No abstract

Sulfasalazine is commonly used as an anti inflammatory agent and is known as a potent inhibitor of NF-B. Some pancreatic carcinomas are characterized by a constitutively elevated NF-B activity accounting for chemoresistance. To elucidate whether blockade of NF-B activity with sulfasalazine is suitable for overcoming this chemoresistance in vivo, we employed a mouse model with subcutaneously xenotransplanted human Capan-1 pancreatic carcinoma cells. Fourteen days upon tumor inoculation, animals were randomized in 6 groups, receiving no treatment, treatment with gemcitabine or with etoposide, either alone or in combination with sulfasalazine, or with sulfasalazine alone. Two therapy regimens were given with a 7-day interval in between. Upon treatment with etoposide or gemcitabine alone, tumor sizes were moderately reduced to 65-68% and 50 -65%, respectively, as compared to untreated tumors. Sulfasalazine alone only decreased temporarily the tumor sizes. Sulfasalazine in combination with gemcitabine showed only partially higher reduction in tumor sizes than gemcitabine alone, whereas the combination with etoposide reduced significantly the tumor sizes in all experiments (down to 20%). TUNEL-staining showed higher numbers of apoptotic cells in tumors from the combination groups, in particular with etoposide, and proliferation as indicated by Ki67 staining was strongly reduced. Furthermore, combined treatment of sulfasalazine with the cytostatic drugs led to a decreased blood vessel density. Immunohistochemical staining of the activated p65 subunit showed that sulfasalazine treatment abolished the basal NF-B activity in tumor xenografts. These data imply that the well established anti-inflammatory drug sulfasalazine sensitizes pancreatic carcinoma cells to anti cancer drugs, in particular to etoposide in vivo by inhibition of NF-B. This combined chemotherapy offers great potential for improved anti-tumor responses in pancreatic carcinomas.

The early response gene IEX-1 is involved in the regulation of cellular growth and survival, and its expression is related to stress-, growth-and deathinducing signals. Addressing the role of IEX-1 in the promotion of apoptosis, we investigated the effect of IEX-1 on nuclear factor-jB (NF-jB) activation. Stably transfected HEK-293 cells conditionally overexpressing IEX-1 exhibit decreased levels of NF-jB activity, either basal or TNFa induced, as shown by gel-shift and luciferase reporter gene assay. Furthermore, activated p65 accumulated in the nuclei of 293 cells to a lower degree, if IEX-1 expression was increased. This inhibited NF-jB activation was preceded by an altered turnover of IjBa and phospho-IjBa. In addition, IEX-1 expression also inhibited the activity of the 26S-proteasome, as shown by a fluorometric proteasome assay. Conversely, disruption of IEX-1 expression in 293 cells by stable transfection with specific anti-IEX-1 hammerhead ribozymes increased NF-jB activity, and accelerated the degradation of IjBa. Along with these opposite effects of IEX-1 expression and IEX-1 disruption on NF-jB activation, the sensitivity of 293 cells towards various apoptotic stimuli also changed. In contrast to ribozymetransduced 293 cells that were significantly less sensitive to apoptosis, this sensitivity was enhanced if IEX-1 expression was increased. Our data suggest that IEX-1 -itself an NF-jB target gene -inhibits the activation of this transcription factor, and hereby may counteract the antiapoptotic potential of NF-jB.

The autocrine secretion of IL-1beta contributes to a constitutively increased NF-kappaB activity in PDAC cells along with a chemoresistant phenotype.

The study clearly shows that the AQC-database offers a wide variety of possibilities for quality assurance and scientific analyses. Our data demonstrate that laparoscopic procedures clearly increased from 2001 to 2006. Appendectomies were mainly performed by residents and junior faculty members. Laparoscopic appendectomy is a safe procedure with a low complication rate and should be applied as a teaching operation during the surgical training.