Hee Juhn Park

Kalopanaxsaponin A inhibits PMA-induced invasion by reducing matrix metalloproteinase-9 via PI3K/Akt- and PKCδ-mediated signaling in MCF-7 human breast cancer cells

Induction of matrix metalloproteinase (MMP)-9 is particularly important for the invasiveness of breast cancers. We investigated the inhibitory effect of kalopanaxsaponin A (KPS-A) on cell invasion and MMP-9 activation in phorbol 12-myristate 13-acetate (PMA)-treated MCF-7 human breast cancer cells. KPS-A inhibited PMA-induced cell proliferation and invasion. PMA-induced cell invasion was blocked in the presence of a primary antibody of MMP-9, and KPS-A suppressed the increased expression and/or secretion of MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1. Using specific inhibitors, we confirmed that PMA-induced cell invasion and MMP-9 expression is primarily regulated by nuclear factor-kappa B (NF-kappaB) activation via phosphatidylinositol 3-kinase (PI3K)/Akt and activator protein-1 (AP-1) activation via extracellular signal-regulated kinase (ERK)1/2. KPS-A decreased PMA-induced transcriptional activation of NF-kappaB and AP-1 and inhibited PMA-induced phosphorylation of ERK1/2 and Akt. Treatment with the protein kinase C (PKC)delta inhibitor rottlerin caused a marked decrease in PMA-induced MMP-9 secretion and cell invasion, as well as ERK/AP-1 activation, and KPS-A reduced PMA-induced membrane localization of PKCdelta. Furthermore, oral administration of KPS-A led to a substantial decrease in tumor volume and expression of proliferating cell nuclear antigen, MMP-9, TIMP-1 and PKCdelta in mice with MCF-7 breast cancer xenografts in the presence of 17beta-estradiol. These results suggest that KPS-A inhibits PMA-induced invasion by reducing MMP-9 activation, mainly via the PI3K/Akt/NF-kappaB and PKCdelta/ERK/AP-1 pathways in MCF-7 cells and blocks tumor growth and MMP-9-mediated invasiveness in mice with breast carcinoma. Therefore, KPS-A may be a promising anti-invasive agent with the advantage of oral dosing.

Hypoglycemic and hypolipidemic effects of tectorigenin and kaikasaponin III in the streptozotocin-induced diabetic rat and their antioxidant activityin vitro

Tectorigenin and kaikasaponin III from the flowers ofPueraria thunbergiana showed potent hypoglycemic and hypolipidemic effects in the streptozotocin-induced diabetic rats. Intraperitoneal administration of these two compounds with 5 and 10 mg/kg, respectively, for seven days to streptozotocin-induced rats significantly reduced the blood glucose, total cholesterol, LDL- and VLDL-cholesterol and triglyceride levels when compared with those of control group. Glycitein in which 5-OH is unlinked and tectoridin (7-O-glycoside of tectorigenin) isolated from the flowers ofP. thunbergiana did not improve hyperglycemia and hyperlipidemia. In addition, tectorigenin showedin vitro antioxidant effects on 1,1-diphenyl-2-pirylhydrazyl (DPPH) radical, xanthine-xanthine oxidase superoxide anion radical, and lipid peroxidation in rat microsomes induced by enzymatic and non-enzymatic methods. We further found that tectorigenin and kaikasaponin III protected the Vero cell line (normal monkey kidney) from injury by hydrogen peroxide. From these findings, it seems likely that the antioxidant action of tectorigenin and kaikasaponin III may alleviate the streptozotocin-induced toxicity and contribute to hypoglycemic and hypolipidemic effects.

Apoptosis-inducing Costunolide and a novel acyclic monoterpene from the stem bark ofMagnolia sieboldii

In a course of obtaining more amount of bioactive costunolide and successive phytochemical isolation fromMagnolia sieboldii (Magnoliaceae), a novel acyclic monoterpene 1 named deoxygeraniol (2,6(E)-dimethyl-2, 6-octadiene) was isolated along with β-sitosterol 3-O-linoleate (2), trilinolein (3) and high amount of costunolide (4) in the pure state. The structure of compound1 was determined on the basis of spectroscopic data. Costunolide was found to induce apoptotic cell death in a dose-dependent manner by nucleosomal DNA ladder and flow cytometric analysis. Immunoblot analysis showed that the level of the anti-apoptotic protein, Bcl-2, was decreased, whereas the cleavage of poly-(ADP-ribose) polymerase was activated. Furthermore, the N-acetyl-L-cysteine antioxidant effectively prevented costunolide-induced cytotoxicity. These results suggest that costunolide-induced cell death is mediated by reactive oxygen species Received March 20, 2001

Tectorigenin sensitizes paclitaxel-resistant human ovarian cancer cells through downregulation of the Akt and NFκB pathway

Paclitaxel (Taxol) is currently used as the front-line chemotherapeutic agent for several cancers including ovarian carcinoma; however, the drug frequently induces drug resistance through multiple mechanisms. The new strategy of using natural compounds in combination therapies is highly attractive because those compounds may enhance the efficacy of chemotherapy. In this study, we found that tectorigenin, an isoflavonoid isolated from flower of Pueraria thunbergiana, enhanced the growth-inhibitory effect of paclitaxel in paclitaxel-resistant ovarian cancer cells (MPSC1(TR), A2780(TR) and SKOV3(TR)) as well as their naive counterparts. The combination of tectorigenin with paclitaxel resulted in a synergistic apoptosis compared with either agent alone through activation of caspases-3, -8 and -9. Treatment with tectorigenin inhibited the nuclear translocation of NFκB and the expression of NFκB-dependent genes such as FLIP, XIAP, Bcl-2, Bcl-xL and COX-2, which are known to be associated with chemoresistance. In addition, the tectorigenin-paclitaxel combination inhibited the phosphorylation of IκB and IKK and the activation of Akt in paclitaxel-resistant cancer cells. Moreover, tectorigenin-paclitaxel-induced cell growth inhibition was enhanced by pretreatment with the Akt inhibitor LY294002 or overexpression of the dominant negative Akt (Akt-DN), but reduced by overexpression of constitutively activated Akt (Akt-Myr). Furthermore, we found that Akt-Myr, at least in part, reversed tectorigenin-paclitaxel-induced nuclear translocation of NFκB and the phosphorylation of IκB and IKK. These data suggest that tectorigenin could sensitize paclitaxel-resistant human ovarian cancer cells through inactivation of the Akt/IKK/IκB/NFκB signaling pathway, and promise a new intervention to chemosensitize paclitaxel-induced cytotoxicity in ovarian cancer.

Anti-Helicobacter pylori effect of costunolide isolated from the stem bark ofMagnolia sieboldii.

Helicobacter pylori (H. pylori) infection is now established as the major pathogenic factor in chronic gastritis and peptic ulcer disease. In addition, there is accumulating evidence thatH. pylori plays an important role in the process of gastric carcinogenesis. On the other hand, oriental traditional medicines have been used for stomach disease for thousands of years. In the present study, methanol extract from the stem bark ofMagnolia sieboldii (M. sieboldii) and its components were investigated on their inhibitory effects against urease activity and growth ofH. pylori in vitro. The methanol extract ofM. sieboldii significantly inhibited the growth ofH. pylori ATCC 43504 at 5 mg/ml. From the further fractionation, the chloroform fraction inhibited the bacterial growth dose-dependently. Among four fractions separated from the chloroform fraction by silica gel column chromatography, MS-C-2 was the most potent. Costunolide was isolated from the MS-C-2 subfraction by preparative TLC and recrystallization using n-hexane. Anti-H. pylori effect of costunolide was investigated using one commercial strain (H. pylori ATCC 43504) and three clinical strains (H. pylori 4, 43, 82548). Costunolide exhibited potent anti-H. pylori activity, and the MIC was around 100–200 μg/ml. However, costunolide had no inhibitory effect ofH. pylori urease activity at the concentration used for the growth inhibition assay. From these results, we conclude that costunolide inhibits the growth ofH. pylori by the independent manner ofH. pylori urease inhibition.

Structure of three new terpenoids, spiciformisins a andb, and monocyclosqualene, isolated from the herbs ofligularia fischeri var.spiciformis and cytotoxicity

The diethyletter fraction from the leaves extract ofLigularia fischeri var.spiciformis (Composi-tae) was subjected to silica gel column chromatography and yielded three new terpenoids named spiciformisin a (1), spiciformisinb (3), and monocyclosqualene (2). Acyclic diterpenes, spiciformisina and -b, were established as 3,7,11,15-tetramethyl-1,3(20)-hexadecadiene and 3,7,11,15-tetramethyl-1,3,6,10,14-hexadecapentaene (IUPAC), respectively. A monocyclic triterpene, monocyclosqualene, were determined as [3,8,12,16,16-pentamethyl-(3,7,11,15-hexa-decatetraenyl)]-3,3,5-trimethyl-1-cyclohexene. The structures were determined on the basis of NMR and MS analysis. Spiciformicin b showed potent cytotoxicity (IC50, <9.7 μg/ml against HL-60) in contrast to no cytotoxicity (IC50, >200 ng/ml against HL-60 cells) of spiciformicin a with acis-conjugated dienyl diexomethylene.

Buddlejasaponin IV induces cell cycle arrest at G2/M phase and apoptosis in immortalized human oral keratinocytes

Buddlejasaponin IV (BS‐IV), a major component of Pleurospermum kamtschaticum, exerts antiinflammatory and cytotoxic effects against cancer cells. The study investigated whether BS‐IV could prevent oral carcinogenesis by inhibiting the growth of immortalized human oral keratinocytes (IHOKs). BS‐IV reduced cell viability and induced cell cycle arrest at G2/M phase and apoptotic morphological changes in IHOKs. BS‐IV inhibited the levels of cyclin B1, Cdc2 and Cdc25C, but enhanced Chk2 phosphorylation. The increased levels of pRb and p21 protein and the activation of p53 were also noted in BS‐IV‐treated IHOKs. In addition, BS‐IV induced cytochrome c release from mitochondria by reducing antiapoptotic Bcl‐2 levels and increasing pro‐apoptotic Bax levels. BS‐IV treatment resulted in the activation of caspase‐9 and caspase‐3. PARP cleavage was also clearly observed in the BS‐IV‐treated IHOKs. Furthermore, the expression of the Fas death receptor and Fas ligand was induced and procaspase‐8 level was suppressed by BS‐IV treatment. Taken together, BS‐IV treatment inhibited the growth of IHOK cells via the induction of p53‐dependent cell cycle arrest at the G2/M phase and apoptosis via both mitochondrial‐dependent and death receptor‐mediated pathways. Thus, BS‐IV can be considered an excellent candidate for a chemopreventive agent to block the progression of HPV‐induced oral carcinogenesis. Copyright

Pleurospermum kamtschaticum Extract Induces Apoptosis via Mitochondrial Pathway and NAG-1 Expression in Colon Cancer Cells

To evaluate the anticarcinogenic activity of methanol extract of Pleurospermum kamtschaticum (PKE), we assessed its apoptosis-inducing capability in HT-29 colon carcinoma cells. PKE treatment for 2 h reduced cell viability in a dose-related manner, and induced apoptotic morphological changes. Flow cytometric analysis indicated that PKE treatment at 0.05 mg/ml induced early apoptosis in 66.2% of HT-29 cells. Additionally, Bcl-2 expression was substantially reduced in PKE-treated HT-29 cells, increasing the Bax/Bcl-2 ratio. The protein levels of procaspase-9 and procaspase-3 were decreased markedly, reflecting caspase-9 and caspase-3 activation, and resulting PARP cleavage was noted in the PKE-treated HT-29 cells. Furthermore, we detected increased NAG-1 expression in the PKE-treated HT-29 cells. In an in vivo study, intraperitoneal PKE administration suppressed the formation of tumor nodules in the lungs of mice. These results indicate that PKE can serve as a beneficial supplement in the treatment and the prevention of colon cancer.