Pancreatic carcinoma cells express neuropilins and vascular endothelial growth factor, but not vascular endothelial growth factor receptors.
BACKGROUND
Neuropilins (NRPs) are characterized as coreceptors of vascular endothelial growth factor (VEGF). In the current study, the authors assessed the expression of NRPs, VEGF, and vascular endothelial growth factor receptors (VEGFRs), as well as VEGF-induced cell proliferation, in pancreatic carcinoma cell lines and tissue specimens.


METHODS
Human pancreatic carcinoma cell lines (Panc-1 and MIA PaCa-2), normal human pancreatic ductal epithelial cells (HPDE), and human umbilical vein endothelial cells (HUVECs) were cultured. Human pancreatic adenocarcinoma tissue specimens were also studied. Expression levels of NRPs, VEGFRs, and VEGF were determined by real-time polymerase chain reaction analysis and immunostaining. Cell proliferation was examined using a [3H]thymidine incorporation assay.


RESULTS
Both NRP-1 and NRP-2 were expressed in Panc-1 cells, HPDE cells, and HUVECs but were expressed minimally in MIA PaCa-2 cells. Panc-1 expressed 30 times more NRP-1 mRNA than NRP-2 mRNA. NRP-1 levels in Panc-1 cells were 5.3 times higher than in HPDE cells but were similar to NRP-1 levels in HUVECs. NRP-2 levels in Panc-1 cells were similar to NRP-2 levels in HPDE cells but lower than NRP-2 levels in HUVECs. Expression of all three VEGFRs was observed only in HUVECs. However, VEGF mRNA was detected in all cell types except for HUVECs. NRP-1 immunoreactivity levels were much higher than NRP-2 immunoreactivity levels in Panc-1 and human pancreatic adenocarcinoma tissue specimens, whereas VEGFRs were not detected in either of these two settings. In response to VEGF165, [3H]thymidine incorporation in Panc-1 cells increased significantly (by 61%; P < 0.01). A monoclonal antibody against human NRP-1 significantly blocked VEGF-induced cell proliferation in Panc-1 cells.


CONCLUSIONS
The pancreatic carcinoma cell line Panc-1 and adenocarcinoma tissue specimens expressed high levels of NRP-1 and VEGF, but not VEGFRs, and exogenous VEGF significantly increased NRP-1-mediated, but not VEGFR-mediated, Panc-1 cell proliferation. These data suggested that NRP-1 may be involved in the pathogenesis of pancreatic carcinoma.
Li
Min
M
Molecular Surgeon Research Center, Michael E. DeBakey Department of Surgery, Baylor College of Medicine/Methodist Hospital, Houston, Texas 77030, USA.
Yang
Hui
H
Chai
Hong
H
Fisher
William E
WE
Wang
Xiaoping
X
Brunicardi
F Charles
FC
Yao
Qizhi
Q
Chen
Changyi
C
D000230:Adenocarcinoma / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D017931:DNA Primers; D042783:Endothelial Cells / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D039921:Neuropilins / Q000096:biosynthesis*; D010183:Pancreatic Ducts / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D040262:Receptors, Vascular Endothelial Growth Factor / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014470:Umbilical Cord / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*
D017931:DNA Primers; D039921:Neuropilins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D040262:Receptors, Vascular Endothelial Growth Factor