Xiao-Ling Wang

Inhibitory effect of acetyl-11-keto-β-boswellic acid on androgen receptor by interference of Sp1 binding activity in prostate cancer cells

Androgen receptor (AR)-mediated signaling is crucial for the development and progression of prostate cancer (PCa). Naturally occurring phytochemicals that target the AR signaling offer significant protection against this disease. Acetyl-11-keto-beta-boswellic acid (AKBA), a compound isolated from the gum-resin of Boswellia carterii, caused G1-phase cell cycle arrest with an induction of p21(WAF1/CIP1), and a reduction of cyclin D1 as well in prostate cancer cells. AKBA-mediated cellular proliferation inhibition was associated with a decrease of AR expression at mRNA and protein levels. Furthermore, the functional biomarkers used in evaluation of AR transactivity showed suppressions of prostate-specific antigen promoter-dependent and androgen responsive element-dependent luciferase activities. Additionally, down-regulation of an AR short promoter mainly containing a Sp1 binding site suggested the essential role of Sp1 for the reduction of AR expression in cells exposed to AKBA. Interruption effect of AKBA on Sp1 binding activity but not Sp1 protein levels was further confirmed by EMSA and transient transfection with a luciferase reporter driven by three copies of the Sp1 binding site of the AR promoter. Therefore, anti-AR properties ascribed to AKBA suggested that AKBA-containing drugs could be used for the development of novel therapeutic chemicals.

Cycloartane-Type Triterpenoids from the Resinous Exudates of Commiphora opobalsamum

Eight new cycloartane-type triterpenoids, cycloartan-24-ene-1alpha,2alpha,3alpha-triol (1), 3beta-acetoxycycloartan-24-ene-1alpha,2alpha-diol (2), 1alpha-acetoxycycloartan-24-ene-2alpha,3beta-diol (3), 3beta-isovaleroyloxycycloartan-24-ene-1alpha,2alpha-diol (4), cycloartan-24-ene-1alpha,3beta-diol (5), cycloartan-23 E-ene-1alpha,2alpha,3beta,25-tetrol (6), and an epimeric mixture of 24 R,25-epoxycycloartane-1alpha,2alpha,3beta-triol (7) and 24 S,25-epoxycycloartane-1alpha,2alpha,3beta-triol (8), together with one known compound, cycloartan-24-ene-1alpha,2alpha,3beta-triol (9), were isolated from the resinous exudates of Commiphora opobalsamum. Their structures were established on the basis of mass spectrometry and multidimensional NMR spectroscopy. The cytotoxicity of compounds 1-9 was evaluated against the PC3 and DU145 human prostate tumor cell lines. All of the compounds except 1 and 5 exhibited moderate cytotoxicity against PC3 or DU145 cells with IC50 values ranging from 10.1 to 37.2 microM.

Cytotoxic clerodane diterpenoids from the leaves and twigs of Casearia balansae.

Ten new clerodane diterpenoids (1-10), caseabalansins A-G, 18-epicaseabalansin A, 2-epicaseabalansin B, and 2-epicaseabalansin C, one new triterpenoid, balansinone (11), and seven known diterpenoids (12-18) were obtained from the leaves and twigs of Casearia balansae. Compounds 1 and 2 are the first examples of clerodane diterpenoids with an oxygen bridge between C-2 and C-19, and compounds 5-7 are three new diterpenoid artifacts presumably formed during the extraction process. The structures of the new compounds were established on the basis of extensive spectroscopic data, and that of 11 was verified by single-crystal X-ray crystallographic analysis. Compound 15 showed cytotoxic activity against the tumor cell lines PC3, DU145, SKOV3, and A549 with IC₅₀ values of 4.5, 4.3, 5.1, and 5.7 μM, respectively. Compounds 1a, 2a, and 4 showed selective activity against PC3 tumor cells.

Sesquiterpenoids from myrrh inhibit androgen receptor expression and function in human prostate cancer cells.

Aim:To examine whether two naturally occurring sesquiterpenoids (ST1 and ST2) with anti-proliferative activity in prostate cancer cells inhibit androgen receptor (AR) signaling.Methods:Human prostate cancer cell lines LNCaP and PC3 were used. The expression of AR, AR translocation into the nucleus, and expression levels of AR coactivators ARA70 and steroid receptor coactivator-1 (SRC-1) in LNCaP cells were examined using real-time PCR and Western blot. Changes in prostate-specific antigen (PSA) protein levels, PSA promoter activity, and androgen response element (ARE)-mediated reporter gene activity were examined using enzyme-linked immunoabsorbent assay (ELISA) and transient transfection assays. Co-immunoprecipitation was performed to analyze the interaction between AR and the AR coactivators in ST1- and ST2-treated cells.Results:In LNCaP cells, ST1 and ST2 (40 μmol/L) led to a significant decrease in the expression of AR as well as a reduction of AR translocation into the nucleus, but had no effect on AR protein translation. ST1 and ST2 treatment also resulted in a significant decrease in the level of PSA protein secreted into the medium and was able to suppress PSA promoter-dependent and ARE-dependent luciferase activity. Furthermore, decreased expression of ARA70 and SRC-1 was observed when LNCaP cells were exposed to ST1 and ST2, which interfered with their ability to interact with AR.Conclusion:The observations suggest that suppression of AR transactivation by ST1 and ST2 may be mediated, in part, by inhibiting AR nuclear translocation and/or interfering with the interaction between AR and its coactivators ARA70 and SRC-1. Therefore, sesquiterpenoids could be developed as novel therapeutic agents for treating prostate cancer.

Diterpenoids from the twigs and leaves of Croton caudatus var. tomentosus

One new 9,10-seco-abietane derivative, crotontomentosin A (1), four new abietane-type diterpenoids, crotontomentosins B-E (2-5), one new ent-halimane-type diterpenoid, crotontomentosin F (6), along with five known diterpenoids (7-11) and one known sesquiterpenoid (12) were obtained from the twigs and leaves of Croton caudatus Geisel. var. tomentosus Hook. The structures of the compounds were established on the basis of extensive spectroscopic data. Compounds 1-4 and 11 exhibited moderate to weak inhibitory activity against the proliferation of the Hela, Hep G2, MDA-MB-231, or A549 cell lines selectively.

Associations of saposin C, Src, and androgen receptor upregulate the expression and function of androgen receptor in human prostate cancer cells

We previously demonstrated that ectopic expression of neurotrophic peptide (NP) derived from saposin C promotes androgen receptor (AR) expression and transactivation in human prostate cancer cells. This prompted us to investigate how NP or saposin C can function in cells. We constructed plasmids expressing saposin C or a chimeric peptide of a viral TAT transduction domain and saposin C (TAT‐saposin C) with His‐tag. Intracellular localization of saposin C and NP was predominantly shown in transfected cells, while TAT‐saposin C was detected around membrane and in cytosol by immunofluorescence staining. Furthermore, induction of the AR expression and activation of the AR transcriptional function were observed in cells transfected with saposin C or TAT‐saposin C, compared to control cells transfected with an empty plasmid. The effects of saposin C and TAT‐saposin C on AR activity were examined in the presence of inhibitors of GPCR, MAPK1/2, and PI3K/Akt. Interestingly, we found that these inhibitors only affect AR activities in cells with TAT‐saposin C expression but not with saposin C expression. Immunostaining images showed that co‐localization of saposin C, Src, and the AR occurred in transfected cells. Physical interactions of saposin C/NP, Src, and the AR were then demonstrated by co‐immunoprecipitation assays. Blockage of Src activity by specific inhibitor led to a decrease in the saposin C‐mediated enhancement of AR transactivity, suggesting that intracellular expression of saposin C caused stimulation of AR expression and activity by associations with Src in LNCaP cells. This effect may not be mediated by GPCR. J. Cell. Biochem. 112: 818–828, 2011.

Investigation of constituents from Cinnamomum camphora (L.) J. Presl and evaluation of their anti-inflammatory properties in lipopolysaccharide-stimulated RAW 264.7 macrophages

ETHNOPHARMACOLOGY RELEVANCEnCinnamomum camphora (L.) J. Presl has been used for the traditional medicine as a therapeutic agent of inflammation-related diseases, including sprains, rheumatic arthritis, abdominal pain, cough and bronchitis, for a long history. The aim of the present study was to illustrate anti-inflammatory substances of C. camphora and their mechanism of action, and to establish the correlations between chemical constituents and traditional uses of this plant.nnnMATERIALS AND METHODSnChemical constituents were purified by chromatographic methods, and their structures were established based on spectroscopic analysis. Lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages was adopted for evaluating the anti-inflammatory activity in vitro. The nitric oxide (NO) production assay and nuclear factor kappa B (NF-κB) dual luciferase reporter assay were used to screen anti-inflammatory constituents. The mRNA and protein levels of inflammation-related cytokines and enzymes were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR), immunoblot analysis, and enzyme linked immunosorbent assay (ELISA), respectively.nnnRESULTSnTwenty-five constituents were isolated from the EtOH extract of C. camphora. Eight constituents, covering phenylpropanoid (7), lignans (10 and 22), flavonoids (16-18), coumarin (21), and terpenoid (24) significantly inhibited LPS-stimulated NO production with maximum inhibition rates (MIRs) of ≥u202f80%, and thus were verified to be the anti-inflammatory substances of this ethnomedical plant. (+)-Episesaminone (SMO, 22) and 3S-(+)-9-oxonerolidol (NLD, 24) blocked NF-κB activation via inducing IκBα expression. Moreover, SMO and NLD inhibited productions of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and prostaglandin E2 (PGE2), and alleviated increased mRNA and protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), and matrix metallopeptidase-9 (MMP-9) in LPS-stimulated RAW 264.7 macrophages.nnnCONCLUSIONSnThe ethnomedical use of C. camphora for the treatment of inflammation-related diseases was attributed to the combined in vitro anti-inflammatory activities of phenylpropanoid, lignan, flavonoid, coumarin, and terpenoid. SMO and NLD were found to be new molecules with in vitro anti-inflammatory activities, which are achieved by inhibiting NF-κB regulated inflammatory response.

Protective effect of the ethanol extract from Ligusticum chuanxiong rhizome against streptozotocin-induced diabetic nephropathy in mice.

ETHNOPHARMACOLOGY RELEVANCEnRhizome of Ligusticum chuanxiong Hort. (Abbreviated as LC) is a frequently prescribed component in plenty of traditional Chinese medicine (TCM) formulas which are used to treat diabetic nephropathy (DN). The aims of the present study are to investigate the protective effect of the ethanol extract of LC rhizome (EEL) against DN in vivo, evaluate its potential mechanism, and find the evidence supporting its enthopharmacological use as an anti-DN agent.nnnMATERIALS AND METHODSnHepa 1c1c7 murine hepatoma cells, human breast carcinoma MDA-MB-231 cells, human renal glomerular endothelial cells (HRGEC), and RAW 264.7 murine macrophages were adopted to test the effects of EEL and its active constituents on inhibitions of oxidative stress and inflammation in vitro. A streptozotocin (STZ) -induced DN C57BL/6 mice model was established and used to investigate the preventive effect of EEL against DN in vivo.nnnRESULTSnEEL demonstrated potential inhibitory effects against oxidative stress and inflammation in vitro. Using a STZ-induced DN mice model, it has been found that EEL treatment significantly prevented STZ-induced increases of urine production, urinary albumin excretion (UAE) and urine albumin-to-creatinine ratio (UACR), and markedly attenuated STZ-induced renal damages (e.g. glomerulosclerosis and fibrosis). The predominant bioactive constituents, Z-ligustilide (LGT), ferulic acid (FA), and tetramethylpyrazine (TMP), were inhibitors of oxidative stress and inflammation through acting with Nrf2 and NF-κB pathways.nnnCONCLUSIONSnEEL attenuates structural and functional damages of kidney in STZ-induced DN model in vivo, which might be related to the functions of EEL on inhibitions of oxidative stress and inflammation. These finding definitely supports the ethnopharmacological use of LC as an anti-DN agent.

Botrysphones A–C and Botrysphins A–F, Triketides and Diterpenoids from the Fungus Botrysphaeria laricina

Three new triketides, botrysphones A-C (1-3) and six new isopimarane-type diterpenoids, botrysphins A-F (4-9), together with the known triketides sphaeropsidone (10) and chlorosphaeropsidone (11) and diterpenoids sphaeropsidins A and B (12 and 13), were obtained from culture of the fungus Botrysphaeria laricina associated with the moss Rhodobryum umgiganteum. The structures of the new compounds were established on the basis of extensive spectroscopic techniques including HRMS and 1D and 2D NMR data. Compounds 7 and 12 showed significant quinone reductase inducing activity in Hepa 1c1c7 cells.