carboplatin and paclitaxel significantly inhibited cell growth in PDGFR-α-positive ovarian cancer cell lines. The combination of nilotinib with carboplatin and paclitaxel showed synergistic effects on cell proliferation. Nilotinib treatment led to the inhibition of cell migration alone and in combination with carboplatin and paclitaxel. Apoptosis induction occurred in response to nilotinib that increased in combination with carboplatin. CONCLUSIONS Nilotinib may be a feasible targeted therapy option for the treatment of ovarian cancer.
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Affiliation(s)
- Marion T Weigel
- Department of Gynecology and Obstetrics, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
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Chiorean EG, Sweeney C, Youssoufian H, Qin A, Dontabhaktuni A, Loizos N, Nippgen J, Amato R. A phase I study of olaratumab, an anti-platelet-derived growth factor receptor alpha (PDGFRα) monoclonal antibody, in patients with advanced solid tumors. Cancer Chemother Pharmacol 2014; 73:595-604. [PMID: 24452395 DOI: 10.1007/s00280-014-2389-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 01/13/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE The platelet-derived growth factor receptor (PDGFR) has an important role in tumorigenesis and tumor progression. Olaratumab (IMC-3G3) is a fully human monoclonal antibody that selectively binds human PDGFRα and blocks ligand binding. This phase I study assessed the safety, maximum tolerated dose (MTD), recommended phase II dose (RP2D), pharmacokinetics, and preliminary antitumor activity of olaratumab in patients with advanced solid tumors. METHODS Patients were enrolled into five dose-escalating cohorts of 3-6 patients each. Olaratumab was administered intravenously weekly at 4, 8, or 16 mg/kg (cohorts 1-3) or once every other week at 15 or 20 mg/kg (cohorts 4-5), with 4 weeks/cycle. RESULTS Nineteen patients were treated in five cohorts. There were no dose-limiting toxicities; the MTD was not identified with the doses studied. The most common olaratumab-related adverse events (AE) were fatigue and infusion reactions (10.5 % each). With the exception of 1 patient (20 mg/kg) experiencing two grade 3 drug-related AEs after the dose-limiting toxicity assessment period, all drug-related AEs were grade 1 or 2. The trough concentrations (C min) for 16 mg/kg weekly and 20 mg/kg biweekly were higher than 155 μg/mL, and the concentration found to be efficacious in preclinical xenograft models. Twelve patients (63.2 %) had a best response of stable disease [median duration of 3.9 months (95 % CI 2.3-8.7)]. CONCLUSIONS Olaratumab was well tolerated and showed preliminary antitumor activity. RP2Ds are 16 mg/kg weekly and 20 mg/kg biweekly. Phase II studies of olaratumab as monotherapy and in combination are ongoing in several tumor types.
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Affiliation(s)
- E Gabriela Chiorean
- Fred Hutchinson Cancer Research Center, University of Washington, 825 Eastlake Ave East, G4830, Seattle, WA, 98109, USA,
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Pennock S, Haddock LJ, Eliott D, Mukai S, Kazlauskas A. Is neutralizing vitreal growth factors a viable strategy to prevent proliferative vitreoretinopathy? Prog Retin Eye Res 2014; 40:16-34. [PMID: 24412519 DOI: 10.1016/j.preteyeres.2013.12.006] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/23/2013] [Accepted: 12/27/2013] [Indexed: 11/18/2022]
Abstract
Proliferative vitreoretinopathy (PVR) is a blinding disorder that occurs in eyes with rhegmatogenous retinal detachment and in eyes that have recently undergone retinal detachment surgery. There are presently no treatment strategies to reduce the risk of developing PVR in eyes with retinal detachment, and surgical intervention is the only option for eyes with retinal detachment and established PVR. Given the poor visual outcome associated with the surgical treatment of PVR, considerable work has been done to identify pharmacologic agents that could antagonize the PVR process. Intensive efforts to identify molecular determinants of PVR implicate vitreal growth factors. A surprise that emerged in the course of testing the 'growth factor hypothesis' of PVR was the existence of a functional relationship amongst growth factors that engage platelet-derived growth factor (PDGF) receptor α (PDGFRα), a receptor tyrosine kinase that is key to pathogenesis of experimental PVR. Vascular endothelial cell growth factor A (VEGF), which is best known for its ability to activate VEGF receptors (VEGFRs) and induce permeability and/or angiogenesis, enables activation of PDGFRα by a wide spectrum of vitreal growth factors outside of the PDGF family (non-PDGFs) in a way that triggers signaling events that potently enhance the viability of cells displaced into vitreous. Targeting these growth factors or signaling events effectively neutralizes the bioactivity of PVR vitreous and prevents PVR in a number of preclinical models. In this review, we discuss recent conceptual advances in understanding the role of growth factors in PVR, and consider the tangible treatment strategies for clinical application.
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Affiliation(s)
- Steven Pennock
- The Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Luis J Haddock
- The Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Dean Eliott
- The Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Shizuo Mukai
- The Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Andrius Kazlauskas
- The Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
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Heldin CH. Targeting the PDGF signaling pathway in tumor treatment. Cell Commun Signal 2013; 11:97. [PMID: 24359404 PMCID: PMC3878225 DOI: 10.1186/1478-811x-11-97] [Citation(s) in RCA: 329] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 12/11/2013] [Indexed: 01/15/2023] Open
Abstract
Platelet-derived growth factor (PDGF) isoforms and PDGF receptors have important functions in the regulation of growth and survival of certain cell types during embryonal development and e.g. tissue repair in the adult. Overactivity of PDGF receptor signaling, by overexpression or mutational events, may drive tumor cell growth. In addition, pericytes of the vasculature and fibroblasts and myofibroblasts of the stroma of solid tumors express PDGF receptors, and PDGF stimulation of such cells promotes tumorigenesis. Inhibition of PDGF receptor signaling has proven to useful for the treatment of patients with certain rare tumors. Whether treatment with PDGF/PDGF receptor antagonists will be beneficial for more common malignancies is the subject for ongoing studies.
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Affiliation(s)
- Carl-Henrik Heldin
- Ludwig Institute for Cancer Research, Science for life laboratory, Uppsala University, Box 595SE-751 24 Uppsala, Sweden.
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Burch TC, Watson MT, Nyalwidhe JO. Variable metastatic potentials correlate with differential plectin and vimentin expression in syngeneic androgen independent prostate cancer cells. PLoS One 2013; 8:e65005. [PMID: 23717685 PMCID: PMC3661497 DOI: 10.1371/journal.pone.0065005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 04/24/2013] [Indexed: 12/30/2022] Open
Abstract
Prostate cancer is a clinically heterogeneous disease, ranging from indolent asymptomatic disease to very aggressive metastatic and life threatening forms of the disease. Distant metastasis represents the major lethal cause of prostate cancer. The most critical clinical challenge in the management of the patients is identifying those individuals at risk of developing metastatic disease. To understand the molecular mechanisms of prostate cancer metastasis and identify markers with metastatic potential, we have analyzed protein expression in two syngeneic prostate cancer cells lines PC3-N2 and PC3-ML2 using isobaric tags for relative and absolute quantitation labeling and multi-dimensional protein identification technology liquid chromatography matrix assisted laser desorption ionization tandem mass spectrometry. PC3-N2 is lowly metastatic while PC3-ML2 highly metastatic. A total of 1,756 proteins were identified in the analyses with 130 proteins showing different expression levels (p<0.01) in the two cell lines. Out of these, 68 proteins were found to be significantly up-regulated while 62 are significantly down-regulated in PC3-ML2 cells compared with PC3-N2 cells. The upregulation of plectin and vimentin which were the most significantly differentially expressed were validated by Western blot and their functional relevance with respect to invasion and migration was determined by siRNA gene silencing. To our knowledge, this study is the first to demonstrate that up-regulation of vimentin and plectin expression positively correlates with the invasion and metastasis of androgen-independent PCA.
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Affiliation(s)
- Tanya C. Burch
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America
- Leroy T. Canoles Jr. Cancer Research Center, Eastern Virginia Medical School, Norfolk, Virginia, United States of America
| | - Megan T. Watson
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America
- Leroy T. Canoles Jr. Cancer Research Center, Eastern Virginia Medical School, Norfolk, Virginia, United States of America
| | - Julius O. Nyalwidhe
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America
- Leroy T. Canoles Jr. Cancer Research Center, Eastern Virginia Medical School, Norfolk, Virginia, United States of America
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Liu Q, Jernigan D, Zhang Y, Fatatis A. Implication of platelet-derived growth factor receptor alpha in prostate cancer skeletal metastasis. CHINESE JOURNAL OF CANCER 2012; 30:612-9. [PMID: 21880182 PMCID: PMC4013323 DOI: 10.5732/cjc.011.10225] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Metastasis represents by far the most feared complication of prostate carcinoma and is the main cause of death for patients. The skeleton is frequently targeted by disseminated cancer cells and represents the sole site of spread in more than 80% of prostate cancer cases. Compatibility between select malignant phenotypes and the microenvironment of colonized tissues is broadly recognized as the culprit for the organ-tropism of cancer cells. Here, we review our recent studies showing that the expression of platelet-derived growth factor receptor alpha (PDGFRα ) supports the survival and growth of prostate cancer cells in the skeleton and that the soluble fraction of bone marrow activates PDGFRα in a ligand-independent fashion. Finally, we offer pre-clinical evidence that this receptor is a viable target for therapy.
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Affiliation(s)
- Qingxin Liu
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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19
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Jamieson-Gladney WL, Zhang Y, Fong AM, Meucci O, Fatatis A. The chemokine receptor CX₃CR1 is directly involved in the arrest of breast cancer cells to the skeleton. Breast Cancer Res 2011; 13:R91. [PMID: 21933397 PMCID: PMC3262203 DOI: 10.1186/bcr3016] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 08/02/2011] [Accepted: 09/20/2011] [Indexed: 02/07/2023] Open
Abstract
Introduction Skeletal metastases from breast adenocarcinoma are responsible for most of the morbidity and mortality associated with this tumor and represent a significant and unmet need for therapy. The arrival of circulating cancer cells to the skeleton depends first on the adhesive interactions with the endothelial cells lining the bone marrow sinusoids, and then the extravasation toward chemoattractant molecules produced by the surrounding bone stroma. We have previously shown that the membrane-bound and cell-adhesive form of the chemokine fractalkine is exposed on the luminal side of human bone marrow endothelial cells and that bone stromal cells release the soluble and chemoattractant form of this chemokine. The goal of this study was to determine the role of fractalkine and its specific receptor CX3CR1 in the homing of circulating breast cancer cells to the skeleton. Methods We employed a powerful pre-clinical animal model of hematogenous metastasis, in which fluorescent cancer cells are identified immediately after their arrival to the bone. We engineered cells to over-express either wild-type or functional mutants of CX3CR1 as well as employed transgenic mice knockout for fractalkine. Results CX3CR1 protein is detected in human tissue microarrays of normal and malignant mammary glands. We also found that breast cancer cells expressing high levels of this receptor have a higher propensity to spread to the skeleton. Furthermore, studies with fractalkine-null transgenic mice indicate that the ablation of the adhesive and chemotactic ligand of CX3CR1 dramatically impairs the skeletal dissemination of circulating cancer cells. Finally, we conclusively confirmed the crucial role of CX3CR1 on breast cancer cells for both adhesion to bone marrow endothelium and extravasation into the bone stroma. Conclusions We provide compelling evidence that the functional interactions between fractalkine produced by both the endothelial and stromal cells of bone marrow and the CX3CR1 receptor on breast cancer cells are determinant in the arrest and initial lodging needed for skeletal dissemination.
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Affiliation(s)
- Whitney L Jamieson-Gladney
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N 15th Street, Philadelphia, PA 19102-1101, USA
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Pathological signaling via platelet-derived growth factor receptor {alpha} involves chronic activation of Akt and suppression of p53. Mol Cell Biol 2011; 31:1788-99. [PMID: 21357737 DOI: 10.1128/mcb.01321-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In contrast to direct activation of platelet-derived growth factor (PDGF) receptor α (PDGFRα) via PDGF, indirect activation via growth factors outside the PDGF family failed to induce dimerization, internalization, and degradation of PDGFRα. Chronically activated, monomeric PDGFRα induced prolonged activation of Akt and suppressed the level of p53. These events were sufficient to promote both cellular responses (proliferation, survival, and contraction) that are intrinsic to proliferative vitreoretinopathy (PVR) and induce the disease itself. This signature signaling pathway appeared to extend beyond PVR since deregulating PDGFRα in ways that promote solid tumors also resulted in chronic activation of Akt and a decline in the level of p53.
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21
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Shao M, Rossi S, Chelladurai B, Shimizu M, Ntukogu O, Ivan M, Calin GA, Matei D. PDGF induced microRNA alterations in cancer cells. Nucleic Acids Res 2011; 39:4035-47. [PMID: 21266476 PMCID: PMC3105413 DOI: 10.1093/nar/gkq1305] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Platelet derived growth factor (PDGF) regulates gene transcription by binding to specific receptors. PDGF plays a critical role in oncogenesis in brain and other tumors, regulates angiogenesis, and remodels the stroma in physiologic conditions. Here, we show by using microRNA (miR) arrays that PDGFs regulate the expression and function of miRs in glioblastoma and ovarian cancer cells. The two PDGF ligands AA and BB affect expression of several miRs in ligand-specific manner; the most robust changes consisting of let-7d repression by PDGF-AA and miR-146b induction by PDGF-BB. Induction of miR-146b by PDGF-BB is modulated via MAPK-dependent induction of c-fos. We demonstrate that PDGF regulates expression of some of its known targets (e.g. cyclin D1) through miR alterations and identify the epidermal growth factor receptor (EGFR) as a new PDGF-BB target. We show that its expression and function are repressed by PDGF-induced miR-146b and that mir-146b and EGFR correlate inversely in human glioblastomas. We propose that PDGF-regulated gene transcription involves alterations in non-coding RNAs and provide evidence for a miR-dependent feedback mechanism balancing growth factor receptor signaling in cancer cells.
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Affiliation(s)
- Minghai Shao
- Department of Medicine, Indiana University School of Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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22
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Cancer: evolutionary, genetic and epigenetic aspects. Clin Epigenetics 2010; 1:85-100. [PMID: 22704202 PMCID: PMC3365664 DOI: 10.1007/s13148-010-0010-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 08/31/2010] [Indexed: 12/22/2022] Open
Abstract
There exist two paradigms about the nature of cancer. According to the generally accepted one, cancer is a by-product of design limitations of a multi-cellular organism (Greaves, Nat Rev Cancer 7:213–221, 2007). The essence of the second resides in the question “Does cancer kill the individual and save the species?” (Sommer, Hum Mutat 3:166–169, 1994). Recent data on genetic and epigenetic mechanisms of cell transformation summarized in this review support the latter point of view, namely that carcinogenesis is an evolutionary conserved phenomenon—a programmed death of an organism. It is assumed that cancer possesses an important function of altruistic nature: as a mediator of negative selection, it serves to preserve integrity of species gene pool and to mediate its evolutionary adjustment. Cancer fulfills its task due apparently to specific killer function, understanding mechanism of which may suggest new therapeutic strategy.
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23
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Russell MR, Liu Q, Fatatis A. Targeting the {alpha} receptor for platelet-derived growth factor as a primary or combination therapy in a preclinical model of prostate cancer skeletal metastasis. Clin Cancer Res 2010; 16:5002-10. [PMID: 20813817 DOI: 10.1158/1078-0432.ccr-10-1863] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Platelet-derived growth factor α (PDGFRα) is highly expressed in primary prostate cancer and associated skeletal metastases. Here, we tested whether targeting this receptor could impair metastatic colonization and progression, as well as prolong survival, either as primary or as combination therapy. EXPERIMENTAL DESIGN We used a preclinical animal model of metastasis in which PC3-ML human prostate cancer cells are inoculated directly in the blood circulation. First, the humanized, monoclonal antibody IMC-3G3 was administered to mice bearing established skeletal metastases. Second, we targeted the stromal PDGFRα with IMC-1E10, an antibody specific for the murine receptor. Third, IMC-3G3 and the bisphosphonate zoledronic acid (ZA), administered separately or in combination, were tested on the progression of skeletal lesions and overall survival. In addition, the ability of IMC-3G3 and ZA to impair initial colonization of the bone marrow by prostate cancer cells was investigated. RESULTS The blockade of PDGFRα on prostate cancer cells by IMC-3G3 reduces the size of established skeletal metastases, whereas the IMC-1E10 antibody directed against the stromal PDGFRα fails to inhibit metastatic progression. IMC-3G3 and ZA, either separately or in combination, significantly slow tumor growth and seem to prolong survival. Lastly, the blockade of PDGFRα by IMC-3G3 inhibits the initial phase of bone colonization, whereas ZA is ineffective at this stage. CONCLUSION This study presents compelling evidence that targeting PDGFRα with IMC-3G3 delays the progression of early metastatic foci and reduces the size of more established lesions. In addition, IMC-3G3, either alone or in combination with ZA, prolongs survival in animal models.
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Affiliation(s)
- Mike R Russell
- Departments of Pharmacology and Physiology, Laboratory Medicine, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
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24
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Russell MR, Liu Q, Lei H, Kazlauskas A, Fatatis A. The alpha-receptor for platelet-derived growth factor confers bone-metastatic potential to prostate cancer cells by ligand- and dimerization-independent mechanisms. Cancer Res 2010; 70:4195-203. [PMID: 20442296 DOI: 10.1158/0008-5472.can-09-4712] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Prostate adenocarcinoma is the second leading cause of cancer death among men, due primarily to the fact that the majority of prostate cancers will eventually spread to the skeleton. Metastatic dissemination requires a complex series of coordinated events that result in cells that escape from the primary tumor into the circulation and eventually colonize a distant organ. The ability of these cells to evolve into macroscopic metastases depends strongly on their compatibility with, and ability to utilize, this new microenvironment. We previously showed that bone-metastatic prostate cancer cells exposed to human bone marrow respond by activation of cell survival pathways, such as phosphoinositide 3-kinase/Akt, and that these events are mediated by the alpha-receptor for platelet-derived growth factor (PDGFRalpha). Our studies and others have shown that PDGFRalpha may be activated by mechanisms independent of PDGF ligand binding. Here, we provide conclusive evidence that soluble components of human bone marrow can activate PDGFRalpha through a mechanism that does not require the canonical binding of PDGF ligand(s) to the receptor. In particular, we found that dimerization of PDGFRalpha monomers is not induced by human bone marrow, but this does not prevent receptor phosphorylation and downstream signaling from occurring. To establish the relevance of this phenomenon in vivo, we used a PDGFRalpha mutant lacking the extracellular ligand-binding domain. Our studies show that this truncated PDGFRalpha is able to restore bone-metastatic potential of prostate cancer cells as effectively as the full-length form of the receptor.
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Affiliation(s)
- Mike R Russell
- Department of Pharmacology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA
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25
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Osteoblasts modulate Ca2+ signaling in bone-metastatic prostate and breast cancer cells. Clin Exp Metastasis 2009; 26:955-64. [PMID: 19768662 DOI: 10.1007/s10585-009-9286-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 09/01/2009] [Indexed: 12/20/2022]
Abstract
Metastatic prostate and breast cancers display a predilection for the skeleton. The high incidence of skeletal metastasis may be a reflection of favorable reciprocal interactions between the bone microenvironment and disseminated cancer cells. Here we show that bone-metastatic PC3-ML prostate cancer cells and MDA-231 breast cancer cells-when co-cultured with human osteoblasts-down-regulate the increase in cytosolic free calcium (Ca(2+)) induced by agonist stimulation. This osteoblast promoted alteration of Ca(2+) signaling develops and reverts in a time-dependent manner. Most importantly, the Ca(2+) responses of cancer cells lacking bone metastatic potential are not affected by osteoblasts. The limited increase in cytosolic Ca(2+) observed in bone-metastatic cells does not result from depleted intracellular Ca(2+) stores but rather a decreased entry of Ca(2+) from the extracellular space. Interestingly, the inhibition of histone deacetylase in cancer cells replicates the changes in Ca(2+) signaling induced by osteoblasts, suggesting the participation of epigenetic mechanisms. Finally, cancer cells harvested from skeletal metastases induced in mice showed Ca(2+) responses identical to cells co-cultured with osteoblasts. However, Ca(2+) signaling in cancer cells recovered from metastases to soft-tissues was not affected, emphasizing the role of the bone microenvironment in regulating the functional behavior of bone-metastatic cells. We propose that osteoblasts protect selected malignant phenotypes from cell death caused by an excessive increase in cytosolic Ca(2+), thereby facilitating their progression into macroscopic skeletal metastases.
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Lei H, Velez G, Hovland P, Hirose T, Gilbertson D, Kazlauskas A. Growth factors outside the PDGF family drive experimental PVR. Invest Ophthalmol Vis Sci 2009; 50:3394-403. [PMID: 19324843 DOI: 10.1167/iovs.08-3042] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Proliferative vitreoretinopathy (PVR) is a recurring and problematic disease for which there is no pharmacologic treatment. Platelet-derived growth factor (PDGF) in the vitreous is associated with experimental and clinical PVR. Furthermore, PDGF receptors (PDGFRs) are present and activated in epiretinal membranes of patient donors, and they are essential for experimental PVR. These observations suggest that PVR arises at least in part from PDGF/PDGFR-driven events. The goal of this study was to determine whether PDGFs were a potential therapeutic target for PVR. METHODS Experimental PVR was induced in rabbits by injecting fibroblasts. Vitreous specimens were collected from experimental rabbits or from patients undergoing vitrectomy to repair retinal detachment. A neutralizing PDGF antibody and a PDGF Trap were tested for their ability to prevent experimental PVR. Activation of PDGFR was monitored by antiphosphotyrosine Western blot analysis of immunoprecipitated PDGFRs. Contraction of collagen gels was monitored in vitro. RESULTS Neutralizing vitreal PDGFs did not effectively attenuate PVR, even though the reagents used potently blocked PDGF-dependent activation of the PDGF alpha receptor (PDGFRalpha). Vitreal growth factors outside the PDGF family modestly activated PDGFRalpha and appeared to do so without engaging the ligand-binding domain of PDGFRalpha. This indirect route to activate PDGFRalpha had profound functional consequences. It promoted the contraction of collagen gels and appeared sufficient to drive experimental PVR. CONCLUSIONS Although PDGF appears to be a poor therapeutic target, PDGFRalpha is particularly attractive because it can be activated by a much larger spectrum of vitreal growth factors than previously appreciated.
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Affiliation(s)
- Hetian Lei
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute, Boston, Massachusetts 02114, USA
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28
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Lei H, Kazlauskas A. Growth factors outside of the platelet-derived growth factor (PDGF) family employ reactive oxygen species/Src family kinases to activate PDGF receptor alpha and thereby promote proliferation and survival of cells. J Biol Chem 2009; 284:6329-36. [PMID: 19126548 PMCID: PMC2649107 DOI: 10.1074/jbc.m808426200] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 01/06/2009] [Indexed: 11/06/2022] Open
Abstract
The vitreous contains a plethora of growth factors that are strongly implicated in the formation of fibroproliferative diseases such as proliferative vitreoretinopathy. Although platelet-derived growth factors (PDGFs) are present in the vitreous, vitreal growth factors outside of the PDGF family activated the PDGF alpha receptor (PDGFRalpha) and promoted disease progression in a rabbit model of proliferative vitreoretinopathy (H. Lei, G. Velez, P. Hovland, T. Hirose, D. Gilbertson, and A. Kazlauskas (2008) submitted for publication.) In this report we investigated the mechanism by which non-PDGFs activated PDGFRalpha. We found that non-PDGFs increased the cellular level of reactive oxygen species (ROS) and that this event was necessary and sufficient for phosphorylation of PDGFRalpha. We speculated that the underlying mechanism was ROS-mediated inhibition of phosphotyrosine phosphatases, which antagonize receptor auto-phosphorylation. However, this did not appear to be the case. Non-PDGFs promoted tyrosine phosphorylation of catalytically inactive PDGFRalpha, and thereby indicated that at least one additional tyrosine kinase was involved. Indeed, preventing expression or blocking the kinase activity of Src family kinases suppressed non-PDGF-dependent tyrosine phosphorylation of PDGFRalpha. Thus non-PDGFs increased the level of ROS, which activated Src family kinases and resulted in phosphorylation of PDGFRalpha. Finally, although non-PDGFs induced only modest phosphorylation of PDGFRalpha, proliferation and survival of cells in response to non-PDGFs was significantly enhanced by expression of PDGFRalpha. These studies reveal a novel mechanism for activation of PDGFRalpha that appears capable of enhancing the responsiveness of cells to growth factors outside of the PDGF family.
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Affiliation(s)
- Hetian Lei
- Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
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29
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Russell MR, Jamieson WL, Dolloff NG, Fatatis A. The alpha-receptor for platelet-derived growth factor as a target for antibody-mediated inhibition of skeletal metastases from prostate cancer cells. Oncogene 2008; 28:412-21. [PMID: 18850002 DOI: 10.1038/onc.2008.390] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Bone resorption by osteoclasts is thought to promote the proliferation of prostate cancer cells disseminated to the skeleton (Mundy, 2002). Using a mouse model of experimental metastasis, we found that although late-stage metastatic tumors were indeed surrounded by osteoclasts, these cells were spatially unrelated to the small foci of cancer cells in early-stage metastases. This is the first evidence that survival and growth of disseminated prostate cancer cells immediately after their extravasation may not depend on osteoclast involvement. Interestingly, prostate cancer cells expressing the alpha-receptor for platelet-derived growth factor (PDGFRalpha) progress during early-stages of skeletal dissemination, whereas cells expressing lower levels or lacking this receptor fail to survive after extravasation in the bone marrow. However, non-metastatic cells acquire bone-metastatic potential upon ectopic overexpression of PDGFRalpha. Finally, functional blockade of human PDGFRalpha on prostate cancer cells utilizing a novel humanized monoclonal antibody -- soon to undergo phase-II clinical trials -- significantly impairs the establishment of early skeletal metastases. In conclusion, our results strongly implicate PDGFRalpha in prostate cancer bone tropism through its promotion of survival and progression of early-metastatic foci, providing ground for therapeutic strategies aimed at preventing or containing the initial progression of skeletal metastases in patients affected by prostate adenocarcinoma.
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Affiliation(s)
- M R Russell
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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