Celecoxib induces apoptosis by inhibiting 3-phosphoinositide-dependent protein kinase-1 activity in the human colon cancer HT-29 cell line.
Nonsteroidal anti-inflammatory drugs, which inhibit cyclooxygenase (COX) activity, are powerful antineoplastic agents that exert their antiproliferative and proapoptotic effects on cancer cells by COX-dependent and/or COX-independent pathways. Celecoxib, a COX-2-specific inhibitor, has been shown to reduce the number of adenomatous colorectal polyps in patients with familial adenomatous polyposis. Here, we show that celecoxib induces apoptosis in the colon cancer cell line HT-29 by inhibiting the 3-phosphoinositide-dependent kinase 1 (PDK1) activity. This effect was correlated with inhibition of the phosphorylation of the PDK1 downstream substrate Akt/protein kinase B (PKB) on two regulatory sites, Thr(308) and Ser(473). However, expression of a constitutive active form of Akt/PKB (myristoylated PKB) has a low protective effect toward celecoxib-induced cell death. In contrast, overexpression of constitutive active mutant of PDK1 (PDK1(A280V)) was as potent as the pancaspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, to impair celecoxib-induced apoptosis. By contrast, cells expressing a kinase-defective mutant of PDK1 (PDK1(K114G)) remained sensitive to celecoxib. Furthermore, in vitro measurement reveals that celecoxib was a potential inhibitor of PDK1 activity with an IC(50) = 3.5 microm. These data indicate that inhibition of PDK1 signaling is involved in the proapoptotic effect of celecoxib in HT-29 cells.
Arico
Sebastien
S
INSERM U504 Glycobiologie et Signalisation Cellulaire 16 avenue Paul-Vaillant-Couturier, Villejuif Cedex 94807, France.
Pattingre
Sophie
S
Bauvy
Chantal
C
Gane
Pierre
P
Barbat
Alain
A
Codogno
Patrice
P
Ogier-Denis
Eric
E
D064413:3-Phosphoinositide-Dependent Protein Kinases; D017209:Apoptosis / Q000187:drug effects*; D000068579:Celecoxib; D002470:Cell Survival / Q000187:drug effects*; D003110:Colonic Neoplasms; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007700:Kinetics; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D011720:Pyrazoles; D013449:Sulfonamides / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D016861:Cyclooxygenase Inhibitors; D011720:Pyrazoles; D013449:Sulfonamides; D010769:Phosphothreonine; D010768:Phosphoserine; D011494:Protein Kinases; D064413:3-Phosphoinositide-Dependent Protein Kinases; C578562:PDPK1 protein, human; D017346:Protein Serine-Threonine Kinases; D000068579:Celecoxib