allopurinol and Pancreatic-Neoplasms

Major histocompatibility complex class I-related chain A and B (MICA/B) are two stress-inducible ligands that bind the immunoreceptor NKG2D and play an important role in mediating the cyotoxicity of NK and T cells. In this study, we sought to study MICA/B expression in pancreatic cancer and to determine whether and how genotoxic drugs such as gemcitabine can affect MICA/B expression and natural killer cytotoxity.. Seven pancreatic cancer cell lines were analyzed for MICA/B expression by flow cytometry and for their sensitivity to NK-92 cell killing by a 51Cr release assay. MICA/B expression in tumor tissues and sera of pancreatic cancer was analyzed by immunohistochemical staining (IHC) and ELISA, respectively.. Two MICA/B-positive cell lines were sensitive to the cytotoxic activity of NK-92 cells. Other two MICA/B-positive cell lines and three MICA/B-negative cell lines were resistant to NK-92 cell killing. MICA/B expression was positive in 17 of 25 (68%) pancreatic ductal adenocarcinomas but not in normal pancreatic ductal epithelial cells. Serum MICA/B levels were significantly elevated in patients with pancreatic adenocarcinomas but did not correlate with the stage of pancreatic cancer and patient survival. Gemcitabine therapy led to increased serum MICA levels in 6 of 10 patients with detectable serum MICA. Allopurinol, an inhibitor of xanthine oxidoreductase that converts xanthine to uric acid, blocked uric acid production, MICA/B expression, and sensitivity to NK-92 cell killing toward a PANC-1 cancer cell line exposed to radiation and two genotoxic drugs, gemcitabine and 5-fluorouracil.. The levels of MICA/B expression in serum and tissue of pancreatic cancer are elevated. DNA damage-induced MICA/B expression is mediated through increased uric acid production.

Topics: Adult; Aged; Aged, 80 and over; Allopurinol; Antimetabolites, Antineoplastic; Carcinoma, Pancreatic Ductal; Cell Death; Cell Line, Tumor; Cytotoxicity, Immunologic; Deoxycytidine; DNA Damage; Female; Gallbladder Neoplasms; Gemcitabine; Gene Expression; Histocompatibility Antigens Class I; Humans; Kaplan-Meier Estimate; Killer Cells, Natural; Liver Neoplasms; Male; Middle Aged; Pancreatic Neoplasms; Peritoneal Neoplasms; Uric Acid; Xanthine Dehydrogenase

The death rate for pancreatic cancer approximates the number of new cases each year, and when diagnosed, current therapeutic regimens provide little benefit in extending patient survival. These dire statistics necessitate the development of enhanced single or combinatorial therapies to decrease the pathogenesis of this invariably fatal disease. Melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) is a potent cancer gene therapeutic because of its broad-spectrum cancer-specific apoptosis-inducing properties as well as its multipronged indirect antitumor activities. However, pancreatic cancer cells show inherent resistance to mda-7/IL-24 that is caused by a block of translation of mda-7/IL-24 mRNA in these tumor cells. We now reveal that a dietary agent perillyl alcohol (POH) in combination with Ad.mda-7 efficiently reverses the mda-7/IL-24 "protein translational block" by inducing reactive oxygen species, thereby resulting in mda-7/IL-24 protein production, growth suppression, and apoptosis. Pharmacologic inhibitor and small interfering RNA studies identify xanthine oxidase as a major source of superoxide radical production causing these toxic effects. Because both POH and Ad.mda-7 are being evaluated in clinical trials, combining a dietary agent and a virally delivered therapeutic cytokine provides an innovative approach for potentially treating human pancreatic cancer.

Topics: Adenoviridae; Antineoplastic Agents; Apoptosis; Cell Growth Processes; Cell Line, Tumor; Combined Modality Therapy; Down-Regulation; Genetic Therapy; Genetic Vectors; Humans; Interleukins; Monoterpenes; Pancreatic Neoplasms; Polyribosomes; Reactive Oxygen Species; RNA, Messenger; RNA, Small Interfering; Xanthine Oxidase

The extracellular matrix (ECM) facilitates pancreatic cancer cells survival, which is of central importance for pancreatic adenocarcinoma that is highly fibrotic. Here, we show that reactive oxygen species (ROS) mediate the prosurvival effect of ECM in human pancreatic cancer cells. Fibronectin and laminin stimulated ROS production and NADPH oxidase activation in pancreatic cancer cells. Both pharmacological and molecular approaches show that fibronectin stimulated ROS production through activation of NADPH oxidase and NADPH oxidase-independent pathways and that 5-lipoxygenase (5-LO) mediates both these pathways. Analyses of the mechanisms of ROS production by ECM proteins and growth factors indicate that activation of NADPH oxidase (Nox4) is a common mechanism employed both by ECM proteins and growth factors to increase ROS in pancreatic cancer cells. We also found that Nox4 is present in human pancreatic adenocarcinoma tissues and that these tissues display membrane NADPH oxidase activity. ECM proteins and growth factors activate NADPH oxidase through different mechanisms; in contrast to ECM proteins, growth factors activate NADPH oxidase through 5-LO-independent mechanisms. Inhibition of 5-LO or NADPH oxidase with pharmacological inhibitors of these enzymes and with Nox4 or 5-LO antisense oligonucleotides markedly stimulated apoptosis in cancer cells cultured on fibronectin. Our results indicate that ROS generation via 5-LO and downstream NADPH oxidase mediates the prosurvival effect of ECM in pancreatic cancer cells. These mechanisms may play an important role in pancreatic cancer resistance to treatments and thus represent novel therapeutic targets.

Topics: Adenocarcinoma; Antioxidants; Apoptosis; Arachidonate 5-Lipoxygenase; Cell Line, Tumor; Cell Survival; Collagen Type I; Extracellular Matrix; Fibronectins; Humans; Laminin; Lipoxygenase Inhibitors; NADPH Oxidase 4; NADPH Oxidases; Nitric Oxide Synthase; Oligonucleotides, Antisense; Pancreatic Neoplasms; Reactive Oxygen Species; Xanthine Oxidase

A large fraction of an islet graft can be lost early following allotransplantation from various non specific mechanisms including oxidative stress. Overexpression of antioxidant enzymes could confer a beneficial effect on islets exposed to reactive oxygen and nitrogen species. We examined the viability of beta cells driven to overexpress glutathione peroxidase (GPx) and exposed to a superoxide donor (hypoxanthine/xanthine oxidase HX/XO) and a nitric oxide donor (3-morpholinosydnonimine SIN-1).. Cultured INS-1 rat-derived insulin-secreting cells were transfected by an E1-deleted adenovirus carrying GPx cDNA (AdGPx). Additional experiments were performed with an adenovector carrying Cu/Zn superoxide dismutase cDNA (AdSOD). Cellular viability was tested by the WST-1 colorimetric assay and functionality by static incubation.. AdGPx increased GPx activity within 48 hours from 0 (untransfected cells) to 60 +/- 11 U/g (cells transfected at an MOI of 25: 1). GPx overexpression significantly reduced cytotoxicity induced by HX/XO from 10.81 +/- 1.41 to 5.42 +/- 2.62% at 10 mU/ml and from 61.19 +/- 4.17 to 52.9 +/- 4.39% at 20 mU/ml (p=0.0002, transfected cells vs control cells). Doses of SIN-1 from 600 to 1000 micromol/l resulted in cytotoxicity ranging from 17.66 +/- 3.48 to 45.97 +/- 6.48% in control cells and from 5.65 +/- 1.37 to 35.80 +/- 5.59% in AdGPx transfected cells (p=0.015). The combination of AdGPx and AdSOD did not exhibit any synergistic cytoprotective effect. Control cells exposed to a HX/XO stress exhibited a reduction in glucose-theophylline stimulated insulin secretion by half, while stressed GPx overexpressing-cells maintained the same insulin secretion level than non-stressed cells.. Adenoviral-induced overexpression of GPx enhances the resistance of a rat beta cell line to both reactive oxygen (ROS) and reactive nitrogen species (RNS) cytotoxicity. Transposition of these findings to human islet transplantation with a clinically-relevant procedure deserves further investigations.

Topics: Adenoviridae; Animals; Cattle; Cell Survival; DNA, Complementary; Enzyme Inhibitors; Glucose; Glutathione Peroxidase; Hypoxanthine; Insulin; Insulin Secretion; Insulinoma; Molsidomine; Oxidative Stress; Pancreatic Neoplasms; Rats; Recombinant Proteins; Superoxide Dismutase; Transfection; Tumor Cells, Cultured; Xanthine Oxidase

Human beta cells exhibit increased resistance against nitric oxide (NO) radicals as compared with rodent islet cells. Here we tested whether endogenous heat shock protein 70 (hsp70) accounts for the resistance of human cells. Stable transfection of the human beta cell line CM with an antisense hsp70 mRNA-expressing plasmid (ashsp70) caused selective suppression (>95%) of spontaneously expressed hsp70 but not of hsc70 or GRP75 protein. ashsp70 transfection abolished the resistance of CM cells to the NO donors (Z)-1- (2-(2-aminoethyl)-N-(2-ammonioethyl)amino)diazen-1-ium -1,2-diolate and sodium nitroprusside and increased the proportions of necrotic cells 3-5-fold (p < 0.05) and of apoptotic cells about 2-fold (p < 0.01). Re-induction of hsp70 expression by heat shock re-established resistance to NO toxicity. hsp70 did not exert its protective effect at the level of membrane lipid integrity because radical induced lipid peroxidation appeared independent of hsp70 expression. However, after NO exposure only hsp70-deficient cells showed significantly decreased mitochondrial activity, by 40-80% (p < 0.01). These results suggest a key role of hsp70 in the natural resistance of human beta cells against NO induced injury, by preserving mitochondrial function. These findings provide important implications for the development of beta cell protective strategies in type 1 diabetes and islet transplantation.

Topics: Animals; Cell Line; Flow Cytometry; Glucose; Hot Temperature; HSP70 Heat-Shock Proteins; Humans; Hypoxanthine; Immunity, Innate; Indicators and Reagents; Insulinoma; Islets of Langerhans; Mice; Nitric Oxide; Nitroprusside; Oxygen Consumption; Pancreatic Neoplasms; Plasmids; Rats; Reactive Oxygen Species; RNA, Antisense; Time Factors; Transfection; Tumor Cells, Cultured; Xanthine Oxidase

In attempts to increase fluorouracil (FU) activity by pharmacomodulation, most attention has been paid to FU activation pathways without consideration of the presence and possible role of FU catabolism in the target tumoral cell itself. The first step in the catabolism of FU is hydrogenation by the enzyme dihydropyrimidine dehydrogenase (DPD). The purpose of the present study was to test the DPD-inhibitory effects of several agents whose use as FU biomodulators has been clinically established: cisplatin, hydroxyurea, dipyridamole, and allopurino. Five cancer cell lines of human origin were used. Dipyridamole and hydroxyurea were the only modulators for which an augmentation in FU cell-growth inhibition (MTT test) was clearly evident for the whole panel of cell lines investigated (P<1.10(-4) and P=0.005, respectively). With dipyridamole the efficacy of FU was multiplied by a factor of around 5. Allopurinol and cisplatin had no obvious effect on cellular DPD activity (biochemical method). For dipyridomole and hydroxyurea, DPD activity showed a more or less marked concentration-related inhibition according to the cell line tested. Only dipyridamole produced reductions in FU IC50 values (50% growth-inhibitory concentrations), i.e., potentiation of FU cytotoxicity, that were significantly related to inhibition of cellular DPD activity. This DPD-mediated interaction between dipyridamole and FU is a new finding that could be important for a better understanding of FU-dipyridamole combination chemotherapy.

Topics: Allopurinol; Antimetabolites, Antineoplastic; Antineoplastic Agents; Breast Neoplasms; Carcinoma; Cell Division; Cisplatin; Dihydrouracil Dehydrogenase (NADP); Dipyridamole; Dose-Response Relationship, Drug; Drug Interactions; Female; Fluorouracil; Head and Neck Neoplasms; Humans; Hydroxyurea; Oxidoreductases; Pancreatic Neoplasms; Platelet Aggregation Inhibitors; Tumor Cells, Cultured

Topics: Adenosine; Allopurinol; Cell Separation; Colony Count, Microbial; Diabetes Mellitus, Type 1; Drug Contamination; Glutathione; Humans; Insulin; Islets of Langerhans Transplantation; Organ Preservation Solutions; Pancreatic Neoplasms; Postoperative Complications; Pseudomonas; Raffinose; Solutions; Staphylococcus

Topics: Adenoma, Bile Duct; Adenosine; Adult; Allopurinol; Bile Duct Neoplasms; Carcinoma, Hepatocellular; Colonic Neoplasms; Duodenal Neoplasms; Duodenum; Female; Glutathione; Humans; Insulin; Intestine, Small; Liver Neoplasms; Liver Transplantation; Male; Middle Aged; Organ Preservation; Organ Preservation Solutions; Pancreas Transplantation; Pancreatic Neoplasms; Raffinose; Solutions

Topics: Aged; Allopurinol; Diagnosis, Differential; Gout; Humans; Male; Neoplasms; Pancreatic Neoplasms; Vasculitis