Expression profiling of extramedullary acute myeloid leukemia suggests involvement of epithelial-mesenchymal transition pathways.

Extramedullary (EM) colonization is a rare complication of acute myeloid leukemia (AML), occurring in about 10% of patients, but the processes underlying tissue invasion are not entirely characterized. Through the application of RNAseq technology, we examined the transcriptome profile of 13 AMLs, 9 of whom presented an EM localization. Our analysis revealed significant deregulation within the extracellular matrix (ECM)-receptor interaction and focal-adhesion pathways, specifically in the EM sites. The transcription factor TWIST1, which is known to impact on cancer invasion by dysregulating epithelial-mesenchymal-transition (EMT) processes, was significantly upregulated in EM-AML. To test the functional impact of TWIST1 overexpression, we treated OCI-AML3s with TWIST1-siRNA or metformin, a drug known to inhibit tumor progression in cancer models. After 48 h, we showed downregulation of TWIST1, and of the EMT-related genes FN1 and SNAI2. This was associated with significant impairment of migration and invasion processes by Boyden chamber assays. Our study shed light on the molecular mechanisms associated with EM tissue invasion in AML, and on the ability of metformin to interfere with key players of this process. TWIST1 may configure as candidate marker of EM-AML progression, and inhibition of EMT-pathways may represent an innovative therapeutic intervention to prevent or treat this complication.

Bone Marrow Microenvironment Involvement in t-MN: Focus on Mesenchymal Stem Cells.

Therapy-related myeloid neoplasms (t-MN) are a late complication of cytotoxic therapy (CT) used in the treatment of both malignant and non-malignant diseases. Historically, t-MN has been considered to be a direct consequence of DNA damage induced in normal hematopoietic stem or progenitor cells (HSPC) by CT. However, we now know that treatment-induced mutations in HSC are not the only players involved in t-MN development, but additional factors may contribute to the onset of t-MN. One of the known drivers involved in this field is the bone marrow microenvironment (BMM) and, in particular, bone marrow mesenchymal stem cells (BM-MSC), whose role in t-MN pathogenesis is the topic of this mini-review. BM-MSCs, physiologically, support HSC maintenance, self-renewal, and differentiation through hematopoietic-stromal interactions and the production of cytokines. In addition, BM-MSCs maintain the stability of the BM immune microenvironment and reduce the damage caused to HSC by stress stimuli. In the t-MN context, chemo/radiotherapy may induce damage to the BM-MSC and likewise alter BM-MSC functions by promoting pro-inflammatory response, clonal selection and/or the production of factors that may favor malignant hematopoiesis. Over the last decade, it has been shown that BM-MSC isolated from patients with de novo and therapy-related MN exhibit decreased proliferative and clonogenic capacity, altered morphology, increased senescence, defective osteogenic differentiation potential, impaired immune-regulatory properties, and reduced ability to support HSC growth and differentiation, as compared to normal BM-MSC. Although the understanding of the genetic and gene expression profile associated with ex vivo-expanded t-MN-MSCs remains limited and debatable, its potential role in prognostic and therapeutic terms is acting as a flywheel of attraction for many researchers.

Regulatory mechanisms of the early phase of white adipocyte differentiation: an overview.

The adipose organ comprises two main fat depots termed white and brown adipose tissues. Adipogenesis is a process leading to newly differentiated adipocytes starting from precursor cells, which requires the contribution of many cellular activities at the genome, transcriptome, proteome, and metabolome levels. The adipogenic program is accomplished through two sequential phases; the first includes events favoring the commitment of adipose tissue stem cells/precursors to preadipocytes, while the second involves mechanisms that allow the achievement of full adipocyte differentiation. While there is a very large literature about the mechanisms involved in terminal adipogenesis, little is known about the first stage of this process. Growing interest in this field is due to the recent identification of adipose tissue precursors, which include a heterogenous cell population within different types of adipose tissue as well as within the same fat depot. In addition, the alteration of the heterogeneity of adipose tissue stem cells and of the mechanisms involved in their commitment have been linked to adipose tissue development defects and hence to the onset/progression of metabolic diseases, such as obesity. For this reason, the characterization of early adipogenic events is crucial to understand the etiology and the evolution of adipogenesis-related pathologies, and to explore the adipose tissue precursors' potential as future tools for precision medicine.

Absence of FGFR3-TACC3 rearrangement in hematological malignancies with numerical chromosomal alteration.

FGFR-TACC, found in different tumor types, is characterized by the fusion of a member of fibroblast grown factor receptor (FGFR) tyrosine kinase (TK) family to a member of the transforming acidic coiled-coil (TACC) proteins. Because chromosome numerical alterations, hallmarks of FGFR-TACC fusions are present in many hematological disorders and there are no data on the prevalence, we studied a series of patients with acute myeloid leukemia and myelodysplastic syndrome who presented numerical alterations using cytogenetic traditional analysis. None of the analyzed samples showed FGFR3-TACC3 gene fusion, so screening for this mutation at diagnosis is not recommended.

MTHFR, TS and XRCC1 genetic variants may affect survival in patients with myelodysplastic syndromes treated with supportive care or azacitidine.

We evaluated the impact of genomic polymorphisms in folate-metabolizing, DNA synthesis and DNA repair enzymes on the clinical outcome of 108 patients with myelodysplastic syndromes (MDS) receiving best supportive care (BSC) or azacitidine. A statistically significant association between methylenetetrahydrofolate reductase (MTHFR) 677T/T, thymidylate synthase (TS) 5'-untranslated region (UTR) 3RG, TS 3'-UTR -6 bp/-6 bp, XRCC1 399G/G genotypes and short survival was found in patients receiving BSC by multivariate analysis (P<0.001; P=0.026; P=0.058; P=0.024). MTHFR 677T/T, TS 3'-UTR -6 bp/-6 bp and XRCC1 399G/G genotypes were associated with short survival in patients receiving azacitidine by multivariate analysis (P<0.001; P=0.004; P=0.002). We then performed an exploratory analysis to evaluate the effect of the simultaneous presence of multiple adverse variant genotypes. Interestingly, patients with ⩾1 adverse genetic variants had a short survival, independently from their International Prognostic Scoring System (IPSS) and therapy received. To our knowledge, this is the first study showing that polymorphisms in folate-metabolizing pathway, DNA synthesis and DNA repair genes could influence survival of MDS patients.

Attenuation of diet-induced obesity and induction of white fat browning with a chemical inhibitor of histone deacetylases.

BACKGROUND/OBJECTIVES: In the last decade, a strict link between epigenetics and metabolism has been demonstrated. Histone deacetylases (HDACs) have emerged as key epigenetic regulators involved in metabolic homeostasis in normal and pathologic conditions. Here we investigated the effect of the class I HDAC inhibitor MS-275 in a model of obesity induced by a high-fat diet (HFD). METHODS: C57BL6/J male mice were fed HFD for 17 weeks and then randomized in two groups, treated intraperitoneally with vehicle dimethylsulfoxide (DMSO) or with the class I selective HDAC inhibitor MS-275 every other day for 22 days. Glucose tolerance test and measurement of body temperature during cold exposure were performed. Adipose tissues and liver were phenotypically characterized through histological analysis. Gene and protein expression analysis of brown and white adipose tissues (WATs) were performed. RESULTS: MS-275 treated mice showed 10% reduction of body weight, lower adipocyte size and improved glucose tolerance. Inhibition of class I HDAC determined reduction of adipocyte size and of fat mass, paralleled by higher expression of adipose functionality markers and by increased rate of lipolysis and fatty acid ß-oxidation. MS-275 also promoted thermogenic capacity, related to 'browning' of visceral and subcutaneous WAT, showing increased expression of uncoupling protein 1. In brown adipose tissue, we observed limited effects on gene expression and only reduction of brown adipocyte size. CONCLUSIONS: This study provides evidence that class I HDAC inhibition stimulated functionality and oxidative potential of adipose tissue, improving glucose tolerance and ameliorating the metabolic profile in diet-induced obese mice.

Total thyroidectomy for Graves' disease treatment.

OBJECTIVES: Graves' disease (GD) is the most common cause of hyperthyroidism, and accounts worldwide for 60-80% of all cases. The diagnosis is based on clinical findings, and is confirmed by the presence of TRAB, suppression of TSH, and elevation of free thyroxin (free T4), and triiodinethyronin (free T3). GD can be treated by antithyroid drugs, radioactive iodine, or surgery. The aim of this study was to review retrospectively the surgical management, in terms of safety and efficacy, in 50 patients operated in the Department of Surgical Sciences since 2005 through 2010 and followed up at the Endocrinology Unit A of the Experimental Medicine Department. We assessed postoperative complications, which included the presence, persistence and development of ophthalmopathy, transient hypocalcemia, permanent hypoparathyroidism and recurrent laryngeal nerve palsy. MATERIALS AND METHODS: We analyzed data from 50 patients with GD who were eligible and underwent Total Thyroidectomy (TT). Thirty-nine patients underwent TT for recurrent hyperthyroidism after medical therapy and eleven patients for severe ophtalmopathy. The mean follow up was 41 months (range: 10-70). RESULTS: Eleven patients had ophtalmopathy before surgery. Four patients developed an ophtalmopathy after surgery. Eleven patients presented hypocalcemia, transient in ten patients and permanent in one patient. Five patients developed a transient disphony. Conclusions. Total thyroidectomy is a safe and radical procedure in Graves' disease treatment. Complications of TT are not different than subtotal thyroidectomy if it's performed by expert surgeons.

5-azacytidine in chronic myelomonocytic leukemia: case report and review of literature.

Hypomethylating drugs are useful in the management of Myelodysplastic syndromes, but there are only few reports on chronic myelomonocycitic (CMML) leukemia patients. We describe our experience in 3 CMML patients treated with azacitidine. Two patients obtained partial response after 4 treatment cycles with only minor toxicity and are in continuous partial response, with stable peripheral blood counts, at 29 and 30 cycles from treatment start.

Expression of sterol 27-hydroxylase in glial cells and its regulation by liver X receptor signaling.

Cholesterol is required in the brain for synaptogenesis and its turnover is critical for cerebral functions. Several proteins involved in cholesterol handling and metabolism are transcriptionally regulated by the nuclear liver X receptor (LXR) alpha and beta. Sterol 27-hydroxylase (CYP27) is a ubiquitously expressed enzyme involved in cholesterol metabolism. Notably, its deficiency causes a disease characterized by progressive neurologic impairment. With the final goal to understand the pathophysiological role of CYP27A1 in the CNS, we studied the expression pattern of Cyp27a1 and other related genes in primary cultures of rat glia and neurons. Secondly, given the pivotal role of LXR in the regulation of cholesterol homeostasis, we investigated the effects of its activation on the expression of Cyp27a1.We found that primary astrocytes express different sterol hydroxylases and are able to uptake exogenous 27-hydroxycholesterol. We found that both microglia and astrocytes express preferentially Lxrbeta. However, despite this similarity, we observed cell-specific responsiveness of known and novel (including Cyp27a1) target genes to LXR activation. The increase of mRNA and protein levels in treated astrocytes is paralleled by transactivation of the proximal Cyp27a1 promoter in transfected astrocytes. We suggest that the astrocyte-restricted up-regulation of Cyp27a1 may be ascribable to differential expression of transcriptional co-activators. Given the role of astrocytes in maintaining brain homeostasis, we hypothesize that impairment of CYP27 activity in these cells may alter critical features of the astrocytes, from the handling and delivery of cholesterol to neurons to the release of signaling molecules.

Dynamics of apomyoglobin in the alpha-to-beta transition and of partially unfolded aggregated protein.

Changes of molecular dynamics in the alpha-to-beta transition associated with amyloid fibril formation were explored on apomyoglobin (ApoMb) as a model system. Circular dichroism, neutron and X-ray scattering experiments were performed as a function of temperature on the protein, at different solvent conditions. A significant change in molecular dynamics was observed at the alpha-to-beta transition at about 55 degrees C, indicating a more resilient high temperature beta structure phase. A similar effect at approximately the same temperature was observed in holo-myoglobin, associated with partial unfolding and protein aggregation. A study in a wide temperature range between 20 and 360 K revealed that a dynamical transition at about 200 K for motions in the 50 ps time scale exists also for a hydrated powder of heat-denatured aggregated ApoMb.

Neutron scattering study of the vibrations in vitreous silica and germania.

The incoherent approximation for the determination of the vibrational density of states of glasses from inelastic neutron or x-ray scattering data is extended to treat the coherent scattering. The method is applied to new room temperature measurements of vitreous silica and germania on the thermal time-of-flight spectrometer IN4 at the High Flux Reactor in Grenoble. The inelastic dynamic structure factor at the boson peak turns out to agree reasonably well with simulation results, but the long-wavelength fraction exceeds the expectation of the Debye model, in particular, in germania.

Prognostic role of glutathione S-transferase polymorphisms in acute myeloid leukemia.

Glutathione S-transferases (GSTs) are phase II detoxification enzymes involved in the metabolism of carcinogens and anticancer drugs, known also to interact with kinase complexes during oxidative or chemical stress-induced apoptosis. We were interested whether their polymorphic variants may account for differences in outcome of patients with acute myeloid leukemia (AML) following chemotherapy. We studied the prognostic role of polymorphisms in three GST genes (GSTP1/M1/T1) in a large patient cohort of the German Austrian Acute Myeloid Leukemia Study Group, treated according to prospective multicenter clinical trials (AML HD98A: 254 patients; AML HD98-B: 100 patients), with a median follow-up of 46 months. Looking at short-term adverse drug reactions, homozygous carriers of the GSTP1*105 Val allele had a faster neutrophil and platelet recovery (P=0.002 and 0.02, respectively) and a reduced need of red cell and platelet transfusions (P=0.01 and 0.03, respectively). Response to induction chemotherapy did not vary according to GST polymorphisms. Multivariable Cox regression models revealed a significant better relapse-free (RFS) and overall survival for the GSTP1(*)105 Val (P=0.003 and 0.03, respectively), whereas GSTT1 and GSTM1 genotypes had no significant impact. The favorable impact of GSTP1(*)105 Val on RFS seems to be restricted to the subgroup of patients exhibiting a normal karyotype.

Bile acids and their signaling pathways: eclectic regulators of diverse cellular functions.

The field of bile acids has witnessed an impulse in the last two decades. This has been the result of cloning the genes encoding enzymes of bile acid synthesis and their transporters. There is no doubt that the identification of Farnesoid X Receptor (FXR, NR1H4) as the bile acid receptor has contributed substantially to attract the interest of scientists in this area. When FXR was cloned by Forman et al. [1], farnesol metabolites were initially considered the physiological ligands. After identifying FXR and other nuclear receptors as bile acid sensors [2-4], it has become clear that bile acids are involved in the regulation of lipid and glucose metabolism and that these molecules are eclectic regulators of diverse cellular functions. In this review, we will summarize the current knowledge of the functions regulated by bile acids and how their physiological receptors mediate the signaling underlying numerous cellular responses.

Increased risk of acute myeloid leukaemia due to polymorphisms in detoxification and DNA repair enzymes.

BACKGROUND: Polymorphisms in genes involved in detoxification and DNA-repair pathways may modify the individual's risk for genomic damage, and, as a consequence, the risk of developing malignant diseases. PATIENTS AND METHODS: We performed a case-control study including 160 cases of acute myeloid leukaemia (AML) and 162 matched controls to test the impact of six genomic polymorphisms on the risk to develop AML and/or therapy-related AML. RESULTS: We found a significantly higher prevalence of the polymorphic variants RAD51-G135C and CYP3A4-A-290G genes in AML cases, when compared with controls (P = 0.02 and P = 0.04), increasing the risk of AML 2.1-folds (95% CI: 1.1-4.0) and 3.2-fold (95% CI: 1.1-11.5), respectively. Carriers of both the RAD51-G135C and CYP3A4-A-290G variants were at highest AML risk (P = 0.003; OR:13,6; 95% CI: 2.0-585.5), suggesting a synergistic effect between these polymorphisms. CONCLUSIONS: These results suggest that polymorphic variants in DNA-repair and detoxification enzymes may co-operate in modulating the individual's risk of AML.

Age-related changes in bile acid synthesis and hepatic nuclear receptor expression.

BACKGROUND: Recent data highlighted the role of nuclear receptors in the transcriptional regulation of the limiting enzyme of bile acid synthesis, cholesterol 7alpha-hydroxylase, in cellular and animal models. This study was designed to analyze the effects of age on cholesterol 7alpha-hydroxylase and related nuclear receptor expression in human livers. DESIGN: Surgical liver biopsies were obtained in 23 patients requiring operation on the gastrointestinal tract. mRNA levels of cholesterol 7alpha-hydroxylase and related nuclear receptors and co-activators were assayed by quantitative real-time RT-PCR. Serum levels of 7alpha-hydroxy-4-cholesten-3-one, a marker of bile acid synthesis, were assayed by gas-liquid chromatography:mass spectrometry. RESULTS: Ageing was inversely correlated with serum 7alpha-hydroxy-4-cholesten-3-one and with cholesterol 7alpha-hydroxylase mRNA levels (r = -0.44 and r = -0.45 on a semi-log scale, respectively, P < 0.05). Among different nuclear factors, cholesterol 7alpha-hydroxylase mRNA best correlated with hepatocyte nuclear factor-4 (r = 0.55 on a log scale, P < 0.05); hepatocyte nuclear factor-4 levels were also inversely correlated with age (r = -0.64 on a semi-log scale, P < 0.05). Age was inversely correlated with serum insulin-like growth factor-I levels, which were directly correlated with hepatocyte nuclear factor-4 and cholesterol 7alpha-hydroxylase expression. No suppressive effect of short heterodimer partner expression on cholesterol 7alpha-hydroxylase was observed. CONCLUSIONS: Ageing associates with reduced bile acid synthesis, possibly related to decreased hepatic expression of hepatocyte nuclear factor-4 and consequently of cholesterol 7alpha-hydroxylase. Age-related modifications of the growth hormone/insulin-like growth factor axis might play a role. These findings may help to elucidate the pathophysiology of age-related modifications of cholesterol metabolism.

Reduced BRCA1 expression due to promoter hypermethylation in therapy-related acute myeloid leukaemia.

BRCA1 plays a pivotal role in the repair of DNA damage, especially following chemotherapy and ionising radiation. We were interested in the regulation of BRCA1 expression in acute myeloid leukaemia (AML), in particular in therapy-related forms (t-AML). Using real-time PCR and Western blot, we found that BRCA1 mRNA was expressed at barely detectable levels by normal peripheral blood granulocytes, monocytes and lymphocytes, whereas control BM-mononuclear cells and selected CD34+ progenitor cells displayed significantly higher BRCA1 expression (P=0.0003). Acute myeloid leukaemia samples showed heterogeneous BRCA1 mRNA levels, which were lower than those of normal bone marrows (P=0.0001). We found a high frequency of hypermethylation of the BRCA1 promoter region in AML (51/133 samples, 38%), in particular in patients with karyotypic aberrations (P=0.026), and in t-AML, as compared to de novo AML (76 vs 31%, P=0.0002). Examining eight primary tumour samples from hypermethylated t-AML patients, BRCA1 was hypermethylated in three of four breast cancer samples, whereas it was unmethylated in the other four tumours. BRCA1 hypermethylation correlated to reduced BRCA1 mRNA (P=0.0004), and to increased DNA methyltransferase DNMT3A (P=0.003) expression. Our data show that reduced BRCA1 expression owing to promoter hypermethylation is frequent in t-AML and that this could contribute to secondary leukaemogenesis.

Decreased hepatic expression of PPAR-gamma coactivator-1 in cholesterol cholelithiasis.

BACKGROUND: Cholesterol cholelithiasis (gallstone disease) is a common disease in the Western world. The aim of the present study was to analyze the hepatic expression of a number of nuclear receptors involved in bile acid metabolism in human cholesterol gallstone disease. MATERIALS AND METHODS: Surgical liver biopsies were obtained from 11 patients with untreated cholesterol cholelithiasis and nine gallstone-free subjects; mRNA levels of cholesterol 7alpha-hydroxylase (CYP7A1) and related nuclear receptors and coactivators were assayed by quantitative real-time RT-PCR. RESULTS: No differences between the two groups were detected in mRNA levels of CYP7A1 and related nuclear receptors, with the exception of peroxysome proliferator-activated receptor-gamma coactivator 1 (PGC-1), which was significantly (P < 0.01) less expressed in gallstone subjects. Expression of PGC-1 was linearly correlated with farnesoid X receptor (FXR) in gallstone patients (r = 0.87 on a log scale, P < 0.01), but not in control subjects; in gallstone patients PGC-1 expression was also correlated with hepatocyte nuclear factor 4 (HNF-4) (r = 0.78, P < 0.01). CONCLUSION: These findings suggest that PGC-1 can play a role in the prevention of cholesterol gallstone disease in humans; this might take place via interaction with the bile acid receptor FXR, whose protective role in cholelithiasis has been suggested by recent evidence in animal models and other coactivators. The present data might help to understand the pathophysiology and possibly focus on new therapeutical targets in cholesterol gallstone disease.