Lafanechère L
Centre de Criblage pour des Molécules Bio-Actives Institut de Recherches en Technologies et Sciences pour le Vivant iRTSV/CMBA CEA/GRENOBLE 17, rue des Martyrs 38054 GRENOBLE Cedex 9 FRANCE

Abstract:

Understanding cell motility requires detailed knowledge of the localization of signalling networks regulating actin polymerization and of their dynamics. Specific drugs, targeting enzymes involved in cell motility regulating pathways, would help to understand these fundamental processes and may lead to novel therapeutic opportunities targeting cancer metastasis. The Rho-GTPase pathway is centrally involved in cell motility regulation. Apart from known ROC Kinase inhibitors, however, other inhibitors that target this pathway are scare.

In the aim to find new regulators of microtubule dynamics, we conducted a forward chemical genetics strategy, using as a first step a multiparametric cell-based assay which probes the microtubule polymerization status. This assay can discriminate between dynamic microtubules and stabilized microtubules. We screened a library of 14,720 compounds and identified a pyridocarbazolone that reversibly blocked microtubules and actin microfilament dynamics and inhibited cell motility but did not directly target tubulin or actin. We found that this pyridocarbazolone selectively targets LIM Kinases (LIMKs).   Phosphorylation of the actin binding protein cofilin by LIMKs is the last step of the Rho-GTPase cascade that regulates actin dynamics. We also demonstrated that LIMK regulates both actin microfilaments and microtubule dynamics and strengthen earlier work indicating that LIMK can be a coordinator of the actin and the microtubule cytoskeletons. This compound is a new selective and attractive tool for our understanding of the role of LIMK in the regulation of microtubule and actin dynamics.  Moreover, it represents an interesting chemical lead for the treatment of tumours and metastasis.