Anabolic and Antiresorptive Modulation of Bone Homeostasis by the Epigenetic Modulator Sulforaphane, a Naturally Occurring Isothiocyanate.

Bone degenerative pathologies like osteoporosis may be initiated by age-related shifts in anabolic and catabolic responses that control bone homeostasis. Here we show that sulforaphane (SFN), a naturally occurring isothiocyanate, promotes osteoblast differentiation by epigenetic mechanisms. SFN enhances active DNA demethylation viaTet1andTet2and promotes preosteoblast differentiation by enhancing extracellular matrix mineralization and the expression of osteoblastic markers (Runx2,Col1a1,Bglap2,Sp7,Atf4, andAlpl). SFN decreases the expression of the osteoclast activator receptor activator of nuclear factor-κB ligand (RANKL) in osteocytes and mouse calvarial explants and preferentially induces apoptosis in preosteoclastic cells via up-regulation of theTet1/Fas/Caspase 8 and Caspase 3/7 pathway. These mechanistic effects correlate with higher bone volume (∼20%) in both normal and ovariectomized mice treated with SFN for 5 weeks compared with untreated mice as determined by microcomputed tomography. This effect is due to a higher trabecular number in these mice. Importantly, no shifts in mineral density distribution are observed upon SFN treatment as measured by quantitative backscattered electron imaging. Our data indicate that the food-derived compound SFN epigenetically stimulates osteoblast activity and diminishes osteoclast bone resorption, shifting the balance of bone homeostasis and favoring bone acquisition and/or mitigation of bone resorptionin vivo Thus, SFN is a member of a new class of epigenetic compounds that could be considered for novel strategies to counteract osteoporosis.

Statin and Bisphosphonate Induce Starvation in Fast-Growing Cancer Cell Lines.

Statins and bisphosphonates are increasingly recognized as anti-cancer drugs, especially because of their cholesterol-lowering properties. However, these drugs act differently on various types of cancers. Thus, the aim of this study was to compare the effects of statins and bisphosphonates on the metabolism (NADP⁺/NADPH-relation) of highly proliferative tumor cell lines from different origins (PC-3 prostate carcinoma, MDA-MB-231 breast cancer, U-2 OS osteosarcoma) versus cells with a slower proliferation rate like MG-63 osteosarcoma cells. Global gene expression analysis revealed that after 6 days of treatment with pharmacologic doses of the statin simvastatin and of the bisphosphonate ibandronate, simvastatin regulated more than twice as many genes as ibandronate, including many genes associated with cell cycle progression. Upregulation of starvation-markers and a reduction of metabolism and associated NADPH production, an increase in autophagy, and a concomitant downregulation of H3K27 methylation was most significant in the fast-growing cancer cell lines. This study provides possible explanations for clinical observations indicating a higher sensitivity of rapidly proliferating tumors to statins and bisphosphonates.

5-azacytidine and decitabine exert proapoptotic effects on neoplastic mast cells: role of FAS-demethylation and FAS re-expression, and synergism with FAS-ligand.

Aggressive systemic mastocytosis (ASM) and mast cell leukemia (MCL) are advanced hematopoietic neoplasms with poor prognosis. In these patients, neoplastic mast cells (MCs) are resistant against various drugs. We examined the effects of 2 demethylating agents, 5-azacytidine and decitabine on growth and survival of neoplastic MCs and the MC line HMC-1. Two HMC-1 subclones were used, HMC-1.1 lacking KIT D816V and HMC-1.2 exhibiting KIT D816V. Both agents induced apoptosis in HMC-1.1 and HMC-1.2 cells. Decitabine, but not 5-azacytidine, also produced a G(2)/M cell-cycle arrest in HMC-1 cells. Drug-induced apoptosis was accompanied by cleavage of caspase-8 and caspase-3 as well as FAS-demethylation and FAS-re-expression in neoplastic MCs. Furthermore, both demethylating agents were found to synergize with the FAS-ligand in inducing apoptosis in neoplastic MCs. Correspondingly, siRNA against FAS was found to block drug-induced expression of FAS and drug-induced apoptosis in HMC-1 cells. Neither 5-azacytidine nor decitabine induced substantial apoptosis or growth arrest in normal MCs or normal bone marrow cells. Together, 5-azacytidine and decitabine exert growth-inhibitory and proapoptotic effects in neoplastic MCs. These effects are mediated through "FAS-re-expression" and are augmented by the FAS-ligand. Whether epigenetic drugs produce antineoplastic effects in vivo in patients with ASM and MCL remains to be determined.

Vienna Cancer Stem Cell Club (VCSCC): 20 year jubilee and future perspectives.

INTRODUCTION: The Vienna Cancer Stem Cell Club (VCSCC) was launched by a group of scientists in Vienna in 2002. AREAS COVERED: Major aims of the VCSCC are to support research on cancer stem cells (CSC) in hematopoietic malignancies and to translate CSC-related markers and targets into clinical application. A primary focus of research in the VCSCC is the leukemic stem cell (LSC). Between 2013 and 2021, members of the VCSCC established a special research program on myeloproliferative neoplasms and since 2008, members of the VCSCC run the Ludwig Boltzmann Institute for Hematology and Oncology. In all these years, the VCSCC provided a robust intellectual platform for translational hematology and LSC research in Vienna. Furthermore, the VCSCC interacts with several national and international study groups and societies in the field. Representatives of the VCSCC also organized a number of international meetings and conferences on neoplastic stem cells, including LSC, in the past 15 years, and contributed to the definition and classification of CSC/LSC and related pre-malignant and malignant conditions. EXPERT OPINION: The VCSCC will continue to advance the field and to develop LSC-detecting and LSC-eradicating concepts through which diagnosis, prognostication, and therapy of blood cancer patients should improve.

Homocysteine suppresses the expression of the collagen cross-linker lysyl oxidase involving IL-6, Fli1, and epigenetic DNA methylation.

Elevated homocysteine (Hcys) serum levels represent a risk factor for several chronic pathologies, including cardiovascular disease, atherosclerosis, and chronic renal failure, and affect bone development, quality, and homeostasis. Hcys influences the formation of a stable bone matrix directly through the inhibition of the collagen cross-linking enzyme lysyl oxidase (Lox) and, as we have shown recently, by repressing its mRNA expression. The aim of this study was to investigate the mechanisms involved in this process. Through evaluation of gene arrays, quantitative RT-PCR, immunoblots, and ELISA, we identified a Hcys-dependent stimulation of interleukin 6 (IL-6) and genes involved in IL-6/Janus kinase 2 (JAK2)-dependent signal transduction pathways in pre-osteoblastic MC3T3-E1 cells. Moreover, up-regulation of genes essential for epigenetic DNA methylation (DNA (cytosine-5)-methyltransferases and helicase lymphoid-specific (Hells) was observed. Further investigations demonstrated that Hcys increased via IL-6/JAK2 the expression of Fli1 (Friend leukemia virus integration 1), a transcription factor, which we found essential for IL-6-dependent Dnmt1 stimulation. CpG methylation analysis of CpG-rich Lox proximal promoter revealed an increased CpG methylation status after treatment of the cells with Hcys indicating an epigenetic origin for Hcys-dependent Lox repression. Inhibition of the IL-6/JAK2 pathway or of CpG methylation reversed the repressive effect of Hcys on Lox expression. In conclusion, we demonstrate that Hcys stimulates IL-6 synthesis in osteoblasts, which is known to affect bone metabolism via osteoclasts. Furthermore, IL-6 stimulation results via JAK2, Fli1, and Dnmt1 in down-regulation of Lox expression by epigenetic CpG methylation revealing a new mechanism negatively affecting bone matrix formation.

Extra-cellular matrix suppresses expression of the apoptosis mediator Fas by epigenetic DNA methylation.

The extracellular matrix (ECM) of bone consists mainly of collagen type I, which induces osteoblastic differentiation and prevents apoptosis. Fas induces apoptosis in cells improperly adhering to ECM. Recently, it was described that Fas expression is modulated by epigenetic DNA methylation. Mouse MC3T3-E1 pre-osteoblastic cells were cultured either on collagen coated or on uncoated culture dishes for control. mRNA was isolated and gene expression was analyzed by quantitative RT-PCR. Furthermore, we measured global and specific DNA methylation. Compared to controls, cells cultured on collagen-coated dishes increased the expression of Runx2 and OCN indicating differentiation of pre-osteoblastic cells. Additionally, collagen up-regulated cyclin-A2 and down-regulated Fas expression suggesting increased cell multiplication. Furthermore, the expression of Dnmt1 and Hells, key mediators of the DNA-methylation process, was increased. As a consequence, we demonstrate that global DNA methylation and specific methylation of the Fas promoter was higher in MC3T3-E1 cells cultured on collagen when compared to controls. Investigation of signal transduction pathways by mean of inhibitors suggests that focal adhesion kinase, MAP- and Jun-kinases and AP-1 are involved in this process. In summary, we demonstrate that ECM prevents activation of Fas by epigenetic DNA-methylation.

Breaking bad news to cancer patients: survey and analysis.

PURPOSE: To find out how patients perceived the disclosure of news about their cancer as regards the physician counselling and how they perceived the flow of information between hospital-based and family physicians. METHODS: 272 cancer patients were polled with a 16-item questionnaire. RESULTS: 252 cancer patients, 92.6% of those asked, completed the questionnaire. 37.7% (f:35.4%, m:41.8%) stated that the fact that they had cancer was presented to them 'very empathically' or 'empathically'. 62.3% (f:64.7%, m:58.3%) stated that it was presented to them 'not so empathically' or ' not at all empathically'. When patients had been counselled by family physicians they were more likely to state that it had been done 'very empathically' or 'empathically', in contrast to when they had been counselled by hospital-oncologists or self-employed specialists (81.8% vs. 41.2% vs. 41.2%; p=0.001). Significantly more patients thought that they had been given adequate opportunity to ask the questions they considered important when counselled by a family physician (81.8%) as compared to counselling by a hospital-oncologist (43.5%; p=0.002) or a self-employed specialist (44.3%; p=0.001). 56.8% preferred to discuss the suggested cancer therapies with an oncologist. 87.5% of patients considered the exchange of information between the hospital-based specialists and their family physician 'very important' or 'important'; more than half of all patients stated that this exchange of information was 'rather poor' or 'poor'. CONCLUSIONS: Oncologists should involve family physicians in disclosing bad news to patients. There are considerable deficiencies regarding information-exchange in cancer care in Austria.

Epigenetic regulation of human buccal mucosa mitochondrial superoxide dismutase gene expression by diet.

The impact of nutrition on the epigenetic machinery has increasingly attracted interest. The aim of the present study was to demonstrate the effects of various diets on methylation and gene expression. The antioxidative enzyme mitochondrial superoxide dismutase (MnSOD) was chosen as the model system because epigenetic regulation has been previously shown in cell lines for this gene. Promoter methylation and gene expression of MnSOD in buccal swabs from three sample groups were analysed. The three groups included: (1) forty vegetarians (aged 20-30 years); (2) age-matched omnivores; (3) elderly omnivores (aged>85 years). A 3-fold increase in the expression of the MnSOD gene was associated with decreased CpG methylation of the analysed promoter region in the vegetarian group compared with the age-matched omnivores group. Expression and promoter methylation of the MnSOD gene in elderly omnivores showed no significant differences compared with younger omnivores. In accordance with previous findings in various tissues, DNA global methylation was found to be significantly higher (30 %) in buccal swabs of younger subjects (independent of the diet), than in those of elderly omnivores. In the control experiment which was designed to verify the findings of the human buccal swab studies, the Caco-2 cell line was treated with zebularine. Results of the control study showed a 6-fold increase of MnSOD expression, an approximately 40 % decreased methylation of specified CpG in the MnSOD promoter and a 50 % reduction of global DNA methylation. These results indicate that diet affects the epigenetic regulation of human MnSOD.

Osteocalcin attenuates T3- and increases vitamin D3-induced expression of MMP-13 in mouse osteoblasts.

Osteocalcin (OCN), the most abundant non-collagenous protein of the bone matrix, whose function is not fully understood, was recently suggested to act as endocrine factor regulating energy metabolism. Besides OCN, osteoblasts also express MMP-13, a matrix metallo-proteinase important for bone development and remodeling. Although differentially, both genes are regulated by 1,25-dihydroxy vitamin D3 (1,25D3) and T3, important hormones for bone metabolism. In mouse osteoblasts with a distinct differentiation status, T3 increases the expression of both proteins. By contrast, 1,25D3 stimulates the expression of MMP-13 but inhibits the expression of OCN in these cells. In humans, however, 1,25D3 upregulates both genes while T3 inhibits the OCN expression. Using northern blot hybridization we studied gene expression in the mouse osteoblastic cell line MC3T3-E1. We show that MMP-13 expression was strongly increased by T3 when the stimulation of OCN was low and, inversely, that the MMP-13 increase was low when T3 strongly stimulated the OCN expression. These findings suggest an interrelationship between OCN and MMP-13 expression. In fact, we observed that externally added OCN attenuated the T3 induced MMP-13 expression dose dependently and, furthermore, increased the 1,25D3 stimulated MMP-13 expression. Using a protein kinase A inhibitor we were able to show that this inhibitor mimics the effect of OCN suggesting a PKA dependent pathway to be involved in this regulatory process. We therefore hypothesize that OCN is a modulator of the hormonally regulated MMP-13 expression.

Imatinib mesylate (IM)-induced growth inhibition is associated with production of spliced osteocalcin-mRNA in cell lines.

It has been suggested that imatinib mesylate (IM) influences osteogenesis and bone turnover in treated patients. Here we show that the inhibitory effect of IM on cell multiplication is associated with an increased proportion of spliced osteocalcin (OCNs) in leukemia (HL-60) and osteosarcoma cells (MG-63, U-2 OS), despite a lower mRNA synthesis rate. In mouse osteoblastic MC3T3-E1 cells only OCNs is present, independently of treatment. As the stimulatory effect of IM on OCNs is also observed upon treatment with vitamin D, common regulatory processes may be considered.

Vegetarian diet affects genes of oxidative metabolism and collagen synthesis.

BACKGROUND/AIM: A vegetarian diet is known to prevent a series of diseases but may influence the balance of carbohydrate and fat metabolism as well as collagen synthesis. This study compares expression patterns of relevant genes in oral mucosa of omnivores and vegetarians. METHODS: Quantitative reverse transcriptase polymerase chain reaction was applied for analysis of mRNA levels from carnitine transporter OCTN2, hepatic CPT1A and nonhepatic CPT1B isoforms of carnitine palmitoyltransferase and collagen (CCOL2A1) in oral mucosa. RESULTS: Compared with volunteers with traditional eating habits, carbohydrate consumption was significantly higher (+22%) in vegetarians. This was associated with a significant stimulation of CPT1A (+50%) and OCTN2 (+10%) and a lowered collagen synthesis (-10%). CONCLUSION: These novel findings provide further insight into the association of a changed fat metabolism and reduced collagen synthesis in vegetarians, which could also play a role in the aging process.

Ludwig Boltzmann Cluster Oncology (LBC ONC): first 10 years and future perspectives.

In 2008 the Ludwig Boltzmann Cluster Oncology (LBC ONC) was established on the basis of two previous Ludwig Boltzmann Institutes working in the field of hematology and cancer research. The general aim of the LBC ONC is to improve treatment of hematopoietic neoplasms by eradicating cancer-initiating and disease-propagating cells, also known as leukemic stem cells (LSC) in the context of leukemia. In a first phase, the LBC ONC characterized the phenotype and molecular aberration profiles of LSC in various malignancies. The LSC phenotypes were established in acute and chronic myeloid leukemia, in acute lymphoblastic leukemia and in chronic lymphocytic leukemia. In addition, the concept of preleukemic (premalignant) neoplastic stem cells (pre-L-NSC) was coined by the LBC ONC and was tested in myelodysplastic syndromes and myeloproliferative neoplasms. Phenotypic characterization of LSC provided a solid basis for their purification and for the characterization of specific target expression profiles. In a second phase, molecular markers and targets were validated. This second phase is ongoing and should result in the development of new diagnostics parameters and novel, more effective, LSC-eradicating, treatment strategies; however, many issues still remain to be solved, such as sub-clonal evolution, LSC niche interactions, immunologic control of LSC, and LSC resistance. In the forthcoming years, the LBC ONC will concentrate on developing LSC-eradicating strategies, with special focus on LSC resistance, precision medicine and translation of LSC-eradicating concepts into clinical application.

Myelodysplastic syndromes, aging, and age: correlations, common mechanisms, and clinical implications.

Myelodysplastic syndromes (MDS) are a heterogenous group of myeloid neoplasms that develop primarily in elderly patients. Although a specific molecular basis for the predominant incidence of MDS in higher age groups remains unknown, several lines of evidence suggest that the biology of aging and the pathogenesis of MDS share several genetic, epigenetic, and molecular features. The current review attempts to delineate these common aspects as well as additional discriminative features that are specific for MDS and thus help explaining disease-evolution and progression. In addition, the present review discusses age as an important prognostic factor and co-variable to be considered in treatment algorithms in MDS.

Expression and functional significance of osteocalcin splicing in disease progression of hematological malignancies.

The aim of this study was to investigate the expression of osteocalcin (OCN) splicing variants in hematological malignancies. We analysed bone marrow obtained from two patients with chronic myeloid leukemia (CML), seven patients with other myeloproliferative diseases (MPD) and four patients with acute myeloid leukemia (AML). RT-PCR analyses were performed in order to assess and quantify spliced (OCNs) and unspliced (OCNu) mRNA, the associated transcription factors (AML1 and AML3) as well as c-KIT which is a marker for activated stem cells. Our data indicate that OCNs mRNA and OCN protein is expressed in c-KIT positive neoplastic stem cells in hematological malignancies.

Effects of doxorubicin-containing chemotherapy and a combination with L-carnitine on oxidative metabolism in patients with non-Hodgkin lymphoma.

PURPOSE: Chemotherapy regimens based on anthracycline (doxorubicin) are well established in lymphoma therapy. The purpose of this study was to examine the effects of L-carnitine with a view to reducing cytotoxic side-effects. METHODS: 20 patients were scheduled to receive 3 g L-carnitine before each chemotherapy cycle, followed by 1 g L-carnitine/day during the following 21 days, while 20 patients received a placebo (randomized controlled trial). The plasma lipid profile and relative mRNA levels of key enzymes of oxidative metabolism (carnitine acyltransferases) were measured at three points of time. In addition to the clinical parameters we used the mRNA of white blood cells to evaluate the toxic effects on cardiomyocytes. RESULTS: In the present study no cardiotoxicity of anthracycline therapy was detected. Carnitine treated patients showed a rise in plasma carnitine which led to an increase of relative mRNA levels from CPT1A (liver isoform of carnitine palmitoyltransferase) and OCTN2 (carnitine transporter). Following chemotherapy, an activation of carnitine acyltransferases was associated with a stimulation of OCTN2 in both groups. CONCLUSION: Biochemical and molecular analyses indicated a stimulation of oxidative metabolism in white blood cells through carnitine uptake.

Downregulation of carnitine acyltransferases and organic cation transporter OCTN2 in mononuclear cells in healthy elderly and patients with myelodysplastic syndromes.

Changes in key enzymes of oxidative metabolism at the mitochondrial level are known to be associated with the aging process, apoptosis, and many diseases. Considering the risk of acquiring a myelodysplastic syndrome (MDS) with age, the aim of this study was to quantify mRNA synthesis of the carnitine palmitoyltransferases (CPT1 and CPT2), carnitine acetyltransferase (CRAT), human specific microsomal CPT, and OCTN2 (organic cation transporter) in mononuclear cells of healthy humans of different age groups and MDS patients. Using quantitative reverse transcriptase real-time PCR we compared mRNA synthesis of the above mentioned enzymes in mononuclear cells from peripheral blood of 23 healthy persons (mean age 45 years), 9 blood and 22 bone marrow samples of 31 MDS patients with varying proportions of apoptotic cells (mean age 78 years), and blood samples of 30 age-matched controls. In addition, plasma carnitine levels were determined. Compared to younger adults, there was a 50% downregulation of CPT1 in elderly persons and in MDS patients. Reduction in CRAT, CPT 2, and OCTN2 was more than 85%. Reduction in microsomal CPT was more pronounced in MDS patients than in age-matched controls (96% vs. 43%). In MDS bone marrow cells there was a negative correlation of CPT1 and CRAT with the relative proportion of apoptotic cells. Plasma carnitine values were similar in all groups. The described reduction in transcription of different genes in blood cells which is well known in different tissues may reflect a systemic signaling process, associated with aging, apoptosis, and MDS.

Inhibition of the mevalonate pathway affects epigenetic regulation in cancer cells.

The mevalonate pathway provides metabolites for post-translational modifications such as farnesylation, which are critical for the activity of RAS downstream signaling. Subsequently occurring regulatory processes can induce an aberrant stimulation of DNA methyltransferase (DNMT1) as well as changes in histone deacetylases (HDACs) and microRNAs in many cancer cell lines. Inhibitors of the mevalonate pathway are increasingly recognized as anticancer drugs. Extensive evidence indicates an intense cross-talk between signaling pathways, which affect growth, differentiation, and apoptosis either directly or indirectly via epigenetic mechanisms. Herein, we show data obtained by novel transcriptomic and corresponding methylomic or proteomic analyses from cell lines treated with pharmacologic doses of respective inhibitors (i.e., simvastatin, ibandronate). Metabolic pathways and their epigenetic consequences appear to be affected by a changed concentration of NADPH. Moreover, since the mevalonate metabolism is part of a signaling network, including vitamin D metabolism or fatty acid synthesis, the epigenetic activity of associated pathways is also presented. This emphasizes the far-reaching epigenetic impact of metabolic therapies on cancer cells and provides some explanation for clinical observations, which indicate the anticancer activity of statins and bisphosphonates.

Dietary l-carnitine stimulates carnitine acyltransferases in the liver of aged rats.

Aging affects oxidative metabolism in liver and other tissues. Carnitine acyltransferases are key enzymes of this process in mitochondria. As previously shown, the rate of transcription and activity of carnitine palmitoyltransferase CPT1 are also related to carnitine levels. In this study we compared the effect of dietary l-carnitine (100 mg l-carnitine/kg body weight/day over 3 months) on liver enzymes of aged rats (months 21-24) to adult animals (months 6-9) and age-related controls for both groups. The transcription rate of CPT1, CPT2, and carnitine acetyltransferase (CRAT) was determined by quantitative reverse transcription real-time PCR (RTQPCR) and compared to the activity of the CPT1A enzyme. The results showed that the transcription rates of CPT1, CPT2, and CRAT were similar in aged and adult control animals. Carnitine-fed old rats had a significant (p<0.05) 8-12-fold higher mean transcription rate of CPT1 and CRAT compared to aged controls, adult carnitine-fed animals, and adult controls, whereas the transcription rate of CPT2 was stimulated 2-3-fold in carnitine-fed animals of both age groups. With regard to the enzymatic activity of CPT1 there was a 1.5-fold increase in the old carnitine group compared to all other groups. RNA in situ hybridization also indicated an enhanced expression of CPT1A in hepatocytes from l-carnitine-supplemented animals. These results suggest that l-carnitine stimulates transcription of CPT1, CPT2, and CRAT as well as the enzyme activity of CPT1 in the livers of aged rats.

Supplementation of L-carnitine in athletes: does it make sense?

Studies in athletes have shown that carnitine supplementation may foster exercise performance. As reported in the majority of studies, an increase in maximal oxygen consumption and a lowering of the respiratory quotient indicate that dietary carnitine has the potential to stimulate lipid metabolism. Treatment with L-carnitine also has been shown to induce a significant postexercise decrease in plasma lactate, which is formed and used continuously under fully aerobic conditions. Data from preliminary studies have indicated that L-carnitine supplementation can attenuate the deleterious effects of hypoxic training and speed up recovery from exercise stress. Recent data have indicated that L-carnitine plays a decisive role in the prevention of cellular damage and favorably affects recovery from exercise stress. Uptake of L-carnitine by blood cells may induce at least three mechanisms: 1) stimulation of hematopoiesis, 2) a dose-dependent inhibition of collagen-induced platelet aggregation, and 3) the prevention of programmed cell death in immune cells. As recently shown, carnitine has direct effects in regulation of gene expression (i.e., carnitine-acyltransferases) and may also exert effects via modulating intracellular fatty acid concentration. Thus there is evidence for a beneficial effect of L-carnitine supplementation in training, competition, and recovery from strenuous exercise and in regenerative athletics.

The role of epigenetics in the regulation of apoptosis in myelodysplastic syndromes and acute myeloid leukemia.

Disordered stem cell epigenetics and apoptosis-regulating mechanisms contribute essentially to the pathogenesis of myelodysplastic syndromes (MDS) and may trigger disease-progression to secondary acute myeloid leukemia (AML). Expression of apoptosis-mediators FAS (CD95) and DAPK1 the latter being also known for its association with autophagy are upregulated in neoplastic cells in patients with low-risk MDS and epigenetically silenced and downregulated in high-risk MDS and AML as confirmed by a study 50 MDS and 30 AMLs complementing this review. 5-Azacytidine (AZA) and 5-aza-2'deoxycytidine (DAC), promoted FAS and DAPK1 gene demethylation and their (re)expression as well as apoptosis in leukemic cell lines (HL-60, KG1) which can be reversed by siRNA against FAS. Thus, promoter-demethylation of FAS and DAPK1 represents a critical mechanism of drug-induced apoptosis in neoplastic cells in MDS and AML which underscores the clinical implication of epigenetically active therapies.