1.DW09849, a selective phosphatidylinositol 3-kinase (PI3K) inhibitor, prevents PI3K signaling and preferentially inhibits proliferation of cells containing the oncogenic mutation p110α (H1047R).
Liu JL1, Gao GR, Zhang X, Cao SF, Guo CL, Wang X, Tong LJ, Ding J, Duan WH, Meng LH. J Pharmacol Exp Ther. 2014 Mar;348(3):432-41. doi: 10.1124/jpet.113.210724. Epub 2013 Dec 20.
Phosphatidylinositol 3-kinase, α isoform (PI3Kα) plays essential roles in cell metabolism, growth, and proliferation and has been validated as a promising anticancer target. In an effort to search for new PI3Kα-selective inhibitors, DW series compounds were designed and synthesized aiming to reduce the off-target effects of their parent compound PIK-75 [2-methyl-5-nitro-1-benzenesulfonic acid 2-[(6-bromoimidazo[1,2-a]pyridin-3-yl)methylene]-1-methylhydrazide], which was reported to selectively target PI3Kα. A series of compounds named DW series potently inhibited the kinase activity of PI3Kα with little activity against PI3K-related protein kinases and a panel of 15 tyrosine kinases. Similar to PIK-75, DW series compounds were more potent to inhibit PI3Kα among four class I PI3K isoforms, whereas a representative compound DW09849 [(E)-N'-((6-bromoimidazo[1,2-a]pyridin-3-yl)methylene)-N-ethyl-2-methyl-5-nitrobenzohydrazide] displayed distinct binding mode compared with PIK-75.
2.Genetic and pharmacological evidence that G2019S LRRK2 confers a hyperkinetic phenotype, resistant to motor decline associated with aging.
Longo F1, Russo I2, Shimshek DR3, Greggio E2, Morari M4. Neurobiol Dis. 2014 Nov;71:62-73. doi: 10.1016/j.nbd.2014.07.013. Epub 2014 Aug 6.
The leucine-rich repeat kinase 2 mutation G2019S in the kinase-domain is the most common genetic cause of Parkinson's disease. To investigate the impact of the G2019S mutation on motor activity in vivo, a longitudinal phenotyping approach was developed in knock-in (KI) mice bearing this kinase-enhancing mutation. Two cohorts of G2019S KI mice and wild-type littermates (WT) were subjected to behavioral tests, specific for akinesia, bradykinesia and overall gait ability, at different ages (3, 6, 10, 15 and 19months). The motor performance of G2019S KI mice remained stable up to the age of 19months and did not show the typical age-related decline in immobility time and stepping activity of WT. Several lines of evidence suggest that enhanced LRRK2 kinase activity is the main contributor to the observed hyperkinetic phenotype of G2019S KI mice: i) KI mice carrying a LRRK2 kinase-dead mutation (D1994S KD) showed a similar progressive motor decline as WT; ii) two LRRK2 kinase inhibitors, H-1152 and Nov-LRRK2-11, acutely reversed the hyperkinetic phenotype of G2019S KI mice, while being ineffective in WT or D1994S KD animals.
3.Mutational analysis of cysteine residues of the insect odorant co-receptor (Orco) from Drosophila melanogaster reveals differential effects on agonist- and odorant-tuning receptor-dependent activation.
Turner RM1, Derryberry SL2, Kumar BN1, Brittain T1, Zwiebel LJ2, Newcomb RD3, Christie DL4. J Biol Chem. 2014 Nov 14;289(46):31837-45. doi: 10.1074/jbc.M114.603993. Epub 2014 Sep 30.
Insect odorant receptors are heteromeric odorant-gated cation channels comprising a conventional odorant-sensitive tuning receptor (ORx) and a highly conserved co-receptor known as Orco. Orco is found only in insects, and very little is known about its structure and the mechanism leading to channel activation. In the absence of an ORx, Orco forms homomeric channels that can be activated by a synthetic agonist, VUAA1. Drosophila melanogaster Orco (DmelOrco) contains eight cysteine amino acid residues, six of which are highly conserved. In this study, we replaced individual cysteine residues with serine or alanine and expressed Orco mutants in Flp-In 293 T-Rex cells. Changes in intracellular Ca(2+) levels were used to determine responses to VUAA1. Replacement of two cysteines (Cys-429 and Cys-449) in a predicted intracellular loop (ICL3), individually or together, gave variants that all showed similar increases in the rate of response and sensitivity to VUAA1 compared with wild-type DmelOrco.
4.Effect of selective LRRK2 kinase inhibition on nonhuman primate lung.
Fuji RN1, Flagella M2, Baca M3, Baptista MA4, Brodbeck J2, Chan BK5, Fiske BK4, Honigberg L6, Jubb AM3, Katavolos P2, Lee DW2, Lewin-Koh SC7, Lin T2, Liu X8, Liu S2, Lyssikatos JP5, O'Mahony J2, Reichelt M3, Roose-Girma M9, Sheng Z10, Sherer T4, Smith A6, Solon M3, Sweeney ZK5, Tarrant J2, Urkowitz A4, Warming S9, Yaylaoglu M3, Zhang S10, Zhu H10, Estrada AA5, Watts RJ11. Sci Transl Med. 2015 Feb 4;7(273):273ra15. doi: 10.1126/scitranslmed.aaa3634.
Inhibition of the kinase activity of leucine-rich repeat kinase 2 (LRRK2) is under investigation as a possible treatment for Parkinson's disease. However, there is no clinical validation as yet, and the safety implications of targeting LRRK2 kinase activity are not well understood. We evaluated the potential safety risks by comparing human and mouse LRRK2 mRNA tissue expression, by analyzing a Lrrk2 knockout mouse model, and by testing selective brain-penetrating LRRK2 kinase inhibitors in multiple species. LRRK2 mRNA tissue expression was comparable between species. Phenotypic analysis of Lrrk2 knockout mice revealed morphologic changes in lungs and kidneys, similar to those reported previously. However, in preclinical toxicity assessments in rodents, no pulmonary or renal changes were induced by two distinct LRRK2 kinase inhibitors. Both of these kinase inhibitors induced abnormal cytoplasmic accumulation of secretory lysosome-related organelles known as lamellar bodies in type II pneumocytes of the lung in nonhuman primates, but no lysosomal abnormality was observed in the kidney.
