No abstract

To study the effects of [6]-gingerol, a ginger phytochemical, on tight junction (TJ) molecules, we investigated TJ tightening and signal transduction pathways in human pancreatic duct cell-derived cancer cell line PANC-1. The following methods were utilized: MTT assay to determine cytotoxicity; zymography to examine matrix metalloproteinase (MMP) activities; transepithelial electrical resistance (TER) and paracellular flux for TJ measurement; RT-PCR and immunoblotting for proteins related to TJ and invasion; and EMSA for NF-κB activity in PANC-1 cells. Results revealed that TER significantly increased and claudin 4 and MMP-9 decreased compared to those of the control. TJ protein levels, including zonula occludens (ZO-) 1, occludin, and E-cadherin, increased in [6]-gingerol-treated cells, which correlated with a decrease in paracellular flux and MMP activity. Furthermore, NF-κB/Snail nuclear translocation was suppressed via downregulation of the extracellular signal-regulated kinase (ERK) pathway in response to [6]-gingerol treatment. Moreover, treatment with U0126, an ERK inhibitor, completely blocked NF-κB activity. In conclusion, these findings demonstrate that [6]-gingerol regulates TJ-related proteins and suppresses invasion and metastasis through NF-κB/Snail inhibition via inhibition of the ERK pathway. Therefore, [6]-gingerol may suppress the invasive activity of PANC-1 cells.

β-lapachone is a naturally occurring quinone that selectively induces apoptotic cell death in a variety of human cancer cells in vitro and in vivo; however, its mechanism of action needs to be further elaborated. In this study, we investigated the effects of β-lapachone on the induction of apoptosis in human gastric carcinoma AGS cells. β-lapachone significantly inhibited cellular proliferation, and some typical apoptotic characteristics such as chromatin condensation and an increase in the population of sub-G1 hypodiploid cells were observed in β-lapachone-treated AGS cells. Treatment with β-lapachone caused mitochondrial transmembrane potential dissipation, stimulated the mitochondria-mediated intrinsic apoptotic pathway, as indicated by caspase-9 activation, cytochrome c release, Bcl-2 downregulation and Bax upregulation, as well as death receptor-mediated extrinsic apoptotic pathway, as indicated by activation of caspase-8 and truncation of Bid. This process was accompanied by activation of caspase-3 and concomitant with cleavage of poly(ADP-ribose) polymerase. The general caspase inhibitor, z-VAD-fmk, significantly abolished β-lapachone-induced cell death and inhibited growth. Further analysis demonstrated that the induction of apoptosis by β-lapachone was accompanied by inactivation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. The PI3K inhibitor LY29004 significantly increased β-lapachone-induced apoptosis and growth inhibition. Taken together, these findings indicate that the apoptotic activity of β-lapachone is probably regulated by a caspase-dependent cascade through activation of both intrinsic and extrinsic signaling pathways, and that inhibition of the PI3K/Akt signaling may contribute to β-lapachone-mediated AGS cell growth inhibition and apoptosis induction.

Excessive bone resorption by osteoclasts causes bone loss-related diseases and reactive oxygen species (ROS) act as second messengers in intercellular signaling pathways during osteoclast differentiation. In this study, we explored the protective effects of fermented oyster extract (FO) against receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclast differentiation in murine monocyte/macrophage RAW 264.7 cells. Our results showed that FO markedly inhibited RANKL-induced activation of tartrate-resistant acid phosphatase and formation of F-actin ring structure. Mechanistically, FO has been shown to down-regulate RANKL-induced expression of osteoclast-specific markers by blocking the nuclear translocation of NF-κB and the transcriptional activation of nuclear factor of activated T cells c1 (NFATc1) and c-Fos. Furthermore, FO markedly diminished ROS production by RANKL stimulation, which was associated with blocking the expression of nicotinamide adenine dinucleotide phosphate oxidase 1 (NOX1) and its regulatory subunit Rac-1. However, a small interfering RNA (siRNA) targeting NOX1 suppressed RANKL-induced expression of osteoclast-specific markers and production of ROS and attenuated osteoclast differentiation as in the FO treatment group. Collectively, our findings suggest that FO has anti-osteoclastogenic potential by inactivating the NF-κB-mediated NFATc1 and c-Fos signaling pathways and inhibiting ROS generation, followed by suppression of osteoclast-specific genes. Although further studies are needed to demonstrate efficacy in in vivo animal models, FO may be used as an effective alternative agent for the prevention and treatment of osteoclastogenic bone diseases.

beta-lapachone, a quinone compound obtained from the bark of the lapacho tree (Tabebuia avellanedae), was reported to have anti-inflammatory and anti-cancer activities. In this study, we investigated novel functions of beta-lapachone in terms of anti-metastasis and anti-invasion abilities using human hepatocarcinoma cell lines, HepG2 and Hep3B. beta-lapachone dose-dependently inhibited cell viability and migration of both HepG2 and Hep3B cells, as determined by methylthiazoletetrazolium (MTT) assay and wound healing assay. RT-PCR and Western blot data revealed that beta-lapachone dramatically increased the levels of protein, as well as mRNA expression of early growth response gene-1 (Egr-1) and throbospondin-1 (TSP-1) at an early point in time, and then decreased in a time-dependent manner. In addition, down-regulation of Snail and up-regulation of E-cadherin expression were observed in beta-lapachone-treated HepG2 and Hep3B cells, and this the associated with decreased invasive ability as measured by matrigel invasion assay. Taken together, our results strongly suggest that beta-lapachone may be expected to inhibit the progression and metastasis of hepatoma cells, at least in part by inhibiting the invasive ability of the cells via up-regulation of the expression of the Egr-1, TSP-1, and E-cadherin.

No abstract

To find out whether the immunohistochemical expression of neuropeptid Y (NPY) and leptin receptor (LR) in the rat hypothalamus is influenced by adlay seed water extract (adlay), obesity in rats was induced by high fat diet (HFD) for 8 weeks; these rats were injected with 50 mg/100 g body weight adlay daily for 4 weeks. The results showed that the optical density of NPY immunoreactivity in paraventricular nucleus of rats increased approximately by 3.4 fold in HFD group compared to the normal diet group. Conversely, that of HFD + adlay group was about 2.6 fold lower than HFD group. The pattern of LR expression was similar to that of NPY. Both of NPY and LR mRNA levels, determined by real time PCR, in HFD + adlay group were decreased compared to those of HFD group, but there were no significant changes in the level of LR. These results suggest that adlay may regulate neuroendocrine activity in the brain. Accordingly, administration of adlay may be considered for therapies targeting obesity.

Bupleurum falcatum L. is employed in oriental medicine in Korea. This root has been used for anti-inflammatory, anti-pyretic, and anti-hepatotoxic effects in the treatments of common cold, fever, and hepatitis. One of major bioactive compounds of Radix Bupleuri is the saikosaponin a (SSNa). However, little is known concerning the effects of SSNa on obesity associated with a state of low-grade inflammation. Consequently, this study was conducted to determine the inhibition of the inflammation pathway of SSNa in obesity. MTT assay was conducted for cytotoxicity and viability; nuclear and cytoplasmic fractions were extracted from adipocytes for translocation of nuclear factor-κB cells (NF-κB); nitric oxide (NO) production and secretion using Griess reagent; reverse transcription-polymerase chain reaction (RT-PCR) and immunoblotting for mRNA and protein levels associated with inflammation in the hypertrophied adipocytes. The results revealed that SSNa significantly decreased the expression of tumor necrosis factor-α (TNFα), interleukin (IL)-1β and IL-6 as proinflammatory cytokines, compared to that of non-treated control cells. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as inflammatory factors were reduced by treatment of these cells with SSNa and also suppressed NO production. Phosphorylation of IκBα was inhibited and translocation of NF-κB was suppressed via the ERK pathway in response to SSNa treatment. In conclusion, the results demonstrated that SSNa can inhibit the expression of inflammatory-associated genes in hypertrophied 3T3-L1 adipocytes and is a potent inhibitor of NF-κB activation. Thus these results suggest that SSNa is a novel therapeutic agent against that can be used against obesity-associated inflammation.