xanthohumol and Carcinoma--Hepatocellular

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Hepatocellular; Cell Cycle; Cell Proliferation; Colonic Neoplasms; Flavonoids; HCT116 Cells; Hep G2 Cells; HT29 Cells; Humans; Liver Neoplasms; Propiophenones

Despite improvement in therapeutic strategies, median survival in advanced hepatocellular carcinoma (HCC) remains less than one year. Therefore, molecularly targeted compounds with less toxic profiles are needed. Xanthohumol (XN), a prenylated chalcone has been shown to have anti-proliferative effects in various cancers types in vitro. XN treatment in healthy mice and humans yielded favorable pharmacokinetics and bioavailability. Therefore, we determined to study the effects of XN and understand the mechanism of its action in HCC. The effects of XN on a panel of HCC cell lines were assessed for cell viability, colony forming ability, and cellular proliferation. Cell lysates were analyzed for pro-apoptotic (c-PARP and cleaved caspase-3) and anti-apoptotic markers (survivin, cyclin D1, and Mcl-1). XN concentrations of 5 μM and above significantly reduced the cell viability, colony forming ability and also confluency of all four HCC cell lines studied. Furthermore, growth suppression due to apoptosis was evidenced by increased expression of pro-apoptotic and reduced expression of anti-apoptotic proteins. Importantly, XN treatment inhibited the Notch signaling pathway as evidenced by the decrease in the expression of Notch1 and HES-1 proteins. Ectopic expression of Notch1 in HCC cells reverses the anti-proliferative effect of XN as evidenced by reduced growth suppression compared to control. Taken together these results suggested that XN mediated growth suppression is appeared to be mediated by the inhibition of the Notch signaling pathway. Therefore, our findings warrants further studies on XN as a potential agent for the treatment for HCC.

Topics: Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cell Survival; Flavonoids; Humans; Liver Neoplasms; Propiophenones; Receptors, Notch; Signal Transduction; Tumor Stem Cell Assay

Xanthohumol (XN) is the major prenylated chalcone of hops and hence an ingredient of beer. Despite many advances in understanding of the pharmacology of XN, one largely unresolved issue is its low bioavailability in the human organism. Also, not much is known about its actual concentrations and pharmacokinetics in liver and intestinal cells. Therefore, the uptake, intracellular distribution, and kinetics of XN were studied in various cell types, namely, hepatocellular carcinoma cells (HuH-7), hepatic stellate cells (HSC), primary cultured hepatocytes, and colorectal adenocarcinoma cells (Caco-2). Fluorescent microscopy allowed for the first time visualization and tracing of the uptake and intracellular distribution of XN. A rapid accumulation of XN concentrations that were up to >60-fold higher than the concentration present in the ambient culture medium was observed. Fluorescence recovery after photobleaching experiments revealed that most XN molecules are bound to cellular proteins, which may alter properties of cellular factors.

Topics: Biological Availability; Caco-2 Cells; Carcinoma, Hepatocellular; Cell Line, Tumor; Cells, Cultured; Flavonoids; Hepatic Stellate Cells; Hepatocytes; Humans; Humulus; Intestinal Mucosa; Kinetics; Liver Neoplasms; Propiophenones

Xanthohumol, the major prenylated chalcone found in hops, is well known to exert anti-cancer effects, but information regarding the impact on hepatocellular carcinoma (HCC) cells and potential adverse effects on non-tumorous hepatocytes is limited. Here, we show that xanthohumol at a concentration of 25 microM induced apoptosis in two HCC cell lines (HepG2 and Huh7). Furthermore, xanthohumol repressed proliferation and migration, as well as TNF induced NF-kappaB activity and interleukin-8 expression in both cell lines at even lower concentrations. In contrast, xanthohumol concentrations up to 100 microM did not affect viability of primary human hepatocytes in vitro. In summary, our data showed that xanthohumol can ameliorate different pro-tumorigenic mechanisms known to promote HCC progression, indicating its potential as promising therapeutic agent that selectively affects cancer cells.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Hepatocellular; Cell Movement; Cell Proliferation; Cell Survival; Flavonoids; Humans; Humulus; Interleukin-8; Liver Neoplasms; Propiophenones; Reverse Transcriptase Polymerase Chain Reaction

Xanthohumol is one of the main flavonoids in hop extracts and in beer. Very few investigations of xanthohumol have studied hepatocellular carcinoma. In this study, the inhibitory effects of xanthohumol on human hepatocellular carcinoma cell lines were investigated. The IC(50) values of xanthohumol for two hepatocellular carcinoma cell lines and one normal hepatocyte cell line were 108, 166 and 211 microm, respectively. Normal murine hepatocyte cell line had more resistance to xanthohumol than hepatocellular carcinoma cell lines. Besides, the inhibitory effects of xanthohumol on human hepatocellular carcinoma cell lines were attributed to apoptosis as indicated in the results of flow cytometry, fluorescent nuclear staining and electrophoresis of oligonucleosomal DNA fragments. Hop xanthohumol was more efficient in the growth inhibition of hepatocellular carcinoma cell lines than the flavonoids silibinin and naringin from thistle and citrus. It was shown for the first time that xanthohumol from hops effectively inhibits proliferation of human hepatocellular carcinoma cells in vitro.

Topics: Analysis of Variance; Animals; Apoptosis; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA Fragmentation; Flavanones; Flavonoids; Humans; Humulus; Mice; Phytotherapy; Plant Extracts; Propiophenones; Silybin; Silymarin

Xanthohumol is the major prenylated flavonoid present in the hop plant Humulus lupulus L. (Cannabinaceae) and a common ingredient of beer. Recently, xanthohumol has gained considerable interest due to its potential cancer chemo-preventive effect. The aim of this study was to reveal the possible anti-genotoxic activity of xanthohumol in metabolically competent human hepatoma HepG2 cells, by use of the comet assay. Xanthohumol by itself was neither cytotoxic nor genotoxic to the cells at concentrations below 10microM. However, a significant protective effect against the pro-carcinogens benzo(a)pyrene (BaP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) was observed at concentrations as low as 0.01microM. In cells treated with xanthohumol in combination with tert-butyl hydroperoxide (t-BOOH) - an inducer of reactive oxygen species (ROS) - no protective effect was observed and xanthohumol also showed no significant scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. On the other hand, HepG2 cells pre-treated with xanthohumol showed significantly reduced levels of t-BOOH-induced DNA strand breaks, indicating that its protective effect is mediated by induction of cellular defence mechanisms against oxidative stress. As xanthohumol is known to be an effective inhibitor of cytochrome P450 enzymes and an inducer of NAD(P)H: quinone reductase (QR), our findings can be explained by an inhibition of metabolic activation of pro-carcinogens and/or by induction of carcinogen-detoxifying and anti-oxidative enzymes by xanthohumol. These results provide evidence that xanthohumol displays anti-genotoxic activity in metabolically competent human cells.

Topics: Antimutagenic Agents; Benzo(a)pyrene; Carcinoma, Hepatocellular; Comet Assay; Cytoprotection; DNA Damage; Flavonoids; Humans; Liver Neoplasms; Mutagens; Propiophenones; Quinolines; Reactive Oxygen Species; tert-Butylhydroperoxide; Tumor Cells, Cultured