Choline Transporter Inhibitor II, ML352

A cell-permeable pyridinylpropanylthiophene-carboxamide compound that exhibits selective affinity toward MT/microtubule-bound KIFC1 motor domain (Q305-K673; K_d = 690 nM), but not to uncomplexed KIFC1 or MT, and selectively inhibits MT-induced, but not basal, KIFC1 motor domain ATPase activity (IC₅₀ = 300 nM; [KIFC1] = 30 nM, [MT] = 100 nM, [ATP] = 15 µM) in an ATP-competitive (K_i = 43 nM; [KIFC1] = 125 nM, [MT] = 1.5 µM) and MT-noncompetitive manner, effectively preventing ADP release, while displaying little potency against 9 other kinesin motor proteins (<15% or no inhibition at 5 µM against human CENP-E, Chromokinesin/KIF4A, Eg5, KIFC3, KIF3C, KInesin Heavy Chain/KIF5B, MCAK/KIF2C, MKLP1/KIF23, and A. nidulans BimC/KIF8). KIFC1 knockdown by siRNA or functional inhibition by AZ82 (0.4 to 1.2 µM) is shown to result in mitotic delay and multipolar spindle formation among BT549 population with extra centrosomes due to failure of chromosomes clustering. In cells with normal/two centrosomes, Eg5 inhibition causes monopolar spindles formation, while AZ82 co-treatment (400 nM) offsets the effect of Eg5 inhibition (5 nM AZD4877) and restores bipolar spindles phenotype in mitotic HeLa cells. Off-target cytotoxicity is reported when used at concentrations above 4 µM.

A moderately brain permeant, non-choline based isoxazolylbenzamide compound that acts as a highly selective and potent inhibitor of high-affinity choline transporter (CHT; K_i = 92 nM in hCHT-LV-AA transfected HEK293 cells and 166 nM in mouse brain synaptosomes). The inhibition appears to be allosteric and noncompetitive. Does not affect the activity of acetylcholinesterase or cholineacetyltransferase and has no activity against dopamine, serotonin, and norepinephrine transporters. Also does not affect CHT protein expression. Exhibits high selectivity when tested against 68 GPCRs, ion channels, and transporters (IC₅₀ >10 µM). Displays moderate pharmacokinetic properties (t_1/2= 33 min, AUC = 77.5 ng/h/ml; C_max = 32.6 ng/ml, at 2.3 mg/kg, p.o. in Sprague-Dawley rats) and attractive solubility (98.2 µM in PBS). Does not affect the activity of cytochrome P450 and hERG (IC₅₀ >30 µM).

Cell permeable: yes

Primary Target
CHT

Reversible: yes

Packaged under inert gas

Toxicity: Standard Handling (A)

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C.

Ennis, E.A., et al. ACS Chem. Neurosci.6, In press.

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