GREB1: An evolutionarily conserved protein with a glycosyltransferase domain links ERα glycosylation and stability to cancer.

What covalent modifications control the temporal ubiquitination of ERα and hence the duration of its transcriptional activity remain poorly understood. We show that GREB1, an ERα-inducible enzyme, catalyzes O-GlcNAcylation of ERα at residues T553/S554, which stabilizes ERα protein by inhibiting association with the ubiquitin ligase ZNF598. Loss of GREB1-mediated glycosylation of ERα results in reduced cellular ERα levels and insensitivity to estrogen. Higher GREB1 expression in ERα+ve breast cancer is associated with greater survival in response to tamoxifen, an ERα agonist. Mice lacking Greb1 exhibit growth and fertility defects reminiscent of phenotypes in ERα-null mice. In summary, this study identifies GREB1, a protein with an evolutionarily conserved domain related to DNA-modifying glycosyltransferases of bacteriophages and kinetoplastids, as the first inducible and the only other (apart from OGT) O-GlcNAc glycosyltransferase in mammalian cytoplasm and ERα as its first substrate.

Targeting NF-κB Signaling for Multiple Myeloma.

Multiple myeloma (MM) is the second most common hematologic malignancy in the world. Even though survival rates have significantly risen over the past years, MM remains incurable, and is also far from reaching the point of being managed as a chronic disease. This paper reviews the evolution of MM therapies, focusing on anti-MM drugs that target the molecular mechanisms of nuclear factor kappa B (NF-κB) signaling. We also provide our perspectives on contemporary research findings and insights for future drug development.

Indian Hedgehog links obesity to development of hepatocellular carcinoma.

Obesity increases the risk of hepatocellular carcinoma (HCC), but precise identification and characterization of druggable oncogenic pathways that contribute to the progression of NAFLD to HCC, and hence to the increased incidence and aggressiveness of HCC in obese individuals is lacking. In this regard, we demonstrate that the Indian Hedgehog (Ihh) signaling pathway is upregulated in the fatty livers of mice consuming a high fat diet, and furthermore sustained in HCC tumors specifically within the context of a NAFLD microenvironment. Using a diet-induced mouse model of HCC wherein only obese mice develop HCC, targeted ablation of hepatocyte-secreted Ihh results in a decreased tumor burden and lower grade tumors. Ihh activation regulates the transdifferentiation of ciliated stellate cells and proliferation of Epcam+ ductal cells to promote fibrosis. Mechanistically, increased expression of hitherto uncharacterized effectors of Hh pathway, namely Myc and Tgf-ß2 is critical to the observed physiology. This pro-tumorigenic response is driven by increased expression of Wnt5a to effect a poorly-differentiated and invasive tumor phenotype. Wnt5a secreted from activated stellate cells act on Ror2-expressing hepatocytes. We further demonstrate that Wnt5a expression is also elevated in poorly-differentiated HCC cells, suggesting that these ligands are also able to function in an autocrine positive feedback manner to sustain poorly-differentiated tumors. Taken together, our study provides a mechanistic understanding for how Ihh signaling promotes HCC tumorigenesis specifically in obese mice. We propose that therapeutic targeting of the Hh pathway offers benefit for patients with dietary / NAFLD-driven steatotic HCC.

Ikk2 regulates cytokinesis during vertebrate development.

NFκB signaling has a pivotal role in regulation of development, innate immunity, and inflammation. Ikk2 is one of the two critical kinases that regulate the NFκB signaling pathway. While the role of Ikk2 in immunity, inflammation and oncogenesis has received attention, an understanding of the role of Ikk2 in vertebrate development has been compounded by the embryonic lethality seen in mice lacking Ikk2. We find that despite abnormal angiogenesis in IKK2 zygotic mutants of zebrafish, the maternal activity of Ikk2 supports embryogenesis and maturation of fertile animals and allows to study the role of IKK2 in development. Maternal-zygotic ikk2 mutants represent the first vertebrates globally devoid of maternal and zygotic Ikk2 activity. They are defective in cell proliferation as evidenced by abnormal cytokinesis, nuclear enlargement and syncytialisation of a significant portion of blastoderm. We further document that reduced phosphorylation of Aurora A by Ikk2 could underlie the basis of these defects in cell division.

PRDM15 safeguards naive pluripotency by transcriptionally regulating WNT and MAPK-ERK signaling.

The transcriptional network acting downstream of LIF, WNT and MAPK-ERK to stabilize mouse embryonic stem cells (ESCs) in their naive state has been extensively characterized. However, the upstream factors regulating these three signaling pathways remain largely uncharted. PR-domain-containing proteins (PRDMs) are zinc-finger sequence-specific chromatin factors that have essential roles in embryonic development and cell fate decisions. Here we characterize the transcriptional regulator PRDM15, which acts independently of PRDM14 to regulate the naive state of mouse ESCs. Mechanistically, PRDM15 modulates WNT and MAPK-ERK signaling by directly promoting the expression of Rspo1 (R-spondin1) and Spry1 (Sprouty1). Consistent with these findings, CRISPR-Cas9-mediated disruption of PRDM15-binding sites in the Rspo1 and Spry1 promoters recapitulates PRDM15 depletion, both in terms of local chromatin organization and the transcriptional modulation of these genes. Collectively, our findings uncover an essential role for PRDM15 as a chromatin factor that modulates the transcription of upstream regulators of WNT and MAPK-ERK signaling to safeguard naive pluripotency.

DEAD-box helicase DP103 defines metastatic potential of human breast cancers.

Despite advancement in breast cancer treatment, 30% of patients with early breast cancers experience relapse with distant metastasis. It is a challenge to identify patients at risk for relapse; therefore, the identification of markers and therapeutic targets for metastatic breast cancers is imperative. Here, we identified DP103 as a biomarker and metastasis-driving oncogene in human breast cancers and determined that DP103 elevates matrix metallopeptidase 9 (MMP9) levels, which are associated with metastasis and invasion through activation of NF-κB. In turn, NF-κB signaling positively activated DP103 expression. Furthermore, DP103 enhanced TGF-ß-activated kinase-1 (TAK1) phosphorylation of NF-κB-activating IκB kinase 2 (IKK2), leading to increased NF-κB activity. Reduction of DP103 expression in invasive breast cancer cells reduced phosphorylation of IKK2, abrogated NF-κB-mediated MMP9 expression, and impeded metastasis in a murine xenograft model. In breast cancer patient tissues, elevated levels of DP103 correlated with enhanced MMP9, reduced overall survival, and reduced survival after relapse. Together, these data indicate that a positive DP103/NF-κB feedback loop promotes constitutive NF-κB activation in invasive breast cancers and activation of this pathway is linked to cancer progression and the acquisition of chemotherapy resistance. Furthermore, our results suggest that DP103 has potential as a therapeutic target for breast cancer treatment.

Secreted frizzled related proteins: Implications in cancers.

The Wnt (wingless-type) signaling pathway plays an important role in embryonic development, tissue homeostasis, and tumor progression becaluse of its effect on cell proliferation, migration, and differentiation. Secreted frizzled-related proteins (SFRPs) are extracellular inhibitors of Wnt signaling that act by binding directly to Wnt ligands or to Frizzled receptors. In recent years, aberrant expression of SFRPs has been reported to be associated with numerous cancers. As gene expression of SFRP members is often lost through promoter hypermethylation, inhibition of methylation through the use of epigenetic modifying agents could renew the expression of SFRP members and further antagonize deleterious Wnt signaling. Several reports have described epigenetic silencing of these Wnt signaling antagonists in various human cancers, suggesting their possible role as tumor suppressors. SFRP family members thus come across as potential tools in combating Wnt-driven tumorigenesis. However, little is known about SFRP family members and their role in different cancers. This review comprehensively covers all the available information on the role of SFRP molecules in various human cancers.

Anti-inflammatory effects of (Z)-ligustilide through suppression of mitogen-activated protein kinases and nuclear factor-κB activation pathways.

The roots of Angelica tenuissima have been commonly used for the treatment of cardiovascular diseases and menstrual discomfort in Asian countries, such as China and Korea. The primary volatile flavor components are essential oil ingredients, phthalide lactones. In this study, (Z)-ligustilide was tested for its anti-inflammatory activities in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. We found that (Z)-ligustilide strongly inhibitis the induction of LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at both the mRNA and protein levels in a dose-dependent manner. The transcriptional activity of nuclear factor kappa B (NF-B) was also down-regulated in a concentration-dependent manner. Further study revealed that (Z)-ligustilide inhibited the phosphorylation and subsequent degradation of IBα, an inhibitor protein of NF-B. In addition, (Z)-ligustilide inhibited the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK) and c-Jun NH(2)-terminal kinase (JNK) in a dose-dependent manner. Taken together, these data suggest that (Z)-ligustilide can exert its antiinflammatory effects by regulating the NF-B and MAPK signal pathways.

Suppression of LPS-induced inflammatory and NF-κB responses by anomalin in RAW 264.7 macrophages.

The treatment of inflammatory diseases today is largely based on interrupting the synthesis or action of the mediators that drive the host's response to injury. It is on the basis of this concept that most of the anti-inflammatory drugs have been developed. In our continuous search for novel anti-inflammatory agents from traditional medicinal plants, Saposhnikovia divaricata has been a focus of our investigations. Anomalin, a pyranocoumarin constituent of S. divaricata, exhibits potent anti-inflammatory activity. To clarify the cellular signaling mechanisms underlying the anti-inflammatory action of anomalin, we investigated the effect of anomalin on the production of inflammatory molecules in LPS-stimulated murine macrophages. The anomalin dose-dependently inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA and protein expression in LPS-stimulated RAW 264.7 macrophage. Molecular analysis using quantitative real time polymerase chain reaction (qRT-PCR) revealed that several pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were reduced by anomalin, and this reduction correlated with the down-regulation of the NF-κB signaling pathway. In addition, anomalin suppressed the LPS-induced phosphorylation and degradation of IκBα. To further study the mechanisms underlying its anti-inflammatory activity, an electrophoretic mobility shift assay (EMSA) using a (32) P-labeled NF-κB probe was conducted. LPS-induced NF-κB DNA binding was drastically abolished by anomalin. The present data suggest that anomalin is a major anti-inflammatory agent and may be a potential therapeutic candidate for the treatment of inflammatory disorders.

Inhibitory effects of kaurenoic acid from Aralia continentalis on LPS-induced inflammatory response in RAW264.7 macrophages.

This study investigates the anti-inflammatory effects of a diterpenoid, kaurenoic acid, isolated from the root of Aralia continentalis (Araliaceae). To determine its anti-inflammatory effects, LPS-induced RAW264.7 macrophages were treated with different concentrations of kaurenoic acid and carrageenan-induced paw edema mice model was used in vivo. Kaurenoic acid (ent-kaur-16-en-19-oic acid) dose-dependently inhibited nitric oxide (NO) production, prostaglandin E(2) (PGE(2)) release, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression at micromolar concentrations in LPS-induced RAW264.7 macrophages with IC(50) (the half maximal inhibitory concentration) values of 51.73 (±2.42) µM and 106.09 (±0.27) µM in NO production and PGE(2) release, respectively. Kaurenoic acid also dose-dependently inhibited LPS-induced activation of NF-κB as assayed by electrophorectic mobility shift assay (EMSA) and it almost abolished NF-κB DNA binding affinity at 100µM. Furthermore, the in vivo anti-inflammatory effect of kaurenoic acid was examined in a carrageenan-induced paw edema model. Eight ICR mice in each group were injected with carrageenan and observed hourly, compared with the control group. Kaurenoic acid dose-dependently reduced paw swelling up to 34.4% at 5h after induction, demonstrating inhibition in an acute inflammation model. Taken together, our data suggest that kaurenoic acid, a major diterpenoid from the root of A. continentalis shows anti-inflammatory activity and the inhibition of iNOS and COX-2 expression might be one of the mechanisms responsible for its anti-inflammatory properties.

Glycyrol induces apoptosis in human Jurkat T cell lymphocytes via the Fas-FasL/caspase-8 pathway.

Glycyrrhiza uralensis (Leguminosae) has long been used to treat inflammatory ailments, such as gastric ulcers, arthritis, and rheumatism. From this traditional herbal plant, glycyrol, a coumestan with anti-bacterial and anti-inflammatory activities, was first isolated and synthesized to test its apoptosis-inducing properties in human Jurkat cells. Flow cytometry analysis indicated that glycyrol can arrest the cell cycle in S phase and subsequently induce apoptosis in both time- and dose-dependent manners. Consequently, it was shown that caspase-8 and -9 were involved in the activation of apoptosis after glycyrol treatment. Despite its known NF- κB inhibitory activity, glycyrol did not influence the prosurvival Bcl-2 and the proapoptotic Bax. Interestingly, glycyrol was revealed to enhance the Fas level independently from p53, which even slightly decreased. Thus, glycyrol acts in a similar manner as known cytostatic drugs and may have a potential as lead for the development of drugs for cancer treatment.

Anti-Inflammatory activity of Angelica keiskei through suppression of mitogen-activated protein kinases and nuclear factor-kappaB activation pathways.

Angelica keiskei has been shown to exhibit antitumor, antioxidant, and antidiabetic activities, and the fresh leaves and dry powder are used for health food. In spite of several beneficial effects, however, the molecular mechanism or mechanisms behind anti-inflammatory activities of A. keiskei remain unclear. Thus, we investigated the effects of A. keiskei on the activities of inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. We found that the n-hexane fraction of A. keiskei (HAK) significantly inhibited LPS-induced NO and prostaglandin E(2) production and tumor necrosis factor-alpha secretion. HAK also inhibited the expression of LPS-induced iNOS and COX-2 proteins and their mRNA levels. Furthermore, we hypothesize that anti-inflammatory effects by HAK can be linked to interference with the signaling pathway of mitogen-activated protein kinases (MAPKs) and the activation pathway of nuclear factor kappaB (NF-kappaB). HAK suppressed LPS-induced c-Jun NH(2)-terminal kinase, p38, and p44/p42 MAPK activation. We also found that the cell-based assay system showed that HAK suppressed LPS-induced NF-kappaB activity in transfectant RAW 264.7 cells. In addition, the electrophoretic mobility shift assay showed the same result as in the cell-based assay system. Our data suggest that the anti-inflammatory effect of HAK is mediated through down-modulation of iNOS and COX-2 gene products by blocking the signaling pathways of MAPKs and NF-kappaB.

Anti-inflammatory activity of hispidol A 25-methyl ether, a triterpenoid isolated from Ponciri Immaturus Fructus.

The anti-inflammatory activity of hispidol A 25-methyl ether (hispidol A 25-Me ether), a triterpenoid isolated from Ponciri Immaturus Fructus, was studied in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophages. It was revealed that hispidol A 25-Me ether dose-dependently inhibits nitric oxide (NO) production by down-regulating inducible nitric oxide synthase (iNOS). It also reduces prostaglandin E(2) (PGE(2)) production by inhibiting cyclooxygenase-2 (COX-2) expression proven on both mRNA as well as on protein levels. In addition, hispidol A 25-Me ether inhibits mRNA expressions of major pro-inflammatory cytokines including the tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6). Interestingly, hispidol A 25-Me ether probably exhibits a glucocorticoid-like activity, exerting functional inhibition of NF-kappaB without inhibition of DNA binging as de novo synthesis of IkappaB-alpha was induced and thereby NF-kappaB activity was reduced. Furthermore, administrations of hispidol A 25-Me ether (1 and 10mg/kg, i.p., v/w.) were tested in two animal experiments involving acute inflammation, namely, the carrageenan-induced paw edema swelling test and the acetic acid-induced vascular permeability assay, and showed concentration-related inhibitory activities. The anti-inflammatory property of hispidol A 25-Me ether seems to resemble the effects of the class of naturally occurring anti-inflammatory agents, glucocorticoids, which inhibit transcriptions of important inflammatory mediators.

Cimiside E arrests cell cycle and induces cell apoptosis in gastric cancer cells.

Cimiside E was isolated from the Cimicifuga heracleifolia Komarov extract, which has been previously demonstrated to possess apoptotic action on gastric cancer cells. The IC(50) value of cimiside E on gastric cancer cells for 24 h was 14.58 microM. The mechanism of apoptosis was further elucidated through western blot, RT-PCR, morphology, Annexin V-FITC/PI staining and cell cycle analysis. Cell cycle arrest was induced by cimiside E in S phase at a lower concentration (30 microM) and G2/M phase at higher concentrations (60 and 90 microM). Cimiside E mediated apoptosis through the induction of the caspase cascade for both the extrinsic and intrinsic pathways. These findings suggest that cimiside E may be an effective chemopreventive agent against cancer.

Effects of schisandrin on transcriptional factors in lipopolysaccharide-pretreated macrophages.

Schisandrin is the main active ingredient isolated from Schisandra chinensis Baill. Recent studies have demonstrated that schisandrin exhibits anti-inflammatory effects in vivo and in vitro. In this study, we examined whether the order of lipopolysaccharide (LPS) treatment affects the mechanism of schisandrin anti-inflammatory activity. We found that the antiinflammatory mechanisms are not the same depending on whether macrophages were treated with schisandrin before or after LPS. The main difference is that inhibitor kappaBalpha (IkappaBalpha) degradation was not inhibited when macrophages were pretreated by LPS before schisandrin and was weakly inhibited when macrophages were pretreated by schisandrin before LPS.

Anti-inflammatory activity of prosapogenin methyl ester of platycodin D via nuclear factor-kappaB pathway inhibition.

Platycodin D (PD) isolated from Platycodi Radix has been reported to have anti-inflammatory and anti-tumor activities. In this study, we have investigated anti-inflammatory activities of prosapogenin D (PrsD) and prosapogenin D methyl ester (PrsDMe) of PD. The results indicated that PrsDMe concentration-dependently inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production, however, PrsD did not inhibit NO production in LPS-induced macrophages. Furthermore, PrsDMe inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) without appreciable cytotoxic effects. In the transfectant RAW 264.7 cells, PrsDMe was observed to reduce the level of nuclear factor-kappaB (NF-kappaB) activity. PrsDMe also inhibited the degradation of an inhibitory protein called inhibitor kappaB (IkappaB). Therefore, it was suggested that PrsDMe inhibited the expression of LPS-induced iNOS and COX-2 genes by suppressing NF-kappaB activation at the transcriptional level. Also, PrsDMe showed carrageenan-induced acute anti-inflammatory activity and the adjuvant-induced anti-arthritic activity in mice. In conclusion, we suggest that these compounds exert an anti-inflammatory effect through the regulation of the NF-kappaB pathway. The different activities of PD, PrsD and PrsDMe are based on the structure of the sugar substituent or methyl group at the C28-carboxyl position.

Anti-inflammatory effects of glycyrol isolated from Glycyrrhiza uralensis in LPS-stimulated RAW264.7 macrophages.

The anti-inflammatory effects of glycyrol, a benzofuran coumarin isolated from Glycyrrhizae Radix, were studied. Glycyrol of 5, 25 and 50 microM dose-dependently inhibited nitric oxide (NO) production by down-regulating inducible nitric oxide synthase (iNOS), and alleviated cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 macrophages, in both the mRNA and the protein. Furthermore, glycyrol dose-dependently decreased the mRNA of the pro-inflammatory cytokines IL-1beta and IL-6. LPS-induced NF-kappaB activation was prevented in RAW264.7 macrophages by inhibition of I-kappaBalpha phosphorylation. In addition, administration of glycyrol (30 and 100 mg/kg, i.p) reduced the thickness of carrageenan-induced mouse-paw edema swelling. Taken together, our results indicate that glycyrol is an important anti-inflammatory constituent of Glycyrrhizae Radix, and that its anti-inflammatory effect is attributed to the inhibition I-kappaBalpha phosphorylation.

Anti-inflammatory effects of schisandrin isolated from the fruit of Schisandra chinensis Baill.

Schisandrin is the main active ingredient isolated from the fruit of Schisandra chinensis Baill. Recent studies have demonstrated that schisandrin exhibits anti-oxidative effects in vivo. In the present study, the effect of schisandrin on plasma nitrite concentration in lipopolysaccharide (LPS)-treated mice was evaluated. It also significantly inhibited carrageenan-induced paw edema and acetic acid-induced vascular permeability in mice. Furthermore, schisandrin had a protective effect on lipopolysaccharide (LPS)-induced sepsis. In vitro, our results are the first that show that the anti-inflammatory properties of schisandrin result from the inhibition of nitric oxide (NO) production, prostaglandin E(2) (PGE(2)) release, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, which in turn results from the inhibition of nuclear factor-kappaB (NF-kappaB), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) activities in a RAW 264.7 macrophage cell line.

Comparison of suppressive effects of demethoxycurcumin and bisdemethoxycurcumin on expressions of inflammatory mediators in vitro and in vivo.

Demethoxycurcumin and bisdemethoxycurcumin are the main active ingredients isolated from Curcumae Longae Radix. Recent studies demonstrated that both compounds exhibit antioxidative and anti-inflammatory effects as well as effects on cancer cell lines. In this study, we compared the activities of demethoxycurcumin and bisdemethoxycurcumin, and both compounds were evaluated on lipopolysaccharide (LPS)-induced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), cycloxygenase-2 (COX-2) and nuclear factor-kappaB (NF-kappaB) activity in a RAW 264.7 macrophage cell line. The evaluation:results suggested that the anti-inflammatory properties of demethoxycurcumin and bisdemethoxycurcumin were attributed to the inhibition of iNOS and COX-2 expression, as initiated by the inhibition of NF-kappaB activity. Additionally, both of them significantly inhibited carrageenan-induced paw edema in mice. Taken together, all of the results showed that the suppressive effect of demethoxycurcumin was stronger than that of bisdemethoxycurcumin, indicating that the methoxy group had enhanced demethoxycurcumin's anti-inflammation effects.