Syndecan‐1 belongs to the syndecan family of cell surface transmembrane heparan‐sulfate proteoglycans, which participate in cell proliferation, cell migration and cell‐matrix interactions. Decreased expression of syndecan‐1 has been observed in some gastrointestinal malignancies, and it is thought that high levels of syndecan‐1 correlate with the maintenance of epithelial morphology and inhibition of invasiveness. In our study, we characterized the expression of syndecan‐1 in normal, chronic pancreatitis and primary and metastatic human pancreatic cancer tissues, in cultured pancreatic cancer cell lines and in esophageal, gastric, colon, and liver cancers. Pancreatic cancer cell lines expressed syndecan‐1 mRNA and protein at variable levels. In addition, these cells also released syndecan‐1 into the culture medium. Pancreatic cancer tissues markedly over‐expressed syndecan‐1 mRNA in comparison with both chronic pancreatitis (2.4‐fold increase, p < 0.01) and normal pancreatic samples (10.6‐fold increase, p < 0.01). There was no difference in syndecan‐1 mRNA expression between early and advanced tumors. By in situ hybridization and immunohistochemistry, syndecan‐1 expression was evident at relatively low levels in the ductal cells and less frequently in acinar cells of the normal pancreas. In chronic pancreatitis, syndecan‐1 was present at low to moderate levels in areas with atrophic acinar cells and ductular complexes. In contrast, in pancreatic cancer tissues, syndecan‐1 was present at moderate to high levels in the majority of the cancer cells within the tumor mass and also in metastatic lesions of pancreatic tumors. Syndecan‐1 mRNA levels in other gastrointestinal malignancies (esophageal, gastric, colon and liver cancers) were not significantly different from the levels observed in the corresponding normal samples. Together, our findings suggest that syndecan‐1 expression by pancreatic cancer cells may be of importance in the pathobiology of this disorder and that its role in pancreatic cancer seems to be different from that in other gastrointestinal malignancies. Int. J. Cancer 88:12–20, 2000. © 2000 Wiley‐Liss, Inc.

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Vascular endothelial growth factor (VEGF) is a potent angiogenic stimulator that acts by binding to high-affinity transmembrane receptors. Although both VEGF and its receptors are overexpressed in human pancreatic ductal adenocarcinoma (PDAC), this malignancy is not generally considered to be highly vascular. It is not known, therefore, whether the abundance of VEGF in PDAC is biologically relevant. To address this issue, we measured the angiogenic effects of pancreatic cancer cell-derived VEGF in an in vitro endothelial cell proliferation assay and characterized the consequences of suppressing VEGF expression on pancreatic tumor growth in an athymic nude mouse model. We found that human pancreatic cancer cell lines secrete large quantities of biologically active VEGF into conditioned medium (CM). Stable transfection of an anti-sense VEGF 189 (AS-VEGF 189 ) expression construct into PANC-1 pancreatic cancer cells resulted in decreased VEGF expression and secretion, a decreased capacity of the resultant CM to enhance endothelial cell proliferation and a significant attenuation of tumor cell proliferation in vitro. Furthermore, when injected into athymic nude mice, AS-VEGF 189 -expressing cells exhibited an 80% decrease in tumor growth compared with control cells. These results support the hypothesis that VEGF promotes pancreatic cancer growth in vivo and suggest that anti-VEGF therapy may be useful in the treatment of this disease.

Vascular endothelial growth factor C (VEGF-C) is a lymphangiogenic polypeptide that has been implicated in cancer growth. In this study, we characterized VEGF-C expression in cultured human pancreatic cancer cell lines and determined whether the presence of VEGF-C in human pancreatic cancers is associated with clinicopathologic characteristics. VEGF-C mRNA transcripts were present in all five tested cell lines (Capan-1, MIA-PaCa-2, PANC-1, COLO-357, and T3M4). Immunoblotting with a highly specific anti-VEGF-C antibody revealed the presence of VEGF-C protein in all the cell lines. Northern blot analysis of total RNA revealed an approximately 2.2-fold increase in VEGF-C mRNA transcript in the cancer samples compared with the normal pancreas. Immunohistochemical analysis confirmed the expression of VEGF-C and its receptor flt-4 in the cancer cells within the tumor mass. Immunohistochemical analysis of 51 pancreatic cancer tissues revealed the presence of strong VEGF-C immunoreactivity in the cancer cells in 80.4% of the cancer tissues. The presence of VEGF-C in these cells was associated with increased lymphatic vessels invasion and lymph node metastasis, but not with decreased patient survival. These findings indicate that VEGF-C and its receptor are commonly overexpressed in human pancreatic cancers and that this factor may contribute to the lymphangiogenic process and metastasis in this disorder.