Rational Design of Small Molecule Inhibitors Targeting RhoA Subfamily Rho GTPases

SummaryRho GTPases have been implicated in diverse cellular functions and are potential therapeutic targets. By virtual screening, we have identified a Rho-specific inhibitor, Rhosin. Rhosin contains two aromatic rings tethered by a linker, and it binds to the surface area sandwiching Trp58 of RhoA with a submicromolar Kd and effectively inhibits GEF-catalyzed RhoA activation. In cells, Rhosin specifically inhibited RhoA activity and RhoA-mediated cellular function without affecting Cdc42 or Rac1 signaling activities. By suppressing RhoA or RhoC activity, Rhosin could inhibit mammary sphere formation by breast cancer cells, suppress invasion of mammary epithelial cells, and induce neurite outgrowth of PC12 cells in synergy with NGF. Thus, the rational designed RhoA subfamily-specific small molecule inhibitor is useful for studying the physiological and pathologic roles of Rho GTPase.

► A lead inhibitor, Rhosin, targeting the GEF-interactive site of RhoA was identified by virtual screen ► Rhosin binds to RhoA and inhibits RhoA-RhoGEF interaction ► Rhosin exhibits dose-dependent, reversible inhibitory activity toward RhoA ► Rhosin is useful in studying the role of RhoA subfamily GTPases and Rho-mediated cell functions.