Liliana Giménez

Multiplexed methylation profiles of tumor suppressor genes and clinical outcome in lung cancer.

BackgroundChanges in DNA methylation of crucial cancer genes including tumor suppressors can occur early in carcinogenesis, being potentially important early indicators of cancer. The objective of this study was to examine a multiplexed approach to assess the methylation of tumor suppressor genes as tumor stratification and clinical outcome prognostic biomarkers for lung cancer.MethodsA multicandidate probe panel interrogated DNA for aberrant methylation status in 18 tumor suppressor genes in lung cancer using a methylation-specific multiplex ligation-dependent probe amplification assay (MS-MLPA). Lung cancer cell lines (n = 7), and primary lung tumors (n = 54) were examined using MS-MLPA.ResultsGenes frequently methylated in lung cancer cell lines including SCGB3A1, ID4, CCND2 were found among the most commonly methylated in the lung tumors analyzed. HLTF, BNIP3, H2AFX, CACNA1G, TGIF, ID4 and CACNA1A were identified as novel tumor suppressor candidates methylated in lung tumors. The most frequently methylated genes in lung tumors were SCGB3A1 and DLC1 (both 50.0%). Methylation rates for ID4, DCL1, BNIP3, H2AFX, CACNA1G and TIMP3 were significantly different between squamous and adenocarcinomas. Methylation of RUNX3, SCGB3A1, SFRP4, and DLC1 was significantly associated with the extent of the disease when comparing localized versus metastatic tumors. Moreover, methylation of HTLF, SFRP5 and TIMP3 were significantly associated with overall survival.ConclusionsMS-MLPA can be used for classification of certain types of lung tumors and clinical outcome prediction. This latter is clinically relevant by offering an adjunct strategy for the clinical management of lung cancer patients.

Inducible Nitric Oxide Synthase and PPARγ are Involved in Bladder Cancer Progression

PURPOSE We evaluated the role of inducible nitric oxide synthase and PPARγ as prognostic factors for bladder cancer. MATERIALS AND METHODS Inducible nitric oxide synthase and PPARγ were evaluated by Western blot and immunohistochemistry in a mouse bladder cancer model of nonmuscle invasive and invasive MB49-I tumor cells, and in human bladder cancer samples. RESULTS Inducible nitric oxide synthase expression was negative in mouse normal urothelium and higher in invasive than in noninvasive MB49 tumors. In vitro inducible nitric oxide synthase activity, determined as nitrite, was higher in MB49-I than in MB49 cells (p <0.001). In human samples expression was also associated with tumor invasion. Nuclear PPARγ expression was negative in normal mouse urothelium but higher in nonmuscle invasive MB49 than in MB49-I tumors. Similarly in human tumors low PPARγ was associated with poor prognosis factors, such as high histological grade (p = 0.0160) and invasion status (p = 0.0352). A positive correlation was noted between inducible nitric oxide synthase and PPARγ in low histological grade and nonmuscle invasive tumors (Pearson correlation index 0.6368, p = 0.0351, 0.4438 and 0.0168, respectively). As determined by gene reporter assay, PPARγ activity was induced by nitric oxide only in nonmuscle invasive MB49 cells (p <0.001). CONCLUSIONS Results suggest that increased PPARγ controls inducible nitric oxide synthase expression at early tumor stages. However, regulation is lost at advanced tumor stages, when the increase in inducible nitric oxide synthase and the decrease in PPARγ seem to be associated with bladder cancer progression.