Vascular endothelial growth factor-induced prostacyclin production is mediated by a protein kinase C (PKC)-dependent activation of extracellular signal-regulated protein kinases 1 and 2 involving PKC-delta and by mobilization of intracellular Ca2+
G. Gliki et al., Vascular endothelial growth factor-induced prostacyclin production is mediated by a protein kinase C (PKC)-dependent activation of extracellular signal-regulated protein kinases 1 and 2 involving PKC-delta and by mobilization of intracellular Ca2+, BIOCHEM J, 353, 2001, pp. 503-512
We reported previously that vascular endothelial growth factor (VEGF) stimu
lates prostacyclin (PGI(2)) production via activation of the extracellular
signal-regulated kinase (ERK) cascade. In this paper, we examined the role
of protein kinase C (PKC) in this pathway. VEGF-induced PGI(2) generation a
nd arachidonic acid release in human umbilical vein endothelial cells were
inhibited by the PKC inhibitors GF109203X and calphostin C. VEGF increased
PKC activity and immunoreactivity of the PKC delta, alpha and epsilon isofo
rms in particulate fractions of cells. PKC inhibitors blocked VEGF-induced
activation of ERK, MEK (mitogen-activated protein kinase kinase) and the cy
tosolic phospholipase A,, but had little effect on ERK activation induced b
y basic fibroblast growth factor. GF109203X, calphostin C and the PKC delta
-selective inhibitor, rottlerin, did not inhibit activation of the KDR rec
eptor for VEGF, Inhibition of Ca2+ fluxes using BAPTA/AM [1,12-bis-(o-amino
phenoxy)ethane-N,N,N',N'-tetra-acetic acid tetrakis(acetoxymethyl ester)] b
locked VEGF induced PGI, production but did not inhibit ERK activation. Nei
ther activation nor inhibition of the NO/cGMP pathway had any effect on VEG
F induction of ERK activity and PGI(2) synthesis. Wortmannin partially inhi
bited VEGF stimulation of PGI(2) production. but did not inhibit VEGF-induc
ed ERK activity. VEGF-induced ERK activation and PGI, production were block
ed by rottlerin, and VEGF increased association of PKC delta with Raf-l, th
e upstream activator of MEK. The PKC-selective inhibitor Go6976 did not inh
ibit ERK activation and had only a partial effect on PGI, production. These
findings indicate that activation of PKC plays a crucial role in VEGF sign
alling via the ERK cascade leading to PGI, synthesis and suggest that the P
KC delta isoform may be a key mediator of VEGF-induced activation of the ER
K pathway via increased association with Raf-l.