Treatment of prostate cancer cells with S-adenosylmethionine leads to genome-wide alterations in transcription profiles

The Simultaneous Treatment of PC-3 Cells with the DNA-Demethylating Agent Decitabine and S-Adenosylmethionine Leads to Synergistic Anticancer Effects

Background: Epigenetic dysregulation is a common feature of cancer. Promoter demethylation of tumor-promoting genes and global DNA hypomethylation may trigger tumor progression. Epigenetic changes are unstable; thus, research has focused on detecting remedies that target epigenetic regulators. Previous studies have suggested that concordantly targeting hypomethylation and hypermethylation is beneficial for suppressing both the oncogenic and pro-metastatic functions of cancer cells. Therefore, we aimed to investigate the effect of a combination of S-adenosylmethionine (SAM) and the demethylating agent decitabine on prostate cancer cells. Materials and Methods: Prostate cancer cells (PC-3) were treated with SAM, decitabine, or a combination of both. Proliferation, migration, invasion, and methylation assays were also performed. A transcriptome study was conducted to detect different gene clusters between the treatment groups, followed by analyses using the Kyoto Encyclopedia of Genes and Genomes pathway and ingenuity pathway analysis. Finally, to gain information on differential gene expression, promoter methylation studies were performed. Results: Groups treated with decitabine, SAM, or their combination showed reduced proliferative capacity. The decitabine-treated group showed a marginal increase in cell migration and invasion, whereas the SAM-treated and combination treatment groups showed reduced invasion and migration potential. Methylation assays demonstrated the restoration of decitabine-induced demethylation in prostate cancer samples, whereas the transcriptome study revealed the upregulation of different gene clusters between the treatment groups. Methylation studies confirmed that SAM could restore the decitabine-induced demethylation of proto-oncogenes, but it did not induce the re-methylation of tumor-suppressor genes. Conclusions: Combination treatment with SAM and decitabine had an additive effect and did not nullify each other.

Control of epigenomic landscape and development of fetal male germ cells through L-serine metabolism

Sex-specific metabolic characteristics emerge in the mouse germ line after reaching the genital ridges around embryonic day 10.5, coinciding with sexual differentiation. However, the impact of such metabolic characteristics on germ cell development remains unclear. In this study, we observed the specific upregulation in male fetal germ cells of D-3-phosphoglycerate dehydrogenase (PHGDH), the primary enzyme in the serine-glycine-one-carbon metabolism, along with an increase in a downstream metabolite, S-adenosylmethionine (SAM), crucial for protein and nucleic acid methylation. Inhibiting PHGDH in fetal testes resulted in reduced SAM levels in germ cells, accompanied by increases in the number of mouse vasa homolog (MVH/VASA)-positive germ cells and the promyelocytic leukemia zinc finger (PLZF)-positive undifferentiated spermatogonia ratio. Furthermore, PHGDH inhibition led to a decrease in the methylation of histone H3 and DNA, resulting in aberrations in gene expression profiles. In summary, our findings underscore the significant role of certain metabolic mechanisms in the development of male germ cells.

Abnormal changes in metabolites caused by m6A methylation modification: The leading factors that induce the formation of immunosuppressive tumor microenvironment and their promising potential for clinical application

BACKGROUND

N6-methyladenosine (m6A) RNA methylation modifications have been widely implicated in the metabolic reprogramming of various cell types within the tumor microenvironment (TME) and are essential for meeting the demands of cellular growth and maintaining tissue homeostasis, enabling cells to adapt to the specific conditions of the TME. An increasing number of research studies have focused on the role of m6A modifications in glucose, amino acid and lipid metabolism, revealing their capacity to induce aberrant changes in metabolite levels. These changes may in turn trigger oncogenic signaling pathways, leading to substantial alterations within the TME. Notably, certain metabolites, including lactate, succinate, fumarate, 2-hydroxyglutarate (2-HG), glutamate, glutamine, methionine, S-adenosylmethionine, fatty acids and cholesterol, exhibit pronounced deviations from normal levels. These deviations not only foster tumorigenesis, proliferation and angiogenesis but also give rise to an immunosuppressive TME, thereby facilitating immune evasion by the tumor.

AIM OF REVIEW

The primary objective of this review is to comprehensively discuss the regulatory role of m6A modifications in the aforementioned metabolites and their potential impact on the development of an immunosuppressive TME through metabolic alterations.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review aims to elaborate on the intricate networks governed by the m6A-metabolite-TME axis and underscores its pivotal role in tumor progression. Furthermore, we delve into the potential implications of the m6A-metabolite-TME axis for the development of novel and targeted therapeutic strategies in cancer research.

S-adenosylmethionine treatment affects histone methylation in prostate cancer cells

S-adenosylmethionine (SAM) represents a potent inhibitor of cancer cell proliferation, migration, and invasionin vitro.The underlying mechanisms remain elusive. Here, we examined, if treatment with SAM may cause alterations in the methylation of the histone marks H3K4me3 and H3K27me3, which are both known to play important roles in the initiation and progression of prostate cancer. We treated PC-3 cells with 200 µmol SAM, a concentration known to cause anticancerogenic effects, followed by ChIP-sequencing for H3K4me3 and H3K27me3. We detected 236 differentially methylated regions for H3K27me3 and 560 differentially methylated regions for H3K4me3. GO Term enrichment showed upregulation of anticancerogenic, as well as downregulation of cancerogenic related biological processes, molecular functions, and pathways. Furthermore, we compared specific methylation profiles of SAM treated samples to gene expression changes (RNA-Seq). 35 upregulated and 56 downregulated genes (total: 604 differentially expressed genes) could be related to hypomethylated and hypermethylated regions. 17 upregulated genes could be identified as tumor suppressor genes, 45 downregulated genes in contrast are considered as oncogenes. As a conclusion it can be stated that SAM treatment of prostate cancer cells resulted in alterations of H3K4me3 and H3K27me3 methylation profiles. Gene to peak annotation, alignment with results of a transcriptome study as well as GO-term analysis underpinned the biological relevance of methylation changes.

S-Adenosylmethionine Treatment Diminishes the Proliferation of Castration-Resistant Prostate Cancer Cells by Modulating the Expression of miRNAs

AdoMet (S-adenosylmethionine) inhibits cancer cell proliferation and migration via epigenetic alterations. This study aimed to investigate whether AdoMet may cause alterations in microRNA (miRNA) expression profiles that are important for the initiation and progression of prostate cancer. PC-3 cells were treated with AdoMet before miRNA sequencing. A total of 17 differentially expressed miRNAs were detected. Target gene prediction was performed by means of databases. Results were aligned to transcriptomic data. The bioinformatic analysis revealed upregulation of anticancerogenic genes, downregulation of cancerogenic-related processes and pathways. Knocking down hsa-miR-192-5p in PC-3 cells resulted in downregulation of cancer cell proliferation, thus confirming these results.

Lineage Plasticity and Stemness Phenotypes in Prostate Cancer: Harnessing the Power of Integrated "Omics" Approaches to Explore Measurable Metrics

Prostate cancer (PCa), the most frequent and second most lethal cancer type in men in developed countries, is a highly heterogeneous disease. PCa heterogeneity, therapy resistance, stemness, and lethal progression have been attributed to lineage plasticity, which refers to the ability of neoplastic cells to undergo phenotypic changes under microenvironmental pressures by switching between developmental cell states. What remains to be elucidated is how to identify measurements of lineage plasticity, how to implement them to inform preclinical and clinical research, and, further, how to classify patients and inform therapeutic strategies in the clinic. Recent research has highlighted the crucial role of next-generation sequencing technologies in identifying potential biomarkers associated with lineage plasticity. Here, we review the genomic, transcriptomic, and epigenetic events that have been described in PCa and highlight those with significance for lineage plasticity. We further focus on their relevance in PCa research and their benefits in PCa patient classification. Finally, we explore ways in which bioinformatic analyses can be used to determine lineage plasticity based on large omics analyses and algorithms that can shed light on upstream and downstream events. Most importantly, an integrated multiomics approach may soon allow for the identification of a lineage plasticity signature, which would revolutionize the molecular classification of PCa patients.

Cul4A-DDB1-mediated monoubiquitination of phosphoglycerate dehydrogenase promotes colorectal cancer metastasis via increased S-adenosylmethionine

Although serine metabolism plays a crucial role in the proliferation and survival of tumor cells, how it supports tumor cell migration remains poorly understood. Phosphoglycerate dehydrogenase (PHGDH) catalyzes the oxidation of 3-phosphoglycerate to 3-phosphonooxypyruvate, the first committed step in de novo serine biosynthesis. Here we show that PHGDH was monoubiquitinated by cullin 4A-based E3 ligase complex at lysine 146 in colorectal cancer (CRC) cells, which enhanced PHGDH activity by recruiting a chaperone protein, DnaJ homolog subfamily A member 1, to promote its tetrameric formation, thereby increasing the levels of serine, glycine, and S-adenosylmethionine (SAM). Increased levels of SAM upregulated the expression of cell adhesion genes (laminin subunit gamma 2 and cysteine rich angiogenic inducer 61) by initiating SET domain containing 1A-mediated trimethylation of histone H3K4, thereby promoting tumor cell migration and CRC metastasis. Intriguingly, SAM levels in tumors or blood samples correlated with the metastatic recurrence of patients with CRC. Our finding not only reveals a potentially new role and mechanism of SAM-promoted tumor metastasis but also demonstrates a regulatory mechanism of PHGDH activity by monoubiquitination.

Unraveling the functional role of DNA demethylation at specific promoters by targeted steric blockage of DNA methyltransferase with CRISPR/dCas9

Despite four decades of research to support the association between DNA methylation and gene expression, the causality of this relationship remains unresolved. Here, we reaffirm that experimental confounds preclude resolution of this question with existing strategies, including recently developed CRISPR/dCas9 and TET-based epigenetic editors. Instead, we demonstrate a highly effective method using only nuclease-dead Cas9 and guide RNA to physically block DNA methylation at specific targets in the absence of a confounding flexibly-tethered enzyme, thereby enabling the examination of the role of DNA demethylation per se in living cells, with no evidence of off-target activity. Using this method, we probe a small number of inducible promoters and find the effect of DNA demethylation to be small, while demethylation of CpG-rich FMR1 produces larger changes in gene expression. This method could be used to reveal the extent and nature of the contribution of DNA methylation to gene regulation.

The Crucial Roles of Intermediate Metabolites in Cancer

Metabolic alteration, one of the hallmarks of cancer cells, is important for cancer initiation and development. To support their rapid growth, cancer cells alter their metabolism so as to obtain the necessary energy and building blocks for biosynthetic pathways, as well as to adjust their redox balance. Once thought to be merely byproducts of metabolic pathways, intermediate metabolites are now known to mediate epigenetic modifications and protein post-transcriptional modifications (PTM), as well as connect cellular metabolism with signal transduction. Consequently, they can affect a myriad of processes, including proliferation, apoptosis, and immunity. In this review, we summarize multiple representative metabolites involved in glycolysis, the pentose phosphate pathway (PPP), the tricarboxylic acid (TCA) cycle, lipid synthesis, ketogenesis, methionine metabolism, glutamine metabolism, and tryptophan metabolism, focusing on their roles in chromatin and protein modifications and as signal-transducing messengers.

S-Adenosylmethionine Treatment of Colorectal Cancer Cell Lines Alters DNA Methylation, DNA Repair and Tumor Progression-Related Gene Expression

Global DNA hypomethylation is a characteristic feature of colorectal carcinoma (CRC). The tumor inhibitory effect of S-adenosylmethionine (SAM) methyl donor has been described in certain cancers including CRC. However, the molecular impact of SAM treatment on CRC cell lines with distinct genetic features has not been evaluated comprehensively. HT-29 and SW480 cells were treated with 0.5 and 1 mmol/L SAM for 48 h followed by cell proliferation measurements, whole-genome transcriptome and methylome analyses, DNA stability assessments and exome sequencing. SAM reduced cell number and increased senescence by causing S phase arrest, besides, multiple EMT-related genes (e.g., TGFB1) were downregulated in both cell lines. Alteration in the global DNA methylation level was not observed, but certain methylation changes in gene promoters were detected. SAM-induced γ-H2AX elevation could be associated with activated DNA repair pathway showing upregulated gene expression (e.g., HUS1). Remarkable genomic stability elevation, namely, decreased micronucleus number and comet tail length was observed only in SW480 after treatment. SAM has the potential to induce senescence, DNA repair, genome stability and to reduce CRC progression. However, the different therapeutic responses of HT-29 and SW480 to SAM emphasize the importance of the molecular characterization of CRC cases prior to methyl donor supplementation.

Epigenetical Targeting of the FOXP3 Gene by S-Adenosylmethionine Diminishes the Suppressive Capacity of Regulatory T Cells Ex Vivo and Alters the Expression Profiles

Regulatory T cells (Treg cells), a subgroup of CD4 lymphocytes, play a crucial role in serving as an immune suppressor and in maintaining peripheral tolerance. As the accumulation of Treg cells in the tumor microenvironment is significantly associated with a decreased survival time of patients, they are considered as an important therapeutic target in the immunotherapy of human cancers. These cells are either derived from the thymus, which are called (CD4CD25CD127) natural Treg cells (nTreg cells), or they are generated from CD4CD25 naive T cells by transforming growth factor-beta 1 and interleukin 2 (IL-2) in the periphery, which are called induced Treg cells (iTreg cells). Although iTreg cells are unstable, nTreg cells stably express forkhead box P3 (FOXP3) protein. Moreover, nTreg cells can be classified as memory (CD45RA) and naive (CD45RA) Treg cells, and this classification is based on the expression of CD45RA. FOXP3, which is a master regulator transcription factor, is essential for the functions of Treg cells, and it is mainly controlled by epigenetic mechanisms. The cyclooxygenase 2 (COX2)/prostaglandin E2 (PGE2) pathway is also reported to contribute to the regulatory functions of tumor-infiltrating Treg cells. As a new approach, we investigated whether S-adenosylmethionine (SAM), a substrate of DNA methyltransferase, attenuates the immune-suppressive capacity of the naive subtype of nTreg cells (CD4CD25CD127CD45RA). Moreover, we examined the effects of PGE2/COX2 pathway blockers on the suppressive capacity of Treg cells. We found that SAM diminished the suppression competency of Treg cells by decreasing the FOXP3 mRNA and protein levels in a dose-dependent manner. SAM increased the DNA methylation of FOXP3 at the first intron site. In addition, SAM decreased the mRNA and protein levels of the IL-10 cytokine, which has suppressive roles in the immune system. Moreover, mRNA levels of interferon gamma (IFNG) were found to be increased. COX2 inhibition and blockage of PGE2 receptors also reduced the protein and mRNA levels of IL-10, but they did not exhibit any significant effect on Treg cells' suppression in the coculture system. Our results show that SAM might be considered and investigated as a promising agent for immunotherapy in the future.

Integrative Analysis Reveals Comprehensive Altered Metabolic Genes Linking with Tumor Epigenetics Modification in Pan-Cancer

Background

Cancer cells undergo various rewiring of metabolism and dysfunction of epigenetic modification to support their biosynthetic needs. Although the major features of metabolic reprogramming have been elucidated, the global metabolic genes linking epigenetics were overlooked in pan-cancer.

Objectives

Identifying the critical metabolic signatures with differential expressions which contributes to the epigenetic alternations across cancer types is an urgent issue for providing the potential targets for cancer therapy.

Method

The differential gene expression and DNA methylation were analyzed by using the 5726 samples data from the Cancer Genome Atlas (TCGA).

Results

Firstly, we analyzed the differential expression of metabolic genes and found that cancer underwent overall metabolism reprogramming, which exhibited a similar expression trend with the data from the Gene Expression Omnibus (GEO) database. Secondly, the regulatory network of histone acetylation and DNA methylation according to altered expression of metabolism genes was summarized in our results. Then, the survival analysis showed that high expression of DNMT3B had a poorer overall survival in 5 cancer types. Integrative altered methylation and expression revealed specific genes influenced by DNMT3B through DNA methylation across cancers. These genes do not overlap across various cancer types and are involved in different function annotations depending on the tissues, which indicated DNMT3B might influence DNA methylation in tissue specificity.

Conclusions

Our research clarifies some key metabolic genes, ACLY, SLC2A1, KAT2A, and DNMT3B, which are most disordered and indirectly contribute to the dysfunction of histone acetylation and DNA methylation in cancer. We also found some potential genes in different cancer types influenced by DNMT3B. Our study highlights possible epigenetic disorders resulting from the deregulation of metabolic genes in pan-cancer and provides potential therapy in the clinical treatment of human cancer.

Epigenetic Targets in Synovial Sarcoma: A Mini-Review

Synovial Sarcomas (SS) are a type of Soft Tissue Sarcoma (STS) and represent 8-10% of all STS cases. Although SS can arise at any age, it typically affects younger individuals aged 15-35 and is therefore part of both pediatric and adult clinical practices. SS occurs primarily in the limbs, often near joints, but can present anywhere. It is characterized by the recurrent pathognomonic chromosomal translocation t(X;18)(p11.2;q11.2) that most frequently fuses SSX1 or SSX2 genes with SS18. This leads to the expression of the SS18-SSX fusion protein, which causes disturbances in several interacting multiprotein complexes such as the SWItch/Sucrose Non-Fermentable (SWI/SNF) complex, also known as the BAF complex and the Polycomb Repressive Complex 1 and 2 (PRC1 and PRC2). Furthermore, this promotes widespread epigenetic rewiring, leading to aberrant gene expression that drives the pathogenesis of SS. Good prognoses are characterized predominantly by small tumor size and young patient age. Whereas, high tumor grade and an increased genomic complexity of the tumor constitute poor prognostic factors. The current therapeutic strategy relies on chemotherapy and radiotherapy, the latter of which can lead to chronic side effects for pediatric patients. We will focus on the known roles of SWI/SNF, PRC1, and PRC2 as the main effectors of the SS18-SSX-mediated genome modifications and we present existing biological rationale for potential therapeutic targets and treatment strategies.

Metabolic Intermediates in Tumorigenesis and Progression

Traditional antitumor drugs inhibit the proliferation and metastasis of tumour cells by restraining the replication and expression of DNA. These drugs are usually highly cytotoxic. They kill tumour cells while also cause damage to normal cells at the same time, especially the hematopoietic cells that divide vigorously. Patients are exposed to other serious situations such as a severe infection caused by a decrease in the number of white blood cells. Energy metabolism is an essential process for the survival of all cells, but differs greatly between normal cells and tumour cells in metabolic pathways and metabolic intermediates. Whether this difference could be used as new therapeutic target while reducing damage to normal tissues is the topic of this paper. In this paper, we introduce five major metabolic intermediates in detail, including acetyl-CoA, SAM, FAD, NAD⁺ and THF. Their contents and functions in tumour cells and normal cells are significantly different. And the possible regulatory mechanisms that lead to these differences are proposed carefully. It is hoped that the key enzymes in these regulatory pathways could be used as new targets for tumour therapy.

Targeting DNA Hypomethylation in Malignancy by Epigenetic Therapies

DNA methylation is a chemically reversible epigenetic modification that regulates the chromatin structure and gene expression, and thereby takes part in various cellular processes like embryogenesis, genomic imprinting, X-chromosome inactivation, and genome stability. Alterations in the normal methylation levels of DNA may contribute to the development of pathological conditions like cancer. Even though both hypo- and hypermethylation-mediated abnormalities are prevalent in the cancer genome, the field of cancer epigenetics has been more focused on targeting hypermethylation. As a result, DNA hypomethylation-mediated abnormalities remained relatively less explored, and currently, there are no approved drugs that can be clinically used to target hypomethylation. Understanding the precise role of DNA hypomethylation is not only crucial from a mechanistic point of view but also for the development of pharmacological agents that can reverse the hypomethylated state of the DNA. This chapter focuses on the causes and impact of DNA hypomethylation in the development of cancer and describes the possible ways to pharmacologically target it, especially by using a naturally occurring physiologic agent S-adenosylmethionine (SAM).

Genetic regulation of longevity and age-associated diseases through the methionine sulfoxide reductase system

Methionine sulfoxide reductase enzymes are a protective system against biological oxidative stress in aerobic organisms. Modifications to this antioxidant system have been shown to impact the lifespan of several model system organisms. In humans, methionine oxidation of critical proteins and deficiencies in the methionine sulfoxide reductase system have been linked to age-related diseases, including cancer and neurodegenerative disease. Substrates for methionine sulfoxide reductases have been reviewed multiple times, and are still an active area of discovery. In contrast, less is known about the genetic regulation of methionine sulfoxide reductases. In this review, we discuss studies on the genetic regulation of the methionine sulfoxide reductase system with relevance to longevity and age-related diseases. A better understanding of genetic regulation for methionine sulfoxide reductases may lead to new therapeutic approaches for age-related diseases in the future.

A novel mechanism of the M1-M2 methionine adenosyltransferase switch-mediated hepatocellular carcinoma metastasis

Hepatocellular carcinoma (HCC) manifests as a highly metastatic cancer with extremely poor prognosis. However, mechanisms underlying metastasis of HCC are not fully understood. Here, we showed that switching gene expression from MAT1A to MAT2A (M1-M2 switch) promoted cancer invasion and metastasis. Reversion of the M1-M2 switch repressed, whereas enhancing the M1-M2 switch promoted the ability of HCC cells to metastasize. Moreover, we provided clinical data showing that tipping the balance between MAT1A and MAT2A expression correlated with increased metastasis and inferior recurrence-free survival in HCC patients. Molecular pathways analysis showed that downregulation of MAT1A, which augmented osteopontin (OPN) expression through decreasing methylation of the OPN promoter, and MAT2A upregulation, which induced integrin β3 (ITGB3) expression by binding to ITGB3 promoter, collaboratively triggered ERK signaling and thereby promoted metastasis. Thus, the simultaneous downregulation of MAT1A and upregulation of MAT2A are necessary and sufficient for HCC metastasis in the process of M1-M2 switch. Our findings provide novel mechanistic insights into cancer metastasis. Inhibition and prevention of the M1-M2 switch would offer a novel therapeutic option for treatment of HCC.

Enhanced S-Adenosylmethionine Production by Increasing ATP Levels in Baker's Yeast ( Saccharomyces cerevisiae)

In the biosynthesis of S-adenosylmethionine (SAM) in baker's yeast ( Saccharomyces cerevisiae), ATP functions as both a precursor and a driving force. However, few published reports have dealt with the control of ATP concentration using genetic design. In this study we have adopted a new ATP regulation strategy in yeast for enhancing SAM biosynthesis, including altering NADH availability and regulating the oxygen supply. Different ATP regulation systems were designed based on the introduction of water-forming NADH oxidase, Vitreoscilla hemoglobin, and phosphite dehydrogenase in combination with overexpression of the gene SAM2. Via application of this strategy, after 28 h cultivation, the SAM titer in the yeast strain ABYSM-2 reached a maximum level close to 55 mg/L, an increase of 67% compared to the control strain. The results show that the ATP regulation strategy is a valuable tool for SAM production and might further enhance the synthesis of other ATP-driven metabolites in yeast.

S-adenosylmethionine and methylthioadenosine inhibit cancer metastasis by targeting microRNA 34a/b-methionine adenosyltransferase 2A/2B axis

MicroRNA-34a (miR-34a) is down-regulated in colorectal cancers (CRC) and required for interleukin-6 (IL-6)-induced CRC metastasis. Mice lacking miR-34a developed more invasive cancer in a colitis-associated cancer model. In the same model, S-adenosylmethionine (SAMe) and methylthioadenosine (MTA) inhibited IL-6/STAT3 and lowered tumor burden. SAMe and MTA reduce the expression of methionine adenosyltransferase 2A (MAT2A) and there are consensus binding sites for miR-34a/b in the MAT2A 3’UTR. Here we examined whether SAMe/MTA influence miR-34a/b expression and cancer metastasis. We found SAMe and MTA raised miR-34a/b expression in CRC cell lines, inhibited migration and invasion in vitro and liver metastasis in vivo. Like CRC, MAT2A and MAT2B expression is induced in human pancreas and prostate cancers. Treatment with SAMe, MTA, miR-34a or miR-34b inhibited MAT2A expression mainly at the protein level. MAT2B protein level also fell because MAT2A and MAT2B enhance each other’s protein stability. Overexpressing miR-34a or miR-34b inhibited while MAT2A or MAT2B enhanced CRC migration and invasion. Co-expressing either miR-34a/b had minimal to no effect on MAT2A/MAT2B’s ability to increase migration, invasion and growth. Taken together, MAT2A and MAT2B are important targets of miR-34a/b and SAMe and MTA target this axis, suppressing MAT2A/MAT2B while raising miR-34a/b expression, inhibiting cancer metastasis.

The Genomic Impact of DNA CpG Methylation on Gene Expression; Relationships in Prostate Cancer

The process of DNA CpG methylation has been extensively investigated for over 50 years and revealed associations between changing methylation status of CpG islands and gene expression. As a result, DNA CpG methylation is implicated in the control of gene expression in developmental and homeostasis processes, as well as being a cancer-driver mechanism. The development of genome-wide technologies and sophisticated statistical analytical approaches has ushered in an era of widespread analyses, for example in the cancer arena, of the relationships between altered DNA CpG methylation, gene expression, and tumor status. The remarkable increase in the volume of such genomic data, for example, through investigators from the Cancer Genome Atlas (TCGA), has allowed dissection of the relationships between DNA CpG methylation density and distribution, gene expression, and tumor outcome. In this manner, it is now possible to test that the genome-wide correlations are measurable between changes in DNA CpG methylation and gene expression. Perhaps surprisingly is that these associations can only be detected for hundreds, but not thousands, of genes, and the direction of the correlations are both positive and negative. This, perhaps, suggests that CpG methylation events in cancer systems can act as disease drivers but the effects are possibly more restricted than suspected. Additionally, the positive and negative correlations suggest direct and indirect events and an incomplete understanding. Within the prostate cancer TCGA cohort, we examined the relationships between expression of genes that control DNA methylation, known targets of DNA methylation and tumor status. This revealed that genes that control the synthesis of S-adenosyl-l-methionine (SAM) associate with altered expression of DNA methylation targets in a subset of aggressive tumors.