To delineate the roles of the lactogens and GH in the control of perinatal and postnatal growth, fat deposition, insulin production, and insulin action, we generated a novel mouse model that combines resistance to all lactogenic hormones with a severe deficiency of pituitary GH. The model was created by breeding PRL receptor (PRLR)-deficient (knockout) males with GH-deficient (little) females. In contrast to mice with isolated GH or PRLR deficiencies, double-mutant (lactogen-resistant and GH-deficient) mice on d 7 of life had growth failure and hypoglycemia. These findings suggest that lactogens and GH act in concert to facilitate weight gain and glucose homeostasis during the perinatal period. Plasma insulin and IGF-I and IGF-II concentrations were decreased in both GH-deficient and double-mutant neonates but were normal in PRLR-deficient mice. Body weights of the double mutants were reduced markedly during the first 3-4 months of age, and adults had striking reductions in femur length, plasma IGF-I and IGF binding protein-3 concentrations, and femoral bone mineral density. By age 6-12 months, however, the double-mutant mice developed obesity, hyperleptinemia, fasting hyperglycemia, relative hypoinsulinemia, insulin resistance, and glucose intolerance; males were affected to a greater degree than females. The combination of perinatal growth failure and late-onset obesity and insulin resistance suggests that the lactogen-resistant/GH-deficient mouse may serve as a model for the development of the metabolic syndrome.

Background Alcohol is a significant risk factor for development of hepatocellular carcinoma (HCC). To date, no rodent model has demonstrated formation of hepatic neoplasia in the setting of chronic alcohol consumption alone. Methods We investigated whether rats selectively bred for high alcohol preference (P rats), allowed free access to water, or water and 10% (v/v) alcohol for 6, 12 or 18 months, develop hepatic neoplasia. Results At necropsy, liver tumor incidence and multiplicity were significantly increased in 18-month alcohol-consuming versus water-consuming P rats. These data were confirmed histologically by glutathione-S-transferase pi-class (GSTp) staining. Phosphorylated mitogen-activated protein kinase/extracellular signal-regulated kinase 1/2 (MAPK/ERK) staining was also increased in the sinusoidal lining cells within livers of alcohol-consuming versus water only P rats. In addition, cytochrome p450IIE1 (CYP2E1) mRNA, protein expression/activity, and intrahepatic oxidative stress were significantly increased in alcohol-consuming P rat livers versus water only. In contrast, acetaldehyde dehydrogenase expression decreased in alcohol-consuming versus water only P rats. No significant difference in alcohol dehydrogenase expression was detected. Conclusions These data demonstrate that chronic alcohol consumption is associated with hepatic neoplasia, MAPK/ERK activation, increased CYP2E1 activity, and intrahepatic oxidative stress in P rats. Since these rats are well-characterized as a model of alcoholism, these findings identify a novel rodent model of alcohol or “alcoholism”-induced liver neoplasia.

The extracellular signal-regulated (ERK), mitogen-activated protein kinase (p42/p44 MAPK) pathway is up-regulated in hepatocellular carcinoma (HCC). Molecular targeting of this critical mitogenic pathway may have therapeutic potential for the treatment of HCC; however, chemoresistance to long-term therapy may develop. In the present study, we employed smallmolecule MAPK kinase (MEK) inhibitors, including U0126 [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophynyltio)butadiene] and PD184161 (Neoplasia 8:1-8, 2006), in HepG2 and Hep3B human HCC cell lines to identify potential mechanism(s) of resistance. U0126 dose-dependently suppressed ERK phosphorylation at both 1-and 24-h time points in HepG2 cells, previously shown to be sensitive to growth inhibition by U0126. In contrast, ERK phosphorylation was only decreased at the 1-h time point but not at 24 h in the more resistant Hep3B cells. It is interesting that the lack of prolonged phospho-ERK suppression was associated with MEK hyperphosphorylation in Hep3B cells. Several MEK/ERK pathway intermediates were up-regulated in Hep3B cells; furthermore, transfection of Raf-1 small interfering RNA to suppress MEK/ERK pathway activation sensitized Hep3B cells to U0126. MEK inhibitor resistance was independent of p53 or hepatitis Bx protein status. Finally, we showed that combining two chemically distinct MEK inhibitors enhanced growth inhibition and apoptosis compared with the single agents. Taken together, these results suggest that upregulated expression or activity of the MEK/ERK pathway contributes to MEK inhibitor resistance in HCC cells. Our findings also provide preclinical evidence suggesting that the status of the MEK/ERK pathway in patients may predict response to MEK/ERK-targeted therapeutics.

Current management of intraductal papillary mucinous neoplasm (IPMN) according to recently published International Consensus Guidelines depends upon distinguishing it from mucinous cystic neoplasms (MCNs). We have previously shown that prostaglandin E(2) (PGE(2)) is increased in pancreatic cancer tissue over normal controls. Thus, we hypothesized that PGE(2) level in pancreatic fluid differentiates IPMN and MCN and is a biomarker of IPMN dysplasia. Pancreatic fluid was collected in 65 patients at the time of endoscopy (EUS or ERCP) or operation (OR) and analyzed by PGE(2) enzyme-linked immunosorbent assay (ELISA). PGE(2) level was correlated with surgical pathologic diagnosis and dysplastic stage. Mean PGE(2) level (pg/microl) in IPMNs (2.2 +/- 0.6) was greater than in MCNs (0.2 +/- 0.1) (p < 0.05). Mean PGE(2) level of IPMN by dysplastic stage was 0.1 +/- 0.01 (low grade), 1.2 +/- 0.6 (medium grade), 4.4 +/- 0.9 (high grade), and 5.0 +/- 2.3 (invasive). Among invasive IPMN, PGE(2) level dropped in advanced cases with pancreatic ductal obstruction by tumor (0.3 +/- 0) vs non-obstructed (8.6 +/- 2.9). PGE(2) level may help in distinguishing IPMN from MCN in patients with known mucinous lesions. PGE(2) level may also be an indicator of malignant progression of IPMN before ductal obstruction by tumor. Prospective evaluation will be necessary to evaluate the clinical role of PGE(2) level in pancreatic fluid.

1218-1225.)H epatocellular carcinoma is the most common primary liver malignancy worldwide, and its incidence has been rising over the last 20 years. 1 Surgical resection or liver transplantation is the best hope for improving survival in patients with HCC; however, only a minority of patients are candidates for these procedures. 2 Surgical resection for cure is limited to those patients without distant metastases or local invasion of adjacent tissues. 3 Most patients are diagnosed with HCC at stages too advanced for curative therapy, with poor prognosis even with disease spread only to regional lymph nodes. 4 In selected patients, however, surgical resection and transplantation can achieve 5-year survival rates of approximately 60%. 5

Background Chronic ethanol intake is a significant risk factor for the development of cirrhosis and hepatocellular carcinoma (HCC). The effects of ethanol on extracellular signal-regulated kinase (ERK) activation, transforming growth factor alpha (TGF-α) and HCC growth were examined in this study. Methods HepG2, SKHep, Hep3B human HCC cells or normal human hepatocytes were treated with ethanol (0-100mM), exogenous TGF-α, TGF-α neutralization antibody or the MEK inhibitor U0126. TGF-α levels were quantified by ELISA. Growth was determined by trypan blue-excluded cell counts. Cell cycle phase distribution was determined by flow cytometry. Protein expression was determined by Western blot. Results Ethanol treatment (10-40mM) increased ERK activation in HepG2 and SKHep HCC cells but not in Hep3B or human hepatocyte cells. Growth increased in HepG2 (174 ± 29 %, P<0.05) and SKHep (149 ± 12 %, P<0.05) cells in response to ethanol treatment. Correspondingly, ethanol increased S phase distribution in these cells. U0126 suppressed ethanol-induced growth increases. Ethanol treatment for 24 hours also raised TGF-α levels in HepG2 cells (118-198 %) and SKHep cells (112-177 %). Exogenous administration of recombinant TGF-α mimicked the ethanol-induced growth in HepG2 and SKHep cells; TGF-α neutralization antibody effectively abrogated this effect. The TGF-a neutralization antibody also prevented ERK activation by ethanol in HepG2 cells. Conclusion These data demonstrate that clinically relevant doses of ethanol stimulate ERK-dependent proliferation of HCC cells. Ethanol up-regulates TGF-α levels in HCC cells and enhances growth through cell cycles changes, which appear to be mediated through TGF-α-MEK-ERK signaling. Ethanol-MEK signaling in normal hepatocytes is absent, suggesting that ethanol promotion of HCC growth may in part depend upon the acquisition of cancer-specific signaling by hepatocytes.

Hepatocellular carcinoma (HCC) causes 600,000 mortalities per year worldwide. Previous studies from our lab provide evidence for altered mitogen-activated protein kinase and extracellular signal-regulated kinase kinase (MEK) signaling in HCC pathogenesis. We hypothesized that pharmacologic targeting of MEK may prevent HCC. Transforming growth factor-alpha-transgenic mice (CD1-MT42) exposed to diethylnitrosamine were randomized to 20 (trial I) or 35 (trial II) weeks of MEK inhibitor PD0325901 (1, 10 mg/kg) or control via orogastric gavage. Ten HCC (44%) formed in trial I controls versus 0 in treatment arms (p<0.05). Fourteen HCC (50%) formed in trial II controls versus 1 (9%) in treatment arms (p<0.05). Mean HCC volume was 578 mm3 in control versus 46 mm3 in the single tumor formed in trial II. In trial I, foci of altered hepatocytes (FAH) formed in 78% of control versus 40% and 0% (1 and 10 mg/kg PD0325901) in treatment arms (p<0.05). In trial II, incidence of FAH was 80% in control versus 20% and 50% (1 and 10 mg/kg PD0325901) in treatment arms (p<0.05). Hepatocyte expression of phosphorylated extracellular signal-regulated kinase dose-dependently decreased in trial I but remained the same in trial II. Control and treated HCC demonstrated similar proliferation rates, but apoptosis appeared increased with treatment. MEK targeting is effective HCC chemoprevention, perhaps by lowering the apoptotic threshold.

AIM: Clinicopathologic factors predicting overall survival (OS) would help identify a subset to benefit from adjuvant therapy. METHODS:One hundred and sixty-nine patients patients from 1984 to 2009 with curative resections for pancreatic adenocarcinoma were included. Tumors were staged by American Joint Committee on Cancer 7th edition criteria. Univariate and multivariable analyses were performed using Kaplan-Meier methodology or Cox proportional hazard models. Log-rank tests were performed. Statistical inferences were assessed by two-sided 5% significance level. RESULTS:Median age was 67.1 (57.2-73.0) years with equal gender distribution. Tumors were in the head (89.3%) or body/tail (10.7%). On univariate analysis, adjuvant therapy, lymph node (LN) ratio, histologic grade, negative margin status, absence of peripancreatic extension, and T stage were associated with improved OS. Adjuvant therapy, LN ratio, histologic grade, number of nodes examined, negative LN status, and absence of peripancreatic extension were associated with improved recurrence-free survival (RFS). On multivariable analysis, LN ratio and carbohydrate antigen (CA) 19-9 levels were associated with OS. LN ratio was associated with RFS. CONCLUSION:The LN ratio and CA 19-9 levels are independent prognostic factors following curative resections of pancreatic cancer.