Cytotoxic activity of genistein-8-C-glucoside form Lupinus luteus L. and genistein against human SK-OV-3 ovarian carcinoma cell line.

Genistein belongs to isoflavones, which are a subclass of flavonoids, a large group of polyphenolic compounds widely distributed in plants. Numerous in vitro studies suggest that isoflavones, particularly genistein, have both chemopreventive and chemotherapeutic potential in multiple tumor types. However, the molecular and cellular mechanisms of genistein effects on human ovarian cancer cells are still little known. In the present study, we investigated anticancer activity of genistein and its natural glucoside, genistein-8-C-glucoside isolated from flowers of Lupinus luteus L. We examined the effects of the two isoflavones alone or in combination on cultured human SK-OV-3 ovarian carcinoma cells. The cells were exposed to genistein and genistein-8-C-glucoside at various concentrations (1-90 µM) for 24 and 48 h. The cytotoxic and apoptotic properties of compounds were studied by the colorimetric 3-[4,5-2-yl]-2-5-diphenyltetrazolium bromide assay and the acridine orange/ethidium bromide staining technique. The morphological features of SK-OV-3 cells were examined by Nomarski differential interference contrast combined with a confocal laser scanning microscope. The level of ROS was evaluated with fluorescence probes: dichlorofluorescein-diacetate by flow cytometry. Changes in mitochondrial membrane potential were determined using 5,5,6,6-tetrachloro-1,1,3,3-tetraethylbenzimidazolcarbocyanine iodide. Genistein-treatment and genistein-8-C-glucoside-treatment resulted in the inhibition of cell proliferation, induction of apoptotic cell death and loss of mitochondrial membrane potential. The present data provide the first evidence in vitro that genistein-8-C-glucoside and combination genistein-genistein-8-C-glucoside could be a potential chemotherapeutic candidate for ovarian cancer therapy.

How do the full-generation poly(amido)amine (PAMAM) dendrimers activate blood platelets? Platelet membrane zeta potential and other membrane-associated phenomena.

We explored the hypothesis that zeta potential altered by polycations affects blood platelet activation and reactivity, the phenomena associated with membrane lipid fluidity and platelet mitochondrial bioenergetics. PAMAM dendrimers generation- and dose-dependently enhanced zeta potential of platelets (from -10.7 mV to -4.3 mV). Increased expressions of activation markers, P-selectin and the active complex αIIbß3, as well as significantly enhanced fibrinogen binding occurred upon the in vitro incubation of blood platelets in the presence of PAMAMs G3 and G4 (resp. 62.1% and 69.4% vs. 1.4% and 2.7% in control for P-selectin, P<0.0001). PAMAM dendrimers increased fluidity of platelet membrane lipid bilayer, while they did not affect platelet mitochondria respiration. Increased platelet activation and their responses to agonists in vitro were statistically associated with the revealed alterations in zeta potential. Our results support the hypothesis that polycation-mediated "neutralized" zeta potential may underlie the activating effects of PAMAMs on blood platelets.

How do the full-generation poly(amido)amine (PAMAM) dendrimers activate blood platelets? Activation of circulating platelets and formation of "fibrinogen aggregates" in the presence of polycations.

Direct use of poly(amido)amine (PAMAM) dendrimers as drugs may be limited, due to uncertain (cyto)toxicity. Peripheral blood components, which constitute the first line of a contact with administered pharmaceuticals, may become vastly affected by PAMAM dendrimers. The aim of this study was to explore how PAMAMs' polycationicity might affect blood platelet activation and reactivity, and thus trigger various haemostatic events. We monitored blood platelet reactivity in rats with experimental diabetes upon a long-term administration of the unmodified PAMAM dendrimers. In parallel, the effects on blood flow in a systemic circulation was recorded intravitally in mice administered with PAMAM G2, G3 or G4. Compounding was the in vitro approach to monitor the impact of PAMAM dendrimers on blood platelet activation and reactivity and on selected haemostatic and protein conformation parameters. We demonstrated the activating effects of polycations on blood platelets. Some diversity of the revealed outcomes considerably depended on the used approach and the particular technique employed to monitor blood platelet function. We discovered undesirable impact of plain PAMAM dendrimers on primary haemostasis and their prothrombotic influence. We emphasize the need of a more profound verifying of all the promising findings collected for PAMAMs with the use of well-designed in vivo preclinical studies.