Purpose: The RAS-association domain family 1, isoform A (RASSF1A) gene is shown to be inactivated in prostate cancers. However, the molecular mechanism of silencing of the RASSFIA gene is not fully understood. The present study was designed to investigate the mechanisms of inactivation of the RASSF1A gene through the analysis of CpG methylation and histone acetylation and H3 methylation associated with the RASSF1A promoter region.
Experimental Design: Methylation status of the RASSF1A gene was analyzed in 131 samples of prostate cancer, 65 samples of benign prostate hypertrophy (BPH), and human prostate cell lines using methylation-specific PCR. Histone acetylation (acetyl-H3, acetyl-H4) and H3 methylation (dimethyl-H3-K4, dimethyl-H3-K9) status associated with the promoter region in prostate cells were analyzed by chromatin immunoprecipitation (ChIP) assay.
Results: Aberrant methylation was detected in 97 (74.0%) prostate cancer samples and 12 (18.5%) BPH samples. The methylation frequency of RASSF1A showed a significant increase with high Gleason sum and high stage. The ChIP assays showed enhancement of histone acetylation and dimethyl-H3-K4 methylation on the unmethylated RASSF1A promoter. TSA alone was unable to alter key components of the histone code. However, after 5-aza-2'-deoxy-cytidine treatment, there was a complete reversal of the histone components in the hypermethylated promoter. Levels of acetyl-H3, acetyl-H4, and dimethyl-H3-K4 became more enriched, whereas H3K9me2 levels were severely depleted.
Conclusions: This is the first report suggesting that reduced histone acetylation or H3K4me2 methylation and increased dimethyl-H3-K9 methylation play a critical role in the maintenance of promoter DNA methylation-associated RASSF1A gene silencing in prostate cancer.
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http://dx.doi.org/10.1158/1078-0432.CCR-06-2225 | DOI Listing |
Kidney Int
December 2024
Clinic of Internal Medicine I, Hematology, Oncology and Stem Cell Transplantation, Medical Centre - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Comprehensive Cancer Center Freiburg (CCCF), Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; German Cancer Consortium (DKTK), Partner Site, Freiburg; Signalling Research Centres BIOSS and CIBSS, Faculty of Biology University of Freiburg, Freiburg, Germany. Electronic address:
RASSF1A is frequently biallelically inactivated in clear cell renal cell carcinoma (ccRCC) due to loss of chromosome 3p and promoter hypermethylation. Here we investigated the cellular and molecular consequences of single and combined deletion of the Rassf1a and Vhl tumor suppressor genes to model the common ccRCC genotype of combined loss of function of RASSF1A and VHL. In mouse embryonic fibroblasts and in primary kidney epithelial cells, double deletion of Rassf1a and Vhl caused chromosomal segregation defects and increased formation of micronuclei, demonstrating that pVHL and RASSF1A function to maintain genomic integrity.
View Article and Find Full Text PDFCaspian J Intern Med
October 2024
Student Research Committee, Faculty of Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.
Background: It is believed that anthracosis is one of the most important occupational diseases, mainly seen in the residents of industrial areas and coal mine workers. This bronchial disease is more common in Asia's rural areas, particularly in the Middle East. In this study, we examined the epidemiology and genetic factors affecting this disease and its relationship with different types of cancer.
View Article and Find Full Text PDFEndocrine
November 2024
Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy.
Diagnostics (Basel)
November 2024
Consorzio Sannio Tech, 82030 Apollosa, Italy.
Cancers (Basel)
October 2024
Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy.
: Non-Small Cell Lung Cancer (NSCLC) remains a challenging disease to manage with effectiveness. Early detection and precise monitoring are crucial for improving patient outcomes. Circulating tumor DNA (ctDNA) offers a non-invasive cancer detection and monitoring method.
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