Ey. Shin et al., Overexpressed alpha(3)beta(1) and constitutively activated extracellular signal-regulated kinase modulate the angiogenic properties of ECV304 cells, MOL CELLS, 9(2), 1999, pp. 138-145
ECV304, a spontaneously transformed cell line derived from the human umbili
cal vein endothelial cell (HUVEC) (Takahashi ct nl., 1990), has been develo
ped as an ill vitro angiogenesis model. In the present study, we further ch
aracterized the angiogenic properties of this cell line. Compared to HUVEC,
ECV304 cells showed distinct features including a higher activity of cellu
lar adhesion, slower but reproducible progression of angiogenesis on Matrig
el, and resistance to apoptosis. Thus, the expression of integrin and activ
ation of extracellular-signal regulated kinase 1/2 (Erk1/2), a downstream e
ffector of the integrin pathway, were examined. Flow cytometry revealed tha
t alpha(3)beta(1) integrin was markedly upregulated in ECV304 cells, while
alpha(v)beta(1) and alpha(5)beta(1) integrins were slightly downregulated.
Consistent with this, the binding activity to collagen type IV and laminin,
major extracellular matrices of Matrigel, was increased 1.4- and 1.9-fold
in ECV304 cells, respectively. This tight binding may retard the initial st
age of sprouting and migration in the angiogenesis of ECV304 cells. It has
been further demonstrated that Erk1/2 is constitutively active in ECV304 ce
lls, rendering them resistent to the inhibitory effect of PD98059 on prolif
eration. However, migration of both HUVEC and ECV304 cells was inhibited to
a similar extent by PD98059 in a dose-dependent manner. Up to 50 mu M of P
D98059, no significant changes in cell binding and tubulogenesis on Matrige
l was observed in ECV304 cells. In contrast, the tubulogenesis of HUVEC was
severely impaired by PD98059. Elevated Erk1/2 activity in ECV304 cells was
suppressed by dominant negative I-I-Ras, but not by cytochalasin D. These
results suggest that the overexpression of alpha(3)beta(1) integrin and the
constitutive activation of Erk1/2 play a key role in the alteration of the
angiogenic properties of ECV304 cells.