Both pancreatic cancer patient specimens with corresponding normal pancreatic tissue from the same patient were stained with anti-xCT antibody by immunofluorescence. Use of a rabbit IgG antibody as a negative control indicated that the xCT staining was not due to non-specific binding of immunoglobulins. In the normal pancreatic tissues, xCT protein expression www.selleckchem.com/products/z-vad-fmk.html was primarily localised to ductal cells, not acinar cells (Figure 4). Importantly, the pancreatic ductal adenocarcinomas exhibited overexpression of xCT protein. The distinct histological features of the two pancreatic cancer specimens, including atypical epithelial architecture, papillary folding, and intraluminal cell shedding, indicated that these specimens were likely invasive pancreatic ductal adenocarcinomas.

The upregulated expression of xCT protein in the pancreatic cancer tissues suggest that elevated xc? transporter expression plays a role in the pathogenesis of pancreatic cancer. Figure 4 Expression of the xc? transporter in primary human pancreatic cancer specimens. Immunofluorescence for xCT (red) and DAPI (blue) in normal ductal cells, normal acinar cells, and pancreatic ductal adenocarcinoma cells from two primary human pancreatic … A positive correlation exists between the expression level of xCT and resistance towards GEM Thus far we have obtained evidence that elevated xc? transporter expression can enhance pancreatic cancer cell growth by promoting the uptake of extracellular cystine, which in turn functions to maintain high levels of intracellular GSH to promote cancer cell survival in the presence of oxidative stress.

Among the three pancreatic cancer cell lines used in this study, PANC-1 cells expressed the highest relative level of xCT mRNA compared with that of BxPC-3 and MIA PaCa-2 (Figure 5A), suggesting that PANC-1 cells may exhibit the greatest resistance towards oxidative stress-induced cell death. Gemcitabine, the most common chemotherapeutic agent for the treatment of pancreatic cancer (Maehara et al, 2004), induces cell death through a mechanism that can involve oxidative stress (Maehara et al, 2004; Donadelli et al, 2007). To determine whether a relationship exists between the expression level of the xc? transporter and resistance towards GEM, we treated pancreatic cancer cells with GEM and determined the half maximal inhibitory concentration (IC50) of GEM using neutral red assays. The IC50 of GEM was highest in PANC-1 cells (>50��M) compared with MIA PaCa-2 (~0.03��M) and BxPC-3 (0.01��M) cells (Figure 5B). Brefeldin_A The higher resistance of the PANC-1 cells to GEM may correspond with the higher number of cystine transporters per cell as suggested by relative xCT expression levels.