Advancements in pancreatic neuroendocrine tumors.

Pancreatic neuroendocrine tumors (PanNETs) have increased in incidence in the USA over the last 20 years. Although PanNETs are often misconceived as being indolent tumors as they have a far more favorable prognosis over pancreatic adenocarcinoma, roughly 60-70% of patients have metastatic disease at the time of diagnosis due to presentation late in the disease process. While improvements in imaging modalities allow for early detection and better tumor localization, recent advancements in basic science, as well as surgical and medical management of PanNETs have further improved the prognosis. The mainstay of therapy for localized PanNETs is surgical intervention, which has become safer and is slowly shifting towards a more minimally invasive approach. However, the prognosis still remains relatively bleak for patients with unresectable disease. Fortunately, novel molecular targeted therapies, such as everolimus and sunitinib, have recently come into the limelight and have shown significant promise for the treatment of locally advanced and metastatic disease.

Secretory phospholipase A2 mediates human esophageal adenocarcinoma cell growth and proliferation via ERK 1/2 pathway.

BACKGROUND/AIM: Secretory phospholipase-A2 (sPLA2) mediates growth and proliferation of human esophageal adenocarcinoma cells (HEAC). Two major molecular pathways of cancer growth regulation include extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase-B (AKT). Phospholipase enzymes have been demonstrated to significantly influence these two growth regulating pathways in other tumor cells. We hypothesize sPLA2 to mediate HEAC growth control through ERK 1/2 and AKT. MATERIALS AND METHODS: Verified HEAC (FLO-1), treated with either the mitogen-activated protein kinase kinase selective inhibitor (PD98059) or with group IIa sPLA2-specific inhibitor, were assessed for ERK1/2 phosphorylation and AKT activation after tumor necrosis factor-alpha stimulation, as well as for viability, proliferation, and apoptosis responses. RESULTS: PD98059 significantly inhibited ERK 1/2 activation, reduced cell viability, and reduced proliferation (p<0.05). sPLA2 inhibition attenuated ERK 1/2 activation (p<0.01) but had no effect on AKT activation or apoptosis. CONCLUSION: Specific inhibition of group IIa sPLA2 directly reduces HEAC viability and proliferation by attenuating ERK 1/2 activation with no effect on AKT activation or apoptosis. This may indicate that the mechanism of action of sPLA2 is mainly the induction of growth arrest.

Group IIa sPLA2 inhibition attenuates NF-κB activity and promotes apoptosis of lung cancer cells.

BACKGROUND/AIM: Group IIa secretory phospholipase A2 (sPLA2 IIa) has been implicated in the regulation of metastasis of non-small cell lung cancer (NSCLC) and the present study investigates its contribution to lung cancer growth and progression. PLA2s initiate signaling in several pathways that mediate cell survival including phosphatidylinositol 3-kinase-AKT (PI3K-AKT), p38 mitogen-activated protein kinase (p38 MAPK), extracellular-signal-regulated kinase (ERK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). MATERIALS AND METHODS: Human NSCLC cell lines (A549 and NCI-H358) were treated with a specific sPLA2 IIa inhibitor. Cells were assayed for apoptosis, viability, proliferation and changes in cell morphology. Effects on AKT, p38 MAPK, ERK1/2 and NF-κB signaling pathways were investigated. RESULTS: sPLA2 IIa inhibition reduced proliferation and increased apoptosis. NF-κB activity was attenuated, whereas AKT, ERK1/2, p38 MAPK were variably affected by sPLA2 IIa inhibition. NF-κB inhibitor-associated apoptosis confirmed the dominant role of NF-κB. CONCLUSION: sPLA2 IIa attenuates growth and promotes apoptosis predominantly via its effects on NF-κB activity.

Lung cancer cell invasion and expression of intercellular adhesion molecule-1 (ICAM-1) are attenuated by secretory phospholipase A2 inhibition.

OBJECTIVE: Invasive lung tumors are associated with intercellular adhesion molecule-1 (ICAM-1) expression. Secretory phospholipase A(2) (sPLA(2)) enzymes produce inflammatory mediators that stimulate ICAM-1 expression, and upregulation of PLA(2) activity can enhance metastasis. We hypothesize a link between sPLA(2) activity, ICAM-1 expression, and tumor cell invasion. We propose that inhibition of sPLA(2) modulates ICAM-1 expression in cancer cells and attenuates their invasiveness. METHODS: Human lung adenocarcinoma cells (A549) were treated with an ICAM-1 blocking antibody and assayed for invasion. Lung cancer cells (A549 and H358) were then treated with an sPLA(2) inhibitor and evaluated by immunoblotting for ICAM-1 expression. Next cells (A549) treated with sPLA(2) inhibitor were assayed for invasion. Finally, sPLA(2) messenger RNA and protein expression were evaluated by quantitative reverse-transcriptase polymerase chain reaction and immunofluorescence microscopy, respectively. Statistical analysis was performed by the Student t test or analysis of variance, as appropriate. RESULTS: Antibody blockade of ICAM-1 decreased lung cancer cell invasion. sPLA(2) inhibition significantly reduced ICAM-1 expression and invasion. sPLA(2) inhibition also significantly decreased sPLA(2) mRNA expression and immunofluorescent staining of sPLA(2). CONCLUSIONS: sPLA(2) plays a significant role in mediating the inflammatory signals that induce ICAM-1 expression in lung cancer cells. Inhibition of the enzyme can significantly decrease ICAM-1 expression and subsequent cancer cell invasion. This lays the groundwork for further investigation into the cellular mechanisms of sPLA(2) and its role in lung cancer.

Statin therapy attenuates growth and malignant potential of human esophageal adenocarcinoma cells.

OBJECTIVES: Esophageal adenocarcinoma is an aggressive malignancy generally diagnosed after metastatic spread and currently lacks effective medical therapy. Expression of intracellular adhesion molecule-1 (ICAM-1) is an adverse prognostic indicator in various human tumor cells and contributes significantly to their metastatic potential. Statin therapy reduces circulating ICAM-1 levels in patients with coronary heart disease and is associated with reduction in progression from Barrett esophagus to esophageal adenocarcinoma. We hypothesize that statin therapy may attenuate growth and malignant potential via ICAM-1 expression and nuclear factor-kappa beta activation in human esophageal adenocarcinoma cells. METHODS: Verified human esophageal adenocarcinoma cells (FLO-1) were treated with simvastatin, atorvastatin, or pravastatin (10-, 30-, and 50-µmol/L concentrations). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide viability, 5-bromo-2'-deoxyuridine proliferation, or annexin V apoptosis assays were performed, or cells were stimulated with tumor necrosis factor-alpha and collected for immunoblotting and flow cytometry. RESULTS: Simvastatin decreased cell viability and proliferation while increasing apoptosis in a dose-dependent manner (P < .05). Simvastatin attenuated total cellular and cell-surface ICAM-1 expression as well as nuclear factor-kappa beta activation (P < .05). Atorvastatin had mild effects and pravastatin had essentially no effect on growth and metastatic potential of these cells. CONCLUSIONS: We demonstrate that treatment of human esophageal adenocarcinoma cells with simvastatin attenuates growth, by decreasing cell viability, decreasing cell proliferation, and increasing apoptosis, and attenuates metastatic potential, by decreasing expression of key metastatic markers. These findings identify simvastatin as a potential therapeutic and chemopreventive modality to thwart the progression of esophageal adenocarcinoma.

DITPA, a thyroid hormone analog, reduces infarct size and attenuates the inflammatory response following myocardial ischemia.

BACKGROUND: Thyroid hormone can have positive effects on the cardiovascular system but its therapeutic potential is limited secondary to its adverse effects. DITPA (3,5-diiodothyroproprionic acid) is a synthetic thyroid hormone analog with positive inotropic effects similar to thyroid hormone but with minimal systemic effects. DITPA has previously been shown to reduce pathologic remodeling and improve cardiac output following myocardial infarction; however, few studies have examined the role of DITPA in determining infarct size or the early inflammatory response following myocardial ischemia. We examined the role of DITPA in the acute phase following infarction. MATERIALS AND METHODS: Mice were subjected to surgical induction of myocardial infarction and were then randomized to receive daily injections of DITPA or vehicle control. After 3 d, animals were sacrificed and infarct size was determined by H and E staining. Myocardial macrophage and neutrophil accumulation was determined by immunofluorescent staining. Immunoblotting and enzyme-linked immunosorbent assay (ELISA) were used to examine the levels of intercellular adhesion molecule-1 (ICAM-1), keratinocyte-derived chemokine (KC), monocyte chemoattractant protein (MCP-1), and interleukin 6 (IL-6) in homogenates from the ischemic tissue. RESULTS: Compared with vehicle control, DITPA treated animals had smaller infarcts (52.1%±5.7% versus 37.3%±3.6%, P<0.05) and decreased macrophage (32±4 versus 14±1 cells/HPF, P<0.05, and neutrophil (14±2 versus 7±1 cells/HPF, P<0.05) accumulation. Myocardial ICAM-1, (2.37±0.4 versus 1.1±0.2, P<0.05), KC levels (33.32±12.4 pg/mg, versus 21.24±8.9 pg/mg, P<0.05), and IL-6 levels (112.3±78 pg/mg versus 37.3±25.9 pg/mg, P<0.05) were also reduced in the DITPA treated group, while MCP-1 levels were equivalent between groups. CONCLUSIONS: Treatment with DITPA attenuates the acute inflammatory response and reduces myocardial infarct size. The reduction in myocardial ICAM-1, KC, and IL-6 levels in the DITPA group was associated with a decrease in macrophage and neutrophil accumulation.

Cytokine expression profile in human lungs undergoing normothermic ex-vivo lung perfusion.

BACKGROUND: A donor lung shortage prevents patients from receiving life-saving transplants. Ex-vivo lung perfusion (EVLP) is a viable means of expanding the donor pool by evaluating and potentially improving donor lung function. The metabolic and inflammatory effects of EVLP on human lung tissue are currently unknown. We sought to establish representative cytokine expression in human donor lungs meeting acceptable lung transplant criteria after prolonged normothermic EVLP. METHODS: Seven single human lungs not meeting traditional transplantation criteria for various reasons underwent normothermic EVLP. Lungs were perfused with deoxygenated colloid, rewarmed, and ventilated per standard protocol. Lung function was evaluated every hour. Biopsies were taken at 1, 6, and 12 hours. Inflammatory cytokines were quantitatively measured using a human cytokine magnetic bead-based multiplex assay. RESULTS: All lungs met traditional transplant criteria after EVLP. The partial pressure of arterial oxygen and physiologic lung function significantly improved (p<0.05). No pulmonary edema was formed, and histology demonstrated no evidence of acute lung injury. Interleukin (IL)-6, IL-8, granulocyte colony-stimulating factor, and monocyte chemotactic protein-1 were upregulated, while granulocyte macrophage colony-stimulating factor was downregulated during EVLP (p<0.05). IL-1ß, IL-4, IL-7, IL-12, interferon-γ, macrophage inflammatory protein-1ß, and tumor necrosis factor-α were detectable and unchanged. CONCLUSIONS: Ex-vivo lung perfusion demonstrates the ability to improve oxygenation and physiologic lung function in donor lungs unacceptable for transplantation without injury to the lung. We establish here a cytokine expression profile in human lungs undergoing normothermic EVLP. These data can be used in the future to explore novel targeted therapies for ischemia-reperfusion injury.

Secretory phospholipase A2 inhibition attenuates intercellular adhesion molecule-1 expression in human esophageal adenocarcinoma cells.

BACKGROUND: Esophageal adenocarcinoma is an aggressive malignancy, with most patients succumbing to metastatic disease. The presence of intercellular adhesion molecule-1 (ICAM-1) in these cancer cells contributes to their metastatic potential. The ICAM-1 production in other cell types is stimulated by the actions of phospholipase enzymes. We hypothesize that inhibition of the enzyme secretory phospholipase A2 (sPLA2), which contributes to the growth potential of normal esophageal mucosa and esophageal cancer cells, may attenuate ICAM-1 production and nuclear factor-kappa beta activation in human esophageal adenocarcinoma cells. METHODS: The FLO-1 verified human esophageal adenocarcinoma cells were treated with 5-(4-benzyloxyphenyl)-4S-(7-phenylheptanoylamino) pentanoic acid, a specific inhibitor of group IIa sPLA2 (5 µM, 10 µM, and 15 µM doses), followed by tumor necrosis factor-alpha stimulation (20 ng/mL). Cells and medium were collected and analyzed by immunoblotting, flow cytometry, and enzyme-linked immunosorbent assay. Statistical analysis was performed using analysis of variance with the Fisher's least significant difference post-hoc test. RESULTS: Treatment with sPLA2 inhibitor attenuated total cellular ICAM-1 expression in a dose-dependent manner (p<0.005). Cell-surface and secreted ICAM-1 expression decreased significantly with sPLA2 inhibitor treatment (p<0.001 and p<0.05, respectively). sPLA2 inhibition attenuated nuclear factor-kappa beta activation dose-dependently (p<0.05). CONCLUSIONS: Esophageal adenocarcinoma has significant metastatic potential, and inhibiting its metastasis would significantly advance the treatment of this disease. We demonstrate here that treatment of human esophageal adenocarcinoma cells with sPLA2 inhibitor attenuates the expression of ICAM-1, a marker of metastatic potential, and nuclear factor-kappa beta activation, suggesting a common pathway between the two. These findings identify inhibition of sPLA2 as a potential therapeutic target for esophageal adenocarcinoma.

Hemolysis, elevated liver enzymes, and low platelets syndrome: when is surgical help needed?

BACKGROUND: Life-threatening hemorrhage is a rare event in hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome. Epidemiologic data are lacking to predict patients at risk for hemorrhage requiring surgical consultation. We sought to identify early clinical predictors of hemorrhagic complications in patients at risk for HELLP syndrome. METHODS: Patients at risk for HELLP syndrome from 1997 to 2007 were identified retrospectively. Variables evaluated in at-risk women were maternal age, gestational history, hepatic transaminase levels, and platelet count. Multiple logistic regression analysis was used to identify independent predictors of poor maternal outcomes, which were defined as hemorrhage requiring transfusion of blood products, need for surgical intervention, hepatic rupture, and death. RESULTS: A total of 109 at-risk women were identified. Adverse outcomes included transfusions (18%), hemorrhage interventions (8%), damage control laparotomy (2.8%), and hepatic rupture (2.8%). Maternal and perinatal mortality were .9% and 3.7%, respectively. Median transfusion requirements for women with hepatic rupture were 56 U of packed red blood cells, 26 U of fresh-frozen plasma, 18 U of platelets, and 6 U of cryoprecipitate. Multiple logistic regression analysis showed previous gestations (P = .002), platelet count (P = .01), and aspartate aminotransferase level increase (P = .04) were independent predictors of life-threatening hemorrhage. Previous gestations increased the risk of adverse outcome 3-fold. CONCLUSIONS: Identifiable risk factors predictive of major hemorrhage are thrombocytopenia (<100,000 cells/microL), increase of aspartate aminotransferase level greater than 70 IU/L, and previous gestations.

The sesquiterpene lactone parthenolide in combination with docetaxel reduces metastasis and improves survival in a xenograft model of breast cancer.

Parthenolide, a sesquiterpene lactone, shows antitumor activity in vitro, which correlates with its ability to inhibit the DNA binding of the antiapoptotic transcription factor nuclear factor kappaB (NF-kappaB) and activation of the c-Jun NH(2)-terminal kinase. In this study, we investigated the chemosensitizing activity of parthenolide in vitro as well as in MDA-MB-231 cell-derived xenograft metastasis model of breast cancer. HBL-100 and MDA-MB-231 cells were used to measure the antitumor and chemosensitizing activity of parthenolide in vitro. Parthenolide was effective either alone or in combination with docetaxel in reducing colony formation, inducing apoptosis and reducing the expression of prometastatic genes IL-8 and the antiapoptotic gene GADD45beta1 in vitro. In an adjuvant setting, animals treated with parthenolide and docetaxel combination showed significantly enhanced survival compared with untreated animals or animals treated with either drug. The enhanced survival in the combination arm was associated with reduced lung metastases. In addition, nuclear NF-kappaB levels were lower in residual tumors and lung metastasis of animals treated with parthenolide, docetaxel, or both. In the established orthotopic model, there was a trend toward slower growth in the parthenolide-treated animals but no statistically significant findings were seen. These results for the first time reveal the significant in vivo chemosensitizing properties of parthenolide in the metastatic breast cancer setting and support the contention that metastases are very reliant on activation of NF-kappaB.