Cell-permeable dual inhibitors of protein kinases CK2 and PIM-1: structural features and pharmacological potential

It has been proposed that dual inhibitors of protein kinases CK2 and PIM-1 are tools particularly valuable to induce apoptosis of cancer cells, a property, however, implying cell permeability, which is lacking in the case of selective CK2/PIM-1 inhibitors developed so far. To fill this gap, we have derivatized the scaffold of the promiscuous CK2 inhibitor TBI with a deoxyribose moiety, generating TDB, a selective, cell-permeable inhibitor of CK2 and PIM-1. Here, we shed light on the structural features underlying the potency and narrow selectivity of TDB by exploiting a number of TDB analogs and by solving the 3D structure of the TDB/CK2 complex at 1.25?Å resolution, one of the highest reported so far for this kinase. We also show that the cytotoxic efficacy of TDB is almost entirely due to apoptosis, is accompanied by parallel inhibition of cellular CK2 and PIM-1, and is superior to both those observed combining individual inhibitors of CK2 and PIM-1 and by treating cells with the CK2 inhibitor CX4945. These data, in conjunction with the observations that cancer cells are more susceptible than non-cancer cells to TDB and that such a sensitivity is maintained in a multi-drug resistance background, highlight the pharmacological potential of this compound.     

Vanilloid receptors on sensory nerves mediate the vasodilator action of anandamide.

The endogenous cannabinoid receptor agonist anandamide is a powerful vasodilator of isolated vascular preparations, but its mechanism of action is unclear. Here we show that the vasodilator response to anandamide in isolated arteries is capsaicin-sensitive and accompanied by release of calcitonin-gene-related peptide (CGRP). The selective CGRP-receptor antagonist 8-37 CGRP, but not the cannabinoid CB1 receptor blocker SR141716A, inhibited the vasodilator effect of anandamide. Other endogenous (2-arachidonylglycerol, palmitylethanolamide) and synthetic (HU 210, WIN 55,212-2, CP 55,940) CB1 and CB2 receptor agonists could not mimic the action of anandamide. The selective 'vanilloid receptor' antagonist capsazepine inhibited anandamide-induced vasodilation and release of CGRP. In patch-clamp experiments on cells expressing the cloned vanilloid receptor (VR1), anandamide induced a capsazepine-sensitive current in whole cells and isolated membrane patches. Our results indicate that anandamide induces vasodilation by activating vanilloid receptors on perivascular sensory nerves and causing release of CGRP. The vanilloid receptor may thus be another molecular target for endogenous anandamide, besides cannabinoid receptors, in the nervous and cardiovascular systems.     

Mustard oils and cannabinoids excite sensory nerve fibres through the TRP channel ANKTM1

Wasabi, horseradish and mustard owe their pungency to isothiocyanate compounds. Topical application of mustard oil (allyl isothiocyanate) to the skin activates underlying sensory nerve endings, thereby producing pain, inflammation and robust hypersensitivity to thermal and mechanical stimuli. Despite their widespread use in both the kitchen and the laboratory, the molecular mechanism through which isothiocyanates mediate their effects remains unknown. Here we show that mustard oil depolarizes a subpopulation of primary sensory neurons that are also activated by capsaicin, the pungent ingredient in chilli peppers, and by Delta(9)-tetrahydrocannabinol (THC), the psychoactive component of marijuana. Both allyl isothiocyanate and THC mediate their excitatory effects by activating ANKTM1, a member of the TRP ion channel family recently implicated in the detection of noxious cold. These findings identify a cellular and molecular target for the pungent action of mustard oils and support an emerging role for TRP channels as ionotropic cannabinoid receptors.