Substantial evidence implicates -amyloid (A ) peptides in the etiology of Alzheimer’s disease (AD). A is produced by the proteolytic cleavage of the amyloid precursor protein by - and -secretase suggesting that -secretase inhibition may provide therapeutic benefit for AD. Although many -secretase inhibitors have been shown to be potent at lowering A , some have also been shown to have side effects following repeated administration. All of these side effects can be attributed to altered Notch signaling, another -secretase substrate. Here we describe the in vivo characterization of the novel -secretase inhibitor SCH 697466 in rodents. Although SCH 697466 was effective at lowering A , Notch-related side effects in the intestine and thymus were observed following subchronic administration at doses that provided sustained and complete lowering of A . However, additional studies revealed that both partial but sustained lowering of A and complete but less sustained lowering of A were successful approaches for managing Notch-related side effects. Further, changes in several Notch-related biomarkers paralleled the side effect observations. Taken together, these studies demonstrated that, by carefully varying the extent and duration of A lowering by -secretase inhibitors, it is possible to obtain robust and sustained lowering of A without evidence of Notch-related side effects. 1. Introduction Alzheimer’s disease (AD) is a progressive age-related neurodegenerative disease characterized clinically by memory loss and cognitive dysfunction followed by a disruption of normal daily functions, organ system failure, and, ultimately, death. However, a diagnosis of AD can only be confirmed postmortem by the presence of distinct neuroanatomical hallmarks including senile plaques consisting primarily of β-amyloid (Aβ) peptides, neurofibrillary tangles consisting of hyperphosphorylated tau, and substantial neuronal loss, particularly in the hippocampus, an area of the brain which plays a key role in memory. Substantial genetic and neuroanatomical evidence implicates Aβ peptides in the etiology of Alzheimer’s disease (e.g., [1–3]). Therefore, it is thought that a reduction in Aβ production or an increase in Aβ clearance will have a beneficial, and potentially disease modifying, effect on the disease. Aβ is produced by sequential cleavage of amyloid precursor protein (APP) by β-site APP cleaving enzyme 1 (BACE1) followed by γ-secretase. Thus, inhibiting γ-secretase should decrease Aβ production. Indeed, acute and chronic administration of small molecule γ-secretase inhibitors
References
[1]
D. J. Selkoe, “The molecular pathology of Alzheimer's disease,” Neuron, vol. 6, no. 4, pp. 487–498, 1991.
[2]
J. A. Hardy and G. A. Higgins, “Alzheimer's disease: the amyloid cascade hypothesis,” Science, vol. 256, no. 5054, pp. 184–185, 1992.
[3]
J. Hardy and D. J. Selkoe, “The amyloid hypothesis of Alzheimer's disease: progress and problems on the road to therapeutics,” Science, vol. 297, no. 5580, pp. 353–356, 2002.
[4]
D. M. Barten, J. E. Meredith Jr., R. Zaczek, J. G. Houston, and C. F. Albright, “γ-secretase inhibitors for Alzheimer's disease: balancing efficacy and toxicity,” Drugs in R and D, vol. 7, no. 2, pp. 87–97, 2006.
[5]
L. A. Hyde, N. A. McHugh, J. Chen et al., “Studies to investigate the in vivo therapeutic window of the γ-secretase inhibitor N2-[(2S)-2-(3,5-difluorophenyl)-2- hydroxyethanoyl]-N1-[(7S)-5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b,d] azepin-7-yl]-L-alaninamide (LY411,575) in the CRND8 mouse,” Journal of Pharmacology and Experimental Therapeutics, vol. 319, no. 3, pp. 1133–1143, 2006.
[6]
J. D. Best, M. T. Jay, F. Otu et al., “In vivo characterization of Aβ(40) changes in brain and cerebrospinal fluid using the novel γ-secretase inhibitor N-[cis-4-[(4-chlorophenyl)sulfonyl]-4-(2,5-difluorophenyl)cyclohexyl]-1,1,1- trifluoromethanesulfonamide (MRK-560) in the rat,” Journal of Pharmacology and Experimental Therapeutics, vol. 317, no. 2, pp. 786–790, 2006.
[7]
C. V. C. Prasad, M. Zheng, S. Vig et al., “Discovery of (S)-2-((S)-2-(3,5-difluorophenyl)-2-hydroxyacetamido)- N-((S,Z)-3-methyl-4-oxo-4,5-dihydro-3H-benzo[d][1,2]diazepin-5-yl)propanamide (BMS-433796): a γ-secretase inhibitor with Aβ lowering activity in a transgenic mouse model of Alzheimer's disease,” Bioorganic and Medicinal Chemistry Letters, vol. 17, no. 14, pp. 4006–4011, 2007.
[8]
R. L. Martone, H. Zhou, K. Atchison-, et al., “Begacestat (GSI-953): a novel, selective thiophene sulfonamide inhibitor of amyloid precursor protein gamma-secretase for the treatment of Alzheimer's disease,” Journal of Pharmacology and Experimental Therapeutics, vol. 331, no. 2, pp. 598–608, 2009.
[9]
K. W. Gillman, J. E. Starrett, M. F. Parker, et al., “Discovery and evaluation of BMS-708163, a potent, selective and orally bioavailable -Secretase Inhibitor,” ACS Medicinal Chemistry Letters, vol. 1, no. 3, p. 120, 2010.
[10]
G. S. Basi, S. Hemphill, E. F. Brigham, et al., “Amyloid precursor protein selective gamma-secretase inhibitors for treatment of Alzheimer's disease,” Alzheimer's Research & Therapy, vol. 2, no. 6, p. 36, 2010.
[11]
T. A. Lanz, K. M. Wood, K. E. G. Richter et al., “Pharmacodynamics and pharmacokinetics of the γ-secretase inhibitor PF-3084014,” Journal of Pharmacology and Experimental Therapeutics, vol. 334, no. 1, pp. 269–277, 2010.
[12]
Y. Mitani, J. Yarimizu, K. Saita et al., “Differential effects between gamma-secretase inhibitors and modulators on cognitive function in amyloid precursor protein-transgenic and nontransgenic mice,” Journal of Neuroscience, vol. 32, no. 6, pp. 2037–2050, 2012.
[13]
D. B. Henley, P. C. May, R. A. Dean, and E. R. Siemers, “Development of semagacestat (LY450139), a functional γ-secretase inhibitor, for the treatment of Alzheimer's disease,” Expert Opinion on Pharmacotherapy, vol. 10, no. 10, pp. 1657–1664, 2009.
[14]
R. J. Bateman, E. R. Siemers, K. G. Mawuenyega et al., “A γ-secretase inhibitor decreases amyloid-β production in the central nervous system,” Annals of Neurology, vol. 66, no. 1, pp. 48–54, 2009.
[15]
G. Tong, J. S. Wang, O. Sverdlov, et al., “Multicenter, randomized, double-blind, placebo-controlled, single-ascending dose study of the oral gamma-secretase inhibitor BMS-708163 (Avagacestat): tolerability profile, pharmacokinetic parameters, and pharmacodynamic markers,” Clinical Therapeutics, vol. 34, no. 3, pp. 654–667, 2012.
[16]
A. S. Fleisher, R. Raman, E. R. Siemers et al., “Phase 2 safety trial targeting amyloid beta production with a gamma-secretase inhibitor in Alzheimer disease,” Archives of Neurology, vol. 65, no. 8, pp. 1031–1038, 2008.
[17]
E. R. Siemers, J. F. Quinn, J. Kaye et al., “Effects of a γ-secretase inhibitor in a randomized study of patients with Alzheimer disease,” Neurology, vol. 66, no. 4, pp. 602–604, 2006.
[18]
J. D. Best, D. W. Smith, M. A. Reilly et al., “The novel γ secretase inhibitor N-[cis-4-[(4-chlorophenyl)sulfonyl]- 4-(2,5-difluorophenyl)cyclohexyl]-1,1,1-trifluoromethanesulfonamide (MRK-560) reduces amyloid plaque deposition without evidence of notch-related pathology in the Tg2576 mouse,” Journal of Pharmacology and Experimental Therapeutics, vol. 320, no. 2, pp. 552–558, 2007.
[19]
D. Abramowski, K. H. Wiederhold, U. Furrer et al., “Dynamics of Aβ turnover and deposition in different β-amyloid precursor protein transgenic mouse models following γ-secretase inhibition,” Journal of Pharmacology and Experimental Therapeutics, vol. 327, no. 2, pp. 411–424, 2008.
[20]
S. J. Pollack and H. Lewis, “γ-Secretase inhibitors for Alzheimer's disease: challenges of a promiscuous protease,” Current Opinion in Investigational Drugs, vol. 6, no. 1, pp. 35–47, 2005.
[21]
A. Lleo and C. A. Saura, “gamma-secretase substrates and their implications for drug development in Alzheimer's disease,” Current Topics in Medicinal Chemistry, vol. 11, no. 12, pp. 1513–1527, 2011.
[22]
B. De Strooper, W. Annaert, P. Cupers et al., “A presenilin-1-dependent γ-secretase-like protease mediates release of notch intracellular domain,” Nature, vol. 398, no. 6727, pp. 518–522, 1999.
[23]
S. Artavanis-Tsakonas, M. D. Rand, and R. J. Lake, “Notch signaling: cell fate control and signal integration in development,” Science, vol. 284, no. 5415, pp. 770–776, 1999.
[24]
D. C. Cole, J. R. Stock, A. F. Kreft et al., “(S)-N-(5-Chlorothiophene-2-sulfonyl)-β,β-diethylalaninol a Notch-1-sparing γ-secretase inhibitor,” Bioorganic and Medicinal Chemistry Letters, vol. 19, no. 3, pp. 926–929, 2009.
[25]
A. Kreft, B. Harrison, S. Aschmies et al., “Discovery of a novel series of Notch-sparing γ-secretase inhibitors,” Bioorganic and Medicinal Chemistry Letters, vol. 18, no. 14, pp. 4232–4236, 2008.
[26]
S. C. Mayer, A. F. Kreft, B. Harrison et al., “Discovery of begacestat, a Notch-1-sparing γ-secretase inhibitor for the treatment of Alzheimer's disease,” Journal of Medicinal Chemistry, vol. 51, no. 23, pp. 7348–7351, 2008.
[27]
G. H. Searfoss, W. H. Jordan, D. O. Calligaro et al., “Adipsin, a biomarker of gastrointestinal toxicity mediated by a functional gamma-secretase inhibitor,” Journal of Biological Chemistry, vol. 278, no. 46, pp. 46107–46116, 2003.
[28]
G. T. Wong, D. Manfra, F. M. Poulet et al., “Chronic treatment with the gamma-secretase inhibitor LY-411,575 inhibits beta-amyloid peptide production and alters lymphopoiesis and intestinal cell differentiation,” Journal of Biological Chemistry, vol. 279, no. 13, pp. 12876–12882, 2004.
[29]
J. Milano, J. McKay, C. Dagenais et al., “Modulation of Notch processing by γ-secretase inhibitors causes intestinal goblet cell metaplasia and induction of genes known to specify gut secretory lineage differentiation,” Toxicological Sciences, vol. 82, no. 1, pp. 341–358, 2004.
[30]
J. H. Van Es, M. E. Van Gijn, O. Riccio et al., “Notch/γ-secretase inhibition turns proliferative cells in intestinal crypts and adenomas into goblet cells,” Nature, vol. 435, no. 7044, pp. 959–963, 2005.
[31]
M. Katoh and M. Katoh, “Notch signaling in gastrointestinal tract (Review),” International Journal of Oncology, vol. 30, no. 1, pp. 247–251, 2007.
[32]
H. Zheng, D. M. Pritchard, X. Yang et al., “KLF4 gene expression is inhibited by the notch signaling pathway that controls goblet cell differentiation in mouse gastrointestinal tract,” American Journal of Physiology, vol. 296, no. 3, pp. G490–G498, 2009.
[33]
C. A. Richmond and D. T. Breault, “Regulation of gene expression in the intestinal epithelium,” Progress in Molecular Biology and Translational Science, vol. 96, pp. 207–229, 2010.
[34]
T. Asberom, Z. Zhao, T. A. Bara et al., “Discovery of γ-secretase inhibitors efficacious in a transgenic animal model of Alzheimer's disease,” Bioorganic and Medicinal Chemistry Letters, vol. 17, no. 2, pp. 511–516, 2007.
[35]
M. A. Chishti, D. S. Yang, C. Janus et al., “Early-onset amyloid deposition and cognitive deficits in transgenic mice expressing a double mutant form of amyloid precursor protein 695,” Journal of Biological Chemistry, vol. 276, no. 24, pp. 21562–21570, 2001.
[36]
L. A. Hyde, T. M. Kazdoba, M. Grilli et al., “Age-progressing cognitive impairments and neuropathology in transgenic CRND8 mice,” Behavioural Brain Research, vol. 160, no. 2, pp. 344–355, 2005.
[37]
T. A. Lanz, C. S. Himes, G. Pallante et al., “The γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-lalanyl]-S-phenylglycine t-butyl ester reduces Aβ levels in vivo in plasma and cerebrospinal fluid in young (plaque-free) and aged (plaque-bearing) Tg2576 mice,” Journal of Pharmacology and Experimental Therapeutics, vol. 305, no. 3, pp. 864–871, 2003.
[38]
D. M. Barten, V. L. Guss, J. A. Corsa et al., “Dynamics of β-amyloid reductions in brain, cerebrospinal fluid, and plasma of β-amyloid precursor protein transgenic mice treated with a γ-secretase inhibitor,” Journal of Pharmacology and Experimental Therapeutics, vol. 312, no. 2, pp. 635–643, 2005.
[39]
L. Zhang, L. Song, G. Terracina, Y. Liu, B. Pramanik, and E. Parker, “Biochemical characterization of the γ-secretase activity that produces β-amyloid peptides,” Biochemistry, vol. 40, no. 16, pp. 5049–5055, 2001.
[40]
C. R. Burton, J. E. Meredith, D. M. Barten et al., “The amyloid-β rise and γ-secretase inhibitor potency depend on the level of substrate expression,” Journal of Biological Chemistry, vol. 283, no. 34, pp. 22992–23003, 2008.
[41]
J. Jensen, E. E. Pedersen, P. Galante et al., “Control of endodermal endocrine development by Hes-1,” Nature Genetics, vol. 24, no. 1, pp. 36–44, 2000.
[42]
S. Fre, M. Huyghe, P. Mourikis, S. Robine, D. Louvard, and S. Artavanis-Tsakonas, “Notch signals control the fate of immature progenitor cells in the intestine,” Nature, vol. 435, no. 7044, pp. 964–968, 2005.
[43]
P. Das, C. Verbeeck, L. Minter et al., “Transient pharmacologic lowering of Abeta production prior to deposition results in sustained reduction of amyloid plaque pathology,” Molecular Neurodegeneration, vol. 7, p. 39, 2012.
[44]
T. A. Lanz, M. J. Karmilowicz, K. M. Wood et al., “Concentration-dependent modulation of amyloid-β in vivo and in vitro using the γ-secretase inhibitor, LY-450139,” Journal of Pharmacology and Experimental Therapeutics, vol. 319, no. 2, pp. 924–933, 2006.
[45]
E. Siemers, M. Skinner, R. A. Dean et al., “Safety, tolerability, and changes in amyloid β concentrations after administration of a γ-secretase inhibitor in volunteers,” Clinical Neuropharmacology, vol. 28, no. 3, pp. 126–132, 2005.
