Nicotinamide phosphoribosyltransferase and prostaglandin H2 synthase 2 are up-regulated in human pancreatic adenocarcinoma cells after stimulation with interleukin-1.

Human pancreatic cancer is today an almost incurable disease with a 5-year survival rate of <5%. Chronic inflammation in the tumor region is often associated with cancer progression. In pancreatic tumors, the pro-inflammatory cytokine IL-1 has been found to affect the development of chemoresistance in this cancer type. In a search for new therapeutic targets we investigated the effect of this pro-inflammatory mediator on pancreatic cancer protein expression. Therefore, the human pancreatic adenocarcinoma cell line Colo357 was subjected to proteomic analysis after stimulation with IL-1 using 2D gel electrophoresis and mass spectrometry. We detected 11 spots as being differentially expressed after stimulation with IL-1 representing 11 different proteins. Among them, nicotinamide phosphoribosyltransferase (NAMPT) and prostaglandin H2 synthase 2 (PGHS-2) are crucial proteins whose expression in Colo357 is increased by IL-1. This study is the first one demonstrating an up-regulation of NAMPT in a tumor model for human pancreatic cancer. Several clinical trials using selective PGHS-2 or NAMPT inhibitors alone did not lead to an improvement in clinical outcome. Against the background of a high cardiovascular risk associated with PGHS-2-specific pharmacological inhibitors, we recommend a combinatory treatment with selective NAMPT and PGHS-2 inhibitors. This might overcome the limitations associated with PGHS-2 inhibitors since agents at low doses and with complementary mechanisms will be used. Such combined administration should positively affect the balance between risk and benefit in fighting the interplay of tumor-associated pancreatic inflammation and carcinogenesis in high-risk patients with pancreatic neoplasia.

Glycated albumin (Amadori product) induces activation of MAP kinases in monocyte-like MonoMac 6 cells.

Increased levels of glycated, Amadori-modified albumin are a risk factor for diabetic vascular disorders. Glycated albumin binds to specific receptors and induces cellular signaling pathways, the complexity of which is largely unknown. Binding of glycated albumin to MonoMac 6 cells leads to an activation of MAPK p44/42 (ERK1/2) and p38 with subsequent translocation of NF-kappaB into the nucleus. The activation of MAPK is in part mediated by protein kinase C activation, but a PKC-independent pathway via MEK-1 is also involved. Protein tyrosine kinases do not play a role in the activation of NF-kappaB. The results may have pathophysiological significance, because the MonoMac 6 cell line is not greatly different from blood monocytes.

Nucleophosmin is a component of the fructoselysine-specific receptor in cell membranes of Mono Mac 6 and U937 monocyte-like cells.

The monocyte-like cell lines Mono Mac 6 (MM6) and U937 bind Amadori-modified proteins via fructoselysine (FL)-specific sites with molar masses of 110, 150 and 200 kDa, which can specifically be isolated by an affinity method with magnetobeads coated with glycated polylysine. Using Western blots developed with different anti-nucleophosmin antisera, MS-analysis and immunohistochemistry, we show that the nucleolar protein nucleophosmin is also localized in the cell membrane and is part of the 150- and 200-kDa membrane protein fractions of FL-specific binding membrane proteins. This is the first evidence that nucleophosmin is not only existing in the nucleolus and cytoplasm, but also, like nucleolin, is in the cell membrane.

EGCG downregulates IL-1RI expression and suppresses IL-1-induced tumorigenic factors in human pancreatic adenocarcinoma cells.

Human pancreatic cancer is currently one of the fifth-leading causes of cancer-related mortality with a 5-year survival rate of less than 5%. Since pancreatic carcinoma is largely refractory to conventional therapies, there is a strong medical need for the development of novel and innovative therapeutic strategies. Increasing evidence suggests an association of carcinogenesis and chronic inflammation. Because IL-1 plays a crucial role in inflammation-associated carcinogenesis, we analyzed the biological effects of IL-1 and its modulation by the chemopreventive green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) in the human pancreatic adenocarcinoma cell line Colo357. Proinflammatory IL-6 and PGHS-2 as well as proangiogenic IL-8 and VEGF were induced by IL-1, whereas the secretion of invasion-promoting MMP-2 remained unaffected. IL-1 responsiveness and constitutive MMP-2 release in Colo357 were downregulated by EGCG in a dose- and time-dependent manner. Moreover, EGCG reduced cell viability via induction of apoptosis in Colo357. Since EGCG effects on cytokine production precede reduction in cell viability, we hypothesize that these findings are not only a result of cell death but also depend on alterations in the IL-1 signaling cascade. In this context, we found for the first time an EGCG-induced downregulation of the IL-1RI expression possibly being caused by NF-κB inhibition and causative for its inhibitory action on the production of tumorigenic factors. Thus, our data might have future clinical implications with respect to the development of novel approaches as an adjuvant therapy in high-risk patients with human pancreatic carcinoma.