Grassofermata

Grassofermata is a dual Arf1/Arf6 activation inhibitor. ADP ribosylation factors (Arfs) are members of the Arf family of GTP-binding proteins of the Ras superfamily. IC50 & Target:Arf6^[1][2]
Arf1^[2] In Vitro: Grassofermata directly binds to Arf6. Based on a structural homology model of the Arf6/Arf6-GEF complex, it is predicted that Grassofermata associates with Arf6 at the Arf6 GEF-binding area, which is distinct from the guanine nucleotide-binding pocket of Arf6. Grassofermata blocks ARNO- and GEP100-mediated guanine nucleotide exchange on Arf6. The treatment of uveal melanoma cells with Grassofermata interferes with anchorage-independent growth of the cell^[1]. Grassofermata is a dual Arf1/Arf6 inhibitor and is more effective toward Arf1 than Arf6. Grassofermata blocks spontaneous activation of Arf6 and its activation by cytohesins and BRAG. Grassofermata is an inhibitor of the spontaneous activation of Arf6, and it also inhibits the activation of Arf6 by its GEFs, ARNO and BRAG2, in solution. The inhibitory profile of Grassofermata is analyzed at a concentration of 25 μM, which is reported to result in almost total inhibition of spontaneous and GEF-stimulated Arf6 activation in vitro. Under the conditions used in assays, Grassofermata inhibits spontaneous nucleotide exchange of Δ13Arf6 by ~15%. Grassofermata inhibits the activation of Δ13Arf6 by BRAG2^Sec7PH by 25%. Δ17Arf1 has no measurable spontaneous nucleotide exchange. Activation of Δ17Arf1 by BRAG2^Sec7PH is inhibited by Grassofermata, and the efficiency is markedly higher than that for Arf6 (50%). In a dose-response experiment, nucleotide exchange rates are reduced by 50% by 10 μM Grassofermata for Δ17Arf1 while 50% inhibition is not achieved even at 25 μM Grassofermata for Δ13Arf6^[2]. In Vivo: Systemic treatment of mice with NAV-2729 interfere with tumorigenesis and tumor growth in orthotopic xenograft mouse model of uveal melanoma^[1].