Estrogens stimulate the proliferation of human cholangiocarcinoma by inducing the expression and secretion of vascular endothelial growth factor.
BACKGROUND
Estrogens may induce the proliferation of neoplastic cells by activating neo-angiogenesis.


OBJECTIVE
To evaluate the effect of estrogens on the expression of vascular endothelial growth factor (VEGF) and related receptors (VEGF-R) in human cholangiocarcinoma and the role played by VEGF in mediating the proliferative effects of estrogens.


METHODS
Seven biopsies of intra-hepatic cholangiocarcinoma and the HuH-28 cell lines were investigated. Cell proliferation was measured by both PCNA Western blot and MTS proliferation assay.


RESULTS
By immunohistochemistry, biopsies of human cholangiocarcinoma stained positively for VEGF-A and VEGF-C and related receptors. HuH-28 cells expressed VEGF-A, -C, and VEGFR-1, -2, -3 and, their protein level was enhanced by 17beta-estradiol in association with the stimulation of cell proliferation. 17beta-Estradiol-stimulated proliferation of HuH-28 cells was blocked by 70% by VEGF-TRAP, a receptor-based VEGF inhibitor. 17beta-Estradiol induced the secretion of VEGF in the supernatant of HuH-28 cells. The stimulatory effect of 17beta-estradiol on the protein expression of VEGF-A, VEGF-C and VEGFR-1, -2, -3 was blocked by antagonists of ER (Ici182,780) or insulin-like growth factor 1-receptor (alphaIR3).


CONCLUSIONS
With the limitations of experiments performed in a cell line, our study indicates that VEGF plays a major role in mediating the proliferative effects of estrogens on human cholangiocarcinoma.
Mancino
A
A
Department of Clinical Medicine, Division of Gastroenterology, University of Rome, La Sapienza, Rome, Italy.
Mancino
M G
MG
Glaser
S S
SS
Alpini
G
G
Bolognese
A
A
Izzo
L
L
Francis
H
H
Onori
P
P
Franchitto
A
A
Ginanni-Corradini
S
S
Gaudio
E
E
Alvaro
D
D
D000368:Aged; D001650:Bile Duct Neoplasms / Q000473:pathology / Q000503:physiopathology*; D001653:Bile Ducts, Intrahepatic / Q000187:drug effects / Q000503:physiopathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018281:Cholangiocarcinoma / Q000473:pathology / Q000503:physiopathology*; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D040262:Receptors, Vascular Endothelial Growth Factor / Q000187:drug effects / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000187:drug effects* / Q000378:metabolism
D004967:Estrogens; D042461:Vascular Endothelial Growth Factor A; D004958:Estradiol; D040262:Receptors, Vascular Endothelial Growth Factor