Epigenetic Regulation of Gfi1 in Endocrine-Related Cancers: a Role Regulating Tumor Growth.

Prostate and breast cancer constitute the most common cancers among men and women worldwide. The aging population is one of the main risk factors for prostate and breast cancer development and accumulating studies link aging with epigenetic changes. Growth factor independence-1 (Gfi1) is a transcriptional repressor with an important role in human malignancies, including leukemia, colorectal carcinoma, and lung cancer, but its role in prostate and breast cancer is unknown. We have found that Gfi1 epigenetic silencing is a common event in prostate and breast cancer. Gfi1 re-expression in prostate and breast cancer cell lines displaying Gfi1 epigenetic silencing decreases cell proliferation, reduced colony formation density, and tumor growth in nude mice xenografts. In addition, we found that Gfi1 repress alpha 1-anti-trypsin (AAT) and alpha 1-anti-chymotrypsin (ACT) expression, two genes with important functions in cancer development, suggesting that Gfi1 silencing promotes tumor growth by increasing AAT and ACT expression in our system. Finally, Gfi1 epigenetic silencing could be a promising biomarker for prostate cancer progression because it is associated with shorter disease-free survival. In conclusion, our findings strongly indicate that Gfi1 epigenetic silencing in prostate and breast cancer could be a crucial step in the development of these two-well characterized endocrine related tumors.

Epigenetics in Schizophrenia: A Pilot Study of Global DNA Methylation in Different Brain Regions Associated with Higher Cognitive Functions.

Attempts to discover genes that are involved in the pathogenesis of major psychiatric disorders have been frustrating and often fruitless. Concern is building about the need to understand the complex ways in which nature and nurture interact to produce mental illness. We analyze the epigenome in several brain regions from schizophrenic patients with severe cognitive impairment using high-resolution (450K) DNA methylation array. We identified 139 differentially methylated CpG sites included in known and novel candidate genes sequences as well as in and intergenic sequences which functions remain unknown. We found that altered DNA methylation is not restricted to a particular region, but includes others such as CpG shelves and gene bodies, indicating the presence of different DNA methylation signatures depending on the brain area analyzed. Our findings suggest that epimutations are not relatables between different tissues or even between tissues' regions, highlighting the need to adequately study brain samples to obtain reliable data concerning the epigenetics of schizophrenia.

Development of Castration Resistant Prostate Cancer can be Predicted by a DNA Hypermethylation Profile.

PURPOSE: Detection of DNA hypermethylation has emerged as a novel molecular biomarker for prostate cancer diagnosis and evaluation of prognosis. We sought to define whether a hypermethylation profile of patients with prostate cancer on androgen deprivation would predict castrate resistant prostate cancer. MATERIALS AND METHODS: Genome-wide methylation analysis was performed using a methylation cancer panel in 10 normal prostates and 45 tumor samples from patients placed on androgen deprivation who were followed until castrate resistant disease developed. Castrate resistant disease was defined according to EAU (European Association of Urology) guideline criteria. Two pathologists reviewed the Gleason score, Ki-67 index and neuroendocrine differentiation. Hierarchical clustering analysis was performed and relationships with outcome were investigated by Cox regression and log rank analysis. RESULTS: We found 61 genes that were significantly hypermethylated in greater than 20% of tumors analyzed. Three clusters of patients were characterized by a DNA methylation profile, including 1 at risk for earlier castrate resistant disease (log rank p = 0.019) and specific mortality (log rank p = 0.002). Hypermethylation of ETV1 (HR 3.75) and ZNF215 (HR 2.89) predicted disease progression despite androgen deprivation. Hypermethylation of IRAK3 (HR 13.72), ZNF215 (HR 4.81) and SEPT9 (HR 7.64) were independent markers of prognosis. Prostate specific antigen greater than 25 ng/ml, Gleason pattern 5, Ki-67 index greater than 12% and metastasis at diagnosis also predicted a negative response to androgen deprivation. Study limitations included the retrospective design and limited number of cases. CONCLUSIONS: Epigenetic silencing of the mentioned genes could be novel molecular markers for the prognosis of advanced prostate cancer. It might predict castrate resistance during hormone deprivation and, thus, disease specific mortality. Gene hypermethylation is associated with disease progression in patients who receive hormone therapy. It could serve as a marker of the treatment response.

DNA methylation pattern of gene promoters of major neurotransmitter systems in older patients with schizophrenia with severe and mild cognitive impairment.

OBJECTIVE: To analyze, in older patients with schizophrenia, the methylation status of a set of genes associated with the pathophysiology of the disorder but including anatomical, clinical, and cognitive criteria in the experimental design that, in conjunction with the epigenetic status of specific genes, allows us to derive an integrative model. METHOD: This study included 29 human brain samples from older schizophrenic patients with severe and mild cognitive impairment. We administered a comprehensive battery of neurocognitive tests to determine the size of the impairment across different cognitive domains. We focused our study on the analysis of the methylation pattern of 19 genes of major neurotransmitter systems using methylation-specific PCR and bisulfite genomic sequencing. RESULTS: Our results highlight an absence of hypermethylation and hypomethylation in older patients with schizophrenia and in healthy controls, irrespective of the degree of the cognitive deficit measured in the neuropsychological assessment (Fisher's exact test; p<0.05). CONCLUSION: mRNA or protein expression level differences in genes of major neurotransmitter systems that are known to be altered in schizophrenia must be because of regulatory mechanisms other than the DNA methylation of its promoter regions, although our results highlight the idea that the analysis of the epigenetic mechanisms involved in schizophrenia represents a new approach that has the possibility of uncovering molecular mechanisms of dysregulated gene expression in this complex disorder.

A DNA hypermethylation profile reveals new potential biomarkers for prostate cancer diagnosis and prognosis.

BACKGROUND: DNA hypermethylation has emerged as a novel molecular biomarker for the evaluation of prostate cancer diagnosis and prognosis. Defining the specific gene hypermethylation profile for prostate cancer could involve groups of genes that specifically discriminate patients with indolent and aggressive tumors. METHODS: Genome-wide methylation analysis was performed on 83 tumor and 10 normal prostate samples using the GoldenGate Methylation Cancer Panel I (Illumina, Inc.). All clinical stages of disease were considered. RESULTS: We found 41 genes hypermethylated in more than 20% of the tumors analyzed (P < 0.01). Of these, we newly identified GSTM2 and PENK as being genes that are hypermethylated in prostate cancer and that were simultaneously methylated in 40.9% of the tumors analyzed. We also identified panels of genes that are more frequently methylated in tumor samples with clinico-pathological indicators of poor prognosis: a high Gleason score, elevated Ki-67, and advanced disease. Of these, we found simultaneous hypermethylation of CFTR and HTR1B to be common in patients with a high Gleason score and high Ki-67 levels; this might indicate the population at higher risk of therapeutic failure. The DNA hypermethylation profile was associated with cancer-specific mortality (log-rank test, P = 0.007) and biochemical recurrence-free survival (log-rank test, P = 0.0008). CONCLUSIONS: Our findings strongly indicate that epigenetic silencing of GSTM2 and PENK is a common event in prostate cancer that could be used as a molecular marker for prostate cancer diagnosis. In addition, simultaneous HTR1B and CFTR hypermethylation could help discriminate aggressive from indolent prostate tumors.

DNA methylation, histone modifications, and signal transduction pathways: a close relationship in malignant gliomas pathophysiology.

Gliomas are the most common type of primary brain tumor. Although tremendous progress has been achieved in the recent years in the diagnosis and treatment, its molecular etiology remains unknown. In this regard, epigenetics represents a new approach to study the mechanisms that control gene expression and function without changing the sequence of the genome. In the present paper we describe the main findings about the alterations of cell signaling pathways in the most aggressive glioma in the adult population, namely, glioblastoma, in which epigenetic mechanisms and the emerging role of cancer stem cell play a crucial function in the development of new biomarkers for its detection and prognosis and the corresponding development of new pharmacological strategies.