Souichirou Yamasaki

Expressions of Angiogenic Factors in Pancreatic Ductal Carcinoma : A Correlative Study with Clinicopathologic Parameters and Patient Survival

Introduction It has been reported that angiogenic factors play an important role in proliferation and metastasis in various cancers. Aim To investigate the expression of angiogenic factors and microvessel density (MVD) in pancreatic ductal carcinoma and to examine the correlations among expression of angiogenic factors, clinicopathologic parameters, and clinical prognosis. Methodology Paraffin-embedded specimens from 55 patients with pancreatic ductal carcinoma were immunostained for vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), platelet-derived endothelial cell growth factor (PD-ECGF), and CD34. The correlations among the expression of individual angiogenic factors and MVD, the clinicopathologic features, and the clinical prognoses were analyzed statistically. Results Immunostaining demonstrated that 70.8% of pancreatic ductal carcinomas were positive for VEGF, 60.9% for FGF-2, and 57.2% for PD-ECGF. A significant correlation was observed between VEGF expression and MVD (p < 0.05) but not between FGF-2 or PD-ECGF and MVD. Although the expression of each angiogenic factor had no correlation with clinicopathologic features, the patients with tumors that showed high expression of VEGF and FGF-2 had significantly shorter survival times than those with low or no such expression (p < 0.05). Conclusions These observations suggest that the expression of VEGF closely correlates with MVD and with a poor prognosis in pancreatic ductal carcinoma.

Preoperative diagnosis of intraductal papillary‐mucinous tumors of the pancreas with attention to telomerase activity

It has been reported that, in patients with intraductal papillary‐mucinous tumor (IPMT) of the pancreas, it is difficult to distinguish adenoma from carcinoma preoperatively. Recently, it has also been reported that telomerase activity was detected in many patients with carcinoma. In this report, the authors used the method of telomerase repeat amplification protocol (TRAP) assay on pancreatic juice retrieved by endoscopic retrograde pancreatic juice aspiration (ERP aspiration).

Screening of genes specifically activated in the pancreatic juice ductal cells from the patients with pancreatic ductal carcinoma.

Pancreatic ductal carcinoma (PDC) is one of the most intractable human malignancies. Surgical resection of PDC at curable stages is hampered by a lack of sensitive and reliable detection methods. Given that DNA microarray analysis allows the expression of thousands of genes to be monitored simultaneously, it offers a potentially suitable approach to the identification of molecular markers for the clinical diagnosis of PDC. However, a simple comparison between the transcriptomes of normal and cancerous pancreatic tissue is likely to yield misleading pseudopositive data that reflect mainly the different cellular compositions of the specimens. Indeed, a microarray comparison of normal and cancerous tissue identified the INSULIN gene as one of the genes whose expression was most specific to normal tissue. To eliminate such a “population‐shift” effect, the pancreatic ductal epithelial cells were purified by MUC1‐based affinity chromatography from pancreatic juice isolated from both healthy individuals and PDC patients. Analysis of these background‐matched samples with DNA microarrays representing 3456 human genes resulted in the identification of candidate genes for PDC‐specific markers, including those for AC133 and carcinoembryonic antigen‐related cell adhesion molecule 7 (CEACAM7). Specific expression of these genes in the ductal cells of the patients with PDC was confirmed by quantitative real‐time polymerase chain reaction analysis. Microarray analysis with purified pancreatic ductal cells has thus provided a basis for the development of a sensitive method for the detection of PDC that relies on pancreatic juice, which is routinely obtained in the clinical setting. (Cancer Sci 2003; 94: 263–270)

Irsogladine Malate Up-regulates Gap Junctional Intercellular Communication Between Pancreatic Cancer Cells Via PKA Pathway

Introduction Gap junctions (GJs) are intercellular channels that aid communication between coupling cells and may play a critical role in cell differentiation and growth. Connexins (Cxs) are structural proteins of GJs. Though several reports have demonstrated that Cx expression decreases in various malignant tumors, a pancreatic cancer cell line, PANC-1, was reported to express Cx43 mRNA. It is known that irsogladine malate (IM) can up-regulate gap junctional intercellular communication (GJIC). We examined the effects of IM on GJ between pancreatic cancer cells (PC cells) and the mechanism of GJ up-regulation. Methodology GJIC between PC cells (PANC-1) was evaluated by dye transfer methods. The expression of Cx43 was estimated by Western blot analysis with immunoprecipitation sample and immunohistochemical analysis. Intracellular cAMP level was estimated by enzyme-linked immunoassay. Results IM increased cell coupling in a dose-dependent manner (0M-10−4M). Western blot analysis of Cx43 revealed that PANC-1 cells expressed Cx43 protein. Treatment with IM was found to move localization of Cx43 immunoreactive spots from the cytoplasm to boundary lesions with neighboring cells, but no major change was seen in the phosphorylation state of Cx43. Intracellular cAMP level was increased by IM. The PKA inhibitor H-89 and adenylyl cyclase inhibitor SQ22536 inhibited the effects of IM. Conclusion These results suggest that IM up-regulates GJIC between PC cells via regulation of the PKA pathway. It also suggests a useful adjuvant of IM to pancreatic cancer therapy.