Project description:The clinical management of prostate cancer is challenging and currently relies primarily on staging, histological grading, and tumor size. In this study, we take advantage of the propensity of prostate cancer to be multifocal and categorize aggressiveness of individual prostate cancer foci based on DNA methylation patterns in primary and metastatic tumors.
Project description:Genome wide DNA methylation profiling of normal and tumor prostate samples, as well as cultured primary prostate cells overexpressing DNA Methyltransferases (DNMTs) and EZH2 Candidate gene based studies have identified a handful of aberrant CpG DNA methylation events in prostate cancer. However, DNA methylation profiles have not been compared on a large scale between prostate tumor and normal prostate, and the mechanisms behind these alterations are unknown. In this study, we quantitatively profiled 95 primary prostate tumors and 86 healthy prostate tissue samples for their DNA methylation levels at 26,333 CpGs representing 14,104 gene promoters by using the Illumina HumanMethylation27 platform. A 2-class Significance Analysis of this dataset revealed 5,912 CpG sites with increased DNA methylation and 2,151 CpG sites with decreased DNA methylation in tumors (FDR < 0.8%). Prediction Analysis of this dataset identified 87 CpGs that are the most predictive diagnostic methylation biomarkers of prostate cancer. By integrating available clinical follow-up data, we also identified 69 prognostic DNA methylation alterations that correlate with biochemical recurrence of the tumor. To identify the mechanisms responsible for these genome-wide DNA methylation alterations, we measured the gene expression levels of several DNA methyltransferases (DNMTs) and their interacting proteins by TaqMan qPCR and observed increased expression of DNMT3A2, DNMT3B, and EZH2 in tumors. Subsequent transient transfection assays in cultured primary prostate cells revealed that DNMT3B1 and DNMT3B2 overexpression resulted in increased methylation of a substantial subset of CpG sites that also showed tumor-specific increased methylation. Bisulfite converted DNA from 193 samples were hybridized to the Illumina Infinium 27k Human Methylation Beadchip v1.2. The tissue samples (first 181) and the cultured cell samples (last 12) were normalized independently.
Project description:Genome wide DNA methylation profiling of normal and tumor prostate samples, as well as cultured primary prostate cells overexpressing DNA Methyltransferases (DNMTs) and EZH2 Candidate gene based studies have identified a handful of aberrant CpG DNA methylation events in prostate cancer. However, DNA methylation profiles have not been compared on a large scale between prostate tumor and normal prostate, and the mechanisms behind these alterations are unknown. In this study, we quantitatively profiled 95 primary prostate tumors and 86 healthy prostate tissue samples for their DNA methylation levels at 26,333 CpGs representing 14,104 gene promoters by using the Illumina HumanMethylation27 platform. A 2-class Significance Analysis of this dataset revealed 5,912 CpG sites with increased DNA methylation and 2,151 CpG sites with decreased DNA methylation in tumors (FDR < 0.8%). Prediction Analysis of this dataset identified 87 CpGs that are the most predictive diagnostic methylation biomarkers of prostate cancer. By integrating available clinical follow-up data, we also identified 69 prognostic DNA methylation alterations that correlate with biochemical recurrence of the tumor. To identify the mechanisms responsible for these genome-wide DNA methylation alterations, we measured the gene expression levels of several DNA methyltransferases (DNMTs) and their interacting proteins by TaqMan qPCR and observed increased expression of DNMT3A2, DNMT3B, and EZH2 in tumors. Subsequent transient transfection assays in cultured primary prostate cells revealed that DNMT3B1 and DNMT3B2 overexpression resulted in increased methylation of a substantial subset of CpG sites that also showed tumor-specific increased methylation.
Project description:Prostate cancer is the second most occurring cancer in men worldwide, and with the advances made with screening for prostate-specific antigen, it has been prone to early diagnosis and over-treatment. To better understand the mechanisms of tumorigenesis and possible treatment responses, we developed a mathematical model of prostate cancer which considers the major signalling pathways known to be deregulated. The model includes pathways such as androgen receptor, MAPK, Wnt, NFkB, PI3K/AKT, MAPK, mTOR, SHH, the cell cycle, the epithelial-mesenchymal transition (EMT), apoptosis and DNA damage pathways. The final model accounts for 133 nodes and 449 edges. We applied a methodology to personalise this Boolean model to molecular data to reflect the heterogeneity and specific response to perturbations of cancer patients, using TCGA and GDSC datasets.
Project description:A major challenge in the clinical management of prostate cancer is the inability to definitively diagnose indolent versus aggressive cases. Contributing to this challenge is a lack of basic science understanding of the molecular basis behind aggressiveness subtypes in prostate cancer. DNA methylation is the epigenetic addition of a methyl group to the DNA base cytosine and has been found to regulate cell proliferation and environmental adaptation. We hypothesized that DNA methylation changes are a mechanism by which an aggressive cancer attains phenotypes that distinguish it from indolent cases via disruption of regulatory networks. This hypothesis was tested by comparing DNA methylation between benign prostate and both low grade (Gleason score 6) and high grade (Gleason score 8 to 10) groups. Methylome-wide next generation sequencing was performed on formalin-fixed paraffin embedded (FFPE) samples from radical prostatectomy cases using MBD-isolated genome sequencing (MiGS). This technique uses a DNA methylation binding protein (MBD) to purify fragments from a genomic library with a high level of CpG DNA methylation. These fragments were then sequenced via next generation sequencing, the reads were aligned to a reference genome, and then the reads were counted within non-overlapping 50bp windows genome wide. Statistical analysis was then performed on these windowed counts to produce differentially methylated regions (DMRs). MBD-isolated Genome Sequencing (MiGS) for groups of benign prostate (from cystoprostatectomy), low grade prostate cancer (from radical prostatectomy with Gleason Score 6), and high grade prostate cancer (from radical prostatectomy with Gleason Scores 8 to 10) in both European Americans and African Americans
Project description:Great efforts have been made to identify key molecular aberrations that sustain growth and confer resistance to androgen deprivation therapy (ADT) in advanced prostate cancer (PC), and yet PC remains a lethal disease. Recent years have witnessed the discovery of several master regulator transcription factors that enhance lethal PC aggressiveness and provide actionable targets that may improve patient survival. Here we explore the role of the microphthalmia transcription factor (MITF) in lethal prostate cancer. To identify the mechanisms through which MITF mododulates prostate cancer aggressiveness, we knock-down MITF in three prostate cancer cell lines to identify the MITF regulated effector gene network contributing to lethal prostate cancer. Methods: We compared global transcription of three prostate cancer cell lines transduced with a siRNA control and 2 siRNAs targetting MITF by RNAseq. Results: RNA-seq of MITF knockdown prostate cancer cells uncovered a trasncriptional network of MITF regulated genes Conclusions: MITF regulates a discrette gene network that contributes to prostate cancer aggressiveness
Project description:We aimed to investigate the transcriptional program associated with pimonidazole staining in prostate cancer. A pimonidazole gene signature was identified that showed positive correlation to Ki67 labeling index, indicating increased proliferation in pimonidazole positive tumors. A positive correlation to clinical tumor stage and presence of lymph node metastasis was also found, consistent with associations between pimonidazole staining and clinico-pathological parameters. Moreover, the gene signature was associated with high Gleason score in a validation cohort of 59 patients and showed prognostic impact independent of Gleason score and other clinical markers in a watchful waiting validation cohort of 281 patients. Our work reveals the molecular basis of an aggressive prostate cancer phenotype reflected by pimonidazole staining, and suggests that genes involved in proliferation, DNA repair and hypoxia response contribute to this phenotype. We combined pimonidazole immunohistochemistry data and expression profiles to identify transcriptional program activated in pimonidazole positive tumors. Whole-genome gene expression profiles were determined in tumor biopsies from an investigation cohort of 46 patients, where 39 patients had received pimonidazole prior to surgery. Gene ontology analysis of 1046 genes upregulated in pimonidazole positive tumors, as defined by a staining fraction above 10%, showed significant enrichment of the biologic processes cell cycle, translation and cellular response to stress. Gene set analysis based on this result identified gene expressions in proliferation, DNA repair and hypoxia response as major parts of the transcriptional program associated with pimonidazole staining. Gene expression data of four prostate cancer cell lines were used to generate hypoxia response gene sets for this analysis. A signature of the 32 most essential genes in the program was constructed and shown to be associated with prostate cancer aggressiveness in two independent validation cohorts.
Project description:To identify molecular effects of genistein on DNA methylation in prostate cancer, we compared DNA methylation profiles of genistein-treated tumors with placebo-treated samples. There were 156 probes with significantly increased methylation in placebo-treated cases versus normal tissues that were not significant between genistein-treated cases and normal tissues, suggesting that genistein may have had some demethylation effects. These 156 probes corresponded to at least 92 separate genes including ADCY4, ALOX12, HAAO, LRRC4, NEU1, RAPGEFL1, and WNT7B.These findings highlight the effects of genistein on global changes in DNA methylation in prostate cancer and its effects on molecular pathways involved in prostate tumorigenesis.
Project description:Prostate cancer is the Prostate cancer is the most prevalent cancer in men. However, the majority of prostate cancers diagnosed today are indolent with 14% of patients diagnosed with lethal prostate cancer. It is of great importance to determine the molecular features that are involved in the aggressiveness of prostate cancers. To this end, we found that through SWATH-MS proteomics analyses of 108 well-preserved frozen prostate tissues of various disease states, tmost prevalent cancer in men. However, the majority of prostate cancers diagnosed today are indolent with 14% of patients diagnosed with lethal prostate cancer. It is of great importance to determine the molecular features that are involved in the aggressiveness of prostate cancers. To this end, we deployed SWATH-MS proteomics analyses of 108 well-preserved frozen prostate tissues of various disease states.
Project description:Prostate cancer incidence and related mortality are disproportionately higher in African American (AA) men than European American (EA) men, but the molecular mechanisms contributing to racial disparities are not fully elucidated. To identify molecular factors that can contribute to disease biology in prostate cancer from AA and EA men, we utilized a multi-omics approach to measure and integrate DNA methylation with gene expression changes. We compared and contrasted results from adjacent non-tumor and tumor tissues from AA and EA men. We found that hypermethylated regions are enriched for PRC2 and H3K27me3 pathways and EZH2/SUZ12 cofactors in a race-independent manner. On the other hand, hypomethylated regions in prostate tumors from AA men were enriched for olfactory/ribosomal pathways as well as distinct cofactors such as CTCF and KMT2A. DNA methylation at transcription start sites and 5’-UTR at GATA3, an androgen receptor (AR) coregulator, is associated with decreased gene expression in prostate tumors of AA men. Our analysis also showed an inverse correlation between DNA methylation and RNA expression of AR transcriptional targets, such as TRIM63, in prostate tumors of AA men. Our observations suggest a dysregulation of the AR signaling pathway in prostate cancer from AA men. To determine whether targeting AR results in race-specific gene expression changes, we utilized a prostate-cancer-specific Boolean network. Our simulation revealed that prolonged AR inhibition results in significant dysregulation in TGF-β, IDH1, and cell cycle pathways in prostate cancer of AA men. We expanded our observation of gene expression changes in the Boolean network and investigated RNA-sequencing data to better understand overall transcriptional alterations occurring in prostate tumors from AA and EA men. We found that gene expression changes related to microtubules, a subset of immune-related, and TMPRSS2-fusion pathways were dysregulated in prostate tumors of AA men and corresponded with progression-free survival of AA men. Altogether, the current study dissects complex signaling networks that are clinically actionable in prostate cancer from AA and EA men.