The complex [RuCp(PPh3)2(HdmoPTA)](OSO2CF3)2 (2; HdmoPTA = 3,7-H-3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) was synthesized and characterized. Its crystal structure was determined by single-crystal X-ray diffraction. The complex showed a more potent antiproliferative activity than cisplatin against a representative panel of human cancer cells.
Approaches to control epilepsy, one of the most important idiopathic brain disorders, are of great importance for public health. We have previously shown that in sympathetic neurons the neuronal isoform of the serum and glucocorticoid-regulated kinase (SGK1.1) increases the M-current, a well-known target for seizure control. The effect of SGK1.1 activation on kainate-induced seizures and neuronal excitability was studied in transgenic mice that express a permanently active form of the kinase, using electroencephalogram recordings and electrophysiological measurements in hippocampal brain slices. Our results demonstrate that SGK1.1 activation leads to reduced seizure severity and lower mortality rates following status epilepticus, in an M-current–dependent manner. EEG is characterized by reduced number, shorter duration, and early termination of kainate-induced seizures in the hippocampus and cortex. Hippocampal neurons show decreased excitability associated to increased M-current, without altering basal synaptic transmission or other neuronal properties. Altogether, our results reveal a novel and selective anticonvulsant pathway that promptly terminates seizures, suggesting that SGK1.1 activation can be a potent factor to secure the brain against permanent neuronal damage associated to epilepsy.
In the current study, we explored for the first time, the mechanism of action of the new Casein kinase 1 ε (CK1ε) selective inhibitor GSD0054. Although GSD0054 behaved as a selective CK1ε inhibitor in enzymatic assays, we studied whether this inhibitory activity also occurred inside the cells. The effects of GSD0054 on β -catenin expression and disruption of cell cycle progression were studied in the human breast cancer cell lines MDA-MB-453 (β -catenin negative) and T-47D (β -catenin positive). We also performed molecular modeling studies using computational docking against CK1ε to explain and predict the mechanism of action of this compound. Moreover, the commercially available CK1ε inhibitor PF-4800567 and the CK1δ /ε inhibitors PF-670462 and IC261 were also studied for comparison purposes. GSD0054 showed anti-proliferative activity against MDA-MB-453 and T-47D cells despite the fact that MDA-MB-453 cells do not possess active β -catenin. However, selective cell killing occurred in the more resistant, β -catenin active, T-47D cells. CK1ε was confirmed as a cellular target, although other targets or alternative mechanisms of action could possibly explain the anti-proliferative activity in MDA-MB-453 cells.
In the central nervous system, the M-current plays a critical role in regulating subthreshold electrical excitability of neurons, determining their firing properties and responsiveness to synaptic input. The M-channel is mainly formed by subunits Kv7.2 and Kv7.3 that co-assemble to form a heterotetrametric channel. Mutations in Kv7.2 and Kv7.3 are associated with hyperexcitability phenotypes including benign familial neonatal epilepsy (BFNE) and neonatal epileptic encephalopathy (NEE). SGK1.1, the neuronal isoform of the serum and glucocorticoids-regulated kinase 1 (SGK1), increases M-current density in neurons, leading to reduced excitability and protection against seizures. Herein, using two-electrode voltage clamp on Xenopus laevis oocytes, we demonstrate that SGK1.1 selectively activates heteromeric Kv7 subunit combinations underlying the M-current. Importantly, activated SGK1.1 increases M-channel activity in the presence of two different epilepsy mutations found in Kv7.2, R207W and A306T. In addition, proximity ligation assays in the N2a cell line allowed us to address the effect of these mutations on Kv7-SGK1.1-Nedd4 molecular associations, a proposed pathway underlying augmentation of M-channel activity by SGK1.1
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