Publications by authors named "Cinzia Domenicotti"

50 Publications

D-α-Tocopherol-Based Micelles for Successful Encapsulation of Retinoic Acid.

Pharmaceuticals (Basel) 2021 Mar 4;14(3). Epub 2021 Mar 4.

Department of Pharmacy (DiFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy.

All--retinoic acid (ATRA) represents the first-choice treatment for several skin diseases, including epithelial skin cancer and acne. However, ATRA's cutaneous side effects, like redness and peeling, and its high instability limit its efficacy. To address these drawbacks and to improve ATRA solubilization, we prepared ATRA-loaded micelles (ATRA-TPGSs), by its encapsulation in D-α-tocopheryl-polyethylene-glycol-succinate (TPGS). First, to explore the feasibility of the project, a solubility study based on the equilibrium method was performed; then, six ATRA-TPGS formulations were prepared by the solvent-casting method using different TPGS amounts. ATRA-TPGSs showed small sizes (11-20 nm), low polydispersity, slightly negative zeta potential, and proved good encapsulation efficiency, confirmed by a chemometric-assisted Fourier transform infrared spectroscopy (FTIR) investigation. ATRA-TPGS stability was also investigated to choose the most stable formulation. Using Carbopol 980 as gelling agent, ATRA-TPGS-loaded gels were obtained and analyzed for their rheological profiles. Ex vivo release studies from ATRA-TPGSs were performed by Franz cells, demonstrating a permeation after 24 h of 22 ± 4 µ cm. ATRA-TPGSs showed enhanced cytotoxic effects on melanoma cells, suggesting that these formulations may represent a valid alternative to improve patient compliance and to achieve more efficacious therapeutic outcomes.
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http://dx.doi.org/10.3390/ph14030212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7999664PMC
March 2021

Potential Role of miRNAs in the Acquisition of Chemoresistance in Neuroblastoma.

J Pers Med 2021 Feb 7;11(2). Epub 2021 Feb 7.

Department of Experimental Medicine, University of Genova, 16100 Genova, Italy.

Neuroblastoma (NB) accounts for about 8-10% of pediatric cancers, and the main causes of death are the presence of metastases and the acquisition of chemoresistance. Metastatic NB is characterized by amplification that correlates with changes in the expression of miRNAs, which are small non-coding RNA sequences, playing a crucial role in NB development and chemoresistance. In the present study, miRNA expression was analyzed in two human -amplified NB cell lines, one sensitive (HTLA-230) and one resistant to Etoposide (ER-HTLA), by microarray and RT-qPCR techniques. These analyses showed that miRNA-15a, -16-1, -19b, -218, and -338 were down-regulated in ER-HTLA cells. In order to validate the presence of this down-regulation in vivo, the expression of these miRNAs was analyzed in primary tumors, metastases, and bone marrow of therapy responder and non-responder pediatric patients. Principal component analysis data showed that the expression of miRNA-19b, -218, and -338 influenced metastases, and that the expression levels of all miRNAs analyzed were higher in therapy responders in respect to non-responders. Collectively, these findings suggest that these miRNAs might be involved in the regulation of the drug response, and could be employed for therapeutic purposes.
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http://dx.doi.org/10.3390/jpm11020107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7916079PMC
February 2021

Biological evaluation of pyrazolyl-urea and dihydro-imidazo-pyrazolyl-urea derivatives as potential anti-angiogenetic agents in the treatment of neuroblastoma.

Oncotarget 2020 Sep 15;11(37):3459-3472. Epub 2020 Sep 15.

Department of Experimental Medicine, General Pathology Section, University of Genoa, Genoa, Italy.

Pyrazolyl-urea and dihydro-imidazo-pyrazolyl-urea compounds (STIRUR 13, STIRUR 41 and BUR 12) have been demonstrated to exert a strong inhibitory effect on interleukin 8 or N-formyl-methionyl-leucyl-phenylalanine-induced chemotaxis of human neutrophils. Since the migration of cancer cells is comparable to that of neutrophils, the purpose of this study is to evaluate the biological effect of STIRUR 13, STIRUR 41 and BUR 12 on ACN and HTLA-230, two neuroblastoma (NB) cell lines with different degree of malignancy. HTLA-230 cells, stage-IV NB cells, have high plasticity and can serve as progenitors of endothelial cells. The results herein reported show that the three tested compounds were not cytotoxic for both NB cells and did not alter their clonogenic potential. However, all compounds were able to inhibit the ability of HTLA-230 to form vascular-like structures. On the basis of these findings, pyrazolyl-urea and dihydro-imidazo-pyrazolyl-urea derivatives could be proposed as agents potentially effective in counteracting NB malignancy by inhibiting cell migration and tumor angiogenesis which represent important hallmarks responsible for cancer survival and progression.
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http://dx.doi.org/10.18632/oncotarget.27733DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7500105PMC
September 2020

Dendrimer Nanodevices and Gallic Acid as Novel Strategies to Fight Chemoresistance in Neuroblastoma Cells.

Nanomaterials (Basel) 2020 Jun 26;10(6). Epub 2020 Jun 26.

Department of Experimental Medicine-DIMES, University of Genoa, Via Alberti L.B., 16132 Genoa, Italy.

Human neuroblastoma (NB), a pediatric tumor inclined to relapse, after an initial response to therapy, usually develops resistance. Since several chemotherapeutics exert anticancer effect by increasing reactive oxygen species (ROS), NB cells overproduce antioxidant compounds becoming drugs-resistant. A strategy to sensitize NB cells to chemotherapy involves reducing their antioxidant defenses and inducing ROS overproduction. Concerning this, although affected by several issues that limit their clinical application, antioxidant/pro-oxidant polyphenols, such as gallic acid (GA), showed pro-oxidant anti-cancer effects and low toxicity for healthy cells, in several kind of tumors, not including NB. Herein, for the first time, free GA, two GA-dendrimers, and the dendrimer adopted as GA reservoir were tested on both sensitive and chemoresistant NB cells. The dendrimer device, administered at the dose previously found active versus sensitive NB cells, induced ROS-mediated death also in chemoresistant cells. Free GA proved a dose-dependent ROS-mediated cytotoxicity on both cell populations. Intriguingly, when administered in dendrimer formulations at a dose not cytotoxic for NB cells, GA nullified any pro-oxidant activity of dendrimer. Unfortunately, due to GA, nanoformulations were inactive on NB cells, but GA resized in nanoparticles showed considerable ability in counteracting, at low dose, ROS production and oxidative stress, herein induced by the dendrimer.
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http://dx.doi.org/10.3390/nano10061243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353457PMC
June 2020

Anticancer effect of physical activity is mediated by modulation of extracellular microRNA in blood.

Oncotarget 2020 Jun 2;11(22):2106-2119. Epub 2020 Jun 2.

Department of Experimental Medicine, University of Genoa, Genoa, Italy.

Epidemiological studies provide evidence that physical activity reduces the risk of cancer, particularly of breast cancer. However, little is known about the underlying molecular mechanisms as related to microRNAs. The goal of the herein presented study is to explore the involvement of miRNAs in beneficial effects exerted by physical activity in breast cancer prevention. Thirty subjects (mean age: 57.1 ± 14.7 years) underwent 45 minutes of treadmill walking under standardized conditions. The levels of extracellular miRNAs were evaluated in blood plasma before and after structured exercise by means of microarray analysis of 1,900 miRNAs identifying mostly modulated miRNAs. Structured exercise has been found to modulate the expression of 14 miRNAs involved in pathways relevant to cancer. The different expression of two miRNAs involved in breast cancer progression, i. e. up-regulation of miR-206 and down-regulation of anti-miR-30c, were the most striking effects induced by exercise. The biological effects of these miRNAs were investigated in MCF-7 human breast cancer cells. miR-206 transfection and anti-miR-30c silencing, inhibited cell growth and increased apoptosis of MCF-7 cells. Moreover, the combined use of the two miRNAs further enhanced apoptosis and induced growth arrest in the G1/S phase of cell cycle. Our results support that physical activity effectively change the expression of extracellular miRNAs. Specifically, miR-206 up-regulation and anti-miR-30c down-regulation act as suppressors in breast cancer cells. The evaluation of these miRNAs in blood can be used as non-invasive biomarkers for breast cancer prevention.
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http://dx.doi.org/10.18632/oncotarget.27609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7275780PMC
June 2020

Polyester-Based Dendrimer Nanoparticles Combined with Etoposide Have an Improved Cytotoxic and Pro-Oxidant Effect on Human Neuroblastoma Cells.

Antioxidants (Basel) 2020 Jan 6;9(1). Epub 2020 Jan 6.

Department of Experimental Medicine (DIMES), University of Genova, Via Alberti L.B., 16132 Genoa, Italy.

Etoposide (ETO) is a cytotoxic drug that exerts its effect by increasing reactive oxygen species (ROS) production. Although ETO is widely used, fast metabolism, poor solubility, systemic toxicity, and multi-drug resistance induction all limit its administration dosage and its therapeutic efficiency. In order to address these issues, a biodegradable dendrimer was prepared for entrapping and protecting ETO and for enhancing its solubility and effectiveness. The achieved dendrimer complex with ETO (CPX ) showed the typical properties of a well-functioning delivery system, i.e., nanospherical morphology (70 nm), optimal Z-potential (-45 mV), good drug loading (37%), very satisfying entrapment efficiency (53%), and a remarkably improved solubility in biocompatible solvents. In regards to its cytotoxic activity, CPX was tested on neuroblastoma (NB) cells with very promising results. In fact, the dendrimer scaffold and ETO are able to exert per se a cytotoxic and pro-oxidant activity on human NB cells. When CPX is combined with ETO, it shows a synergistic action, slowly releasing the drug over time and significantly improving and protracting bioactivity. On the basis of these findings, the prepared ETO reservoir represents a novel biodegradable and promising device for the delivery of ETO into NB cells.
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http://dx.doi.org/10.3390/antiox9010050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022520PMC
January 2020

miRNA Regulation of Glutathione Homeostasis in Cancer Initiation, Progression and Therapy Resistance.

Microrna 2020 ;9(3):187-197

Department of Experimental Medicine, University of Genoa, Genoa, Italy.

Glutathione (GSH) is the most abundant antioxidant that contributes to regulating the cellular production of Reactive Oxygen Species (ROS) which, maintained at physiological levels, can exert a function of second messengers in living organisms. In fact, it has been demonstrated that moderate amounts of ROS can activate the signaling pathways involved in cell growth and proliferation, while high levels of ROS induce DNA damage leading to cancer development. Therefore, GSH is a crucial player in the maintenance of redox homeostasis and its metabolism has a role in tumor initiation, progression, and therapy resistance. Our recent studies demonstrated that neuroblastoma cells resistant to etoposide, a common chemotherapeutic drug, show a partial monoallelic deletion of the locus coding for miRNA 15a and 16-1 leading to a loss of these miRNAs and the activation of GSH-dependent responses. Therefore, the aim of this review is to highlight the role of specific miRNAs in the modulation of intracellular GSH levels in order to take into consideration the use of modulators of miRNA expression as a useful strategy to better sensitize tumors to current therapies.
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http://dx.doi.org/10.2174/2211536609666191218103220DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7366003PMC
January 2020

MYC Expression and Metabolic Redox Changes in Cancer Cells: A Synergy Able to Induce Chemoresistance.

Oxid Med Cell Longev 2019 25;2019:7346492. Epub 2019 Jun 25.

Department of Experimental Medicine, General Pathology Section, University of Genova, Italy.

Chemoresistance is due to multiple factors including the induction of a metabolic adaptation of tumor cells. In fact, in these cells, stress conditions induced by therapies stimulate a metabolic reprogramming which involves the strengthening of various pathways such as glycolysis, glutaminolysis and the pentose phosphate pathway. This metabolic reprogramming is the result of a complex network of mechanisms that, through the activation of oncogenes (i.e., MYC, HIF1, and PI3K) or the downregulation of tumor suppressors (i.e., TP53), induces an increased expression of glucose and/or glutamine transporters and of glycolytic enzymes. Therefore, in order to overcome chemoresistance, it is necessary to develop combined therapies which are able to selectively and simultaneously act on the multiple molecular targets responsible for this adaptation. This review is focused on highlighting the role of MYC in modulating the epigenetic redox changes which are crucial in the acquisition of therapy resistance.
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http://dx.doi.org/10.1155/2019/7346492DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614970PMC
February 2020

Etoposide-resistance in a neuroblastoma model cell line is associated with 13q14.3 mono-allelic deletion and miRNA-15a/16-1 down-regulation.

Sci Rep 2018 09 13;8(1):13762. Epub 2018 Sep 13.

Department of Experimental Medicine, General Pathology Section, University of Genova, Genova, Italy.

Drug resistance is the major obstacle in successfully treating high-risk neuroblastoma. The aim of this study was to investigate the basis of etoposide-resistance in neuroblastoma. To this end, a MYCN-amplified neuroblastoma cell line (HTLA-230) was treated with increasing etoposide concentrations and an etoposide-resistant cell line (HTLA-ER) was obtained. HTLA-ER cells, following etoposide exposure, evaded apoptosis by altering Bax/Bcl2 ratio. While both cell populations shared a homozygous TP53 mutation encoding a partially-functioning protein, a mono-allelic deletion of 13q14.3 locus, where the P53 inducible miRNAs 15a/16-1 are located, and the consequent miRNA down-regulation were detected only in HTLA-ER cells. This event correlated with BMI-1 oncoprotein up-regulation which caused a decrease in p16 tumor suppressor content and a metabolic adaptation of HTLA-ER cells. These results, taken collectively, highlight the role of miRNAs 15a/16-1 as markers of chemoresistance.
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http://dx.doi.org/10.1038/s41598-018-32195-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6137223PMC
September 2018

Matrine in association with FD‑2 stimulates F508del‑cystic fibrosis transmembrane conductance regulator activity in the presence of corrector VX809.

Mol Med Rep 2017 Dec 6;16(6):8849-8853. Epub 2017 Oct 6.

Department of Experimental Medicine, University of Genoa, I‑16132 Genoa, Italy.

Cystic fibrosis is caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and the predominant mutation is termed Phe508del (F508del). Therapy for F508del‑CFTR patients is based on the use of Orkambi®, a combination of VX809 and VX770. However, though Orkambi leads to an improvement in the lung function of patients, a progressive reduction in its efficacy has been observed. In order to overcome this effect, the aim of the present study was to investigate the role of matrine and the in‑house compound FD‑2 in increasing the action of VX809 and VX770. Fischer rat thyroid cells overexpressing F508del‑CFTR were treated with matrine, VX809 (corrector) and/or with a number of potentiators (VX770, FD‑1 and FD‑2). The results demonstrated that matrine was able to stimulate CFTR activity and, in association with FD‑2, increased the functionality of the channel in the presence of VX809. Based on these results, it may be hypothesized that FD‑2 may be a novel and more effective potentiator compared with VX770.
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http://dx.doi.org/10.3892/mmr.2017.7736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5779973PMC
December 2017

Glutathione-mediated antioxidant response and aerobic metabolism: two crucial factors involved in determining the multi-drug resistance of high-risk neuroblastoma.

Oncotarget 2016 Oct;7(43):70715-70737

Department of Experimental Medicine, University of Genova, Genova, Italy.

Neuroblastoma, a paediatric malignant tumor, is initially sensitive to etoposide, a drug to which many patients develop chemoresistance. In order to investigate the molecular mechanisms responsible for etoposide chemoresistance, HTLA-230, a human MYCN-amplified neuroblastoma cell line, was chronically treated with etoposide at a concentration that in vitro mimics the clinically-used dose. The selected cells (HTLA-Chr) acquire multi-drug resistance (MDR), becoming less sensitive than parental cells to high doses of etoposide or doxorubicin. MDR is due to several mechanisms that together contribute to maintaining non-toxic levels of H2O2. In fact, HTLA-Chr cells, while having an efficient aerobic metabolism, are also characterized by an up-regulation of catalase activity and higher levels of reduced glutathione (GSH), a thiol antioxidant compound. The combination of such mechanisms contributes to prevent membrane lipoperoxidation and cell death. Treatment of HTLA-Chr cells with L-Buthionine-sulfoximine, an inhibitor of GSH biosynthesis, markedly reduces their tumorigenic potential that is instead enhanced by the exposure to N-Acetylcysteine, able to promote GSH synthesis.Collectively, these results demonstrate that GSH and GSH-related responses play a crucial role in the acquisition of MDR and suggest that GSH level monitoring is an efficient strategy to early identify the onset of drug resistance and to control the patient's response to therapy.
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http://dx.doi.org/10.18632/oncotarget.12209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5342585PMC
October 2016

Redox Homeostasis and Cellular Antioxidant Systems: Crucial Players in Cancer Growth and Therapy.

Oxid Med Cell Longev 2016 21;2016:6235641. Epub 2016 Jun 21.

Department of Experimental Medicine, General Pathology Section, University of Genova, 16132 Genova, Italy.

Reactive oxygen species (ROS) and their products are components of cell signaling pathways and play important roles in cellular physiology and pathophysiology. Under physiological conditions, cells control ROS levels by the use of scavenging systems such as superoxide dismutases, peroxiredoxins, and glutathione that balance ROS generation and elimination. Under oxidative stress conditions, excessive ROS can damage cellular proteins, lipids, and DNA, leading to cell damage that may contribute to carcinogenesis. Several studies have shown that cancer cells display an adaptive response to oxidative stress by increasing expression of antioxidant enzymes and molecules. As a double-edged sword, ROS influence signaling pathways determining beneficial or detrimental outcomes in cancer therapy. In this review, we address the role of redox homeostasis in cancer growth and therapy and examine the current literature regarding the redox regulatory systems that become upregulated in cancer and their role in promoting tumor progression and resistance to chemotherapy.
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http://dx.doi.org/10.1155/2016/6235641DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4932173PMC
March 2017

Oxysterol mixture and, in particular, 27-hydroxycholesterol drive M2 polarization of human macrophages.

Biofactors 2016 Jan-Feb;42(1):80-92. Epub 2015 Dec 16.

Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy.

Macrophages play a crucial role in atherosclerosis progression. Classically activated M1 macrophages have been found in rupture-prone atherosclerotic plaques whereas alternatively activated macrophages, M2, localize in stable plaque. Macrophage accumulation of cholesterol and of its oxidized derivatives (oxysterols) leads to the formation of foam cells, a hallmark of atherosclerotic lesions. In this study, the effects of oxysterols in determining the functional polarization of human macrophages were investigated. Monocytes, purified from peripheral blood mononuclear cells of healthy donors, were differentiated into macrophages (M0) and treated with an oxysterol mixture, cholesterol, or ethanol, every 4 H for a total of 4, 8, and 12 H. The administration of the compounds was repeated in order to maintain the levels of oxysterols constant throughout the treatment. Compared with ethanol treatment, the oxysterol mixture decreased the surface expression of CD36 and CD204 scavenger receptors and reduced the amount of reactive oxygen species whereas it did not affect either cell viability or matrix metalloprotease-9 activity. Moreover, the oxysterol mixture increased the expression of both liver X receptor α and ATP-binding cassette transporter 1. An enhanced secretion of the immunoregulatory cytokine IL-10 accompanied these events. The results supported the hypothesis that the constant levels of oxysterols and, in particular, of 27-hydroxycholesterol stimulate macrophage polarization toward the M2 immunomodulatory functional phenotype, contributing to the stabilization of atherosclerotic plaques.
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http://dx.doi.org/10.1002/biof.1243DOI Listing
November 2016

Prevention of Lymphocyte Neurotoxic Effects by microRNA Delivery.

Microrna 2014 ;2(3):187-93

Department of Health Sciences, University of Genoa, Via A. Pastore 1, I-16132, Genoa, Italy.

Aicardi Goutieres Syndrome (AGS) is characterized by mutations occurring in genes encoding RNAses. AGS mutations silence intracellular RNases resulting in an intracellular overload of short RNAs arresting the physiological production of microRNA required for brain development. MiR-219 is typically down-regulated in Aicardi Goutieres Syn-drome (AGS). The goal of this study is to investigate miR-219 role in protecting astrocytes co-cultured with AGS-mutated lymphocytes. These lymphocytes display neurotoxic properties due to the presence of AGS-mutation and to their activa-tion by interpheron-alpha (IFN). Obtained results provide the evidence that astrocytes transfected with microRNA-219 are protected from the neurotoxic action of AGS lymphocytes activated by IFN-alpha. In particular, the miR-219 transfection increased astrocyte viability, growth, and differentiation while decreasing cell necrosis and apoptosis. Thus, microRNA-219 transfection is a valuable strategy in order to confer resistance to astrocytes towards lymphocyte-induced neurotoxici-ty especially in the presence of IFN-alpha, whose levels are typically increased in the cerebrospinal fluid of AGS patients.
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http://dx.doi.org/10.2174/22115366113029990010DOI Listing
April 2018

A novel mechanism for cyclic adenosine monophosphate-mediated memory formation: Role of amyloid beta.

Ann Neurol 2014 Apr 14;75(4):602-7. Epub 2014 Apr 14.

Department of Experimental Medicine, Section of General Pathology, University of Genoa, Genoa, Italy.

Cyclic adenosine monophosphate (cAMP) regulates long-term potentiation (LTP) and ameliorates memory in healthy and diseased brain. Increasing evidence shows that, under physiological conditions, low concentrations of amyloid β (Aβ) are necessary for LTP expression and memory formation. Here, we report that cAMP controls amyloid precursor protein (APP) translation and Aβ levels, and that the modulatory effects of cAMP on LTP occur through the stimulation of APP synthesis and Aβ production.
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http://dx.doi.org/10.1002/ana.24130DOI Listing
April 2014

HO-1 up-regulation: a key point in high-risk neuroblastoma resistance to bortezomib.

Biochim Biophys Acta 2014 Apr 28;1842(4):613-22. Epub 2013 Dec 28.

Department of Experimental Medicine, University of Genoa, 2, L.B. Alberti Street, I-16132 Genoa, Italy. Electronic address:

High-risk neuroblastoma (NB) is characterized by the development of chemoresistance, and bortezomib (BTZ), a selective inhibitor of proteasome, has been proposed in order to overcome drug resistance. Considering the involvement of the nuclear factor-erythroid-derived 2-like 2 (Nrf2) and heme oxygenase-1 (HO-1) in the antioxidant and detoxifying ability of cancer cells, in this study we have investigated their role in differently aggressive NB cell lines treated with BTZ, focusing on the modulation of HO-1 to improve sensitivity to therapy. We have shown that MYCN amplified HTLA-230 cells were slightly sensitive to BTZ treatment, due to the activation of Nrf2 that led to an impressive up-regulation of HO-1. BTZ-treated HTLA-230 cells down-regulated p53 and up-regulated p21, favoring cell survival. The inhibition of HO-1 activity obtained by Zinc (II) protoprophyrin IX (ZnPPIX) was able to significantly increase the pro-apoptotic effect of BTZ in a p53- and p21-independent way. However, MYCN non-amplified SH-SY5Y cells showed a greater sensitivity to BTZ in relation to their inability to up-regulate HO-1. Therefore, we have shown that HO-1 inhibition improves the sensitivity of aggressive NB to proteasome inhibition-based therapy, suggesting that HO-1 up-regulation can be used as a marker of chemoresistance in NB. These results open up a new scenario in developing a combined therapy to overcome chemoresistance in high-risk neuroblastoma.
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http://dx.doi.org/10.1016/j.bbadis.2013.12.008DOI Listing
April 2014

Role of glutathione in cancer progression and chemoresistance.

Oxid Med Cell Longev 2013 20;2013:972913. Epub 2013 May 20.

Department of Experimental Medicine, Section of General Pathology, Genoa, Italy.

Glutathione (GSH) plays an important role in a multitude of cellular processes, including cell differentiation, proliferation, and apoptosis, and disturbances in GSH homeostasis are involved in the etiology and progression of many human diseases including cancer. While GSH deficiency, or a decrease in the GSH/glutathione disulphide (GSSG) ratio, leads to an increased susceptibility to oxidative stress implicated in the progression of cancer, elevated GSH levels increase the antioxidant capacity and the resistance to oxidative stress as observed in many cancer cells. The present review highlights the role of GSH and related cytoprotective effects in the susceptibility to carcinogenesis and in the sensitivity of tumors to the cytotoxic effects of anticancer agents.
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http://dx.doi.org/10.1155/2013/972913DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3673338PMC
August 2014

Cyclic adenosine monophosphate as an endogenous modulator of the amyloid-β precursor protein metabolism.

IUBMB Life 2013 Feb 8;65(2):127-33. Epub 2013 Jan 8.

Department of Experimental Medicine, University of Genoa, Genoa, Italy.

Besides playing a pathogenic role in Alzheimer disease, amyloid-beta peptides are normally produced in low amounts in the brain, and several lines of evidence suggest that they can modulate synaptic plasticity and memory. As cyclic adenosine monophosphate (cAMP) is known to be involved in the same processes and the blockade of its degradation by phosphodiesterase 4 inhibitors has consistently shown beneficial effects on cognition, we investigated the possible correlation between this second messenger and Aβ peptides in neuronal N2a cells overexpressing the amyloid-β precursor protein (APP). We herein report that the elevation of endogenous cAMP by rolipram increased APP protein expression and both its amyloidogenic and nonamyloidogenic processing. The effects of rolipram were reproduced by both the cAMP membrane-permeant analog 8Br-cAMP and the forskolin-induced activation of adenylyl cyclase but were not affected by the PKA inhibitor H-89. Our results demonstrate that, in neuronal cells, APP metabolism is physiologically modulated by cAMP and suggest that this might represent an additional mechanism through which the second messenger could influence memory functions.
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http://dx.doi.org/10.1002/iub.1109DOI Listing
February 2013

Cholesterol and Alzheimer's disease: a still poorly understood correlation.

IUBMB Life 2012 Dec 2;64(12):931-5. Epub 2012 Nov 2.

Department of Experimental Medicine, University of Genoa, Genoa, Italy.

A large amount of evidence suggests a pathogenic link between cholesterol homeostasis dysregulation and Alzheimer's disease (AD). In cell culture systems, the production of amyloid-β (Aβ) is modulated by cholesterol, and studies on animal models have consistently demonstrated that hypercholesterolemia is associated with an increased deposition of cerebral Aβ peptides. Consequently, a number of epidemiological studies have examined the effects of cholesterol-lowering drugs (i.e., statins) in the prevention and the treatment of AD. However, while retrospective studies suggested a potential benefit of statin therapy, clinical trials produced inconsistent results. Here, we summarize the main findings from in vitro and in vivo research where the correlation between cholesterol and the neurodegenerative disorder was investigated. Recognition of this correlation could be an important step forward for our understanding of AD pathogenesis and, possibly, for the development of new therapeutic strategies.
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http://dx.doi.org/10.1002/iub.1091DOI Listing
December 2012

Short exposure of albumin to high concentrations of malondialdehyde does not mimic physiological conditions.

Exp Mol Pathol 2013 Feb 4;94(1):270-6. Epub 2012 Jul 4.

Department of Experimental Medicine, Section of General Pathology, University of Genova, Italy.

Malondialdehyde (MDA), a major lipid peroxidation product, spontaneously binds to, and modifies proteins. In vivo, proteins are physiologically exposed to micromolar MDA concentrations for long periods. In order to mimic this process in vitro, protein modification is often performed by short exposure to millimolar MDA concentrations, also in order to generate antigenic structures for antibody production. However, in our study, spectrophotometric and fluorimetric characteristics, electrophoretic migration, susceptibility to trypsin digestion and reactivity to antibodies indicated substantial differences between albumin incubated with millimolar MDA concentrations for a short period of time and albumin incubated with micromolar MDA concentrations for a long period of time. Therefore, our study showed that short incubation of albumin with millimolar MDA concentrations does not mimic the consequences of albumin exposure to long incubation with micromolar MDA concentrations. This casts doubts on the real possibility that antibodies, elicited with proteins modified with millimolar MDA concentrations for a short period, could detect all MDA-modified proteins in vivo. Moreover, natural antibodies against albumin, modified with micromolar MDA concentrations, have been detected in the serum of healthy blood donors, which appears to justify the existence of these kinds of modified proteins in vivo.
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http://dx.doi.org/10.1016/j.yexmp.2012.06.008DOI Listing
February 2013

Impaired synthesis contributes to diabetes-induced decrease in liver glutathione.

Int J Mol Med 2012 May 14;29(5):899-905. Epub 2012 Feb 14.

Department of Experimental Medicine, Section of General Pathology, University of Genova, Genova, Italy.

Diabetes-induced glutathione (GSH) decrease is usually ascribed to GSH oxidation. Here we investigate, in streptozotocin-treated rats, if impairment of GSH synthesis contributes to GSH decrease in diabetic liver, and if antioxidant treatments can provide protection. Diabetic rats were divided into 3 groups: untreated diabetic rats (UD); N-acetyl-cysteine (NAC)-treated diabetic rats; taurine (TAU)-treated diabetic rats; a group of non-streptozotocin-treated rats was used as control (CTR). All rats were sacrificed at 40 weeks of age. Diabetes induced hepatic glutathione decrease, but oxidized glutathione (GSSG) did not increase significantly. Accumulations of cysteine and cysteinyl-glycine in UD suggest respectively decreased glutathione synthesis and increased loss through the plasma membrane with subsequent degradation. Decreased expression of γ-glutamyl-cysteine synthetase in UD is consistent with repressed GSH synthesis. Moreover, diabetes caused increase of GSSG/GSH ratio and induction of heme oxygenase-1, both signs of oxidative stress. Supplementation with NAC or TAU resulted in amelioration of glutathione levels, probably depending on antioxidant activity, more efficient glutathione synthesis and decreased GSH loss and degradation. In conclusion, impaired synthesis and increased loss and degradation of GSH appear to contribute to a decrease in GSH levels in diabetic liver. NAC and TAU are able to partially protect from oxidative stress and GSH decrease, while enhancing GSH synthesis and restricting GSH loss.
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http://dx.doi.org/10.3892/ijmm.2012.915DOI Listing
May 2012

Resistance of neuroblastoma GI-ME-N cell line to glutathione depletion involves Nrf2 and heme oxygenase-1.

Free Radic Biol Med 2012 Jan 13;52(2):488-96. Epub 2011 Nov 13.

Department of Experimental Medicine, University of Genova, 16132 Genova, Italy.

Cancer cell survival is known to be related to the ability to counteract oxidative stress, and glutathione (GSH) depletion has been proposed as a mechanism to sensitize cells to anticancer therapy. However, we observed that GI-ME-N cells, a neuroblastoma cell line without MYCN amplification, are able to survive even if GSH-depleted by l-buthionine-(S,R)-sulfoximine (BSO). Here, we show that in GI-ME-N cells, BSO activates Nrf2 and up-regulates heme oxygenase-1 (HO-1). Silencing of Nrf2 restrained HO-1 induction by BSO. Inhibition of HO-1 and silencing of Nrf2 or HO-1 sensitized GI-ME-N cells to BSO, leading to reactive oxygen/nitrogen species overproduction and decreasing viability. Moreover, targeting the Nrf2/HO-1 axis sensitized GI-ME-N cells to etoposide more than GSH depletion. Therefore, we have provided evidence that in GI-ME-N cells, the Nrf2/HO-1 axis plays a crucial role as a protective factor against cellular stress, and we suggest that the inhibition of Nfr2/HO-1 signaling should be considered as a central target in the clinical battle against neuroblastoma.
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http://dx.doi.org/10.1016/j.freeradbiomed.2011.11.007DOI Listing
January 2012

Cholesterol and amyloid-β: evidence for a cross-talk between astrocytes and neuronal cells.

J Alzheimers Dis 2011 ;25(4):645-53

Department of Experimental Medicine, University of Genoa, Genoa, Italy.

Accumulating data supports the concept that alterations of cholesterol metabolism might influence the development of Alzheimer's disease (AD), a neurodegenerative disorder characterized by progressive accumulation of amyloid-β (Aβ) peptides in the brain. Changes in the neuronal production of Aβ have been described as a function of cholesterol levels, thus suggesting a causal link between cholesterol homeostasis dysregulation and AD pathogenesis. Under physiological conditions, cholesterol uptake in the brain is efficiently prevented by the blood-brain barrier, and mature neurons are thought to rely on glial cells for their cholesterol supply. In the present study, we tested the hypothesis that Aβ may serve as a signaling molecule capable of informing the astroglial network about the neuronal need for cholesterol. Collectively, our data bolster this hypothesis and demonstrate, for the first time, that Aβ(42) exerts an inhibitory effect on the expression of the cholesterol transporter ABCA1 in cultured astrocytes. Accordingly, we also show that ABCA1 expression is reduced in the brain of AβPP/PS1 transgenic mice. These results provide a biological function for Aβ peptides and may help to define the pathogenic relationship between cholesterol metabolism in brain and AD.
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http://dx.doi.org/10.3233/JAD-2011-110053DOI Listing
November 2011

PKCδ sensitizes neuroblastoma cells to L-buthionine-sulfoximine and etoposide inducing reactive oxygen species overproduction and DNA damage.

PLoS One 2011 Feb 7;6(2):e14661. Epub 2011 Feb 7.

Giannina Gaslini Institute, Genoa, Italy.

Neuroblastoma is a type of pediatric cancer. The sensitivity of neuroblastoma (NB) cancer cells to chemotherapy and radiation is inhibited by the presence of antioxidants, such as glutathione (GSH), which is crucial in counteracting the endogenous production of reactive oxygen species (ROS). We have previously demonstrated that cells depleted of GSH undergo apoptosis via oxidative stress and Protein kinase C (PKC) δ activation. In the present study, we transfected PKCδ in NB cells resistant to oxidative death induced by L-buthionine-S,R-sulfoximine (BSO), a GSH-depleting agent. Cell responses, in terms of ROS production, apoptosis and DNA damage were evaluated. Moreover, PKCδ activation was monitored by analyzing the phosphorylation status of threonine 505 residue, carrying out PKC activity assay and investigating the subcellular localization of the kinase. The cell responses obtained in BSO-resistant cells were also compared with those obtained in BSO-sensitive cells subjected to the same experimental protocol. Our results demonstrate, for the first time, that PKCδ induces DNA oxidation and ROS overproduction leading to apoptosis of BSO-resistant NB cells and potentiates the cytotoxic effects induced by BSO in sensitive cells. Moreover, PKCδ overexpression enhances the sensitivity of NB cells to etoposide, a well-characterised drug, commonly used in neuroblastoma therapy. Altogether our data provide evidence of a pro-oxidant role of PKCδ that might be exploited to design new therapeutic strategies aimed at selective killing of cancer cells and overcoming drug resistance. However, it becomes evident that a more detailed understanding of ROS-mediated signaling in cancer cells is necessary for the development of redox-modulated therapeutic approaches.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0014661PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3034714PMC
February 2011

Protein kinase C: an attractive target for cancer therapy.

Cancers (Basel) 2011 Feb 1;3(1):531-67. Epub 2011 Feb 1.

G. Gaslini Institute, L.go G. Gaslini 5, 16147, Genoa, Italy.

Apoptosis plays an important role during all stages of carcinogenesis and the development of chemoresistance in tumor cells may be due to their selective defects in the intracellular signaling proteins, central to apoptotic pathways. Consequently, many studies have focused on rendering the chemotherapy more effective in order to prevent chemoresistance and pre-clinical and clinical data has suggested that protein kinase C (PKC) may represent an attractive target for cancer therapy. Therefore, a complete understanding of how PKC regulates apoptosis and chemoresistance may lead to obtaining a PKC-based therapy that is able to reduce drug dosages and to prevent the development of chemoresistance.
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http://dx.doi.org/10.3390/cancers3010531DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3756376PMC
February 2011

Human mesangial cells resist glycoxidative stress through an antioxidant response.

Int J Mol Med 2011 Feb 6;27(2):213-9. Epub 2010 Dec 6.

Department of Experimental Medicine, University of Genoa, Genoa, Italy.

The generation of advanced glycation end-products (AGE), the interaction with their receptors, the generation of reactive oxygen species, and the modulation of intracellular redox equilibrium are believed to be the main factors causing alterations of mesangial cell physiology leading to diabetic nephropathy. Normal human primary mesangial cells were exposed to glycoxidative stress by culture in high glucose (HG) or treatment with AGE for up to 6 days. In both cases only a moderate generation of reactive oxygen species and production of HNE-protein adducts were induced while protein nitrotyrosination was not affected. Moreover, HG and AGE caused a significant antioxidant response, confirmed by the induction of heme oxygenase 1 and the consumption of vitamin E. Glutathione was decreased only by HG. Mesangial cell proliferation and viability were slightly affected by HG and AGE. Furthermore, both treatments failed to influence TGF-ß1 and MCP-1 secretion and to modulate RAGE and collagen IV expression. We believe that normal human mesangial cells can resist glycoxidative stress by the observed antioxidant response. These results support the concept that mesangial cells are only partly responsible for the onset and progression of diabetic nephropathy and that the role of other cell types, such as podocytes and endothelial cells, should be taken into consideration.
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http://dx.doi.org/10.3892/ijmm.2010.576DOI Listing
February 2011

DNA oxidative damage of neoplastic rat liver lesions.

Oncol Rep 2010 May;23(5):1241-6

Giannina Gaslini Institute, Genoa, Italy.

Hepatic lesions, experimentally-induced in Fisher 344 (F344) and Brown Norway (BN) rats, respectively, susceptible and resistant to liver carcinogenesis, progress differently to hepatocellular carcinoma (HCC). The mechanisms responsible for the acquisition of the resistant phenotype are not completely clear. Herein, we show that in F344 rats subjected to carcinogenic treatment, angiogenesis and DNA oxidation markers increase in preneoplastic and neoplastic liver lesions. On the contrary, in the HCCs of treated BN rats, angiogenesis and a minor DNA oxidation are accompanied by an attempt of tissue remodelling. This study suggests that DNA oxidation might be an important factor in the initiation and promotion of the events of hepatocarcinogenesis. On the other hand, the enhancement of GSH levels and the down-regulation of superoxide dismutase (SOD) expression in both rat strains suggest that antioxidant response is not involved in the acquisition of resistant phenotype.
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http://dx.doi.org/10.3892/or_00000756DOI Listing
May 2010

PKC delta and NADPH oxidase in retinoic acid-induced neuroblastoma cell differentiation.

Cell Signal 2010 May 13;22(5):828-35. Epub 2010 Jan 13.

Department of Experimental Medicine, University of Genoa, Italy.

The role of reactive oxygen species (ROS) in the regulation of signal transduction processes has been well established in many cell types and recently the fine tuning of redox signalling in neurons received increasing attention. With regard to this, the involvement of NADPH oxidase (NOX) in neuronal pathophysiology has been proposed but deserves more investigation. In the present study, we used SH-SY5Y neuroblastoma cells to analyse the role of NADPH oxidase in retinoic acid (RA)-induced differentiation, pointing out the involvement of protein kinase C (PKC) delta in the activation of NOX. Retinoic acid induces neuronal differentiation as revealed by the increased expression of MAP2, the decreased cell doubling rate, and the gain in neuronal morphological features and these events are accompanied by the increased expression level of PKC delta and p67(phox), one of the components of NADPH oxidase. Using DPI to inhibit NOX activity we show that retinoic acid acts through this enzyme to induce morphological changes linked to the differentiation. Moreover, using rottlerin to inhibit PKC delta or transfection experiments to overexpress it, we show that retinoic acid acts through this enzyme to induce MAP2 expression and to increase p67(phox) membrane translocation leading to NADPH oxidase activation. These findings identify the activation of PKC delta and NADPH oxidase as crucial steps in RA-induced neuroblastoma cell differentiation.
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http://dx.doi.org/10.1016/j.cellsig.2010.01.007DOI Listing
May 2010

Protein kinase C-dependent alpha-secretory processing of the amyloid precursor protein is mediated by phosphorylation of myosin II-B.

FASEB J 2009 Apr 22;23(4):1246-51. Epub 2008 Dec 22.

Department of Experimental Medicine, University of Genoa, Genoa, Italy.

A substantial body of evidence indicates that protein kinase C (PKC) is involved in the alpha-secretory processing of the amyloid precursor protein (APP), an event that reduces the formation of the pathogenic amyloid-beta peptide. Recently, we have shown that trafficking and processing of APP are both impaired by knockdown of myosin II-B, one of the major neuronal motor proteins. Here, we provide evidence that the alpha-secretory processing of APP is mediated by PKC-dependent phosphorylation of myosin II-B. This signaling pathway provides an important link between APP and the neuronal cytoskeleton and might be crucial for the understanding of the biological and pathological roles of APP.
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http://dx.doi.org/10.1096/fj.08-119263DOI Listing
April 2009