A WXW Motif Is Required for the Anticancer Activity of the TAT-RasGAP317–326 Peptide

David Barras,Nadja Chevalier,Vincent Zoete,Rosemary Dempsey,Karine Lapouge,Monilola A Olayioye,Olivier Michielin,Christian Widmann

doi:10.1074/jbc.m114.576272

Abstract

TAT-RasGAP317-326, a cell-permeable 10-amino acid-long peptide derived from the N2 fragment of p120 Ras GTPase-activating protein (RasGAP), sensitizes tumor cells to apoptosis induced by various anticancer therapies. This RasGAP-derived peptide, by targeting the deleted in liver cancer-1 (DLC1) tumor suppressor, also hampers cell migration and invasion by promoting cell adherence and by inhibiting cell movement. Here, we systematically investigated the role of each amino acid within the RasGAP317-326 sequence for the anticancer activities of TAT-RasGAP317-326. We report here that the first three amino acids of this sequence, tryptophan, methionine, and tryptophan (WMW), are necessary and sufficient to sensitize cancer cells to cisplatin-induced apoptosis and to reduce cell migration. The WMW motif was found to be critical for the binding of fragment N2 to DLC1. These results define the interaction mode between the active anticancer sequence of RasGAP and DLC1. This knowledge will facilitate the design of small molecules bearing the tumor-sensitizing and antimetastatic activities of TAT-RasGAP317-326.

Highlights

TAT-RasGAP317–326 is a Ras GTPase-activating protein (RasGAP)-derived peptide that requires deleted in liver cancer-1 (DLC1) for its antimetastatic activities
TAT-RasGAP317–326, a cell-permeable 10-amino acid-long peptide derived from the N2 fragment of p120 Ras GTPase-activating protein (RasGAP), sensitizes tumor cells to apoptosis induced by various anticancer therapies
We found that the TAT-RasGAP317–326 molecular properties by which it induces adhesion and inhibits migration rely on modulation of the actin cytoskeleton and requires deleted in liver cancer-1 (DLC1), a RhoGAP that functions as a tumor and metastasis suppressor [11, 14]

Summary

Introduction

TAT-RasGAP317–326 is a Ras GTPase-activating protein (RasGAP)-derived peptide that requires deleted in liver cancer-1 (DLC1) for its antimetastatic activities. TAT-RasGAP317–326, a cell-permeable 10-amino acid-long peptide derived from the N2 fragment of p120 Ras GTPase-activating protein (RasGAP), sensitizes tumor cells to apoptosis induced by various anticancer therapies. This RasGAP-derived peptide, by targeting the deleted in liver cancer-1 (DLC1) tumor suppressor, hampers cell migration and invasion by promoting cell adherence and by inhibiting cell movement. The WMW motif was found to be critical for the binding of fragment N2 to DLC1 These results define the interaction mode between the active anticancer sequence of RasGAP and DLC1. This knowledge will facilitate the design of small molecules bearing the tumor-sensitizing and antimetastatic activities of TATRasGAP317–326

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Conclusion