Abstract
Aim:
To study the expression of proline-rich Akt-substrate PRAS40 in the cell survival pathway and tumor progression.
Methods:
The effects of three key kinase inhibitors on PRAS40 activity in the cell survival pathway, serum withdrawal, H2O2 and overexpression of Akt were tested. The expression of PRAS40, Akt, Raf and 14-3-3 in normal cells and cancer cell lines was determined by Western blot.
Results:
The PI3K inhibitors worthmannin and Ly294002, but not rapamycin, completely inhibited the phosphorylation of Akt and PRAS40. The phosphorylation level of Akt decreased after serum withdrawal and treatment with the MEK inhibitor Uo126, but increased after treatment with H2O2 at low concentration, whereas none of these treatments changed PRAS40 activity. 14-3-3 is a PRAS40 binding protein, nd the expression of 14-3-3, like that of PRAS40, was higher in HeLa cells than in HEK293 cells; PRAS40 had a stronger phosphorylation activity in A549 and HeLa cancer cells than in HEK293 normal cells. In the breast cancer model (MCF10A/MCF7) and lung cancer model (BEAS/H1198/H1170) we also found the same result: PRAS40 was constitutively active in H1198/H1170 and MCF7 premalignant and malignant cancer cells, but weakly expressed in MCF10A and BEAS normal cell. We also discussed PRAS40 activity in other NSCLC cell lines.
Conclusion:
The PI3K-Akt survival pathway is the main pathway that PRAS40 is involved in; PRAS40 is a substrate for Akt, but can also be activated by an Akt-independent mechanisms. PRAS40 activation is an early event during breast and lung carcinogenesis.
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References
Khuri FR, Herbst RS, Fossella FV . Emerging therapies in non-small-cell lung cancer. Ann Oncol 2001; 12: 739–44.
McWilliams A, Lam S . New approaches to lung cancer prevention. Curr Oncol Rep 2002; 4: 489–94.
Goodman GE . Lung cancer 1: prevention of lung cancer. Thorax 2002; 57: 994–9.
Hong WK, Sporn MB . Recent advances in chemoprevention of cancer. Science 1997; 278: 1073–7.
Vivanco I, Sawyers Cl . The phosphatidylinositol 3-kinase Akt pathway in human cancer. Nat Rev Cancer 2002; 2: 489–501.
Cantley LC . The phosphoinositide 3-kinase pathway. Science 2002; 296: 1655–7.
Manning BD, Cantley LC . United at last: the tuberous sclerosis complex gene products connect the phosphoinositide 3-kinase/Akt pathway to mammalian target of rapmycin (mTOR) signaling. Biochem Soc Trans 2003; 31: 573–8.
Kovacina KS, Park GY, Bea SK, Gruzzetta AW, Schaefer E, Birnbaum MJ . Identification of a proline-rich Akt substrate as a 14-3-3 binding partner. J Biol Chem 2003; 12: 10189–94.
Saito A, Narasimhan P, Hayashi T, Okuno S, Ferrand-Drake M, Chan PH . Neuroprotective role of a proline-rich Akt substrate in apoptotic neuronal cell death after Stroke: relationships with nerve growth factor. J Neurosci 2004; 24: 1584–93.
Zhang L, Chen J, Fu H . Suppression of apoptosis signal-regulating kinase 1 induced cell death by 14-3-3 protein. Proc Natl Acad Sci USA 1999; 96: 8511–5.
Chen J, Fujii K, Zhang L, Roberts T, Fu H . Raf-1 promotes cell survival by antagonizing apoptosis signal-regulating kinase 1 through a MEK-ERK independent mechanism. Proc Natl Acad Sci USA 2001; 14: 7783–8.
Goldman EH, Chen J, Fu H . Activation of apoptosis signal-regulating kinase 1 by reactive oxygen species through dephosphorylation at Ser967 and 14-3-3 dissociation. J Biol Chem 2004; 279: 10442–9.
Chun KH, Kosmeder JW, Sun S, Pezzuto JM, Lotan R, Hong WK . Effect of deguelin on the phosphatidylinositol 3-Kinase/Akt pathway and apoptosis in premalignant human bronchial epithelial cells. J Nat Cancer Inst 2003; 4: 292–302.
Chang HW, Aoki M, Fruman D, Auger KR, Bellacosa A, Tsichlis PN, et al. Transformation of chicken cells by the gene encoding the catalytic subunit of PI3K-Kinase. Science 1997; 276: 1848–50.
Klippel A, Escobedo MA, Wachowicz MS, Apell G, Brown TW, Giedlin MA, et al. Activation of phosphatidylinositol 3-kinase is sufficient for cell cycle entry and promotes cellular changes characteristic of oncogenic transformation. Mol Cell Biol 1998; 18: 5699–711.
Toker A, Cantley L . Signaling through the lipid products of phosphoinositide-3-OH kinase. Nature 1997; 387: 673–6.
Kobayashi M, Nagata S, Iwasaki T . Dedifferentiation of adenocarcinomas by activation of phosphatidylinositol 3-kinase. Proc Natl Acad Sci USA 1999; 96: 4874–9.
Luo J, Manning BD, Cantley LC . Targeting the PI3K-akt pathway in human cancer: Rationale and promise. Cancer Cell 2003; 4: 257–62.
Fu H, Subramanian HRS, Masters SC . 14-3-3 Proteins: structure, function, and regulation. Ann Rev Pharmacol Toxicol 2000; 40: 619–49.
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Project supported in part by Anhui Key Laboratory of Eco-engineering and Biotechnique Fund and National Institutes of Health Grants GM60033-03.
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Huang, B., Porter, G. Expression of proline-rich Akt-substrate PRAS40 in cell survival pathway and carcinogenesis. Acta Pharmacol Sin 26, 1253–1258 (2005). https://doi.org/10.1111/j.1745-7254.2005.00184.x
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DOI: https://doi.org/10.1111/j.1745-7254.2005.00184.x
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