Publications by authors named "Raffaella Pacchiana"

32 Publications

Extracellular Matrix Composition Modulates the Responsiveness of Differentiated and Stem Pancreatic Cancer Cells to Lipophilic Derivate of Gemcitabine.

Int J Mol Sci 2020 Dec 22;22(1). Epub 2020 Dec 22.

Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70126 Bari, Italy.

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Gemcitabine (GEM) is used as the gold standard drug in PDAC treatment. However, due to its poor efficacy, it remains urgent to identify novel strategies to overcome resistance issues. In this context, an intense stroma reaction and the presence of cancer stem cells (CSCs) have been shown to influence PDAC aggressiveness, metastatic potential, and chemoresistance.

Methods: We used three-dimensional (3D) organotypic cultures grown on an extracellular matrix composed of Matrigel or collagen I to test the effect of the new potential therapeutic prodrug 4-(N)-stearoyl-GEM, called C18GEM. We analyzed C18GEM cytotoxic activity, intracellular uptake, apoptosis, necrosis, and autophagy induction in both Panc1 cell line (P) and their derived CSCs.

Results: PDAC CSCs show higher sensitivity to C18GEM treatment when cultured in both two-dimensional (2D) and 3D conditions, especially on collagen I, in comparison to GEM. The intracellular uptake mechanisms of C18GEM are mainly due to membrane nucleoside transporters' expression and fatty acid translocase CD36 in Panc1 P cells and to clathrin-mediated endocytosis and CD36 in Panc1 CSCs. Furthermore, C18GEM induces an increase in cell death compared to GEM in both cell lines grown on 2D and 3D cultures. Finally, C18GEM stimulated protective autophagy in Panc1 P and CSCs cultured on 3D conditions.

Conclusion: We propose C18GEM together with autophagy inhibitors as a valid alternative therapeutic approach in PDAC treatment.
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http://dx.doi.org/10.3390/ijms22010029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7792955PMC
December 2020

Mutant p53-Associated Molecular Mechanisms of ROS Regulation in Cancer Cells.

Biomolecules 2020 02 26;10(3). Epub 2020 Feb 26.

Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, 37134 Verona, Italy.

The tumor suppressor gene is the most frequently altered gene in tumors and an increasing number of studies highlight that mutant p53 proteins can acquire oncogenic properties, referred to as gain-of-function (GOF). Reactive oxygen species (ROS) play critical roles as intracellular messengers, regulating numerous signaling pathways linked to metabolism and cell growth. Tumor cells frequently display higher ROS levels compared to healthy cells as a result of their increased metabolism as well as serving as an oncogenic agent because of its damaging and mutational properties. Several studies reported that in contrast with the wild type protein, mutant p53 isoforms fail to exert antioxidant activities and rather increase intracellular ROS, driving a pro-tumorigenic survival. These pro-oxidant oncogenic abilities of GOF mutant p53 include signaling and metabolic rewiring, as well as the modulation of critical ROS-related transcription factors and antioxidant systems, which lead ROS unbalance linked to tumor progression. The studies summarized here highlight that GOF mutant p53 isoforms might constitute major targets for selective therapeutic intervention against several types of tumors and that ROS enhancement driven by mutant p53 might represent an "Achilles heel" of cancer cells, suggesting pro-oxidant drugs as a therapeutic approach for cancer patients bearing the mutant gene.
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http://dx.doi.org/10.3390/biom10030361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175157PMC
February 2020

Mutant p53 induces SIRT3/MnSOD axis to moderate ROS production in melanoma cells.

Arch Biochem Biophys 2020 01 5;679:108219. Epub 2019 Dec 5.

Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Verona, Italy. Electronic address:

The TP53 tumor suppressor gene is the most frequently altered gene in tumors and mutant p53 isoforms can acquire oncogenic properties referred to as gain-of-function (GOF). In this study, we used wild-type (A375) and mutant p53 (MeWo) melanoma cell lines to assess the regulation of the mitochondrial antioxidant manganese superoxide dismutase (MnSOD) by mutant p53. The effects of mutant p53 were evaluated by qPCR, immunoblotting, enzyme activity assay, cell proliferation assay, reactive oxygen species (ROS) assay after cellular transfection. We demonstrate that mutant p53 induces MnSOD expression, which is recovered by the ROS scavenger N-acetyl-l-cysteine. This suggests MnSOD induction as a defense mechanism of melanoma cells to counterbalance the pro-oxidant conditions induced by mutant p53. We also demonstrate that mutant p53 induces the expression of Sirtuin3 (SIRT3), a major mitochondrial NAD-dependent deacetylase, stimulating MnSOD deacetylation and enzymatic activity. Indeed, the restoration of SIRT3 reverses MnSOD activity decrease by mutant p53 knock-down. Finally, MnSOD knock-down further enhances mutant p53-mediated ROS increase, counteracting mutp53-dependent cell hyperproliferation. This indicates that SIRT3 and MnSOD act to maintain ROS levels controlled to promote cell proliferation and survival, providing new therapeutic opportunities to be further considered for clinical studies in cancer patients bearing mutant TP53 gene.
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http://dx.doi.org/10.1016/j.abb.2019.108219DOI Listing
January 2020

Regulation of succinate dehydrogenase and role of succinate in cancer.

Semin Cell Dev Biol 2020 02 1;98:4-14. Epub 2019 May 1.

Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Verona, Italy.

Succinate dehydrogenase (SDH) has been classically considered a mitochondrial enzyme with the unique property to participate in both the citric acid cycle and the electron transport chain. However, in recent years, several studies have highlighted the role of the SDH substrate, i.e. succinate, in biological processes other than metabolism, tumorigenesis being the most remarkable. For this reason, SDH has now been defined a tumor suppressor and succinate an oncometabolite. In this review, we discuss recent findings regarding alterations in SDH activity leading to succinate accumulation, which include SDH mutations, regulation of mRNA expression, post-translational modifications and endogenous SDH inhibitors. Further, we report an extensive examination of the role of succinate in cancer development through the induction of epigenetic and metabolic alterations and the effects on epithelial to mesenchymal transition, cell migration and invasion, and angiogenesis. Finally, we have focused on succinate and SDH as diagnostic markers for cancers having altered SDH expression/activity.
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http://dx.doi.org/10.1016/j.semcdb.2019.04.013DOI Listing
February 2020

Regulation of Autophagy by Nuclear GAPDH and Its Aggregates in Cancer and Neurodegenerative Disorders.

Int J Mol Sci 2019 Apr 26;20(9). Epub 2019 Apr 26.

Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy.

Several studies indicate that the cytosolic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has pleiotropic functions independent of its canonical role in glycolysis. The GAPDH functional diversity is mainly due to post-translational modifications in different amino acid residues or due to protein-protein interactions altering its localization from cytosol to nucleus, mitochondria or extracellular microenvironment. Non-glycolytic functions of GAPDH include the regulation of cell death, autophagy, DNA repair and RNA export, and they are observed in physiological and pathological conditions as cancer and neurodegenerative disorders. In disease, the knowledge of the mechanisms regarding GAPDH-mediated cell death is becoming fundamental for the identification of novel therapies. Here, we elucidate the correlation between autophagy and GAPDH in cancer, describing the molecular mechanisms involved and its impact in cancer development. Since autophagy is a degradative pathway associated with the regulation of cell death, we discuss recent evidence supporting GAPDH as a therapeutic target for autophagy regulation in cancer therapy. Furthermore, we summarize the molecular mechanisms and the cellular effects of GAPDH aggregates, which are correlated with mitochondrial malfunctions and can be considered a potential therapeutic target for various diseases, including cancer and neurodegenerative disorders.
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http://dx.doi.org/10.3390/ijms20092062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6539768PMC
April 2019

Oncometabolites in cancer aggressiveness and tumour repopulation.

Biol Rev Camb Philos Soc 2019 08 10;94(4):1530-1546. Epub 2019 Apr 10.

Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134, Verona, Italy.

Tumour repopulation is recognized as a crucial event in tumour relapse where therapy-sensitive dying cancer cells influence the tumour microenvironment to sustain therapy-resistant cancer cell growth. Recent studies highlight the role of the oncometabolites succinate, fumarate, and 2-hydroxyglutarate in the aggressiveness of cancer cells and in the worsening of the patient's clinical outcome. These oncometabolites can be produced and secreted by cancer and/or surrounding cells, modifying the tumour microenvironment and sustaining an invasive neoplastic phenotype. In this review, we report recent findings concerning the role in cancer development of succinate, fumarate, and 2-hydroxyglutarate and the regulation of their related enzymes succinate dehydrogenase, fumarate hydratase, and isocitrate dehydrogenase. We propose that oncometabolites are crucially involved in tumour repopulation. The study of the mechanisms underlying the relationship between oncometabolites and tumour repopulation is fundamental for identifying efficient anti-cancer therapeutic strategies and novel serum biomarkers in order to overcome cancer relapse.
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http://dx.doi.org/10.1111/brv.12513DOI Listing
August 2019

Mutant p53 blocks SESN1/AMPK/PGC-1α/UCP2 axis increasing mitochondrial O· production in cancer cells.

Br J Cancer 2018 10 15;119(8):994-1008. Epub 2018 Oct 15.

Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Verona, Italy.

Background: The TP53 tumor suppressor gene is the most frequently altered gene in tumors and mutant p53 gain-of-function isoforms actively promote cancer malignancy.

Methods: A panel of wild-type and mutant p53 cancer cell lines of different tissues, including pancreas, breast, skin, and lung were used, as well as chronic lymphocytic leukemia (CLL) patients with different TP53 gene status. The effects of mutant p53 were evaluated by confocal microscopy, reactive oxygen species production assay, immunoblotting, and quantitative reverse transcription polymerase chain reaction after cellular transfection.

Results: We demonstrate that oncogenic mutant p53 isoforms are able to inhibit SESN1 expression and consequently the amount of SESN1/AMPK complex, resulting in the downregulation of the AMPK/PGC-1α/UCP2 axis and mitochondrial O-· production. We also show a correlation between the decrease of reduced thiols with a poorer clinical outcome of CLL patients bearing mutant TP53 gene. The restoration of the mitochondrial uncoupling protein 2 (UCP2) expression, as well as the addition of the radical scavenger N-acetyl-L-cysteine, reversed the oncogenic effects of mutant p53 as cellular hyper-proliferation, antiapoptotic effect, and resistance to drugs.

Conclusions: The inhibition of the SESN1/AMPK/PGC-1α/UCP2 axis contributes to the pro-oxidant and oncogenic effects of mutant p53, suggesting pro-oxidant drugs as a therapeutic approach for cancer patients bearing mutant TP53 gene.
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http://dx.doi.org/10.1038/s41416-018-0288-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203762PMC
October 2018

Mutant p53 prevents GAPDH nuclear translocation in pancreatic cancer cells favoring glycolysis and 2-deoxyglucose sensitivity.

Biochim Biophys Acta Mol Cell Res 2018 12 5;1865(12):1914-1923. Epub 2018 Oct 5.

Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Verona, Italy. Electronic address:

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and devastating human malignancies. In about 70% of PDACs the tumor suppressor gene TP53 is mutated generally resulting in conformational changes of mutant p53 (mutp53) proteins, which acquire oncogenic functions triggering aggressiveness of cancers and alteration of energetic metabolism. Here, we demonstrate that mutant p53 prevents the nuclear translocation of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) stabilizing its cytoplasmic localization, thus supporting glycolysis of cancer cells and inhibiting cell death mechanisms mediated by nuclear GAPDH. We further show that the prevention of nuclear localization of GAPDH is mediated by both stimulation of AKT and repression of AMPK signaling, and is associated with the formation of the SIRT1:GAPDH complex. By using siRNA-GAPDH or an inhibitor of the enzyme, we functionally demonstrate that the maintenance of GAPDH in the cytosol has a critical impact on the anti-apoptotic and anti-autophagic effects driven by mutp53. Furthermore, the blockage of its mutp53-dependent cytoplasmic stabilization is able to restore the sensitivity of PDAC cells to the treatment with gemcitabine. Finally, our data suggest that mutp53-dependent enhanced glycolysis permits cancer cells to acquire sensitivity to anti-glycolytic drugs, such as 2-deoxyglucose, suggesting a potential personalized therapeutic approach in human cancers carrying mutant TP53 gene.
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http://dx.doi.org/10.1016/j.bbamcr.2018.10.005DOI Listing
December 2018

Trichostatin A alters cytoskeleton and energy metabolism of pancreatic adenocarcinoma cells: An in depth proteomic study.

J Cell Biochem 2018 03 21;119(3):2696-2707. Epub 2017 Nov 21.

Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal of all human cancers with a high mortality rate. Resistance to conventional treatments and chemotherapeutics is a typical feature of PDAC. To investigate the causes of drug resistance it is essential to deeply investigate the mechanism of action of chemotherapeutics. In this study, we performed an in depth shotgun proteomic approach using the label-free proteomic SWATH-MS analysis to investigate novel insights of the mechanism of action of the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) in PDAC cells. This proteomic analysis in PaCa44 cells and data elaboration of TSA-regulated proteins by bioinformatics showed an overall up-regulation of cytokeratins and other proteins related to the cytoskeleton organization, keratinization, and apoptotic cell death. On the contrary, a large amount of the down-regulated proteins by TSA treatment belongs to the cellular energetic metabolism and to the machinery of protein synthesis, such as ribosomal proteins, determining synergistic cell growth inhibition by the combined treatment of TSA and the glycolytic inhibitor 2-deoxy-d-glucose in a panel of PDAC cell lines. Data are available via ProteomeXchange with identifier PXD007801.
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http://dx.doi.org/10.1002/jcb.26436DOI Listing
March 2018

UCP2 inhibition induces ROS/Akt/mTOR axis: Role of GAPDH nuclear translocation in genipin/everolimus anticancer synergism.

Free Radic Biol Med 2017 12 27;113:176-189. Epub 2017 Sep 27.

Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy. Electronic address:

Several studies indicate that mitochondrial uncoupling protein 2 (UCP2) plays a pivotal role in cancer development by decreasing reactive oxygen species (ROS) produced by mitochondrial metabolism and by sustaining chemoresistance to a plethora of anticancer drugs. Here, we demonstrate that inhibition of UCP2 triggers Akt/mTOR pathway in a ROS-dependent mechanism in pancreatic adenocarcinoma cells. This event reduces the antiproliferative outcome of UCP2 inhibition by genipin, creating the conditions for the synergistic counteraction of cancer cell growth with the mTOR inhibitor everolimus. Inhibition of pancreatic adenocarcinoma cell growth and induction of apoptosis by genipin and everolimus treatment are functionally related to nuclear translocation of the cytosolic glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The synthetic compound (S)-benzyl-2-amino-2-(S)-3-bromo-4,5-dihydroisoxazol-5-yl-acetate (AXP3009), which binds GAPDH at its redox-sensitive Cys152, restores cell viability affected by the combined treatment with genipin and everolimus, suggesting a role for ROS production in the nuclear translocation of GAPDH. Caspase-mediated apoptosis by genipin and everolimus is further potentiated by the autophagy inhibitor 3-methyladenine revealing a protective role for Beclin1-mediated autophagy induced by the treatment. Mice xenograft of pancreatic adenocarcinoma further confirmed the antiproliferative outcome of drug combination without toxic effects for animals. Tumor masses from mice injected with UCP2 and mTOR inhibitors revealed a strong reduction in tumor volume and number of mitosis associated with a marked GAPDH nuclear positivity. Altogether, these results reveal novel mechanisms through which UCP2 promotes cancer cell proliferation and support the combined inhibition of UCP2 and of Akt/mTOR pathway as a novel therapeutic strategy in the treatment of pancreatic adenocarcinoma.
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http://dx.doi.org/10.1016/j.freeradbiomed.2017.09.022DOI Listing
December 2017

Autocrine mechanisms of cancer chemoresistance.

Semin Cell Dev Biol 2018 06 25;78:3-12. Epub 2017 Jul 25.

Department of Neurosciences, Biomedicine and Movement Sciences, Biochemistry Section, University of Verona, Verona, Italy. Electronic address:

An ever-increasing number of studies highlight the role of cancer secretome in the modification of tumour microenvironment and in the acquisition of cancer cell resistance to therapeutic drugs. The knowledge of the mechanisms underlying the relationship between cancer cell-secreted factors and chemoresistance is becoming fundamental for the identification of novel anticancer therapeutic strategies overcoming drug resistance and novel prognostic secreted biomarkers. In this review, we summarize the novel findings concerning the regulation of secreted molecules by cancer cells compromising drug sensitivity. In particular, we highlight data from available literature describing the involvement of cancer cell-secreted molecules determining chemoresistance in an autocrine manner, including: i) growth factors; ii) glycoproteins; iii) inflammatory cytokines; iv) enzymes and chaperones; and v) tumor-derived exosomes.
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http://dx.doi.org/10.1016/j.semcdb.2017.07.019DOI Listing
June 2018

The antioxidant uncoupling protein 2 stimulates hnRNPA2/B1, GLUT1 and PKM2 expression and sensitizes pancreas cancer cells to glycolysis inhibition.

Free Radic Biol Med 2016 12 27;101:305-316. Epub 2016 Oct 27.

Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy. Electronic address:

Several evidence indicate that metabolic alterations play a pivotal role in cancer development. Here, we report that the mitochondrial uncoupling protein 2 (UCP2) sustains the metabolic shift from mitochondrial oxidative phosphorylation (mtOXPHOS) to glycolysis in pancreas cancer cells. Indeed, we show that UCP2 sensitizes pancreas cancer cells to the treatment with the glycolytic inhibitor 2-deoxy-D-glucose. Through a bidimensional electrophoresis analysis, we identify 19 protein species differentially expressed after treatment with the UCP2 inhibitor genipin and, by bioinformatic analyses, we show that these proteins are mainly involved in metabolic processes. In particular, we demonstrate that the antioxidant UCP2 induces the expression of hnRNPA2/B1, which is involved in the regulation of both GLUT1 and PKM2 mRNAs, and of lactate dehydrogenase (LDH) increasing the secretion of L-lactic acid. We further demonstrate that the radical scavenger N-acetyl-L-cysteine reverts hnRNPA2/B1 and PKM2 inhibition by genipin indicating a role for reactive oxygen species in the metabolic reprogramming of cancer cells mediated by UCP2. We also observe an UCP2-dependent decrease in mtOXPHOS complex I (NADH dehydrogenase), complex IV (cytochrome c oxidase), complex V (ATPase) and in mitochondrial oxygen consumption, suggesting a role for UCP2 in the counteraction of pancreatic cancer cellular respiration. All these results reveal novel mechanisms through which UCP2 promotes cancer cell proliferation with the concomitant metabolic shift from mtOXPHOS to the glycolytic pathway.
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http://dx.doi.org/10.1016/j.freeradbiomed.2016.10.499DOI Listing
December 2016

Molecular interplay between mutant p53 proteins and autophagy in cancer cells.

Biochim Biophys Acta Rev Cancer 2017 Jan 19;1867(1):19-28. Epub 2016 Nov 19.

Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy. Electronic address:

An increasing number of studies highlight the role of mutant p53 proteins in cancer cell growth and in the worsening of cancer patients' clinical outcome. Autophagy has been widely recognized as a main biological event involved in both the regulation of cancer cell proliferation and in the response of several anticancer drugs. A thorough analysis of scientific literature underlines the reciprocal interplay between mutant p53 proteins and autophagy regulation. In this review, we analytically summarize recent findings, which indicate that gain-of-function (GOF) mutant p53 proteins counteract the autophagic machinery by various molecular mechanisms including the regulation of AMPK and Akt/mTOR pathways, autophagy-related genes (ATGs), HIF-1α target genes, and the mitochondrial citrate carrier CIC. Moreover, we report that mutant p53 protein stability is affected by lysosome-mediated degradation through macroautophagy or chaperone-mediated autophagy, suggesting the use of autophagy stimulators to counteract mutant p53 oncogenic activity. Finally, we discuss the functional role of the interplay between mutant p53 proteins and autophagy in cancer progression, a fundamental knowledge to design more effective therapies against cancers bearing mutant TP53 gene.
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http://dx.doi.org/10.1016/j.bbcan.2016.11.003DOI Listing
January 2017

Mutant p53 proteins alter cancer cell secretome and tumour microenvironment: Involvement in cancer invasion and metastasis.

Cancer Lett 2016 07 1;376(2):303-9. Epub 2016 Apr 1.

Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy. Electronic address:

An ever-increasing number of studies highlight the role of mutant p53 proteins in the alteration of cancer cell secretome and in the modification of tumour microenvironment, sustaining an invasive phenotype of cancer cell. The knowledge of the molecular mechanisms underlying the interplay between mutant p53 proteins and the microenvironment is becoming fundamental for the identification of both efficient anticancer therapeutic strategies and novel serum biomarkers. In this review, we summarize the novel findings concerning the regulation of secreted molecules by cancer cells bearing mutant TP53 gene. In particular, we highlight data from available literature, suggesting that mutant p53 proteins are able to (i) alter the secretion of enzymes involved in the modulation of extracellular matrix components; (ii) alter the secretion of inflammatory cytokines; (iii) increase the extracellular acidification; and (iv) regulate the crosstalk between cancer and stromal cells.
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http://dx.doi.org/10.1016/j.canlet.2016.03.046DOI Listing
July 2016

Combining immunofluorescence with in situ proximity ligation assay: a novel imaging approach to monitor protein-protein interactions in relation to subcellular localization.

Histochem Cell Biol 2014 Nov 11;142(5):593-600. Epub 2014 Jul 11.

Histology and Embryology Section, Department of Life and Reproduction Sciences, University of Verona Medical School, Strada le Grazie 8, 37134, Verona, Italy.

The in situ Proximity Ligation Assay (PLA) is suited for visualizing protein-protein interactions and post-translational protein modifications in both tissue sections and in vitro cell cultures. Accurate identification and quantification of protein-protein interactions are critical for in vitro cell analysis, especially when studying the dynamic involvement of proteins in various processes, including cell proliferation, differentiation, and apoptosis. Here, we monitored the interactions between protein kinase-Cζ (PKCζ) and Bcl10 protein in untreated and etoposide (VP-16)-treated C4-I cells by means of a new combined morphological approach and validated it by taking stock of our previous proteomic and biochemical work (Chiarini et al. in J Proteome Res 11:3996-4012, 2012). We first analyzed the colocalization of PKCζ and Bcl10 proteins through classical immunofluorescent colocalization analysis. On the basis of these results, we developed a novel imaging approach combining immunofluorescence (IF) techniques with in situ PLA to identify the PKCζ·Bcl10 complexes at the level of a specific subcellular compartment, i.e., the nuclear envelope (NE). By this means, we could show that the amount of PKCζ·Bcl10 complexes localized at the NE of C4-I cells during proliferation or after treatment with VP-16 closely corresponded to our previous purely biochemical results. Hence, the present findings demonstrate that the combination of in situ PLA with classical IF detection is a novel powerful analytical tool allowing to morphologically demonstrate new specific protein-protein interactions at level of subcellular organelles, the complexes functions of which can next be clarified through proteomic/biochemical approaches.
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http://dx.doi.org/10.1007/s00418-014-1244-8DOI Listing
November 2014

The Aβ peptides-activated calcium-sensing receptor stimulates the production and secretion of vascular endothelial growth factor-A by normoxic adult human cortical astrocytes.

Neuromolecular Med 2014 Dec 20;16(4):645-57. Epub 2014 Jun 20.

Histology and Embryology Section, Department of Life and Reproduction Sciences, University of Verona Medical School, 8 Strada Le Grazie, 37134, Verona, Italy,

The excess vascular endothelial growth factor (VEGF) produced in the Alzheimer's disease (AD) brain can harm neurons, blood vessels, and other components of the neurovascular units (NVUs). But could astrocytes partaking in networks of astrocyte-neuron teams and connected to blood vessels of NVUs contribute to VEGF production? We have shown with cultured cerebral cortical normal (i.e., untransformed) adult human astrocytes (NAHAs) that exogenous amyloid-β peptides (Aβs) stimulate the astrocytes to make and secrete large amounts of Aβs and nitric oxide by a mechanism mediated through the calcium-sensing receptor (CaSR). Here, we report that exogenous Aβs stimulate the NAHAs to produce and secrete even VEGF-A through a CaSR-mediated mechanism. This is indicated by the ability of Aβs to specifically bind the CaSR, and the capability of a CaSR activator, the "calcimimetic" NPS R-568, to imitate, and of the CaSR antagonist, "calcilytic" NPS 2143, to inhibit, the Aβs stimulation of VEGF-A production and secretion by the NAHAs. Thus, Aβs that accumulate in the AD brain may make the astrocytes that envelop and functionally collaborate with neurons into multi-agent AD-driving "machines" via a CaSR signaling mechanism(s). These observations suggest the possibility that CaSR allosteric antagonists such as NPS 2143 might impede AD progression.
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http://dx.doi.org/10.1007/s12017-014-8315-9DOI Listing
December 2014

Do astrocytes collaborate with neurons in spreading the "infectious" aβ and Tau drivers of Alzheimer's disease?

Neuroscientist 2015 Feb 16;21(1):9-29. Epub 2014 Apr 16.

Department of Life & Reproduction Sciences, The University of Verona Medical School, Verona, Italy

Evidence has begun emerging for the "contagious" and destructive Aβ42 (amyloid-beta42) oligomers and phosphorylated Tau oligomers as drivers of sporadic Alzheimer's disease (AD), which advances along a pathway starting from the brainstem or entorhinal cortex and leading to cognition-related upper cerebral cortex regions. Seemingly, Aβ42 oligomers trigger the events generating the neurotoxic Tau oligomers, which may even by themselves spread the characteristic AD neuropathology. It has been assumed that only neurons make and spread these toxic drivers, whereas their associated astrocytes are just janitorial bystanders/scavengers. But this view is likely to radically change since normal human astrocytes freshly isolated from adult cerebral cortex can be induced by exogenous Aβ25-35, an Aβ42 proxy, to make and secrete increased amounts of endogenous Aβ42. Thus, it would seem that the steady slow progression of AD neuropathology along specific cognition-relevant brain networks is driven by both Aβ42 and phosphorylated Tau oligomers that are variously released from increasing numbers of "contagion-stricken" members of tightly coupled neuron-astrocyte teams. Hence, we surmise that stopping the oversecretion and spread of the two kinds of "contagious" oligomers by such team members, perhaps via a specific CaSR (Ca(2+)-sensing receptor) antagonist like NPS 2143, might effectively treat AD.
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http://dx.doi.org/10.1177/1073858414529828DOI Listing
February 2015

Calcium-sensing receptor antagonist (calcilytic) NPS 2143 specifically blocks the increased secretion of endogenous Aβ42 prompted by exogenous fibrillary or soluble Aβ25-35 in human cortical astrocytes and neurons-therapeutic relevance to Alzheimer's disease.

Biochim Biophys Acta 2013 Oct 26;1832(10):1634-52. Epub 2013 Apr 26.

Department of Life and Reproduction Sciences, University of Verona Medical School, Verona, Italy.

The "amyloid-β (Aβ) hypothesis" posits that accumulating Aβ peptides (Aβs) produced by neurons cause Alzheimer's disease (AD). However, the Aβs contribution by the more numerous astrocytes remains undetermined. Previously we showed that fibrillar (f)Aβ25-35, an Aβ42 proxy, evokes a surplus endogenous Aβ42 production/accumulation in cortical adult human astrocytes. Here, by using immunocytochemistry, immunoblotting, enzymatic assays, and highly sensitive sandwich ELISA kits, we investigated the effects of fAβ25-35 and soluble (s)Aβ25-35 on Aβ42 and Aβ40 accumulation/secretion by human cortical astrocytes and HCN-1A neurons and, since the calcium-sensing receptor (CaSR) binds Aβs, their modulation by NPS 2143, a CaSR allosteric antagonist (calcilytic). The fAβ25-35-exposed astrocytes and surviving neurons produced, accumulated, and secreted increased amounts of Aβ42, while Aβ40 also accrued but its secretion was unchanged. Accordingly, secreted Aβ42/Aβ40 ratio values rose for astrocytes and neurons. While slightly enhancing Aβ40 secretion by fAβ25-35-treated astrocytes, NPS 2143 specifically suppressed the fAβ25-35-elicited surges of endogenous Aβ42 secretion by astrocytes and neurons. Therefore, NPS 2143 addition always kept Aβ42/Aβ40 values to baseline or lower levels. Mechanistically, NPS 2143 decreased total CaSR protein complement, transiently raised proteasomal chymotrypsin activity, and blocked excess NO production without affecting the ongoing increases in BACE1/β-secretase and γ-secretase activity in fAβ25-35-treated astrocytes. Compared to fAβ25-35, sAβ25-35 also stimulated Aβ42 secretion by astrocytes and neurons and NPS 2143 specifically and wholly suppressed this effect. Therefore, since NPS 2143 thwarts any Aβ/CaSR-induced surplus secretion of endogenous Aβ42 and hence further vicious cycles of Aβ self-induction/secretion/spreading, calcilytics might effectively prevent/stop the progression to full-blown AD.
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http://dx.doi.org/10.1016/j.bbadis.2013.04.020DOI Listing
October 2013

Alzheimer's disease: an update of the roles of receptors, astrocytes and primary cilia (review).

Int J Mol Med 2013 Jan 24;31(1):3-10. Epub 2012 Oct 24.

Histology and Embryology Section, Department of Life and Reproduction Sciences, University of Verona Medical School, Verona, Venetia, Italy.

The pathophysiological mechanisms underlying the onset and inexorable progression of the late‑onset form of Alzheimer's disease (AD) are still the object of controversy. This review takes stock of some most recent advancements of this field concerning the complex roles played by the amyloid‑β (Aβ)‑binding p75 neurotrophin receptor (p75NTR) and calcium‑sensing receptor (CaSR) and by the primary cilia in AD. Apart from their physiological roles, p75NTR is more intensely expressed in the hippocampus of human AD brains and Aβ‑bound p75NTR triggers cell death, whereas Aβ‑bound CaSR signalling induces the de novo synthesis and release of nitric oxide (NO), vascular endothelial growth factor (VEGF)‑A and Aβ peptides (Aβs), particularly on the part of normal adult human astrocytes. The latter effect could significantly increase the pool of Aβ‑ and NO‑producing nerve cells favouring the progressive spread of a self‑sustaining and self‑reinforcing 'infectious' mechanism of neural and vascular (i.e. blood-brain barrier) cell damage. Interestingly, primary cilia concentrate p75NTR receptors in their membranes and are abnormally structured/damaged in transgenic (Tg) AD‑model mice, which could impact on the adult neurogenesis occurring in the dentate gyrus's subgranular zone (SGZ) that is necessary for new memory encoding, thereby favouring typical AD cognitive decline. Altogether, these findings may pave the way to novel therapeutic approaches to AD, particularly in its mild cognitive impairment (MCI) and pre‑MCI stages of development.
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http://dx.doi.org/10.3892/ijmm.2012.1162DOI Listing
January 2013

The calcium-sensing receptor: a novel Alzheimer's disease crucial target?

J Neurol Sci 2012 Nov 28;322(1-2):137-40. Epub 2012 Jul 28.

Histology and Embryology Unit, Department of Life and Reproduction Sciences, University of Verona Medical School, Verona, Venetia, Italy.

Alzheimer's disease (AD) is the most common human neurodegenerative ailment, the most prevalent (>95%) late-onset type of which has a still uncertain etiology. The progressive decline of cognitive functions, dementia, and physical disabilities of AD is caused by synaptic losses that progressively disconnect key neuronal networks in crucial brain areas, like the hippocampus and temporoparietal cortex, and critically impair language, sensory processing, memory, and conscious thought. AD's two main hallmarks are fibrillar amyloid-β (fAβ) plaques in extracellular spaces and intracellular accumulation of fAβ peptides and neurofibrillary tangles (NFTs). It is still undecided whether either or both these AD hallmarks cause or result from the disease. Recently, the dysregulation of calcium homeostasis has been advanced as a novel cause of AD. In this case, a suitable candidate of AD driver would be the Aβ peptides-binding/activated calcium-sensing receptor (CaSR), whose intracellular signalling is triggered by Aβ peptides. In this review, we briefly discuss CaSR's roles in normal adult human astrocytes (NAHAs) and their possible impacts on AD.
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http://dx.doi.org/10.1016/j.jns.2012.07.031DOI Listing
November 2012

Role-shifting PKCζ fosters its own proapoptotic destruction by complexing with Bcl10 at the nuclear envelope of human cervical carcinoma cells: a proteomic and biochemical study.

J Proteome Res 2012 Aug 19;11(8):3996-4012. Epub 2012 Jul 19.

Histology & Embryology Unit, Department of Life & Reproduction Sciences, University of Verona Medical School, Verona, I-37134, Italy.

Many features of deadly human cervical cancers (HCCs) still require elucidation. Among HCC-derived cell lines, here we used the C4-I one since its quantitative gene expression pattern most closely mimics invasive HCCs, including protein kinase-Cζ (PKCζ) overexpression. Via proteomic, bioinformatic, and biochemical approaches we identified 31 and 33 proteins co-immunoprecipitating with PKCζ from nuclear membranes (NMs) of, respectively, untreated or VP-16-exposed C4-I cells. Such proteins belonged to eight functional groups, whose compositions and relative sizes changed with either context. Of the 56 proteins identified, only eight were shared between the two subproteomes, including Bcl10. Surprisingly, proteins known to associate with Bcl10, like Carma1/3 and Malt1, in so-called CBM signalosomes were absent. Notably, in VP-16-treated C4-I cells, PKCζ•Bcl10 complexes increasingly accrued at NMs, where PKCζ phosphorylated Bcl10, as PKCζ also did in vitro and in cell-free systems, both processes being thwarted by interfering RNA (iRNA) PKCζ depletion. Caspase-3 was associated with PKCζ•Bcl10 complexes and proteolyzed PKCζ leading to its inactivation/destruction; both events were prevented by Bcl10 iRNA suppression. Thus, PKCζ's molecular interactions and functional roles changed strikingly according to the untreated or apoptogen-treated cells context, and by complexing with Bcl10, PKCζ surprisingly favored its own demise, which suggests both proteins as HCCs therapeutic targets.
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http://dx.doi.org/10.1021/pr3000464DOI Listing
August 2012

The amyloid-β₄₂ proxy, amyloid-β(25-35), induces normal human cerebral astrocytes to produce amyloid-β₄₂.

J Alzheimers Dis 2011 ;24(2):335-47

Histology and Embryology Section, Department of Life and Reproduction Sciences, University of Verona Medical School, Verona, Italy.

Astrocytes in amyloid-β (Aβ)₄₂-accumulating human brains afflicted with Alzheimer's disease (AD) upregulate vascular endothelial growth factor (VEGF)-A synthesis and also become loaded with Aβ₄₂. We have already shown that Aβ(25-35) (surrogate of Aβ₄₂)-induced VEGF-A production in 'normoxic' cultures of early passage normal human cerebral astrocytes (NAHAs) is mediated by the stabilization of VEGF gene-stimulating hypoxia-inducible factor (HIF)-1α and nuclear translocation of HIF-1α•HIF-1β complexes. We have now found that treating these NAHAs with Aβ(25-35) also stimulates them to make Aβ₄₂ (appearing in immunoblots as several bands with M(r)'s from 8 kDa upwards), whose levels peak at 48 h (2.8-fold versus 0 h, p < 0.001) and then start falling slowly. This rise of Aβ₄₂ peptide production coincides with a transiently increased flow of HIF-1α (therefore HIF-1α•HIF-1β complexes; at 24 h, 1.5-fold versus 0 h, p < 0.001) into the nucleus and transient surges first of β-secretase (BACE-1/β-S) mRNA expression (1.2-fold versus 0 h, p = 0.013) and activity peaking at 24-h (1.4-fold versus 0 h, p = 0.001), and then of γ-secretase (γ-S) activity cresting at 48 h (1.6-fold versus 0 h, p < 0.001) that cleave the Aβ₄₂ peptides from amyloid-β protein precursor. Since the genes encoding components of these two secretases have the same HIF-1α•HIF-1β-responsive elements in their promoters as the VEGF gene, these observations suggest that the Aβ₄₂ released from neurons in the AD brain can recruit associated astrocytes via HIF-1α•HIF-1β signaling into the pool of Aβ₄₂-producing cells. In other words, Aβ₄₂ begets Aβ₄₂ in NAHAs.
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http://dx.doi.org/10.3233/JAD-2011-101626DOI Listing
August 2011

Calphostin C, a remarkable multimodal photodynamic killer of neoplastic cells by selective nuclear lamin B1 destruction and apoptogenesis (Review).

Oncol Rep 2010 Apr;23(4):887-92

Department of Biomedical and Surgical Sciences, University of Verona Medical School, I-37134 Verona, Italy.

Perylenequinones that generate reactive oxygen species (ROS) when illuminated with visible light have been recommended as photodynamic chemotherapeutic agents. One of these is calphostin C (CalC), the action of the photo-activated derivative of which, CalCphiE, has been ascribed to its ability to selectively and irreversibly inhibit protein kinase Cs (PKCs). But recent results of experiments with neoplastic rat fibroblasts and human breast and uterine cervix cancer cells have revealed that the action of CalCphiE involves more than PKC inhibition. Besides suppressing PKC activity, CalCphiE rapidly causes endoplasmic reticulum (ER) stress in breast cancer cells and the selective complete oxidation and proteasomal destruction of the functionally essential nuclear envelope protein lamin B1, in human cervical carcinoma (HCC) cells and neoplastic rat fibroblasts. When these lamin B1-lacking cells are placed in the dark, cytoplasmic membrane-linked PKC activities suddenly rebound and apoptogenesis is initiated as indicated by the immediate release of cytochrome c from mitochondria and later on the activation of caspases. Hence, CalCphiE is a photodynamic cytocidal agent attacking multiple targets in cancer cells and it would be worth determining, even for their best applicative use, whether other perylenequinones also share the so far unexpectedly complex deadly properties of the CalCphiE.
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http://dx.doi.org/10.3892/or_00000711DOI Listing
April 2010

Proteomic analysis of GTP cyclohydrolase 1 multiprotein complexes in cultured normal adult human astrocytes under both basal and cytokine-activated conditions.

Proteomics 2009 Apr;9(7):1850-60

Department of Biomedical and Surgical Sciences, Histology and Embryology Unit, University of Verona Medical School, Verona, Italy.

GTP cyclohydrolase 1 (GCH1) is the rate-limiting enzyme of a metabolic pathway synthesizing tetrahydrobiopterin (BH(4)), the cofactor dimerizing and activating inducible nitric oxide synthase (NOS-2). GCH1 protein expression and enzyme activity are minimal in cultured, phenotypically stable, untreated normal adult human astrocytes (NAHA), but are strongly induced, together with NOS-2, by a mixture of three proinflammatory cytokines (IL-1beta, TNF-alpha, and IFN-gamma--the CM-trio) released by microglia under brain-damaging conditions. The resulting hyper-production of NO severely harms neurons. In this study, using MALDI-TOF/MS, PMF, Western immunoblotting (WB), and antibody microarrays we identified several proteins coimmunoprecipitating with GCH1. Under basal conditions, GCH1 was associated with various adaptor/regulator molecules involved in G-protein-coupled receptors signalling, protein serine/threonine phosphatase 2Cbeta (PP2Cbeta), and serine-threonine kinases like Ca(2+) calmodulin kinases (CaMKs), casein kinases (CKs), cAMP-dependent kinases (PKAs), and mitogen-activated protein kinases (MAPKs). Exposure to the three cytokines' mixture (CM-trio) significantly changed, within the 48-72 h required for the induction and activation of GCH1, the levels and identities of some of the 0 h-associated proteins: after 72 h CK-IIalpha tended to dissociate from, whereas MAPK12 and JNK3 were strongly associated with fully active GCH1. These findings provide a first enticing glimpse into the intricate mechanisms regulating GCH1 activation by proinflammatory cytokines in NAHA, and may have therapeutic implications.
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http://dx.doi.org/10.1002/pmic.200800561DOI Listing
April 2009

Photoexcited calphostin C selectively destroys nuclear lamin B1 in neoplastic human and rat cells - a novel mechanism of action of a photodynamic tumor therapy agent.

Biochim Biophys Acta 2008 Sep 6;1783(9):1642-53. Epub 2008 Apr 6.

Histology and Embryology Unit, Department of Biomedical and Surgical Sciences, University of Verona Medical School, Verona, I-37134, Italy.

Lamin B1, a major component of the nuclear lamina, anchors the nucleus to the cytoskeletal cage, and controls nuclear orientation, chromosome positioning and, alongside several enzymes, fundamental nuclear functions. Exposing polyomavirus-transformed rat pyF111 fibroblasts and human cervical carcinoma (HCC) C4-I cells for 30 min to photoexcited perylenequinone calphostin C, i.e. Cal C(phiE), an established reactive oxygen species (ROS)-generator and protein kinase C (PKC) inhibitor, caused the cells to selectively oxidize and then totally destroy their nuclear lamin B1 by only 60 min after starting the treatment, i.e. when apoptotic caspases' activities had not yet increased. However, while the oxidized lamin B1 was being destroyed, lamins A/C, the lamin A-associated nuclear envelope protein emerin, and the nucleoplasmic protein cyclin E were neither oxidized nor destroyed. The oxidized lamin B was ubiquitinated and demolished in the proteasome probably by an enhanced peptidyl-glutaminase-like activity. Hence, the Cal C(phiE)-induced rapid and selective lamin B1 oxidation and proteasomal destruction ahead of the activation of apoptotic caspases was by itself a most severe molecular lesion impairing vital nuclear functions. Conversely, Cal C directly added to the cells kept in the dark damaged neither nuclear lamin B1 nor cell viability. Thus, our findings reveal a novel cell-damaging mechanism of a photodynamic tumor therapeutic agent.
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http://dx.doi.org/10.1016/j.bbamcr.2008.03.014DOI Listing
September 2008

Emerging concepts of how β-amyloid proteins and pro-inflammatory cytokines might collaborate to produce an 'Alzheimer brain' (Review).

Mol Med Rep 2008 Mar-Apr;1(2):173-8

Histology and Embryology Unit, Department of Biomedical and Surgical Sciences, University of Verona Medical School, I-37134 Verona, Italy.

Three steps lead to the development of full-blown sporadic or late-onset Alzheimer's disease or dementia (AD). In the young brain, amyloid β-(1-42) (Aβ 42) is a normal aggregation-prone protein product of neuronal activity that is kept at a safe low level by proteolysis in neurons and glial cells, and by expulsion across the blood-brain barrier. But clearance declines with advancing age. Step 1: Because of the normal decline with age of the Aβ 42-clearing mechanisms, toxic amyloid-derived diffusible ligands (ADDLs) made of dodecamers of the aggregation-prone Aβ 42 start accumulating. These Aβ 42 dodecamers selectively target the initially huge numbers of excitatory synapses of neurons and cause them to start slowly dropping, which increasingly impairs plasticity and sooner or later starts noticeably affecting memory formation. At a certain point, this increasing loss of synapses induces the neurons to redirect their still-expressed cell cycle proteins from post-mitotic jobs, such as maintaining synapses, to starting a cell cycle and partially or completely replicating DNA without entering mitosis. The resulting aneuploid or tetraploid neurons survive for as long as 6-12 months as quasi-functional 'undead zombies', with developing tangles of hyperphosphorylated τ protein disrupting the vital anterograde axonal transport of mitochondria and other synapse-vital components. Step 2: The hallmark AD plaques appear as Aβ 42 clearance continues to decline and the formation of Aβ 42 non-diffusible fibrils begins in the aging brain. Step 3: A terminal cytokine-driven maëlstrom begins in the aging brain when microglia, the brain's professional macrophages, are activated in and around the plaques. They produce pro-inflammatory cytokines, such as IFN-γ, IL-1β and TNF-α. One of these, IFN-γ, causes the astrocytes enwrapping the neuronal synapses to express their β-secretase (BACE1) genes and produce and release Aβ 42, which can kill the closely apposed neurons by binding to their p75NTR receptors, which generate apoptogenic signals. Astrocytes are also stimulated by the same cytokines to turn on their nitric oxide synthase (NOS)-2 genes and start pouring large amounts of nitric oxide (NO) and its cytocidal derivative peroxynitrite (ONOO-) directly out onto the closely apposed neurons.
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October 2012

Comano's (Trentino) thermal water interferes with tumour necrosis factor-alpha expression and interleukin-8 production and secretion by cultured human psoriatic keratinocytes: yet other mechanisms of its anti-psoriatic action.

Int J Mol Med 2007 Mar;19(3):373-9

Histology and Embryology Unit, Department of Biomedical and Surgical Sciences, University of Verona Medical School, Verona I-37134, Italy.

Thermal balneotherapy with Comano's spa water (CW; Trentino, Italy) is beneficial for psoriasis and other skin disorders but its operative mechanisms are largely unknown. Previously, we showed that CW interferes with the production and secretion of IL-6 and various VEGF-A isoforms and with CK-16 expression by cultured human psoriatic keratinocytes. In this study, confluent cultures of epidermal keratinocytes isolated from the lesional areas of 9 psoriatic patients were exposed for 11-13 days to DMEM, whose chemicals had been dissolved in either deionised water (DW-DMEM, controls) or CW (CW-DMEM, treated cells), in order to assess the expression and secretion of TNF-alpha and IL-8 by such cells. The results gained by means of immunocytochemistry, Western immunoblotting (WB), and ELISA assays showed that CW exposure significantly down-regulated the intracellular levels of TNF-alpha, a key inducer of IL-8, IL-6, and other chemokines. However, no assayable TNF-alpha secretion occurred in keratinocyte-conditioned DW- and CW-DMEM samples. Moreover, the intracellular levels and secretion rates of IL-8 were also markedly reduced in the protein extracts and conditioned media of CW-DMEM-incubated keratinocytes. Notably, the most effective inhibition of IL-8 secretion was elicited by a 25% CW fraction in the DMEM. Altogether, our findings indicate that by attenuating at lesional skin sites the deregulated production and secretion of a cascade of several cytokines and chemokines (e.g. TNF- alpha, IL-8, IL-6, and various VEGF-A isoforms), and by offsetting the keratinocytes' abnormal differentiation program entailing CK-16 expression, CW balneotherapy may beneficially influence the clinical manifestations of psoriasis.
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March 2007

Comano's (Trentino) thermal water interferes with interleukin-6 production and secretion and with cytokeratin-16 expression by cultured human psoriatic keratinocytes: further potential mechanisms of its anti-psoriatic action.

Int J Mol Med 2006 Dec;18(6):1073-9

Histology and Embryology Unit, Department of Biomedical and Surgical Sciences, University of Verona Medical School, Verona I-37134, Italy.

Thermal balneotherapy with Comano's spa water (CW; Trentino, Italy) is used for psoriasis and other skin disorders but its mechanisms of action are mostly unknown. Previously, we showed that CW can interfere with the expression and secretion of various VEGF-A isoforms by cultured human psoriatic epidermal keratinocytes. In this study, confluent cultures of IL-6-hypersecreting keratino-cytes isolated from 6 psoriatic patients were exposed for 11-15 days to DMEM, the chemicals of which had been dissolved in either deionised water (DW-DMEM, controls) or CW (CW-DMEM, treated cells). As detected by means of immunocytochemistry, Western immunoblotting, and ELISA assays, the intracellular levels and secretion rates of IL-6 were drastically curtailed in the CW-DMEM-incubated keratinocytes and in their cell-conditioned media. A nearly maximal inhibition of IL-6 release had already been induced by a CW fraction in the DMEM as low as 25%. CW exposure also promptly, intensely, and persistently down-regulated the expression of cytokeratin-16 (CK-16), a marker associated with keratinocyte psoriatic phenotype. Hence, CW balneotherapy may beneficially affect the clinical manifestations of psoriasis via an attenuation of the local deregulation of several cytokines/chemokines, including IL-6 and VEGF-A isoforms, and of a concurrent, abnormal cell differentiation program entailing the expression, amongst other proteins, of CK-16.
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December 2006

Comano's (Trentino) thermal water interferes with the expression and secretion of vascular endothelial growth factor-A protein isoforms by cultured human psoriatic keratinocytes: a potential mechanism of its anti-psoriatic action.

Int J Mol Med 2006 Jul;18(1):17-25

Histology and Embryology Unit, Department of Biomedical and Surgical Sciences, University of Verona Medical School, I-37134 Verona, Italy.

Thermal balneotherapy with Comano spa's water (CW; Trentino, Italy) is used for psoriasis and other skin disorders but the mechanism(s) of action of this hypotonic water are unknown. Since skin psoriatic manifestations are thought to be angiogenesis-dependent, we assessed CW's effects on the expression and release of VEGF-A protein isoforms by cultured human lesional keratinocytes isolated from skin biopsies performed in 9 patients. Confluent, psoriatic keratinocytes were exposed for 11 days to DMEM, whose chemicals had been dissolved in either deionised water (DW-DMEM, controls) or CW (CW-DMEM, treated cells). As detected by Western immunoblotting (WB), incubation in CW-DMEM elicited, with respect to DW-DMEM, an increase in intracellular and/or cell-bound L-VEGF-A189 and L-VEGF-A165 48 kDa protein isoforms with no concurrent change in L-VEGF-A121 and L-VEGF-A165 45 kDa proteins. Moreover, WB analysis of the secreted VEGF-A (sVEGF-A) proteins showed that the 20 and 15 kDa bands corresponding to different VEGF-A isoforms were directly and remarkably reduced in keratinocyte-conditioned CW-DMEM vs. DW-DMEM. Thus, CW interferes with VEGF-A isoform expression and secretion by the psoriatic keratinocytes. These effects would reduce all VEGF-A-mediated angiogenic, vessel permeabilising, and chemotactic effects, thereby at least in part explaining the beneficial actions of CW balneotherapy on the clinical manifestations of psoriasis.
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July 2006

Soluble amyloid beta-peptide and myelin basic protein strongly stimulate, alone and in synergism with combined proinflammatory cytokines, the expression of functional nitric oxide synthase-2 in normal adult human astrocytes.

Int J Mol Med 2005 Nov;16(5):801-7

Histology and Embryology Unit, Department of Biomedical and Surgical Sciences, University of Verona Medical School, Verona, I-37134, Italy.

The accumulation of amyloid beta (Abeta)-peptides and their collection in fibrillar plaques in the human brain are believed to be responsible for Alzheimer's disease. The major neuron killers in the Alzheimer brain include proinflammatory cytokines and NO made by NOS-2 (inducible nitric oxide synthase-2). We have determined the effect of a soluble Abeta peptide, Abeta(1-40), on the expression of NOS-2 in astrocytes using a novel model system consisting of pure cultures of cells from adult human brains that, after the first three passages in vitro, become stably locked into the normal astrocytic phenotype like their counterparts in the adult human brain. Abeta(1-40) alone stimulated quiescent astrocytes to start expressing functional NOS-2 and dumping NO into the culture medium during the next 4 days. But adding three of the proinflammatory cytokines commonly produced in the Alzheimer brain--IFN-gamma, IL-1beta, and TNF-alpha--along with Abeta(1-40) more than trebled NOS-2 expression and doubled NO production. In view of the possibility of myelin breakdown in the Alzheimer brain, we also tested the capability of myelin basic protein (MBP) to stimulate NO production using human astrocytes. We found that MBP mimicked the ability of Abeta(1-40) to induce cells to release NO and adding the cytokine triad along with MBP more than doubled NO production and release. Thus, it appears that Abeta peptides and MBP can join forces with proinflammatory cytokines to enhance the NO-mediated killing of neurons in the Alzheimer brain.
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November 2005