Cancer selective cell death induction by a bivalent CK2 inhibitor targeting the ATP site and the allosteric αD pocket.

Although the involvement of protein kinase CK2 in cancer is well-documented, there is a need for selective CK2 inhibitors suitable for investigating CK2 specific roles in cancer-related biological pathways and further exploring its therapeutic potential. Here, we report the discovery of AB668, an outstanding selective inhibitor that binds CK2 through a bivalent mode, interacting both at the ATP site and an allosteric αD pocket unique to CK2. Using caspase activation assay, live-cell imaging, and transcriptomic analysis, we have compared the effects of this bivalent inhibitor to representative ATP-competitive inhibitors, CX-4945, and SGC-CK2-1. Our results show that in contrast to CX-4945 or SGC-CK2-1, AB668, by targeting the CK2 αD pocket, has a distinct mechanism of action regarding its anti-cancer activity, inducing apoptotic cell death in several cancer cell lines and stimulating distinct biological pathways in renal cell carcinoma.

Combretastatin A-4 sulfur-containing heterocyclic derivatives: Synthesis, antiproliferative activities and molecular docking studies.

Combretastatin A-4 inspired heterocyclic derivatives were synthesized and evaluated for their biological activities on tubulin polymerization and cell proliferation. Among the 19 described sulfur-containing compounds, derivatives (Z)-4h and (Z)-4j exhibited interesting in cellulo tubulin polymerization inhibition and antiproliferative activities with IC50 values for six different cell lines between 8 and 27 nM. Furthermore, in silico docking studies within the colchicine/CA-4 binding site of tubulin were carried out to understand the interactions of our products with the protein target. The effects on the cell cycle of follicular lymphoma cells were also investigated at 1-10 nM concentrations showing that apoptotic processes occurred.

Fragment Linking Strategies for Structure-Based Drug Design.

Fragment-based drug discovery is a strategy widely used in both academia and pharmaceutical companies to generate small-molecule protein inhibitors and drug candidates. Among the approaches reported in the literature (growing, linking, and merging), the linking approach theoretically offers the opportunity to rapidly gain in binding energy. Nevertheless, this approach is poorly represented when considering the compounds currently in clinical trials. Here, we report an exhaustive view of the cases published so far in the literature, together with the methods used to identify the two initial fragments either simultaneously or successively. We review the different types of linkers published and discuss how these linkers are designed to obtain the lead compound. Mixing merging and linking methods, where the linker is duplicated from a known inhibitor, appears as an interesting strategy. To reach superadditivity, we propose to grow one of the fragments in order to minimize the distance between the two binders and then link the resulting compounds using flexible alkyl-derived linkers.