Tumor Burden Dictates the Neoantigen Features Required to Generate an Effective Cancer Vaccine

Tumor neoantigens (nAg) represent a promising target for cancer immunotherapy. The identification of nAgs that can generate T-cell responses and have therapeutic activity has been challenging. Here, we sought to unravel the features of nAgs required to induce tumor rejection. We selected clinically validated Great Ape-derived adenoviral vectors (GAd) as a nAg delivery system for differing numbers and combinations of nAgs. We assessed their immunogenicity and efficacy in murine models of low to high disease burden, comparing multi-epitope versus mono-epitope vaccines. We demonstrated that the breadth of immune response is critical for vaccine efficacy and having multiple immunogenic nAgs encoded in a single vaccine improves efficacy. The contribution of each single neoantigen was examined, leading to the identification of 2 nAgs able to induce CD8+ T cell-mediated tumor rejection. They were both active as individual nAgs in a setting of prophylactic vaccination, although to different extents. However, the efficacy of these single nAgs was lost in a setting of therapeutic vaccination in tumor-bearing mice. The presence of CD4+ T-cell help restored the efficacy for only the most expressed of the two nAgs, demonstrating a key role for CD4+ T cells in sustaining CD8+ T-cell responses and the necessity of an efficient recognition of the targeted epitopes on cancer cells by CD8+ T cells for an effective antitumor response. This study provides insight into understanding the determinants of nAgs relevant for effective treatment and highlights features that could contribute to more effective antitumor vaccines. See related Spotlight by Slingluff Jr, p. 382.

Enhanced pro-apoptotic activity of rituximab through IBTK silencing in non-Hodgkin lymphoma B-cells

Rituximab is a commonly used chemotherapeutic drug for patients with aggressive lymphomas, such as non-Hodgkin's lymphoma (NHL). Currently, the combination of Rituximab and chemotherapy (R-CHOP) stands as the most prevalent first-line therapy for NHL. Nevertheless, the development of new therapeutic approaches remains imperative. An increasing body of evidence highlights a novel role for IBTK in tumorigenesis and cancer growth. In this study, we aim to broaden our understanding of IBTK's function in B-lymphoma, with a particular focus on its impact on the expression of the oncogene MYC. Here, we assessed the effects of combining Rituximab with IBTK silencing on cell viability through cell cycle analysis and Annexin V assays in vitro. Furthermore, we leveraged the transplantability of Eμ-myc lymphomas to investigate whether the inhibition of IBTK could elicit anti-tumor effects in the treatment of lymphomas in vivo. Our data suggests that IBTK silencing may serve as an effective anti-tumor agent for aggressive B-Lymphomas, underscoring its role in promoting apoptosis when used in combination with Rituximab, both in in vitro and in vivo settings.

The common H232 STING allele shows impaired activities in DNA sensing, susceptibility to viral infection, and in monocyte cell function, while the HAQ variant possesses wild-type properties

Different innate immune pathways converge to Stimulator of interferon genes (STING) and trigger type I interferon responses after recognition of abnormal nucleic acids in the cells. This non-redundant function renders STING a major player in immunosurveillance, and an emerging target for cancer and infectious diseases therapeutics. Beyond somatic mutations that often occur in cancer, the human gene encoding STING protein, TMEM173 (STING1), holds great genetic heterogeneity; R232, HAQ (R71H-G230A-R293Q) and H232 are the most common alleles. Although some of these alleles are likely to be hypomorphic, their function is still debated, due to the available functional assessments, which have been performed in biased biological systems. Here, by using genetic background-matched models, we report on the functional evaluation of R232, HAQ and H232 variants on STING function, and on how these genotypes affect the susceptibility to clinically relevant viruses, thus supporting a potential contributing cause to differences in inter-individual responses to infections. Our findings also demonstrate a novel toll-like receptor-independent role of STING in modulating monocytic cell function and differentiation into macrophages. We further supported the interplay of STING1 variants and human biology by demonstrating how monocytes bearing the H232 allele were impaired in M1/M2 differentiation, interferon response and antigen presentation. Finally, we assessed the response to PD-1 inhibitor in a small cohort of melanoma patients stratified according to STING genotype. Given the contribution of the STING protein in sensing DNA viruses, bacterial pathogens and misplaced cancer DNA, these data may support the development of novel therapeutic options for infectious diseases and cancer.

Chronic Exposure to Chlorpyrifos Damages Thyroid Activity and Imbalances Hepatic Thyroid Hormones Signaling and Glucose Metabolism: Dependency of T3-FOXO1 Axis by Hyperglycemia

Early life exposure to Endocrine Disruptor Chemicals (EDCs), such as the organophosphate pesticide Chlorpyrifos (CPF), affects the thyroid activity and dependent process, including the glucose metabolism. The damage of thyroid hormones (THs) as a mechanism of action of CPF is underestimated because the studies rarely consider that TH levels and signaling are customized peripherally. Here, we investigated the impairment of metabolism/signaling of THs and lipid/glucose metabolism in the livers of 6-month-old mice, developmentally and lifelong exposed to 0.1, 1, and 10 mg/kg/die CPF (F1) and their offspring similarly exposed (F2), analyzing the levels of transcripts of the enzymes involved in the metabolism of T3 (Dio1), lipids (Fasn, Acc1), and glucose (G6pase, Pck1). Both processes were altered only in F2 males, affected by hypothyroidism and by a systemic hyperglycemia linked to the activation of gluconeogenesis in mice exposed to 1 and 10 mg/kg/die CPF. Interestingly, we observed an increase in active FOXO1 protein due to a decrease in AKT phosphorylation, despite insulin signaling activation. Experiments in vitro revealed that chronic exposure to CPF affected glucose metabolism via the direct modulation of FOXO1 activity and T3 levels in hepatic cells. In conclusion, we described different sex and intergenerational effects of CPF exposure on the hepatic homeostasis of THs, their signaling, and, finally, glucose metabolism. The data points to FOXO1-T3-glucose signaling as a target of CPF in liver.

miRNA-23a modulates sodium-hydrogen exchanger 1 expression: studies in medullary thick ascending limb of salt-induced hypertensive rats

BACKGROUND

The kidney is the main organ in the pathophysiology of essential hypertension. Although most bicarbonate reabsorption occurs in the proximal tubule, the medullary thick ascending limb (mTAL) of the nephron also maintains acid-base balance by contributing to 25% of bicarbonate reabsorption. A crucial element in this regulation is the sodium-hydrogen exchanger 1 (NHE1), a ubiquitous membrane protein controlling intracellular pH, where proton extrusion is driven by the inward sodium flux. MicroRNA (miRNA) expression of hypertensive patients significantly differs from that of normotensive subjects. The aim of this study was to determine the functional role of miRNA alterations at the mTAL level.

METHODS

By miRNA microarray analysis, we identified miRNA expression profiles in isolated mTALs from high sodium intake-induced hypertensive rats (HSD) versus their normotensive counterparts (NSD). In vitro validation was carried out in rat mTAL cells.

RESULTS

Five miRNAs involved in the onset of salt-sensitive hypertension were identified, including miR-23a, which was bioinformatically predicted to target NHE1 mRNA. Data demonstrated that miRNA-23a is downregulated in the mTAL of HSD rats while NHE1 is upregulated. Consistently, transfection of an miRNA-23a mimic in an mTAL cell line, using a viral vector, resulted in NHE1 downregulation.

CONCLUSION

NHE1, a protein involved in sodium reabsorption at the mTAL level and blood pressure regulation, is upregulated in our model. This was due to a downregulation of miRNA-23a. Expression levels of this miRNA are influenced by high sodium intake in the mTALs of rats. The downregulation of miRNA-23a in humans affected by essential hypertension corroborate our data and point to the potential role of miRNA-23a in the regulation of mTAL function following high salt intake.

The Lack of STING Impairs the MHC-I Dependent Antigen Presentation and JAK/STAT Signaling in Murine Macrophages

STING is a transmembrane ER resident protein that was initially described as a regulator of innate immune response triggered by viral DNA and later found to be involved in a broader range of immune processes. Here, we assessed its role in the antigen presentation by generating a STING KO macrophage cell line. In the absence of STING, we observed an impaired OVA-derived SIINFEKL peptide presentation together with a decreased level of MHC-I complex on the plasma membrane, likely due to a decreased mRNA expression of β2 m light chain as no relevant alterations of the peptide-loading complex (TAPs) were found. Moreover, JAK-STAT signaling resulted in impaired STING KO cells following OVA and LPS treatments, suggesting a dampened activation of immune response. Our data revealed a new molecular role of STING in immune mechanisms that could elucidate its role in the pathogenesis of autoimmune disorders and cancer.

Thyroid Cancer and Fibroblasts

Thyroid cancer is the most common type of endocrine cancer, and its prevalence continue to rise. Non-metastatic thyroid cancer patients are successfully treated. However, looking for new therapeutic strategies is of great importance for metastatic thyroid cancers that still lead to death. With respect to this, the tumor microenvironment (TME), which plays a key role in tumor progression, should be considered as a new promising therapeutic target to hamper thyroid cancer progression. Indeed, thyroid tumors consist of cancer cells and a heterogeneous and ever-changing niche, represented by the TME, which contributes to establishing most of the features of cancer cells. The TME consists of extracellular matrix (ECM) molecules, soluble factors, metabolites, blood and lymphatic tumor vessels and several stromal cell types that, by interacting with each other and with tumor cells, affect TME remodeling, cancer growth and progression. Among the thyroid TME components, cancer-associated fibroblasts (CAFs) have gained more attention in the last years. Indeed, recent important evidence showed that thyroid CAFs strongly sustain thyroid cancer growth and progression by producing soluble factors and ECM proteins, which, in turn, deeply affect thyroid cancer cell behavior and aggressiveness. Hence, in this article, we describe the thyroid TME, focusing on the desmoplastic stromal reaction, which is a powerful indicator of thyroid cancer progression and an invasive growth pattern. In addition, we discuss the origins and features of the thyroid CAFs, their influence on thyroid cancer growth and progression, their role in remodeling the ECM and their immune-modulating functions. We finally debate therapeutic perspectives targeting CAFs.

P367 EFFECTS OF BIOARGININA® C SUPPLEMENTATION IN SECONDARY PREVENTION OF POST–COVID 19 HIGH CARDIOVASCULAR RISK PATIENTS

Background

Post COVID–19 syndrome is characterized by chronic fatigue, shortness of breath, dry cough, headache, cognitive difficulties. The complexity of the clinical feature can be explained by a pre–existing endothelial dysfunction (particularly in the patient with high cardiovascular risk) exacerbated and/or linked to viral infection. In the cardiorespiratory rehabilitation program (RCR), the introduction of nutritional supports, vitamins and aminoacids, can be considered a useful approach to post–Covid syndrome. There are observations of positive results with the use of association of oral L–arginine + liposomal vitamin C (Bioarginina®C, 1.66g 2 bottles / day).

Aim of the Study

to evaluate the effects of the use of combination of oral L–arginine + liposomal vitamin C (Bioarginina®C, 1.66g 2 bottles/day) on the functional capacity measured with the six minute walking test (6MWT) of subjects during RCR post COVID 19.

Methods

50 patients with high cardiovascular risk (38 M and 12 F), with mean age 58 ± 7 years, (Group A) undergoing integration with two bottles of L arginine and liposomal vitamin C were examined above for 90 days during the RCR cycle. These had been positive to molecular COVID–19 nasopharyngeal swab test for a period ranging from 15 to 30 days. As a control population, the results obtained with standard treatment in 30 patients with high cardiovascular risk (17 M and 13 F) (mean age 61 ± 8 years) (Group B) after RCR post COVID 19 infection, were examined. The ability to perform normal daily activities was analyzed with the six minute walk test (6MWT) which measures the distance that a subject can run on a flat surface, walking as fast as possible in six minutes, including any interruptions that patient deems necessary. The statistical analysis was performed with the Student‘s T test for paired data. A value of p < 0.05 was considered statistical significant.

Results

At 3 months, improvement in 6MWT values was observed in both groups in Group A: 289 ± 96 m vs 419 ± 105 m (p < 0.0001) – Group B: 280 ± 88 m vs 332 ± 98 m (p < 0.021). However in Group A, these was more significant.

Conclusions

Our data confirm the improvement in the physical performance of post COVID 19 patients with introduction of nutritional supports with L–arginine and liposomal vitamin C.

P99 LONG TERM DUAL ANTIPLATELET THERAPY AFTER MYOCARDIAL INFARCTION IN CLINICAL PRACTICE: IMPACT OF NUISANCE BLEEDING ON MEDICATION ADHERENCE

Background

Long term dual antiplatelet therapy (LTDAPT) with ticagrelor 60 mg and low–dose aspirin are indicated after acute coronary syndrome (ACS) for the secondary prevention of atherothrombotic events in high–risk patients with a history of ACS of at least 1 year. LTDAPT had a well tolerability and safety profile, but the risk of TIMI major bleeding was increased. However even non significant bleeding may be important because have an effect on quality of life and therefore may lead to treatment discontinuation. Objective To understand the experiences of patients with LTDAPT and nuisance bleeding, and their impact on medication adherence.

Methods

We retrospectively reviewed 225 patients in follow up after ACS with at least one high risk condition (Fig. 1), treated with ticagrelor 60 mg twice daily (after 90 mg twice daily for 12 months). The outpatient follow–up program after hospitalization provides a visits at day 30 after discharge and subsequently after 3 months, then continuing with six–monthly checks. The intensity of bleeding was assessed according to the TIMI score. Any overt bleeding event that did not meet the criteria of major and minor was defined “minimal”.

Results

they are shown in Fig. 2. Minmal bleedings were present in 49 patients (21%), but were not a cause for discontinuation of therapy. However 39 (79%) subjects had asked opinion on stop the therapy at the telephone consultation. We found that: (1) participants adhered to treatment when they believed long term DAPT was important to health outcomes; (2) those who experienced nuisance bleeding reported symptoms to be mild and manageable; (3) participants’ and their family’s understanding of LTDAPT risks and benefits, and their ability to manage symptoms, influenced medication adherence. Factors influencing long term DAPT knowledge included access to medication counselling, engaging with information communicated during medication counselling, and access to timely, relevant and expert information and advice after discharge from hospital.

Conclusions

All adverse events judged to be “not serious” in trials may have an effect on quality of life and therefore may lead to treatment discontinuation. The need to educate the patient in order to improve adherence should therefore be emphasized. The authors underline the importance of careful outpatient follow–up and constant counselling in order to check out compliance and possible adverse effect of long term DAPT risks treatment.

Metabolites Profiling of Melanoma Interstitial Fluids Reveals Uridine Diphosphate as Potent Immune Modulator Capable of Limiting Tumor Growth

Tumor interstitial fluid (TIF) surrounds and perfuses tumors and collects ions, metabolites, proteins, and extracellular vesicles secreted by tumor and stromal cells. Specific metabolites, accumulated within the TIF, could induce metabolic alterations of immune cells and shape the tumor microenvironment. We deployed a metabolomic approach to analyze the composition of melanoma TIF and compared it to the plasma of C57BL6 mice, engrafted or not with B16-melanoma cells. Among the classes of metabolites analyzed, monophosphate and diphosphate nucleotides resulted enriched in TIF compared to plasma samples. The analysis of the effects exerted by guanosine diphosphate (GDP) and uridine diphosphate (UDP) on immune response revealed that GDP and UDP increased the percentage of CD4+CD25+FoxP3- and, on isolated CD4+ T-cells, induced the phosphorylation of ERK, STAT1, and STAT3; increased the activity of NF-κB subunits p65, p50, RelB, and p52; increased the expression of Th1/Th17 markers including IFNγ, IL17, T-bet, and RORγt; and reduced the expression of IL13, a Th2 marker. Finally, we observed that local administrations of UDP in B16-engrafted C57BL6 mice reduced tumor growth and necrotic areas. In addition, UDP-treated tumors showed a higher presence of MHCIIhi tumor-associated macrophage (TAM) and of CD3+CD8+ and CD3+CD4+ tumor-infiltrating T-lymphocytes (TILs), both markers of anti-tumor immune response. Consistent with this, intra-tumoral gene expression analysis revealed in UDP-treated tumors an increase in the expression of genes functionally linked to anti-tumor immune response. Our analysis revealed an important metabolite acting as mediator of immune response, which could potentially represent an additional tool to be used as an adjuvant in cancer immunotherapy.

ZFP36L2 Role in Thyroid Functionality

Thyroid hormone levels are usually genetically determined. Thyrocytes produce a unique set of enzymes that are dedicated to thyroid hormone synthesis. While thyroid transcriptional regulation is well-characterized, post-transcriptional mechanisms have been less investigated. Here, we describe the involvement of ZFP36L2, a protein that stimulates degradation of target mRNAs, in thyroid development and function, by in vivo and in vitro gene targeting in thyrocytes. Thyroid-specific Zfp36l2-/- females were hypothyroid, with reduced levels of circulating free Thyroxine (cfT4) and Triiodothyronine (cfT3). Their hypothyroidism was due to dyshormonogenesis, already evident one week after weaning, while thyroid development appeared normal. We observed decreases in several thyroid-specific transcripts and proteins, such as Nis and its transcriptional regulators (Pax8 and Nkx2.1), and increased apoptosis in Zfp36l2-/- thyroids. Nis, Pax8, and Nkx2.1 mRNAs were also reduced in Zfp36l2 knock-out thyrocytes in vitro (L2KO), in which we confirmed the increased apoptosis. Finally, in L2KO cells, we showed an altered response to TSH stimulation regarding both thyroid-specific gene expression and cell proliferation and survival. This result was supported by increases in P21/WAF1 and p-P38MAPK levels. Mechanistically, we confirmed Notch1 as a target of ZFP36L2 in the thyroid since its levels were increased in both in vitro and in vivo models. In both models, the levels of Id4 mRNA, a potential inhibitor of Pax8 activity, were increased. Overall, the data indicate that the regulation of mRNA stability by ZFP36L2 is a mechanism that controls the function and survival of thyrocytes.

Multi Species Analyses Reveal Testicular T3 Metabolism and Signalling as a Target of Environmental Pesticides

Thyroid hormones (THs) regulate many biological processes in vertebrates, including reproduction. Testicular somatic and germ cells are equipped with the arrays of enzymes (deiodinases), transporters, and receptors necessary to locally maintain the optimal level of THs and their signalling, needed for their functions and spermatogenesis. Pesticides, as chlorpyrifos (CPF) and ethylene thiourea (ETU), impair the function of thyroid and testis, affecting male fertility. However, their ability to disarrange testicular T3 (t-T3) metabolism and signalling is poorly considered. Here, a multi-species analysis involving zebrafish and mouse suggests the damage of t-T3 metabolism and signalling as a mechanism of gonadic toxicity of low-doses CPF and ETU. Indeed, the developmental exposure to both compounds reduces Dio2 transcript in both models, as well as in ex-vivo cultures of murine seminiferous tubules, and it is linked to alteration of steroidogenesis and germ cell differentiation. A major impact on spermatogonia was confirmed molecularly by the expression of their markers and morphologically evidenced in zebrafish. The results reveal that in the adopted models, exposure to both pesticides alters the t-T3 metabolism and signalling, affecting the reproductive capability. Our data, together with previous reports suggest zebrafish as an evaluable model in assessing the action of compounds impairing locally T3 signalling.

Ovarian Aging: Role of Pituitary-Ovarian Axis Hormones and ncRNAs in Regulating Ovarian Mitochondrial Activity

The number of mitochondria in the oocyte along with their functions (e.g., energy production, scavenger activity) decline with age progression. Such multifaceted functions support several processes during oocyte maturation, ranging from energy supply to synthesis of the steroid hormones. Hence, it is hardly surprising that their impairment has been reported in both physiological and premature ovarian aging, wherein they are crucial players in the apoptotic processes that arise in aged ovaries. In any form, ovarian aging implies the progressive damage of the mitochondrial structure and activities as regards to ovarian germ and somatic cells. The imbalance in the circulating hormones and peptides (e.g., gonadotropins, estrogens, AMH, activins, and inhibins), active along the pituitary-ovarian axis, represents the biochemical sign of ovarian aging. Despite the progress accomplished in determining the key role of the mitochondria in preserving ovarian follicular number and health, their modulation by the hormonal signalling pathways involved in ovarian aging has been poorly and randomly explored. Yet characterizing this mechanism is pivotal to molecularly define the implication of mitochondrial dysfunction in physiological and premature ovarian aging, respectively. However, it is fairly difficult considering that the pathways associated with ovarian aging might affect mitochondria directly or by altering the activity, stability and localization of proteins controlling mitochondrial dynamics and functions, either unbalancing other cellular mediators, released by the mitochondria, such as non-coding RNAs (ncRNAs). We will focus on the mitochondrial ncRNAs (i.e., mitomiRs and mtlncRNAs), that retranslocate from the mitochondria to the nucleus, as active players in aging and describe their role in the nuclear-mitochondrial crosstalk and its modulation by the pituitary-ovarian hormone dependent pathways. In this review, we will illustrate mitochondria as targets of the signaling pathways dependent on hormones and peptides active along the pituitary/ovarian axis and as transducers, with a particular focus on the molecules retrieved in the mitochondria, mainly ncRNAs. Given their regulatory function in cellular activities we propose them as potential diagnostic markers and/or therapeutic targets.

Integrity of the Antiviral STING-mediated DNA Sensing in Tumor Cells Is Required to Sustain the Immunotherapeutic Efficacy of Herpes Simplex Oncolytic Virus

Simple Summary

Oncolytic viruses are emerging immunotherapeutics in cancer treatments. The conflicting role of innate immunity in the antitumor activity of oncolytic viruses is still a matter of debate. The STING-dependent DNA sensing axis is considered detrimental for viral replication and cancer cell clearance. Accordingly, we observed that STING loss in tumor cells was associated with improved lytic potential by a herpes-based oncolytic virus. However, STING-knockout cancer cells infected with the oncolytic virus showed impaired immunogenicity, as immunogenic cell death was improperly triggered. In agreement with these observations, STING-knockout tumors raised in a murine syngeneic model were more resistant to a combined treatment of the oncolytic virus with PD-1 blockade. The present study demonstrates the antitumor benefit of antiviral immunity and sheds lights on the mechanisms of immune resistance to oncovirotherapy exerted by STING-loss in tumor cells.

Abstract

The dichotomic contribution of cancer cell lysis and tumor immunogenicity is considered essential for effective oncovirotherapy, suggesting that the innate antiviral immune response is a hurdle for efficacy of oncolytic viruses. However, emerging evidence is resizing this view. By sensing cytosolic DNA, the cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING) axis can both counteract viral spread and contribute to the elicitation of adaptive immunity via type I interferon responses. In this paper, we analyzed the tumor-resident function of Sting-mediated DNA sensing in a combined approach of oncovirotherapy and PD-1 immune checkpoint blockade, in an immunocompetent murine model. While supporting increased lytic potential by oncolytic HER2-retargeted HSV-1 in vitro and in vivo, Sting-knockout tumors showed molecular signatures of an immunosuppressive tumor microenvironment. These signatures were correspondingly associated with ineffectiveness of the combination therapy in a model of established tumors. Results suggest that the impairment in antiviral response of Sting-knockout tumors, while favoring viral replication, is not able to elicit an adequate immunotherapeutic effect, due to lack of immunogenic cell death and the inability of Sting-knockout cancer cells to promote anti-tumor adaptive immune responses. Accordingly, we propose that antiviral, tumor-resident Sting provides fundamental contributions to immunotherapeutic efficacy of oncolytic viruses.

Peripheral T3 signaling is the target of pesticides in zebrafish larvae and adult liver

The intra-tissue levels of thyroid hormones (THs) regulate organ functions. Environmental factors can impair these levels by damaging the thyroid gland and/or peripheral TH metabolism. We investigated the effects of embryonic and/or long-life exposure to low-dose pesticides, ethylene thiourea (ETU), chlorpyrifos (CPF) and both combined on intra-tissue T4/T3 metabolism/signaling in zebrafish at different life stages. Hypothyroidism was evident in exposed larvae that showed reduced number of follicles and induced tshb mRNAs. Despite that, we found an increase in free T4 (fT4) and free T3 (fT3) levels/signaling that was confirmed by transcriptional regulation of TH metabolic enzymes (deiodinases) and T3-regulated mRNAs (cpt1, igfbp1a). Second-generation larvae showed that thyroid and TH signaling was affected even when not directly exposed, suggesting the role of parental exposure. In adult zebrafish, we found that sex-dependent damage of hepatic T3 level/signaling was associated with liver steatosis, which was more pronounced in females, with sex-dependent alteration of transcripts codifying the key enzymes involved in 'de novo lipogenesis' and β-oxidation. We found impaired activation of liver T3 and PPARα/Foxo3a pathways whose deregulation was already involved in mammalian liver steatosis. The data emphasizes that the intra-tissue imbalance of the T3 level is due to thyroid endocrine disruptors (THDC) and suggests that the effect of a slight modification in T3 signaling might be amplified by its direct regulation or crosstalk with PPARα/Foxo3a pathways. Because T3 levels define the hypothyroid/hyperthyroid status of each organ, our findings might explain the pleiotropic and site-dependent effects of pesticides.

Epigenetic deregulation in cancer: Enzyme players and non-coding RNAs

Data obtained from cutting-edge research have shown that deregulated epigenetic marks are critical hallmarks of cancer. Rapidly emerging scientific evidence has helped in developing a proper understanding of the mechanisms leading to control of cellular functions, from changes in chromatin accessibility, transcription and translation, and in post-translational modifications. Firstly, mechanisms of DNA methylation and demethylation are introduced, as well as modifications of DNA and RNA, with particular focus on N6-methyladenosine (m6A), discussing the effects of these modifications in normal cells and in malignancies. Then, chromatin modifying proteins and remodelling complexes are discussed. Many enzymes and accessory proteins in these complexes have been found mutated or have undergone differential splicing, leading to defective protein complexes. Epigenetic mechanisms acting on nucleosomes by polycomb repressive complexes and on chromatin by SWI/SNF complexes on nucleosome assembly/disassembly, as well as main mutated genes linked to cancers, are reviewed. Among enzymes acting on histones and other proteins erasing the reversible modifications are histone deacetylases (HDACs). Sirtuins are of interest since most of these enzymes not only deacylate histones and other proteins, but also post-translationally modify proteins adding a Mono-ADP-ribose (MAR) moiety. MAR can be read by MACRO-domain containing proteins such as histone MacroH2A1, with specific function in chromatin assembly. Finally, recent advances are presented on non-coding RNAs with a scaffold function, prospecting their role in assembly of chromatin modifying complexes, recruiting enzyme players to chromatin regions. Lastly, the imbalance in metabolites production due to mitochondrial dysfunction is presented, with the potential of these metabolites to inhibit enzymes, either writers, readers or erasers of epitranscriptome marks. In the perspectives, studies are overwied on drugs under development aiming to limit excessive enzyme activities and to reactivate chromatin modifying complexes, for therapeutic application. This knowledge may lead to novel drugs and personalised medicine for cancer patients.

Thyroid Hormones and Functional Ovarian Reserve: Systemic vs. Peripheral Dysfunctions

Thyroid hormones (THs) exert pleiotropic effects in different mammalian organs, including gonads. Genetic and non-genetic factors, such as ageing and environmental stressors (e.g., low-iodine intake, exposure to endocrine disruptors, etc.), can alter T4/T3 synthesis by the thyroid. In any case, peripheral T3, controlled by tissue-specific enzymes (deiodinases), receptors and transporters, ensures organ homeostasis. Conflicting reports suggest that both hypothyroidism and hyperthyroidism, assessed by mean of circulating T4, T3 and Thyroid-Stimulating Hormone (TSH), could affect the functionality of the ovarian reserve determining infertility. The relationship between ovarian T3 level and functional ovarian reserve (FOR) is poorly understood despite that the modifications of local T3 metabolism and signalling have been associated with dysfunctions of several organs. Here, we will summarize the current knowledge on the role of TH signalling and its crosstalk with other pathways in controlling the physiological and premature ovarian ageing and, finally, in preserving FOR. We will consider separately the reports describing the effects of circulating and local THs on the ovarian health to elucidate their role in ovarian dysfunctions.

Effects of Long-Term Citrate Treatment in the PC3 Prostate Cancer Cell Line

Acute administration of a high level of extracellular citrate displays an anti-proliferative effect on both in vitro and in vivo models. However, the long-term effect of citrate treatment has not been investigated yet. Here, we address this question in PC3 cells, a prostate-cancer-derived cell line. Acute administration of high levels of extracellular citrate impaired cell adhesion and inhibited the proliferation of PC3 cells, but surviving cells adapted to grow in the chronic presence of 20 mM citrate. Citrate-resistant PC3 cells are significantly less glycolytic than control cells. Moreover, they overexpress short-form, citrate-insensitive phosphofructokinase 1 (PFK1) together with full-length PFK1. In addition, they show traits of mesenchymal-epithelial transition: an increase in E-cadherin and a decrease in vimentin. In comparison with PC3 cells, citrate-resistant cells display morphological changes that involve both microtubule and microfilament organization. This was accompanied by changes in homeostasis and the organization of intracellular organelles. Thus, the mitochondrial network appears fragmented, the Golgi complex is scattered, and the lysosomal compartment is enlarged. Interestingly, citrate-resistant cells produce less total ROS but accumulate more mitochondrial ROS than control cells. Consistently, in citrate-resistant cells, the autophagic pathway is upregulated, possibly sustaining their survival. In conclusion, chronic administration of citrate might select resistant cells, which could jeopardize the benefits of citrate anticancer treatment.

Transcriptional landscape of mouse-aged ovaries reveals a unique set of non-coding RNAs associated with physiological and environmental ovarian dysfunctions

The progressive and physiological decline in ovarian function depends on the rate of follicular loss by atresia, contributing to the reduction in ovarian reserve. Genetics and environmental factors play important roles in ovarian senescence and in the onset of ovarian dysfunctions such as diminished ovarian reserve. A better understanding of the mechanisms underlying ovarian aging and their regulation by genetic and environmental factors is needed to evaluate ovarian reserve and to predict fertility potential by identification of more accurate and less invasive markers. We report transcriptomic data (i) implicating novel (e.g. EIF2 signalling) and well-known pathways (e.g. TGFβ signalling), and (ii) defining a unique set of non-coding RNA (ncRNA), both associated with ovarian function. The latter includes miRNAs (e.g. Mir143 and Mir145), snoRNAs (e.g. Snord16a and Snora34), and one lncRNA (Gas5), which are differentially expressed in middle-aged ovaries (12 months) vs young-aged (3 months) from CD1 mice. Experimental analysis confirms that ovary lifespan varies across genetic backgrounds in mice and, genetics influences the response to environmental perturbations such as diet. Moreover, the identified ncRNAs were verified in a model of reproductive dysfunction promoted by the environmental toxicant ethylenthiourea. We also report the increase of miRNA143 and miRNA145 in follicular fluid of women with diminished ovarian reserve. Their levels inversely correlate with the hormonal profile and with the number of the oocytes recruited upon hormonal stimulation. Overall, we report a transcriptomic signature for ovarian dysfunction in vivo that provides a valuable resource for translational research in human reproductive aging.

The expression of inhibitor of bruton's tyrosine kinase gene is progressively up regulated in the clinical course of chronic lymphocytic leukaemia conferring resistance to apoptosis

Chronic lymphocytic leukaemia (CLL) is the most common B-cell malignancy with a variable clinical outcome. Biomarkers of CLL progression are required for optimising prognosis and therapy. The Inhibitor of Bruton’s tyrosine kinase—isoform α (IBTKα) gene encodes a substrate receptor of Cullin 3-dependent E3 ubiquitin ligase, and promotes cell survival in response to the reticulum stress. Searching for novel markers of CLL progression, we analysed the expression of IBTKα in the peripheral blood B-cells of CLL patients, before and after first line therapy causing remission. The expression of IBTKα was significantly increased in disease progression, and decreased in remission after chemotherapy. Consistently with a pro-survival action, RNA interference of IBTKα increased the spontaneous and Fludarabine-induced apoptosis of MEC-1 CLL cells, and impaired the cell cycle of DeFew B-lymphoma cells by promoting the arrest in G0/G1 phase and apoptosis. Consistently, RNA interference of IBTKα up regulated the expression of pro-apoptotic genes, including TNF, CRADD, CASP7, BNIP3 and BIRC3. Our results indicate that IBTKα is a novel marker of CLL progression promoting cell growth and resistance to apoptosis. In this view, IBTKα may represent an attractive cancer drug target for counteracting the therapy-resistance of tumour cells.

Carcinogenic risk and Bisphenol A exposure: A focus on molecular aspects in endoderm derived glands

Epidemiological and experimental evidence associates the exposure to Bisphenol A with the increase of cancer risk in several organs, including prostate. BPA targets different pathways involved in carcinogenicity including the Nuclear Receptors (i.e. estrogen and androgen receptors), stress regulated proteins and, finally, epigenetic changes. Here, we analyse BPA-dependent carcinogenesis in endoderm-derived glands, thyroid, liver, pancreas and prostate focusing on cell signalling, DNA damage repair pathways and epigenetic modifications. Mainly, we gather molecular data evidencing harmful effects at doses relevant for human risk (low-doses). Since few molecular data are available, above all for the pancreas, we analysed transcriptomic data generated in our laboratory to suggest possible mechanisms of BPA carcinogenicity in endoderm-derived glands, discussing the role of nuclear receptors and stress/NF-kB pathways. We evidence that an in vitro toxicogenomic approach might suggest mechanisms of toxicity applicable to cells having the same developmental origin. Although we cannot draw firm conclusions, published data summarized in this review suggest that exposure to BPA, primarily during the developmental stages, represents a risk for carcinogenesis of endoderm-derived glands.

The Roles of miR-25 and its Targeted Genes in Development of Human Cancer

microRNAs (miRNAs) are small noncoding RNAs able to suppress gene expression by targeting messenger RNAs for translational repression or, at lesser extent, degradation. miRNAs are widely expressed in tissues and organs and play fundamental roles in controlling cell proliferation, apoptosis, differentiation, cell migration, autophagy and metabolism. Uncontrolled expression of miRNAs has been associated with cancer progression, and miRNA up- or down-regulation has been linked to oncogenic and tumor-suppressive roles in cancers such as breast cancer, colorectal cancer, lung cancer, gastric cancer and glioblastoma. Altered expression of the miRNA mir-25 has been reported in many human malignant tumors, participating in various cellular processes accordingly with its broad range of potential mRNAs target. In the present review, we briefly discuss the mechanisms underlying miR-25-mediated tumorigenesis in six different human cancers and its possible future as a potential diagnostic and prognostic parameter as well as therapeutic target in clinical applications.

Roles of microRNAs in HIV-1 Replication and Latency

MicroRNAs (miRNAs) are non-coding RNA molecules, with sequence length of 19-24 nucleotides, which can induce mRNA degradation and regulate protein translation repression. Recently plenty of reports showed that miRNAs increase or decrease in the serum (circulating miRNAs) and in PBMC of Human immunodeficiency virus type 1 (HIV-1) infected individuals to affect the replication of HIV-1 through regulating HIV-1 proteins or HIV-1 replication related host factors. Many of miRNAs can suppress HIV-1 replication, but do not affect the integrated viral DNA. Low or no viral protein expression could result in a block of virus and its replication to induce HIV-1 latency, which is the great obstacle of the cure of HIV-1 infection. In the HIV-1 latency reservoir, the integrated provirus can reactivate under appropriate stimulus, which results in HIV-1 reproduction. Factors imply that cellular miRNAs may promote the establishment of HIV-1 latency. Further studies on the mechanisms of miRNAs affecting viral protein expression will provide new approaches to clear the viral reservoir.

Molecular targets of developmental exposure to bisphenol A in diabesity: a focus on endoderm-derived organs

Several studies associate foetal human exposure to bisphenol A (BPA) to metabolic/endocrine diseases, mainly diabesity. They describe the role of BPA in the disruption of pancreatic beta cell, adipocyte and hepatocyte functions. Indeed, the complexity of the diabesity phenotype is due to the involvement of different endoderm-derived organs, all targets of BPA. Here, we analyse this point delineating a picture of different mechanisms of BPA toxicity in endoderm-derived organs leading to diabesity. Moving from epidemiological data, we summarize the in vivo experimental data of the BPA effects on endoderm-derived organs (thyroid, pancreas, liver, gut, prostate and lung) after prenatal exposure. Mainly, we gather molecular data evidencing harmful effects at low-dose exposure, pointing to the risk to human health. Although the fragmentation of molecular data does not allow a clear conclusion to be drawn, the present work indicates that the developmental exposure to BPA represents a risk for endoderm-derived organs development as it deregulates the gene expression from the earliest developmental stages. A more systematic analysis of BPA impact on the transcriptomes of endoderm-derived organs is still missing. Here, we suggest in vitro toxicogenomics approaches as a tool for the identification of common mechanisms of BPA toxicity leading to the diabesity in organs having the same developmental origin.

Pesticide toxicogenomics across scales: in vitro transcriptome predicts mechanisms and outcomes of exposure in vivo

In vitro Omics analysis (i.e. transcriptome) is suggested to predict in vivo toxicity and adverse effects in humans, although the causal link between high-throughput data and effects in vivo is not easily established. Indeed, the chemical-organism interaction can involve processes, such as adaptation, not established in cell cultures. Starting from this consideration we investigate the transcriptomic response of immortalized thyrocytes to ethylenthiourea and chlorpyrifos. In vitro data revealed specific and common genes/mechanisms of toxicity, controlling the proliferation/survival of the thyrocytes and unrelated hematopoietic cell lineages. These results were phenotypically confirmed in vivo by the reduction of circulating T4 hormone and the development of pancytopenia after long exposure. Our data imply that in vitro toxicogenomics is a powerful tool in predicting adverse effects in vivo, experimentally confirming the vision described as Tox21c (Toxicity Testing in the 21st century) although not fully recapitulating the biocomplexity of a living animal.

RNA Viruses: RNA Roles in Pathogenesis, Coreplication and Viral Load

The review intends to present and recapitulate the current knowledge on the roles and importance of regulatory RNAs, such as microRNAs and small interfering RNAs, RNA binding proteins and enzymes processing RNAs or activated by RNAs, in cells infected by RNA viruses. The review focuses on how non-coding RNAs are involved in RNA virus replication, pathogenesis and host response, especially in retroviruses HIV, with examples of the mechanisms of action, transcriptional regulation, and promotion of increased stability of their targets or their degradation.

"Stockpile" of Slight Transcriptomic Changes Determines the Indirect Genotoxicity of Low-Dose BPA in Thyroid Cells

Epidemiological and experimental data highlighted the thyroid-disrupting activity of bisphenol A (BPA). Although pivotal to identify the mechanisms of toxicity, direct low-dose BPA effects on thyrocytes have not been assessed. Here, we report the results of microarray experiments revealing that the transcriptome reacts dynamically to low-dose BPA exposure, adapting the changes in gene expression to the exposure duration. The response involves many genes, enriching specific pathways and biological functions mainly cell death/proliferation or DNA repair. Their expression is only slightly altered but, since they enrich specific pathways, this results in major effects as shown here for transcripts involved in the DNA repair pathway. Indeed, even though no phenotypic changes are induced by the treatment, we show that the exposure to BPA impairs the cell response to further stressors. We experimentally verify that prolonged exposure to low doses of BPA results in a delayed response to UV-C-induced DNA damage, due to impairment of p21-Tp53 axis, with the BPA-treated cells more prone to cell death and DNA damage accumulation. The present findings shed light on a possible mechanism by which BPA, not able to directly cause genetic damage at environmental dose, may exert an indirect genotoxic activity.

Impairment of T cell development and acute inflammatory response in HIV-1 Tat transgenic mice

Immune activation and chronic inflammation are hallmark features of HIV infection causing T-cell depletion and cellular immune dysfunction in AIDS. Here, we addressed the issue whether HIV-1 Tat could affect T cell development and acute inflammatory response by generating a transgenic mouse expressing Tat in lymphoid tissue. Tat-Tg mice showed thymus atrophy and the maturation block from DN4 to DP thymic subpopulations, resulting in CD4⁺ and CD8⁺ T cells depletion in peripheral blood. In Tat-positive thymus, we observed the increased p65/NF-κB activity and deregulated expression of cytokines/chemokines and microRNA-181a-1, which are involved in T-lymphopoiesis. Upon LPS intraperitoneal injection, Tat-Tg mice developed an abnormal acute inflammatory response, which was characterized by enhanced lethality and production of inflammatory cytokines. Based on these findings, Tat-Tg mouse could represent an animal model for testing adjunctive therapies of HIV-1-associated inflammation and immune deregulation.

Cross-species toxicogenomic analyses and phenotypic anchoring in response to groundwater low-level pollution

Background

Comparison of toxicogenomic data facilitates the identification of deregulated gene patterns and maximizes health risk prediction in human.

Results

Here, we performed phenotypic anchoring on the effects of acute exposure to low-grade polluted groundwater using mouse and zebrafish. Also, we evaluated two windows of chronic exposure in mouse, starting in utero and at the end of lactation. Bioinformatic analysis of livers microarray data showed that the number of deregulated biofunctions and pathways is higher after acute exposure, compared to the chronic one. It also revealed specific profiles of altered gene expression in all treatments, pointing to stress response/mitochondrial pathways as major players of environmental toxicity. Of note, dysfunction of steroid hormones was also predicted by bioinformatic analysis and verified in both models by traditional approaches, serum estrogens measurement and vitellogenin mRNA determination in mice and zebrafish, respectively.

Conclusions

In our report, phenotypic anchoring in two vertebrate model organisms highlights the toxicity of low-grade pollution, with varying susceptibility based on exposure window. The overlay of zebrafish and mice deregulated pathways, more than single genes, is useful in risk identification from chemicals implicated in the observed effects.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1067) contains supplementary material, which is available to authorized users.

Cancer-associated CD43 glycoforms as target of immunotherapy

CD43 is a sialoglycosylated membrane protein that is involved in cell proliferation and differentiation. CD43 glycoforms that are recognized by the UN1 monoclonal antibody (mAb) were expressed in lymphoblastoid T-cell lines and solid tumors, such as breast, colon, gastric, and squamous cell lung carcinomas, while unexpressed in the normal counterparts. The cancer association of UN1/CD43 epitope suggested the possibility to use the UN1 mAb for tumor diagnosis and therapy. In this study, we show that the UN1 mAb was endowed with antitumor activity in vivo because its passive transfer inhibited the growth of UN1-positive HPB-ALL lymphoblastoid T cells in mice. Furthermore, we demonstrate that tumor inhibition was due to UN1 mAb-dependent natural killer-mediated cytotoxicity. By screening a phage-displayed random peptide library, we identified the phagotope 2/165 as a mimotope of the UN1 antigen, as it harbored a peptide sequence that was specifically recognized by the UN1 mAb and inhibited the binding of the UN1 mAb to UN1-positive tumor cells. On the basis of sequence homology with the extracellular region of CD43 (amino acids 64 to 83), the 2/165 peptide sequence was likely mimicking the protein core of the UN1/CD43 epitope. When used as vaccine in mice, the 2/165 phagotope raised antibodies against the UN1/CD43 antigen, indicating that the 2/165 phagotope mimicked the UN1 antigen structure, and could represent a novel immunogen for cancer immunotherapy. These findings support the feasibility of using monoclonal antibodies to identify cancer-associated mimotopes for immunotherapy.

miR-155 is up-regulated in primary and secondary glioblastoma and promotes tumour growth by inhibiting GABA receptors

An altered expression of microRNAs (miRNAs) contributes both to the development of cancer and to the progression of the disease. Malignant tumours and tumour cell lines have widespread deregulated expressions of miRNAs compared to normal tissues. In this study, we investigated the expression profiles of 340 mammalian miRNAs in 93 cases of multiform glioblastoma (primary and secondary glioblastoma tumours), by means of DNA microarrays. We show that the expression profiles of 10 miRNAs can distinguish primary from secondary glioblastoma types. Moreover, we found elevated miR-155 levels in primary and secondary glioblastoma tissues as well as in glioblastoma primary cultures. We hypothesised that γ-aminobutyric acid A receptor 1 (GABRA1) is a miR-155 target, and studied the correlation between miR-155 up-regulation and the GABRA1 protein in cultured glioblastoma cells by miRNA silencing. We show that a decrease in miR-155 expression to normal levels restores the expression of GABRA1, making glioblastoma cells sensitive to signals that inhibit cell proliferation mediated by GABRA1. In conclusion, the expression patterns of different miRNAs characterise primary and secondary glioblastomas. The aberrant overexpression of miR-155 contributes to the malignant phenotype of glioblastoma cells removing growth inhibition.

FKBP51 and the NF-κB regulatory pathway in cancer

Constitutive activation of NF-κB occurs in a significant percentage of human cancers. Genetic abnormalities of tumors often enhance normal NF-κB signaling. Chronic inflammation is also associated with constitutive NF-κB activation and increases the risk of cancer. Aberrant NF-κB activation favors cellular transformation, sustains cancer survival, and contributes to tumor invasion. Strategies to inhibit NF-κB represent a promising therapeutic option against cancer. In the last decade, several studies point to the large immunophilin FKBP51 as an important element for the control of NF-κB activation in human neoplasia. This article is an overview of the causes of aberrant NF-κB regulation in cancer and highlights recent papers that implicate FKBP51 in such deregulation.

Non-coding RNAs change their expression profile after Retinoid induced differentiation of the promyelocytic cell line NB4

Background

The importance of non-coding RNAs (ncRNAs) as fine regulators of eukaryotic gene expression has emerged by several studies focusing on microRNAs (miRNAs). miRNAs represent a newly discovered family of non coding-RNAs. They are thought to be crucial players of human hematopoiesis and related tumorigenesis and to represent a potential tool to detect the early stages of cancer. More recently, the expression regulation of numerous long ncRNAs has been linked to cell growth, differentiation and cancer although the molecular mechanism of their function is still unknown.

NB4 cells are promyelocytic cells that can be induced to differentiation upon retinoic acid (ATRA) treatment and represent a feasible model to study changes of non coding RNAs expression between cancer cells and their terminally differentiated counterpart.

Findings

we screened, by microarray analysis, the expression of 243 miRNAs and 492 human genes transcribing for putative long ncRNAs different from miRNAs in NB4 cells before and after ATRA induced differentiation. Our data show that 8 miRNAs, and 58 long ncRNAs were deregulated by ATRA induced NB4 differentiation.

Conclusion

our data suggest that ATRA-induced differentiation lead to deregulation of a large number of the ncRNAs that can play regulatory roles in both tumorigenesis and differentiation.

Computational analysis and in vivo validation of a microRNA encoded by the IBTK gene, a regulator of B-lymphocytes differentiation and survival

MicroRNAs (miRNAs) are small single-stranded RNA molecules that play an essential role in the regulation of gene expression and cell physiology. Gene rearrangements occurring in the miRNA sequence are associated with cancer. The IBTK genetic locus is located in the genomic sequence 6q14.1 that undergoes chromosomal aberration in lymphoproliferative disorders. The IBTK gene encodes the proteins IBtk-alpha, beta and gamma that regulate the B cell receptor signalling through Bruton's tyrosine kinase, which promotes B cell survival and differentiation. Pro-MirII-based analysis predicted four precursors of microRNAs (pre-miR) encoded by introns 17, 21, 26 and the 3' un-translated region of the IBTK gene. Pre-miR-IBTK3, which was encoded by intron 26, was the effective substrate of RNase III Dicer in vitro as well as the precursor of an IBtk miRNA generated in vivo. By CLUSTALW-based analysis, pre-miR-IBTK3 homologues were found in Pan troglodytes, Pongo pygmaeus and Macaca mulatta, suggesting an evolutionary conserved function in primates.

Epstein-Barr virus latent membrane protein 1 trans-activates miR-155 transcription through the NF-kappaB pathway

The Epstein–Barr virus (EBV)-encoded latent membrane protein-1 (LMP1), a functional homologue of the tumor necrosis factor receptor family, substantially contributes to EBV's oncogenic potential by activating nuclear factor-κB (NF-κB). miR-155 is an oncogenic miRNA critical for B-cell maturation and immunoglobulin production in response to antigen. We report that miR-155 expression is much higher in EBV-immortalized B cells than in EBV-negative B cells. LMP1, but not LMP2, up-regulated the expression of miR-155, when transfected in EBV-negative B cells. We analyzed two putative NF-κB binding sites in the miR-155 promoter; both sites recruited NF-κB complex, in nuclear extract from EBV-immortalized cells. The exogenous expression of LMP1, in EBV-negative background, is temporally correlated to induction of p65 with binding on both NF-κB sites and with miR-155 overexpression. The induction of p65 binding together with increased RNA polymerase II binding, confirms that LMP1-mediated activation of miR-155 occurs transcriptionally. In reporter assays, miR-155 promoter lacking NF-κB binding sites was no longer activated by LMP1 expression and an intact AP1 site is needed to attain maximum activation. Finally, we demonstrate that LMP1-mediated activation of miR-155 in an EBV-negative background correlates with reduction of protein PU.1, which is a possible miR target.

Non-protein coding RNA biomarkers and differential expression in cancers: a review

Background

In these years a huge number of human transcripts has been found that do not code for proteins, named non-protein coding RNAs. In most cases, small (miRNAs, snoRNAs) and long RNAs (antisense RNA, dsRNA, and long RNA species) have many roles, functioning as regulators of other mRNAs, at transcriptional and post-transcriptional level, and controlling protein ubiquitination and degradation. Various species of npcRNAs have been found differentially expressed in different types of cancer. This review discusses the published data and new results on the expression of a subset of npcRNAs.

Conclusion

These results underscore the complexity of the RNA world and provide further evidence on the involvement of functional RNAs in cancer cell growth control.

TEF-1 and C/EBPbeta are major p38alpha MAPK-regulated transcription factors in proliferating cardiomyocytes

p38 MAPKs (mitogen-activated protein kinases) play important roles in the regulation of cellular responses to environmental stress. Recently, this signalling pathway has also been implicated in the regulation of processes unrelated to stress, for example, in T lymphocytes and cardiomyocytes. In order to identify molecular targets responsible for the housekeeping functions of p38 MAPKs, we have analysed the differences in the transcriptomes of normally proliferating wild-type and p38alpha knockout immortalized embryonic cardiomyocytes. Interestingly, many potential components of the myocardium extracellular matrix were found to be upregulated in the absence of p38alpha. Further analysis of the microarray data identified TEF-1 (transcriptional enhancer factor-1), a known regulator of heart-specific gene expression, and C/EBPbeta (CCAAT/enhancer-binding protein beta), as the two transcription factors the binding sites of which were most enriched in the promoters of p38alpha-regulated genes. We have focused on the study of the extracellular matrix component COL1A1 (alpha1 chain of type I collagen) and found evidence for the involvement of both TEF-1 and C/EBPbeta in the p38alpha-dependent inhibition of COL1A1 transcription. Our data therefore show that p38 MAPKs regulate TEF-1 and C/EBPbeta transcriptional activity in the absence of environmental stress and suggests a role for p38alpha in the expression of extracellular matrix components that maintain organ architecture.

Freehand three-dimensional echocardiographic evaluation of the effect of telmisartan compared with hydrochlorothiazide on left ventricular mass in hypertensive patients with mild-to-moderate hypertension: a multicentre study

Antihypertensive efficacy, effects on left ventricular mass index (LVMI) and tolerability of telmisartan, an angiotensin II receptor blocker, were compared with those of hydrochlorothiazide (HCTZ). Adult patients with mild-to-moderate hypertension and an optimal acoustic window by two-dimensional echocardiography were randomised at baseline to 12 months' double-blind, once-daily treatment with telmisartan 80 mg or HCTZ 25 mg. Two-dimensional echocardiography and freehand precordial three-dimensional echocardiography and 24-h ambulatory blood pressure monitoring were performed at baseline and after treatment. Of the 41 telmisartan group patients and 28 HCTZ group patients, 40 and 25, respectively, completed the study. Following treatment, 24-h mean SBP (telmisartan 157 +/- 11 vs 133 +/- 7 mmHg, P<0.001; HCTZ 154 +/- 10 vs 144 +/- 11 mmHg, P<0.003) and DBP (telmisartan 96 +/- 6 vs 83 +/- 5 mmHg, P<0.001; HCTZ 95 +/- 7 vs 87 +/- 8 mmHg, P<0.003) were significantly reduced. Telmisartan produced significantly greater 24-h mean SBP and DBP reductions than HCTZ (P<0.001). LVMI was significantly reduced by telmisartan (141 +/- 16 vs 125 +/- 19 g/m2, P<0.001), but not by HCTZ (139 +/- 20 vs 135 +/- 22 g/m(2)). Incidences of adverse events in both the treatment groups were low; two cases of hypokalaemia occurred with HCTZ. In conclusion, telmisartan 80 mg was well tolerated and significantly reduced SBP, DBP and LVMI after 12 months' treatment compared with HCTZ.

A GFP-based system to uncouple mRNA transport from translation in a single living neuron

An inducible fluorescent system based on GFP is presented that allows for the uncoupling of dendritic mRNA transport from subsequent protein synthesis at the single cell level. The iron-responsive element (IRE) derived from ferritin mRNA in the 5'-UTR of the GFP reporter mRNA renders translation of its mRNA dependent on iron. The addition of the full-length 3'-UTR of the Ca(2+)/calmodulin-dependent protein kinase II alpha (CaMKIIalpha) after the stop codon of the GFP reading frame targets the reporter mRNA to dendrites of transfected fully polarized hippocampal neurons. As we show by time-lapse videomicroscopy, iron specifically turns on GFP reporter protein synthesis in a single transfected hippocampal neuron. We investigate whether GFP expression is affected--in addition to iron--by synaptic activity. Interestingly, synaptic activity has a clear stimulatory effect. Most importantly, however, this activity-dependent protein synthesis is critically dependent on the presence of the full-length 3'-UTR of CaMKIIalpha confirming that this sequence contains translational activation signals. The IRE-based system represents a new convenient tool to study local protein synthesis in mammalian cells where mRNA localization to a specific intracellular compartment occurs.

Isolation and characterization of Staufen-containing ribonucleoprotein particles from rat brain

Localized mRNAs are thought to be transported in defined particles to their final destination. These particles represent large protein complexes that may be involved in recognizing, transporting, and anchoring localized messages. Few components of these ribonucleoparticles, however, have been identified yet. We chose the strategy to biochemically enrich native RNA-protein complexes involved in RNA transport to identify the associated RNAs and proteins. Because Staufen proteins were implicated in intracellular RNA transport, we chose mammalian Staufen proteins as markers for the purification of RNA transport particles. Here, we present evidence that Staufen proteins exist in two different complexes: (i) distinct large, ribosome- and endoplasmic reticulum-containing granules preferentially found in the membrane pellets during differential centrifugation and (ii) smaller particles in the S100 from rat brain homogenates. On gel filtration of the S100, we identified soluble 670-kDa Staufen1-containing and 440-kDa Staufen2-containing particles. They do not cofractionate with ribosomes and endoplasmic reticulum but rather coenrich with kinesin heavy chain. Furthermore, the fractions containing the Staufen1 particles show a 15-fold enrichment of mRNAs compared with control fractions. Most importantly, these fractions are highly enriched in BC1, and, to a lesser extent, in the alpha-subunit of the Ca(2+)/calmodulin-dependent kinase II, two dendritically localized RNAs. Finally, both RNAs colocalize with Staufen1-hemagglutinin in particles in dendrites of transfected hippocampal neurons. We therefore propose that these Staufen1-containing particles may represent RNA transport intermediates that are in transit to their final destination within neurons.

Relationship between vaccinia virus intracellular cores, early mRNAs, and DNA replication sites

Virus assembly, a late event in the life cycle of vaccinia virus (VV), is preceded by a number of steps that all occur in the cytoplasm of the infected host cell: virion entry, delivery of the viral core into the cytoplasm, and transcription from these cores of early mRNAs, followed by the process of DNA replication. In the present study the quantitative and structural relationships between these distinct steps of VV morphogenesis were investigated. We show that viral RNA and DNA synthesis increases linearly with increasing amounts of incoming cores. Moreover, at multiplicities of infection that result in 10 to 40 cores per cell, an approximately 1:1 ratio between cores and sites of DNA replication exists, suggesting that each core is infectious. We have shown previously that VV early mRNAs collect in distinct granular structures that recruit components of the host cell translation machinery. Strikingly, these structures appeared to form some distance away from intracellular cores (M. Mallardo, S. Schleich, and J. Krijnse Locker, Mol. Biol. Cell 12:3875-3891, 2001). In the present study the intracellular locations of the sites of early mRNA accumulation and those of the subsequent process of DNA replication were compared. We show that these are distinct structures that have different intracellular locations. Finally, we study the fate of the parental DNA after core uncoating. By electron microscopy, cores were found close to membranes of the endoplasmic reticulum (ER) and the parental DNA, once it had left the core, appeared to associate preferentially with the cytosolic side of those membranes. Since we have previously shown that the process of DNA replication occurs in an ER-enclosed cytosolic "subcompartment" (N. Tolonen, L. Doglio, S. Schleich, and J. Krijnse Locker, Mol. Biol. Cell 12:2031-2046, 2001), the present data suggest that the parental DNA is released into the cytosol and associates with the same membranes where DNA replication is subsequently initiated. The combined data are discussed with respect to the cytosolic organization of VV morphogenesis.

Microtubule-dependent organization of vaccinia virus core-derived early mRNAs into distinct cytoplasmic structures

Vaccinia virus (vv) early transcription can be reconstituted in vitro from purified virions; in this assay mRNAs are made inside the viral core and subsequently extruded. Although the in vitro process has been extensively characterized, relatively little is known about vv early transcription in vivo. In the present study the fate of vv early mRNAs in infected HeLa cells was followed by BrUTP transfection and confocal and electron microscopy. The extruded vv early mRNAs were found to be organized into unique granular cytoplasmic structures that reached a size up to 1 microm. By EM these structures appeared as amorphous electron-dense cytoplasmic aggregates that were surrounded by ribosomes. Confocal images showed that the RNA structures were located some distance away from intracellular cores and that both structures appeared to be aligned on microtubules (MTs), implying that MT tracks connected mRNAs and cores. Accordingly, intact MTs were found to be required for the typical punctate organization of viral mRNAs. Biochemical evidence supported the notion that vv mRNAs were MT associated and that MT depletion severely affected viral (but not cellular) mRNA synthesis and stability. By confocal microscopy the viral mRNA structures appeared to be surrounded by molecules of the translation machinery, showing that they were active in protein synthesis. Finally, our data suggest a role for a MT and RNA-binding viral protein of 25 kDa (gene L4R), in mRNA targeting away from intracellular cores to their sites of cytoplasmic accumulation.

Potent and stable attenuation of live-HIV-1 by gain of a proteolysis-resistant inhibitor of NF-kappaB (IkappaB-alphaS32/36A) and the implications for vaccine development

Live-attenuated human immunodeficiency viruses (HIVs) are candidates for Acquired Immunodeficiency Syndrome (AIDS) vaccine. Based on the simian immunodeficiency virus (SIV) model for AIDS, loss-of-function (e.g. deletion of accessory genes such as nef) has been forwarded as a primary approach for creating enfeebled, but replication-competent, HIV-1/SIV. Regrettably, recent evidence suggests that loss-of-function alone is not always sufficient to prevent the emergence of virulent mutants. New strategies that attenuate via mechanisms distinct from loss-of-function are needed for enhancing the safety phenotype of viral genome. Here, we propose gain-of-function to be used simultaneously with loss-of-function as a novel approach for attenuating HIV-1. We have constructed an HIV-1 genome carrying the cDNA of a proteolysis-resistant nuclear factor-kappaB inhibitor (IkappaB-alphaS32/36A) in the nef region. HIV-1 expressing IkappaB-alphaS32/36A down-regulates viral expression and is highly attenuated in both Jurkat and peripheral blood mononuclear cells. We provide formal proof that the phenotypic and attenuating characteristics of IkappaB-alphaS32/36A permit its stable maintenance in a live, replicating HIV-1 despite 180 days of forced ex vivo passaging in tissue culture. As compared with other open-reading frames embedded into HIV/SIV genome, this degree of stability is unprecedented. Thus, IkappaB-alphaS32/36A offers proof-of-principle that artifactually gained functions, when used to attenuate the replication of live HIV-1, can be stable. These findings illustrate gain-of-function as a feasible strategy for developing safer live-attenuated HIVs to be tested as candidates for AIDS vaccine.

HIV-1 Tat induces the expression of the interleukin-6 (IL6) gene by binding to the IL6 leader RNA and by interacting with CAAT enhancer-binding protein beta (NF-IL6) transcription factors

Human immunodeficiency virus type 1 (HIV-1) infection is associated with severe psoriasis, B cell lymphoma, and Kaposi's sarcoma. A deregulated production of interleukin-6 (IL6) has been implicated in the pathogenesis of these diseases. The molecular mechanisms underlying the abnormal IL6 secretion of HIV-1-infected cells may include transactivation of the IL6 gene by HIV-1. Here we report the molecular mechanisms of Tat activity on the expression of the IL6 gene. By using 5' deletion mutants of pIL6Pr-CAT and using IL6:HIV-1-LTR hybrid constructs where discrete regions of the IL6 promoter replaced the TAR sequence in HIV-1 LTR, we identified a short sequence of the 5'-untranslated region of the IL6 mRNA that is required for Tat to trans-activate the IL6 promoter. This sequence acquires a stem-loop structure and includes a UCU sequence that binds to Tat and is necessary for full trans-activation. In addition, we provide the evidence that Tat can function by enhancing the CAAT enhancer-binding protein (C/EBP) DNA binding activity and is able to complex with in vitro translated C/EBPbeta, which is a major mediator of IL6 promoter function. By using the yeast two-hybrid system and immunoprecipitation, we observed that the interaction of Tat with C/EBP proteins also occurred in vivo. The data are consistent with the possibility that Tat may function on heterologous genes by interacting with RNA structures possibly present in a large number of cellular and viral genes. In addition, Tat may function by protein-protein interactions, leading to the generation of heterodimers with specific transcription factors.