A. Arcangeli | Università degli Studi di Firenze (University of Florence) (original) (raw)

Papers by A. Arcangeli

MicroRNAs (miRs) are small non-coding RNAs that regulate gene expression. miR-21 plays an importa... more MicroRNAs (miRs) are small non-coding RNAs that regulate gene expression. miR-21 plays an important role in cancer (including leukemia1) drug resistance2. It has recently been reported to directly target and upregulate the expression of Bcl-23. AntimiRs are used to downregulate the expression of targeted miRs and some are already in clinical trials for treatment of certain diseases. The aim of this work was to use antimiRs to downregulate miR-21 expression in K562 chronic myeloid leukemia cells, in order to increase the sensitivity of these cells to conventional drugs and to further investigate the mechanisms involved in this sensitization. K562 cells were transfected with antimiR-21 and in some experiments further treated with etoposide or doxorubicin (appropriate controls were included). Downregulation of miR-21 levels was confirmed by RT-qPCR. The effect of miR downregulation on cellular proliferation (BrdU assay), cell cycle (flow cytometry following PI labeling) and programmed ...

British Journal of Cancer, 2001

documented clinical responses ranging from 8.7% (2 cases out of 23) to 57% (4 cases out of 7), Co... more documented clinical responses ranging from 8.7% (2 cases out of 23) to 57% (4 cases out of 7), Covens (Covens et al, 1997) and Markman (Markman et al, 1997) did not observe any response. In any case, all the trials were performed in patients affected by recurrent or metastatic endometrial cancer, while a study on the use of LHRH analogues as a primary treatment for this type of cancer is currently lacking. Moreover, no data on the LHRH receptor status was reported in the above-cited studies. In this study, we report the case of a patient affected by endometrial cancer and treated primarily with LHRH analogue, the surgical approach being unfeasible due to her compromised health. The therapy was carried on for more than 6 years, and no progression of the disease was observed. During this period, some histological and immunohistochemical evaluations of the tumour, including morphology, grading, proliferating index and apoptotic power, were performed. Moreover, the expression of m-RNA for LHRH receptors was determined.

European Journal of Surgical Oncology, 2019

Background: In search of novel prognostic biomarkers for clear cell renal carcinoma (ccRCC), we a... more Background: In search of novel prognostic biomarkers for clear cell renal carcinoma (ccRCC), we analysed the expression of several proteins related to angiogenesis and hypoxia. Methods: A monocentric study on 30 consecutive surgical samples from surgically-treated ccRCC patients with a 10-year follow up was performed. The following proteins were analysed by immunohistochemistry: Vascular Endothelial Growth Factor-A (VEGF-A), Platelet-Derived Growth Factor b Receptor (PDGFRb), VEGF-receptor 1 (Flt1), VEGF-receptor 2 (KDR), Glucose Transporter 1 (GLUT1), Carbonic anhydrase IX (CA-IX) and the hERG1 potassium channel. Data were analysed in conjunction with the clinico-pathological characteristics of the patients and follow up. Results: All the proteins were expressed in the samples, with statistically significant associations of VEGF-A with PDGFRb and Flt1 and hERG1 with CA IX. Notably, hERG1 and CAIX co-immunoprecipitated in primary ccRCC samples and survival analysis showed that the positivity for hERG1 and CA IX had a negative impact on Recurrence Free Survival (RFS) at the univariate analysis. At the multivariate analysis only hERG1 maintained its statistically significant negative impact. Conclusions: hERG1 expression can be exploited to predict recurrence in surgically-treated ccRCC patients. hERG1 channels form a multiprotein complex with the pH regulator CA IX in primary ccRCC samples their potential use as therapeutic target might be suggested.

British Journal of Cancer, 2000

HERG K + channels, besides contributing to regulate cardiac and neuronal excitability, are prefer... more HERG K + channels, besides contributing to regulate cardiac and neuronal excitability, are preferentially expressed in tumour cell lines of different histogenesis, where their role in the development and maintenance of the neoplastic phenotype is under study. We show here that both herg gene and HERG protein are expressed with high frequency in primary human endometrial cancers, as compared to normal and hyperplastic endometrium. RT-PCR and immunohistochemistry, using specific anti-HERG antibodies developed in our laboratory, were applied to tissue specimens obtained from 18 endometrial cancers and 11 non-cancerous endometrial tissues. herg RNA and HERG protein are expressed in 67% and 82%, respectively, of cancerous, while in only 18% of non-cancerous tissues. In particular, no expression was found in endometrial hyperplasia. Moreover, electrophysiological experiments confirmed the presence of functioning HERG channels on the plasma membrane of tumour cells. On the whole, these data are the first demonstration of the presence of HERG channels in primary human neoplasias, and could candidate HERG as a potential tool capable of marking cancerous versus hyperplastic endometrial growth.

British journal of cancer, Jan 9, 2014

A subset of human hepatocellular carcinomas (HCC) exhibit mutations of β-catenin gene CTNNB1 and ... more A subset of human hepatocellular carcinomas (HCC) exhibit mutations of β-catenin gene CTNNB1 and overexpress Glutamine synthetase (GS). The CTNNB1-mutated HCC cell line HepG2 is sensitive to glutamine starvation induced in vitro with the antileukemic drug Crisantaspase and the GS inhibitor methionine-L-sulfoximine (MSO). Immunodeficient mice with subcutaneous xenografts of the CTNNB1-mutated HCC cell lines HepG2 and HC-AFW1 were treated with Crisantaspase and/or MSO, and tumour growth was monitored. At the end of treatment, tumour weight and histology were assessed. Serum and tissue amino acids were determined by HPLC. Gene and protein expression were estimated with RT-PCR and western blot and GS activity with a colorimetric method. mTOR activity was evaluated from the phosphorylation of p70S6K1. Crisantaspase and MSO depleted serum glutamine, lowered glutamine in liver and tumour tissue, and inhibited liver GS activity. HepG2 tumour growth was significantly reduced by either Crisan...

Cancer research, Jan 15, 1998

The human ether-a-go-go-related gene (herg) encodes a K+ current (IHERG) that plays a fundamental... more The human ether-a-go-go-related gene (herg) encodes a K+ current (IHERG) that plays a fundamental role in heart excitability by regulating the action potential repolarization (IKr); mutations of this gene are responsible for the chromosome 7-linked long QT syndrome (LQT2). In this report, we show that in a variety (n = 17) of tumor cell lines of different species (human and murine) and distinct histogenesis (neuroblastoma, rhabdomyosarcoma, adenocarcinoma, lung microcytoma, pituitary tumors, insulinoma beta-cells, and monoblastic leukemia), a novel K+ inward-rectifier current (IIR), which is biophysically and pharmacologically similar to IHERG, can be recorded with the patch-clamp technique. Northern blot experiments with a human herg cDNA probe revealed that both in human and murine clones the very high expression of herg transcripts can be quantified in at least three clearly identifiable bands, suggesting an alternative splicing of HERG mRNA. Moreover, we cloned a cDNA encoding f...

Proceedings of the National Academy of Sciences, 1993

The mechanism of action of polar/apolar inducers of cell differentiation, such as dimethyl sulfox... more The mechanism of action of polar/apolar inducers of cell differentiation, such as dimethyl sulfoxide and hexamethylene-bisacetamide, is still obscure. In this paper evidence is provided that their effects on murine erythroleukemia cells are modulated by various extracellular cations as a precise function of the cation effects on membrane surface potential. The interfacial effects of the inducers were directly measured on the charged electrode, showing that both dimethyl sulfoxide and hexamethylene-bisacetamide, at the effective concentrations for cell differentiation and within the physiological range of charge density, adsorb at the charged surface and produce a potential shift. A linear correlation was found between this shift and the inducer effects on cell differentiation. Besides offering a different interpretation of the mechanism of action of the inducers, these findings indicate that surface potential has a signaling function. They may also be relevant to cancer treatments b...

Molecular and Cellular Biology, 2008

A common feature of tumor cells is the aberrant expression of ion channels on their plasma membra... more A common feature of tumor cells is the aberrant expression of ion channels on their plasma membrane. The molecular mechanisms regulating ion channel expression in cancer cells are still poorly known. K + channels that belong to the human ether-a-go-go-related gene 1 ( herg1 ) family are frequently misexpressed in cancer cells compared to their healthy counterparts. We describe here a posttranslational mechanism for the regulation of hERG1 channel surface expression in cancer cells. This mechanism is based on the activity of hERG1 isoforms containing the USO exon. These isoforms (i) are frequently overexpressed in human cancers, (ii) are retained in the endoplasmic reticulum, and (iii) form heterotetramers with different proteins of the hERG family. (iv) The USO-containing heterotetramers are retained intracellularly and undergo ubiquitin-dependent degradation. This process results in decreased hERG1 current (I hERG1 ) density. We detailed such a mechanism in heterologous systems and...

Leukemia, 2002

An important target in the understanding of the pathogenesis of acute myeloid leukemias (AML) rel... more An important target in the understanding of the pathogenesis of acute myeloid leukemias (AML) relies on deciphering the molecular features of normal and leukemic hemopoietic progenitors. In particular, the analysis of the mechanisms involved in the regulation of cell proliferation is decisive for the establishment of new targeted therapies. To gain further insight into this topic we report herein a novel approach by analyzing the role of HERG K + channels in the regulation of hemopoietic cell proliferation. These channels, encoded by the human ether-agò-gò-related gene (herg), belong to a family of K + channels, whose role in oncogenesis has been recently demonstrated. We report here that herg is switched off in normal peripheral blood mononuclear cells (PBMNC) as well as in circulating CD34 + cells, however, it is rapidly turned on in the latter upon induction of the mitotic cycle. Moreover, herg appears to be constitutively activated in leukemic cell lines as well as in the majority of circulating blasts from primary AML. Evidence is also provided that HERG channel activity regulates cell proliferation in stimulated CD34 + as well as in blast cells from AML patients. These results open new perspectives on the pathogenetic role of HERG K + channels in leukemias.

Leukemia, 2000

Although dephosphorylation of tyrosine containing proteins is considered a necessary step in the ... more Although dephosphorylation of tyrosine containing proteins is considered a necessary step in the induction of leukemia cell differentiation by hybrid polar compounds (HPC), the crucial actors in this step remain unknown. We present evidence that tyrosine phosphorylation of JAK1 and JAK2 is down-regulated in murine erythroleukemia cells (MELC) within the first 6 h of their exposure to the prototype of the HPC family, hexamethylenebisacetamide (HMBA), with full recovery at 14 h. Further evidence that the JAKs-centered signalling pathway is switched off early by HMBA was provided by the demonstration that STAT5, a downstream member of this pathway, turned out to be completely dephosphorylated at 6 h in HMBA-treated cells. This JAKs dephosphorylation did not occur in HMBAresistant clones, suggesting that JAKs are possible targets of the dephosphorylative process required for leukemia cell commitment to differentiation. These results may have impact on leukemia therapy based on JAKs inhibitors. Leukemia (2000) 14,

Journal of Biological Chemistry, 2000

Journal of Biological Chemistry, 2007

Expression of c-MET, the HGF (hepatocyte growth factor) tyrosine kinase receptor, was investigate... more Expression of c-MET, the HGF (hepatocyte growth factor) tyrosine kinase receptor, was investigated in pediatric B-acute lymphoblastic leukemia (ALL) patients. c-MET was found to be expressed in normal B cells and in BALL patients with the t(12;21) TEL-AML1 translocation, but it is not expressed in the most part of BALL without the t(12;21). We also found that c-MET, related to proliferation and protection from apoptosis, is associated with the pro-apoptotic pro-teinFASinTEL-AML1B-ALLcellsandinnormalBlymphocytes.The possible role of this protein complex in drug-induced apoptosis was thus investigated in REH TEL-AML1 BALL cell line. REH cells prestimulated with HGF and treated with doxorubicin had shown a higher apoptotic rate than non-HGF-prestimulated ones (p ‫؍‬ 0.03). REH cells stimulated with IL-3 and treated with doxorubicin did not undergo apoptosis more than nonstimulated cells, demonstrating that increased proliferation in itself is not directly related to the higher apoptotic sensitivity observed with HGF stimulation. These results indicate that c-MET activation enhances specifically FAS-mediated apoptosis in TEL-AML1 ALL cells and, considering that the c-MET/FAS complex is present only in normal B lymphocytes and in TEL-AML1 leukemias, this implies that it may have an important contribution in cellular homeostasis and in high sensitivity of TEL-AML1 ALL to chemotherapeutic regimens. Acute lymphoblastic leukemia (ALL) 2 is the most common form of childhood cancer and is the primary cause of cancer-related mortality in children (1). ALL is a disorder in which failure of differentiation, overproliferation, and a defective apoptosis in a clonal cell compartment result in accumulation of aberrant cells. Modifications in key cellular genes, such as growth factor, death receptor, and transcription factor genes, underpin the basis of leukemogenesis. These genetic modifications could result in a series of acquired defects that allow the developing cancer cell to grow unchecked and resist to drug cytotoxic effects (2). The tyrosine kinase c-MET is the high affinity receptor for HGF/SF (hepatocyte growth factor/scatter factor), a multifunctional cytokine with pleiotropic effects (3, 4). After HGF binding, c-MET undergoes autophosphorylation at tyrosine residues Tyr 1234 and Tyr 1235 , creating a multifunctional docking site for several proteins including Grb2, PI3K, PLC␥, SHP-2, and STAT3. Signaling via this pathway has been shown to affect a wide range of biological activities including cell motility, growth, proliferation, and protection from apoptosis. Thus, uncontrolled HGF/c-MET signaling triggers a unique biological program conferring metastatic properties to cancer cells (5-8). In a wide variety of epithelial cancers, alterations of c-MET activity because of mutations, overexpression or coexpression with HGF had been well-described (for a review see Ref. 9). Remarkably, coordinated control of the HGF/c-MET pathway is also important in vertebrate development. Mouse knockout experiments result in embryonic death because of defects in epithelial cell-based organs and nervous system formation (10). c-MET has been detected also in hematopoietic cells such as human CD34ϩ hemopoietic progenitor cells (11), and it seems to play an important role in regulation of antigen-specific B-cell differentiation (12). Moreover, the HGF/c-MET signaling pathway was observed to be involved in development and progression of hematological neoplasias including Burkitt lymphomas * This work was supported by grants from the Programmi di Ricerca di Interesse Nazionale (PRIN) (to G.B. and A.A.), the Associazione Italiana per la Ricerca sul Cancro (AIRC) (to G.B. and A.A.), the Consiglio Nazionale delle Ricerche (Progetto Oncologia) (CNR) (to G.B.), the Fondazione Città Della Speranza (to G.B.), the Ministero dell'Istruzione dell'Università e della Ricerca (MIUR) (to G.B.), the Fondazione Cariplo (to G.B.), the Associazione Italiana contro le Leucemie (AIL) (Firenze and Pistoia sections) (to S.P.), the Ente Cassa di Risparmio Firenze (to A.A.), and the Associazione Genitori contro le Leucemie e Tumori Infantili Noi per Voi (to A.A.

European Journal of Surgical Oncology (EJSO), 2014

Purpose: The clinical significance of VEGF-A expression in gastric cancer (GC) has been reported ... more Purpose: The clinical significance of VEGF-A expression in gastric cancer (GC) has been reported with contradicting results. We analyzed the expression and clinical significance of VEGF-A in a wide Italian cohort of GC specimens. Methods: VEGF-A expression was tested by immunohistochemistry in 507 patients with GC of all clinical stages. The impact of VEGF-A on overall survival (OS) was evaluated in conjunction with clinical and pathological parameters. Results: In the Italian cohort we studied VEGF-A was not an independent prognostic factor neither at the univariate nor at multivariate analysis. Conclusions: Although frequently expressed, in our study VEGF-A was not able to discriminate between groups of patients with different risk.

Biophysical Journal, 1992

The properties of low (LVA) and high (HVA) voltage-activated calcium currents were investigated i... more The properties of low (LVA) and high (HVA) voltage-activated calcium currents were investigated in rat sensory neurons and a murine neuroblastoma cell line exposed to various concentrations of intraor extracellular monovalent ([c+] i/o) and trivalent ([c3+]i]o) cations. In neurons, when [c+]i was changed from 150 to 20 mM, positive shifts of 18-28 mV were observed in activation curves of both LVA and HVA currents, as well as in LVA inactivation curves. Extracellularly, in divalent-free solutions, [c+]o of 20-50 mM produced medium (12-22 mV) negative shifts of the LVA channel properties. These data were used to estimate, by a "screening" model, a negative surface charge density around neuron's calcium channels of 1/1,000 and 1/1,325 eA-2 at the outside or inside face, respectively. In the presence of physiological concentrations of divalent cations, [c+]0 of 20-60 mM caused smaller (4-11 mV) negative shifts of the activation and inactivation curves, which can be explained by assuming a partial neutralization of negative charges by divalent cations. By applying the above procedure to LVA channels of neuroblastoma cells, the ratio of extra-to intracellular surface charge density turned out to be more than tenfold higher than in neurons. Effects produced by [c3+] i1o were not in agreement with expectations based on screening or binding models.

Toxicologic Pathology, 1984

Several studies are reviewed dealing with the mechanisms which regulate the cell cycle progressio... more Several studies are reviewed dealing with the mechanisms which regulate the cell cycle progression in normal and cancer cells. Using Yoshida A H 130 ascites tumor cells, it has been found that the GI-S transition of these cells i s impaired by specific inhibitors of the electron flow through the respiratory chain (antimycin A), although respiratory ATP can be replaced by glycolytic ATP. The above transition can be also inhibited by the addition of physiologic substrates, mainly pyruvate, by a mechanism which appears linked to a modification of the cellular redox state and can be totally reversed by adding adenine to the culture medium. Adenine equally removes the block produced by antimycin A, pointing out a respiration-linked step of purine metabolism restricting the cell recruitment into S. A substantial protection of this step against the inhibitory effects of pyruvate and antimycin A has been obtained by the addition of folate and tetrahydrofolate, suggesting that the respiration-linked limiting step of tumor cell cycling involves folate metabolism and its connection to purine synthesis. The biologic relevance of these findings i s stressed by the fact that pyruvate addition also inhibits the proliferation of concanavalin A-stimulated lymphocytes as well as of bone marrow hemopoietic cells in the presence of colonystimulating factors. On the other hand, pyruvate only slightly affects the growth kinetics of malignant lymphoblasts and of Friend erythroleukemia cells either i n the absence or in the presence of the differentiation inducer dimethylsulfoxide.

Blood Cancer Journal, 2016

Annals of the Rheumatic Diseases, 2014

ABSTRACT Background The lymphatic system has been proposed as the possible link between inflammat... more ABSTRACT Background The lymphatic system has been proposed as the possible link between inflammatory bowel disease and spondyloarthropathy (SpA), which both display lymphedema and lymphangiogenesis. Nevertheless, the role of the lymphatic system in the connection between SpA and Crohn's disease (CD) still remains to be elucidated Objectives To investigate the circulating levels of lymphatic endothelial progenitors cells (L-EPC) and their possible correlation with disease duration and activity indices in SpA, CD and SpA associated with CD (SC). Methods Peripheral blood samples from patients affected by SpA (n=33), CD (n=25) and SC (n=20) and from 20 age- and sex-matched healthy controls were collected and used for quantification of circulating L-EPC. L-EPC were identified by FACS using anti-CD34 FITC-conjugated, anti-CD133 APC-conjugated and anti-VEGFR-3 PE-conjugated antibodies. L-EPC counts were reported as absolute number per 2x105 mononuclear cells and results were expressed as a percentage of total mononuclear cells. The correlation between L-EPC levels and disease duration (< or >10 years) and BASDAI for SpA or CDAI for CD was analyzed. Results The number of L-EPC was significantly increased in CD (mean 4.69% ±9.9, p<0.004), SpA (9.24% ±11.2, p<0.005) and SC (5.42% ±4.5, p<0.01) patients compared with controls (2.0% ±1.89). In CD patients, a significant correlation was observed between L-EPC counts and disease duration, with significantly higher levels in earlier phases (p<0.03). L-EPC levels did not correlate either with BASDAI nor with CDAI. Conclusions The increase of L-EPC levels in SpA, CD and SC observed in our study clearly indicate an active mobilization of lymphatic cell precursors. In particular, in CD, L-EPC mobilization may be related to the lymphangiogenesis process occurring in the first phases of the disease. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4297

The Biochemical journal, Jan 15, 1988

The present study deals with changes in ether-linked glycerophospholids which accompany different... more The present study deals with changes in ether-linked glycerophospholids which accompany differentiation of Friend erythroleukaemia (FEL) cells by dimethyl sulphoxide (DMSO) and hexamethylenebisacetamide (HMBA). We also tested clones of FEL cells non-inducible by DMSO or HMBA for ether-linked lipid changes not related to the differentiation process. FEL cells contained appreciable proportions of alkenylacyl and alkylacyl subfractions in phosphatidylethanolamine (PE) and phosphatidylcholine (PC). Compared with FEL cells, clones non-inducible by DMSO or HMBA had a greater amount of alkenylacyl PE associated with a lack of alkenylacyl PC. The differentiation of FEL cells by DMSO or HMBA was accompanied by a reduction of alkylacyl PE and PC. DMSO- and HMBA-differentiated FEL cells showed changes in alkenyl- and alkyl-chain profiles, some of which were also observed in non-inducible FEL cells treated with DMSO or HMBA.

The Journal of physiology, 1995

1. Human and murine neuroblastoma cell lines were used to investigate, by the whole-cell patch-cl... more 1. Human and murine neuroblastoma cell lines were used to investigate, by the whole-cell patch-clamp technique, the properties of a novel inward-rectifying K+ current (IIR) in the adjustment of cell resting potential (Vrest), which was in the range -40 to -20 mV. 2. When elicited from a holding potential of 0 mV, IIR was completely inactivated with time constants ranging from 13 ms at -140 mV to 4.5 s at -50 mV. The steady-state inactivation curve (h(V)) was found to be independent of [Na+]o and [K+]o (2-80 mM) and could be fitted to a Boltzmann curve with a steep slope factor of 5-6, and a V1/2 around Vrest. Divalent ion-free extracellular solutions shifted h(V) to the left by about 28 mV. 3. Peak chord conductance, whose maximal value was approximately proportional to the square root of [K+]o, could be fitted to a Boltzmann curve independently of [K+]o, with a V1/2 value around -48 mV and a slope factor of 18. Extracellular Cs+ and Ba2+ blocked the IIR in a concentration- and volt...

Trends in cell biology, 2006

Integrin receptors mediate adhesion of the cell to the extracellular matrix and thereby regulate ... more Integrin receptors mediate adhesion of the cell to the extracellular matrix and thereby regulate cell motility, proliferation, differentiation and apoptosis. These processes are frequently accompanied by alterations in ion flow. Recent evidence suggests that integrins can regulate ion channels and form macromolecular complexes, thus contributing to the localization of the channel onto the plasma membrane. The integrin-channel complex regulates downstream signaling proteins, such as tyrosine kinases and GTPases. This process could occur in plasma membrane microdomains, such as caveolae. It seems that ion channels sometimes transmit their signals through conformational coupling, instead of change in ion fluxes. Finally, the channel protein is not merely a final target, because it often feeds back by controlling integrin activation and/or expression. These findings have important implications for the physiology of normal and neoplastic cells and suggest interesting perspectives for stu...