15 research outputs found
A Three-Hybrid Approach to Scanning the Proteome for Targets of Small Molecule Kinase Inhibitors
AbstractIn this study, we explored the application of a yeast three-hybrid (Y3H)-based compound/protein display system to scanning the proteome for targets of kinase inhibitors. Various known cyclin-dependent kinase (CDK) inhibitors, including purine and indenopyrazole analogs, were displayed in the form of methotrexate-based hybrid ligands and deployed in cDNA library or yeast cell array-based screening formats. For all inhibitors, known cell cycle CDKs as well as novel candidate CDK-like and/or CDK-unrelated kinase targets could be identified, many of which were independently confirmed using secondary enzyme assays and affinity chromatography. The Y3H system described here may prove generally useful in the discovery of candidate drug targets
A Proteome-Wide CDK/CRK-Specific Kinase Inhibitor Promotes Tumor Cell Death in the Absence of Cell Cycle Progression
SummaryThe identification of molecular determinants of tumor cell survival is an important objective in cancer research. Here, we describe a small-molecule kinase inhibitor (RGB-286147), which, besides inhibiting tumor cell cycle progression, exhibits potent cytotoxic activity toward noncycling tumor cells, but not nontransformed quiescent fibroblasts. Extensive yeast three-hybrid (Y3H)-based proteome/kinome scanning with chemical dimerizers revealed CDK1/2/3/5/7/9 and the less well-characterized CDK-related kinases (CRKs) p42/CCRK, PCTK1/3, and PFTK1 as its predominant targets. Thus, RGB-286147 is a proteome-wide CDK/CRK-specific kinase inhibitor whose further study could yield new insight into molecular determinants of tumor cell survival. Our results also suggest that the [1, 3, 6]-tri-substituted-pyrazolo[3,4-d]-pyrimidine-4-one kinase inhibitor scaffold is a promising template for the rational design of kinase inhibitors with potential applications to disease indications other than cancer, such as neurodegeneration, cardiac hypertrophic growth, and AIDS
Structure-Based Identification of Ureas as Novel Nicotinamide Phosphoribosyltransferase (Nampt) Inhibitors
Nicotinamide
phosphoribosyltransferase (Nampt) is a promising anticancer
target. Virtual screening identified a thiourea analogue, compound <b>5</b>, as a novel highly potent Nampt inhibitor. Guided by the
cocrystal structure of <b>5</b>, SAR exploration revealed that
the corresponding urea compound <b>7</b> exhibited similar potency
with an improved solubility profile. These studies also indicated
that a 3-pyridyl group was the preferred substituent at one inhibitor
terminus and also identified a urea moiety as the optimal linker to
the remainder of the inhibitor structure. Further SAR optimization
of the other inhibitor terminus ultimately yielded compound <b>50</b> as a urea-containing Nampt inhibitor which exhibited excellent
biochemical and cellular potency (enzyme IC<sub>50</sub> = 0.007 μM;
A2780 IC<sub>50</sub> = 0.032 μM). Compound <b>50</b> also
showed excellent in vivo antitumor efficacy when dosed orally in an
A2780 ovarian tumor xenograft model (TGI of 97% was observed on day
17)