ZCL278 is a selective Cdc42 GTPase inhibitor.

GTPase CDC42:11.4 μM(Kd)

ZCL278 reduces the JUNV RNA load in the spleen by over 33-fold, rendering JUNV RNA undetectable in 5 of 8 mice. These results mirror those observed in Gabapentin-treated mice, demonstrating ZCL278's ability to abrogate JUNV replication [2].

Lyophilized Cdc42 protein is reconstituted to 5 mg/mL in a buffer consisting of 50 mM Tris, 0.5 mM MgCl2, 50 mM NaCl, 3% (wt/vol) sucrose, and 0.6% dextran. The stock solution is then diluted to 1 μM in 5 mM phosphate buffer, pH 7.4. Into a quartz cuvettete containing Cdc42 solution, aliquots of ZCL278 are added and incubated for 5 min before each fluorescent measurement. The excitation wavelength is 275 nm, and the fluorescence of tryptophan at 350 nm is measured after each addition. The titration curve is fitted using the equimolar specific binding model in GraphPad, and the Kd is calculated[1].

ZCL278 is prepared in DMSO and stored, and then diluted with appropriate medium before use[1]. To determine cell viability, PC-3 cells are incubated for 24 h with or without the Cdc42 activator, ZCL278, or NSC23766. By using the trypan blue dye exclusion method, the numbers of live and dead cells are obtained with a Countess Automated Cell Counter. P values are assigned in each experiment, and any null hypothesis with probability level <95% is rejected[1].