Akt inhibitor A-443654 induces rapid Akt Ser-473 phosphorylation independent of mTORC1 inhibition

被引:143
作者
Han, E. K-H
Leverson, J. D.
McGonigal, T.
Shah, O. J.
Woods, K. W.
Hunter, T.
Giranda, V. L.
机构
[1] Abbott Labs, Global Pharmaceut Res Div, Abbott Pk, IL 60064 USA
[2] Salk Inst Biol Studies, Mol & Cell Biol Lab, La Jolla, CA 92037 USA
关键词
A-443654; Akt; phosphorylation; rapamycin; mTOR;
D O I
10.1038/sj.onc.1210343
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Rapamycin, a natural product inhibitor of the Raptor-mammalian target of rapamycin complex (mTORC1), is known to induce Protein kinase B (Akt/PKB) Ser-473 phosphorylation in a subset of human cancer cell lines through inactivation of S6K1, stabilization of insulin receptor substrate (IRS)-1, and increased signaling through the insulin/insulin-like growth factor-I/phosphatidylinositol 3-kinase (PI3K) axis. We report that A-443654, a potent small-molecule inhibitor of Akt serine/threonine kinases, induces Akt Ser-473 phosphorylation in all human cancer cell lines tested, including PTEN- and TSC2-deficient lines. This phenomenon is dose-dependent, manifests coincident with Akt inhibition and likely represents an alternative, rapid-feedback pathway that can be functionally dissociated from mTORC1 inhibition. Experiments performed in TSC2(-/-) cells indicate that TSC2 and IRS-1 cooperate with, but are dispensable for, A-443654-mediated Akt phosphorylation. This feedback event does require PI3K activity, however, as it can be inhibited by LY294002 or wortmannin. Small interfering RNA-mediated knockdown of mTOR or Rictor, components of the rapamycin-insensitive mTORC2 complex, but not the mTORC1 component Raptor, also inhibited Akt Ser-473 phosphorylation induced by A-443654. Our data thus indicate that Akt phosphorylation and activity are coupled in a manner not previously appreciated and provide a novel mode of Akt regulation that is distinct from the previously described rapamycin-induced IRS-1 stabilization mechanism.
引用
收藏
页码:5655 / 5661
页数:7
相关论文
共 27 条
[1]   Characterization of a 3-phosphoinositide-dependent protein kinase which phosphorylates and activates protein kinase B alpha [J].
Alessi, DR ;
James, SR ;
Downes, CP ;
Holmes, AB ;
Gaffney, PRJ ;
Reese, CB ;
Cohen, P .
CURRENT BIOLOGY, 1997, 7 (04) :261-269
[2]   Perturbations of the AKT signaling pathway in human cancer [J].
Altomare, DA ;
Testa, JR .
ONCOGENE, 2005, 24 (50) :7455-7464
[3]   PDK1 acquires PDK2 activity in the presence of a synthetic peptide derived from the carboxyl terminus of PRK2 [J].
Balendran, A ;
Casamayor, A ;
Deak, M ;
Paterson, A ;
Gaffney, P ;
Currie, R ;
Downes, CP ;
Alessi, DR .
CURRENT BIOLOGY, 1999, 9 (08) :393-404
[4]   The Akt/PKB family of protein kinases: A review of small molecule inhibitors and progress towards target validation [J].
Barnett, SF ;
Bilodeau, MT ;
Lindsley, CW .
CURRENT TOPICS IN MEDICINAL CHEMISTRY, 2005, 5 (02) :109-125
[5]   Direct inhibition of the signaling functions of the mammalian target of rapamycin by the phosphoinositide 3-kinase inhibitors, wortmannin and LY294002 [J].
Brunn, GJ ;
Williams, J ;
Sabers, C ;
Wiederrecht, G ;
Lawrence, JC ;
Abraham, RT .
EMBO JOURNAL, 1996, 15 (19) :5256-5267
[6]   The Akt/PKB pathway: molecular target for cancer drug discovery [J].
Cheng, JQ ;
Lindsley, CW ;
Cheng, GZ ;
Yang, H ;
Nicosia, SV .
ONCOGENE, 2005, 24 (50) :7482-7492
[7]   Feedback control of the protein kinase TAK1 by SAPK2a/p38α [J].
Cheung, PCF ;
Campbell, DG ;
Nebreda, AR ;
Cohen, P .
EMBO JOURNAL, 2003, 22 (21) :5793-5805
[8]   Cellular survival: a play in three Akts [J].
Datta, SR ;
Brunet, A ;
Greenberg, ME .
GENES & DEVELOPMENT, 1999, 13 (22) :2905-2927
[9]   Specificity and mechanism of action of some commonly used protein kinase inhibitors [J].
Davies, SP ;
Reddy, H ;
Caivano, M ;
Cohen, P .
BIOCHEMICAL JOURNAL, 2000, 351 (351) :95-105
[10]   Identification of a PKB/Akt hydrophobic motif Ser-473 kinase as DNA-dependent protein kinase [J].
Feng, JH ;
Park, J ;
Cron, P ;
Hess, D ;
Hemmings, BA .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2004, 279 (39) :41189-41196