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M Grazia Cifone

Publications and source records attributed to M Grazia Cifone.

6 recordsLinked to original sources
PubMed2003

Sphingolipids and the immune system.

The importance of sphingolipids, not only as components of plasma membranes but also as key players in different physiological and pathophysiological cellular events, is now emerging. This review gathers together what the authors feel are the most relevant data, present in the literature, regarding the roles and the effects of sphingolipids, such as ceramide, ceramide-1-phosphate (C1P), sphingosine (SP) and sphingosine-1-phosphate (S1P), on the development, activation and regulation of the immune system.

Animals↗
PubMed1997

NKR-P1A stimulation of arachidonate-generating enzymes in rat NK cells is associated with granule release and cytotoxic activity.

NKR-P1A protein has been implicated in the triggering of NK-mediated natural killing contributing to target cell recognition by NK cells. The aim of the present work was to assess whether NKR-P1A receptor triggering also induced arachidonic acid (AA) generation and to determine the possible role of this event on granule release and cytotoxicity. We demonstrated that activation of fresh peripheral blood rat NK cells by cross-linking with the anti-NKR-P1A 3.2.3 mAb induced calcium-dependent AA release, which is due to the activation of cytosolic phospholipase A2 (cPLA2), secretory phospholipase A2 (sPLA2), and diacylglycerol/monoacylglycerol lipase. We also documented the presence of a type II sPLA2 activity in the supernatant fluids from NKR-P1A-activated rat NK cells, suggesting that AA and lysophospholipids could be mobilized from the outside of the cell. The involvement of AA-generating enzymes in NKR-P1A-induced cytotoxic functions was also investigated. Treatment of effector cells with arachidonyl trifluoromethylketone, a cPLA2 inhibitor; p-bromophenacylbromide, a sPLA2 inhibitor; or RHC80267, a diacylglycerol lipase inhibitor, led to a partial inhibition of the redirected lysis against P815 target cells as well the granule content release induced by NKR-P1A cross-linking. A complete abolishment of these events was observed when the cells were simultaneously incubated with all three inhibitors. Taken together, our results support a crucial role for the arachidonate-generating enzymes in the induction of lytic activity of NK cells directly or by leading to generation of additional mediators that can play a role in the context of NK cell activation and cytotoxic functions.

Animals↗
PubMed1990

Natural killer activity and antibody-dependent cellular cytotoxicity in progressive systemic sclerosis.

Enhanced natural killer (NK) activity and normal lymphocyte antibody-dependent cellular cytotoxicity (ADCC) were observed in 16 patients with a diagnosis of progressive systemic sclerosis (PSS). Higher NK activity levels were observed against NK-sensitive K562 target cells, while the NK-resistant P815, Daudi and Raji cell lines were not lysed. Cytofluorimetric studies and morphological analysis of peripheral blood lymphocytes (PBL) showed an increased number of CD16 positive cells and large granular lymphocytes (LGL), indicating that the enhancement observed was probably attributable to an increase in the number of circulating NK cells.

Adult↗
PubMed1989

Effects of cadmium on lymphocyte activation.

The effects of cadmium (Cd) on phytohemoagglutinin or phorbol myristate acetate-induced lymphocyte activation were investigated and a dose-dependent inhibition of cell proliferation was found. Kinetic studies revealed that the Cd-sensitive step is an early event of T cell stimulation. Failure of IL2 secretion and reduction of IL2 receptor expression in the Cd-treated cells are also reported. Regardless of which mechanism is responsible for Cd effects, our studies show that the inhibition of lymphocyte activation is associated with reduced [3H]phorbol dibutyrate binding to Ca2+-phospholipid-dependent protein kinase and altered breakdown of phosphatidylinositols. Thus, Cd interferes with two biochemical events which play a critical role in lymphocyte signal transduction and activation.

Adult↗
PubMedDate not supplied

Apoptosis induced by oxaliplatin in human colon cancer HCT15 cell line.

BACKGROUND: Oxaliplatin (L-OHP), active in a wide range of human and animal tumours, also CDDP-resistant, possesses unique molecular characteristics of action. However, the mechanisms by which the damage induced by L-OHP triggers a death signal are not yet fully defined. MATERIALS AND METHODS: After L-OHP treatment of the HCT15 human colon cancer cell line, apoptosis was evaluated by DNA laddering detection and by flow cytometry; the effect on specific caspase-3, -8 and -9 inhibitors, mitochondrial membrane permeability transition, cytochrome C release and expression of CD95 and CD95L were also assessed. RESULTS: HCT15 cells underwent apoptosis when treated with all used drug concentrations (7-25 microM). Treatment of cells with L-OHP resulted in the activation of caspase-8, -9 and -3, in a mitochondrial membrane depolarisation, and in an increase of CD95 receptor and CD95 ligand levels. CONCLUSION: The results correlated well with the ability of L-OHP to induce apoptosis and give further insights into the mechanisms underlying the L-OHP-induced apoptosis of tumor cells.

Adenocarcinoma↗