Nebrodeolysin, A Novel Hemolytic Protein From The Mushroom Pleurotus Nebrodensis With Cytostatic Activity Against Human Cancer Cell Lines And Anti-HIV-1 Activity

We have isolated and partially characterized a novel hemolysin (nebrodeolysin) from the edible mushroom Pleurotus nebrodensis, and our studies emphasize the anti-proliferative and antiviral activities of nebrodeolysin.A novel hemolysin was isolated from the edible mushroom Pleurotus nebrodensis, using ion exchange chromatography on CM-sepharose, DEAE-sepharose and gel filtration on sephacryl S-200. The hemolysin from Pleurotus nebrodensis hemolysin (nebrodeolysin), is a monomer protein with a molecular weight of approximately 27 kDa as demonstrated by gel filtration and SDS-PAGE, and with a pI of about 6.1.We tested the haemolytic activity of nebrodeolysin towards rabbit erythrocytes at 25°C for 30 min, and the concentration of nebrodeolysin for inducing 50% hemolysis were estimated to be 0.1μg/ml. At a concentration of 0.3μg/ml, approx.90% of the intracellular potassium ions leaked within 3 min after the addition of hemolysin, whereas onset of haemolysis occurred after a 5 min- or -longer incubation time under the same conditions. The failure to be inhibited from sugar is most likely due to the lack of recognition of specific carbohydrate configurations that are present on the glycoproteins of the cell envelopes. Comparatively, hemolysin could assemble into pore-forming complexes on the cell membrane. This mechanism of its interaction with the cell membrane may be leading to hemolysis erythrocytesThis hemolysin showed strong inhibition of the growth of human cancer cell lines, e.g. Lu-04 (66.6%±0.5), Bre-04 (98.4%±1.3) and HepG2 (97.9%±0.7) at 50μg/ml.To measure the inhibitory effect on the viral cytopathogenic effects (CPE) in cell culture, nebrodeolysin was exposed to different cell cultures that were infected by a variety of DNA and RNA viruses. However, none of the viruses were inhibited at subtoxic concentrations. Only the replication of HIV-1 (III_B) but not HIV-2 (ROD) was inhibited by nebrodolysin in CEM cell cultures at an EC50 of 65±41μg/ml, being non-toxic at 100μg/ml. This is the first report on a hemolysin from a mushroom with anti-HIV-1 activity. Our findings may have general implications in medicinal properties and therapeutic effects.