A Genetic Progression Model of BrafV600E-Induced Intestinal Tumorigenesis Reveals Targets for Therapeutic Intervention
Menée à l'aide d'un modèle murin, cette étude met en évidence des mécanismes par lesquels, en association avec une instabilité microsatellitaire, l'inactivation du gène p16Ink4a et une mutation de p53, la mutation V600E du gène BRAF induit l'évolution cancéreuse d'un adénome dentelé du côlon
We show that BRAFV600E initiates an alternative pathway to colorectal cancer (CRC), which progresses through a hyperplasia/adenoma/carcinoma sequence. This pathway underlies significant subsets of CRCs with distinctive pathomorphologic/genetic/epidemiologic/clinical characteristics. Genetic and functional analyses in mice revealed a series of stage-specific molecular alterations driving different phases of tumor evolution and uncovered mechanisms underlying this stage specificity. We further demonstrate dose-dependent effects of oncogenic signaling, with physiologic BrafV600E expression being sufficient for hyperplasia induction, but later stage intensified Mapk-signaling driving both tumor progression and activation of intrinsic tumor suppression. Such phenomena explain, for example, the inability of p53 to restrain tumor initiation as well as its importance in invasiveness control, and the late stage specificity of its somatic mutation. Finally, systematic drug screening revealed sensitivity of this CRC subtype to targeted therapeutics, including Mek or combinatorial PI3K/Braf inhibition.
"We present a progression model of BrafV600E-initiated serrated intestinal cancer
"Stage-specific genetic alterations drive sequential tumorigenesis
"Oncogenic signaling triggered by mutant Braf displays dose-dependent effects
"Large-scale pharmacologic profiling reveals new approaches for therapeutic targeting
Cancer cell , article en libre accès, 2012