CK-636 (CK-0944636), an Arp2/3 complex inhibitor, can inhibit actin polymerization induced by the human (IC50: 4 μM), fission yeast (IC50: 24 μM) and bovine (IC50: 32 μM) Arp2/3 complex, respectively.

Arp2/3 complex (fission yeast):24 μM, Arp2/3 complex (human):4 μM, Arp2/3 complex (bovine):32 μM

CK-636 slows down cell migration by inhibiting the formation of lamellipodia at the leading edge of migrating T-cells. In live cells, it suppresses actin polymerization mediated by the Arp2/3 complex. In infected SKOV3 cells, CK-636 reduces the formation of actin filaments. Moreover, a majority of T-cells treated with CK-636 exhibit a turning event upon encountering a zigzag-shaped interface during a letter-shaped test experiment.

HDAC inhibition assays: HDAC inhibition assays are performed by Reaction Biology Corp. using isolated human, recombinant full2length HDAC1 and -6 from a baculovirus expression system in Sf9 cells. An acetylated fluorogenic peptide,RHKKAc, derived from residues 379-382 of p53 is used as substrate. The reaction buffer is made up of 50 mM Tris-HCl pH 8.0, 127 mM NaCl, 2.7 mM KCl, 1 mM MgCl2, 1 mg/mL BSA, and a final concentration of 1% DMSO. Compounds are delivered in DMSO and delivered to enzyme mixture with preincubation of 5-10 min followed by substrate addition and incubation for 2 h at 30°C. Trichostatin A and developer are added to quench the reaction and generate fluorescence, respectively. Dose-response curves are generated starting at 30 μM compound with three-fold serial dilutions to generate a 10-dose plot. IC50 values are then generated from the resulting plots, and the values expressed are the average of duplicate trials ± standard deviation.