1
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Lee CS, Miao E, Das K, Seetharamu N. Clinical efficacy with dabrafenib and trametinib in a T599_V600insT poorly differentiated metastatic thyroid carcinoma. BMJ Case Rep 2021; 14:e243264. [PMID: 34413035 PMCID: PMC8378374 DOI: 10.1136/bcr-2021-243264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2021] [Indexed: 11/04/2022] Open
Abstract
BRAF (v-raf murine sarcoma viral oncogene homolog B1) and MEK (mitogen-activated protein kinase kinase) inhibitors have been shown to improve clinical outcomes in tumours presenting with mutations in the BRAF gene. The most common form of BRAF mutation is V600E/K and has been shown to occur in thyroid cancers. Treatment data for patients harbouring less frequent BRAF mutations are limited. In vitro studies have shown that mutations in codons 599-601 increase kinase activity similar to that in V600E mutations, which suggests that BRAF and MEK inhibitors could be an effective treatment option. Here, we report a case of a patient with thyroid carcinoma harbouring a rare amino acid insertion in codon 599 of the BRAF gene (T599_V600insT) treated with a BRAF and MEK inhibitor.
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Affiliation(s)
- Chung-Shien Lee
- Division of Medical Oncology and Hematology, Northwell Health Cancer Institute, Lake Success, New York, USA
- Clinical Health Professions, St John's University, Queens, New York, USA
| | - Emily Miao
- Pharmacy Department, North Shore University Hospital, Manhasset, New York, USA
| | - Kasturi Das
- Division of Cytopathology, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Greenvale, New York, USA
| | - Nagashree Seetharamu
- Division of Medical Oncology and Hematology, Northwell Health Cancer Institute, Lake Success, New York, USA
- Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
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2
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Luzón-Toro B, Fernández RM, Villalba-Benito L, Torroglosa A, Antiñolo G, Borrego S. Influencers on Thyroid Cancer Onset: Molecular Genetic Basis. Genes (Basel) 2019; 10:E913. [PMID: 31717449 PMCID: PMC6895808 DOI: 10.3390/genes10110913] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/25/2019] [Accepted: 11/06/2019] [Indexed: 02/07/2023] Open
Abstract
Thyroid cancer, a cancerous tumor or growth located within the thyroid gland, is the most common endocrine cancer. It is one of the few cancers whereby incidence rates have increased in recent years. It occurs in all age groups, from children through to seniors. Most studies are focused on dissecting its genetic basis, since our current knowledge of the genetic background of the different forms of thyroid cancer is far from complete, which poses a challenge for diagnosis and prognosis of the disease. In this review, we describe prevailing advances and update our understanding of the molecular genetics of thyroid cancer, focusing on the main genes related with the pathology, including the different noncoding RNAs associated with the disease.
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Affiliation(s)
- Berta Luzón-Toro
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain; (B.L.-T.); (R.M.F.); (L.V.-B.); (A.T.); (G.A.)
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 41013 Seville, Spain
| | - Raquel María Fernández
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain; (B.L.-T.); (R.M.F.); (L.V.-B.); (A.T.); (G.A.)
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 41013 Seville, Spain
| | - Leticia Villalba-Benito
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain; (B.L.-T.); (R.M.F.); (L.V.-B.); (A.T.); (G.A.)
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 41013 Seville, Spain
| | - Ana Torroglosa
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain; (B.L.-T.); (R.M.F.); (L.V.-B.); (A.T.); (G.A.)
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 41013 Seville, Spain
| | - Guillermo Antiñolo
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain; (B.L.-T.); (R.M.F.); (L.V.-B.); (A.T.); (G.A.)
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 41013 Seville, Spain
| | - Salud Borrego
- Department of Maternofetal Medicine, Genetics and Reproduction, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain; (B.L.-T.); (R.M.F.); (L.V.-B.); (A.T.); (G.A.)
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 41013 Seville, Spain
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3
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Melin A, Routier E, Tissot H, Rouleau E, Robert C. BRAF exon 11 mutant melanoma and sensitivity to BRAF/MEK inhibition: Two case reports. Eur J Cancer 2019; 121:109-112. [PMID: 31569065 DOI: 10.1016/j.ejca.2019.08.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/18/2019] [Accepted: 08/17/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Audrey Melin
- Department of Dermatology, Gustave Roussy, 114 Rue Edouard-Vaillant, 94800, Villejuif, France.
| | - Emilie Routier
- Department of Dermatology, Gustave Roussy, 114 Rue Edouard-Vaillant, 94800, Villejuif, France.
| | - Hubert Tissot
- Department of Nuclear Medicine, Gustave Roussy, 114 Rue Edouard-Vaillant, 94800, Villejuif, France.
| | - Etienne Rouleau
- Department of Medical Biology and Pathology, Gustave Roussy, 114 Rue Edouard-Vaillant, 94800, Villejuif, France.
| | - Caroline Robert
- Department of Dermatology, Gustave Roussy, 114 Rue Edouard-Vaillant, 94800, Villejuif, France; Paris-Sud University, 63 Rue Gabriel Péri, 94276, Le Kremlin-Bicêtre, France.
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4
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Londhe P, Gutwillig M, London C. Targeted Therapies in Veterinary Oncology. Vet Clin North Am Small Anim Pract 2019; 49:917-931. [PMID: 31186124 DOI: 10.1016/j.cvsm.2019.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Advances in molecular biology have permitted a much more detailed understanding of cellular dysfunction at the molecular and genetic levels in cancer cells. This has resulted in the identification of novel targets for therapeutic intervention, including proteins that regulate signal transduction, gene expression, and protein turnover. In many instances, small molecules are used to disrupt the function of these targets, often through competitive inhibition of ATP binding or the prevention of necessary protein-protein interactions. More than 40 small molecule inhibitors are now approved to treat a variety of human cancers, substantially impacting patient outcomes.
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Affiliation(s)
- Priya Londhe
- Tufts University School of Medicine, Boston, MA 02111, USA
| | - Megan Gutwillig
- Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Cheryl London
- Cummings School of Veterinary Medicine and School of Medicine, Tufts University, Jaharis Building, Room 814, 150 Harrison Avenue, Boston, MA 0211, USA.
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5
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Trubini S, Ubiali A, Paties CT, Cavanna L. Novel BRAF mutation in melanoma: A case report. Mol Clin Oncol 2018; 8:460-462. [PMID: 29456854 DOI: 10.3892/mco.2018.1555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 11/17/2017] [Indexed: 11/05/2022] Open
Abstract
In melanoma, a number of specific genetic and genomic aberrations have been identified to be important in tumorigenesis. In particular, the mutant B-Raf proto-oncogene, Serine/Threonine kinase (BRAF) gene is the target of tailored therapy with kinase inhibitor molecules. Identification of the array of mutations in patients with melanoma will be useful in determining a genetic profile of the tumor with potential implications for treatment decisions. A rare aminoacidic insertion in codon 599 of the BRAF gene (c.1797_1798insACA, T599insT) was detected by using both direct (Sanger) sequencing and pyrosequencing techniques in a metastatic melanoma of a female elderly patient. As suggested in other clinical contexts including pilocytic astrocytoma, papillary thyroid carcinomas and anaplastic thyroid carcinomas, this unusual mutation may be associated with a modified spatial structure of activated P-loop, resulting in a constitutional activation of the BRAF protein. The patient died shortly following the test, thus no biological therapy was performed. Comparable data regarding treatment of melanoma patients with rare BRAF mutations is lacking, and the response to BRAF inhibitors requires further investigation.
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Affiliation(s)
- Serena Trubini
- Onco-Hematologic Department, Ospedale Guglielmo da Saliceto, I-49-29121 Piacenza, Italy
| | - Alessandro Ubiali
- Onco-Hematologic Department, Ospedale Guglielmo da Saliceto, I-49-29121 Piacenza, Italy
| | - Carlo Terenzio Paties
- Onco-Hematologic Department, Ospedale Guglielmo da Saliceto, I-49-29121 Piacenza, Italy
| | - Luigi Cavanna
- Onco-Hematologic Department, Ospedale Guglielmo da Saliceto, I-49-29121 Piacenza, Italy
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Abstract
There has been a steady incorporation of powerful new molecular tools into the evaluation and management of thyroid nodules and thyroid cancer. With an increasing incidence of nodules and differentiated thyroid cancer (DTC) being diagnosed in children and adolescents, oncogene data are providing insight into the clinical differences between pediatric and adult patients with histologically similar DTC. However, additional investment and efforts are needed to define the genomic landscape for pediatric DTC with the goal of improving preoperative diagnostic accuracy as well as stratifying treatment in an effort to reduce complications of therapy.
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Affiliation(s)
- Andrew J Bauer
- Division of Endocrinology and Diabetes, The Thyroid Center, The Children's Hospital of Philadelphia, The Perelman School of Medicine, The University of Pennsylvania, 3401 Civic Center Boulevard, Philadelphia, PA 19104, USA.
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7
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Syrenicz A, Koziołek M, Ciechanowicz A, Sieradzka A, Bińczak-Kuleta A, Parczewski M. New insights into the diagnosis of nodular goiter. Thyroid Res 2014; 7:6. [PMID: 24987460 PMCID: PMC4076755 DOI: 10.1186/1756-6614-7-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/21/2014] [Indexed: 11/10/2022] Open
Abstract
Preoperative diagnostic investigations of nodular goiter are based on two main examinations: ultrasonography of the thyroid gland and ultrasound-guided fine-needle aspiration biopsy. So far, FNAB has been the best method for the differentiation of nodules, but in some cases it fails to produce a conclusive diagnosis. Some of the biopsies do not provide enough material to establish the diagnosis, in some other biopsies cytological picture is inconclusive. Determining the eligibility of thyroid focal lesions for surgery has been more and more often done with molecular methods. The most common genetic changes leading to the development of thyroid cancer include mutations, translocations and amplifications of genes, disturbances in gene methylation and dysregulation of microRNA. The mutations of Ras proto-oncogenes and BRAF gene as well as disturbances of DNA methylation in promoter regions of genes regulating cell cycle (e.g. hypermethylation of RASSF1A gene and TIMP-3 gene) play an important role in the process of neoplastic transformation of thyreocyte. The advances in molecular biology made it possible to investigate these genetic disturbances in DNA and/or RNA from peripheral blood, postoperative thyroid tissue material and cytology specimens obtained through fine-needle aspiration biopsy of focal lesions in the thyroid gland. As it became possible to analyze the mutations and methylation of genes from cell material obtained through fine-needle aspiration biopsy, it would be beneficial to introduce the techniques of molecular biology in the pre-operative diagnosis of nodular goiter as a valuable method, complementary to ultrasonography and FNAB. The knowledge obtained from molecular studies might help to determine the frequency of follow-up investigations in patients with nodular goiter and to select patients potentially at risk of developing thyroid cancer, which would facilitate their qualification for earlier strumectomy.
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Affiliation(s)
- Anhelli Syrenicz
- Department of Endocrinology, Metabolic Diseases and Internal Diseases, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Monika Koziołek
- Department of Endocrinology, Metabolic Diseases and Internal Diseases, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Andrzej Ciechanowicz
- Department of Laboratory Diagnostics and Molecular Medicine, Pomeranian Medical University, Szczecin, Poland
| | - Anna Sieradzka
- Department of Endocrinology, Metabolic Diseases and Internal Diseases, Pomeranian Medical University in Szczecin, Szczecin, Poland
| | - Agnieszka Bińczak-Kuleta
- Department of Laboratory Diagnostics and Molecular Medicine, Pomeranian Medical University, Szczecin, Poland
| | - Miłosz Parczewski
- Department of Infectious Diseases and Hepatology, Pomeranian Medical University, Szczecin, Poland
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8
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Abstract
With recent advances in molecular biology, abnormalities in cancer cells that contribute to dysregulation of cell survival and proliferation are being characterized with greater precision. Through this process, key abnormalities in cancer cells involving proteins that regulate signal transduction, migration, mitosis and other critical processes have been identified. Such abnormalities often involve a class of proteins called kinases that act to phosphorylate other proteins in the cell, resulting in activation of these proteins in the absence of appropriate stimulation/regulation. Given their role in tumour biology, substantial effort has been directed at blocking the function of these proteins. Several approaches have been used, including monoclonal antibodies and small molecule inhibitors. While antibodies are primarily directed at cell surface proteins, small molecule inhibitors, also known as kinase inhibitors, target proteins throughout the cell. A variety of kinase inhibitors have been approved for the treatment of human cancers. In some instances, these inhibitors have exhibited significant clinical efficacy, and it is likely that their biological activity will be further enhanced as combination regimens with standard treatment modalities are explored. The use of kinase inhibitors in dogs and cats is relatively recent, although two inhibitors, toceranib (Palladia; Pfizer Animal Health, Madison, NJ, USA) and masitinib (Kinavet; Catalent Pharma Solutions, Somerset, NJ, USA) have been approved by the Federal Drug Administration (USA) for use in dogs. This article reviews the biology of protein kinase dysfunction in human and animal cancers, and the application of specific kinase inhibitors to veterinary cancer patients.
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Affiliation(s)
- Cheryl A London
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43214, USA.
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9
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Kim YS, Kim JS, Bae JS, Park WC. Clinical implication of the BRAFV600E mutation in papillary thyroid carcinoma. World J Surg Oncol 2013; 11:99. [PMID: 23687957 PMCID: PMC3660263 DOI: 10.1186/1477-7819-11-99] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 05/12/2013] [Indexed: 01/22/2023] Open
Abstract
Background The BRAFV600E mutation is the most common genetic alteration in papillary thyroid carcinoma (PTC). In recent studies, the BRAFV600E mutation has been associated with poor clinicopathological characteristics, such as lymph node metastasis, extrathyroidal extension, and advanced stage. However, other studies have failed to establish an association between the BRAFV600E mutation and clinicopathological features. Therefore, we investigated the relationship between the BRAFV600E mutation and its clinicopathological factors at a single institution. Methods A total of 327 consecutive patients with PTC were enrolled in this study and underwent thyroid surgery at Yeouido St. Mary’s Hospital between February 2010 and December 2011. BRAFV600E mutation analysis was performed using polymerase chain reaction (PCR)-based amplification of DNA extracted from paraffin-embedded tumour specimens. Results The BRAFV600E mutation was detected in the tumours of 241 (73.7%) patients. Lymph node metastasis, TNM stage, and multifocality were not significantly associated with the BRAFV600E mutation. However, larger tumour size, extrathyroidal extension, histologic type (classic type), and concurrent Hashimoto’s thyroiditis were associated with the BRAFV600E mutation in the univariate analysis, although no clinicopathological features were associated with the BRAFV600E mutation in the multivariate analysis. Conclusion There was no idependent prognostic factor associated with BRAFV600E mutation status in this study. The BRAFV600E mutation is unlikely to serve as a prognostic factor for PTC.
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Affiliation(s)
- Yong-Seok Kim
- Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
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10
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Leonardi GC, Candido S, Carbone M, Raiti F, Colaianni V, Garozzo S, Cinà D, McCubrey JA, Libra M. BRAF mutations in papillary thyroid carcinoma and emerging targeted therapies (review). Mol Med Rep 2012; 6:687-94. [PMID: 22858857 DOI: 10.3892/mmr.2012.1016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 05/21/2012] [Indexed: 11/05/2022] Open
Abstract
Papillary thyroid carcinoma (PTC) is the most common histotype among the thyroid cancer types. Although PTC is a curable malignancy, many patients relapse after treatment. Thus, there is a need to identify novel factors involved in the pathogenesis of PTC that may be used as targets for new therapies. The MAPK pathway has been implicated in the pathogenesis of PTC. Therefore, in this review, we summarize the role of the BRAF V600E mutation in the development and progression of thyroid cancer. The cinical implication of this molecular abnormality is also discussed. It is evident that the detection of the BRAF V600E mutation is crucial in order to identify novel avenues for thyroid cancer treatment.
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Affiliation(s)
- Giulia Costanza Leonardi
- Department of Biomedical Sciences, Laboratory of Translational Oncology and Functional Genomics, University of Catania, Catania, Italy
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11
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Bauer AJ, Francis GL. Update on the molecular signature of differentiated thyroid cancer: clinical implications and potential opportunities. Expert Rev Endocrinol Metab 2011; 6:819-834. [PMID: 30780870 DOI: 10.1586/eem.11.68] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
With the development and maturation of new technologies, there has been a steady incorporation of powerful new tools into the evaluation and management of thyroid nodules and thyroid cancer. An increasing number of reports on oncogene testing and molecular screening in fine-needle aspiration biopsy samples have been published. However, there remains a paucity of data and consensus on combining both conventional and molecular technologies to determine the diagnosis and/or prognosis of disease. All patients with differentiated thyroid cancer stand to benefit from the identification and incorporation of reliable molecular markers into clinical practice. Identification of reliable markers would allow for stratification of treatment, affording the medical and surgical teams an ability to individually tailor evaluation and treatment, applying aggressive therapy and monitoring only when clinically warranted. For the majority of patients with thyroid cancer, the incorporation of a validated, multifaceted molecular profiling system may not improve survival; however, there is great opportunity for these efforts to decrease the morbidity associated with our current approach.
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Affiliation(s)
- Andrew J Bauer
- a Pediatric Endocrinology, Department of Pediatrics, Walter Reed Army Medical Center, Washington, DC, USA.
- b Uniformed Services University, Bethesda, MD, USA
- c Thyroid Center, Division of Endocrinology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Gary L Francis
- d Division of Endocrinology, Department of Pediatrics, Children's Hospital of Richmond at The Commonwealth University Health System, Medical College of Virginia, Richmond, VA, USA
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12
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Nucera C, Lawler J, Parangi S. BRAF(V600E) and microenvironment in thyroid cancer: a functional link to drive cancer progression. Cancer Res 2011; 71:2417-22. [PMID: 21447745 DOI: 10.1158/0008-5472.can-10-3844] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Papillary thyroid cancer (PTC) rates continue to increase in the United States and Europe, and, although most patients do well, some recur and die of their disease. Patients with PTC harboring the BRAF(V600E) mutation seem to display a more aggressive clinical behavior, but little is known about the role of this mutation in crucial processes in the tumor microenvironment, such as tumor adhesion, migration, invasion, and metastasis. The extracellular matrix (ECM) microenvironment is not merely a structural scaffold for the cellular elements of the epithelial and stromal microenvironment, but it also elicits a profound influence on cell behavior affecting viability, proliferation, adhesion, and motility. The effects of BRAF(V600E) on cell surface receptors (i.e., integrins) and ECM noncellular components [i.e., thrombospondin-1 (TSP-1) and fibronectin (FN)] seem to trigger different pathologic biological processes in a cell context-dependent manner. This review focuses on the recent progress in understanding the role of BRAF(V600E) in the regulation of some ECM noncellular components and trans-membrane receptors of the microenvironment in PTC in order to design novel targeted therapies directed at the BRAF(V600E) multifaceted signaling cascades. Some of these targeted therapeutics, such as ATP-competitive BRAF(V600E) inhibitors (i.e., orally bioavailable PLX4720 and PLX4032 compounds), are already under investigation.
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Affiliation(s)
- Carmelo Nucera
- Thyroid Cancer Research Laboratory, Endocrine Surgery Unit, Massachusetts General Hospital, Harvard Medical School, and Division of Cancer Biology and Angiogenesis, Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
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13
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Buckmelter AJ, Ren L, Laird ER, Rast B, Miknis G, Wenglowsky S, Schlachter S, Welch M, Tarlton E, Grina J, Lyssikatos J, Brandhuber BJ, Morales T, Randolph N, Vigers G, Martinson M, Callejo M. The Discovery of furo[2,3-c]pyridine-based indanone oximes as potent and selective B-Raf inhibitors. Bioorg Med Chem Lett 2011; 21:1248-52. [DOI: 10.1016/j.bmcl.2010.12.039] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/02/2010] [Accepted: 12/06/2010] [Indexed: 11/24/2022]
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Abstract
Although neuroendocrine tumors are rare, the more common types such as gastrointestinal and pancreatic carcinoids, medullary thyroid cancers, and small cell lung cancers have been studied in detail during the last few years. Data published thus far indicate that multiple signaling pathways are involved in these cancers. Recent focus has been on developing novel therapeutics by targeting specific signaling pathways. This article details several of the signaling mechanisms that have been discovered to play a role in the development and progression of neuroendocrine tumors. The therapeutic options developed to address the various pathways, including their specific mechanisms of actions, are also discussed.
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Affiliation(s)
- Barbara Zarebczan
- Endocrine Surgery Research Laboratories, Department of Surgery, University of Wisconsin Carbone Cancer Center, Madison, WI 53705, USA
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15
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Rauch J, O'Neill E, Mack B, Matthias C, Munz M, Kolch W, Gires O. Heterogeneous nuclear ribonucleoprotein H blocks MST2-mediated apoptosis in cancer cells by regulating A-Raf transcription. Cancer Res 2010; 70:1679-88. [PMID: 20145135 DOI: 10.1158/0008-5472.can-09-2740] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A-Raf belongs to the family of oncogenic Raf kinases that are involved in mitogenic signaling by activating the mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK)-ERK pathway. Low kinase activity of A-Raf toward MEK suggested that A-Raf might have alternative functions. Here, we show that A-Raf prevents cancer cell apoptosis contingent on the expression of the heterogeneous nuclear ribonucleoprotein H (hnRNP H) splice factor, which is required for the correct transcription and expression of a-raf. Apoptosis was prevented by A-Raf through sequestration and inactivation of the proapoptotic MST2 kinase. Small interfering RNA-mediated knockdown of hnRNP H or A-Raf resulted in MST2-dependent apoptosis. In contrast, enforced expression of either hnRNP H or A-Raf partially counteracted apoptosis induced by etoposide. In vivo expression studies of colon specimens corroborated the overexpression of hnRNP H in malignant tissues and its correlation with A-Raf levels. Our findings define a novel mechanism that is usurped in tumor cells to escape naturally imposed apoptotic signals.
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Affiliation(s)
- Jens Rauch
- Department of Head and Neck Research, Ludwig-Maximilians-Universität München, D-81377 Munich, Germany
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16
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Abstract
Although fine-needle aspiration biopsy (FNA) remains the mainstay of the preoperative workup of thyroid nodules, it does not provide a diagnosis in up to 20% of nodules. This group of indeterminate lesions, including lesions with cellular atypia, suspicious cytology, and demonstrating a follicular pattern, provides one of the greatest challenges to researchers in thyroid cancer today. Over the last 2 decades, considerable work has been done to find molecular markers to resolve this diagnostic dilemma. This article explores some of the markers including galectin-3, HBME-1, BRAF, RET/PTC, PAX8-PPARgamma, hTERT, telomerase, miRNA, and microarray and multigene assays. Although no one marker has proven to be a panacea, several combinations of markers have shown great promise as an adjunct to FNA.
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Affiliation(s)
- Meredith A Kato
- Division of Endocrine Surgery, Department of Surgery, New York Presbyterian Hospital, Weill Cornell Medical Center, New York, NY 10068, USA.
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17
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Oikonomou E, Makrodouli E, Evagelidou M, Joyce T, Probert L, Pintzas A. BRAF(V600E) efficient transformation and induction of microsatellite instability versus KRAS(G12V) induction of senescence markers in human colon cancer cells. Neoplasia 2009; 11:1116-31. [PMID: 19881948 PMCID: PMC2767214 DOI: 10.1593/neo.09514] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Revised: 07/24/2009] [Accepted: 07/28/2009] [Indexed: 12/30/2022]
Abstract
In colorectal cancer, BRAF and KRAS oncogenes are mutated in about 15% and 35% respectively at approximately the same stage of the adenoma-carcinoma sequence. Since these two mutations rarely coexist, further analysis to dissect their function of transformation in colon cancer is required. Caco-2 human colon adenocarcinoma cells were stably transfected with BRAF(V600E) (Caco-BR cells) or KRAS(G12V) (Caco-K cells) oncogenes. BRAF(V600E) is more efficient in transforming Caco-2 cells and altering their morphology. The dominant nature of BRAF(V600E) is evident by its ability to render Caco-2 cells tumorigenic in vivo all be it through selective extracellular signal-related kinase (ERK) 2 phosphorylation and high levels of cyclin D1. As a consequence, the cell cycle distribution of parental cells is altered and microsatellite instability is introduced. Attenuated ERK activation observed correlated with KSR downregulation by BRAF(V600E) without further implications to signaling. Highly activated ERK in case of KRAS(G12V) (Caco-K cells) leads to mild transformation causing Caco-K cells to express premature senescence-related markers and acquire growth factor-dependent viability. Interestingly, BRAF(WT)gets equally activated by upstream KRAS mutations present in colon adenocarcinoma cells such as DLD-1 and SW620. Taken together, these results suggest that the two oncogenes have different transforming capability in colon cancer, although they both use the mitogen-activated protein (MAP) kinase pathway to carry out their effect. In general, BRAF(V600E) presents greater potential in mediating tumorigenic effect as compared to KRAS(G12V) both in vivo and in vitro. These findings may have implications in personalised diagnosis and targeted therapeutics.
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Affiliation(s)
- Eftychia Oikonomou
- Laboratory of Signal Mediated Gene Expression, Institute of Biological Research and Biotechnology , National Hellenic Research Foundation, Athens, Greece
| | - Eleni Makrodouli
- Laboratory of Signal Mediated Gene Expression, Institute of Biological Research and Biotechnology , National Hellenic Research Foundation, Athens, Greece
| | - Maria Evagelidou
- Laboratory of Molecular Genetics, Hellenic Pasteur Institute, Athens, Greece
| | - Tobias Joyce
- Laboratory of Signal Mediated Gene Expression, Institute of Biological Research and Biotechnology , National Hellenic Research Foundation, Athens, Greece
| | - Lesley Probert
- Laboratory of Molecular Genetics, Hellenic Pasteur Institute, Athens, Greece
| | - Alexander Pintzas
- Laboratory of Signal Mediated Gene Expression, Institute of Biological Research and Biotechnology , National Hellenic Research Foundation, Athens, Greece
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Schultz J, Ibrahim SM, Vera J, Kunz M. 14-3-3sigma gene silencing during melanoma progression and its role in cell cycle control and cellular senescence. Mol Cancer 2009; 8:53. [PMID: 19642975 PMCID: PMC2723074 DOI: 10.1186/1476-4598-8-53] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2009] [Accepted: 07/30/2009] [Indexed: 12/19/2022] Open
Abstract
Background The family of 14-3-3 proteins plays an important role in cancer biology by interfering with intracellular signalling pathways and cell cycle checkpoints. The 14-3-3σ isoform acts as a tumor suppressor and is often inactivated during tumor development. Results Here, we demonstrate enhanced CpG methylation of the 14-3-3σ gene in lymph node and cutaneous melanoma metastases compared with primary tumors, associated with dramatically reduced mRNA expression. In line with this, treatment of different metastatic melanoma cell lines with 5-aza-2'-deoxycytidine (5-Aza-CdR), a potent inhibitor of cytosine methylation, significantly induces 14-3-3σ protein expression. Additional treatment with histone deacetylase inhibitor 4-phenylbutyric acid (Pba) further enhances 14-3-3σ expression. Induction of 14-3-3σ expression by 5-Aza-CdR/Pba treatment leads to almost complete inhibition of cell proliferation, with cells predominantly arrested in G2-M. The antiproliferative effect of 5-Aza-CdR/Pba was reversed in 14-3-3σ knockdown cells. Similarly, melanoma cell lines stably overexpressing 14-3-3σ show dramatically reduced cell proliferation rates. Moreover, synchronous 14-3-3σ stably overexpressing cells do not progress through cell cycle, but display a permanent increase in the population of 4n DNA containing cells. Interestingly, overexpression of 14-3-3σ induces senescence of melanoma cells and is involved in melanoma cell senescence under genotoxic stress. Finally, 14-3-3σ knockdown supports migratory capacity of melanoma cells in vitro, while 14-3-3σ overexpression has opposing effects. Conclusion Taken together, the present report indicates that epigenetic silencing of 14-3-3σ might contribute to tumor progression in malignant melanoma via loss of cell cycle control, impaired cellular senescence program and support of migratory capacity.
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Affiliation(s)
- Julia Schultz
- Department of Cardiac Surgery, University of Rostock, Rostock, Germany.
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Vía de señalización dependiente de la proteincinasa de activación mitogénica en el carcinoma papilar de tiroides. De las bases moleculares a la práctica clínica. ACTA ACUST UNITED AC 2009; 56:176-86. [DOI: 10.1016/s1575-0922(09)70982-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 03/18/2009] [Indexed: 11/23/2022]
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Oncogenic activation of MAP kinase by BRAF pseudogene in thyroid tumors. Neoplasia 2009; 11:57-65. [PMID: 19107232 DOI: 10.1593/neo.81044] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/12/2008] [Accepted: 10/14/2008] [Indexed: 11/18/2022] Open
Abstract
Activating BRAF mutations have been reported in 40% of papillary thyroid carcinomas (PTCs). The involvement of BRAF pseudogene in thyroid tumorigenesis has not previously been studied. We investigated BRAF pseudogene expression in 68 thyroid tumors: 16 multinodular goiters, 43 classic PTCs, 6 follicular variants of PTC, and 3 anaplastic thyroid carcinomas. BRAF pseudogene function was studied by Western blots, soft agar assay, and tumorigenesis in nude mice. BRAF pseudogene expression was detected in 7 multinodular goiters, 18 classic PTC, and 1 follicular variants of PTC. There is an inverse correlation between BRAF pseudogene expression and BRAF mutation. The pseudogene transcripts were more frequently detected in tumors without BRAF mutation than those with BRAF mutation. Furthermore, BRAF pseudogene expression could activate the MAP kinase signaling pathway, transform NIH3T3 cells in vitro, and induce tumors in nude mice. These data suggest that BRAF pseudogene activation may play a role in thyroid tumor development.
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Nucera C, Goldfarb M, Hodin R, Parangi S. Role of B-Raf(V600E) in differentiated thyroid cancer and preclinical validation of compounds against B-Raf(V600E). Biochim Biophys Acta Rev Cancer 2009; 1795:152-61. [PMID: 19356676 DOI: 10.1016/j.bbcan.2009.01.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 01/15/2009] [Accepted: 01/18/2009] [Indexed: 10/21/2022]
Abstract
B-Raf(V600E), an oncogenic protein kinase, is the most frequent genetic alteration in papillary thyroid carcinomas (PTC). PTC represents 80-90% of all thyroid cancers and over the past five years, more than 200 manuscripts have been published about the relationship between "B-Raf(V600E) and thyroid cancer". B-Raf(V600E) genetically arises from a transversion point mutation (valine-to-glutamate substitution at amino acid residue-600, V600E) and leads to over activation of the mitogen-activated protein kinases (MAPK) signaling pathway. The MAPK pathway is essential for transmitting proliferation signals generated by cell surface receptors and cytoplasmic signaling elements to the nucleus. In many cancers, including thyroid cancer, B-Raf(V600E) appears to play a crucial role in cell proliferation, survival and de-differentiation. In thyroid cancer, the V600E mutation occurs with greater frequently in aggressive subtypes of PTC, and in individuals that present at advanced stages of disease with extra-thyroidal extension and/or lymph node metastases. B-Raf(V600E) is considered a marker of aggressive disease in both PTC (>1 cm) and micro-PTC (</=1 cm), and interestingly, is associated with both loss of I-131 avidity and PTC recurrence. Though treatment of patients with thyroid cancer is usually successful and most patients are rendered disease-free, to date there are no effective therapies for patients with invasive, non-radioiodine sensitive tumors or metastatic disease. In this article we will review the relation between B-Raf(V600E) and PTC, as well as both non-selective and selective pharmacological agents currently under investigation for treatment of B-Raf(V600E) positive PTC.
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Affiliation(s)
- Carmelo Nucera
- Endocrine Surgery Department, Thyroid Cancer Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Division of General and Gastrointestinal Surgery, Wang ACC 460, 15 Parkman Street, Boston, MA 02115, USA
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Schultz J, Lorenz P, Ibrahim SM, Kundt G, Gross G, Kunz M. The functional −443T/C osteopontin promoter polymorphism influences osteopontin gene expression in melanoma cells via binding of c-Myb transcription factor. Mol Carcinog 2009; 48:14-23. [DOI: 10.1002/mc.20452] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Abstract
There is now a reasonably good understanding of the key oncogenic events involved in the initiation and progression of thyroid cancer. Many of these are characteristic of certain tumor types, and their presence conveys diagnostic and prognostic information. It is not yet clear how this information will be applied to clinical practice. Based on preclinical evidence, mutations of genes encoding certain kinases may also predict response to specific tyrosine kinase inhibitors, although this has not yet been explored systematically in clinical trials.
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Affiliation(s)
- James A Fagin
- Department of Medicine and Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA.
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Baitei EY, Zou M, Al-Mohanna F, Collison K, Alzahrani AS, Farid NR, Meyer B, Shi Y. Aberrant BRAF
splicing as an alternative mechanism for oncogenic B-Raf activation in thyroid carcinoma. J Pathol 2008; 217:707-15. [DOI: 10.1002/path.2496] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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25
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Hansen TE, Puntervoll P, Seternes OM, Jørgensen JB. Atlantic salmon possess three mitogen activated protein kinase kinase 6 paralogs responding differently to stress. FEBS J 2008; 275:4887-902. [DOI: 10.1111/j.1742-4658.2008.06628.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Barzon L, Masi G, Boschin IM, Lavezzo E, Pacenti M, Casal Ide E, Toniato A, Toppo S, Palù G, Pelizzo MR. Characterization of a novel complex BRAF mutation in a follicular variant papillary thyroid carcinoma. Eur J Endocrinol 2008; 159:77-80. [PMID: 18426810 DOI: 10.1530/eje-08-0239] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Activating mutations of the BRAF oncogene are frequently detected in papillary thyroid carcinoma (PTC) and have been associated with a worse prognosis. The amino acid substitution V600E accounts for 90% of all oncogenic BRAF mutations and is typically detected in classic PTCs, whereas other less frequent BRAF mutations seem to be associated with other PTC histotypes. CASE Screening for activating BRAF mutations in a series of 83 PTCs identified the most common V600E mutation in 39 cases (histologically, 38 classic PTCs and 1 sclerosing variant PTC) and a complex in-frame mutation involving amino acids V600-S605 in a stage III multicentric follicular variant PTC, occurring in a 50-year-old female patient, who was affected by hypothyroidism in autoimmune thyroiditis and had a family history of PTC and autoimmune thyroiditis. Since the identified BRAF mutation was novel in the literature, bioinformatic modeling was performed to predict its impact on BRAF activity. Although the mutation resulted in loss of a phosphorylation site in the activation loop of BRAF, it was predicted to increase BRAF kinase activity by mimicking an activating phosphorylation. CONCLUSIONS This study, which reports a new BRAF mutation, highlights the usefulness of bioinformatic modeling in the prediction of functional effects of new mutations and indicates that mutation-specific screening tests might miss some rare BRAF mutations. These facts should be taken into consideration in the molecular diagnosis of thyroid cancer and in the design of therapeutic protocols based on inhibitors of the BRAF pathway.
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Affiliation(s)
- Luisa Barzon
- Department of Histology, Microbiology, and Medical Biotechnologies, University of Padova, I-35121 Padova, Italy
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Pizzolanti G, Russo L, Richiusa P, Bronte V, Nuara RB, Rodolico V, Amato MC, Smeraldi L, Sisto PS, Nucera M, Bommarito A, Citarrella R, Lo Coco R, Cabibi D, Lo Coco A, Frasca F, Gulotta G, Latteri MA, Modica G, Galluzzo A, Giordano C. Fine-needle aspiration molecular analysis for the diagnosis of papillary thyroid carcinoma through BRAF V600E mutation and RET/PTC rearrangement. Thyroid 2007; 17:1109-15. [PMID: 17727338 DOI: 10.1089/thy.2007.0008] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE To evaluate BRAF(V600E) mutation on consecutive fine-needle aspiration biopsy (FNAB) specimens in order to assess FNAB's usefulness in preoperative papillary thyroid carcinoma (PTC) diagnosis with the contemporaneous analysis of RET/PTC1 and RET/PTC3 rearrangements obtained from ex vivo thyroid nodules. DESIGN Thyroid FNABs from 156 subjects with nodules and 49 corresponding surgical samples were examined for the presence of BRAF mutation by real-time allele-specific polymerase chain reaction, confirmed with the use of a laser pressure catapulting system. Samples were also examined for RET/PTC rearrangements. The results were compared with the cytological diagnosis and histopathology. MAIN OUTCOMES 13/156 cytological examinations were diagnostic for PTC and 19/156 showed suspicious/indeterminate FNAB (12.2%). FNAB-BRAF(V600E) mutation was detected in 11/16 (69%) cases with histological confirmation of PTC. In our series, RET/PTC rearrangement was detected in only one case of PTC, whereas it was not present in any case of adenoma, goiter, or Hashimoto's thyroiditis. No PTC case was found positive at the same time for BRAF mutation and RET/PTC rearrangements. CONCLUSION BRAF(V600E) mutation detected on FNAB specimens, more than RET/PTC rearrangements, is highly specific for PTC and its routine research might well be an adjunctive and integrative diagnostic tool for the preoperative diagnostic iter.
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Affiliation(s)
- Giuseppe Pizzolanti
- Endocrinology Section, Department of Experimental Oncology and Clinical Applications, University of Palermo, Piazza del Cliniche 2, Palermo, Italy
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London CA. The role of small molecule inhibitors for veterinary patients. Vet Clin North Am Small Anim Pract 2007; 37:1121-36; vii. [PMID: 17950886 DOI: 10.1016/j.cvsm.2007.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Advances in molecular biology over the past several years have permitted a much more detailed understanding of cellular dysfunction at the biochemical level in cancer cells. This has resulted in the identification of novel targets for therapeutic intervention, including proteins that regulate signal transduction, gene expression, and protein turnover. In many instances, small molecules are used to disrupt the function of these targets, often through competitive inhibition of ATP binding or the prevention of necessary protein-protein interactions. Future challenges lie in identifying appropriate targets for intervention and combining small molecule inhibitors with standard treatment modalities, such as radiation therapy and chemotherapy.
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Affiliation(s)
- Cheryl A London
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 454 VMAB, 1925 Coffey Road, Columbus, OH 43210, USA.
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Abstract
BRAF somatic mutations are frequently found in primary and metastatic melanomas and melanocytic naevi. Commonly found BRAF mutants stimulate constitutive RAF/MEK (mitogen-activated ERK-activating kinase)/ERK (extracellular signal-regulated kinase) pathway activation and act as transforming oncogenes in NIH-3T3 cells and immortalized murine melanocytes. The most common BRAF mutation is the V600E alteration, but over 30 distinct BRAF mutations, varying in biological activity, have been found and may be predictive of clinically relevant tumour differences. The origin of these acquired mutations remains unknown, but melanomas have a different BRAF mutational spectrum from other tumours, possibly resulting from unique environmental exposures. In melanoma cases, BRAF mutations are frequently found in superficial spreading or nodular histological subtypes, in tumours on intermittently sun-exposed sites and in younger patients. Although evidence indicates that the activation of the RAF/MEK/ERK pathway influences the proliferation, invasion and survival of melanoma cells in vitro, the exact role of BRAF mutation in melanoma tumour progression, maintenance and outcome remains controversial. In addition, although BRAF and NRAS mutations are mutually exclusive in melanomas, other genetic events may complement BRAF mutation to produce biological activity similar to NRAS mutation. Nonetheless, preclinical and early clinical studies predict that RAF/MEK/ERK pathway inhibitors will have therapeutic activity towards melanoma, but that tumour subclassification by BRAF/NRAS mutational status may be necessary to evaluate their efficacy.
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Affiliation(s)
- Nancy E Thomas
- Department of Dermatology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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Kunnimalaiyaan M, Chen H. The Raf-1 pathway: a molecular target for treatment of select neuroendocrine tumors? Anticancer Drugs 2006; 17:139-42. [PMID: 16428931 DOI: 10.1097/00001813-200602000-00004] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neuroendocrine (NE) tumors such as medullary thyroid cancer, carcinoid, small cell lung cancer and pheochromocytoma are metastatic in nature, and secrete biogenic amines and hormones. In this review, we will discuss the possibility that activation of the Ras/Raf signaling pathway may be a therapeutic target for patients with select NE tumors. In-vitro activation of Raf-1 in NE tumors either by expression of the ectopic catalytic domain of Raf-1 or by a pharmacologic drug, ZM336372, resulted in growth inhibition. In addition, activation of the Ras/Raf pathway led to a significant reduction in NE markers such as serotonin, chromogranin A and calcitonin. These data support development of Raf-1-activating compounds for treatment of patients with NE tumors of selective subtypes.
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Williams JP, Stewart T, Li B, Mulloy R, Dimova D, Classon M. The retinoblastoma protein is required for Ras-induced oncogenic transformation. Mol Cell Biol 2006; 26:1170-82. [PMID: 16449633 PMCID: PMC1367176 DOI: 10.1128/mcb.26.4.1170-1182.2006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Revised: 05/23/2005] [Accepted: 10/20/2005] [Indexed: 12/24/2022] Open
Abstract
Most human cancers involve either mutational activation of the Ras oncogenic pathway and/or inactivation of the retinoblastoma tumor suppressor (RB) pathway. Paradoxically, tumors that harbor Ras mutations almost invariably retain expression of a wild-type pRB protein. We explain this phenomenon by demonstrating that Ras-induced oncogenic transformation surprisingly depends on functional pRB protein. Cells lacking pRB are less susceptible to the oncogenic actions of H-RasV12 than wild-type cells and activated Ras has an inhibitory effect on the proliferation of pRB-deficient human tumor cells. In addition, depletion of pRB from Ras-transformed murine cells or human tumor cells that harbor Ras pathway mutations inhibits their proliferation and anchorage-independent growth. In sharp contrast to pRB-/- 3T3 cells, fibroblasts deficient in other pRB family members (p107 and p130) are more susceptible to Ras-mediated transformation than wild-type 3T3 cells. Moreover, loss of pRB in tumor cells harboring a Ras mutation results in increased expression of p107, and overexpression of p107 but not pRB strongly inhibits proliferation of these tumor cells. Together, these findings suggest that pRB and p107 have distinct roles in Ras-mediated transformation and suggest a novel tumor-suppressive role for p107 in the context of activated Ras.
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Affiliation(s)
- Jonathan P Williams
- MGH Cancer Center and Harvard Medical School, Bldg. 149, 13th St., Charlestown, MA 02129, USA
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Shelly S, Chien MB, Yip B, Kent MS, Theon AP, McCallan JL, London CA. Exon 15 BRAF mutations are uncommon in canine oral malignant melanomas. Mamm Genome 2005; 16:211-7. [PMID: 15834638 DOI: 10.1007/s00335-004-2441-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Accepted: 11/05/2004] [Indexed: 10/25/2022]
Abstract
An activating mutation in codon 599 of BRAF has been identified in approximately 60% of human cutaneous nevi and melanomas, but not melanomas of mucosal origin. The purpose of this study was to determine if BRAF mutations occur in canine oral malignant melanomas. The canine BRAF gene was first cloned from normal canine testicular cDNA, and a novel previously unreported splice variant involving exon 5 was identified during this process. To screen canine melanoma samples for BRAF mutation in codon 599, cDNA and genomic DNA were isolated from canine malignant melanoma cell lines and primary tumor samples respectively, all from cases seen at the Veterinary Medical Teaching Hospital at the University of California, Davis. Polymerase chain reaction (PCR) was performed for exon 15 using primers based at the 5' end of exon 15 and the 5' end of intron 15 and the resultant products were directly sequenced. No mutations in codon 599 or exon 15 were identified in any of the 17 samples evaluated. However, all of the melanoma cell lines expressed BRAF and demonstrated high levels of basal ERK phosphorylation suggesting that dysregulation of this pathway is present. Therefore, similar to the case with human mucosal melanomas, canine oral malignant melanomas do not possess codon 599 BRAF mutations commonly identified in human cutaneous melanomas. This finding supports the notion that melanomas arising from non-sun-exposed sites exhibit distinct mechanisms of molecular transformation.
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Affiliation(s)
- Suzanne Shelly
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, 2112 Tupper Hall,One Shields Ave., California, 95616, USA
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Mitsutake N, Knauf JA, Mitsutake S, Mesa C, Zhang L, Fagin JA. Conditional BRAFV600E expression induces DNA synthesis, apoptosis, dedifferentiation, and chromosomal instability in thyroid PCCL3 cells. Cancer Res 2005; 65:2465-73. [PMID: 15781663 DOI: 10.1158/0008-5472.can-04-3314] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The activating mutation BRAF(T1796A) is the most prevalent genetic alteration in papillary thyroid carcinomas (PTC). It is associated with advanced PTCs, suggesting that this oncoprotein confers thyroid cancers with more aggressive properties. BRAF(T1796A) is also observed in thyroid micropapillary carcinomas and may thus be an early event in tumor development. To explore its biological consequences, we established doxycycline-inducible BRAF(V600E)-expressing clonal lines derived from well-differentiated rat thyroid PCCL3 cells. Expression of BRAF(V600E) did not induce growth in the absence of thyrotropin despite increasing DNA synthesis, which is likely explained because of a concomitant increase in apoptosis. Thyrotropin-dependent cell growth and DNA synthesis were reduced by BRAF(V600E) because of decreased thyrotropin responsiveness associated with inhibition of thyrotropin receptor gene expression. These results are similar to those obtained following conditional expression of RET/PTC. However, in contrast to RET/PTC, BRAF activation did not impair key activation steps distal to the thyrotropin receptor, such as forskolin-induced adenylyl cyclase activity or cyclic AMP-induced DNA synthesis. We reported previously that acute RET/PTC expression in PCCL3 cells did not induce genomic instability. By contrast, induction of BRAF(V600E) expression increased the frequency of micronuclei by both clastogenic and aneugenic events. These data indicate that BRAF(V600E) expression confers thyroid cells with little growth advantage because of concomitant activation of DNA synthesis and apoptosis. However, in contrast to RET/PTC, BRAF(V600E) may facilitate the acquisition of secondary genetic events through induction of genomic instability, which may account for its aggressive properties.
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Affiliation(s)
- Norisato Mitsutake
- Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0547, USA
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McDaid HM, Lopez-Barcons L, Grossman A, Lia M, Keller S, Pérez-Soler R, Horwitz SB. Enhancement of the therapeutic efficacy of taxol by the mitogen-activated protein kinase kinase inhibitor CI-1040 in nude mice bearing human heterotransplants. Cancer Res 2005; 65:2854-60. [PMID: 15805287 DOI: 10.1158/0008-5472.can-04-4391] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Taxol may contribute to intrinsic chemoresistance by activating the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) cytoprotective pathway in human cancer cell lines and tumors. We have previously shown additivity between Taxol and the MEK inhibitor, U0126 in human cancer cell lines. Here, the combination of Taxol with an orally bioavailable MEK inhibitor, CI-1040, was evaluated in human lung tumors heterotransplanted into nude mice. Unlike xenograft models that are derived from cells with multiple genetic alterations due to prolonged passage, heterotransplanted tumor models are more clinically relevant. Combined treatment with both drugs resulted in inhibition of tumor growth in all models and tumor regressions in three of four models tested, supporting our previous observation that Taxol's efficacy is potentiated by MEK inhibition. Concurrent administration was superior to intermittent dosing. Pharmacodynamic assessments of tumors indicated that suppression of MEK was associated with induction of S473 phosphorylated Akt and reduced proliferation in the combination groups relative to single agents, in addition to suppression of fibroblast growth factor-mediated angiogenesis and reduced expression of vascular endothelial growth factor. These findings are significant and indicate that this combination may have broad therapeutic applications in a diverse range of lung tumors with different intrinsic chemosensitivities.
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Affiliation(s)
- Hayley M McDaid
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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Akula SM, Ford PW, Whitman AG, Hamden KE, Bryan BA, Cook PP, McCubrey JA. B-Raf-dependent expression of vascular endothelial growth factor-A in Kaposi sarcoma-associated herpesvirus-infected human B cells. Blood 2005; 105:4516-22. [PMID: 15705790 DOI: 10.1182/blood-2004-09-3683] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8) is etiologically linked to Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease. Vascular endothelial growth factor-A (VEGF-A) is one of the essential factors required in KSHV pathogenesis, mainly due to its ability to mediate angiogenesis. In this report we analyzed the relationship between Raf and VEGF-A expression in KSHV-infected hematopoietic cells. All of the KSHV-infected cell lines (derived from PEL) expressed higher levels of B-Raf and VEGF-A when compared with uninfected cells. Inhibition of Raf to mitogen-induced extracellular kinase (MEK) to extracellular signal-related kinase (ERK) signaling, either by the use of MEK inhibitor (PD98059) or by siRNA specific to B-Raf, significantly lowered VEGF-A expression. In addition, B-Raf-induced VEGF-A expression was demonstrated to be sufficient to enhance tubule formation in endothelial cells. Interestingly, we did not observe mutation in the B-Raf gene of the KSHV-infected PEL cell lines. Taken together, we report for the first time the ability of Raf-associated signaling to play a role in the expression of VEGF-A in KSHV-infected hematopoietic cells.
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Affiliation(s)
- Shaw M Akula
- Department of Microbiology & Immunology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA.
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Mahon ES, Hawrysh AD, Chagpar RB, Johnson LM, Anderson DH. A-Raf associates with and regulates platelet-derived growth factor receptor signalling. Cell Signal 2004; 17:857-68. [PMID: 15763428 DOI: 10.1016/j.cellsig.2004.11.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2004] [Revised: 11/03/2004] [Accepted: 11/03/2004] [Indexed: 11/25/2022]
Abstract
Raf kinases are important intermediates in epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) mediated activation of the mitogen-activated protein kinase (MAPK) pathway. In this report, we show that the A-Raf kinase is associated with activated EGF receptor complexes and with PDGF receptor (PDGFR) complexes independent of prior PDGF treatment. The ability of A-Raf to associate with receptor tyrosine kinases could provide a Ras-GTP-independent mechanism for the membrane localization of A-Raf. Expression of a partially activated A-Raf mutant resulted in decreased tyrosine phosphorylation of the PDGFR, specifically on Y857 (autophosphorylation site) and Y1021 (phospholipase Cgamma1 (PLCgamma1) binding site), but not the binding sites for other signalling proteins (Nck, phosphatidylinositol 3'-kinase (PI3K), RasGAP, Grb2, SHP). Activated A-Raf expression also altered the activation of PLCgamma1, and p85-associated PI3K. Thus, A-Raf can regulate PLCgamma1 signalling via a PDGFR-dependent mechanism and may also regulate PI3K signalling via a PDGFR-independent mechanism.
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Affiliation(s)
- Elizabeth S Mahon
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Ave., Saskatoon, Saskatchewan, Canada S7N 5E5
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