Biomedical subjects

Daniela Vismara

Publications and source records attributed to Daniela Vismara.

3 recordsLinked to original sources

PubMed2006

Decrease of polyamine levels and enhancement of transglutaminase activity in selective reduction of B16-F10 melanoma cell proliferation induced by atrial natriuretic peptide.

The atrial natriuretic peptide (ANP) at physiological levels reduced the proliferation of highly metastatic murine (B16-F10) and human (SK-MEL 110) melanoma cell lines whereas rat aortic smooth muscle (RASM) cells were unaffected. In RASM cells, the levels of proliferation markers (putrescine, spermidine and spermine) increase after 24 h of epidermal growth factor (EGF) stimulation (RASM-EGF), but strongly decrease after 24 h of exposition to ANP. The B16-F10 cell line, which received no EGF stimulation, showed a similar decrease in polyamine content after ANP treatment. Furthermore, the enzymatic activity of a differentiation marker (transglutaminase) was increased for both RASM-EGF and B16-F10 cells after 24 h of treatment with 10(-10) mol/l ANP, concomitantly with the observed inhibition of polyamine biosynthesis and cell growth. Data obtained on B16-F10 cells treated with 8Br-GMPc or with an ANP analogue (cANF) support the involvement of the type C ANP receptor (NRP-C) in hormone effects. From the overall results, it appears that ANP may play a role in the inhibition of cellular growth under hyperproliferative conditions, as shown for RASM-EGF cells. The B16-F10 melanoma cell line showed similar results, but in the absence of mitogen stimulation. This observation suggests that the constitutive hyperproliferative state of tumor cells may be a sufficient condition to favor the ANP inhibitory effects on cell growth. This finding is particularly interesting in the light of a possible use of ANP as a potential selective antineoplastic agent.

Animals↗

PubMed2005

Atrial natriuretic peptide effects on intracellular pH changes and ROS production in HEPG2 cells: role of p38 MAPK and phospholipase D.

AIMS: The present study was performed to evaluate Atrial Natriuretic Peptide (ANP) effects on intracellular pH, phospholipase D and ROS production and the possible relationship among them in HepG2 cells. Cancer extracellular microenvironment is more acidic than normal tissues and the activation of NHE-1, the only system able to regulate pHi homeostasis in this condition, can represent an important event in cell proliferation and malignant transformation. METHODS: The ANP effects on pHi were evaluated by fluorescence spectrometry. The effects on p38 MAPK and ROS production were evaluated by immunoblots and analysis of DCF-DA fluorescence, respectively. RT-PCR analysis and Western blotting were used to determine the ANP effect on mRNA NHE-1 expression and protein levels. PLD-catalyzed conversion of phosphatidylcholine to phosphatydilethanol (PetOH), in the presence of ethanol, was monitored by thin layer chromatography. RESULTS: A significant pHi decrease was observed in ANP-treated HepG2 cells and this effect was paralleled by the enhancement of PLD activity and ROS production. The ANP effect on pHi was coupled to an increased p38 MAPK phosphorylation and a down-regulation of mRNA NHE-1 expression and protein levels. Moreover, the relationship between PLD and ROS production was demonstrated by calphostin-c, a potent inhibitor of PLD. At the same time, all assessed ANP-effects were mediated by NPR-C receptors. CONCLUSION: Our results indicate that ANP recruits a signal pathway associated with p38 MAPK, NHE-1 and PLD responsible for ROS production, suggesting a possible role for ANP as novel modulator of ROS generation in HepG2 cells.

Atrial Natriuretic Factor↗

PubMed2004

Expression of 60 kDa heat shock protein (Hsp60) on plasma membrane of Daudi cells.

In Daudi cells, a fraction of the 60 kDa heat shock protein (Hsp60), which is typically a mitochondrial protein, is located on cell membrane. This was demonstrated by the recovery of biotinylated Hsp60 in the anti-Hsp60 immunoprecipitate obtained from cells in which surface-exposed proteins were selectively labeled with biotin. In further experiments, isolated membrane proteins (obtained by two different biochemical methods) were probed in Western blot with two antibodies (N-20 and K-19) directed against different epitopes located, respectively, at the amino- and at the carboxyl-terminus of the Hsp60. Both these antibodies recognized, among the isolated membrane proteins, a unique band with an electrophoretic mobility identical to that of the cytoplasmic Hsp60, thus demonstrating that Hsp60 is present on cell surface as an intact, full-length, protein. FACS analysis, performed with the same two highly specific anti-Hsp60 antibodies, confirmed that both the N-terminus and the C-terminus of the Hsp60 are exposed outside the cell and are accessible for recognition by the corresponding antibody. Moreover, quantitative analysis of the data showed that constitutive cell surface expression of the Hsp60 is limited to a small fraction (about 10%) of the whole cell population.

Antibodies, Monoclonal↗