Unraveling the immune response of the spleen in sepsis using green-synthesized silver nanoparticles from pomegranate peel extracts

Sepsis is a serious disease characterized by an inappropriate host response to infection, resulting in widespread inflammation and systemic organ failure. The aim of this research is to investigate the possibility of pomegranate peel-derived silver nanoparticles (PGNP) as a potential alternative therapy for sepsis. Characterization using transmission electron microscopy revealed 10-30 nm spherical nanoparticles. In a rat model of sepsis, PGNP treatment improved spleen health, histology, and immune response as compared with septic rats. In rats treated with PGNP during sepsis, significant alterations in oxidative stress markers (p < .01) were observed. These included elevated levels of glutathione (0.63 ± 0.08 mmol/mg protein), reduced concentrations of nitric oxide (8.7 ± 0.8 μ mol/mg protein) and malondialdehyde (2.2 ± 0.3 nmol/mg protein), as well as increased activity of superoxide dismutase (159 ± 33 U/mg protein). Following PGNP administration, gene expression analysis revealed a decrease in spleen IL-1β, IL-6, and TNF-α, highlighting its anti-inflammatory potential. Furthermore, PGNP effectively controlled apoptosis-related genes (Bax, Bcl-2, and Casp3), indicating its role in cellular survival pathways. This study sheds light on the immunological regulation of the spleen during sepsis using PGNP, demonstrating its potential as a new effective treatment approach. The study emphasizes the necessity of continuing to investigate and develop alternative medicines, particularly in light of antibiotic resistance and the global impact of sepsis. RESEARCH HIGHLIGHTS: The study explored the potential medicinal benefits of pomegranate peel-derived silver nanoparticles (PGNP) in the treatment of sepsis. PGNP suppressed pro-inflammatory cytokines and enhanced the immune response. The study recommends PGNP as a viable substitute treatment.

CD133-Dependent Activation of Phosphoinositide 3-Kinase /AKT/Mammalian Target of Rapamycin Signaling in Melanoma Progression and Drug Resistance

Melanoma frequently harbors genetic alterations in key molecules leading to the aberrant activation of PI3K and its downstream pathways. Although the role of PI3K/AKT/mTOR in melanoma progression and drug resistance is well documented, targeting the PI3K/AKT/mTOR pathway showed less efficiency in clinical trials than might have been expected, since the suppression of the PI3K/mTOR signaling pathway-induced feedback loops is mostly associated with the activation of compensatory pathways such as MAPK/MEK/ERK. Consequently, the development of intrinsic and acquired resistance can occur. As a solid tumor, melanoma is notorious for its heterogeneity. This can be expressed in the form of genetically divergent subpopulations including a small fraction of cancer stem-like cells (CSCs) and non-cancer stem cells (non-CSCs) that make the most of the tumor mass. Like other CSCs, melanoma stem-like cells (MSCs) are characterized by their unique cell surface proteins/stemness markers and aberrant signaling pathways. In addition to its function as a robust marker for stemness properties, CD133 is crucial for the maintenance of stemness properties and drug resistance. Herein, the role of CD133-dependent activation of PI3K/mTOR in the regulation of melanoma progression, drug resistance, and recurrence is reviewed.

Mechanisms of Melanoma Progression and Treatment Resistance: Role of Cancer Stem-like Cells

Melanoma is the third most common type of skin cancer, characterized by its heterogeneity and propensity to metastasize to distant organs. Melanoma is a heterogeneous tumor, composed of genetically divergent subpopulations, including a small fraction of melanoma-initiating cancer stem-like cells (CSCs) and many non-cancer stem cells (non-CSCs). CSCs are characterized by their unique surface proteins associated with aberrant signaling pathways with a causal or consequential relationship with tumor progression, drug resistance, and recurrence. Melanomas also harbor significant alterations in functional genes (BRAF, CDKN2A, NRAS, TP53, and NF1). Of these, the most common are the BRAF and NRAS oncogenes, with 50% of melanomas demonstrating the BRAF mutation (BRAFV600E). While the successful targeting of BRAFV600E does improve overall survival, the long-term efficacy of available therapeutic options is limited due to adverse side effects and reduced clinical efficacy. Additionally, drug resistance develops rapidly via mechanisms involving fast feedback re-activation of MAPK signaling pathways. This article updates information relevant to the mechanisms of melanoma progression and resistance and particularly the mechanistic role of CSCs in melanoma progression, drug resistance, and recurrence.

Nephroprotective Efficacy of Echinops spinosus against a Glycerol-Induced Acute Kidney Injury Model

Nephroprotection or renal rescue is to revive and restore kidney function after damage, with no need for further dialysis. During acute kidney injury (AKI), sudden and recent reductions in kidney functions occur. Causes are multiple, and prompt intervention can be critical to diminish or prevent morbidity. Echinops spinosus (ES) is a curative plant with proven pharmacological and biological effects including anti-inflammatory, antioxidant, and antibacterial competencies. The principal goal of this research is to scrutinize the nephroprotective features of E. spinosa extract (ESE) against glycerol-induced AKI. Male Wistar albino rats were equally divided into five separated groups: negative control rats (vehicle-injected), ESE control rats (ESE-treated rats), positive control rats, glycerol-induced AKI-model rats (single IM injection of 50% glycerol), and 2 groups of diseased rats but pretreated with different concentrations of ESE for 7 days (ESE150 + AKI rats and ESE250 + AKI rats). Kidney tissues were collected and used for histopathology analysis. The relative kidney weight percentage was assessed. ESE effects were investigated via scanning several biomarkers, such as serum urea and creatinine, as kidney function biomarkers. Lactate dehydrogenase (LDH) and creatine kinase (CK) activities were examined as rhabdomyolysis (RM) indicators. Kidney injury molecule-1 (Kim-1) and neutrophil gelatinase-associated lipocalin (NGAL) were also examined to investigate kidney injury. Enzymatic and nonenzymatic oxidative stress markers were analyzed, namely, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), malondialdehyde (MDA), nitric oxide (NO), and reduced glutathione GSH. Proinflammatory cytokine [tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β)] and the renal proapoptotic protein (Bax) and antiapoptotic protein (Bcl-2) levels were evaluated. Statistical analysis for the resulting data revealed that ESE pretreatment turned AKI-induced biological antioxidant levels to an extent comparable to normal results. Furthermore, ESE decreased kidney function markers and RM-related biomarkers (LDH, CK, Kim-1, and NGAL) compared to those in untreated AKI-model rats. ESE treatment dropped the apoptotic renal Bax levels, enhanced antiapoptotic Bcl-2 manufacture, and disallowed the release of IL-1β and TNF-α. This study revealed the protective effect of ESE as therapeutic medicine against AKI-encouraged oxidative stress, inflammation, and apoptosis. It can be effectively used as adjuvant therapy, helping in renal rescue, and for kidney healing in cases with risk factors of AKI.

Tumor Microenvironment as a Therapeutic Target in Melanoma Treatment

The role of the tumor microenvironment in tumor growth and therapy has recently attracted more attention in research and drug development. The ability of the microenvironment to trigger tumor maintenance, progression, and resistance is the main cause for treatment failure and tumor relapse. Accumulated evidence indicates that the maintenance and progression of tumor cells is determined by components of the microenvironment, which include stromal cells (endothelial cells, fibroblasts, mesenchymal stem cells, and immune cells), extracellular matrix (ECM), and soluble molecules (chemokines, cytokines, growth factors, and extracellular vesicles). As a solid tumor, melanoma is not only a tumor mass of monolithic tumor cells, but it also contains supporting stroma, ECM, and soluble molecules. Melanoma cells are continuously in interaction with the components of the microenvironment. In the present review, we focus on the role of the tumor microenvironment components in the modulation of tumor progression and treatment resistance as well as the impact of the tumor microenvironment as a therapeutic target in melanoma.

Induction of Antimicrobial Protein S100A15 Expression by Oral Microbial Pathogens Is Toll-like Receptors-Dependent Activation of c-Jun-N-Terminal Kinase (JNK), p38, and NF-κB Pathways

The antimicrobial protein S100A15 belongs to the S100 family, which is differentially expressed in a variety of normal and pathological tissues. Although the function of S100A15 protein has been discussed in several studies, its induction and regulation in oral mucosa, so far, are largely unknown. In this study, we demonstrate that S100A15 is induced by the stimulation of oral mucosa with gram− or gram+ bacterial pathogens, as well as with the purified membrane components, namely lipopolysaccharides (LPS) and lipoteichoic acid (LTA). The stimulation of the human gingival fibroblast (GF) and the human mouth epidermal carcinoma (KB) cell lines with either gram− or gram+ bacterial pathogens or their purified membrane components (LPS and LTA) results in the activation of NF-κB, apoptosis-regulating kinase1 (ASK1), and MAP kinase signaling pathways including, c-Jun N-terminal kinase (JNK) and p38 together with their physiological substrates AP-1 and ATF-2, respectively. Inhibition of S100A15 by antibodies-mediated Toll-like receptor 4 (TLR4) or Toll-like receptor 2 (TLR2) neutralization reveals the induction of S100A15 protein by LPS/gram− bacterial pathogens to be TLR4- dependent mechanism, whereas induction by LTA/gram+ bacterial pathogens to be TLR2- dependent mechanism. Pre-treatment of GF and KB cells with JNK (SP600125), p38 (SB-203580), or NF-κB (Bay11-7082) specific inhibitors further demonstrates the importance of JNK, p38 and NF-κB pathways in the regulation of gram−/gram+ bacterial pathogen-induced S100A15 expression. Our data provide evidence that S100A15 is induced in cancer and non-cancer oral mucosa-derived cell lines by gram−/gram+ bacterial pathogens and provide insight into the molecular mechanisms by which gram− and gram+ bacterial pathogens induce S100A15 expression in the oral mucosa.

Consistent DNA Hypomethylations in Prostate Cancer

With approximately 1.4 million men annually diagnosed with prostate cancer (PCa) worldwide, PCa remains a dreaded threat to life and source of devastating morbidity. In recent decades, a significant decrease in age-specific PCa mortality has been achieved by increasing prostate-specific antigen (PSA) screening and improving treatments. Nevertheless, upcoming, augmented recommendations against PSA screening underline an escalating disproportion between the benefit and harm of current diagnosis/prognosis and application of radical treatment standards. Undoubtedly, new potent diagnostic and prognostic tools are urgently needed to alleviate this tensed situation. They should allow a more reliable early assessment of the upcoming threat, in order to enable applying timely adjusted and personalized therapy and monitoring. Here, we present a basic study on an epigenetic screening approach by Methylated DNA Immunoprecipitation (MeDIP). We identified genes associated with hypomethylated CpG islands in three PCa sample cohorts. By adjusting our computational biology analyses to focus on single CpG-enriched 60-nucleotide-long DNA probes, we revealed numerous consistently differential methylated DNA segments in PCa. They were associated among other genes with NOTCH3, CDK2AP1, KLK4, and ADAM15. These can be used for early discrimination, and might contribute to a new epigenetic tumor classification system of PCa. Our analysis shows that we can dissect short, differential methylated CpG-rich DNA fragments and combinations of them that are consistently present in all tumors. We name them tumor cell-specific differential methylated CpG dinucleotide signatures (TUMS).

Differential DNA Methylation of THOR and hTAPAS in the Regulation of hTERT and the Diagnosis of Cancer

Simple Summary

Because of its high prevalence of >45% in 9 out of 11 (82%) cancer types screened, THOR hypermethylation has been suggested to be a frequent telomerase-activating mechanism in hTERT-expressing tumor types, e.g., in cancers of the prostate, breast, blood, colon, lung, bladder, and brain. In this prime example, we present detailed DNA methylation profiles in urothelial cancer that reveal the exact positions of the most differentially methylated CpG dinucleotides within the THOR region in order to design an efficient Methylation-Specific PCR (MSPCR) approach for diagnostic and prognostic purposes. Furthermore, our data suggest an epigenetic mechanism regulating hTERT expression through the methylation status of THOR and lncRNA hTAPAS.

Abstract

Background: Although DNA methylation in the gene promoters usually represses gene expression, the TERT hypermethylated oncological region (THOR) located 5′ of the hTERT gene is hypermethylated when hTERT is expressed in diverse cancer types, including urothelial cancer (UC). Methods: Comprehensive MeDIP and DNA methylation array analyses complemented by the technically independent method of bisulfite genomic sequencing were applied on pathologically reviewed and classified urothelial carcinoma specimens and healthy urothelial tissue samples to reveal the methylation status of THOR in detail. Results: The detailed DNA methylation profiles reveal the exact positions of differentially methylated CpG dinucleotides within THOR in urothelial cancer and provide evidence ofa diverging role of methylation of these CpGs in the regulation of hTERT. In particular, our data suggest a regulating mechanism in which THOR methylation acts on hTERT expression through epigenetic silencing of the lncRNA hTERT antisense promoter-associated (hTAPAS), which represses hTERT. Conclusions: These findings precisely define the most differentially methylated CpGs of THOR in early urothelial cancer, enabling optimal design of Methylation-Specific PCR (MSPCR) primers to reliably probe these methylation differences for diagnostic and prognostic purposes. In addition, this strategy presents a prime example that is also applicable to many other malignancies. Finally, the first evidence for the underlying epigenetic mechanism regulating hTERT expression through the methylation status of THOR is provided.

Methyl Group Metabolism in Differentiation, Aging, and Cancer

Methyl group metabolism belongs to a relatively understudied field of research. Its importance lies in the fact that methyl group metabolic pathways are crucial for the successful conversion of dietary nutrients into the basic building blocks to carry out any cellular methylation reaction. Methyl groups play essential roles in numerous cellular functions such as DNA methylation, nucleotide- and protein biosynthesis. Especially, DNA methylation is responsible for organizing the genome into transcriptionally silent and active regions. Ultimately, it is this proper annotation that determines the quality of expression patterns required to ensure and shape the phenotypic integrity and function of a highly specialized cell type. Life is characterized by constantly changing environmental conditions, which are addressed by changes in DNA methylation. This relationship is increasingly coming into focus as it is of fundamental importance for differentiation, aging, and cancer. The stability and permanence of these metabolic processes, fueling the supplementation of methyl groups, seem to be important criteria to prevent deficiencies and erosion of the methylome. Alterations in the metabolic processes can lead to epigenetic and genetic perturbations, causative for diverse disorders, accelerated aging, and various age-related diseases. In recent decades, the intake of methyl group compounds has changed significantly due to, e.g., environmental pollution and food additives. Based on the current knowledge, this review provides a brief overview of the highly interconnected relationship between nutrition, metabolism, changes in epigenetic modifications, cancer, and aging. One goal is to provide an impetus to additionally investigate changes in DNA methylation as a possible consequence of an impaired methyl group metabolism.

Phyloepigenetics

Traditionally, phylogenetic interspecies relationships are estimated based on genetic diversity, since it is assumed that the more recently diverged a species, with comparable constancy of development, the more similar their genetic material and proteins should be. However, occasional controversies in the field may reflect limited resolution and accuracy of this approach. Epigenetics has, meanwhile, provided significant evidence that CpG dinucleotides (CpGs) within genetic material are of particular importance for the annotation and function of the genome and the formation of the phenotype, which is continuously shaped by evolutionary interaction with environmental factors. Based on this, it can be concluded that CpGs follow a distinct rate of evolution, compared to all other nucleotide positions. Evidence is provided that supports this conclusion. Therefore, using CpGs to fathom evolutionary relationships between species could turn out to be a valuable approach to achieve, in some cases, an improved understanding of evolutionary development.

Epigenetics in the Diagnosis and Therapy of Malignant Melanoma

Epigenetic mechanisms are fundamentally important for cancer initiation and development. However, a survey of the literature reveals that, to date, they appear less comprehensively investigated in melanoma than in many other cancers, e.g., prostate, breast, and colon carcinoma. The aim of this review is to provide a short summary of epigenetic aspects of functional relevance for melanoma pathogenesis. In addition, some new perspectives from epigenetic research in other cancers with potential for melanoma diagnosis and therapy are introduced. For example, the PrimeEpiHit hypothesis in urothelial carcinoma, which, similarly to malignant melanoma, can also be triggered by a single exogenous noxa, states that one of the first steps for cancer initiation could be epigenetic changes in key genes of one-carbon metabolism. The application of such insights may contribute to further progress in the diagnosis and therapy of melanoma, a deadly type of cancer.

Aging-associated distinctive DNA methylation changes of LINE-1 retrotransposons in pure cell-free DNA from human blood

LINE-1 hypomethylation of cell-free DNA has been described as an epigenetic biomarker of human aging. However, in the past, insufficient differentiation between cellular and cell-free DNA may have confounded analyses of genome-wide methylation levels in aging cells. Here we present a new methodological strategy to properly and unambiguously extract DNA methylation patterns of repetitive, as well as single genetic loci from pure cell-free DNA from peripheral blood. Since this nucleic acid fraction originates mainly in apoptotic, senescent and cancerous cells, this approach allows efficient analysis of aged and cancerous cell-specific DNA methylation patterns for diagnostic and prognostic purposes. Using this methodology, we observe a significant age-associated erosion of LINE-1 methylation in cfDNA suggesting that the threshold of hypomethylation sufficient for relevant LINE-1 activation and consequential harmful retrotransposition might be reached at higher age. We speculate that this process might contribute to making aging the main risk factor for many cancers.

Tumor necrosis factor-α triggers opposing signals in head and neck squamous cell carcinoma and induces apoptosis via mitochondrial- and non-mitochondrial-dependent pathways

Head and neck squamous cell carcinoma (HNSCC) remains one of the most common malignancies worldwide. Although the treatment outcomes of HNSCC have improved in recent years, the prognosis of patients with advanced-stage disease remains poor. Current treatment strategies for HNSCC include surgery as a primary therapy, while radio-, chemo-, and biotherapeutics can be applied as second-line therapy. Although tumor necrosis factor-α (TNF-α) is a potent tumor suppressor cytokine, the stimulation of opposing signals impairs its clinical utility as an anticancer agent. The aim of this study was to elucidate the mechanisms regulating TNF-α‑induced opposing signals and their biological consequences in HNSCC cell lines. We determined the molecular mechanisms of TNF-α-induced opposing signals in HNSCC cells. Our in vitro analysis indicated that one of these signals triggers apoptosis, while the other induces both apoptosis and cell survival. The TNF-α-induced survival of HNSCC cells is mediated by the TNF receptor-associated factor 2 (TRAF2)/nuclear factor (NF)-κB-dependent pathway, while TNF-α-induced apoptosis is mediated by mitochondrial and non-mitochondrial-dependent mechanisms through FADD-caspase-8-caspase-3 and ASK-JNK-p53-Noxa pathways. The localization of Noxa protein to both the mitochondria and endoplasmic reticulum (ER) was found to cause mitochondrial dysregulation and ER stress, respectively. Using inhibitory experiments, we demonstrated that the FADD‑caspase-8‑caspase-3 pathway, together with mitochondrial dysregulation and ER stress-dependent pathways, are essential for the modulation of apoptosis, and the NF-κB pathway is essential for the modulation of anti-apoptotic effects/cell survival during the exposure of HNSCC cells to TNF-α. Our data provide insight into the mechanisms of TNF-α-induced opposing signals in HNSCC cells and may further help in the development of novel therapeutic approaches with which to minimize the systemic toxicity of TNF-α.

Aberrant methylated key genes of methyl group metabolism within the molecular etiology of urothelial carcinogenesis

Urothelial carcinoma (UC), the most common cancer of the urinary bladder causes severe morbidity and mortality, e.g. about 40.000 deaths in the EU annually, and incurs considerable costs for the health system due to the need for prolonged treatments and long-term monitoring. Extensive aberrant  DNA methylation is described to prevail in urothelial carcinoma and is thought to contribute to genetic instability, altered gene expression and tumor progression. However, it is unknown how this epigenetic alteration arises during carcinogenesis. Intact methyl group metabolism is required to ensure maintenance of cell-type specific methylomes and thereby genetic integrity and proper cellular function. Here, using two independent techniques for detecting DNA methylation, we observed DNA hypermethylation of the 5'-regulatory regions of the key methyl group metabolism genes ODC1, AHCY and MTHFR in early urothelial carcinoma. These hypermethylation events are associated with genome-wide DNA hypomethylation which is commonly associated with genetic instability. We therefore infer that hypermethylation of methyl group metabolism genes acts in a feed-forward cycle to promote additional DNA methylation changes and suggest a new hypothesis on the molecular etiology of urothelial carcinoma.

Genome-wide hypomethylation of LINE-1 and Alu retroelements in cell-free DNA of blood is an epigenetic biomarker of human aging

Aging associated DNA hypomethylation of LINE-1 and Alu retroelements may be a crucial determinant of loss of genomic integrity, deterioration and cancer. In peripheral blood LINE-1 hypomethylation has been reported to increase during aging, but other studies did not observe significant changes. We hypothesized that these apparently inconsistent reports might relate to differences between cellular and cell-free DNA. Using the technique of idiolocal normalization of real-time methylation-specific PCR (IDLN-MSP) for genetic imbalanced DNA specimens we obtained evidence that LINE-1 hypomethylation in cell-free DNA, but not cellular DNA from peripheral blood is an epigenetic biomarker for human aging. Furthermore, hypomethylation of cell-free DNA is more extensive in smokers, suggesting that it might be used as a surrogate marker for monitoring the improvement of smoking-induced adverse effects after cancelling smoking.

Interferon gamma-induced apoptosis of head and neck squamous cell carcinoma is connected to indoleamine-2,3-dioxygenase via mitochondrial and ER stress-associated pathways

Background

Tumor response to immunotherapy is the consequence of a concerted crosstalk between cytokines and effector cells. Interferon gamma (IFNγ) is one of the common cytokines coordinating tumor immune response and the associated biological consequences. Although the role of IFNγ in the modulation of tumor immunity has been widely documented, the mechanisms regulating IFNγ-induced cell death, during the course of immune therapy, is not described in detail.

Results

IFNγ triggered apoptosis of CLS-354 and RPMI 2650 cells, enhanced the protein expression and activation of indoleamine 2,3-dioxygenase (IDO), and suppressed the basal expression of heme oxygenase-1(HO-1). Interestingly, IFNγ induced the loss of mitochondrial membrane potential (Δψm) and increased accumulation of reactive oxygen species (ROS). The cytokine also induced the activation of Janus kinase (JAK)/Signal Transducer and Activator of Transcription (STAT)1, apoptosis signal-regulating kinase 1 (ASK1), p38, c-jun-N-terminal kinase (JNK) and NF-κB pathways and the transcription factors STAT1, interferon regulatory factor 1 (IRF1), AP-1, ATF-2, NF-κB and p53, and expression of Noxa protein. Furthermore, IFNγ was found to trigger endoplasmic reticulum (ER) stress as evidenced by the cleavage of caspase-4 and activation of protein kinase RNA-like endoplasmic reticulum kinase (PERK) and inositol-requiring-1α (IRE1α) pathways. Using specific inhibitors, we identified a potential role for IDO as apoptotic mediator in the regulation of IFNγ-induced apoptosis of head and neck squamous cell carcinoma (HNSCC) cells via Noxa-mediated mitochondrial dysregulation and ER stress.

Conclusion

In addition to the elucidation of the role of IDO in the modulation of apoptosis, our study provides new insights into the molecular mechanisms of IFNγ-induced apoptosis of HNSCC cells during the course of immune therapy.

IDLN-MSP: Idiolocal normalization of real-time methylation-specific PCR for genetic imbalanced DNA specimens

Sensitive, accurate, and reliable measurements of tumor cell-specific DNA methylation changes are of fundamental importance in cancer diagnosis, prognosis, and monitoring. Real-time methylation-specific PCR (MSP) using intercalating dyes is an established method of choice for this purpose. Here we present a simple but crucial adaptation of this widely applied method that overcomes a major obstacle: genetic abnormalities in the DNA samples, such as aneuploidy or copy number variations, that could result in inaccurate results due to improper normalization if the copy numbers of the target and reference sequences are not the same. In our idiolocal normalization (IDLN) method, the locus for the normalizing, methylation-independent reference amplification is chosen close to the locus of the methylation-dependent target amplification. This ensures that the copy numbers of both the target and reference sequences will be identical in most cases if they are close enough to each other, resulting in accurate normalization and reliable comparative measurements of DNA methylation in clinical samples when using real-time MSP.

Age-Related Increase of EED Expression in Early Hematopoietic Progenitor Cells is Associated with Global Increase of the Histone Modification H3K27me3

Human hematopoietic stem and progenitor cells (HSPCs) from umbilical cord blood exhibit higher differentiation potential and repopulation capacity compared to adult HSPCs. The molecular basis for these functional differences is currently unknown. Upon screening for epigenetic effector genes being differentially expressed in neonatal and adult HSPC subpopulations, the Polycomb Repressive Complex 2 (PRC2) member EED was identified. Even though EED is expressed at comparable amounts in neonatal and adult multipotent HSPCs, early adult lineage committed progenitors of the lymphomyeloid (LM) and erythromyeloid lineages expressed higher EED amounts than neonatal HPCs. We demonstrate that EED overexpression directly leads to higher H3K27me3 levels, a repressive histone modification that is mediated by the PRC2 complex. Quantitative analysis of H3K27me3 levels by FPLC-based ELISA revealed elevated levels in primary blood cells from adults. Besides quantitative changes, gene ontology analysis of the genome-wide H3K27me3 distribution revealed qualitative changes in adult HSPCs with elevated levels in genes associated with nonhematopoietic development pathways. In contrast, H3K4me3 which labels active chromatin was enriched on hematopoietic genes. In vitro differentiation of EED-transfected neonatal HSPCs revealed aberrant expression of the myelopoietic marker CD14, suggesting that EED affects the lymphoid versus myeloid decision processes within the lymphomyeloid lineage. This is in line with LM progenitors having the most pronounced differences in EED expression. Highlighting the dynamic roles of epigenetic modifications in human hematopoiesis, the present data demonstrate shifts in the PRC2-associated histone modification H3K27me3 from birth to adulthood.

Erythroid differentiation of human induced pluripotent stem cells is independent of donor cell type of origin

Epigenetic memory in induced pluripotent stem cells, which is related to the somatic cell type of origin of the stem cells, might lead to variations in the differentiation capacities of the pluripotent stem cells. In this context, induced pluripotent stem cells from human CD34(+) hematopoietic stem cells might be more suitable for hematopoietic differentiation than the commonly used fibroblast-derived induced pluripotent stem cells. To investigate the influence of an epigenetic memory on the ex vivo expansion of induced pluripotent stem cells into erythroid cells, we compared induced pluripotent stem cells from human neural stem cells and human cord blood-derived CD34(+) hematopoietic stem cells and evaluated their potential for differentiation into hematopoietic progenitor and mature red blood cells. Although genome-wide DNA methylation profiling at all promoter regions demonstrates that the epigenetic memory of induced pluripotent stem cells is influenced by the somatic cell type of origin of the stem cells, we found a similar hematopoietic induction potential and erythroid differentiation pattern of induced pluripotent stem cells of different somatic cell origin. All human induced pluripotent stem cell lines showed terminal maturation into normoblasts and enucleated reticulocytes, producing predominantly fetal hemoglobin. Differences were only observed in the growth rate of erythroid cells, which was slightly higher in the induced pluripotent stem cells derived from CD34(+) hematopoietic stem cells. More detailed methylation analysis of the hematopoietic and erythroid promoters identified similar CpG methylation levels in the induced pluripotent stem cell lines derived from CD34(+) cells and those derived from neural stem cells, which confirms their comparable erythroid differentiation potential.

Vinblastine-induced apoptosis of melanoma cells is mediated by Ras homologous A protein (Rho A) via mitochondrial and non-mitochondrial-dependent mechanisms

Despite the availability of melanoma treatment at the primary site, the recurrence of local melanoma can metastasize to any distant organ. Currently, the available therapies for the treatment of metastatic melanoma are of limited benefit. Thus, the functional analysis of conventional therapies may help to improve their efficiency in the treatment of metastatic melanoma. In the present study, the exposure of melanoma cells to vinblastine was found to trigger apoptosis as evidenced by the loss of mitochondrial membrane potential, the release of both cytochrome c and apoptosis inducing factor, activation of caspase-9 and 3, and cleavage of Poly (ADP-ribose)-Polymerase. Also, vinblastine enhances the phosphorylation of Ras homologous protein A, the accumulation of reactive oxygen species, the release of intracellular Ca(2+), as well as the activation of apoptosis signal-regulating kinase 1, c-jun-N-terminal kinase, p38, inhibitor of kappaBα (IκBα) kinase, and inositol requiring enzyme 1α. In addition, vinblastine induces the DNA-binding activities of the transcription factor NF-κB, HSF1, AP-1, and ATF-2, together with the expression of HSP70 and Bax proteins. Moreover, inhibitory experiments addressed a central role for Rho A in the regulation of vinblastine-induced apoptosis of melanoma cells via mitochondrial and non-mitochondrial-dependent mechanisms. In conclusion, the present study addresses for the first time a central role for Rho A in the modulation of vinblastine-induced apoptosis of melanoma cells and thereby provides an insight into the molecular action of vinblastine in melanoma treatment.

Bortezomib/proteasome inhibitor triggers both apoptosis and autophagy-dependent pathways in melanoma cells

Generally, both endoplasmic reticulum (ER) stress and mitochondrial dysregulation are a potential therapeutic target of anticancer agents including bortezomib. The treatment of melanoma cells with bortezomib was found to induce apoptosis together with the upregulation of Noxa, Mcl-1, and HSP70 proteins, and the cleavage of LC3 and autophagic formation. Also, bortezomib induced ER-stress as evidenced by the increase of intracellular Ca(2+) release. In addition, bortezomib enhanced the phosphorylation of inositol-requiring transmembrane kinase and endonuclease 1α (IRE1α), apoptosis signal-regulating kinase 1 (ASK1), c-jun-N-terminal kinase (JNK) and p38, and the activation of the transcription factors AP-1, ATF-2, Ets-1, and HSF1. Bortezomib-induced mitochondrial dysregulation was associated with the accumulation of reactive oxygen species (ROS), the release of both apoptosis inducing factor (AIF) and cytochrome c, the activation of caspase-9 and caspase-3, and cleavage of Poly (ADP-ribose) polymerase (PARP). The pretreatment of melanoma cells with the inhibitor of caspase-3 (Ac-DEVD-CHO) was found to block bortezomib-induced apoptosis that subsequently led to the increase of autophagic formation. In contrast, the inhibition of ASK1 abrogated bortezomib-induced autophagic formation and increased apoptosis induction. Furthermore, the inhibition of JNK, of HSP70 also increased apoptosis induction without influence of bortezomib-induced autophagic formation. Based on the inhibitory experiments, the treatment with bortezomib triggers the activation of both ER-stress-associated pathways, namely IRE1α-ASK1-p38-ATF-2/ets-1-Mcl-1, and IRE1α-ASK1-JNK-AP-1/HSF1-HSP70 as well as mitochondrial dysregulation-associated pathways, namely ROS-ASK1-JNK-AP-1/HSF1-HS70, and AIF-caspase-3-PARP and Cyt.c, and caspase-9-caspase-3-PARP. Taken together, our data demonstrates for the first time the molecular mechanisms, whereby bortezomib triggers both apoptosis and autophagic formation in melanoma cells.

Methods for Separate Isolation of Cell-Free DNA and Cellular DNA from Urine-Application of Methylation-Specific PCR on both DNA Fractions

The analysis of genomic DNA is widely-used for research, forensic and diagnostic purposes. Here we describe reliable methods for isolation of cell-free DNA and cellular DNA from urine. Both DNA fractions are suitable for PCR and Methylation-Specific PCR (MSP) amplification, leading to consistent and reproducible results. A kinetics analysis describes the decline of efficiency of MSP performed with urinary DNA which had been stored at room temperature with and without proteinase K for various time periods.

Role of DNA methylation in miR-200c/141 cluster silencing in invasive breast cancer cells

BACKGROUND

The miR-200c/141 cluster has recently been implicated in the epithelial to mesenchymal transition (EMT) process. The expression of these two miRNAs is inversely correlated with tumorigenicity and invasiveness in several human cancers. The role of these miRNAs in cancer progression is based in part on their capacity to target the EMT activators ZEB1 and ZEB2, two transcription factors, which in turn repress expression of E-cadherin. Little is known about the regulation of the mir200c/141 cluster, whose targeting has been proposed as a promising new therapy for the most aggressive tumors.

FINDINGS

We show that the miR-200c/141 cluster is repressed by DNA methylation of a CpG island located in the promoter region of these miRNAs. Whereas in vitro methylation of the miR-200c/141 promoter led to shutdown of promoter activity, treatment with a demethylating agent caused transcriptional reactivation in breast cancer cells formerly lacking expression of miR-200c and miR-141. More importantly, we observed that DNA methylation of the identified miR-200c/141 promoter was tightly correlated with phenotype and the invasive capacity in a panel of 8 human breast cancer cell lines. In line with this, in vitro induction of EMT by ectopic expression of the EMT transcription factor Twist in human immortalized mammary epithelial cells (HMLE) was accompanied by increased DNA methylation and concomitant repression of the miR-200c/141 locus.

CONCLUSIONS

The present study demonstrates that expression of the miR-200c/141 cluster is regulated by DNA methylation, suggesting epigenetic regulation of this miRNA locus in aggressive breast cancer cell lines as well as untransformed mammary epithelial cells. This epigenetic silencing mechanism might represent a novel component of the regulatory circuit for the maintenance of EMT programs in cancer and normal cells.

Induction of pluripotency in human cord blood unrestricted somatic stem cells

OBJECTIVE

Generation of induced pluripotent stem (iPS) cells from human cord blood (CB)-derived unrestricted somatic stem cells and evaluation of their molecular signature and differentiation potential in comparison to human embryonic stem cells.

MATERIALS AND METHODS

Unrestricted somatic stem cells isolated from human CB were reprogrammed to iPS cells using retroviral expression of the transcription factors OCT4, SOX2, KLF4, and C-MYC. The reprogrammed cells were analyzed morphologically, by quantitative reverse transcription polymerase chain reaction, genome-wide microRNA and methylation profiling, and gene expression microarrays, as well as in their pluripotency potential by in vivo teratoma formation in severe combined immunodeficient mice and in vitro differentiation.

RESULTS

CB iPS cells are very similar to human embryonic stem cells morphologically, at their molecular signature, and in their differentiation potential.

CONCLUSIONS

Human CB-derived unrestricted somatic stem cells offer an attractive source of cells for generation of iPS cells. Our findings open novel perspectives to generate human leukocyte antigen-matched pluripotent stem cell banks based on existing CB banks. Besides the obvious relevance of a second-generation CB iPS cell bank for pharmacological and toxicological testing, its application for autologous or allogenic regenerative cell transplantation appears feasible.

Induction of indoleamine 2, 3-dioxygenase by death receptor activation contributes to apoptosis of melanoma cells via mitochondrial damage-dependent ROS accumulation

Although the induction of indoleamine 2, 3-dioxygenase (IDO) by several agents is well established, the mechanisms of its transcriptional regulation and those regulating its function as apoptotic mediator seem to be complex, agent-dependent, and cell type-specific. Besides their pro-apoptotic activity in melanoma cells, both anti-Fas agonist antibody (CH11) and the tumor necrosis factor (TNF)-alpha were found to induce IDO gene expression, the activation of apoptosis signal-regulating kinase (ASK1), and the activation of both c-Jun N-terminal kinase (JNK) and NF-kappaB pathways. In addition, the treatment of melanoma cells with CH11 or TNF-alpha induced the loss of mitochondrial membrane potential (Deltapsim), the accumulation of reactive oxygen species (ROS), the phosphorylation of Fas-associated domain (FADD), the cleavage of caspase-8, and truncation of Bid. Using RNA interference and pharmacological inhibitors, we could confirm the pro-apoptotic activity of IDO and address the mechanisms, which are responsible for its transcriptional regulation and the modulation of its pro-apoptotic activity during death receptor activation in melanoma cells. Thus, our data confirm the pro-apoptotic activity of IDO and provide an insight into the molecular mechanism of TNF-alpha and CH11-induced IDO expression, and the mechanism whereby IDO induces apoptosis of melanoma cells.

Induction of indoleamine 2, 3-dioxygenase by death receptor activation contributes to apoptosis of melanoma cells via mitochondrial damage-dependent ROS accumulation

Although the induction of indoleamine 2, 3-dioxygenase (IDO) by several agents is well established, the mechanisms of its transcriptional regulation and those regulating its function as apoptotic mediator seem to be complex, agent-dependent, and cell type-specific. Besides their pro-apoptotic activity in melanoma cells, both anti-Fas agonist antibody (CH11) and the tumor necrosis factor (TNF)-alpha were found to induce IDO gene expression, the activation of apoptosis signal-regulating kinase (ASK1), and the activation of both c-Jun N-terminal kinase (JNK) and NF-kappaB pathways. In addition, the treatment of melanoma cells with CH11 or TNF-alpha induced the loss of mitochondrial membrane potential (Deltapsim), the accumulation of reactive oxygen species (ROS), the phosphorylation of Fas-associated domain (FADD), the cleavage of caspase-8, and truncation of Bid. Using RNA interference and pharmacological inhibitors, we could confirm the pro-apoptotic activity of IDO and address the mechanisms, which are responsible for its transcriptional regulation and the modulation of its pro-apoptotic activity during death receptor activation in melanoma cells. Thus, our data confirm the pro-apoptotic activity of IDO and provide an insight into the molecular mechanism of TNF-alpha and CH11-induced IDO expression, and the mechanism whereby IDO induces apoptosis of melanoma cells.

Lineage-specific transition of histone signatures in the killer cell Ig-like receptor locus from hematopoietic progenitor to NK cells

The clonal distribution and stable expression of killer cell Ig-like receptor (KIR) genes is epigenetically regulated. To assess the epigenetic changes that occur during hemopoietic development we examined DNA methylation and chromatin structure of the KIR locus in early hemopoietic progenitor cells and major lymphocyte lineages. In hemopoietic progenitor cells, KIR genes exhibited the major hallmarks of epigenetic repression, which are dense DNA methylation, inaccessibility of chromatin to Micrococcus nuclease digest, and a repressive histone signature, characterized by strong H3K9 dimethylation and reduced H4K8 acetylation. In contrast, KIR genes of NK cells showed active histone signatures characterized by absence of H3K9 dimethylation and presence of H4K8 acetylation. Histone modifications correlated well with the competence of different lymphocyte lineages to express KIR; whereas H4K8 acetylation was high in NK and CD8+ T cells, it was almost absent in CD4+ T cells and B cells and, in the latter case, replaced by H3K9 dimethylation. In KIR-competent lineages, active histone signatures were also observed in silent KIR genes and in this case found in combination with dense DNA methylation of the promoter and nearby regions. The study suggests a two-step model of epigenetic regulation in which lineage-specific acquisition of euchromatic histone marks is a prerequisite for subsequent gene-specific DNA demethylation and expression of KIR genes.

Nucleolin regulates gene expression in CD34-positive hematopoietic cells

CD34 glycoprotein in human hematopoiesis is expressed on a subset of progenitor cells capable of self-renewal, multilineage differentiation, and hematopoietic reconstitution. Nucleolin is an abundant multifunctional phosphoprotein of growing eukaryotic cells, involved in regulation of gene transcription, chromatin remodeling, and RNA metabolism, whose transcripts are enriched in murine hematopoietic stem cells, as opposed to differentiated tissue. Here we show that, in human CD34-positive hematopoietic cells, nucleolin activates endogenous CD34 and Bcl-2 gene expression, and cell surface CD34 protein expression is thereby enhanced by nucleolin. Nucleolin-mediated activation of CD34 gene transcription results from direct sequence-specific interactions with the CD34 promoter region. Nucleolin expression prevails in CD34-positive cells mobilized into peripheral blood (PB), as opposed to CD34-negative peripheral blood mononuclear cells (PBMCs). Therefore, in intact CD34-positive mobilized PB cells, a recruitment of nucleolin to the CD34 promoter region takes place, accompanied by nucleosomal determinants of gene activity, which are absent from the CD34 promoter region in CD34-negative PBMCs. Our data show that nucleolin acts as a component of the gene regulation program of CD34-positive hematopoietic cells and provide further insights into processes by which human CD34-positive hematopoietic stem/progenitor cells are maintained.

Molecular characterization of KIR3DL3

Killer-cell immunoglobulin-like receptors (KIRs) are a structurally and functionally diverse family of molecules expressed by natural killer (NK) cells and T-cell subsets. The most centromeric gene in the human KIR cluster is KIR3DL3, a framework gene that is present in all haplotypes. KIR3DL3 has only one immunoreceptor tyrosine-based inhibitory motif and lacks the exon encoding the stem between the Immunoglobulin domains and the transmembrane region. We have investigated expression of KIR3DL3 in blood and decidual NK cells by reverse transcriptase polymerase chain reaction (RT-PCR) and protein analysis using a KIR3DL3-specific monoclonal antibody, CH21. KIR3DL3 mRNA was only detected in the CD56(bright) subset in cells from peripheral blood and in CD56(bright) decidual NK cells. The CD56(bright) NK92 cell line was also positive. Quantitative RT-PCR indicated a trend for higher expression of KIR3DL3 in female peripheral blood mononuclear cells compared to that in male. Using a bisulphite conversion method, we found that the promoter of KIR3DL3 was strongly methylated. Surface protein expression was detectable after demethylation. Like other KIRs, KIR3DL3 is highly polymorphic, and we detected 14 variants in 25 unrelated individuals. Nucleotide substitutions were scattered throughout the sequence, with a cluster of alleles at the start of the transmembrane region at the site where the remnant of the linking stem present in other KIR is found. We conclude that the KIR3DL3 gene is not a pseudogene but encodes a protein that is not expressed in healthy individuals. Protein expression might be induced under certain developmental or pathological situations.

Three Structurally and Functionally Divergent Kinds of Promoters Regulate Expression of Clonally Distributed Killer Cell Ig-Like Receptors (KIR), of KIR2DL4, and of KIR3DL3

The generation of killer cell Ig-like receptor (KIR) expression patterns in NK cells involves variegated silencing of KIR genes by DNA methylation. To identify regulatory elements involved in KIR gene activation, upstream regions of KIR genes were functionally characterized in NK3.3 cells as well as in primary NK cells. Three kinds of KIR promoters were defined, controlling clonally expressed KIR genes, the constitutively active KIR2DL4, and the weakly expressed KIR3DL3. Upstream of a short core promoter common to all KIR genes, a region containing functionally divergent elements was characterized. Although this region had no impact on the activity of the KIR2DL3 promoter, an inhibitory element was identified in the KIR2DL4 promoter and an activating element was found in the KIR3DL3 promoter. Upon treatment with a methyltransferase inhibitor, KIR3DL3 expression could be readily induced showing that the low levels of KIR3DL3 expression in peripheral blood are due to sustained DNA methylation of an otherwise fully functional promoter. Analysis of transcription factor binding sites identified a functional acute myeloid leukemia (AML) site common to all three KIR promoters. Mutation of this site led to a substantial increase in activity of all KIR promoters. Among the different members of the AML family, AML-2 was identified as the predominant KIR binding factor. The present study suggests that AML-2 acts as a repressor of KIR expression in mature NK cells and opens the possibility that AML factors and associated cofactors are involved in regulation of KIR expression during NK cell development.

Suppression of clonogenicity by mammalian Dnmt1 mediated by the PCNA-binding domain

Overexpression of the major DNA methyltransferase Dnmt1 is cytotoxic and has been hypothesized to result in aberrant hypermethylation of genes required for cell survival. Indeed, overexpression of mouse or human Dnmt1 in murine and human cell lines decreased clonogenicity. By frame-shift and deletion constructs, this effect of mouse Dnmt1 was localized at the N-terminal 124 amino acid domain, which mediates interaction with proliferating cell nuclear antigen (PCNA). Mutation of the PCNA-binding site restored normal cloning efficiencies. Overexpression of Dnmt3A or Dnmt3B, which do not interact with PCNA, yielded weaker effects on clonogenicity. Following introduction of the toxic domain, no significant effects on apoptosis, replication, or overall DNA methylation were observed for up to 3 d. Suppression of clonogenicity by Dnmt1 was also observed in cell lines lacking wild-type p53, p21(CIP1), or p16(INK4A). Suppression of clonogenicity by Dnmt1 overexpression may act as a fail-safe mechanism against carcinogenicity of sustained Dnmt1 overexpression.

Downregulation of CD44v6 in colorectal carcinomas is associated with hypermethylation of the CD44 promoter region

Overexpression of the cell adhesion protein CD44v6 has been demonstrated in colorectal cancer and other gastrointestinal tumors. While CD44v6 is upregulated in benign colorectal adenomas and well-differentiated colorectal cancer tissues, downregulation frequently occurs during disease progression. The mechanism of downregulation, however, is unknown. Therefore, we evaluated the methylation status of the CD44 promoter as a mechanism for decreased CD44v6 expression in advanced colorectal carcinomas. We demonstrated by methylation-sensitive restriction enzyme digestion that the CpG islands of the CD44 promoter were methylated in 6/21 (28%) of benign colorectal adenomas. Interestingly, in colorectal carcinomas the frequency of promoter methylation was significantly increased (10/19; 53%) compared to 7/21 (33%) in the corresponding normal mucosa. Methylation seems to be associated with a more advanced cancer stage, but the trend did not reach statistical significance. In colorectal carcinomas with CD44 promoter methylation CD44v6 mRNA was detected by reverse transcription-polymerase chain reaction in 3/10 carcinomas, whereas in tumors without CD44 promoter methylation CD44v6 expression was observed in 8/9 (P <or= 0.05). These results demonstrated that methylation of the 5'CpG island of the CD44 gene is closely associated with decreased expression of CD44v6 in human colorectal carcinomas.

Crucial role of DNA methylation in determination of clonally distributed killer cell Ig-like receptor expression patterns in NK cells

Human NK cells are characterized by the expression of surface receptors of the killer cell Ig-like receptor (KIR) family, which are involved in the specific recognition of pathogenic target cells. Each NK cell expresses and maintains an individual subset of inhibitory and stimulatory KIR and in this way contributes to a diversified NK cell repertoire. To date, the molecular basis for generation of clonally distributed KIR expression patterns has been elusive. Here, analyses of DNA methylation patterns of KIR genes in NK cell lines as well as in NK cells, freshly isolated from peripheral blood, demonstrated that a small CpG island surrounding the transcriptional start site of each KIR gene is consistently demethylated in expressed KIR and methylated in unexpressed KIR. DNA-demethylating treatment resulted in a rapid and stable induction of transcription and cell surface expression of all formerly unexpressed KIR in NK cell lines, NK cell clones, and freshly isolated NK cells, but not in other cell types. In vitro methylation of KIR CpG islands repressed reporter gene expression in NK cells. We conclude that clonal patterns of KIR expression are mainly epigenetically determined and maintained through DNA methylation.

Hypermethylation of the tumor necrosis factor receptor superfamily 6 (APT1, Fas, CD95/Apo-1) gene promoter at rel/nuclear factor kappaB sites in prostatic carcinoma

DNA hypermethylation of CpG-rich promoter sequences is associated with tumor suppressor gene inactivation in many human cancers, notably in carcinoma of the prostate and the urinary bladder. Recently, the mouse homologue of the tumor necrosis factor receptor superfamily 6 (TNFRSF6) gene was reported to be inactivated by DNA methylation in various cell types. The Fas (CD95, Apo-1) protein encoded by the TNFRSF6 gene is an important mediator of apoptosis, which also is downregulated in different types of human carcinoma. We therefore investigated the methylation of the TNFRSF6 promoter in prostatic and bladder carcinomas and cell lines. In a restriction enzyme polymerase chain reaction assay, four of 32 prostatic carcinomas and three of 15 advanced bladder carcinomas showed evidence of hypermethylation at the rel/nuclear factor kappaB (NFkappaB) binding sites essential for promoter activity. The DU145 cell line derived from a metastasis of a prostate carcinoma also displayed hypermethylation in this assay, which was confirmed by bisulfite sequencing. Treatment of DU145 cells with the methylation inhibitor deoxyazacytidine slightly increased Fas protein expression, as detected by flow cytometry analysis. In vitro methylation of the TNFRSF6 promoter at the rel/NFkappaB sites completely abolished its activity. Thus, although the TNFRSF6 gene can be inactivated efficiently by DNA methylation, hypermethylation occurs neither frequently nor extensively in human carcinomas and appears to play a limited role in downregulation of Fas expression.

High frequency of alterations in DNA methylation in adenocarcinoma of the prostate

BACKGROUND

Alterations of DNA methylation have been reported in many human cancers. In prostatic carcinoma, hypermethylation of the GST P gene promoter and an overall decrease in methylcytosine content have been reported. The aim of the present study was to investigate the frequency and extent of these alterations in relation to tumor stage and grade, in order to explore their clinical relevance and to determine their relationship to each other.

METHODS

DNA from 32 histologically verified adenocarcinomas of the prostate was analyzed for GST P hypermethylation by a semiquantitative PCR method and for overall DNA methylation by quantitative Southern blot analysis or LM-PCR of LINE-1 repetitive sequence methylation.

RESULTS

GST P hypermethylation was detected in 24/32 (75%) specimens, and LINE-1 hypomethylation in 17/32 (53%). Both alterations tended to increase in frequency and extent with tumor stage. All but 1 of 8 carcinomas with lymph node involvement were positive for GST P hypermethylation. Six of these as compared to 2 out of 24 showed strong hypomethylation (P = 0.005). Hypermethylation and hypomethylation did not show a quantitative correlation, but all except two samples with weak LINE-1 hypomethylation also displayed GST P hypermethylation.

CONCLUSIONS

GST P hypermethylation is an extremely frequent change in prostatic carcinoma which most probably precedes genome-wide hypomethylation. It appears useful for sensitive detection of prostatic carcinoma, whereas pronounced LINE-1 hypomethylation may be associated with progressive tumors.