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Biomedical subjects

E Melloni

Publications and source records attributed to E Melloni.

207 records · Page 12Linked to original sources
PubMedDate not supplied

Effect of hyperthermia on rhodamine 123 cytotoxicity in doxorubicin-sensitive and doxorubicin-resistant human breast carcinoma cell lines in vitro.

Rhodamine 123 (Rh123) cytotoxicity and intracellular accumulation were studied in normothermic and hyperthermic conditions in a human breast carcinoma cell line (MCF7/WT) and its doxorubicin-resistant subline (MCF7/DoxR). MCF7/DoxR cells were resistant to hyperthermia and Rh123. Hyperthermic potentiation of Rh123 cytotoxicity was present in MCF7/WT but not in MCF7/DoxR cells. Results suggest that the effect observed in MCF7/WT cells is related to a heat-induced increased accumulation of Rh123 and not to a heat-induced activation of the drug. A low basal uptake and a fast release of Rh123 could explain the resistance of MCF7/DoxR to the drug. Resistance to Rh123 and lack of a heat-induced increased uptake account for the lack of hyperthermic enhancement of Rh123 cytotoxicity in the resistant cells.

Biological Transport, Active↗
PubMedDate not supplied

Participation of protein kinase C in the activation of human neutrophils by phorbol ester.

The calmodulin antagonist N(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7) has been examined as an inhibitor of superoxide anion production and granule exocytosis in phorbol ester (PMA)-activated neutrophils. Inhibition of the respiratory burst was observed at a concentration of W-7 identical to that required for inhibition of native protein kinase C (PKC), whereas the concentration required to inhibit the secretory response was found to correspond to that required for inhibition of the proteolytically converted fully active PKC. The IC50 of W-7 was in both cases 5 and 12 fold higher than that required for inhibition of calmodulin dependent kinases. The results confirm the essential role for the membrane-bound PKC in the production of O2- radicals and provide a clear evidence of the direct participation of the proteolytically activated cytosolic PKC to the secretory response of PMA activated neutrophils.

Cytoplasmic Granules↗
PubMedDate not supplied

Anti-PKC activity of some 3-(dialkylamino)-1H-naphtho [2,1-B] pyran-1-ones.

Some 3-(dialkylamino)-1H-naphtho [2,1-b] pyran-1-ones were tested to evaluate their ability to inhibit Protein Kinase C (PKC) activation. The model consisted in the detection of the superoxide anion in activated neutrophils. Naphthopyrans carrying 3-(diethylamino), 3-(1-piperidinyl) and 3-[bis(2-methoxyethyl)amino] groups emerged as the most active ones. Introduction of alkoxy groups in position 8 and 9 and of bromo substituent in position 8 on the naphthalene moiety was associated with an increase in anti-PKC activity. No activity was found when an electron withdrawing group was placed in position 2 of the 3-(dialkylamino)-1H-naphtho [2,1-b] pyran-1-ones.

Enzyme Inhibitors↗