CholecystokininB receptor from human Jurkat lymphoblastic T cells is involved in activator protein-1-responsive gene activation.
The aim of this study was to analyze the role of cholecystokinin (CCK(B)) receptor in human lymphoblastic Jurkat T cells. We investigated the trophic effect resulting from activation of such a receptor by using the reporter gene strategy. For this purpose, we transiently transfected Jurkat T cells with the reporter plasmid p[(TRE)3-tk-Luc] and found that CCK-8 was able to dose-dependently induce luciferase expression related to activator protein-1 (AP-1) activation with a maximal response identical to that obtained with compounds known to activate AP-1 complex (quantitatively, the same level of induction was obtained with 1 nM 12-O-tetradecanoylphorbol-13-acetate, 100 microM diacylglycerol, or 4 nM epidermal growth factor). The involvement of the CCK(B) receptor in such a stimulation was demonstrated by the inhibiting effect of the selective CCK(B) receptor antagonist PD-135,158. This effect was confirmed in COS-7 cells transfected with the cDNA of CCK(B) receptor cloned from Jurkat T cells. To better understand the AP-1-dependent luciferase expression in Jurkat T cells, we tested two specific inhibitors of serine/threonine phosphatases-1 and -2A: okadaic acid and calyculin A. These compounds strongly increased the phorbol-12-myristate-13-acetate response, whereas we have not observed a contribution of phosphatase inhibitors on a CCK-8-induced luciferase activity. To confirm that CCK(B) receptors are involved in AP-1 response, we investigated the CCK-8 effect on interleukin-2 expression, a natural endogenous gene regulated by several factors, including AP-1. In Jurkat T cells activated by phorbol-12-myristate-13-acetate and phytohemagglutinin, CCK-8 induced IL-2 expression. This induction was abolished by PD-135,158. Our results indicate that CCK-8 exerts a trophic effect in Jurkat T cells through stimulation of CCK(B) receptors by modulation of expression of AP-1-regulated genes.
Oiry
C
C
Laboratoire des Amino Acides, Peptides et Protéines, ESA.CNRS 5075, Universités de Montpellier I et II Faculté de Pharmacie, France.
Gagne
D
D
Cottin
E
E
Bernad
N
N
Galleyrand
J C
JC
Bergé
G
G
Lignon
M F
MF
Eldin
P
P
Le Cunff
M
M
Léger
J
J
Clerc
P
P
Fourmy
D
D
Martinez
J
J
D000818:Animals; D001667:Binding, Competitive; D019556:COS Cells; D002455:Cell Division; D002460:Cell Line; D003001:Cloning, Molecular; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics; D019169:Jurkat Cells; D008024:Ligands; D011949:Receptors, Cholecystokinin / Q000502:physiology*; D012844:Sincalide / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000502:physiology*; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation
D007376:Interleukin-2; D008024:Ligands; D011949:Receptors, Cholecystokinin; D018808:Transcription Factor AP-1; D012844:Sincalide