Biomedical subjects

G Fiorucci

Publications and source records attributed to G Fiorucci.

At least 19 recordsLinked to original sources

PubMed2005

TNF-related apoptosis-inducing ligand (TRAIL) as a pro-apoptotic signal transducer with cancer therapeutic potential.

The powerful inducer of apoptosis Apo2L/TNF-related apoptosis-inducing ligand (TRAIL) has generated exciting promise as a potential tumour specific cancer therapeutic agent, since it selectively induces apoptosis in transformed versus normal cells. Interferons (IFNs) are important modulators of TRAIL expression, thus the ligand appears to play an important role in surveillance against viral infection and malignant transformation. In the light of the emerging importance of TRAIL in cancer therapy, we will discuss the molecular basis of the cooperation of TRAIL and IFNs or chemotherapeutic drugs. In particular, we will focus on the data known to date concerning the biochemical pathways leading to TRAIL-induced apoptosis in specific cancer cells and warranting further work to enable the investigation in cancer patients.

Animals↗

PubMed2001

HIV-1 Nef activates STAT1 in human monocytes/macrophages through the release of soluble factors.

Monocytes/macrophages play a predominant role in the immunologic network by secreting and reacting to a wide range of soluble factors. Human immunodeficiency virus (HIV) infection leads to deep immunologic dysfunctions, also as a consequence of alterations in the pattern of cytokine release. Recent studies on in vivo models demonstrated that the expression of HIV Nef alone mimics many pathogenetic effects of HIV infection. In particular, Nef expression in monocytes/macrophages has been correlated with remarkable modifications in the pattern of secreted soluble factors, suggesting that the interaction of Nef with monocytes/macrophages plays a role in the pathogenesis of acquired immunodeficiency syndrome (AIDS). This study sought to define possible alterations in intracellular signaling induced by Nef in monocytes/macrophages. Results demonstrate that HIV-1 Nef specifically activates both alpha and beta isoforms of the signal transducer and activator of transcription 1 (STAT1). This was observed both by infecting human monocyte-derived macrophages (MDMs) with HIV-1 deletion mutants, and by exploiting the ability of MDMs to internalize soluble, recombinant Nef protein (rNef). STAT1-alpha activation occurs on phosphorylation of both C-terminal Tyr701 and Ser727 and leads to a strong binding activity. Nef-dependent STAT1 activation is followed by increased expression of both STAT1 and interferon regulatory factor-1, a transcription factor transcriptionally regulated by STAT1 activation. It was also established that Nef-induced STAT1- alpha/beta activation occurs through the secretion of soluble factors. Taken together, the results indicate that HIV-1 Nef could interfere with STAT1-governed intracellular signaling in human monocytes/macrophages.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Interferon-beta induces S phase slowing via up-regulated expression of PML in squamous carcinoma cells.

Type I Interferon (IFN) and all-trans retinoic acid (RA) inhibit cell proliferation of squamous carcinoma cell lines (SCC). Examinations of growth-affected cell populations show that SCC lines ME-180 and SiHa treated with IFN-beta undergo a specific slower progression through the S phase that seems to trigger cellular death. In combination treatment RA potentiates IFN-beta effect in SCC ME-180 but not in SiHa cell line, partially resistant to RA antiproliferative action. RA added as single agent affects cell proliferation differently by inducing a slight G1 accumulation. The IFN-beta-induced S phase lengthening parallels the increased expression of PML, a nuclear phosphoprotein specifically up-regulated at transcriptional level by IFN, whose overexpression induces cell growth inhibition and tumor suppression. We report that PML up-regulation may account for the alteration of cell cycle progression induced by IFN-beta in SCC by infecting cells with PML-PINCO recombinant retrovirus carrying the PML-3 cDNA under the control of the 5' LTR. In fact PML overexpression reproduces the IFN-beta-induced S phase lengthening. These findings provide important insight into the mechanism of tumor suppressing function of PML and could allow PML to be included in the pathways responsible for IFN-induced cell growth suppression.

Antineoplastic Agents↗

PubMed1999

Retinoic acid is able to induce interferon regulatory factor 1 in squamous carcinoma cells via a STAT-1 independent signalling pathway.

Interferon regulatory factor 1 (IRF-1) transcription factor binds to DNA sequence elements found in the promoters of type I IFN and IFN-inducible genes. Transient up-regulation of the IRF-1 gene by virus and IFN treatment causes the consequent induction of many IFN-inducible genes involved in cell growth control and apoptosis. We reported recently that IFN-alpha and all-trans retinoic Acid (RA) inhibit the cell proliferation of squamous carcinoma cell line ME-180 by inducing apoptotic cell death. IRF-1 expression correlates with the IFN-alpha-induced apoptosis phenomenon and, surprisingly, with the RA-induced apoptosis phenomenon. To study how these two different ligands cross-talk in the regulation of cellular antitumor responses, the signalling pathways involved in IRF-1 induction were analyzed in RA and/or IFN-alpha-treated ME-180 cells. We provide evidence indicating that RA-induced IRF-1 gene expression is independent of the STAT-1 activation pathway, despite the presence of the IFN-gamma activated sequence element in the gene promoter, but involves nuclear factor-kappaB activation. Thus, here we first describe the activation of nuclear factor-kappaB by both IFN-alpha and RA in the ME-180 cell line. The induced IRF-1 protein is successively able to bind the IFN-stimulated responsive element in the promoter of the target gene 2',5'-oligoadenylate synthetase.

Carcinoma, Squamous Cell↗

PubMed1998

Antiproliferative activity of interferon alpha and retinoic acid in SiHa carcinoma cells: the role of cell adhesion.

Several lines of evidence have demonstrated that IFNs could be relevant in the treatment of certain neoplastic diseases such as carcinomas. In particular, IFN-alpha, in addition to the anti-proliferative and cytostatic effects, was demonstrated to be capable of inducing cell death by apoptosis both in vivo and in vitro. Numerous protocols have also been proposed which consider the association of IFN-alpha with other drugs. Among these are retinoids, a class of compounds capable of inducing inhibition of cell growth and differentiation. We address the question here by analyzing the role of cell adhesion in susceptibility to IFN-alpha, RA and their combination of a human cell line derived from a squamous carcinoma of the cervix, the Bcl-2-negative SiHa cell line. In this context, cytoskeleton components and several surface molecules playing a role in cell substrate and cell-to-cell relationships have been evaluated. We found that RA treatment is capable of improving stress fiber formation, decreasing cell detachment and increasing cell-adhesion capability. However, no variations in the ability to adhere to specific extracellular-matrix molecules were found in RA-treated cells. No quantitative changes were detected in integrins involved as receptors for extracellular matrix molecules (VLAI-VLA5) or in other cell-adhesion-associated molecules (e.g., CD44). By contrast, 2 important molecules involved in cell-adhesion processes appeared to be up-regulated by RA exposure: focal adhesion kinase and E-cadherin, involved in adhesion plaque formation and cell-to-cell contacts, respectively. Keeping in mind the importance of adhesion properties in the cell-growth pathway, our findings could be of interest in the study of carcinoma-cell proliferation and metastatic potential.

Cadherins↗

PubMed1998

Apoptosis and growth inhibition of squamous carcinoma cells treated with interferon-alpha, IFN-beta and retinoic acid are associated with induction of the cyclin-dependent kinase inhibitor p21.

Recent studies have revealed promising leads on the potential of interferons (IFNs) in combination with retinoids in solid tumor therapy. The role of IFN-alpha and retinoic acid (RA) in cervical cancer is currently under active study. Because preclinical and clinical data on IFN-beta in combination with retinoids show promising results against breast carcinoma, we analysed the anti-proliferative effect of human recombinant IFN-beta alone or in combination with all-trans RA on two human squamous cervical carcinoma cell (SCC) lines (ME180 and SiHa). The two cell lines differ in their sensitivity to the anti-proliferative effects of the different agents and their combination: i) both cell lines were more responsive to IFN-beta than to IFN-alpha2b; ii) combined treatment with RA increases the growth inhibitory effect of the single agents in ME180, but not in SiHa; iii) the antiproliferative effect correlates with the induction of apoptosis. We suggest as a possible mechanisms of action that interferon regulatory factor-1 (IRF-1), a transcription factor which belongs to the IFN machinery, and the cyclin-dependent kinase inhibitor (CDKi) p21 can be involved in cellular growth inhibition and in the induction of apoptosis. These results support the use of IFN-beta in further clinical investigation possibly in combination with retinoids.

2',5'-Oligoadenylate Synthetase↗

PubMed1997

Retinoic acid and IFN inhibition of cell proliferation is associated with apoptosis in squamous carcinoma cell lines: role of IRF-1 and TGase II-dependent pathways.

Both retinoids and IFNs are known to inhibit proliferation of many normal and transformed cells and to have an in vivo antitumor effect against a variety of cancers, including squamous cell carcinoma. Because the combination of IFNs and all-trans retinoic acid (RA) could improve their antitumor effectiveness (depending on the histological origin and state of differentiation of the cells), we compared the activity of RA and/or IFN-alpha 2b with regard to the mechanism of growth inhibition of ME180 and SiHa cell lines, derived from squamous cervix carcinoma at different stages of differentiation. We reported previously that, in the ME180 cell line, the combined treatment significantly increased the growth inhibitory effect of the single agents. Here, we show that the SiHa cell line appears more sensitive to IFN-alpha 2b than the ME180 cell line, and resistant to RA, which does not significantly inhibit SiHa cell growth. Induction of apoptotic cell death clearly occurs and correlates with the inhibition of cell proliferation in both cell lines. It is interesting that the induction of the transcription factor IFN regulatory factor 1 correlates with the subsequent induction of apoptosis, whereas TGase I and II expression does not. In particular, TGase I and II appear differentially expressed in the ME180 and SiHa cell lines; i.e., TGase I is expressed in ME180 and specifically inhibited by RA, whereas TGase II is expressed in SiHa. It is interesting that both IFN-alpha and RA are able to increase TGase II expression and activity in this cell line.

Apoptosis↗

PubMed1996

CD26 surface molecule involvement in T cell activation and lymphokine synthesis in rheumatoid and other inflammatory synovitis.

T cell surface expression and the functional role of CD26 antigen (Ag), a surface ectoenzyme involved in T cell activation and migration across the extracellular matrix, were analyzed in the peripheral blood (PB) and synovial fluid (SF) from patients with inflammatory arthritides. CD26 membrane expression on T cells was detected by cytofluorometry using two different monoclonal antibodies, anti-Ta1 and anti-1F7, while cell proliferation and both IL-2 and IFN-gamma production were evaluated in anti-CD3- or anti-CD2-stimulated cell cultures after Ag surface modulation with anti-1F7. The results showed that Ta1 and 1F7 Ag expression were increased on T cells from PB of patients with active, but not inactive, rheumatoid arthritis (RA). Most SF T cells from RA or other inflammatory arthritides displayed the memory marker CD45R0 and the Ta1 Ag, but lacked the 1F7 molecule. In addition, in vitro 1F7 modulation, which enhanced RA PB T cell proliferation and both IL-2 and IFN-gamma synthesis, did not synergize with anti-CD3 or anti-CD2 in inducing IL-2-dependent activation of SF T cells, but reduced IFN-gamma production. A spontaneous reappearance of 1F7 Ag on the SF T cell surface was seen after 2-5 days in culture. Phorbol myristate acetate, able to accelerate its reexpression, also restored a normal response of SF T cells to anti-1F7 comitogenic effects. These data confirm a role of the CD26 surface molecule in regulating T cell activation and lymphokine synthesis. This observation may have important implications in the regulation of T cell activity at the joint level during chronic inflammatory processes.

Adult↗

PubMed1995

Interferon alpha-2b and retinoic acid combined treatment affects proliferation and gene expression of human cervical carcinoma cells.

The in vivo and in vitro antitumor effectiveness of IFNs is well documented. Their combination with differentiating agents, such as retinoic acid, has been demonstrated to be a promising therapy for patients with advanced squamous cell cancer of the skin and the cervix. However, the mechanisms that mediate these antitumor responses are not yet known. We studied the epidermoid cell line ME 180 derived from human cervical carcinoma to test its responsiveness to IFN-alpha-2b (INTRON A) and all-trans-retinoic acid (RA). Both agents have demonstrated ability to inhibit the growth of ME 180 cells in a dose- and time-dependent manner. The antiproliferative effect was further increased by the treatment with IFN-alpha-2b and RA combined. In accordance with this result, we found that the combination of the two agents has the effect of increasing the expression of the 2-5A synthetase gene, which is thought to play a key role in antigrowth responses to IFNs. At increased levels of 2-5A synthetase mRNA corresponds a significant increase in 2-5A synthetase activity. Although RA per se has no effect on the 2-5A synthetase expression, when it is combined with IFN-alpha-2b it appears to be able to potentiate the IFN-induced 2-5A synthetase expression. Moreover, the combination of IFN-alpha-2b and RA produces a similar effect also on the expression of the HLA-A2 gene, which has been shown to be induced in ME 180 cells both by IFN-alpha-2b and RA alone. In view of the possible mechanisms of action of the two agents, it is interesting to note that their combination increases, although transiently, the expression of IRF1, which codes for a transcription factor that regulates IFN gene expression and is thought to be involved in the regulation of IFN-induced effects and in mediating cell death or apoptosis.

2',5'-Oligoadenylate Synthetase↗

PubMed1995

Hemin inhibits the interferon-beta-induced antiviral state in established cell lines.

Hemin and other metalloporphyrins are known as very versatile compounds in nature, because they are able to carry out numerous functions in a free state or in association with specific proteins. When Friend murine erythroleukemia cells are treated with IFN-beta plus 100 microM hemin, the antiviral state is not observed, whereas the antiviral effect of IFN-gamma is unaffected by hemin treatment. This inhibitory effect of hemin is not restricted to erythroid cells. In fact, it is also observed in murine L929 and in human cell lines treated with IFN-beta. Neither trivalent iron in other forms nor hemin analogs (such as protoporphyrin IX or Sn(2+)-protoporphyrine IX) mimic this effect. Conversely, Co(3+)-protoporphyrin IX was as effective as hemin. At the transcriptional level, results obtained by run-on assays on nuclei from IFN-treated cells indicate that hemin does not completely inhibit IFN-beta induction of 2-5A synthetase gene(s) at 6 h of treatment but abolishes it at 24 h. In addition, hemin is able to inhibit the accumulation of IFN-induced 2-5A synthetase mRNAs. Experiments carried out to investigate the hemin effect on the early steps of the IFN signaling pathway indicate that hemin interferes with the ability of type I IFN to bind to its receptor, probably by a direct action on the IFN molecule.

Animals↗

PubMed1995

Inhibition of protein phosphorylation modulates expression of the Jak family protein tyrosine kinases.

Treatment of murine Friend cells with a dose of the protein kinase inhibitor staurosporine, which is able to block the response of the cells to interferons, appears to inhibit phosphorylation of Jak proteins and, interestingly, to specifically reduce tyk2 and Jak1 expression and to increase Jak2 both in the presence and in the absence of interferons. Therefore, a potential role for phosphorylation events in the regulation of expression of the Jak family members is suggested.

Alkaloids↗

PubMed1995

Long term treatment of rheumatoid arthritis with high doses of intravenous immunoglobulins: effects on disease activity and serum cytokines.

OBJECTIVE: To evaluate the effects of long term treatment of rheumatoid arthritis (RA) with high doses of intravenous immunoglobulins (IVIg). METHODS: Ten patients with active RA and prior unsuccessful treatment with at least one slow acting antirheumatic drug were treated with 400 mg/kg of IVIg for the first three days and then once a month for 12 months. Clinical evaluation and laboratory analysis were performed every month. Serum levels of tumour necrosis factor alpha (TNF alpha), soluble interleukin-2 receptor (sIL-2R), IL-1 alpha, IL-1 beta, IL-6 and interferon gamma (IFN gamma) were measured at baseline and at three monthly intervals for 15 months. RESULTS: Although laboratory parameters were not influenced by the treatment, a late but significant clinical improvement was observed after six months. Serial measurement of cytokines revealed a rapid and persistent decrease in serum TNF alpha and a late and significant reduction in sIL-2R concentrations. CONCLUSION: This study suggests that IVIg can ameliorate the symptoms and improve the functional capability of RA patients. This effect is associated with a partial modulation of serum concentrations of inflammatory cytokines and, more interestingly, with a late decrease in sIL-2R which correlated with the late reduction in disease activity.

Adult↗

PubMed1993

Activation of cord T lymphocytes. III. Role of LFA-1/ICAM-1 and CD2/LFA-3 adhesion molecules in CD3-induced proliferative response.

As cord T cells, a model of antigen (Ag)-unprimed cell, display a functional defect when stimulated through the CD3 molecule, the role of lymphocyte function-associated antigen 1(LFA-1)/intercellular adhesion molecule 1 (ICAM-1) and CD2/lymphocyte function-associated antigen 3 (LFA-3) receptor-ligand pairs in cord CD3-triggered T-cell activation was analyzed using specific monoclonal antibodies (mAb) against each adhesion molecule. The addition of anti-CD11a, anti-CD18, or anti-CD2 to both adult and cord peripheral blood mononuclear cells (PBMC) cultures led to a decrease in CD3-induced proliferation. In contrast, CD3-stimulated cord, but not adult, PBMC proliferation was markedly enhanced when anti-CD54 or anti-CD58 were added. Despite the fact that ICAM-1 and LFA-3 molecules were virtually absent on cord resting T cells, mAb against these two molecules boosted both mitogenesis of and interleukin (IL)-2 production by purified cord T cells stimulated with plastic immobilized anti-CD3. Cord T-cell supernatant levels of interferon-gamma (IFN-gamma) were undetectable with CD3 stimulation, slightly raised with CD58/CD3 costimulation, but normal when T cells were preincubated with IL-2 for 24 hr before being costimulated with anti-CD3/CD58. Evidence that IL-2 and IFN-gamma play a pivotal role in fully activating cord T cells came from the demonstration that IL-2 and IFN-gamma are able to bypass the CD3-proliferative defect through differential up-regulation of the adhesion molecules. It would, therefore, seem that ICAM-1 and LFA-3 molecules are crucially implicated in the CD3-activation pathway of Ag-unprimed T cells.

Adult↗

PubMed1992

Modulation of ferritin H-chain expression in Friend erythroleukemia cells: transcriptional and translational regulation by hemin.

The mechanisms that regulate the expression of the H chain of the iron storage protein ferritin in Friend erythroleukemia cells (FLCs) after exposure to hemin (ferric protoporphyrin IX), protoporphyrin IX, and ferric ammonium citrate (FAC) have been investigated. Administration of hemin increases the steady-state level of ferritin mRNA about 10-fold and that of ferritin protein expression 20-fold. Experiments with the transcriptional inhibitor actinomycin D and transfection studies demonstrate that the increment in cytoplasmic mRNA content results from enhanced transcription of the ferritin H-chain gene and cannot be attributed to stabilization of preexisting mRNAs. In addition to transcriptional effects, translational regulation induces the recruitment of stored mRNAs into functional polyribosomes after hemin and FAC administration, resulting in a further increase in ferritin synthesis. Administration of protoporphyrin IX to FLCs produces divergent transcriptional and translational effects. It increases transcription but appears to suppress ferritin mRNA translation. FAC treatment increases the mRNA content slightly (about twofold), and the ferritin levels rise about fivefold over the control values. We conclude that in FLCs, hemin induces ferritin H-chain biosynthesis by multiple mechanisms: a transcriptional mechanism exerted also by protoporphyrin IX and a translational one, not displayed by protoporphyrin IX but shared with FAC.

Animals↗

PubMed1992

Ethanol-induced CD3 and CD2 hyporesponsiveness of peripheral blood T lymphocytes.

The functional relevance of a direct ethanol effect on the membrane structure of T lymphocytes and accessory cells (APC), as well as on signal transduction systems was studied in ten normal subjects. Ethanol incubation (80 mM for 24h) of highly purified T cells increased the number of CD4+/CD45RA+ lymphocytes. In contrast, ethanol exposure induced a drop in CD14+/LFA-3+ APC values. These changes were accompanied by faulty T-cell proliferation in response to anti-CD3 and anti-CD2 mAb and inhibition of CD3- and CD2-mediated rises in intracellular calcium and, to a lesser extent, inositol 1,4,5-triphosphate levels. These data clearly indicate that a membrane-specific ethanol interaction both modifies surface glycoproteic and/or glycolipidic structures and alters transmembrane transduction of the activation signals.

Antibodies, Monoclonal↗

PubMed1991

Intracellular heme coordinately modulates globin chain synthesis, transferrin receptor number, and ferritin content in differentiating Friend erythroleukemia cells.

The effect of succinylacetone (SA), a highly specific inhibitor of ALA-dehydratase and heme synthesis, on hemoglobin (Hb) production, transferrin receptor (TfR), and ferritin expression was analyzed in differentiating Friend leukemia cells (FLC). This compound exerted a pronounced inhibitory effect not only on heme and Hb synthesis, but also on all the remaining above-mentioned parameters. In particular, SA induced: (1) a reduction of the level of alpha-globin mRNA; (2) a decreased number of exposed TfR molecules, without modification of their affinity for the ligand; (3) a reduced level of TfR RNA, without significant change of TfR gene transcription rate; and (4) a lower ferritin content. The addition of exogenous hemin to differentiating FLC exerted opposite effects, and particularly induced an increase of both the number of TfRs and ferritin content. These findings suggest that in erythroid cells optimal heme synthesis is required to coordinately sustain globin chains synthesis and TfR/ferritin production; thus, the intracellular heme level may represent a key regulatory factor in the Hb synthesis pathway.

Cell Differentiation↗

PubMed1991

Positive modulation of hemoglobin, heme, and transferrin receptor synthesis by murine interferon-alpha and -beta in differentiating Friend cells. Pivotal role of heme synthesis.

Administration of highly purified preparations of murine interferon (IFN)-alpha 1, -alpha 4, -alpha 6, or -beta to Friend leukemia cells induced to differentiate by dimethyl sulfoxide leads to a 100% increase of benzidine-positive (B+) cells. Different efficiencies for the two IFN species have been observed; a 10-fold higher dose of IFN-alpha is needed for stimulation of hemoglobin production and inhibition of cell growth as compared with IFN-beta. Both species of IFN induce a substantial increase in heme, hemoglobin, and transferrin receptor levels. In vitro run-on transcription assays indicate that IFN-beta moderately stimulates transcription of the alpha-globin gene but not the transferrin receptor gene. It is postulated that IFN induces the enhancing effect on differentiation via a marked increase of heme synthesis and number of transferrin receptors, which in turn leads to an enhancement of globin chain synthesis. In this regard, the negative feedback reported in a variety of other cell types for the regulation of transferrin receptor expression by heme does not seem to be operative in maturing Friend erythroleukemia cells, which present evidence for a positive mechanism.

Animals↗

PubMed1991

Protein binding to the interferon response enhancer correlates with interferon induction of 2'-5'-oligoadenylate synthetase in normal and interferon-resistant Friend cells.

The induction of transcription of the 2'-5'-oligoadenylate (2-5A) synthetase gene by type I (alpha/beta) and type II (gamma) interferons (IFNs) has been studied in wild-type (w.t.) and IFN-resistant Friend leukemia cells (FLC). Following IFN treatment, new complexes are formed in vitro between the IFN-responsive sequence (IRS) of the 2-5A synthetase gene and cellular proteins. Within minutes after IFN-alpha/beta addition to w.t. FLC, an IRS-protein complex, designated F1, is detected, as already observed in several human cell lines. In response to IFN-gamma, a novel complex, designated Fg, is observed in w.t. FLC. The Fg complex appears within 3 h, while an F1-like complex is faintly visible 10 to 24 h later. In the IFN-alpha/beta-resistant FLC, IFN-gamma induces only the Fg complex and fails to induce F1. Fg formation is correlated with the IFN-gamma-induced transcription of the 2-5A synthetase gene and the appearance of the corresponding enzymatic activity in both w.t. and IFN-alpha/beta-resistant FLC. These findings suggest that F1 and Fg represent two distinct effector complexes by which type I and type II IFNs, respectively, induce 2-5A synthetase.

2',5'-Oligoadenylate Synthetase↗