p21-Activated Kinase Inhibitor II, PF-3758309

A cell-permeable pyrrolopyrazole that acts as a potent inhibitor against p21-activated kinases (K_i in nM/[ATP] in µM = 13.7/200, 18.7/40, 18.1/80. 17.1/72, respectively, in PAK1, PAK4, PAK5, PAK6 in vitro kinase assays; IC₅₀ = 190 and 99 nM against PAK1 and PAK3, respectively) and potently inhibits cellular PAK4-mediated GEF-H1 Ser810 phosphoryation (IC₅₀ = 1.3 nM using HEK293-derived TR-293-KDG cells) by directly targeting the kinase ATP-binding site in a reversible manner (K_d = 4.5 nM; k_off = 0.010/s; t_1/2 = 68 s; by SPR using rhPAK4_300-591 kinase domain). PF-3758309 is expected to inhibit cellular AMPK and RSK2 activity only at much higher concentrations (estimated IC₅₀ = 40 nM and 171 nM, respectively, assuming cellular [ATP] = 2 mM) and exhibit even less potency toward 144 other cellular kinases when administered at effective concentration range for cellular PAK1/4/5/6 inhibition. In addition to inhibiting PAK4-dependent cellular signaling (IC₅₀ = 24.2 nM against 20 ng/mL TNFα-stimulated NF-κB reporter transcription in HEK293T) and proliferation (IC₅₀ = 0.24 and 27 nM, respectively, against HCT116 and A549 colonies formation) in cultures in vitro, PF-3758309 is also reported to effectively inhibit human tumor growth in nude mice in vivo (% inhibition/tumor/BID p.o. dosage in mg/kg = 97%/HCT116/20, 106%/Colo205/20, 89%/MDA-MB231/20, 71%/A549/10, 85%/M24met/25).

Cell permeable: yes

Primary Target
PAK

Reversible: yes

Target IC₅₀: 190 and 99 nM for PAK1 and PAK3, respectively)

Packaged under inert gas

Following reconstitution, aliquot and freeze (-70°C). Stock solutions are stable for up to 6 months at -70°C.

Use only fresh DMSO for reconsitution.

Murray, B.W., et al. 2010. Proc. Natl. Acad. Sci. USA.107, 9446.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)