Leda Guzmán

Analysis of aberrant methylation on promoter sequences of tumor suppressor genes and total DNA in sputum samples: a promising tool for early detection of COPD and lung cancer in smokers

BackgroundChronic obstructive pulmonary disease (COPD) is a disorder associated to cigarette smoke and lung cancer (LC). Since epigenetic changes in oncogenes and tumor suppressor genes (TSGs) are clearly important in the development of LC. In this study, we hypothesize that tobacco smokers are susceptible for methylation in the promoter region of TSGs in airway epithelial cells when compared with non-smoker subjects. The purpose of this study was to investigate the usefulness of detection of genes promoter methylation in sputum specimens, as a complementary tool to identify LC biomarkers among smokers with early COPD.MethodsWe determined the amount of DNA in induced sputum from patients with COPD (n = 23), LC (n = 26), as well as in healthy subjects (CTR) (n = 33), using a commercial kit for DNA purification, followed by absorbance measurement at 260 nm. The frequency of CDKN2A, CDH1 and MGMT promoter methylation in the same groups was determined by methylation-specific polymerase chain reaction (MSP). The Fisher’s exact test was employed to compare frequency of results between different groups.ResultsDNA concentration was 7.4 and 5.8 times higher in LC and COPD compared to the (CTR) (p < 0.0001), respectively. Methylation status of CDKN2A and MGMT was significantly higher in COPD and LC patients compared with CTR group (p < 0.0001). Frequency of CDH1 methylation only showed a statistically significant difference between LC patients and CTR group (p < 0.05).ConclusionsWe provide evidence that aberrant methylation of TSGs in samples of induced sputum is a useful tool for early diagnostic of lung diseases (LC and COPD) in smoker subjects.Virtual slidesThe abstract MUST finish with the following text: Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1127865005664160

Loss of Expression of Reprimo, a p53-induced Cell Cycle Arrest Gene, Correlates with Invasive Stage of Tumor Progression and p73 Expression in Gastric Cancer.

Reprimo (RPRM), a downstream effector of p53-induced cell cycle arrest at G2/M, has been proposed as a putative tumor suppressor gene (TSG) and as a potential biomarker for non-invasive detection of gastric cancer (GC). The aim of this study was to evaluate the epigenetic silencing of RPRM gene by promoter methylation and its tumor suppressor function in GC cell lines. Furthermore, clinical significance of RPRM protein product and its association with p53/p73 tumor suppressor protein family was explored. Epigenetic silencing of RPRM gene by promoter methylation was evaluated in four GC cell lines. Protein expression of RPRM was evaluated in 20 tumor and non-tumor matched cases. The clinical significance of RPRM association with p53/p73 tumor suppressor protein family was assessed in 114 GC cases. Tumor suppressor function was examined through functional assays. RPRM gene expression was negatively correlated with promoter methylation (Spearman rank r = -1; p = 0.042). RPRM overexpression inhibited colony formation and anchorage-independent growth. In clinical samples, RPRM gene protein expression was detected in 75% (15/20) of non-tumor adjacent mucosa, but only in 25% (5/20) of gastric tumor tissues (p = 0.001). Clinicopathological correlations of loss of RPRM expression were significantly associated with invasive stage of GC (stage I to II-IV, p = 0.02) and a positive association between RPRM and p73 gene protein product expression was found (p<0.0001 and kappa value = 0.363). In conclusion, epigenetic silencing of RPRM gene by promoter methylation is associated with loss of RPRM expression. Functional assays suggest that RPRM behaves as a TSG. Loss of expression of RPRM gene protein product is associated with the invasive stage of GC. Positive association between RPRM and p73 expression suggest that other members of the p53 gene family may participate in the regulation of RPRM expression.

New 1H-Benzo[f]indazole-4,9-diones Conjugated with C-Protected Amino Acids and Other Derivatives: Synthesis and in Vitro Antiproliferative Evaluation.

1H-Benzo[f]indazole-4,9-dione derivatives conjugated with C-protected amino acids (glycine, l-alanine, l-phenylalanine and l-glutamic acid) 6a–l were prepared by chemically modifying the prenyl substituent of 3-methyl-7-(4-methylpent-3-enyl)-1H-benzo[f]indazole-4,9-dione 2 through epoxidation, degradative oxidation, oxidation and N-acyl condensation reactions. The chemical structures of the synthesized compounds were elucidated by analyzing their IR, 1H-NMR and 13C-NMR spectral data together with elemental analysis for carbon, hydrogen and nitrogen. The preliminary in vitro antiproliferative activity of the synthesized derivatives was evaluated on KATO-III and MCF-7 cell lines using a cell proliferation assay. The majority of the derivatives exhibited significant antiproliferative activity with IC50 values ranging from 25.5 to 432.5 μM. These results suggest that 1H-benzo[f]indazole-4,9-dione derivatives are promising molecules to be researched for developing new anticancer agents.