Yun Seon Song

Caffeic acid phenethyl ester, a component of beehive propolis, is a novel selective estrogen receptor modulator.

Caffeic acid phenethyl ester (CAPE) is an active ingredient of beehive propolis with a structure similar to phenolic acid. The estrogenic effects of propolis were previously demonstrated through the activation of an estrogen receptor. To identify the estrogenic properties of propolis, CAPE was evaluated using in vitro and in vivo methods. CAPE showed selective binding affinity to human estrogen receptor β (hERβ) rather than hERα. CAPE also reduced ERα expression in MCF‐7 and MDA 231 cells. In the yeast estrogen receptor transcription assay, CAPE produced the transcriptional activity of estrogen‐responsive element with EC50 values of 3.72 × 10−6 M. CAPE did not increase the growth of MCF‐7 estrogen receptor‐positive breast cancer cells in doses ranging from 10−7 to 10−5 M. In order to understand how CAPE acts in animals, CAPE was tested by a uterotrophic bioassay. Treatment with CAPE (100, 500 mg/kg) did not increase the uterine weight relative to 3 μg/kg 17β‐estradiol treatment. The results indicate that CAPE, which is a selective agonist to hERβ, but does not show any estrogenic effect on estrogen receptor‐positive breast cancer cells and in immature rat uterine tissue, is a potential selective estrogen receptor modulator. Copyright

Psoralidin, a coumestan analogue, as a novel potent estrogen receptor signaling molecule isolated from Psoralea corylifolia.

A novel biological activity of psoralidin as an agonist for both estrogen receptor (ER)α and ERβ agonist has been demonstrated in our study. Psoralidin has been characterized as a full ER agonist, which activates the classical ER-signaling pathway in both ER-positive human breast and endometrial cell lines as well as non-human cultured cells transiently expressing either ERα or ERβ. The estrogenic activity was determined using the relative expression levels of either reporter or the endogenous genes dependent on the agonist-bound ER to the estrogen response element (ERE). Psoralidin at 10 μM was able to induce the maximum reporter gene expression corresponding to that of E2-treated cells and such activation of the ERE-reporter gene by psoralidin was completely abolished by the cotreatment of a pure ER antagonist, implying that the biological activities of psoralidin are mediated by ER. Psoralidin was also able to induce the endogenous estrogen-responsive gene, pS2, in human breast cancer cells MCF-7. It was observed that activation of the classical ER-signaling pathway by psoralidin is mediated via induction of ER conformation by psoralidin and direct binding of the psoralidin-ER complex to the EREs present in the promoter region of estrogen-responsive genes, as shown by chromatin immunoprecipitation assay results. Finally, molecular docking of psoralidin to the ligand binding pocket of the ERα showed that psoralidin is able to mimic the binding interactions of E2, and thus, it could act as an ER agonist in the cellular environment.

Selective Estrogen Receptor Modulation by Larrea nitida on MCF-7 Cell Proliferation and Immature Rat Uterus.

Larrea nitida is a plant that belongs to the Zygophyllaceae family and is widely used in South America to treat inflammatory diseases, tumors and menstrual pain. However, its pharmacological activity remains unclear. In this study we evaluated the property of selective estrogen receptor modulator (SERM) of Larrea nitida extracts (LNE) as a phytoestrogen that can mimic, modulate or disrupt the actions of endogenous estrogens, depending on the tissue and relative amount of other SERMs. To investigate the property of SERM of LNE, we performed MCF-7 cell proliferation assays, estrogen response element (ERE)-luciferase reporter gene assay, human estrogen receptor (hER) binding assays and in vivo uterotrophic assay. To gain insight into the active principles, we performed a bioassay-guided analysis of LNE employing solvents of various polarities and using classical column chromatography, which yielded 16 fractions (LNs). LNE showed high binding affinities for hERα and hERβ with IC50 values of 1.20 ×10−7 g/ml and 1.00×10−7 g/ml, respectively. LNE induced 17β-estradiol (E2)-induced MCF-7 cell proliferation, however, it reduced the proliferation in the presence of E2. Furthermore, LNE had an atrophic effect in the uterus of immature rats through reducing the expression level of progesterone receptor (PR) proteins. LN08 and LN10 had more potent affinities for binding on hER α and β than other fractions. Our results indicate that LNE had higher binding affinities for hERβ than hERα, and showed SERM properties in MCF-7 breast cancer cells and the rat uterus. LNE may be useful for the treatment of estrogen-related conditions, such as female cancers and menopause.

Pharmacokinetics and Biodistribution of Human Serum Albumin-TIMP-2 Fusion Protein Using Near-Infrared Optical Imaging

PURPOSE TIMP-2 has been studied as an attractive cancer therapeutic candidate, and a TIMP-2 fusion protein (HSA/TIMP-2) displayed effective anticancer activity, despite a lack of information about its pharmacokinetics (PK) and biodistribution. The purpose of this work was to assess the PK and biodistribution of HSA/TIMP-2 as well as to quantify accumulated HSA/TIMP-2 in tumors. METHODS Cy5.5 near-infrared (NIR) fluorescence was conjugated to the HSA/TIMP-2 protein (Cy5.5-HSA/TIMP-2) for monitoring spatio-temporal changes in vivo. For PK and biodistribution analysis, 0.2 μg/g body weight of Cy5.5-HSA/TIMP-2 was injected into MAT-LyLu prostate tumor xenografts, which were then imaged using an IVIS-200 optical imaging system. To quantify the accumulated HSA/TIMP-2 in tumors, we introduced a standard curve with depth-corrected fluorescence measurement. RESULTS In the vascular tube formation assay with human umbilical vein endothelial cells (HUVECs), Cy5.5-HSA/TIMP-2 showed an antiangiogenic effect. In prostate cancer xenografts, Cy5.5-HSA/TIMP-2 exhibited a prolongation of blood half-life to 19.6 h and relatively preferential distribution to the tumor. The amount of tumor-accumulated Cy5.5-HSA/TIMP-2 was calculated to be 4.5 ± 0.5 ng/g body weight at 2 days, representing 2.25 ± 0.25% of the initial dose. CONCLUSIONS We evaluated the pharmacokinetic profile and biodistribution of HSA/TIMP-2 with favorable results, providing new information for more effective approaches to cancer therapeutics using HSA/TIMP-2. Additionally, real-time in vivo fluorescence imaging analysis using a depth-corrected standard curve may serve as a platform to quantify biodistributed drug in anticancer therapeutic studies.

Novel Antidepressant-Like Activity of Caffeic Acid Phenethyl Ester Is Mediated by Enhanced Glucocorticoid Receptor Function in the Hippocampus

Caffeic acid phenethyl ester (CAPE) is an active component of propolis that has a variety of potential pharmacological effects. Although we previously demonstrated that propolis has antidepressant-like activity, the effect of CAPE on this activity remains unknown. The present study assessed whether treatment with CAPE (5, 10, and 20 µmol/kg for 21 days) has an antidepressant-like effect in mice subjected to chronic unpredictable stress via tail suspension (TST) and forced swim (FST) tests. CAPE administration induced behaviors consistent with an antidepressant effect, evidenced by decreased immobility in the TST and FST independent of any effect on serum corticosterone secretion. Western blots, conducted subsequent to behavioral assessment, revealed that CAPE significantly decreased glucocorticoid receptor phosphorylation at S234 (pGR(S234)), resulting in an increased pGR(S220/S234) ratio. We also observed negative correlations between pGR(S220)/(S234) and p38 mitogen-activated protein kinase (p38MAPK) phosphorylation, which was decreased by CAPE treatment. These findings suggest that CAPE treatment exerts an antidepressant-like effect via downregulation of p38MAPK phosphorylation, thereby contributing to enhanced GR function.

Anti-inflammatory Effect of Glucagon Like Peptide-1 Receptor Agonist, Exendin-4, through Modulation of IB1/JIP1 Expression and JNK Signaling in Stroke

Glucagon like peptide-1 (GLP-1) stimulates glucose-dependent insulin secretion. Dipeptidyl peptidase-4 (DPP-4) inhibitors, which block inactivation of GLP-1, are currently in clinical use for type 2 diabetes mellitus. Recently, GLP-1 has also been reported to have neuroprotective effects in cases of cerebral ischemia. We therefore investigated the neuroprotective effects of GLP-1 receptor (GLP-1R) agonist, exendin-4 (ex-4), after cerebral ischemia-reperfusion injury. Transient middle cerebral artery occlusion (tMCAO) was induced in rats by intracerebroventricular (i.c.v.) administration of ex-4 or ex9-39. Oxygen-glucose deprivation was also induced in primary neurons, bEnd.3 cells, and BV-2. Ischemia-reperfusion injury reduced expression of GLP-1R. Additionally, higher oxidative stress in SOD2 KO mice decreased expression of GLP-1R. Downregulation of GLP-1R by ischemic injury was 70% restored by GLP-1R agonist, ex-4, which resulted in significant reduction of infarct volume. Levels of intracellular cyclic AMP, a second messenger of GLP-1R, were also increased by 2.7-fold as a result of high GLP-1R expression. Moreover, our results showed that ex-4 attenuated pro-inflammatory cyclooxygenase-2 (COX-2) and prostaglandin E2 after MCAO. C-Jun NH2 terminal kinase (JNK) signaling, which stimulates activation of COX-2, was 36% inhibited by i.c.v. injection of ex-4 at 24 h. Islet-brain 1 (IB1), a scaffold regulator of JNK, was 1.7-fold increased by ex-4. GLP-1R activation by ex-4 resulted in reduction of COX-2 through increasing IB1 expression, resulting in anti-inflammatory neuroprotection during stroke. Our study suggests that the anti-inflammatory action of GLP-1 could be used as a new strategy for the treatment of neuroinflammation after stroke accompanied by hyperglycemia.

Neuroprotective effect of mesenchymal stem cell through complement component 3 downregulation after transient focal cerebral ischemia in mice

Bone marrow-derived mesenchymal stem cells (MSCs) are used in stroke treatment despite the poor understanding of its mode of action. The immune suppressive and anti-inflammatory properties of MSCs possibly play important roles in regulating neuroinflammation after stroke. We investigated whether MSCs reduce the inflammatory complement component 3 (C3) levels, thus, providing neuroprotection during stroke. Mice were subjected to transient focal cerebral ischemia (tFCI), after which MSCs were intravenously injected. The infarct volume of the brain was reduced in MSC-injected tFCI mice, and C3 expression was significantly reduced in both the brain and the blood. Additionally, the profiles of other inflammatory mediators demonstrated neuroprotective changes in the MSCs-treated group. In order to analyze the effect of MSCs on neurons during cerebral ischemia, primary cortical neurons were co-cultured with MSCs under oxygen-glucose deprivation (OGD). Primary neurons co-cultured with MSCs exhibited reduced levels of C3 expression and increased protection against OGD, indicating that treatment with MSCs reduces excessive C3 expression and rescues ischemia-induced neuronal damage. Our finding suggests that reduction of C3 expression by MSCs can help to ameliorate ischemic brain damage, offering a new neuroprotective strategy in stroke therapy.

Characterization of Phase I and Phase II Hepatic Metabolism and Reactive Intermediates of Larrea nitida Cav. and Its Lignan Compounds

Larrea nitida Cav. (LNC), which belongs to the family Zygophyllaceae, is widely indigenous and used in South America to treat various pathological conditions. It contains the antioxidant and antiinflammatory but toxic nordihydroguaiaretic acid (NDGA) as well as O‐methylated metabolite of NDGA (MNDGA) as bioactive compounds. The hepatic metabolism‐based toxicological potential of extracts of LNC (LNE), NDGA, and MNDGA has not previously been reported. The present study aimed to characterize the phase I and phase II hepatic metabolism and reactive intermediates of LNE, NDGA, and MNDGA and their effects on the major drug‐metabolizing enzymes in vitro and ex vivo. A methanol extract of LNC collected from Chile as well as NDGA and MNDGA isolated from LNE were subjected to metabolic stability assays in liver microsomes in the presence of the cofactors reduced nicotinamide dinucleotide phosphate (NADPH) and/or uridine 5′‐diphosphoglucuronic acid (UDPGA). Cytochrome P450 (CYP) inhibition assays were performed using CYP isozyme‐specific model substrates to examine the inhibitory activities of LNE, NDGA, and MNDGA, which were expressed as % inhibition and IC50 values. Ex vivo CYP induction potential was investigated in the liver microsomes prepared from the rats intraperitoneally administered with LNE. Glutathione (GSH) adduct formation was monitored by LC‐MS3 analysis of the microsomal incubation samples with either NDGA or MNDGA and an excess of GSH to determine the formation of electrophilic reactive intermediates. Both NDGA and MNDGA were stable to NADPH‐dependent phase I metabolism, but labile to glucuronide conjugation. LNE, NDGA, and MNDGA showed significant inhibitory effects on CYP1A2, 2C9, 2D6, and/or 3A4, with IC50 values in the micromolar range. LNE was found to be a CYP1A2 inducer in ex vivo rat experiments, and mono‐ and di‐GSH adducts of both NDGA and MNDGA were identified by LC‐MS3 analysis. Our study suggests that hepatic clearance is the major elimination route for the lignans NDGA and MNDGA present in LNE. These lignans may possess the ability to modify biomacromolecules via producing reactive intermediates. In addition, LNE, NDGA, and MNDGA are found to be inhibitors for various CYP isozymes such as CYP2C9 and 3A4. Thus, the consumption of LNC as an herbal preparation or NDGA may cause metabolism‐driven herb–drug interactions. Copyright

Estrogenic effects of phytoestrogens derived from Flemingia strobilifera in MCF-7 cells and immature rats

Phytoestrogen (PE) has received considerable attention due to the physiological significance of its estrogenicity. Flemingia strobilifera (FS) has been used as a folk medicine in Asia for the treatment of inflammation, cancer, and infection; however, the estrogenic effects and chemical components of FS have not yet been reported. We aimed to uncover the estrogenic properties and PEs derived from FS using phytochemical and pharmacological evaluation. PEs from FS extract (FSE) were analyzed by NMR, HPLC, and MS. To evaluate estrogenic activity, FSE and its compounds were evaluated by in vitro and in vivo assays, including human estrogen receptor alpha (hERα) binding, estrogen response element (ERE)-luciferase reporter assays, and uterotrophic assays. FSE and its compounds 1–5 showed binding affinities for hERα and activated ERE transcription in MCF-7 cells. Additionally, FSE and compounds 1–5 induced MCF-7 cell proliferation and trefoil factor 1 (pS2) expression. In immature female rats, significant increases in uterine weight and pS2 gene were observed in FSE-treated groups. We identified estrogenic activities of FSE and its bioactive compounds, suggesting their possible roles as PEs via ERs. PEs derived from FSE are promising candidates for ER-targeted therapy for post-menopausal symptoms.

TLR5 Activation through NF-κB Is a Neuroprotective Mechanism of Postconditioning after Cerebral Ischemia in Mice

Postconditioning has been shown to protect the mouse brain from ischemic injury. However, the neuroprotective mechanisms of postconditioning remain elusive. We have found that toll-like receptor 5 (TLR5) plays an integral role in postconditioning-induced neuroprotection through Akt/nuclear factor kappa B (NF-κB) activation in cerebral ischemia. Compared to animals that received 30 min of transient middle cerebral artery occlusion (tMCAO) group, animals that also underwent postconditioning showed a significant reduction of up to 60.51% in infarct volume. Postconditioning increased phospho-Akt (p-Akt) levels and NF-κB translocation to the nucleus as early as 1 h after tMCAO and oxygen-glucose deprivation. Furthermore, inhibition of Akt by Akt inhibitor IV decreased NF-κB promoter activity after postconditioning. Immunoprecipitation showed that interactions between TLR5, MyD88, and p-Akt were increased from postconditioning both in vivo and in vitro. Similar to postconditioning, flagellin, an agonist of TLR5, increased NF-κB nuclear translocation and Akt phosphorylation. Our results suggest that postconditioning has neuroprotective effects by activating NF-κB and Akt survival pathways via TLR5 after cerebral ischemia. Additionally, the TLR5 agonist flagellin can simulate the neuroprotective mechanism of postconditioning in cerebral ischemia.