erbB-2/neu transformed rat cholangiocytes recapitulate key cellular and molecular features of human bile duct cancer.
OBJECTIVE
Cholangiocarcinomas appear to arise from the malignant transformation of cholangiocytes lining the biliary tract. Because the development of an in vitro model of malignant transformation can provide a powerful new tool for establishing critical events governing the molecular pathogenesis of cholangiocarcinoma, we investigated the potential of achieving malignant transformation of cultured rat cholangiocytes in relation to aberrant overexpression of mutationally activated erbB-2/neu.


METHODS
Malignant neoplastic transformation was achieved after infection of the rat cholangiocyte cell line, designated BDE1, with the retrovirus Glu664-neu, containing the transforming rat erbB-2/neu oncogene.


RESULTS
Compared with untransformed control cells, malignant transformants carrying the activating erbB-2/neu mutation prominently overexpressed p185neu receptor protein, which was phosphorylated strongly at its major autophosphorylation site at tyrosine 1248. Moreover, erbB-2/neu transformation of BDE1 cells resulted in increased telomerase activity, up-regulation of cyclooxygenase-2 with overproduction of prostaglandin E(2), enhanced phosphorylation of mitogen-activated protein kinase and of serine/threonine kinase Akt/PKB, overexpression of vascular endothelial growth factor, and increased mucin 1 messenger RNA expression. Only erbB-2/neu transformants were tumorigenic when transplanted into isogeneic rats, yielding a 100% incidence of tumors closely resembling human desmoplastic ductal cholangiocarcinomas in their morphology. Malignant cholangiocytes in the tumors were strongly immunoreactive for biliary cytokeratin 19, p185neu, and cyclooxygenase-2.


CONCLUSIONS
This unique malignant transformation model recapitulates key molecular features of the human disease and appears to be well suited for testing novel molecular therapeutic strategies against cholangiocarcinoma.
Lai
Guan-Hua
GH
Division of Cellular and Molecular Pathogenesis, Department of Pathology, Virginia Commonwealth University School of Medicine, Medical College of Virginia Campus, Richmond, Virginia 23298-0297, USA.
Zhang
Zichen
Z
Shen
Xue-Ning
XN
Ward
Deanna J
DJ
Dewitt
Jennifer L
JL
Holt
Shawn E
SE
Rozich
Rebecca A
RA
Hixson
Douglas C
DC
Sirica
Alphonse E
AE
D000818:Animals; D001650:Bile Duct Neoplasms / Q000378:metabolism / Q000473:pathology; D001652:Bile Ducts / Q000166:cytology*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006801:Humans; D008099:Liver / Q000473:pathology; D051381:Rats; D011916:Rats, Inbred F344; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D019098:Telomerase / Q000378:metabolism
D018719:Erb-b2 Receptor Tyrosine Kinases; D019098:Telomerase