Drug ‘clicking’ on cell-penetrating fluorescent nanoparticles for in cellulo chemical proteomics

Chemical proteomics approaches are widely used to identify molecular targets of existing or novel drugs. This manuscript describes the development of a straightforward approach to conjugate azide-labeled drugs via click chemistry to alkyne-tagged cell-penetrating fluorescent nanoparticles as a novel tool to study target engagement and/or identification inside living cells. A modification of the Baeyer test for alkynes allows monitoring the Cu­(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction, guaranteeing the presence of the drug on the solid support. As a proof of concept, the conjugation of the promiscuous kinase inhibitor dasatinib to Cy5-labeled nanoparticles is presented. Dasatinib-decorated fluorescent nanoparticles efficiently inhibited its protein target SRC in vitro, entered cancer cells, and colocalized with SRC in cellulo

Efficient Palladium-Triggered Release of Vorinostat from a Bioorthogonal Precursor

Bioorthogonal uncaging strategies have recently emerged as an experimental therapeutic approach to control drug release. Herein we report a novel masking strategy that enables to modulate the metal chelating properties of hydroxamic acid groups by bioorthogonal chemistry using Pd-functionalized resins. This novel approach allowed to devise an inactive precursor of the histone deacetylase inhibitor vorinostat that was efficiently uncaged by heterogeneous Pd catalysis in cell culture models of glioma and lung cancer

Synthesis and characterization of a click-assembled 18-atom macrocycle that displays selective AXL kinase inhibitory activity

A novel macrocyclic construct consisting of a pyrazolopyrimidine scaffold concatenated to a benzene ring through two triazoles has been developed to investigate uncharted chemical space with bioactive potential. The 18-atom macrocycle was assembled via a double copper-catalyzed alkyne−azide cycloaddition (CuAAC) reaction between 1,3- bis(azidomethyl)benzene and a bis-propargylated pyrazolo[3,4-d]pyrimidine core. The resulting macrocycle was functionalized further into a multicyclic analog that displays selective inhibitory activity against the receptor tyrosine kinase AXL.O.C.-L. and B.L. thank Spain Ministry of Education, Culture and Sport and the Erasmus + Traineeship programme for funding, respectively. C.T. thanks the CMVM for a Principal’s Scholarship. F.F. acknowledges support from Universidad de Granada. SHM and AU-B are grateful to Scottish Power and CRUK for funding

Development of potent inhibitors of receptor tyrosine kinases by ligand-based drug design and target-biased phenotypic screening

Pyrazolopyrimidines with potent antiproliferative properties were developed by an adaptive strategy that applies ligand-based design and phenotypic screening iteratively and is informed by biochemical assays. To drive development toward specific oncopathways, compounds were tested against cancer cells that overexpress, or not, AXL kinase. Identified phenotypic hits were found to inhibit oncotargets AXL, RET, and FLT3. Subsequent optimization generated antiproliferative lead compounds with unique selectivity profiles, including selective AXL inhibitors and a highly potent inhibitor of FLT3

Design and manufacture of functional catalyst-carrier structures for the bioorthogonal activation of anticancer agents

Novel palladium (Pd)-loaded titanium (Ti) devices with high biocompatibility and catalytic activity were prepared using a range of fabrication methods such as powder metallurgy (i.e. sintering with and without space-holder), sputtering, pulsed laser deposition and supersonic cluster beam deposition. The surface of the Ti-[Pd] devices were physico-chemically characterised to confirm the non-alloyed state of the Pd coating onto the titanium substrate. The Pd thickness was optimised to achieve maximum surface area (i.e. maximum catalytic effect) using the minimum amount of material in each method for cost effective production. The catalytic response of the different Ti-[Pd] devices was evaluated under biocompatible conditions by employing an off-on Pd-activatable fluorescent probe. The most robust coating of Pd was produced by an optimised magnetron sputtering method. The sputtered Ti-[Pd] devices were selected to induce the bioorthogonal uncaging of the anticancer drug Vorinostat from a pharmacologically-inactive Pd-activatable precursor in cancer cell culture, demonstrating the capacity of these devices to mediate a local anti-tumour effect via in-situ release of a clinically approved drug. This approach is the first step towards surgically implantable devices that could facilitate targeting affected areas with high spatial selectivity, improving pharmacological activity and reducing systemic side effects through localised treatment directly at the cancer site