Blockade of the epidermal growth factor receptor signaling by a novel tyrosine kinase inhibitor leads to apoptosis of endothelial cells and therapy of human pancreatic carcinoma
Cj. Bruns et al., Blockade of the epidermal growth factor receptor signaling by a novel tyrosine kinase inhibitor leads to apoptosis of endothelial cells and therapy of human pancreatic carcinoma, CANCER RES, 60(11), 2000, pp. 2926-2935
We determined whether down-regulation of the epidermal growth factor-recept
or (EGF-R) signaling pathway by oral administration of a novel EGF-R tyrosi
ne kinase inhibitor (PKI166) alone or in combination with gemcitabine (admi
nistered i.p.) can inhibit growth and metastasis of human pancreatic carcin
oma cells implanted into the pancreas of nude mice. Therapy beginning 7 day
s after orthotopic injection of L3.6pl human pancreatic cancer cells reduce
d the volume of pancreatic tumors by 59% in mice treated with gemcitabine o
nly, by 45% in those treated with PKI166 only, and by 85% in those given bo
th drugs. The combination therapy also significantly inhibited lymph node a
nd liver metastasis, which led to a significant increase in overall surviva
l, EGF-R activation was significantly blocked by therapy with PKI166 and wa
s associated with significant reduction in tumor cell production of VEGF an
d IL-8, which in turn correlated with a significant decrease in microvessel
density and an increase in apoptotic endothelial cells. Collectively, our
results demonstrate that oral administration of an EGF-R tyrosine kinase in
hibitor decreased growth and metastasis of human pancreatic cancer growing
orthotopically in nude mice and increased survival. The therapeutic effects
were mediated in part by inhibition of tumor-induced angiogenesis attribut
able to a decrease in production of proangiogenic molecules by tumor cells
and increased apoptosis of tumor-associated endothelial cells.