Interleukin 6 secretion from alternatively activated macrophages promotes the migration of endometriotic epithelial cells.

Accumulating evidence has suggested an interaction between endometriotic cells and macrophages in the endometriotic microenvironment and the potential role of this interaction in the pathogenesis of endometriosis. However, how endometriotic cells communicate with macrophages to influence their function is poorly understood. In the present study, we found that the mRNA expression and production of CC chemokine ligand 2 (CCL2) were much higher in human endometriotic epithelial cells (11Z and 12Z) than those in human endometrial epithelial cells (HES). The inhibition of CCL2 action using neutralizing antibodies substantially suppressed macrophage migration induced by endometriotic epithelial cells. The endometriosis-associated macrophages (EAMs), which are the macrophages that are stimulated by the conditioned medium (CM) of human endometriotic cells, highly expressed the M2 phenotype markers (MRC1 and TREM2). In addition, the CM of EAMs significantly increased cell migration in 12Z cells, but no significant change was observed in cell growth. RT-PCR and antibody array analyses revealed that EAMs highly express and produce interleukin (IL) 6 compared to macrophages stimulated by the CM of HES cells. Moreover, the EAM-CM-induced migration and MMP2/9 expression in endometriotic cells were significantly attenuated by IL6 signaling inhibition. These results suggest a reciprocal activation of macrophages and endometriotic cells via the soluble factors CCL2 and IL6, which may contribute to the development of endometriosis.

Brown algae phlorotannins enhance the tumoricidal effect of cisplatin and ameliorate cisplatin nephrotoxicity.

OBJECTIVE: The clinical application of cisplatin is limited due to its drug resistance and side effects. We investigated the effect of a phlorotannin-rich extract from the edible brown alga Ecklonia cava (PREC) and its major phlorotannin (dieckol) on cisplatin responsiveness and side effects. METHODS: The A2780 and SKOV3 ovarian cancer cell lines and the SKOV3-bearing mouse model were used. The MTT assay was applied to assess cell viability, and the annexin V assay was employed for apoptosis analysis. Reactive oxygen species (ROS) production and protein expression were assessed by H2DCFDA staining and Western blotting, respectively. RESULTS: We found that PREC enhanced the tumor growth-inhibitory effect of cisplatin and diminished cisplatin-induced nephrotoxicity and weight loss in SKOV3-bearing mice. PREC augmented cisplatin-induced apoptosis by activating caspases in SKOV3 and A2780 ovarian cancer cells. In addition, a combination of PREC and cisplatin-induced ovarian cancer cell apoptosis by downregulating the Akt and NFκB pathways. We further demonstrated that PREC increased intracellular ROS and that antioxidants significantly attenuated Akt-NFκB activation and apoptosis in ovarian cancer cells. In contrast, PREC inhibited cisplatin-induced ROS production and cell death in normal HEK293 kidney cells. Dieckol, a major compound in PREC, significantly enhanced the inhibition of tumor growth by cisplatin with less weight loss and kidney damage in a mouse model. CONCLUSION: These data suggest that brown algae phlorotannins may improve the efficacy of platinum drugs for ovarian cancer by enhancing cancer cell apoptosis via the ROS/Akt/NFκB pathway and reduce nephrotoxicity by protecting against normal kidney cell damage.

Leptin receptor is induced in endometriosis and leptin stimulates the growth of endometriotic epithelial cells through the JAK2/STAT3 and ERK pathways.

Leptin acts as a potential growth stimulator in several normal and neoplastic cells. Recent studies have shown the presence of increased levels of leptin in the peritoneal fluid of patients with endometriosis, implicating leptin in the pathogenesis of endometriosis. However, the specific function of leptin in the induction of mitogenesis in endometriosis is not known. This study investigated the expression of the leptin receptor (ObR) in endometrioma tissues and immortalized endometriotic cells, and the effect of leptin on cell growth. ObR expression was higher in endometriomas than in the normal endometrium, and it was detected in 74% of epithelial and 30% of stromal endometrioma tissues. In addition, human endometriotic epithelial cells (11Z and 12Z) showed a high level of ObR when compared with endometrial cells and endometriotic stromal cells (22B). Furthermore, leptin treatment stimulated the growth of 11Z and 12Z cells, but not that of 22B cells. Knockdown of the ObR in 11Z and 12Z cells impaired the ability of leptin to induce cell growth. Leptin induced the activation of Janus Kinases 2 (JAK2), signal transducers and activators of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK) in endometriotic epithelial cells. Moreover, pretreatment with the JAK2/STAT3 inhibitor AG490 and the ERK inhibitor PD98059 significantly inhibited leptin-induced cell growth. The present results show that the ObR is induced in endometriosis, and that leptin stimulates the growth of endometriotic epithelial cells through the JAK2/STAT3 and ERK pathways.

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.

CCL2 overexpression is associated with paclitaxel resistance in ovarian cancer cells via autocrine signaling and macrophage recruitment.

Tumor cells can secret various cytokines and chemokines, which affect the tumor cells themselves and the neighboring cells. Here, we observed that human ovarian cancer (OC) cells developed resistance to paclitaxel treatment following culture with the conditioned medium (CM) derived from paclitaxel-resistant OC (OCTR) cells. A cytokine array revealed that both OCTR cells secreted large amounts of CC chemokine ligand 2 (CCL2). CCL2 and its receptor, CCR2, were overexpressed in OCTR cells. CCL2 expression was associated with worse progression-free survival in patients with ovarian cancer. The inhibition of the CCL2/CCR2 axis suppressed the chemoresistance induced by OCTR-CM. The enhanced expression and production of CCL2 in OC cells were mediated via the NF-κB pathway, and stimulated the activation of the PI3K/Akt pathway, which resulted in the development of paclitaxel resistance in OC cells. Additionally, the OCTR cells significantly increased the migration of macrophages, which was also associated with the overproduction of CCL2 in chemoresistant cancer cells. The macrophages stimulated by OCTR cells expressed high levels of markers of M2 phenotype, and their CM significantly decreased the paclitaxel responsiveness of OC cells. The administration of a CCR2 inhibitor to a murine model significantly improved the paclitaxel sensitivity. These data suggested that apart from inducing chemoresistance in OC cells by acting as an autocrine factor, CCL2 also functions as a chemokine that induces the chemotaxis of macrophages, which may contribute to chemoresistance. Therefore, targeting the CCL2/CCR2 signaling axis may improve the therapeutic response of patients with ovarian cancer to paclitaxel.

Costunolide induces apoptosis in platinum-resistant human ovarian cancer cells by generating reactive oxygen species.

OBJECTIVE: The acquired resistance to platinum-based drugs has become an obstacle in the management of ovarian cancer. We investigated the apoptosis-inducing effect of costunolide, a natural sesquiterpene lactone, in platinum-resistant human ovarian cancer cells, along with the molecular mechanism of action. METHODS: Costunolide and cisplatin were examined in platinum-resistant human ovarian cancer cells. MTT assay for cell viability, PI staining for cell cycle profiling, and Annexin V assay for apoptosis analysis. ROS production and protein expression was assessed by H(2)DCFDA staining and Western blotting, respectively. Combination effect was determined using the Combination Index (CI) method. RESULTS: It was found that costunolide is more potent than cisplatin in inhibiting cell growth in three platinum-resistant ovarian cancer cell lines (MPSC1(PT), A2780(PT), and SKOV3(PT)). Costunolide induced apoptosis of platinum-resistant cells in a time- and dose-dependent manner and suppressed tumor growth in SKOV3(PT)-bearing mouse model. In addition, costunolide triggered the activation of caspase-3, -8, and -9. Pretreatment with caspase inhibitors neutralized the pro-apoptotic activity of costunolide. We further demonstrated that costunolide induced a significant increase in intracellular reactive oxygen species (ROS). Additionally, the antioxidant N-acetyl-L-cysteine (NAC) significantly attenuated the costunolide-induced production of ROS, activation of caspases, down-regulation of Bcl-2, and apoptosis in platinum-resistant ovarian cancer cells. Moreover, costunolide synergized with cisplatin to induce cell death in platinum-resistant ovarian cancer cells. CONCLUSIONS: Taken together, these data suggest that costunolide, alone or in combination with cisplatin, may be of therapeutic potential in platinum-resistant ovarian cancer.

Costunolide induces apoptosis in human endometriotic cells through inhibition of the prosurvival Akt and nuclear factor kappa B signaling pathway.

Endometriosis, a disease affecting 5-15% of women of reproductive age, is characterized by the ectopic growth of endometrial tissue. Costunolide, a sesquiterpene lactone, has anti-proliferative and pro-apoptotic activities that may be efficacious in therapy for endometriosis. In the present study, we investigated the effect of costunolide on the cell growth and apoptosis of endometriotic cells. We found that costunolide significantly inhibited the cell viability of 11Z and 12Z human endometriotic epithelial cells. Interestingly, endometriotic cells were more sensitive to costunolide treatment than immortalized endometrial cells (HES). Costunolide induced apoptosis of 11Z cells in a time-dependent manner as shown by accumulation of sub-G1 population. In addition, treatment with costunolide induced the activation of caspase-3, -8, and -9 in a dose- and time-dependent manner. Pretreatment with the broad caspase inhibitor z-VAD-fmk significantly reversed the costunolide-induced inhibition of cell viability in 11Z cells. We further demonstrated that costunolide inhibited the activation of Akt and nuclear factor kappa B (NFκB) and the expression of anti-apoptotic factors B-cell lymphoma-extra lage (Bcl-xL) and X-linked inhibitor of apoptosis protein (XIAP) in 11Z cells. These results suggest that costunolide induces apoptosis in human endometriotic epithelial cells by inhibiting the prosurvival NFκB and Akt pathway, leading to the downregulation of anti-apoptotic protein Bcl-xL and XIAP and the activation of caspases.

Protective Effect of Brown Alga Phlorotannins against Hyper-inflammatory Responses in Lipopolysaccharide-Induced Sepsis Models.

Brown algae have been recognized as a food ingredient and health food supplement in Japan and Korea, and phlorotannins are unique marine phenol compounds produced exclusively by brown algae. Sepsis is a whole-body inflammatory condition with a mortality rate of 30-40%. Here, we investigated the effects of a phlorotannin-rich extract of the edible brown alga Ecklonia cava against hyper-inflammatory response in LPS-induced septic shock mouse model. E. cava extract significantly increased the survival rate and attenuated liver and kidney damage in the mice. In addition, E. cava attenuated serum levels of NO, PGE2, and HMGB-1. In macrophages, treatment with E. cava extract down-regulated iNOS, COX-2, TNF-α, IL-6, and HMGB-1. In addition, E. cava suppressed the NIK/TAK1/IKK/IκB/NFκB pathway. Moreover, E. cava increased Nrf2 and HO-1 expression. HO-1 knockdown using siRNA restored the extract-suppressed NO and PGE2 production. Dieckol, a major compound in the extract, reduced mortality, tissue toxicity, and serum levels of the inflammatory factors in septic mice. These data suggest that brown algae phlorotannins suppress septic shock through negative regulation of pro-inflammatory factors via the NIK/TAK1/IKK/IκB/NFκB and Nrf2/HO-1 pathways.

Dieckol, isolated from the edible brown algae Ecklonia cava, induces apoptosis of ovarian cancer cells and inhibits tumor xenograft growth.

PURPOSE: Ecklonia cava is an abundant brown alga and has been reported to possess various bioactive compounds having anti-inflammatory effect. However, the anticancer effects of dieckol, a major active compound in E. cava, are poorly understood. In the present study, we investigated the anti-tumor activity of dieckol and its molecular mechanism in ovarian cancer cells and in a xenograft mouse model . METHODS: MTT assay, PI staining, and PI and Annexin double staining were performed to study cell cytotoxicity, cell cycle distribution, and apoptosis. We also investigated reactive oxygen species (ROS) production and protein expression using flow cytometry and Western blot analysis, respectively. Anti-tumor effects of dieckol were evaluated in SKOV3 tumor xenograft model. RESULTS: We found that the E. cava extract and its phlorotannins have cytotoxic effects on A2780 and SKOV3 ovarian cancer cells. Dieckol induced the apoptosis of SKOV3 cells and suppressed tumor growth without any significant adverse effect in the SKOV3-bearing mouse model. Dieckol triggered the activation of caspase-8, caspase-9, and caspase-3, and pretreatment with caspase inhibitors neutralized the pro-apoptotic activity of dieckol. Furthermore, treatment with dieckol caused mitochondrial dysfunction and suppressed the levels of anti-apoptotic proteins. We further demonstrated that dieckol induced an increase in intracellular ROS, and the antioxidant N-acetyl-L-cysteine (NAC) significantly reversed the caspase activation, cytochrome c release, Bcl-2 downregulation, and apoptosis that were caused by dieckol. Moreover, dieckol inhibited the activity of AKT and p38, and overexpression of AKT and p38, at least in part, reversed dieckol-induced apoptosis in SKOV3 cells. CONCLUSION: These data suggest that dieckol suppresses ovarian cancer cell growth by inducing caspase-dependent apoptosis via ROS production and the regulation of AKT and p38 signaling.

α-Terthienylmethanol, isolated from Eclipta prostrata, induces apoptosis by generating reactive oxygen species via NADPH oxidase in human endometrial cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Eclipta prostrate L. (syn. E. alba Hassk), commonly known as False Daisy, has been used in traditional medicine in Asia to treat a variety of diseases, including cancer. Although an anti-tumor effect has been suggested for E. prostrata, the exact anti-tumor effects and underlying molecular mechanisms of its bioactive compounds are poorly understood. The aim of this study was to identify compounds with anti-cancer activity from E. prostrata and to investigate their mechanism of action. MATERIALS AND METHODS: To assess cell viability, cell cycle progression, and apoptosis, we performed MTT assays and FACS analysis using Annexin and PI staining. We also investigated reactive oxygen species (ROS) production and caspase activation using flow cytometry and Western blot analysis, respectively. Cytosolic translocation of cytochrome c was measured using an ELISA kit. Antioxidants, MAPK signaling inhibitors, NADPH oxidase inhibitors, and siRNA were used to elucidate the molecular mechanism of action of the compound. RESULTS: We isolated five terthiophenes from the n-hexane fraction of E. prostrata; of these, α-terthienylmethanol possessed potent cytotoxic activity against human endometrial cancer cells (Hec1A and Ishikawa) (IC50<1µM). The growth inhibitory effect of α-terthienylmethanol was mediated by the induction of apoptosis, as shown by the accumulation of sub-G1 and apoptotic cells. In addition, α-terthienylmethanol triggered caspase activation and cytochrome c release into the cytosol in a time-dependent manner. Moreover, α-terthienylmethanol increased the intracellular level of ROS and decreased that of GSH, and the antioxidants N-acetyl-l-cysteine and catalase significantly attenuated α-terthienylmethanol-induced apoptosis. We further demonstrated that inhibition of the NADPH oxidase attenuated α-terthienylmethanol-induced cell death and ROS accumulation in endometrial cancer cells. CONCLUSION: Overall, these results suggest that α-terthienylmethanol, a naturally occurring terthiophene isolated from E. prostrata, induces apoptosis in human endometrial cancer cells by ROS production, partially via NADPH oxidase.

8,8'-Bieckol, isolated from edible brown algae, exerts its anti-inflammatory effects through inhibition of NF-κB signaling and ROS production in LPS-stimulated macrophages.

Ecklonia cava (E. cava) is an abundant brown alga that contains high levels of phlorotannins, which are unique marine polyphenolic compounds. It has been suggested that E. cava phlorotannins exert anti-inflammatory effects. However, the anti-inflammatory effects and underlying molecular mechanism exerted by 8,8'-bieckol isolated from E. cava have not been reported. Thus, in this study, we examined the anti-inflammatory effects of 8,8'-bieckol on lipopolysaccharide (LPS)-stimulated primary macrophages and RAW 264.7 macrophages. We found that 8,8'-bieckol suppressed key inflammatory mediator [i.e., nitric oxide (NO) and prostaglandin E2 (PGE2)] production in both primary and RAW 264.7 macrophages. 8,8'-Bieckol inhibited NO by suppressing LPS-induced expression of inducible nitric oxide synthase (iNOS) at the mRNA and protein levels in primary macrophages and RAW 264.7 cells. In addition, 8,8'-bieckol decreased the production and mRNA expression of the inflammatory cytokine interleukin-6 (IL-6), but not tumor necrosis factor (TNF)-α, in RAW 264.7 cells. Moreover, 8,8'-bieckol treatment diminished transactivation of nuclear factor-kappa B (NF-κB) and nuclear translocation of the NF-κB p65 subunit and suppressed LPS-induced intracellular reactive oxygen species (ROS) production in macrophages. Furthermore, 8,8'-bieckol markedly reduced mortality in LPS-induced septic mice. Taken together, these data indicate that the anti-inflammatory properties of 8,8'-bieckol are associated with the suppression of NO, PGE2, and IL-6 via negative regulation of the NF-κB pathway and ROS production in LPS-stimulated RAW 264.7 cells. Moreover, 8,8'-bieckol protects mice from endotoxin shock.

RSF1 is a positive regulator of NF-κB-induced gene expression required for ovarian cancer chemoresistance.

Overexpression or amplification of the RSF1 gene has been associated with poor prognosis in various human cancers, including ovarian cancer. In previous work, RSF1 was identified as an amplified gene that facilitated the development of paclitaxel-resistant ovarian cancer. In the present study, we further demonstrated that RSF1 expression inversely correlated with paclitaxel response in patients with ovarian cancer and the mouse xenograft model. In addition, RSF1-overexpressing paclitaxel-resistant ovarian cancer cell lines were found to express elevated levels of genes regulated by NF-κB, including some involved with the evasion of apoptosis (CFLAR, XIAP, BCL2, and BCL2L1) and inflammation (PTGS2). In addition, ectopic expression of RSF1 using Tet-off inducible SKOV3 cells significantly enhanced NF-κB-dependent gene expression and transcriptional activation of NF-κB. An RSF1 knockdown using short hairpin RNAs suppressed these same pathways. Moreover, pretreatment with NF-κB inhibitors or downregulation of NF-κB-regulated gene expression considerably enhanced paclitaxel sensitivity in RSF1-overexpressing OVCAR3 and/or RSF1-induced SKOV3 cells. A coimmunoprecipitation assay revealed that RSF1 interacts with NF-κB and CREB-binding protein, a ubiquitous coactivator for NF-κB. Recruitment of RSF1 to the NF-κB binding element in the PTGS2 and XIAP promoters was demonstrated by the chromatin immunoprecipitation assay. Furthermore, hSNF2H, a well-known binding partner of RSF1, was partially involved in the interaction between RSF1 and NF-κB. Taken together, these data suggest that RSF1 may function as a coactivator for NF-κB, consequently augmenting expression of genes necessary for the development of chemoresistance in ovarian cancer cells.

Artemisia leaf extract induces apoptosis in human endometriotic cells through regulation of the p38 and NFκB pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia leaves have long been used for the treatment of gynecological disorders, including infertility and dysmenorrhea, which can be commonly caused by endometriosis. In the present study, we investigated the effect of Artemisia princeps extract (APE) on the cell growth and apoptosis of human endometriotic cells. MATERIALS AND METHODS: MTT assays and FACS analysis using PI and Annexin staining were performed to study cell viability, cell cycle progression, and apoptosis. We also explored the mechanism of APE-induced effects by evaluating the activation of caspases, Akt, p38, and NFκB. The expressions of XIAP, Bcl-2, and Bcl-xL were measured by real-time RT-PCR and Western blot analyses. RESULTS: APE significantly inhibited the cell viability of 11Z and 12Z human endometriotic epithelial cells. Interestingly, endometriotic cells were more sensitive to APE treatment than immortalized endometrial cells (HES). Treatment with APE induced apoptosis of 11Z cells in a time-dependent manner, as shown by accumulation of sub G1 and apoptotic cell populations. In addition, treatment with APE stimulated the activation of caspase -3, -8, and -9 in a dose- and time-dependent manner. Furthermore, p38 was activated by APE treatment, and the p38 inhibitor SB203580 markedly inhibited APE-induced cell death in 11Z cells. Moreover, treatment with APE suppressed the activation of NFκB and the expressions of anti-apoptotic factors such as XIAP, Bcl-2, and Bcl-xL. CONCLUSION: These results indicate that APE is a potential anti-endometriotic agent, acting to induce apoptosis of endometrial cells through the modulation of the p38 and NFκB pathways.

Deer (Cervus elaphus) antler extract suppresses adhesion and migration of endometriotic cells and regulates MMP-2 and MMP-9 expression.

ETHNOPHARMACOLOGICAL RELEVANCE: Deer antler has been used for centuries as medicine for a wide range of health problems, including various women's diseases. However, there is a safety concern related to its use in hormone-sensitive conditions, such as breast cancer and endometriosis. In the present study, we investigated the effect of deer (Cervus elaphus) antler extract (DAE) on adhesion and migration of human endometriotic cells. MATERIALS AND METHODS: Adhesion, wound-healing, and transwell migration assays were performed in endometriotic cells 11Z and 12Z. Expression of matrix metalloproteinase (MMP)-2, MMP-9, TNF-α, and IL-6 were measured by real-time RT-PCR and Western blot analysis. RESULTS: DAE (50 and 100µg/ml) decreased the adhesion of 11Z and 12Z cells on peritoneal mesothelial Met5-A cells. Wound-healing and transwell migration assays revealed that DAE (50 and 100µg/ml) inhibited migration in 11Z and 12Z cells. It was further demonstrated that treatment with DAE (50 and 100µg/ml) significantly decreased the levels of MMP-2, MMP-9, TNF-α, and IL-6. CONCLUSIONS: These results indicate that DAE is a potential anti-endometriotic agent to inhibit the adhesion and migration of endometrial cells through the suppression of various related molecules.

6,6'-Bieckol, isolated from marine alga Ecklonia cava, suppressed LPS-induced nitric oxide and PGE2 production and inflammatory cytokine expression in macrophages: the inhibition of NFκB.

Ecklonia cava is an edible brown alga that contains high levels of phlorotannins, which are unique marine polyphenolic compounds. In the present study, we investigated the anti-inflammatory effects and the underlying molecular mechanism of phlorotannin 6,6'-bieckol, which is an active component isolated from E. cava, on lipopolysaccharide (LPS)-stimulated primary macrophages and RAW 264.7 macrophage cells. 6,6'-Bieckol was found to inhibit nitric oxide (NO) and prostaglandin E2 (PGE2) production and to suppress the LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the mRNA and protein levels. In addition, 6,6'-bieckol downregulated the production and mRNA expression of the inflammatory cytokines TNF-α and IL-6. Moreover, pretreatment with 6,6'-bieckol decreased LPS-induced transactivation of nuclear factor-kappa B (NFκB) and nuclear translocation of p50 and p65 subunits of NFκB. Furthermore, chromatin immunoprecipitation assay revealed that 6,6'-bieckol inhibited LPS-induced NFκB binding to the TNF-α and IL-6 promoters. Taken together, these data suggest that the anti-inflammatory properties of 6,6'-bieckol are related to the down-regulation of iNOS, COX-2, and pro-inflammatory cytokines through the negative regulation of the NFκB pathway in LPS-stimulated macrophages.

Eupatilin, a dietary flavonoid, induces G2/M cell cycle arrest in human endometrial cancer cells.

This study is the first to investigate the antiproliferative effect of eupatilin in human endometrial cancer cells. Eupatilin, a naturally occurring flavonoid isolated from Artemisia princeps, has anti-inflammatory, anti-oxidative, and anti-tumor activities. In the present study, we investigated the potential effect of eupatilin on cell growth and its molecular mechanism of action in human endometrial cancer cells. Eupatilin was more potent than cisplatin in inhibiting cell viability in the human endometrial cancer cell lines Hec1A and KLE. Eupatilin showed relatively low cytotoxicity in normal human endometrial cells HES and HESC cells when compared to cisplatin. Eupatilin induced G2/M phase cell cycle arrest in a time- and dose-dependent manner, as indicated by flow cytometry analysis. In addition, treatment of Hec1A cells with eupatilin resulted in a significant increase in the expression of p21(WAF1/CIP1) and in the phosphorylation of Cdc25C and Cdc2. Knockdown of p21 using specific siRNAs significantly compromised eupatilin-induced cell growth inhibition. Interestingly, levels of mutant p53 in Hec1A cells decreased markedly upon treatment with eupatilin, and p53 siRNA significantly increased p21 expression. Moreover, eupatilin modulated the phosphorylation of protein kinases ERK1/2, Akt, ATM, and Chk2. These results suggest that eupatilin inhibits the growth of human endometrial cancer cells via G2/M phase cell cycle arrest through the up-regulation of p21 by the inhibition of mutant p53 and the activation of the ATM/Chk2/Cdc25C/Cdc2 checkpoint pathway.