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Background T cell activation and programming from their naïve/resting state, characterized by widespread modifications in chromatin accessibility triggering extensive changes in transcriptional programs, is orchestrated by several cytokines and transcription regulators. PRDM1 and PRDM2 encode for proteins with PR/SET and zinc finger domains that control several biological processes, including cell differentiation, through epigenetic regulation of gene expression. Different transcripts leading to main protein isoforms with (PR +) or without (PR-) the PR/SET domain have been described. Although many studies have established the critical PRDM1 role in hematopoietic cell differentiation, maintenance and/or function, the single transcript contribution has not been investigated before. Otherwise, very few evidence is currently available on PRDM2. Here, we aimed to analyze the role of PRDM1 and PRDM2 different transcripts as mediators of T lymphocyte activation. Methods We analyzed the transcription signature of the main variants from PRDM1 (BLIMP1a and BLIMP1b) and PRDM2 (RIZ1 and RIZ2) genes, in human T lymphocytes and Jurkat cells overexpressing PRDM2 cDNAs following activation through different signals. Results T lymphocyte activation induced an early increase of RIZ2 and RIZ1 followed by BLIMP1b increase and finally by BLIMP1a increase. The “first” and the “second” signals shifted the balance towards the PR- forms for both genes. Interestingly, the PI3K signaling pathway modulated the RIZ1/RIZ2 ratio in favor of RIZ1 while the balance versus RIZ2 was promoted by MAPK pathway. Cytokines mediating different Jak/Stat signaling pathways (third signal) early modulated the expression of PRDM1 and PRDM2 and the relationship of their different transcripts confirming the early increase of the PR- transcripts. Different responses of T cell subpopulations were also observed. Jurkat cells showed that the acute transient RIZ2 increase promoted the balancing of PRDM1 forms towards BLIMP1b. The stable forced expression of RIZ1 or RIZ2 induced a significant variation in the expression of key transcription factors involved in T lymphocyte differentiation. The BLIMP1a/b balance shifted in favor of BLIMP1a in RIZ1-overexpressing cells and of BLIMP1b in RIZ2-overexpressing cells. Conclusions This study provides the first characterization of PRDM2 in T-lymphocyte activation/differentiation and novel insights on PRDM1 and PRDM2 transcription regulation during initial activation phases.

Abstract: Breast cancer, even today, can cause death. Therefore, prevention and early detection are fundamental factors. The mechanisms that favour it are genetic and epigenetic, and seem to play a significant role; also, the microbiota can change estrogen levels and can induce chronic inflammation in the neoplastic site, alternating the balance between proliferation and cell death. Activated steroid hormone receptors induce transcription of genes that encode for proteins involved in cell proliferation and activate another transduction pathway, inducing cell cycle progression and cell migration. These important studies have allowed to develop therapies with selective modulators of estrogen receptors (SERMs), able to block their proliferative and pro-tumorigenic action. Of fundamental importance is also the role played by the microbiota in regulating the metabolism of estrogens and their levels in the blood. There are microbial populations that are able to promote the development of breast cancer, through the production of enzymes responsible for the deconjugation of estrogens, the increase of these in the intestine, subsequent circulation and migration to other locations, such as the udder. Other microbial populations are, instead, able to synthesize estrogen compounds or mimic estrogenic action, and interfere with the metabolism of drugs, affecting the outcome of therapies. The microbial composition of the intestine and hormonal metabolism depend largely on eating habits; the consumption of fats and proteins favours the increase of estrogen in the blood, unlike a diet rich in fiber. Therefore, in-depth knowledge of the microbiota present in the intestine-breast axis could, in the future, encourage the development of new diagnostic and therapeutic approaches to breast cancers.

Histone deacetylase inhibitors (HDACi) are promising anticancer drugs. Although some HDACi have entered the clinic, the mechanism(s) underlying their tumor selectivity are poorly understood. Experimental Design/Results: Using gene expression analysis, we define a core set of 6 genes commonly regulated in acute myeloid leukemia (AML) blasts and cell lines. c-Myc, the most prominently modulated, is preferentially altered in leukemia. Upon HDACi treatment, c-Myc is acetylated at lysine 323 and its expression decreases, leading to TRAIL activation and apoptosis. c-Myc binds to the TRAIL promoter on the proximal GC box through Sp1 or Miz1, impairing TRAIL activation. HDACi exposure triggers TRAIL expression, altering c-Myc-TRAIL binding. These events do not occur in normal cells. Excitingly, this inverse correlation between TRAIL and c-Myc is supported by HDACi treatment ex vivo of AML blasts and primary human breast cancer cells. The predictive value of c-Myc to HDACi responsiveness is confirmed in vivo in AML patients undergoing HDACi-based clinical trials. Purpose: Histone deacetylase inhibitors (HDACi) are promising anticancer drugs. Although some HDACi have entered the clinic, the mechanism(s) underlying their tumor selectivity are poorly understood. Experimental Design and Results: Using gene expression analysis, we define a core set of six genes commonly regulated in acute myeloid leukemia (AML) blasts and cell lines. MYC, the most prominently modulated, is preferentially altered in leukemia. Upon HDACi treatment, c-Myc is acetylated at lysine 323 and its expression decreases, leading to TRAIL activation and apoptosis. c-Myc binds to the TRAIL promoter on the proximal GC box through SP1 or MIZ1, impairing TRAIL activation. HDACi exposure triggers TRAIL expression, altering c-Myc-TRAIL binding. These events do not occur in normal cells. Excitingly, this inverse correlation between TRAIL and c-Myc is supported by HDACi treatment ex vivo of AML blasts and primary human breast cancer cells. The predictive value of c-Myc to HDACi responsiveness is confirmed in vivo in AML patients undergoing HDACi-based clinical trials. Conclusions: Collectively, our findings identify a key role for c-Myc in TRAIL deregulation and as a biomarker of the anticancer action of HDACi in AML. The potential improved patient stratification could pave the way toward personalized therapies.

Prostate cancer (PC) is one of the most frequently diagnosed cancers and a leading cause of cancer-related deaths in Western society. Current PC therapies prevalently target the functions of androgen receptor (AR) and may only be effective within short time periods, beyond which the majority of PC patients progress to castration-resistant PC (CRPC) and metastatic disease. The role of estradiol/estradiol receptor (ER) axis in prostate transformation and PC progression is well established. Further, considerable efforts have been made to investigate the mechanism by which somatostatin (SST) and somatostatin receptors (SSTRs) influence PC growth and progression. A number of therapeutic strategies, such as the combination of SST analogues with other drugs, show, indeed, strong promise. However, the effect of the combined treatment of SST analogues and estradiol on proliferation, epithelial mesenchyme transition (EMT) and migration of normal- and cancer-derived prostate cells has not been investigated so far. We now report that estradiol plays anti-proliferative and pro-apoptotic effect in non-transformed EPN prostate cells, which express both ERα and ERβ. A weak apoptotic effect is observed in transformed CPEC cells that only express low levels of ERβ. Estradiol increases, mainly through ERα activation, the expression of SSTRs in EPN, but not CPEC cells. As such, the hormone enhances the anti-proliferative effect of the SST analogue, pasireotide in EPN, but not CPEC cells. Estradiol does not induce EMT and the motility of EPN cells, while it promotes EMT and migration of CPEC cells. Addition of pasireotide does not significantly modify these responses. Altogether, our results suggest that pasireotide may be used, alone or in combination with other drugs, to limit the growth of prostate proliferative diseases, provided that both ER isoforms (α and β) are present. Further investigations are needed to better define the cross talk between estrogens and SSTRs as well as its role in PC.

Il testo Immunobiologia di Janeway è stato pensato per gli studenti dei corsi universitari, ma è così completo da essere adeguato anche come testo di riferimento per specializzandi e per gli stessi medici che praticano l’immunologia. Pur addentrandosi nel mondo della microbiologia, è chiaramente focalizzato sullo studio dell’immunologia e dei suoi principali eventi immunopatologici, quali le reazioni autoimmunitarie, le immunodeficienze, i trapianti e l’immunologia dei tumori. Questa nona edizione è stata completamente riorganizzata ed aggiornata e contiene più di cento immagini nuove. Nell’Appendice I, il Toolbox degli immunologi ha subito una totale rivisitazione, con l’aggiunta di nuove tecniche, tra cui il sistema CRISPR/Cas9 e tecniche di spettrometria di massa e di proteomica. Inoltre è stato creato un elenco di domande che serviranno agli studenti per riflettere attentamente e sintetizzare le conoscenze apprese in ogni capitolo e per preparare al meglio gli esami.

Prostate cancer is one of the most commonly diagnosed cancers in men, and androgen deprivation therapy still represents the primary treatment for prostate cancer patients. This approach, however, frequently fails and patients develop castration-resistant prostate cancer, which is almost untreatable. Cancer cells are characterized by a hierarchical organization, and stem/progenitor cells are endowed with tumor-initiating activity. Accumulating evidence indicates that prostate cancer stem cells lack the androgen receptor and are, indeed, resistant to androgen deprivation therapy. In contrast, these cells express classical (α and/or ß) and novel (GPR30) estrogen receptors, which may represent new putative targets in prostate cancer treatment. In the present review, we discuss the still-debated mechanisms, both genomic and non-genomic, by which androgen and estradiol receptors (classical and novel) mediate the hormonal control of prostate cell stemness, transformation, and the continued growth of prostate cancer. Recent preclinical and clinical findings obtained using new androgen receptor antagonists, anti-estrogens, or compounds such as enhancers of androgen receptor degradation and peptides inhibiting non-genomic androgen functions are also presented. These new drugs will likely lead to significant advances in prostate cancer therapy.

The PR/SET domain gene family (PRDM) encodes 19 different transcription factors that share a subtype of the SET domain [Su(var)3-9, enhancer-of-zeste and trithorax] known as the PRDF1-RIZ (PR) homology domain. This domain, with its potential methyltransferase activity, is followed by a variable number of zinc-finger motifs, which likely mediate protein&ndash, protein, protein&ndash, RNA, or protein&ndash, DNA interactions. Intriguingly, almost all PRDM family members express different isoforms, which likely play opposite roles in oncogenesis. Remarkably, several studies have described alterations in most of the family members in malignancies. Here, to obtain a pan-cancer overview of the genomic and transcriptomic alterations of PRDM genes, we reanalyzed the Exome- and RNA-Seq public datasets available at The Cancer Genome Atlas portal. Overall, PRDM2, PRDM3/MECOM, PRDM9, PRDM16 and ZFPM2/FOG2 were the most mutated genes with pan-cancer frequencies of protein-affecting mutations higher than 1%. Moreover, we observed heterogeneity in the mutation frequencies of these genes across tumors, with cancer types also reaching a value of about 20% of mutated samples for a specific PRDM gene. Of note, ZFPM1/FOG1 mutations occurred in 50% of adrenocortical carcinoma patients and were localized in a hotspot region. These findings, together with OncodriveCLUST results, suggest it could be putatively considered a cancer driver gene in this malignancy. Finally, transcriptome analysis from RNA-Seq data of paired samples revealed that transcription of PRDMs was significantly altered in several tumors. Specifically, PRDM12 and PRDM13 were largely overexpressed in many cancers whereas PRDM16 and ZFPM2/FOG2 were often downregulated. Some of these findings were also confirmed by real-time-PCR on primary tumors.

Histone deacetylase 2 (HDAC2) is overexpressed or mutated in several disorders such as hematological cancers, and plays a critical role in transcriptional regulation, cell cycle progression and developmental processes. Here, we performed comparative transcriptome analyses in acute myeloid leukemia to investigate the biological implications of HDAC2 silencing versus its enzymatic inhibition using epigenetic-based drug(s). By gene expression analysis of HDAC2-silenced vs wild-type cells, we found that HDAC2 has a specific role in leukemogenesis. Gene expression profiling of U937 cell line with or without treatment of the well-known HDAC inhibitor vorinostat (SAHA) identifies and characterizes several gene clusters where inhibition of HDAC2 ‘mimics’ its silencing, as well as those where HDAC2 is selectively and exclusively regulated by HDAC2 protein expression levels. These findings may represent an important tool for better understanding the mechanisms underpinning immune regulation, particularly in the study of major histocompatibility complex class II genes.

The Mr 110,000 lung resistance-related protein (LRP), also termed the major vault protein (MVP), constitutes >70% of subcellular ribonucleoprotein particles called vaults. Overexpression of LRP/MVP and vaults has been linked directly to MDR in cancer cells. Clinically, LRP/MVP expression can be of value to predict response to chemotherapy and prognosis. Monoclonal antibodies (MAbs) against LRP/MVP have played a critical role in determining the relevance of this protein in clinical drug resistance. We compared the applicability of the previously described MAbs LRP-56, LMR-5, LRP, 1027, 1032, and newly isolated MAbs MVP-9, MVP-16, MVP-18, and MVP-37 for the immunodetection of LRP/MVP by immunoblotting analysis and by immunocyto- and histochemistry. The availability of a broader panel of reagents for the specific and sensitive immunodetection of LRP/MVP should greatly facilitate biological and clinical studies of vault-related MDR.

Co-immunoprecipitation experiments in cell extract from cultured cells or target tissues indicated that estrogen receptor was complexed with the retinoblastoma binding protein RIZ in a ligand-dependent manner. Mapping of interaction sites indicated that in both proteins the same regions and motifs responsible for the interaction of transcriptional co-activator and nuclear receptors were involved. In cultured cells, estradiol induced a redistribution of RIZ protein within the nucleus and in the cytoplasm. A similar effect was produced in vivo , in prepuberal rat endometrium, by administration of a physiological dose of estradiol. Therefore, RIZ protein could be a specific effector of estrogen action downstream of the hormone-receptor interaction, presumably involved in proliferation control.

The production of monoclonal antibodies, by cloning hybridoma derived from the fusion of myeloma cells and spleen lymphocytes, has allowed to obtain great advances in many fields of biological knowledge. The use of specific antibodies to the estrogen receptor, in fact, has been an invaluable method to bring out its mechanisms of action and its effects, both genomic and extra-genomic. Here we describe, step by step, the production of monoclonal antibodies, starting from protocol for antigen preparation to the selection of antibody-secreting hybridoma.

PRDM (PRDI-BF1 and RIZ homology domain containing) protein family members are characterized by the presence of a PR domain and a variable number of Zn-finger repeats. Experimental evidence has shown that the PRDM proteins play an important role in gene expression regulation, modifying the chromatin structure either directly, through the intrinsic methyltransferase activity, or indirectly through the recruitment of chromatin remodeling complexes. PRDM proteins have a dual action: they mediate the effect induced by different cell signals like steroid hormones and control the expression of growth factors. PRDM proteins therefore have a pivotal role in the transduction of signals that control cell proliferation and differentiation and consequently neoplastic transformation. In this review, we describe pathways in which PRDM proteins are involved and the molecular mechanism of their transcriptional regulation.

""We report that in breast cancer cells, tyrosine phosphorylation of the estradiol receptor alpha (ERalpha) by Src regulates cytoplasmic localization of the receptor and DNA synthesis. Inhibition of Src or use of a peptide mimicking the ERalpha p-Tyr537 sequence abolishes ERalpha tyrosine phosphorylation and traps the receptor in nuclei of estradiol-treated MCF-7 cells. An ERalpha mutant carrying a mutation of Tyr537 to phenylalanine (ER537F) persistently localizes in nuclei of various cell types. In contrast with ERalpha wt, ER537F does not associate with Ran and its interaction with Crm1 is insensitive to estradiol. Thus, independently of estradiol, ER537F is retained in nuclei, where it entangles FKHR-driving cell cycle arrest. Chromatin immunoprecipitation analysis reveals that overexpression of ER537F in breast cancer cells enhances FKHR interaction with cyclin D1 promoter. This mutant also counteracts cell transformation by the activated forms of Src or PI3-K. In conclusion, in addition to regulating receptor localization, ERalpha phosphorylation by Src is required for hormone responsiveness of DNA synthesis in breast cancer cells.Oncogene advance online publication, 23 January 2012; doi:10.1038\\\/onc.2011.642.""

""The retinoblastoma protein-interacting zinc-finger (RIZ) gene, also known as PRDM2, encodes two protein products, RIZ1 and RIZ2, differing for the presence of a 202 aa domain, called PR domain, at the N-terminus of the RIZ1 molecule. While the histone H3 K9 methyltransferase activity of RIZ1 is associated with the negative control of cell proliferation, no information is currently available on either expression regulation of the RIZ2 form or on its biological activity. RIZ proteins act as ER co-activators and promote optimal estrogen response in female reproductive tissues. In estrogen-responsive cells, 17-beta estradiol modulates RIZ gene expression producing a shift in the balanced expression of the two forms. Here, we demonstrate that an estrogen-responsive element (ERE) within the RIZ promoter 2 is regulated in a ligand-specific manner by ERa, through both the AF1 and AF2 domains. The pattern of ERa binding, histone H4 acetylation, and histone H3 cyclical methylation of lysine 9 was comparable to other estrogen-regulated promoters. Association of topoisomerase II beta with the RIZ promoter 2 confirmed the transcriptional activation induced by estrogen. We hypothesize that RIZ2, acting as a negative regulator of RIZ1 function, mediates the proliferative effect of estrogen through regulation of survival and differentiation gene expression. J. Cell. Physiol. 227: 964975, 2012. (C) 2011 Wiley Periodicals, Inc.""

The heart and kidney are physiologically interconnected. Cardiorenal syndrome (CRS) is a pathological disorder where acute or chronic dysfunction in one organ may induce dysfunction in the other one. Although classical studies have proposed a role for hypertension, dyslipidemia and endothelial dysfunction, CRS should be considered as a complex molecular interplay of neurohumoral pathway activation including the sympathetic nervous system, the renin angiotensin aldosterone axis, the endothelin system and the arginine vasopressin system. This activation may induce vascular inflammation, oxidative stress, accelerated atherosclerosis, cardiac hypertrophy and both myocardial and intrarenal fibrosis with progression of CRS treatment. More recently, epigenetics has opened new pathogenic molecular routes for CRS. This will lead to a more rapid development of novel, safe and effective clinical therapies.

"Growing evidence supports the concept that dynamic intra-and inter-chromosomal links between specific loci contribute to the creation of cell type-specific gene expression profiles. Therefore, analysis of the establishment of peculiar functional correlations between sites, also distant on linear DNA, that govern the transcriptional process appears to be of fundamental relevance. We propose here an experimental approach showing that 17 beta-estradiol-induced transcription associates to formation of loops between the promoter and termination regions of hormone-responsive genes. This strategy reveals as a tool to be also suitably used, in conjunction with automated techniques, for an extensive analysis of sites shared by multiple genes for induced expression."

Raloxifene (RAL), a selective estrogen receptor (ER) modulator (SERM) seems to induce apoptosis in both androgen-dependent and -independent prostate cell (PC) lines via activation of ERβ and an antagonistic effect on ERα. In this study, we evaluated the effects of RAL on epithelial PC growth using the two following in vitro models: the androgen-dependent cell line EPN which expressed both ERs; and a stabilized epithelial cell line derived from a prostate cancer specimen (CPEC), which expressed low levels of ERβ and lacked ERα. In EPN cells, there was an increase in the pre-G1 apoptotic peak and a reduction in the S phase of the cell cycle with G0/G1 arrest after E2 or RAL treatment; bcl-2 mRNA and Bcl-2 protein levels were significantly reduced, while activated caspase-3 and Par-4 levels increased significantly after either E2 or RAL treatment; in addition, c-myc transcript was inhibited after 10−6 M RAL treatment. A dose-dependent increase of metallothionein II gene RNA level was also induced by RAL in EPN. In CPEC, there was only a weak apoptotic peak associated with caspase-3 activation and Par-4 increase after either E2 or RAL treatment; while c-myc transcript level increased. RAL induced a rapid but transient phosphorylation of ERK 1/2 in EPN cells but generated a sustained effect in CPEC. These findings suggest that RAL effects on PC growth control in vitro are cell-specific, depending on ERβ or ERβ/ERα relative expression levels. Moreover, this study demonstrated that RAL affected both transcriptional regulation and non-genomic signals, which resulted in the modulation of multiple signaling pathways of apoptosis and of cell cycle progression. J. Cell. Physiol. 226: 1334–1339, 2011. © 2010 Wiley-Liss, Inc.

The nuclear protein methyl-transferase Retinoblastoma-interacting zinc-finger protein 1 (RIZ1) is considered to be a downstream effector of estrogen action in target tissues. Silencing of RIZ1 expression is common in many tumors. We analyzed RIZ1 expression in normal and malignant prostate tissue and evaluated whether estradiol (E2) or dihydrotestosterone (DHT) treatment modulated RIZ1 in cultured prostate epithelial cells (PEC). Moreover, we studied the possible involvement of RIZ1 in estrogen action on the EPN prostate cell line, constitutively expressing both estrogen receptor (ER)-alpha and beta. RIZ1 protein, found in the nucleus of normal PECs by immunohistochemistry, was progressively lost in cancer tissues as the Gleason score increased and was only detected in the cytoplasmic compartment. RIZ1 transcript levels, as assayed by semi-quantitative RT-PCR in primary PEC cultures, were significantly reduced in cancer cells (P < 0.05). In EPN DHT treatment significantly increased RIZ1 transcript and protein levels (P < 0.05); E2 induced a reduction of S phase without significant changes of RIZ1 expression. In E2-treated EPN cell extracts RIZ co-immunoprecipitated with ERbeta and ERalpha. Our data demonstrate that RIZ1 is expressed in normal PECs and down-regulated in cancer cells, with a switch of its sub-cellular localization from the nucleus to the cytoplasm upon cancer grade progression. RIZ1 expression levels in the PECs were modulated by DHT or E2 treatment in vitro. Furthermore, the E2 effects on ER-expressing prostate cells involve RIZ1, which confirms a possible role for ER-mediated pathways in a non-classic E(2)-target tissue.

Hypertrophic scar (HS) and keloid (KL) are two forms of an abnormal cutaneous scarring process, mainly characterized by excessive extracellular matrix deposition and fibroblast proliferation. Despite the increased understanding of the molecular and cellular events leading to HS and KL, the pathogenesis of these lesions remains poorly understood. A pivotal role in the formation of abnormal scars has been ascribed to transforming growth factor-beta, whose activity appears to be mediated through a link with pathways acting via cyclooxygenases (COX-1 and COX-2). To date, there is no report on the in vivo expression of COX-1 and COX-2 in human HS and KL tissues. Therefore, using immunohistochemistry and Western blot analysis, we investigated 36 cases of KL, 32 cases of HS, and 25 cases of normal skin in order to define the localization and distribution of COX-1 and COX-2 in the tissues of these scar lesions and the overlying epidermis. The results mainly show the following: (a) a significant overexpression of COX-1 in HS tissues and the overlying epidermis as compared with normal skin and KL tissues and (b) a significant overexpression of COX-2 in KL tissue and the overlying epidermis in contrast to normal skin and HS tissues. Our data support the hypothesis that both COXs are involved in the pathogenesis of scar lesions in different ways and, particularly, COX-1 in the formation of HS and COX-2 in the formation of KL. In addition, the overexpression of COX-1 and COX-2 in the epidermis overlying HS and KL tissues, respectively, underlines the importance of epithelial-mesenchymal interactions in the pathogenesis of scar lesions.

Estrogen receptor (ER) was purified from calf uterus by immunoaffinity chromatography in the absence of the ligand. The purified ER consists of a mixture of monomer and homodimer forms of 67-kDa hormone-binding subunit (no 90-kDa heat shock protein is present). The purified ER was incubated with a 32P-labeled 61-basepair oligonucleotide containing the sequence of the estrogen response element (ERE) of the Xenopus laevis A2 vitellogenin gene. DNA mobility shift assays showed formation of specific complexes of the ERE containing oligonucleotide with ER, formation which did not require and was not affected by estradiol or antiestrogenic molecules. Both the monomer and the dimer were equally able to interact with the ERE-containing oligonucleotide. Sucrose gradient experiments showed that only the ER monomer is able to interact with an oligonucleotide in which a single mutation destroyed the dyad symmetry of ERE. Multiple symmetric mutations which did not alter the dyad symmetry of ERE nevertheless totally destroyed the ability of the oligonucleotide to form complexes with either the monomeric or dimeric form of ER. These results suggest that ER is able to bind to ERE independently of the presence of estradiol or other proteins and, therefore, that estradiol does not act by modulating the ability of ER to bind to ERE on DNA.

The recruitment of circulating endothelial progenitor cells (EPCs) might have a beneficial effect on the clinical course of several diseases. Endothelial damage and detachment of endothelial cells are known to occur in infection, tissue ischemia, and sepsis. These detrimental effects in EPCs are unknown. Here we elucidated whether human EPCs internalize Bartonella henselae constituting a circulating niche of the pathogen. B. henselae invades EPCs as shown by gentamicin protection assays and transmission electron microscopy (TEM). Dil-Ac-LDL/lectin double immunostaining and fluorescence-activated cell sorting (FACS) analysis of EPCs revealed EPC bioactivity after infection with B. henselae . Nitric oxide (NO) and its precursor l -arginine ( l -arg) exert a plethora of beneficial effects on vascular function and modulation of immune response. Therefore, we tested also the hypothesis that l -arg (1–30 mM) would affect the infection of B. henselae or tumor necrosis factor (TNF) in EPCs. Our data provide evidence that l -arg counteracts detrimental effects induced by TNF or Bartonella infections via NO (confirmed by DETA-NO and L-NMMA experiments) and by modulation of p38 kinase phosphorylation. Microarray analysis indicated several genes involved in immune response were differentially expressed in Bartonella -infected EPCs, whereas these genes returned in steady state when cells were exposed to sustained doses of l -arg. This mechanism may have broad therapeutic applications in tissue ischemia, angiogenesis, immune response, and sepsis.

Modifications at the N-terminal tails of nucleosomal histones a re re quired for effici ent transcription in vivo. W e a nalyzed how H3 histone methylation and demethylation cont rol e xpression of estrog en-responsive g enes and s how t hat a DNA-bound e strog en r ecep tor directs transcription b y p articipa t ing i n be n ding chromati n t o contact the RNA polyme rase II re crui ted t o t he p r omote r. This process i s driven by r eceptor-targeted demethyl atio n o f H 3 l ysine 9 at both enhancer and p romoter sites and is achieved by activation of re sident LSD1 demethylase. Localized d emethylation produces hydrogen peroxide, which modifies the s urrounding DNA and recruits 8-oxog uanine–DNA glycosylase 1and topoisomeraseIIb, t riggering chromatin and DNA c onfo rmational c hanges that are e ssential for e st rogen-induced t ranscr iption. O ur data show a s trategy t hat uses c ontrolled D NA damage and repair to guide prod uctive tra n scription.

The retinoblastoma protein-interacting zinc-finger (RIZ) gene, a member of the nuclear protein methyltransferase superfamily, is characterized by the presence of the N-terminal PR domain. The RIZ gene encodes for two proteins, RIZ1 and RIZ2. While RIZ1 contains the PR (PRDI-BF1 and RIZ homologous) domain, RIZ2 lacks it. RIZ gene expression is altered in a variety of human cancers and RIZ1 is now considered to be a candidate tumor suppressor. Estradiol treatment of MCF-7 cells produced a selective decrease of RIZ1 transcript and an increase of total RIZ mRNA. Experiments of chromatin immunoprecipitation indicated that RIZ2 protein expression was controlled by estrogen receptor and RIZ1 had a direct repressor function on c-myc gene expression. To investigate the role of RIZ gene products as regulators of the proliferation/differentiation transition, we analyzed the effects of forced suppression of RIZ1 induced in MCF-7 cells by siRNA of the PR domain-containing form. Silencing of RIZ1 expression stimulated cell proliferation, similar to the effect of estradiol on these cells, associated with a transient increase of c-myc expression.

BACKGROUND: The retinoblastoma-interacting zinc-finger gene RIZ is expressed in two forms (RIZ1 and RIZ2) that differ for the presence near the N-terminus of RIZ1 of a conserved domain, defined PR (PRDI-BF1-RIZ homology), homologous to a similar domain present in other proteins recognized as tumor suppressor gene products. The RIZ1 form is usually absent or expressed at low levels in tumor cells, whereas RIZ2 is frequently expressed. We investigated a possible involvement of RIZ1 in differentiation control using a myeloid cell maturation model that is easily modulated by retinoids and other agents. MATERIALS AND METHODS: HL60 or NB4 cell lines or patients' leukemic promyelocytes were treated with all- trans -retinoic acid or other agents to induce differentiation. RIZ gene expression was determined with reverse transcriptase polymerase chain reaction (RT-PCR) and RNase protection assay. Immunocytochemistry was performed to assess variation of the intracellular distribution of RIZ protein on all- trans-retinoic acid treatment. Forced expression of RIZ1 protein was obtained with a recombinant adenovirus containing RIZ1 cDNA. RESULTS: Treatment with retinoic acid induced a selective expression of RIZ1 in HL60 cell line. Retinoic acid effect was maximal at 7 days and correlated to the granulocytic differentiation of cells. A similar effect was obtained in retinoic acid-sensitive NB4 cell line or in patients' leukemic promyelocytes, but not in the retinoic acid-resistant cell line NB4.007/6 or in the U937 cell line. Selective expression of RIZ1 was also induced by 12-O-tetradecanoyl-phorbol-13-acetate in the U937 and HL60 cell lines and by 1,25-dihydroxyvitamin D(3) only in HL60 cells. In HL60 cells, RIZ1 was also induced by activation of a retinoid alpha receptor-independent maturation pathway based on retinoid X receptor agonist and protein kinase A synergism. In addition, retinoic acid produced a redistribution of the antigen within the nucleus in these cells. Forced expression of RIZ1 protein induced growth arrest and death of HL60 cells. CONCLUSIONS: The correlation between the selective expression of RIZ1 induced by retinoic acid, 12-O-tetradecanoyl-phorbol-13-acetate, or 1,25-dihydroxyvitamin D(3) and differentiation suggested that RIZ protein was involved in myeloid cell differentiation induced by these agents.

The aim of this study was to investigate the expression of estrogen receptor (ER) beta and alpha genes in normal (N) and malignant (C) primary cultures of human prostate epithelial cells (PEC) and fibroblasts (PFC) and in the prostate tissue donors. Both ERbeta and ERalpha messenger ribonucleic acids were found by RT-PCR analysis in six NPECs and normal prostate tissues and in only one of six CPECs and in the respective cancer tissue donor. The other five CPECs and related cancer tissue donors and all normal and cancer PFCs expressed ERalpha messenger ribonucleic acid alone. Immunoblot analysis, using a polyclonal anti-ERbeta (C-terminal) antibody, demonstrated ERbeta protein in all NPEC lysates and in one of the six CPECS: ERalpha protein was expressed in both NPECs and CPECs when a polyclonal antibody directed against the ERalpha N-terminal domain was used. In contrast, ERalpha protein was not detected in two of the six CPEC lysates when ERalpha C-terminal monoclonal antibodies were used. Using a set of primers designed to amplify the region from exons 6-8, RT-PCR analysis demonstrated the absence of the expected transcript in these cells. The present study shows that the ERbeta gene is expressed together with ERalpha in normal prostates and NPECs, whereas it is barely detectable in prostate cancer and CPECS: Moreover, in some CPECs, the ERalpha gene may be transcribed in a changed protein, resulting from the expression of a deletion variant. Together, these data suggest that prostate malignancy is associated with a potential disorder of ER-mediated pathways.