Small-molecule p21-activated kinase inhibitor PF-3758309 is a potent inhibitor of oncogenic signaling and tumor growth - PubMed (original) (raw)

. 2010 May 18;107(20):9446-51.

doi: 10.1073/pnas.0911863107. Epub 2010 May 3.

Chuangxing Guo, Joseph Piraino, John K Westwick, Cathy Zhang, Jane Lamerdin, Eleanor Dagostino, Daniel Knighton, Cho-Ming Loi, Michael Zager, Eugenia Kraynov, Ian Popoff, James G Christensen, Ricardo Martinez, Susan E Kephart, Joseph Marakovits, Shannon Karlicek, Simon Bergqvist, Tod Smeal

Affiliations

Small-molecule p21-activated kinase inhibitor PF-3758309 is a potent inhibitor of oncogenic signaling and tumor growth

Brion W Murray et al. Proc Natl Acad Sci U S A. 2010.

Abstract

Despite abundant evidence that aberrant Rho-family GTPase activation contributes to most steps of cancer initiation and progression, there is a dearth of inhibitors of their effectors (e.g., p21-activated kinases). Through high-throughput screening and structure-based design, we identify PF-3758309, a potent (K(d) = 2.7 nM), ATP-competitive, pyrrolopyrazole inhibitor of PAK4. In cells, PF-3758309 inhibits phosphorylation of the PAK4 substrate GEF-H1 (IC(50) = 1.3 nM) and anchorage-independent growth of a panel of tumor cell lines (IC(50) = 4.7 +/- 3 nM). The molecular underpinnings of PF-3758309 biological effects were characterized using an integration of traditional and emerging technologies. Crystallographic characterization of the PF-3758309/PAK4 complex defined determinants of potency and kinase selectivity. Global high-content cellular analysis confirms that PF-3758309 modulates known PAK4-dependent signaling nodes and identifies unexpected links to additional pathways (e.g., p53). In tumor models, PF-3758309 inhibits PAK4-dependent pathways in proteomic studies and regulates functional activities related to cell proliferation and survival. PF-3758309 blocks the growth of multiple human tumor xenografts, with a plasma EC(50) value of 0.4 nM in the most sensitive model. This study defines PAK4-related pathways, provides additional support for PAK4 as a therapeutic target with a unique combination of functions (apoptotic, cytoskeletal, cell-cycle), and identifies a potent, orally available small-molecule PAK inhibitor with significant promise for the treatment of human cancers.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.

Fig. 1.

Structural characterization of PF-3758309 binding to the PAK4 catalytic domain. (A) Chemical structure of PF-3758309. (B) PF-3758309 in 2.1 Å PAK4 catalytic domain x-ray cocrystal structure (Protein Data Bank ID code 2x4z). (C) Binding of PF-3758309 in the active site of PAK4 (surface color-coded by hydrophobicity).

Fig. 2.

Fig. 2.

PF-3758309 has a unique profile of cellular activity. Cellular analysis was performed using a panel of over 113 cell-based assays, composed of both high-content and functional readouts, most performed at multiple time points. The group of assays shown was consistently regulated by diverse PAK4 inhibitors. Displayed in red is the core assay profile for PF-3758309 (1 μM); the Src-family kinase inhibitor Dasatinib (1 μM; green bars) is included for comparison. Each bar represents percent of inhibition stimulation relative to assay-specific controls from at least three independent experiments, ± SD (

SI Materials and Methods

).

Fig. 3.

Fig. 3.

Tumor growth inhibition of human xenograft tumor models: HCT116 (CRC), M24met (melanoma), Colo205 (CRC), A549 lung carcinoma, GTL-16 (GIST), DLD1 (CRC), and MDA-MB231 (BC). All TGI measurements were statistically significant except 20 mg/kg dosing of the c-Met-driven GTL-16 model (45).

Fig. 4.

Fig. 4.

PF-3758309 is antiproliferative and induces apoptosis in a HCT116 tumor model. PF-3758309 functional activity was measured by IHC in an HCT116 model with Ki67 expression and caspase 3 activation endpoints. (A) Ki67 and caspase 3 activation IHC analysis at 25 mg/kg PF-3758309. (B and C) Quantitation of the IHC images. Tumor-bearing mice were p.o. administered with vehicle (solid bars) and 15 mg/kg (open bars) and 25 mg/kg (striped bars) PF-3758309 twice daily and tumors were harvested at the indicated times.

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References

    1. Ma WW, Adjei AA. Novel agents on the horizon for cancer therapy. CA Cancer J Clin. 2009;59:111–137. - PubMed
    1. Onesto C, Shutes A, Picard V, Schweighoffer F, Der CJ. Characterization of EHT 1864, a novel small molecule inhibitor of Rac family small GTPases. Methods Enzymol. 2008;439:111–129. - PubMed
    1. Qiu RG, Chen J, McCormick F, Symons M. A role for Rho in Ras transformation. Proc Natl Acad Sci USA. 1995;92:11781–11785. - PMC - PubMed
    1. Zohn IM, Campbell SL, Khosravi-Far R, Rossman KL, Der CJ. Rho family proteins and Ras transformation: The RHOad less traveled gets congested. Oncogene. 1998;17(11 Reviews):1415–1438. - PubMed
    1. Sahai E, Olson MF, Marshall CJ. Cross-talk between Ras and Rho signalling pathways in transformation favours proliferation and increased motility. EMBO J. 2001;20:755–766. - PMC - PubMed

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