The reg4 gene, amplified in the early stages of pancreatic cancer development, is a promising therapeutic target.

BACKGROUND: The aim of our work was to identify the genes specifically altered in pancreatic adenocarcinoma and especially those that are altered early in cancer development. METHODOLOGY/PRINCIPAL FINDINGS: Gene copy number was systematically assessed with an ultra-high resolution CGH oligonucleotide microarray in DNA from samples of pancreatic cancer. Several new cancer-associated variations were observed. In this work we focused on one of them, involving the reg4 gene. Gene copy number gain of the reg4 gene was confirmed by qPCR in 14 cancer samples. It was also found with increased copy number in most PanIN3 samples. The relationship betweena gain in reg4 gene copy number and cancer development was investigated on the human pancreatic cancer cell line Mia-PaCa2 xenografted under the skin of nude mice. When cells were transfected with a vector allowing reg4 expression, they generated tumors almost twice larger in size. In addition, these tumors were more resistant to gemcitabine treatment than control tumors. Interestingly, weekly intraperitoneal administration of a monoclonal antibody to reg4 halved the size of tumors generated by Mia-PaCa2 cells, suggesting that the antibody interfered with a paracrine/autocrine mechanism involving reg4 and stimulating cancer progression. The addition of gemcitabine resulted in further reduction, tumors becoming 5 times smaller than control. Exposure to reg4 antibody resulted in a significant decrease in intra-tumor levels of pAkt, Bcl-xL, Bcl-2, survivin and cyclin D1. CONCLUSIONS/SIGNIFICANCE: It was concluded that adjuvant therapies targeting reg4 could improve the standard treatment of pancreatic cancer with gemcitabine.

Identification of genomic alterations associated with the aggressiveness of pancreatic cancer using an ultra-high-resolution CGH array.

BACKGROUND: Genomic alterations present in pancreatic adenocarcinoma have been described only partially. In addition, the relations between these alterations and the aggressiveness of the phenotype remain unknown. METHODS: Genomic DNA and total RNA from 5 pancreatic cell lines, of which 2 have an aggressive phenotype and are gemcitabine-resistant (Mia-Paca2 and Panc-1), and 3 less aggressive and gemcitabine-sensitive (Capan-1, Capan-2 and BxPC3), have been purified. DNA abnormalities have been analyzed using an ultra-high-resolution CGH array and mRNA expression was studied with an Affymetrix GeneChip expression array. RESULTS: We identified 573 amplified and 30 deleted genes common to all 5 cell lines. Some of them have already been described, whereas other genes, implicated in signal transduction, apoptosis, cell cycle or cell migration, are described for the first time as being related to this cancer. Comparison of genomic abnormalities between the 2 most aggressive and the 3 less aggressive cell lines led to the identification of 368 genes specifically amplified in the aggressive cell lines. However, no specific gene deletion seems to be associated with the aggressive phenotype. CONCLUSION: Using a high-resolution approach, we could precisely describe the genomic alterations associated with pancreatic adenocarcinoma and determine those associated with an aggressive phenotype.

Experimental acute pancreatitis in PAP/HIP knock-out mice.

BACKGROUND AND AIMS: PAP/HIP was first reported as an additional pancreatic secretory protein expressed during the acute phase of pancreatitis. It was shown in vitro to be anti-apoptotic and anti-inflammatory. This study aims to look at whether PAP/HIP plays the same role in vivo. METHODS: A model of caerulein-induced pancreatitis was used to compare the outcome of pancreatitis in PAP/HIP(-/-) and wild-type mice. RESULTS: PAP/HIP(-/-) mice showed the normal phenotype at birth and normal postnatal development. Caerulein-induced pancreatic necrosis was, however, less severe in PAP/HIP(-/-) mice than in wild-type mice, as judged by lower amylasemia and lipasemia levels and smaller areas of necrosis. On the contrary, pancreas from PAP/HIP(-/-) mice was more sensitive to apoptosis, in agreement with the anti-apoptotic effect of PAP/HIP in vitro. Surprisingly, pancreatic inflammation was more extensive in PAP/HIP(-/-) mice, as judged from histological parameters, increased myeloperoxidase activity and increased pro-inflammatory cytokine expression. This result, in apparent contradiction with the limited necrosis observed in these mice, is, however, in agreement with the anti-inflammatory function previously reported in vitro for PAP/HIP. This is supported by the observation that activation of the STAT3/SOCS3 pathway was strongly decreased in the pancreas of PAP/HIP(-/-) mice and by the reversion of the apoptotic and inflammatory phenotypes upon administration of recombinant PAP/HIP to PAP/HIP(-/-) mice. CONCLUSION: The anti-apoptotic and anti-inflammatory functions described in vitro for PAP/HIP have physiological relevance in the pancreas in vivo during caerulein-induced pancreatitis.

Vanin-1 licenses inflammatory mediator production by gut epithelial cells and controls colitis by antagonizing peroxisome proliferator-activated receptor gamma activity.

Colitis involves immune cell-mediated tissue injuries, but the contribution of epithelial cells remains largely unclear. Vanin-1 is an epithelial ectoenzyme with a pantetheinase activity that provides cysteamine/cystamine to tissue. Using the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-colitis model we show here that Vanin-1 deficiency protects from colitis. This protection is reversible by administration of cystamine or bisphenol A diglycidyl ether, a peroxisome proliferator-activated receptor (PPAR)gamma antagonist. We further demonstrate that Vanin-1, by antagonizing PPARgamma, licenses the production of inflammatory mediators by intestinal epithelial cells. We propose that Vanin-1 is an epithelial sensor of stress that exerts a dominant control over innate immune responses in tissue. Thus, the Vanin-1/pantetheinase activity might be a new target for therapeutic intervention in inflammatory bowel disease.