The family of Polo-like Kinases is important in the regulation of mitotic progression; this work keys on one member, namely Polo-like Kinase 4 (PLK4). PLK4 has been identified as a candidate anti-cancer target which prompted a search for potent and selective inhibitors of PLK4. The body of the paper describes lead generation and optimization work which yielded nanomolar PLK4 inhibitors. Lead generation began with directed virtual screening, using a ligand based focused library and a PLK4 homology model. Validated hits were used as starting points for the design and discovery of PLK4 inhibitors of novel structure, namely (E)-3-((1H-indazol-6-yl)methylene)indolin-2-ones. Computational models, based on a published X-ray structure (PLK4 kinase domain), were used to understand and optimize the in vitro activity of the series; potent anti-proliferative activity was obtained. The kinase selectivity profile and cell cycle analysis of selected inhibitors are described. The results of a xenograft study with an optimized compound 50 (designated CFI-400437) support the potential of these novel PLK4 inhibitors for cancer therapy.
"Although these molecules such as indolinone 15 showed potent PLK4 inhibition, antiproliferative activity and robust tumor inhibition , some drawbacks were also observed in these inhibitors, namely the strong inhibition of CYP450, low pharmacokinetic properties (low oral exposure particularly) and configurational lability  . So the key questions are to further improve the drug-like properties of these inhibitors through rational modifications . "
"The FDA approval of sunitinib paved the way to design and synthesis of various isatin-based molecules with diverse activities against cancer . In this context, many synthetic isatin-based derivatives were developed to inhibit diverse tyrosine and serine/threonine kinases, to name just a few, c-Met kinase , c-Src kinase , RET kinase , FLT3 kinase , cyclin-dependent kinases (CDKs) , glycogen synthase kinase 3b (GSK-3b) , Aurora B kinase , p38a MAP kinase , JNK3 MAP kinase , p90 ribosomal S6 protein kinase 2 (RSK2)  and Polo-like kinase 4 (PLK4)  . Over the last decade, numerous studies pointed out the importance of isatin based anticancer hybrids as promising chemotherapeutic agents. "
[Show abstract][Hide abstract] ABSTRACT: The Nek2 and Plk4 kinases serve as crucial regulators of mitotic processes such as the centrosome duplication cycle and spindle assembly. Deregulation of these processes can trigger chromosome instability and aneuploidy, which are hallmarks of many solid tumors, including breast cancer. Emerging data from the literature illustrated various functions of Nek2 in breast cancer models, with compelling evidence of its prognostic value in breast tumors. The two kinases control distinct steps in the centrosome-centriole cycle and their dysregulation lead to centrosome amplification, marked by the presence of more than two centrosomes within the cell. We found single or composite overexpression of these kinases in breast tumor samples, regardless of subtype, which strongly associated with poor prognosis. Interestingly, in a panel of established cell lines, both kinases are highly expressed in Her2-positive breast cancer cells exhibiting centrosome amplification and trastuzumab resistance. In summary, it appears that Nek2 and Plk4 might synergize to promote breast tumorigenesis and may also be involved in tamoxifen and trastuzumab resistance.
Frontiers in Bioscience 01/2014; 19(2):352-65. DOI:10.2741/4212 · 3.52 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.