Oscar J. Hines

Hypoxia-inducible factor 1 regulates vascular endothelial growth factor expression in human pancreatic cancer.

Introduction The microenvironment of low oxygen that is present in human pancreatic cancer in vivo may actively influence tumor growth as well as neovascularization. Aims To determine whether hypoxia-inducible factor 1 (HIF-1) is specifically activated by hypoxia in vitro in pancreatic cancer cells and correlated these findings with tumor specimens. Methodology Hypoxic regulation of vascular endothelial growth factor (VEGF) was studied by northern blot analysis and enzyme-linked immunosorbent assay. Electrophoretic mobility shift assays and western blot analysis were used to demonstrate hypoxic activation of HIF-1. The relationship between HIF-1 and VEGF in human pancreatic cancer specimens was studied by immunohistochemical analysis, northern blot analysis, and in situ hybridization. Results Studies in vivo of human pancreatic cancer tissue showed co-localization of VEGF mRNA, which is produced in ductal cancer cells, and HIF-1&agr; protein, which was detectable in cell nuclei of the same cells. HIF-1&agr; mRNA expression was dramatically upregulated (≈13-fold) in these specimens as well. In vitro, all pancreatic cancer cell lines increased VEGF production when exposed to low oxygen levels, by highly specific activation of HIF-1 DNA binding activity to the VEGF promoter. Cancer cell lines with high constitutive levels of HIF-1&agr; protein were found to produce higher basal levels of VEGF. Conclusion We conclude that HIF-1 is the regulatory link between tumor hypoxia and VEGF production in pancreatic cancer, thus establishing a biochemical pathway between tumor hypoxia and neoangiogenesis in this highly aggressive neoplasm.

Cellular Histone Modification Patterns Predict Prognosis and Treatment Response in Resectable Pancreatic Adenocarcinoma: Results From RTOG 9704

PURPOSE Differences in cellular levels of histone modifications have predicted clinical outcome in certain cancers. Here, we studied the prognostic and predictive value of three histone modifications in pancreatic adenocarcinoma. METHODS Tissue microarrays (TMAs) from two pancreatic adenocarcinoma cohorts were examined, including those from a 195-patient cohort from Radiation Therapy Oncology Group trial RTOG 9704, a multicenter, phase III, randomized treatment trial comparing adjuvant gemcitabine with fluorouracil and a 140-patient cohort of patients with stage I or II cancer from University of California, Los Angeles Medical Center. Immunohistochemistry was performed for histone H3 lysine 4 dimethylation (H3K4me2), histone H3 lysine 9 dimethylation (H3K9me2), and histone H3 lysine 18 acetylation (H3K18ac). Positive tumor cell staining for each histone modification was used to classify patients into low- and high-staining groups, which were related to clinicopathologic parameters and clinical outcome measures. Results Low cellular levels of H3K4me2, H3K9me2, or H3K18ac were each significant and independent predictors of poor survival in univariate and multivariate models, and combined low levels of H3K4me2 and/or H3K18ac were the most significant predictor of overall survival (hazard ratio, 2.93; 95% CI, 1.78 to 4.82) in the University of California, Los Angeles cohort. In subgroup analyses, histone levels were predictive of survival specifically for those patients with node-negative cancer or for those patients receiving adjuvant fluorouracil, but not gemcitabine, in RTOG 9704. CONCLUSION Cellular levels of histone modifications define previously unrecognized subsets of patients with pancreatic adenocarcinoma with distinct epigenetic phenotypes and clinical outcomes and represent prognostic and predictive biomarkers that could inform clinical decisions, including the use of fluorouracil chemotherapy.

Evaluation of the Guidelines for Management of Pancreatic Branch-Duct Intraductal Papillary Mucinous Neoplasm

BACKGROUND & AIMS The 2006 Sendai Consensus Guidelines recommend surgical resection for all suspected branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) greater than 3 cm irrespective of symptoms, and those less than 3 cm with worrisome features. We aimed to evaluate the surgical characteristics of these guidelines retrospectively in pathologically confirmed cases of BD-IPMN. METHODS IPMNs resected at our institution (1995-2006) were classified as main-duct predominant or branch-duct (BD) predominant based on preoperative imaging and postoperative histology. Resected BD-IPMNs were classified histologically: low risk (adenoma, borderline) and high risk (carcinoma in situ or invasive cancer). Clinical data (presence of symptoms, mural nodule, dilated pancreatic duct, and cyst size) were correlated with pathology. RESULTS Between 1995 and 2006, there were 204 patients who underwent surgical resection of pancreatic cysts. Sixty-one patients had IPMN including 31 with BD-IPMN. A total of 74.2% (23 of 31) of BD-IPMNs would have been recommended for surgical resection including 69.2% (18 of 26) of low-risk lesions and 100% (5 of 5) of high-risk lesions. All 8 cases of BD-IPMN that would have been recommended for nonsurgical management were low-risk lesions. The positive predictive value of the guidelines is 21.7% (95% confidence interval, 9.7%-41.9%). The negative predictive value is 100% (95% confidence interval, 67.6%-100.0%). Between 2000 and 2007, 351 patients with likely BD-IPMN were evaluated but not resected. CONCLUSIONS Implementation of the Consensus Guidelines to our single-institution, referral-based, surgical BD-IPMN population would have recommended resection of all histologically high-risk lesions. All lesions recommended for nonsurgical management were histologically low-risk lesions. For presumed BD-IPMNs less than 3 cm, the application of the Consensus Guidelines may reduce the resection rate for low-risk lesions.

Colonic stent vs. emergency surgery for management of acute left-sided malignant colonic obstruction: a decision analysis

BACKGROUND Acute colonic obstruction because of malignancy is often a surgical emergency. Surgical decompression with colostomy with or without resection and eventual re-anastomosis is the traditional treatment of choice. Endoscopic colonic stent insertion effectively decompresses the obstructed colon, allowing for surgery to be performed electively. This study sought to determine the cost-effectiveness of colonic stent vs. surgery for emergent management of acute malignant colonic obstruction. METHODS Decision analysis was used to calculate the cost-effectiveness of two competing strategies in a hypothetical patient presenting with acute, complete, malignant colonic obstruction: (1) emergent colonic stent followed by elective surgical resection and re-anastomosis; (2) emergent surgical resection followed by diversion (Hartmanns procedure) or primary anastomosis. Cost estimates were obtained from a third-party payer perspective. Primary outcome measures were mortality, stoma requirement, and total number of operative procedures. RESULTS Colonic stent resulted in 23% fewer operative procedures per patient (1.01 vs. 1.32 operations per patient), an 83% reduction in stoma requirement (7% vs. 43%), and lower procedure-related mortality (5% vs. 11%). Colonic stent was associated with a lower mean cost per patient (

Influence of hypoxia and neoangiogenesis on the growth of pancreatic cancer

45,709 vs.

Delayed Progression of Pancreatic Intraepithelial Neoplasia in a Conditional KrasG12D Mouse Model by a Selective Cyclooxygenase-2 Inhibitor

49,941). CONCLUSIONS Colonic stent insertion followed by elective surgery appears more effective and less costly than emergency surgery under base-case conditions. This finding remains robust over a wide range of assumptions for clinical inputs in sensitivity analysis. Our findings suggest that colonic stent insertion should be offered, whenever feasible, as a bridge to elective surgery in patients presenting with malignant colonic obstruction.

The Notch Signaling Pathway Is Related to Neurovascular Progression of Pancreatic Cancer

As with other solid tumors, the growth and metastasis of pancreatic cancer is critically dependent on tumor angiogenesis. A major stimulus for a tumors recruitment of additional blood vessels is cellular hypoxia, a condition which is especially pronounced in this neoplasm. Hypoxia induces transcriptional activation of genes that alter cellular metabolism and promote neoangiogenesis. Pancreatic cancer cells have demonstrated activation of such adaptive pathways even in the absence of hypoxia. A highly-angiogenic response in this neoplasm correlates with increased tumor growth, increased metastasis, and decreased survival. Pancreatic cancers expressing high levels of vascular endothelial growth factor, a potent pro-angiogenic cytokine, also have a higher incidence of metastasis and poorer prognosis. Pancreatic cancer cells uniquely express receptors for vascular endothelial growth factor, indicating a role for an autocrine loop in tumor proliferation and invasion. Multiple experimental anti-angiogenic strategies, many of which target vascular endothelial growth factor, reduce pancreatic cancer growth, spread, and angiogenesis. Anti-angiogenic treatments for pancreatic cancer will likely be most effective when used as an integral part of a combination chemotherapeutic regimen.

PGE2 is generated by specific COX-2 activity and increases VEGF production in COX-2-expressing human pancreatic cancer cells

Pancreatic ductal adenocarcinomas are thought to arise from noninvasive, intraductal precursor lesions called pancreatic intraepithelial neoplasias (PanIN). The study of PanINs holds great promise for the identification of early detection markers and effective cancer-preventing strategies. Cyclooxygenase-2 (COX-2) represents an intriguing target for therapeutic and preventive approaches in various human malignancies. The aim of the present study was to evaluate the efficacy of a selective COX-2 inhibitor to prevent the progression of PanINs in a conditional Kras(G12D) mouse model. Offspring of LSL-KRAS(G12D) x PDX-1-Cre intercrosses were randomly allocated to a diet supplemented with the selective COX-2 inhibitor nimesulide (400 ppm) or a control diet. After 10 months, animals were sacrificed. Successful recombination in the pancreas was evaluated by PCR. The pancreas of KRAS(G12D);PDX-1-Cre mice was analyzed for the presence of murine PanINs. Animals fed the COX-2 inhibitor had significantly fewer PanIN-2 and PanIN-3 lesions than control animals (P < 0.05). Ten percent of all pancreatic ducts in the nimesulide-fed animals showed PanIN-2 or PanIN-3 lesions, whereas 40% of the pancreatic ducts in the control animals had PanIN-2 or PanIN-3 lesions. Intrapancreatic prostaglandin E(2) levels were reduced in nimesulide-fed animals. Immunohistochemistry confirmed COX-2 expression in early and late PanINs. In summary, we found that the selective COX-2 inhibitor nimesulide delays the progression of pancreatic cancer precursor lesions in a preclinical animal model. These data highlight the importance of COX-2 in the development of pancreatic cancer. Inhibition of COX-2 may represent an intriguing strategy to prevent pancreatic cancer in high-risk patients.

Kupffer cell blockade reduces hepatic and systemic cytokine levels and lung injury in hemorrhagic pancreatitis in rats.

Objective:To analyze the potential role of the Notch signaling pathway in pancreatic cancer angiogenesis and invasion. Background:Angiogenesis, pain, and early neuroinvasion are clinical features of pancreatic cancer. Blood vessels and nerves develop together and use common routes through the organism. The Notch pathway (Notch-1/4, Jagged-1/2, Delta-1) appears crucial in this process. The current study analyzed the Notch pathway in pancreatic cancer and characterized its angiogenic and invasive effects. Methods:Five PaCa cell lines were cultured for the in vitro experiments. Real-time quantitative RT-PCR was done to quantify mRNA expression in 31 human PaCa specimens, and immunohistochemistry was used to localize protein expression within tumor specimens. Activation of the Notch signaling was done by transfection of PaCa cells with a constitutive active Notch-1 mutant (Notch-IC). Overexpression of Jagged and Delta was achieved by transfection of full-length cDNA. Spheroid assays were used to study angiogenesis and ELISAs to measure VEGF, bFGF, and angiogenin expression. Matrigel invasion assays were used to analyze tumor cell invasion. Results:Notch-3 and Notch-4 mRNA were significantly (P < 0.001) overexpressed in PaCa. Immunohistochemistry revealed protein accumulation of Notch-1 as well. All ligands were significantly up-regulated. A positive immunosignal of ligands was seen in nerves, blood vessels, and ductal tumor cells. Transfection of PaCa cells with the constitutive active Notch-IC mutant and with Jagged-1 revealed increased levels for VEGF. Concomitantly, recombinant Jagged-1 increased sprouting of endothelial cells in the spheroid assay. Conclusion:The Notch pathway most likely regulates neurovascular development in pancreatic cancer. Activation of this signaling pathway by constitutive Notch-1 mutants and by Jagged-1 causes an angiogenic and invasive tumor phenotype. Specific blockade of Notch signaling may therefore be beneficial for patients with pancreatic cancer.

Broad-Spectrum G Protein–Coupled Receptor Antagonist, [D-Arg1,D-Trp5,7,9,Leu11]SP: A Dual Inhibitor of Growth and Angiogenesis in Pancreatic Cancer

Abstract In some cancers cyclooxygenase (COX) inhibition appears to be anti-mitogenic and anti-angiogenic, but the actions of COX-derived prostaglandins in pancreatic cancer (PaCa) are unknown. In this study COX-2 was detected in three of six PaCa cell lines while COX-1 was identified in all cell lines. COX-2 expression correlated with basal and arachidonic acid (AA) stimulated PGE2 production. PGE2 production was inhibited by the COX-2 inhibitor nimesulide. In COX-2 expressing cells, exogenous AA and PGE2 increased VEGF synthesis via the EP2 receptor. Whereas PGE2 stimulated intracellular cAMP formation in COX-2 positive and negative cells, 8-bromo cAMP stimulated VEGF production only in COX-2 expressing cells. Stimulating COX-2 expressing PaCa cell lines with AA enhanced migration of endothelial cells, an effect which was inhibited by a COX-2 inhibitor and EP2 receptor antagonist. These data identify a subset of human PaCa cell lines that express functional COX-2 enzyme. PGE2 generated by specific COX-2 activity increases VEGF secretion in human PaCa cells through an autocrine mechanism.