Fluorescent dye labeling is a common strategy to analyze the fate of administered nanoparticles in living organisms. However, to which extent the labeling processes can alter the original nanoparticle biodistribution has been so far neglected. In this work, two widely used fluorescent dye molecules, namely, ATTO488 (ATTO) and Sulfo-Cy5 (S-Cy5), have been covalently attached to a well-characterized CXCR4-targeted self-assembling protein nanoparticle (known as T22-GFP-H6). The biodistribution of labeled T22-GFP-H6-ATTO and T22-GFP-H6-S-Cy5 nanoparticles has been then compared to that of the non-labeled nanoparticle in different CXCR4+ tumor mouse models. We observed that while parental T22-GFP-H6 nanoparticles accumulated mostly and specifically in CXCR4+ tumor cells, labeled T22-GFP-H6-ATTO and T22-GFP-H6-S-Cy5 nanoparticles showed a dramatic change in the biodistribution pattern, accumulating in non-target organs such as liver or kidney while reducing tumor targeting capacity. Therefore, the use of such labeling molecules should be avoided in target and non-target tissue uptake studies during the design and development of targeted nanoscale drug delivery systems, since their effect over the fate of the nanomaterial can lead to considerable miss-interpretations of the actual nanoparticle biodistribution.

The aim of the present study was to determine the effects of a cafeteria diet on the function and apoptosis of the pancreas, and the activity and expression of the insulin-degrading enzyme (IDE). Female Wistar rats were fed either with a cafeteria diet or a control diet for 17 weeks, and blood and tissues were then collected for analysis. The cafeteria diet-treated rats had higher plasma insulin and C-peptide levels (P < 0·05), showing increased insulin secretion by the pancreas. Insulin protein and gene expression levels were higher in the pancreas of obese rats, as was its transcriptional controller, pancreatic duodenal homeobox 1 (P < 0·05). Feeding a cafeteria diet down-regulated the gene expression of the anti-apoptotic marker B-cell/lymphoma 2 (BCL2), and up-regulated the protein levels of BCL2-associated X protein, a pro-apoptotic marker (P < 0·05). The cafeteria diet caused lipid accumulation in the pancreas and modified the expression of key genes that control lipid metabolism. To assay whether insulin clearance was also modified, we checked the activity of the IDE, one of the enzymes responsible for insulin clearance. We found increased liver IDE activity (P < 0·05) in the cafeteria diet-fed animals, which could, in part, be due to an up-regulation of its gene expression. Conversely, IDE gene expression was unmodified in the kidney and adipose tissue; although when the adipose tissue weight was considered, the insulin clearance potential was higher in the cafeteria diet-treated rats. In conclusion, treatment with a cafeteria diet for 17 weeks in rats mimicked a pre-diabetic state, with ectopic lipid accumulation in the pancreas, and increased the IDE-mediated insulin clearance capability.

The aim of the present work was to evaluate the effects of a grape seed procyanidin extract (GSPE) on proliferation and apoptosis in the pancreatic adenocarcinoma cell line MIA PaCa-2 and identify the components of the extract with higher activity. The effects of the extract were analyzed on the proliferation and apoptosis processes in MIA PaCa-2 cells, as well as in the levels of the apoptosis markers Bcl-2 and Bax, the mitochondrial membrane potential, and reactive oxygen species levels. Finally, the components of the extract with higher effects were elucidated using enriched fractions of the extract and pure compounds. The results showed that GSPE inhibits cell proliferation and increases apoptosis in MIA PaCa-2 cells, which is primarily mediated by the downregulation of the antiapoptotic protein Bcl-2 and the depolarization of the mitochondrial membrane. GSPE also reduced the formation of reactive oxygen species. The component of the extract that possesses the highest antiproliferative and proapoptotic activity was gallic acid. In conclusion, GSPE acts as anticarcinogenic in MIA PaCa-2 cells, with gallic acid as the major single active constituent of the extract.