Pancreatic carcinoma cells induce fibrosis by stimulating proliferation and matrix synthesis of stellate cells.
OBJECTIVE
Tumor desmoplasia is one of the representative histopathologic findings in ductal pancreatic adenocarcinoma. The aims of this study were to examine the cellular and molecular mechanisms of fibrogenesis associated with pancreatic adenocarcinomas.


METHODS
Immunostainings were performed with human pancreatic adenocarcinomas (n = 27) and tumors induced in nude mice (n = 36) by subcutaneously injecting MiaPaCa2, Panc1, and SW850 with and without pancreatic stellate cells. Matrix-producing cells were isolated from pancreatic adenocarcinomas and compared with pancreatic stellate cells isolated from tissue of chronic pancreatitis. Paracrine stimulation of pancreatic stellate cells by carcinoma cells was studied regarding matrix synthesis (collagen and c-fibronectin on protein and messenger RNA level) and cell proliferation (bromodeoxyuridine incorporation).


RESULTS
High numbers of desmin and alpha-smooth muscle actin-positive cells were detected in 26 of 27 pancreatic adenocarcinomas. Intense fibronectin and collagen stainings were associated with these cells. By using cytofilament stainings, gene expression profiling, and morphological examinations, the matrix-producing cells obtained by the outgrowth method from pancreatic adenocarcinomas were identified as pancreatic stellate cells. Supernatants of MiaPaCa2, Panc1, and SW850 cells stimulated proliferation and collagen type I and c-fibronectin synthesis of cultured pancreatic stellate cells. Preincubation of the carcinoma cell supernatants with neutralizing antibodies against fibroblast growth factor 2, transforming growth factor beta 1, and platelet-derived growth factor significantly reduced the stimulatory effects. Subcutaneous injection of carcinoma cells and pancreatic stellate cells induced fast-growing subcutaneous fibrotic tumors in nude mice. Morphometric analysis of carcinoma cells (cytokeratin stainings) showed a high density of carcinoma cells in these tumors.


CONCLUSIONS
Pancreatic stellate cells strongly support tumor growth in the nude mouse model. The increased deposition of connective tissue in pancreatic carcinoma is the result of a paracrine stimulation of pancreatic stellate cells by carcinoma cells.
Bachem
Max G
MG
Department of Clinical Chemistry, University of Ulm, D-89070 Ulm, Germany. max.bachem@medizin.uni-ulm.de
Schünemann
Marion
M
Ramadani
Marco
M
Siech
Marco
M
Beger
Hans
H
Buck
Andreas
A
Zhou
Shaoxia
S
Schmid-Kotsas
Alexandra
A
Adler
Guido
G
D000199:Actins / Q000378:metabolism; D000818:Animals; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D017690:Cell Transplantation; D002908:Chronic Disease; D003094:Collagen / Q000378:metabolism; D003893:Desmin / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism*; D005355:Fibrosis; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology; D010179:Pancreas / Q000378:metabolism* / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D010195:Pancreatitis / Q000378:metabolism / Q000473:pathology
D000199:Actins; D003893:Desmin; D003094:Collagen