8-prenylnaringenin and Breast-Neoplasms

Postmenopausal women are increasingly using botanicals for menopausal symptom relief due to the increased breast cancer risk associated with traditional estrogen therapy. The deleterious effects of estrogens are associated with estrogen receptor (ER)α-dependent proliferation, while ERβ activation could enhance safety by opposing ERα effects. Three medicinal licorice species, Glycyrrhiza glabra ( G. glabra), G. uralensis, and G. inflata, were studied for their differential estrogenic efficacy. The data showed higher estrogenic potency for G. inflata in an alkaline phosphatase induction assay in Ishikawa cells (ERα) and an estrogen responsive element (ERE)-luciferase assay in MDA-MB-231/β41 breast cancer cells (ERβ). Bioassay-guided fractionation of G. inflata led to the isolation of 8-prenylapigenin (3). Surprisingly, a commercial batch of 3 was devoid of estrogenic activity. Quality control by MS and qNMR revealed an incorrect compound, 4'- O-methylbroussochalcone B (10), illustrating the importance of both structural and purity verification prior to any biological investigations. Authentic and pure 3 displayed 14-fold preferential ERβ agonist activity. Quantitative analyses revealed that 3 was 33 times more concentrated in G. inflata compared to the other medicinal licorice extracts. These data suggest that standardization of G. inflata to 3 might enhance the safety and efficacy of G. inflata supplements used for postmenopausal women's health.

Topics: Breast Neoplasms; Chalcones; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogens; Female; Flavones; Glycyrrhiza; Humans; Plant Extracts

Hops (Humulus lupulus L.) produce unique prenylflavonoids that exhibit interesting bioactivities. This study investigates the interactions between selected prenylflavonoids and breast cancer resistance protein (BCRP/ABCG2), an efflux transporter important for xenobiotic bioavailability and multidrug resistance (MDR).. ABCG2-inhibitory activity of xanthohumol (XN), isoxanthohumol (IX), 6-prenylnaringenin (6-PN), 8-prenylnaringenin (8-PN), and 6,8-diprenylnarigenin (6,8-diPN) was evaluated using mitoxantrone accumulation and vesicular transport assays. XN, IX, and 8-PN were tested for a substrate-type relationship with ABCG2 using ATPase and bidirectional transport assays. The prenylflavonoids exhibited significant ABCG2-inhibitory activities in mitoxantrone accumulation and vesicular transport assays. In the ATPase assay, XN, IX, and 8-PN inhibited baseline and sulfasalazine-stimulated ATPase activities with IC50 of 2.16-27.0 μM. IX and 8-PNalso displayed bell-shaped activation curves in Ko143-suppressed membranes, indicating a substrate-type relationship. For IX, efflux ratios of 1.25 ± 0.21 and 9.18 ± 0.56 were observed in wild type and ABCG2-overexpressing MDCKII cell monolayers, respectively. The latter was reduced to 1.25 ± 0.15 in the presence of the ABCG2-specific inhibitor Ko143, demonstrating an ABCG2-mediated efflux of IX. Additionally, evidence was shown for the involvement of ABCG2 in the efflux of 8-PN and/or its sulfate conjugate.. Prenylflavonoids are potent inhibitors of ABCG2 and therefore implicated in ABCG2-mediated food/herb-drug interactions and MDR. ABCG2-mediated efflux of prenylflavonoids may represent one mechanism that regulates prenylflavonoid bioavailability.

Topics: Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Biological Availability; Breast Neoplasms; Drug Resistance, Neoplasm; Female; Flavanones; Flavonoids; Gene Expression Regulation, Neoplastic; HEK293 Cells; Herb-Drug Interactions; Humans; Humulus; Membrane Transport Proteins; Mitoxantrone; Neoplasm Proteins; Phytoestrogens; Propiophenones; Xanthones; Xenobiotics

Xanthohumol (XN) and 8-prenylnaringenin (8PN) are hop (Humulus lupulus L.) polyphenols studied for their chemopreventive effects on certain cancer types. The breast cancer line MCF-7 was treated with doses ranging from 0.001 to 20 µM of XN or 8PN in order to assess the effects on cell viability and oxidative stress. Hoechst 33342 was used to measure cell viability and reactive oxygen species (ROS) production was determined by 2',7'-dichlorofluorescein diacetate. Catalase, superoxide dismutase, and glutathione reductase enzymatic activities were determined and protein expression of sirtuin1, sirtuin3, and oxidative phosphorylation system (OXPHOS) were done by Western blot. Treatments XN 0.01, 8PN 0.01, and 8PN 1 µM led to a decrease in ROS production along with an increase of OXPHOS and sirtuin expression; in contrast, XN 5 µM gave rise to an increase of ROS production accompanied by a decrease in OXPHOS and sirtuin expression. These results suggest that XN in low dose (0.01 µM) and 8PN at all assayed doses (0.001-20 µM) presumably improve mitochondrial function, whereas a high dose of XN (5 µM) worsens the functionality of this organelle.

Topics: Breast Neoplasms; Catalase; Cell Survival; Electron Transport Complex I; Female; Flavanones; Flavonoids; Gene Expression Regulation, Neoplastic; Glutathione Reductase; Humans; MCF-7 Cells; Mitochondria; Oxidative Stress; Propiophenones; Reactive Oxygen Species; Superoxide Dismutase

8-Prenylnaringenin (8PN), one of the strongest plant-derived oestrogen receptors (ERs) ligand, has been suggested to have potential cancer chemo-preventive activities and anti-angiogenic properties. Because published data suggest that ERs serve as nodal point that allows interactions between hormones and growth factors mediated pathways, we decided to investigate the effects exerted by 8PN on Epidermal growth factor (EGF)-elicited pathways in breast cancer cells. Here we show that in ER positive MCF-7 cells, 8PN interferes with EGF induced cell proliferation by strongly inhibiting activation of PI(3)K/Akt pathway, without affecting EGFR expression or tyrosine phosphorylation, and exerting a synergistic activation of Erk1/2 phosphorylation. Moreover, we demonstrate that 8PN is a direct inhibitor of PI(3)K activity as it is shown by in vitro experiments with the purified enzyme and by its inability to impair serine phosphorylation of a constitutive active form of Akt. These findings suggest that inhibition of PI(3)K is a novel mechanism which contributes to 8PN activity to inhibit cancer cell survival and EGF induced proliferation.

Topics: Breast Neoplasms; Cell Line, Tumor; Cyclin D1; Enzyme Activation; Epidermal Growth Factor; Extracellular Signal-Regulated MAP Kinases; Female; Flavanones; Humans; Molecular Structure; Phosphatidylinositol 3-Kinases; Phytoestrogens; Receptors, Estrogen; Signal Transduction

The activity of 8-prenylapigenin (8-PA) and its 3'-methoxylated analogue isocannflavin B (IsoB) was investigated in estrogen-dependent T47-D and estrogen-independent MDA-MB-231 human breast cancer cell lines. 8-PA showed a biphasic effect on T47-D cell proliferation, while no significant effect was observed on MDA-MB-231 cells. Conversely, IsoB exhibited only an inhibitory effect on T47-D cell proliferation, accompanied by the appearance of an intense intracytoplasmic vacuolization of autophagic origin. Moreover, biochemical analysis showed that IsoB reduced Akt phosphorylation and p21(Cip1) expression in T47-D cells. These data show that the prenylflavone moiety is a versatile platform for the induction and modulation of bioactivity.

Topics: Antineoplastic Agents, Phytogenic; Autophagy; Breast Neoplasms; Cannabis; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Cytoplasm; Dose-Response Relationship, Drug; Estrogens; Female; Flavanones; Flavones; Flavonoids; Humans; Humulus; Phosphorylation; Phytoestrogens; Phytotherapy; Plant Extracts; Prenylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Vacuoles

The estrogenic flavanone rac-8-prenylnaringenin (8-PN) and 3 derivatives (rac-7-(O-prenyl)naringenin-4'-acetate (7-O-PN), rac-5-(O-prenyl)naringenin-4',7-diacetate (5-O-PN), and rac-6-(1,1-dimethylallyl)naringenin (6-DMAN) were prepared by chemical synthesis and analyzed with respect to their toxicity and possible cell cycle effects in human acute myeloid leukemia (HL-60) cells. With the exception of 5-O-PN, all the other naringenins showed only weak toxic effects at concentrations below 50 micromol/l. A cell cycle analysis over several cell generations up to 4 days was carried out using the fluorescent dye carboxyfluorescein diacetate N-succinimidyl ester (CFSE) followed by propidium iodide (PI) staining at the end of the experiment. The well-studied flavonol quercetin was included in the analysis as a reference substance. All flavonoids affected cell proliferation, but the extent and the resulting changes in the proliferation pattern were specific for each substance. In contrast to the radical scavenging activity of quercetin, the tested flavanones showed no anti-oxidative properties using several different test systems. Similarly, the mitochondrial membrane potential (DeltaPsim) was hardly effected by these compounds, while both menadione and quercetin strongly reduced the potential after 1 h of treatment. The reported chemical modification of interesting lead substances (like the strongly estrogenic 8-PN) presents a promising approach to modulate the properties of a relevant substance in a pharmacologically desirable way. The low toxicity and weak cytostatic properties of the tested naringenin derivatives is encouraging for further studies on known naringenin target molecules.

Topics: Benzimidazoles; Breast Neoplasms; Carbocyanines; Cell Division; Cell Line, Tumor; Cell Membrane; Dose-Response Relationship, Drug; Flavanones; Fluorescent Dyes; Free Radical Scavengers; Germany, East; HL-60 Cells; Humans; Membrane Potentials; Mitochondria; Quercetin; Reactive Oxygen Species; Time Factors; Vitamin K 3

The E-cadherin/catenin complex is a powerful invasion suppressor in epithelial cells. It is expressed in the human MCF-7 breast cancer cell line family, but functionally defective in the invasive MCF-7/6 variant. Previous experiments have shown that IGF-I, tamoxifen, retinoic acid and tangeretin are able to upregulate the function of this complex in MCF-7/6 cells. We investigated the effect of 8-prenylnaringenin (8-PN), the phytoestrogen present in hops and beer, on aggregation, growth and invasion in MCF-7/6 cells. 8-PN was found to stimulate E-cadherin-dependent aggregation and growth of MCF-7/6 cells in suspension. These effects could be inhibited by the pure anti-estrogen ICI 182,780. 8-PN did not affect invasion of MCF-7/6 cells in the chick heart assay in vitro. In all these aspects 8-PN mimics the effects of 17beta-estradiol on MCF-7/6 cells.

Topics: Beer; Breast Neoplasms; Cadherins; Cell Adhesion; Cell Aggregation; Estrogens, Non-Steroidal; Female; Flavanones; Flavonoids; Humans; Humulus; Isoflavones; Phytoestrogens; Plant Preparations; Tumor Cells, Cultured; Tumor Stem Cell Assay; Up-Regulation