The Mechanism of Allosteric Coupling in Choline Kinase α1 Revealed by the Action of a Rationally Designed Inhibitor

Preclinical Characterization of RSM-932A, a Novel Anticancer Drug Targeting the Human Choline Kinase Alpha, an Enzyme Involved in Increased Lipid Metabolism of Cancer Cells

“…Furthermore, MN58b showed a much higher specificity against ChoKa1 (IC 50 ¼ 5 mmol/L) than against ChoKb (IC 50 ¼ 107.5 mmol/L), this is 21.5 times more potent against ChoKa1 than ChoKb isoform (24). All these results have been validated by ChoKa-specific RNA-interfering (siRNA) approaches (7,(25)(26)(27) and additional small molecules directed toward ChoKa (28)(29).…”

“…Once the proof-of-principle that ChoKa is a validated target in oncology has been set up, a very intensive activity has been developed for the identification of novel ChoKa inhibitors with potential use as antitumoral drugs (15)(16)(17)(18)(19)(20)(28)(29)(30)(31) and also as antiparasitic compounds (32,33).…”

Determination of Potential Scaffolds for Human Choline Kinase α1 by Chemical Deconvolution Studies

“…[5] The goal was to occupy both the ATP and the choline binding sites of the enzyme, as clearly demonstrated by the crystal structure of CHOKa1 in complexation with one of the compounds in this series (compound 1, PDB ID: 3ZM9). [6] Whereas adenine occupies the ATP binding site, the pyridinium fragment, through its positive charge delocalised over the nitrogen atoms, mimics the positive charge present in choline or in HC-3 (Scheme 1). We have also demonstrated that com-pound 1 induces a significant allosteric coupling between the two monomers of the enzyme, characterised by a negative cooperativity and a broken symmetry.…”

“…[6] Compound 1 interacts first with a monomer of dimeric CHOKa1 with a dissociation constant (K d1 ) of 38 nm, thereby being the most potent compound of this subfamily, showing an affinity five times stronger than that of HC-3 (Table S1). However, this first interaction induces a negative cooperativity effect into the second monomer, leading to a K d2 value of only 190 nm (Table S1).…”

“…We have also demonstrated that com-pound 1 induces a significant allosteric coupling between the two monomers of the enzyme, characterised by a negative cooperativity and a broken symmetry. [6] Here we have selected three additional potent compounds of this series together with compound 1 for in-depth biophysical and structural characterisation (Scheme 1, compounds 1-4). We conducted isothermal titration microcalorimetry (ITC), tryptophan fluorescence spectroscopy, protein X-ray crystallography, chemical deconvolution and modelling studies.…”