F. Buccoliero

Thiazolidinediones Inhibit Hepatocarcinogenesis in Hepatitis B Virus―Transgenic Mice by Peroxisome Proliferator-Activated Receptor γ―Independent Regulation of Nucleophosmin

Antidiabetic thiazolidinediones (TZD) have in vitro antiproliferative effect in epithelial cancers, including hepatocellular carcinoma (HCC). The effective anticancer properties and the underlying molecular mechanisms of these drugs in vivo remain unclear. In addition, the primary biological target of TZD, the ligand‐dependent transcription factor peroxisome proliferator‐activated receptor γ (PPARγ), is up‐regulated in HCC and seems to provide tumor‐promoting responses. The aim of our study was to evaluate whether chronic administration of TZD may affect hepatic carcinogenesis in vivo in relation to PPARγ expression and activity. The effect of TZD oral administration for 26 weeks was tested on tumor formation in PPARγ‐expressing and PPARγ‐deficient mouse models of hepatic carcinogenesis. Proteomic analysis was performed in freshly isolated hepatocytes by differential in gel electrophoresis and mass spectrometry analysis. Identified TZD targets were confirmed in cultured PPARγ‐deficient hepatocytes. TZD administration in hepatitis B virus (HBV)–transgenic mice (TgN[Alb1HBV]44Bri) reduced tumor incidence in the liver, inhibiting hepatocyte proliferation and increasing apoptosis. PPARγ deletion in hepatocytes of HBV‐transgenic mice (Tg[HBV]CreKOγ) did not modify hepatic carcinogenesis but increased the TZD antitumorigenic effect. Proteomic analysis identified nucleophosmin (NPM) as a TZD target in PPARγ‐deficient hepatocytes. TZD inhibited NPM expression at protein and messenger RNA levels and decreased NPM promoter activity. TZD inhibition of NPM was associated with the induction of p53 phosphorylation and p21 expression. Conclusion: These findings suggest that chronic administration of TZD has anticancer activity in the liver via inhibition of NPM expression and indicate that these drugs might be useful for HCC chemoprevention and treatment. HEPATOLOGY 2010

COUP-TFII in pancreatic adenocarcinoma: clinical implication for patient survival and tumor progression.

Despite the accumulating knowledge of alterations in pancreatic cancer molecular pathways, no substantial improvements in the clinical prognosis have been made and this malignancy continues to be a leading cause of cancer death in the Western World. The orphan nuclear receptor COUP‐TFII is a regulator of a wide range of biological processes and it may exert a pro‐oncogenic role in cancer cells; interestingly, indirect evidences suggest that the receptor could be involved in pancreatic cancer. The aim of this study was to evaluate the expression of COUP‐TFII in human pancreatic tumors and to unveil its role in the regulation of pancreatic tumor growth. We evaluated COUP‐TFII expression by immunohistochemistry on primary samples. We analyzed the effect of the nuclear receptor silencing in human pancreatic cancer cells by means of shRNA expressing cell lines. We finally confirmed the in vitro results by in vivo experiments on nude mice. COUP‐TFII is expressed in 69% of tested primary samples and correlates with the N1 and M1 status and clinical stage; Kaplan–Meier and Cox regression analysis show that it may be an independent prognostic factor of worst outcome. In vitro silencing of COUP‐TFII reduces the cell growth and invasiveness and it strongly inhibits angiogenesis, an effect mediated by the regulation of VEGF‐C. In nude mice, COUP‐TFII silencing reduces tumor growth by 40%. Our results suggest that COUP‐TFII might be an important regulator of the behavior of pancreatic adenocarcinoma, thus representing a possible new target for pancreatic cancer therapy.