The pancreatic microenvironment has a defensive role against cancer but it can acquire tumor-promoting properties triggered by multiple mechanisms including alterations in the equilibrium between prot Show more
The pancreatic microenvironment has a defensive role against cancer but it can acquire tumor-promoting properties triggered by multiple mechanisms including alterations in the equilibrium between proteases and their inhibitors. The identification of proteolytic events, targets and pathways would set the basis for the design of new therapeutic approaches. Here we demonstrate that spheroids isolated from human and murine healthy pancreas and co-transplanted orthotopically with pancreatic ductal adenocarcinoma (PDAC) in mouse pancreas inhibited tumor growth. The effect was mediated by trypsin-generated fibronectin (FN) fragments released by pancreatic spheroids. Tumor inhibition was observed also in a model of acute pancreatitis associated with trypsin activation. Mass spectrometry proteomic analysis of fragments and mAb against different FN epitopes identified the FN type III domain as responsible for the activity. By inhibiting integrin α5β1, FAK and FGFR1 signaling, the fragments induced tumor cell detachment and reduced cell proliferation. Consistent with the mutual relationship between the two pathways, FGF2 restored both FGFR1 and FAK signaling and promoted PDAC cell adhesion and proliferation. FAK and FGFR inhibitors additively inhibited PDAC growth in vitro and in orthotopic in vivo models. This study identifies a novel role for pancreatic trypsin and fibronectin cleavage as a mechanism of protection against cancer by the pancreatic microenvironment. The finding of a FAK-FGFR cross-talk in PDAC support the combination of FAK and FGFR inhibitors for PDAC treatment to emulate the protective effect of the normal pancreas against cancer. Show less
Apoproteins (also known as apolipoproteins) have been studied extensively because of their role in lipid transport, association between specific genotypes and elevated serum lipid levels, and increase Show more
Apoproteins (also known as apolipoproteins) have been studied extensively because of their role in lipid transport, association between specific genotypes and elevated serum lipid levels, and increased risk of heart disease. There is considerable genetic variation in the geographic distributions of these markers, with a north-south cline of the APOE*4 allele observed in Europe by Lucotte et al. ([1997] Hum Biol 69:253-262). This study compares the frequencies of seven APO (APOA1 -75 bp, APOA1 +83 bp, APOB Ins/Del, APOB XbaI, APOC3 SstI, and APOE) and LPL loci in Mennonite populations from Kansas and Nebraska. In total, 277 individuals were sampled from Goessel, Meridian, Garden View, and Lone Tree in 2002-2004. In addition, DNA samples that were collected in 1981 from Henderson, Nebraska, were genotyped for the seven APO and LPL loci. Of the seven APO and LPL loci tested, only one locus, APOB XbaI, departed significantly from Hardy-Weinberg equilibrium, with an unexpected excess of observed heterozygotes. The frequencies of the several APO loci are unique among the Mennonites, separating them from other European populations. A bidimensional scaling representation of Reynold's co-ancestry distances based on allelic frequencies of the seven APO and LPL markers in five Mennonite congregations fails to represent schematically the known patterns of fission. It is unclear whether the observed patterns are due to selection operating on these loci or whether genetic drift, small populations sizes, or a lack of statistical power of these biallelic loci distort the observed genetic relationship among congregations. Show less