Method and compounds

Details Method and compounds Method and compounds

2003-05-28

2004-04-13

McKane, Joseph K. (Department: 1626)

Material or article handling

Device for emptying portable receptacle

Upending

C548S546000, C548S547000

Reexamination Certificate

active

06719520

ABSTRACT:

This invention relates to a novel method for the treatment and/or prophylaxis of conditions associated with a need for inhibition of glycogen synthase kinase-3 (GSK-3), especially diabetes, including chronic neurodegenerative conditions, including dementias such as Alzheimer's disease, neurotraumatic diseases, such as acute stroke, mood disorders such as schizophrenia and manic depression, and for the treatment and/or prophylaxis of hair loss and cancer, and to certain novel inhibitors of GSK-3 for use in such a method.
GSK-3 is a serine/threonine protein kinase composed of two isoforms (&agr; and &bgr;) which are encoded by distinct genes. GSK-3 is one of several protein kinases which phosphorylates glycogen synthase (GS) (Embi et al Eur. J. Biochem. (107) 519-527 (1980)). The &agr; and &bgr; isoforms have a monomeric structure of 49 and 47 kD respectively and are both found in mammalian cells. Both isoforms phosphorylate muscle glycogen synthase (Cross et al Biochemical Journal (303) 21-26 (1994)) and these two isoforms show good homology between species (e.g. human and rabbit GSK-3&agr; are 96% identical).
Type II diabetes (or Non-Insulin Dependent Diabetes Mellitus, NIDDM) is a multifactorial disease. Hyperglycaemia is due to insulin resistance in the liver, muscle and other tissues coupled with inadequate or defective secretion of insulin from pancreatic islets. Skeletal muscle is the major site for insulin-stimulated glucose uptake and in this tissue, glucose removed from the circulation is either metabolised through glycolysis and the TCA cycle, or stored as glycogen. Muscle glycogen deposition plays the more important role in glucose homeostasis and Type II diabetic subjects have defective muscle glycogen storage.
The stimulation of glycogen synthesis by insulin in skeletal muscle results from the dephosphorylation and activation of glycogen synthase (Villar-Palasi C. and Lamer J. Biochim. Biophys. Acta (39) 171-173 (1960), Parker P J et al. Eur. J. Biochem. (130) 227-234 (1983), and Cohen P. Biochem. Soc. Trans. (21) 555-567 (1993)). The phosphorylation and dephosphorylation of GS are mediated by specific kinases and phosphatases. GSK-3 is responsible for phosphorylation and deactivation of GS, while glycogen bound protein phosphatase 1 (PP1G) dephosphorylates and activates GS. Insulin both inactivates GSK-3 and activates PP1G (Srivastava A K and Pandey S K Mol. and Cellular Biochem. (182) 135-141 (1998)).
Chen et al. Diabetes (43) 1234-1241 (1994) found that there was no difference in the mRNA abundance of PP1G between patients with Type II diabetes and control patients, suggesting that an increase in GSK-3 activity might be important in Type II diabetes. It has also recently been demonstrated that GSK-3 is overexpressed in Type II diabetic muscle and that an inverse correlation exists between skeletal muscle GSK-3&agr; activity and insulin action (Nikoulina et al Glycogen Synthase Kinase-3 in Human Skeletal Muscle: Relationship To Insulin Resistance in Type II Diabetes. Diabetes (47(1)) 0028 Page A7 (1998) (Oral presentation)). Overexpression of GSK-3&bgr; and constitutively active GSK-3&bgr; (S9A, S9E) mutants in HEK-293 cells resulted in supression of glycogen synthase activity (Eldar-Finkelman et al., PNAS (93) 10228-10233 (1996)) and overexpression of GSK-3&bgr; in CHO cells, expressing both insulin receptor and insulin receptor substrate 1 (IRS-1), resulted in an impairment of insulin action (Eldar-Finkelman and Krebs PNAS (94) 9660-9664 (1997)). Recent evidence for the involvement of elevated GSK-3 activity and the development of insulin resistance and type II diabetes in adipose tissue has emerged from studies undertaken in diabetes and obesity prone C57BL/6J mice (Eldar-Finkelman et al., Diabetes (48) 1662-1666 (1999)).
GSK-3 has been shown to phosphorylate other proteins in vitro including the eukaryotic initiation factor eIF-2B at Serine
540
(Welsh et al., FEBS Letts (421) 125-130 (1998)). This phosphorylation results in an inhibition of eIF-2B activity and leads to a reduction in this key regulatory step of translation. In disease states, such as diabetes, where there is elevated GSK-3 activity this could result in a reduction of translation and potentially contribute to the pathology of the disease.
Several aspects of GSK-3 functions and regulation in addition to modulation of glycogen synthase activity indicate that inhibitors of this enzyme may be effective in treatment of disorders of the central nervous system. GSK-3 activity is subject to inhibitory phosphorylation by PI 3 kinase-mediated or Wnt-1 class-mediated signals that can be mimicked by treatment with lithium, a low mM inhibitor of GSK-3 (Stambolic V., Ruel L. and Woodgett J. R Curr. Biol. 1996 6(12): 1664-8).
GSK-3 inhibitors may be of value as neuroprotectants in treatment of acute stroke and other neurotraumatic injuries. Roles for PI 3-kinase signalling through PKB/akt to promote neuronal cell survival are well established, and GSK-3 is one of a number of PKB/akt substrates to be identified that can contribute to the inhibition of apoptosis via this pathway (Pap & Cooper, (1998) J. Biol. Chem. 273: 19929-19932). Evidence suggests that astrocytic glycogen can provide an alternative energy source to facilitate neuronal survival under conditions of glucose deprivation (for example see Ransom, B. R. and Fern, R. (1997) Glia 21: 134-141 and references therein). Lithium is known to protect cerebellar granule neurons from death (D'Mello et al., (994) Exp. Cell Res. 211: 332-338 and Volonte et al (1994) Neurosci. Letts. 172: 6-10) and chronic lithium treatment has demonstrable efficacy in the middle cerebral artery occlusion model of stroke in rodents (Nonaka and Chuang, (1998) Neuroreport 9(9): 2081-2084). Wnt-induced axonal spreading and branching in neuronal culture models has been shown to correlate with GSK-3 inhibition (Lucas & Salinas. (1997) Dev. Biol. 192: 31-44) suggesting additional value of GSK-3 inhibitors in promoting neuronal regeneration following neurotraumatic insult.
Tau and &bgr;-catenin, two known in vivo substrates of GSK-3, are of direct relevance in consideration of further aspects of the value of GSK-3 inhibitors in relation to treatment of chronic neurodegenerative conditions. Tau hyperphosphorylation is an early event in neurodegenerative conditions such as Alzheimer's disease (AD), and is postulated to promote microtubule disassembly. Lithium has been reported to reduce the phosphorylation of tau, enhance the binding of tau to microtubules, and promote microtubule assembly through direct and reversible inhibition of glycogen synthase kinase-3 (Hong M., Chen D. C., Klein P. S. and Lee V. M. J. Biol. Chem. 1997 272(40) 25326-32). &bgr;-catenin is phosphorylated by GSK-3 as part of a tripartite complex with axin, resulting in &bgr;-catenin being targetted for degradation (Ikeda el al., (1998) EMBO J. 17: 1371-1384). Inhibition of GSK-3 activity is a key mechanism by which cytosolic levels of catenin are stabilised and hence promote &bgr;-catenin-LEF-1/TCF transcriptional activity (Eastman, Grosschedl (1999) Curr. Opin. Cell Biol. 11: 233). Rapid onset AD mutations in presenilin-1 (PS-1) have been shown to decrease the cytosolic &bgr;-catenin pool in transgenic mice. Further evidence suggests that such a reduction in available &bgr;-catenin may increase neuronal sensitivity to amyloid mediated death through inhibition of &bgr;-catenin-LEF-1/TCF transcriptional regulation of neutoprotective genes (Zhang et al., (1998) Nature 395: 698-702). A likely mechanism is suggested by the finding that mutant PS-1 protein confers decreased inactivation of GSK-3 compared with normal PS-1 (Weihl, C. C., Ghadge, G. D., Kennedy, S. G., Hay, N., Miller, R. J. and Roos, R. P.(1999) J. Neurosci. 19: 5360-5369).
WO 97/41854 (University of Pennsylvania) discloses that an effective drug for the treatment of manic depression is lithium but that there are serious drawbacks associated with this treatment. Whilst the precise mechanism of action of this drug for treatment of manic de

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