Gemcitabine synergistically enhances the effect of adenovirus gene therapy through activation of the CMV promoter in pancreatic cancer cells.

Adenovirus-mediated gene therapy shows remarkable promise as a new strategy for advanced pancreatic cancer, but satisfactory clinical results have not yet been obtained. To improve this gene therapy, we investigated the effects of gemcitabine (GEM) on transgene expression by adenoviral vectors and their biological effects. We used Ad-lacZ and adenoviral vector-expressing NK4 (Ad-NK4) as representative adenoviral vectors. These vectors express beta-galactosidase (beta-gal) and NK4 (which inhibits the invasion of cancer cells), respectively, under the control of the CMV promoter. Cells were infected with the individual adenoviruses and then treated with GEM. GEM increased beta-gal mRNA expression and beta-gal activity, and increased NK4 expression in both culture media and within infected cells, in dose-dependent manners. The increased expression of NK4 delivered by Ad-NK4 had biological effects by inhibiting the invasion of cancer cells. GEM also enhanced NK4 expression in SUIT-2 cells transfected with an NK4-expressing plasmid, suggesting that GEM enhanced CMV promoter activity. In in vivo experiments, NK4 expression within subcutaneously implanted tumors was increased in GEM-treated mice compared with control mice. These results suggest that adenovirus-mediated gene therapy with GEM may be a promising approach for treating pancreatic cancer, and that this combination therapy may decrease the risks of side effects.

Over-expression of S100A2 in pancreatic cancer correlates with progression and poor prognosis.

Controversy exists regarding the clinical significance of S100A2 in the progression of tumours. In pancreatic cancer, little is known about the role of S100A2. The aim of this study was to clarify the clinical significance of S100A2 expression in pancreatic carcinogenesis. We microdissected invasive ductal carcinoma (IDC) cells from 22 lesions, pancreatic intraepithelial neoplasia (PanIN) cells from five lesions, intraductal papillary mucinous neoplasm (IPMN) cells from 38 lesions, pancreatitis-affected epithelial (PAE) cells from 16 lesions, and normal ductal cells from 18 normal pancreatic tissues. S100A2 expression in 14 pancreatic cancer cell lines, microdissected cells and formalin-fixed paraffin-embedded (FFPE) samples was examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Microdissection analyses revealed that IDC cells expressed higher levels of S100A2 than did IPMN, PAE or normal cells (all comparisons, p < 0.007). Cell lines from metastatic sites expressed higher levels of S100A2 than those from primary sites. PanIN cells expressed higher levels of S100A2 than normal cells (p = 0.018). IDC cells associated with poorly differentiated adenocarcinoma expressed higher levels of S100A2 than did IDC cells without poorly differentiated adenocarcinoma (p = 0.006). Analyses of FFPE samples revealed that levels of S100A2 were higher in samples from patients who survived < 1000 days after surgery than in those from patients who survived > 1000 days (p = 0.043). Immunohistochemical analysis was consistent with qRT-PCR. S100A2 may be a marker of tumour progression or prognosis in pancreatic carcinogenesis and pancreatic cancer.

Sonic hedgehog is an early developmental marker of intraductal papillary mucinous neoplasms: clinical implications of mRNA levels in pancreatic juice.

Intraductal papillary mucinous neoplasms (IPMNs) are common cystic tumours of the pancreas. Sonic hedgehog (SHH) is involved in gastric epithelial differentiation and pancreatic carcinogenesis. However, a comprehensive analysis of SHH expression in IPMN has not yet been performed. In the present study, one-step quantitative real-time reverse transcription-polymerase chain reaction with gene-specific priming was used to examine mRNA levels in various types of clinical samples. SHH expression in IPMN was measured and the possible association of gastric epithelial differentiation with development of IPMN was evaluated. In bulk tissue analyses (IPMNs, 11 pancreatic cancer, and 20 normal pancreatic tissues), IPMN expressed significantly higher levels of SHH than did normal pancreas (IPMN versus normal pancreas, p = 0.0025; pancreatic cancer versus normal pancreas, p = 0.0132), but SHH expression did not differ between IPMN and pancreatic cancer (p = 0.3409). In microdissection analyses (infiltrating ductal carcinoma cells from 20 sections, IPMN cells from 20 sections, pancreatitis-affected epithelial cells from 11 sections, and normal epithelial cells from 12 sections), IPMN cells expressed significantly higher levels of SHH than did cancer cells, normal cells, or pancreatitis-affected ductal cells (all comparisons, p < 0.008). Pancreatic juice analyses (20 samples from pancreatic cancers, 31 samples from IPMNs, and 27 samples from chronic pancreatitis) revealed that SHH expression differed significantly between IPMN juice and pancreatitis juice (p < 0.0001), and between cancer juice and pancreatitis juice (p = 0.0125). Receiver operating characteristic curve analyses revealed that SHH measurement in pancreatic juice was useful for discriminating IPMN from chronic pancreatitis (area under the curve = 0.915; 95% confidence interval: 0.796-0.976). The data suggest that overexpression of SHH is an early event in the development of IPMN and that SHH measurement in pancreatic juice may provide some advantages for the treatment or follow-up of a subset of patients with IPMN or chronic pancreatitis.