학술논문

Disruption of CRAF-Mediated MEK Activation Is Required for Effective MEK Inhibition in KRAS Mutant Tumors.
Document Type
Article
Source
Cancer Cell. May2014, Vol. 25 Issue 5, p697-710. 14p.
Subject
*MELANOMA
*PROTO-oncogenes
*MITOGEN-activated protein kinases
*GENETIC mutation
*ENZYME inhibitors
*CELLULAR signal transduction
Language
ISSN
1535-6108
Abstract
Summary: MEK inhibitors are clinically active in BRAFV600E melanomas but only marginally so in KRAS mutant tumors. Here, we found that MEK inhibitors suppress ERK signaling more potently in BRAFV600E, than in KRAS mutant tumors. To understand this, we performed an RNAi screen in a KRAS mutant model and found that CRAF knockdown enhanced MEK inhibition. MEK activated by CRAF was less susceptible to MEK inhibitors than when activated by BRAFV600E. MEK inhibitors induced RAF-MEK complexes in KRAS mutant models, and disrupting such complexes enhanced inhibition of CRAF-dependent ERK signaling. Newer MEK inhibitors target MEK catalytic activity and also impair its reactivation by CRAF, either by disrupting RAF-MEK complexes or by interacting with Ser 222 to prevent MEK phosphorylation by RAF. [ABSTRACT FROM AUTHOR]