Genetic targeting of B-RafV600E affects survival and proliferation and identifies selective agents against BRAF-mutant colorectal cancer cells

Molecular Cancer

Research

Andreas Ziesch¹  Eike Gallmeier¹  Frank T Kolligs²  Maximilian Marschall²  Benjamin Hirschi³ 

[1] Department of Internal Medicine II, University of Munich, Marchioninistr. 15, D-81377, Munich, Germany;Department of Internal Medicine II, University of Munich, Marchioninistr. 15, D-81377, Munich, Germany;German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany;Department of Internal Medicine II, University of Munich, Marchioninistr. 15, D-81377, Munich, Germany;Institute of Stem Cell Research, Helmholtz Center Munich, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany;

关键词: BRAF;    Colorectal cancer;    Knockout;    Pharmacogenetics;   

DOI  :  10.1186/1476-4598-13-122

 received in 2013-08-11, accepted in 2014-05-09,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundColorectal cancers carrying the B-Raf V600E-mutation are associated with a poor prognosis. The purpose of this study was to identify B-RafV600E-mediated traits of cancer cells in a genetic in vitro model and to assess the selective sensitization of B-RafV600E-mutant cancer cells towards therapeutic agents.MethodsSomatic cell gene targeting was used to generate subclones of the colorectal cancer cell line RKO containing either wild-type or V600E-mutant B-Raf kinase. Cell-biologic analyses were performed in order to link cancer cell traits to the BRAF-mutant genotype. Subsequently, the corresponding tumor cell clones were characterized pharmacogenetically to identify therapeutic agents exhibiting selective sensitivity in B-RafV600E-mutant cells.ResultsGenetic targeting of mutant BRAF resulted in restoration of sensitivity to serum starvation-induced apoptosis and efficiently inhibited cell proliferation in the absence of growth factors. Among tested agents, the B-Raf inhibitor dabrafenib was found to induce a strong V600E-dependent shift in cell viability. In contrast, no differential sensitizing effect was observed for conventional chemotherapeutic agents (mitomycin C, oxaliplatin, paclitaxel, etoposide, 5-fluorouracil), nor for the targeted agents cetuximab, sorafenib, vemurafenib, RAF265, or for inhibition of PI3 kinase. Treatment with dabrafenib efficiently inhibited phosphorylation of the B-Raf downstream targets Mek 1/2 and Erk 1/2.ConclusionMutant BRAF alleles mediate self-sufficiency of growth signals and serum starvation-induced resistance to apoptosis. Targeting of the BRAF mutation leads to a loss of these hallmarks of cancer. Dabrafenib selectively inhibits cell viability in B-RafV600E mutant cancer cells.

【 授权许可】

Unknown   
© Hirschi et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.