Papers by valeria di dato
Microorganisms, Dec 11, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Marine environmental research, Apr 1, 2024
Prostaglandins (Pgs) are eicosanoid lipid mediators detected in all vertebrates, in some marine i... more Prostaglandins (Pgs) are eicosanoid lipid mediators detected in all vertebrates, in some marine invertebrates, macroalgae and in diatoms, a class of eukaryotic microalgae composing the phytoplankton. The enzymes involved in the Pgs pathway were found to be differentially expressed in two strains of the diatom Skeletonema marinoi, named FE7 and FE60, already known to produce different levels of oxylipins, a class of secondary metabolites involved in the defence of diatoms against copepod predation, with FE7 being higher producer than FE60. In the present study we investigated the response of genes involved in the production of oxylipins and Pgs, evaluating their expression after the exposure to the copepod Temora stylifera. Our results highlighted a grazer feeding preference for FE60, the strain having low oxylipins content and reduced expression of Pgs enzymes, and an impact on the gene expression of the enzymes involved in oxylipins (i.e. lipoxygenase) and Pgs (i.e. cyclooxygenase) biosynthesis, especially in FE7. A time course evaluation of the gene expression over 24 h showed an upregulation of the essential enzyme in the Pgs pathway, the cyclooxygenase, in FE60 after 6 h of exposure to the grazer, differently from FE7 where no upregulation of gene expression in the presence of copepods was revealed. These results provide preliminary indications regarding the existence of a complex involvement of the Pgs pathway in the prey-predator interaction that requires further investigations.
Data from The Quassinoid Derivative NBT-272 Targets Both the AKT and ERK Signaling Pathways in Embryonal Tumors
The quassinoid analogue NBT-272 has been reported to inhibit MYC, thus warranting a further effor... more The quassinoid analogue NBT-272 has been reported to inhibit MYC, thus warranting a further effort 7to better understand its preclinical properties in models of embryonal tumors (ET), a family of childhood malignancies sharing relevant biological and genetic features such as deregulated expression of MYC oncogenes. In our study, NBT-272 displayed a strong antiproliferative activity in vitro that resulted from the combination of diverse biological effects, ranging from G1/S arrest of the cell cycle to apoptosis and autophagy. The compound prevented the full activation of both eukaryotic translation initiation factor 4E (eIF4E) and its binding protein 4EBP-1, regulating cap-dependent protein translation. Interestingly, all responses induced by NBT-272 in ET could be attributed to interference with 2 main proproliferative signaling pathways, that is, the AKT and the MEK/extracellular signal-regulated kinase pathways. These findings also suggested that the depleting effect of NBT-272 on MYC protein expression occurred via indirect mechanisms, rather than selective inhibition. Finally, the ability of NBT-272 to arrest tumor growth in a xenograft model of neuroblastoma plays a role in the strong antitumor activity of this compound, both in vitro and in vivo, with its potential to target cell-survival pathways that are relevant for the development and progression of ET. Mol Cancer Ther; 9(12); 3145–57. ©2010 AACR.
Clinical & Experimental Metastasis, Apr 7, 2012
Prostate and breast cancer are major causes of death worldwide, mainly due to patient relapse upo... more Prostate and breast cancer are major causes of death worldwide, mainly due to patient relapse upon disease recurrence through formation of metastases. Chemokines are small proteins with crucial roles in the immune system, and their regulation is finely tuned in early inflammatory responses. They are key molecules during inflammatory processes, and many studies are focusing on their regulatory functions in tumor growth and angiogenesis during metastatic cell seeding and spreading. Bindarit is an anti-inflammatory indazolic derivative that can inhibit the synthesis of MCP-1/CCL2, with a potential inhibitory function in tumor progression and metastasis formation. We show here that in vitro, bindarit can modulate cancercell proliferation and migration, mainly through negative regulation of TGF-b and AKT signaling, and it can impair the NF-jB signaling pathway through enhancing the expression of the NF-jB inhibitor IkB-a. In vivo administration of bindarit results in impaired metastatic disease in prostate cancer xenograft mice (PC-3M-Luc2 cells injected intra-cardially) and impairment of local tumorigenesis in syngeneic Balb/c mice injected under the mammary gland with murine breast cancer cells (4T1-Luc cells). In addition, bindarit treatment significantly decreases the infiltration of tumor-associated macrophages and myeloid-derived suppressor cells in 4T1-Luc primary tumors. Overall, our data indicate that bindarit is a good candidate for new therapies against prostate and breast tumorigenesis, with an action through impairment of inflammatory cell responses during formation of the tumor-stroma niche microenvironment.
The biosynthesis and metabolism of prostaglandins in microalgae
Elsevier eBooks, 2022
Scientific Reports, Jul 9, 2019
Diatoms are phytoplankton eukaryotic microalgae that are widely distributed in the world's oceans... more Diatoms are phytoplankton eukaryotic microalgae that are widely distributed in the world's oceans and are responsible for 20-25% of total carbon fixation on the planet. Using transcriptome sequencing here we show for the first time that the ubiquitous diatom Thalassiosira rotula expresses biosynthetic pathways that potentially lead to the synthesis of interesting secondary metabolites with pharmaceutical applications such as polyketides, prostaglandins and secologanin. We also show that these pathways are differentially expressed in conditions of silica depletion in comparison with standard growth conditions. Diatoms are a major group of eukaryotic microalgae in the phytoplankton widely distributed in the world's oceans, and capable through photosynthesis of fixing about 20-25% of the total carbon on the planet 1. Their worldwide distribution is supported by a molecular tool-kit (M-T) that allows them to adapt to different conditions through the perception of environmental cues and the control of competitors and grazers 2-5. Some of the metabolites which are part of this M-T have already been identified as having potential applications as pharmaceuticals or cosmeceuticals 6. Nevertheless, the full potential of marine diatoms still needs to be unlocked. One way to unlock this potential is to expose diatoms to stressful conditions to force changes in their metabolism and activate biosynthetic pathways inducing the production of secondary metabolites. One of the stressful conditions to promote such changes is nutrient depletion during microalgae growth. For example, phosphorus (P) deficiency in Thalassiosira rotula induces a remodelling of the transcriptome including changes in cellular P allocation patterns, enzyme activity and lipid composition, whereas nitrogen (N) deprivation reduces primary carbon metabolism leading to accumulation of lipids 7. In addition to P and N, also carbon deprivation, independently from the light intensity (30, 300 or 1000 μmol photon m −2 s −1), induces a rearrangement of the Carbon Concentration Mechanisms (CCM) toward the synthesis of pyruvate 8,9 reorienting the carbon metabolism toward lipid accumulation. A similar remodelling of metabolic pathways occurs in conditions of silica depletion 10. Diatoms require silica (Si) to generate the intricate frustules that surround the cell and allow the entrance of light to the chloroplasts and the transport of gases and solutes. The silica cell wall is believed to provide an ecological advantage over other phytoplankton groups due to its mechanical strength that protects diatoms against grazers. Deprivation of Si arrests progression of cell cycle events, such as cell division and DNA replication, attesting the importance of silica in the diatom life cycle 11. Here we analyse the transcriptome of the diatom Thalassiosira rotula, isolated from the Gulf of Naples in the Mediterranean Sea, comparing cultures grown in normal condition (CTR) versus cultures grown in conditions of stress such as silica depletion (STRESS). Our analysis shows that this diatom species has the potential to produce new metabolites, i.e. secologanin, polyketides and prostaglandins, the related pathways of which are differentially expressed under this stress condition. We experimentally confirmed the expression of these pathways identified in the newly sequenced transcriptome of our clone and also compared their expression with those from other T. rotula clones, grown under different stress conditions and sequenced in the Marine Microbial Eukaryotic Transcriptome Sequencing Project (MMETSP) 12 supported by the Moore Foundation. Our study also confirms that the identified pathways are actually present in the T. rotula genome and do not derive from bacteria commonly associated with diatom cells.
Molecular Endocrinology, Nov 1, 2004
We previously demonstrated that transcription of the rat sodium/iodide symporter (NIS) gene is re... more We previously demonstrated that transcription of the rat sodium/iodide symporter (NIS) gene is regulated by NUE, an upstream enhancer located between nucleotides ؊2264 and ؊2495 of the 5flanking region. To elucidate the mechanism of TSH/cAMP-mediated regulation of NIS gene expression, we have characterized the putative cAMP response element (CRE)/activator protein (AP)-1 site (termed NUC) that is closely located between the two Pax-8 (paired box domain transcription factor-8) binding sites within NUE. In two different approaches using either gel supershift analyses or dominant-negative inhibitors of b-Zip molecules, we have shown that NUC can be recognized by several members of the AP-1 and CREB family transcription factors that modulate the transcriptional activity of NUE. Using tethered dimers of b-Zip molecules, we have also demonstrated that specific homo-or heterodimers of AP-1 can synergistically stimulate NUE activity in concert with Pax-8. To demonstrate further that NUC is a bona fide CRE, we made an artificial promoter with the five-time tandem repeat of this sequence (5xNUC). In comparison to the canonical CRE (5xCRE), 5xNUC manifested greater transcriptional activity and broader response to cAMP signaling. Hence, we postulate that the significance of this evolutionally conserved CRE-like site may lie in its broader cell type specificity.
with 13-cis-RA relative to ATRA. 7 High levels of either ATRA or 13-cis-RA can cause arrest of ce... more with 13-cis-RA relative to ATRA. 7 High levels of either ATRA or 13-cis-RA can cause arrest of cell growth and morphological differentiation of human NB cell lines. 7 A phase III, randomized trial showed that high-dose, pulse therapy with 13-cis-RA after completion of intensive chemoradiotherapy (with or without autologous bone-marrow transplantation) significantly improves event-free survival for patients with high-risk NB. The retinoic acids affect NB differentiation through transcriptional regulation of genes that are either directly involved in the differentiation process or that control the differentiation process. 11-13 Gene expression profiling on NB specimens has identified molecular signatures for high-risk and low-risk tumors 14-16 and novel prognostic markers. 17-19 We investigated the expression profile of NB cell lines induced to differentiation using ATRA to identify early target genes that are involved in this transcriptional network. Through this screening, we identified the Mpped2 gene (also known as c11orf8 or 239FB), which shows high expression in differentiated NB cells. The Mpped2 gene is located on human chromosome 11p13 between the FSHB and PAX6 genes in a region that is also associated with Wilms' tumor, aniridia, genitourinary anomalies and mental retardation (WAGR syndrome). 20,21 Mpped2 mRNA is predominantly expressed in fetal brain, 22
Scientific Reports, Mar 25, 2020
prostaglandins (pGs) are hormone-like mediators in many physiological and pathological processes ... more prostaglandins (pGs) are hormone-like mediators in many physiological and pathological processes that are present in all vertebrates, in some terrestrial and aquatic invertebrates, and have also been identified in some macroalgae. They have recently been reported also in marine microalgae but their role as chemical mediators is largely unknown. Here we studied the expression pattern of the PG biosynthetic pathway during different growth phases of the centric diatom Thalassiosira rotula and assessed the release of PGs in the surrounding environment for the first time. We show that enzymes responsible for PGs formation such as cyclooxygenase, prostaglandin E synthase 2-like and prostaglandin F synthase are mainly expressed at the end of the exponential phase and that PGs are released especially during the stationary and senescent phases, suggesting a possible signaling function for these compounds. Phylogenetic analysis of the limiting enzyme, COX, indicate the presence in diatoms of more than one enzyme related to the oxidative metabolism of fatty acids belonging to the peroxidase-cyclooxygenase superfamily. These findings suggest a more complex evolution and diversity of metabolic pathways leading to the synthesis of lipid mediators in diatoms. Arachidonic acid (ARA), eicosapentaenoic acid (EPA), eicosatrienoic acid (ETrA) and docosahexaenoic acid (DHA) are polyunsaturated fatty acids that are physiologically important for animals at all taxonomic levels, including humans. EPA and DHA contribute to the healthy functioning of the cardiovascular system 1 and are precursors of important classes of fatty acid-derivatives playing multiple signaling roles in inflammation and immune responses, platelet aggregation and tumor growth 2,3. Among these, the inflammation process is one of the most important mechanisms adopted by organisms in response to various external stimuli 3. Inflammation involves a complex interplay of signaling molecules whose final goal is to restore the healthy status of a cell or tissue. Consequences of sustained inflammation are indeed the development of serious diseases such as cancer and autoimmune disorders 4. Included in the eicosanoids are prostaglandins (PGs) synthesized principally from arachidonic acid (ARA) in animals, but also from EPA and ETrA, through the enzymatic route initiated by cyclooxygenase (COXs) enzymes 5. PGs are molecules with a hormone-like behavior playing a prominent role in many physiological processes that have been principally studied in animals 3. The expression of the COXs enzymes is mandatory for their synthesis. COXs exist in two isoforms that differ for their subcellular localization and for their expression timing. COX-1 is located in the endoplasmic reticulum and is constitutively expressed at constant levels in many tissues unless external cues, such as tumor promoting factor, cytokine and growth factor, induce an increase in its expression level. COX-2 is the inducible form, which is not detectable unless a trigger similar to those that stimulate COX-1 expression occurs. COX-2 is located in the nuclear envelope and appears to be a target for cancer therapy 6. PGs synthesis, in mammals, is initiated by phospholipases (PLAs), a family of enzymes that hydrolyze membrane phospholipids liberating the precursors, ARA, EPA, and ETrA. These are rapidly converted, through cyclization and inclusion of molecular oxygen, into the unstable metabolite PGG 2 by the action of COXs enzymes that subsequently reduce it into PGH 2. The PGH 2 is then transformed into the ultimate prostaglandin E 2 , D 2 , F 2α , prostacyclin or tromboxanes by the successive action of PGE, PGD, PGF, prostacyclin and tromboxanes A
BMC Genomics, May 14, 2010
Background: The molecular mechanisms leading to a fully differentiated thyrocite are still object... more Background: The molecular mechanisms leading to a fully differentiated thyrocite are still object of intense study even if it is well known that thyroglobulin, thyroperoxidase, NIS and TSHr are the marker genes of thyroid differentiation. It is also well known that Pax8, TTF-1, Foxe1 and Hhex are the thyroid-enriched transcription factors responsible for the expression of the above genes, thus are responsible for the differentiated thyroid phenotype. In particular, the role of Pax8 in the fully developed thyroid gland was studied in depth and it was established that it plays a key role in thyroid development and differentiation. However, to date the bases for the thyroid-enriched expression of this transcription factor have not been unraveled yet. Here, we report the identification and characterization of a functional thyroidspecific enhancer element located far upstream of the Pax8 gene. Results: We hypothesized that regulatory cis-acting elements are conserved among mammalian genes. Comparison of a genomic region extending for about 100 kb at the 5'-flanking region of the mouse and human Pax8 gene revealed several conserved regions that were tested for enhancer activity in thyroid and non-thyroid cells. Using this approach we identified one putative thyroid-specific regulatory element located 84.6 kb upstream of the Pax8 transcription start site. The in silico data were verified by promoter-reporter assays in thyroid and non-thyroid cells. Interestingly, the identified far upstream element manifested a very high transcriptional activity in the thyroid cell line PC Cl3, but showed no activity in HeLa cells. In addition, the data here reported indicate that the thyroid-enriched transcription factor TTF-1 is able to bind in vitro and in vivo the Pax8 far upstream element, and is capable to activate transcription from it. Conclusions: Results of this study reveal the presence of a thyroid-specific regulatory element in the 5' upstream region of the Pax8 gene. The identification of this regulatory element represents the first step in the investigation of upstream regulatory mechanisms that control Pax8 transcription during thyroid differentiation and are relevant to further studies on Pax8 as a candidate gene for thyroid dysgenesis.
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