EMD638683

EMD638683 is a highly selective inhibitor of the serum and glucocorticoid inducible kinase (SGK) with IC50 value of 3 μM [1].
SGK is a group of serine/threonine kinases that consists of SGK1, SGK2 and SGK3. Among these, SGK1 takes participate in the signaling pathway that regulates the sodium channel, cell proliferation, cell survival and many other cellular processes. The transcription of SGK1 can be up-regulated by the activation of serum, mineralocorticoids and glucocorticoids. SGK1 enhanced the renal tubular reabsorption of sodium after the high salt activation. Besides that, SGK is highly expressed in some sorts of tumors while down-regulated in some other tumors such as APC. The selective SGK1 inhibitor EMD638683 showed inhibition effects on all the three forms of SGK but not for other kinases. It can affect the phosphorylation of NDRG1in vitro and meanwhile exert anti-tumor or anti-hypertensive efficacy in vivo [1, 2].
In the biochemical kinase assays, EMD638683 at concentration of 1 μM inhibited 85%, 71% and 75% activities of SGK1, SGK2 and SGK3, respectively. It also had inhibitory effects on MSK1 (mitogen-and stress-activated protein kinase 1) and PRK2 (protein kinase C-related kinase 2) with IC50 values of ≤ 1 μM. For other 64 kinases, such as MAPK, PRAK and Syk, EMD638683 showed no significant inhibition. In HeLa cells, EMD638683 suppressed the phosphorylation of NDRG1, which is a target of SGK1, with IC50 value of 3.35 μM. Besides that, EMD638683 treated CaCo-2 cells displayed increased depolarized mitochondria and enhanced caspase activity after the exposure to radiation [1, 2].
In mice treated with the carcinogenic drugs, the administration of EMD638683 at dose of 600 mg/kg/day significantly lowered the colon weight and reduced the developing tumors. In another mice experiment, administration of EMD638683 increased the urinary output and normalized the systolic blood pressure in mice treated with 10% fructose drinking water. It indicated that EMD638683 might be an attracted drug for the hypertension treatment in diabetic patients [1, 2].
References:
[1] Towhid S T, Liu G L, Ackermann T F, et al. Inhibition of colonic tumor growth by the selective SGK inhibitor EMD638683. Cellular physiology and biochemistry: international journal of experimental cellular physiology, biochemistry, and pharmacology, 2012, 32(4): 838-848.
[2] Ackermann T F, Boini K M, Beier N, et al. EMD638683, a novel SGK inhibitor with antihypertensive potency. Cellular Physiology and Biochemistry, 2011, 28(1): 137-146.

Inhibition of colonic tumor growth by the selective SGK inhibitor EMD638683.[Pubmed:24081014]

Cell Physiol Biochem. 2013;32(4):838-48.

BACKGROUND: The serum and glucocorticoid inducible kinase SGK1, which was originally cloned from mammary tumor cells, is highly expressed in some but not all tumors. SGK1 confers survival to several tumor cells. Along those lines, the number of colonic tumors following chemical carcinogenesis was decreased in SGK1 knockout mice. Recently, a highly selective SGK inhibitor (EMD638683) has been developed. The present study explored whether EMD638683 affects survival of colon carcinoma cells in vitro and impacts on development of colonic tumors in vivo. METHODS: Colon carcinoma (Caco-2) cells were exposed to EMD638683 with or without exposure to radiation (3 Gray) and cell volume was estimated from forward scatter, phosphatidylserine exposure from annexin V binding, mitochondrial potential from JC-9 fluorescence, caspase 3 activity from CaspGlow Fluorescein staining, DNA degradation from propidium iodide staining as well as late apoptosis from annexin-V FITC and propidium iodide double staining. In vivo tumor growth was determined in wild type mice subjected to chemical carcinogenesis (intraperitoneal injection of 20 mg/kg 1,2-dimethylhydrazine followed by three cycles of 30 g/L synthetic dextran sulfate sodium in drinking water for 7 days). RESULTS: EMD638683 treatment significantly augmented the radiation-induced decrease of forward scatter, increase of phosphatidylserine exposure, decrease of mitochondrial potential, increase of caspase 3 activity, increase of DNA fragmentation and increase of late apoptosis. The in vivo development of tumors following chemical carcinogenesis was significantly blunted by treatment with EMD638683. CONCLUSIONS: EMD638683 promotes radiation-induced suicidal death of colon tumor cells in vitro and decreases the number of colonic tumors following chemical carcinogenesis in vivo.

EMD638683, a novel SGK inhibitor with antihypertensive potency.[Pubmed:21865856]

Cell Physiol Biochem. 2011;28(1):137-46.

UNLABELLED: The serum- and glucocorticoid-inducible kinase 1 (SGK1) is transcriptionally upregulated by mineralocorticoids and activated by insulin. The kinase enhances renal tubular Na(+)-reabsorption and accounts for blood pressure increase following high salt diet in mice made hyperinsulinemic by dietary fructose or fat. The present study describes the in vitro and in vivo efficacy of a novel SGK1 inhibitor (EMD638683). EMD638683 was tested in vitro by determination of SGK1-dependent phosphorylation of NDRG1 (N-Myc downstream-regulated gene 1) in human cervical carcinoma HeLa-cells. In vivo EMD638683 (4460 ppm in chow, i.e. approx. 600 mg/kg/day) was administered to mice drinking tap water or isotonic saline containing 10% fructose. Blood pressure was determined by the tail cuff method, and urinary electrolyte (flame photometry) concentrations determined in metabolic cages. In vitro testing disclosed EMD638683 as a SGK1 inhibitor with an IC50 of 3 muM. Within 24 hours in vivo EMD638683 treatment significantly decreased blood pressure in fructose/saline-treated mice but not in control animals or in SGK1 knockout mice. EMD638683 failed to alter the blood pressure in SGK1 knockout mice. Following chronic (4 weeks) fructose/high salt treatment, additional EMD638683 treatment again decreased blood pressure. EMD638683 thus abrogates the salt sensitivity of blood pressure in hyperinsulinism without appreciably affecting blood pressure in the absence of hyperinsulinism. EMD638683 tended to increase fluid intake and urinary excretion of Na(+), significantly increased urinary flow rate and significantly decreased body weight. CONCLUSION: EMD638683 could serve as a template for drugs counteracting hypertension in individuals with type II diabetes and metabolic syndrome.