Targeted Therapy for BRAFV600E Malignant Astrocytoma

Purpose: Malignant astrocytomas (MA) are aggressive central nervous system tumors with poor prognosis. Activating mutation of BRAF (BRAFV600E) has been reported in a subset of these tumors, especially in children. We have investigated the incidence of BRAFV600E in additional pediatric patient cohorts and examined the effects of BRAF blockade in preclinical models of BRAFV600E and wild-type BRAF MA. Experimental Design: BRAFV600E mutation status was examined in two pediatric MA patient cohorts. For functional studies, BRAFV600E MA cell lines were used to investigate the effects of BRAF shRNA knockdown in vitro, and to investigate BRAF pharmacologic inhibition in vitro and in vivo. Results: BRAFV600E mutations were identified in 11 and 10% of MAs from two distinct series of tumors (six of 58 cases total). BRAF was expressed in all MA cell lines examined, among which BRAFV600E was identified in four instances. Using the BRAFV600E-specific inhibitor PLX4720, pharmacologic blockade of BRAF revealed preferential antiproliferative activity against BRAFV600E mutant cells in vitro, in contrast to the use of shRNA-mediated knockdown of BRAF, which inhibited cell growth of glioma cell lines regardless of BRAF mutation status. Using orthotopic MA xenografts, we show that PLX4720 treatment decreases tumor growth and increases overall survival in mice-bearing BRAFV600E mutant xenografts, while being ineffective, and possibly tumor promoting, against xenografts with wild-type BRAF. Conclusions: Our results indicate a 10% incidence of activating BRAFV600E among pediatric MAs. With regard to implications for therapy, our results support evaluation of BRAFV600E-specific inhibitors for treating BRAFV600E MA patients. Clin Cancer Res; 17(24); 7595–604. ©2011 AACR.

[1]  A. Hauschild,et al.  Improved survival with vemurafenib in melanoma with BRAF V600E mutation. , 2011, The New England journal of medicine.

[2]  T. Zhou,et al.  Temozolomide in the treatment of children with newly diagnosed diffuse intrinsic pontine gliomas: a report from the Children's Oncology Group. , 2011, Neuro-oncology.

[3]  Kirsten Schmieder,et al.  Analysis of BRAF V600E mutation in 1,320 nervous system tumors reveals high mutation frequencies in pleomorphic xanthoastrocytoma, ganglioglioma and extra-cerebellar pilocytic astrocytoma , 2011, Acta Neuropathologica.

[4]  K. Flaherty,et al.  Inhibition of mutated, activated BRAF in metastatic melanoma. , 2010, The New England journal of medicine.

[5]  A. Ashworth,et al.  A Distinct Spectrum of Copy Number Aberrations in Pediatric High-Grade Gliomas , 2010, Clinical Cancer Research.

[6]  Richard G Grundy,et al.  Integrated molecular genetic profiling of pediatric high-grade gliomas reveals key differences with the adult disease. , 2010, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[7]  M. Prados,et al.  Pharmacologic inhibition of cyclin-dependent kinases 4 and 6 arrests the growth of glioblastoma multiforme intracranial xenografts. , 2010, Cancer research.

[8]  M. Berger,et al.  Morphologic and molecular characterization of ATRT xenografts adapted for orthotopic therapeutic testing. , 2010, Neuro-oncology.

[9]  M. Belvin,et al.  RAF inhibitors prime wild-type RAF to activate the MAPK pathway and enhance growth , 2010, Nature.

[10]  Chao Zhang,et al.  RAF inhibitors transactivate RAF dimers and ERK signaling in cells with wild-type BRAF , 2010, Nature.

[11]  C. Hawkins,et al.  Whole-genome profiling of pediatric diffuse intrinsic pontine gliomas highlights platelet-derived growth factor receptor alpha and poly (ADP-ribose) polymerase as potential therapeutic targets. , 2010, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[12]  J. Reis-Filho,et al.  Kinase-Dead BRAF and Oncogenic RAS Cooperate to Drive Tumor Progression through CRAF , 2010, Cell.

[13]  Hanlee P. Ji,et al.  Oncogenic BRAF mutation with CDKN2A inactivation is characteristic of a subset of pediatric malignant astrocytomas. , 2010, Cancer research.

[14]  R. Beroukhim,et al.  Proteasomal and genetic inactivation of the NF1 tumor suppressor in gliomagenesis. , 2009, Cancer cell.

[15]  Susan M. Chang,et al.  Phase II study of erlotinib plus temozolomide during and after radiation therapy in patients with newly diagnosed glioblastoma multiforme or gliosarcoma. , 2009, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[16]  Caterina Giannini,et al.  Phase I/II trial of erlotinib and temozolomide with radiation therapy in the treatment of newly diagnosed glioblastoma multiforme: North Central Cancer Treatment Group Study N0177. , 2008, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[17]  J. Sastre,et al.  The activation of ERK1/2 MAP kinases in glioblastoma pathobiology and its relationship with EGFRamplification , 2008, Neuropathology : official journal of the Japanese Society of Neuropathology.

[18]  D. Busam,et al.  An Integrated Genomic Analysis of Human Glioblastoma Multiforme , 2008, Science.

[19]  Joshua M. Korn,et al.  Comprehensive genomic characterization defines human glioblastoma genes and core pathways , 2008, Nature.

[20]  F. Lovat,et al.  p27Kip1 expression inhibits glioblastoma growth, invasion, and tumor-induced neoangiogenesis , 2008, Molecular Cancer Therapeutics.

[21]  Kam Y. J. Zhang,et al.  Discovery of a selective inhibitor of oncogenic B-Raf kinase with potent antimelanoma activity , 2008, Proceedings of the National Academy of Sciences.

[22]  Keith L. Ligon,et al.  Coactivation of Receptor Tyrosine Kinases Affects the Response of Tumor Cells to Targeted Therapies , 2007, Science.

[23]  Chunxu Qu,et al.  EWS/FLI-1 Induces Rapid Onset of Myeloid/Erythroid Leukemia in Mice , 2007, Molecular and Cellular Biology.

[24]  P. Wesseling,et al.  RAS/RAF pathway activation in gliomas: the result of copy number gains rather than activating mutations , 2007, Acta Neuropathologica.

[25]  D. Morrison,et al.  Integrating signals from RTKs to ERK/MAPK , 2007, Oncogene.

[26]  I. Pollack,et al.  Phase I trial of imatinib in children with newly diagnosed brainstem and recurrent malignant gliomas: a Pediatric Brain Tumor Consortium report. , 2007, Neuro-oncology.

[27]  C. James,et al.  Identification of molecular characteristics correlated with glioblastoma sensitivity to EGFR kinase inhibition through use of an intracranial xenograft test panel , 2007, Molecular Cancer Therapeutics.

[28]  A. Aplin,et al.  Mutant B-RAF signaling and cyclin D1 regulate Cks1/S-phase kinase-associated protein 2-mediated degradation of p27Kip1 in human melanoma cells , 2007, Oncogene.

[29]  C. James,et al.  Rarity of PTEN deletions and EGFR amplification in malignant gliomas of childhood: results from the Children's Cancer Group 945 cohort. , 2006, Journal of neurosurgery.

[30]  H. Ressom,et al.  Activation of p53-Dependent Growth Suppression in Human Cells by Mutations in PTEN or PIK3CA , 2006, Molecular and Cellular Biology.

[31]  S. Shete,et al.  The role of MMP-2 and MMP-9 polymorphisms in sporadic intracranial aneurysms. , 2006, Journal of neurosurgery.

[32]  B. Anandh,et al.  Expression of p53, EGFR, pRb and bcl-2 Proteins in Pediatric Glioblastoma Multiforme: A Study of 54 Patients , 2005, Pediatric Neurosurgery.

[33]  M. McMahon,et al.  Pharmacologic inhibition of RAF-->MEK-->ERK signaling elicits pancreatic cancer cell cycle arrest through induced expression of p27Kip1. , 2005, Cancer research.

[34]  Martin J. van den Bent,et al.  Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. , 2005, The New England journal of medicine.

[35]  J. Sebolt-Leopold,et al.  Targeting the mitogen-activated protein kinase cascade to treat cancer , 2004, Nature Reviews Cancer.

[36]  Richard Marais,et al.  The RAF proteins take centre stage , 2004, Nature Reviews Molecular Cell Biology.

[37]  G. Reifenberger,et al.  Mutation analysis of the Ras pathway genes NRAS, HRAS, KRAS and BRAF in glioblastomas , 2004, Acta Neuropathologica.

[38]  B. Weber,et al.  SPRY2 Is an Inhibitor of the Ras/Extracellular Signal-Regulated Kinase Pathway in Melanocytes and Melanoma Cells with Wild-Type BRAF but Not with the V599E Mutant , 2004, Cancer Research.

[39]  Siegfried Kropf,et al.  Prognostic relevance of MAPK expression in glioblastoma multiforme. , 2003, International journal of oncology.

[40]  A. Nicholson,et al.  Mutations of the BRAF gene in human cancer , 2002, Nature.

[41]  I. Pollack,et al.  Expression of p53 and prognosis in children with malignant gliomas. , 2002, The New England journal of medicine.

[42]  I. Pollack,et al.  Age and TP53 mutation frequency in childhood malignant gliomas: results in a multi-institutional cohort. , 2001, Cancer research.

[43]  J. Vincent,et al.  Raf‐1 and B‐Raf proteins have similar regional distributions but differential subcellular localization in adult rat brain , 1999, The European journal of neuroscience.

[44]  Y. Yonekawa,et al.  Determination of p53 mutations, EGFR overexpression, and loss of p16 expression in pediatric glioblastomas. , 1997, Journal of neuropathology and experimental neurology.

[45]  C. Marshall,et al.  Differential Regulation of Raf-1, A-Raf, and B-Raf by Oncogenic Ras and Tyrosine Kinases* , 1997, The Journal of Biological Chemistry.

[46]  J. Pouysségur,et al.  Cyclin D1 Expression Is Regulated Positively by the p42/p44MAPK and Negatively by the p38/HOGMAPK Pathway* , 1996, The Journal of Biological Chemistry.

[47]  T. Eberlein,et al.  Improved Survival with Vemurafenib in Melanoma with BRAF V600E Mutation , 2012 .