RESUMO
Silibinin, extracted from milk thistle (Silybum marianum L.), has exhibited considerable preclinical activity against prostate carcinoma. Its antitumor and chemopreventive activities have been associated with diverse effects on cell cycle, apoptosis, and receptor-dependent mitogenic signaling pathways. Here we hypothesized that silibinin's pleiotropic effects may reflect its interference with epigenetic mechanisms in human prostate cancer cells. More specifically, we have demonstrated that silibinin reduces gene expression levels of the Polycomb Repressive Complex 2 (PRC2) members Enhancer of Zeste Homolog 2 (EZH2), Suppressor of Zeste Homolog 12 (SUZ12), and Embryonic Ectoderm Development (EED) in DU145 and PC3 human prostate cancer cells, as evidenced by Real Time Polymerase Chain Reaction (RT-PCR). Furthermore immunoblot and immunofluorescence analysis revealed that silibinin-mediated reduction of EZH2 levels was accompanied by an increase in trimethylation of histone H3 on lysine (Κ)-27 residue (H3K27me3) levels and that such response was, in part, dependent on decreased expression levels of phosphorylated Akt (ser473) (pAkt) and phosphorylated EZH2 (ser21) (pEZH2). Additionally silibinin exerted other epigenetic effects involving an increase in total DNA methyltransferase (DNMT) activity while it decreased histone deacetylases 1-2 (HDACs1-2) expression levels. We conclude that silibinin induces epigenetic alterations in human prostate cancer cells, suggesting that subsequent disruptions of central processes in chromatin conformation may account for some of its diverse anticancer effects.
Assuntos
Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Proteína Potenciadora do Homólogo 2 de Zeste/biossíntese , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Complexo Repressor Polycomb 2/biossíntese , Neoplasias da Próstata/tratamento farmacológico , Silimarina/farmacologia , Linhagem Celular Tumoral , DNA (Citosina-5-)-Metiltransferases , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Epigênese Genética , Histona Desacetilase 1/biossíntese , Histona Desacetilase 2/biossíntese , Histonas/metabolismo , Humanos , Masculino , Metilação/efeitos dos fármacos , Proteínas de Neoplasias , Fosforilação/efeitos dos fármacos , Complexo Repressor Polycomb 2/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Silibina , Fatores de TranscriçãoRESUMO
Spiroscytalin (1), a new tetramic acid that possesses an uncommon spiro-ring fusion between a polyketide-derived octalin ring system and a 2,4-pyrrolidinedione, along with two known compounds, leporin B (2) and purpactin A (3), were isolated from a solid phase culture of the fungus Scytalidium cuboideum (MSX 68345). The molecular connectivity of 1-3 was determined using NMR spectroscopy and mass spectrometry. The relative configurations of 1 and 2 were determined by NOESY experiments. The absolute configuration of 1 was determined by electronic circular dichroism (ECD) via a combination of experimental measurements and computational calculations. While leporin B was known, it displayed activities that had not been reported previously, including cytotoxicity against three human tumor cell lines and antibacterial activity against Candida albicans and Staphylococcus aureus.
RESUMO
An organic extract of a filamentous fungus (MSX 58801), identified as a Volutella sp. (Hypocreales, Ascomycota), displayed moderate cytotoxic activity against NCI-H460 human large cell lung carcinoma. Bioactivity-directed fractionation led to the isolation of three γ-lactones having the furo[3,4-b]pyran-5-one bicyclic ring system [waol A (1), trans-dihydrowaol A (2), and cis-dihydrowaol A (3)]. The structures were elucidated using a set of spectroscopic and spectrometric techniques; the absolute configuration of 2 was established via a modified Mosher's ester method. Compounds 1 and 2 were evaluated for cytotoxicity against a human cancer cell panel.
RESUMO
An extract of the filamentous fungus Bionectria sp. (MSX 47401) showed both promising cytotoxic activity (>90% inhibition of H460 cell growth at 20 µg/mL) and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). A bioactivity-directed fractionation study yielded one new peptaibol (1) and one new tetramic acid derivative (2), and the fungus biosynthesized diverse secondary metabolites with mannose-derived units. Five known compounds were also isolated: clonostachin (3), virgineone (4), virgineone aglycone (5), AGI-7 (6), and 5,6-dihydroxybisabolol (7). Compounds 5 and 7 have not been described previously from natural sources. Compound 1 represents the second member of the peptaibol structural class that contains an ester-linked sugar alcohol (mannitol) instead of an amide-linked amino alcohol, and peptaibols and tetramic acid derivatives have not been isolated previously from the same fungus. The structures of the new compounds were elucidated primarily by high-field NMR (950 and 700 MHz), HRESIMS/MS, and chemical degradations (Marfey's analysis). All compounds (except 6) were examined for antibacterial and antifungal activities. Compounds 2, 4, and 5 showed antimicrobial activity against S. aureus and several MRSA isolates.
Assuntos
Antibacterianos/isolamento & purificação , Antifúngicos/isolamento & purificação , Hypocreales/química , Isocumarinas/isolamento & purificação , Peptaibols/isolamento & purificação , Pirrolidinonas/isolamento & purificação , Sesquiterpenos/isolamento & purificação , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Glicosídeos/química , Glicosídeos/isolamento & purificação , Humanos , Isocumarinas/química , Isocumarinas/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Peptaibols/química , Peptaibols/farmacologia , Peptídeos/química , Peptídeos/isolamento & purificação , Pirrolidinonas/química , Pirrolidinonas/farmacologia , Sesquiterpenos/química , Sesquiterpenos/farmacologiaRESUMO
Three bioactive compounds were isolated from an organic extract of an ascomycete fungus of the order Chaetothyriales (MSX 47445) using bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi. Of these, two were benzoquinones [betulinan A (1) and betulinan C (3)], and the third was a terphenyl compound, BTH-II0204-207:A (2). The structures were elucidated using a set of spectroscopic and spectrometric techniques; the structure of the new compound (3) was confirmed via single-crystal X-ray diffraction. Compounds 1-3 were evaluated for cytotoxicity against a human cancer cell panel, for antimicrobial activity against Staphylococcus aureus and Candida albicans, and for phosphodiesterase (PDE4B2) inhibitory activities. The putative binding mode of 1-3 with PDE4B2 was examined using a validated docking protocol, and the binding and enzyme inhibitory activities were correlated.
Assuntos
Ascomicetos/química , Benzoquinonas/isolamento & purificação , Benzoquinonas/farmacologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/efeitos dos fármacos , Inibidores da Fosfodiesterase 4/isolamento & purificação , Inibidores da Fosfodiesterase 4/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Compostos de Terfenil/isolamento & purificação , Compostos de Terfenil/farmacologia , Ascomicetos/classificação , Benzoquinonas/química , Candida albicans/efeitos dos fármacos , Cristalografia por Raios X , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Inibidores da Fosfodiesterase 4/química , Compostos de Terfenil/químicaRESUMO
Flavonolignans from milk thistle (Silybum marianum) have been investigated for their cellular modulatory properties, including cancer chemoprevention and hepatoprotection, as an extract (silymarin), as partially purified mixtures (silibinin and isosilibinin), and as pure compounds (a series of seven isomers). One challenge with the use of these compounds in vivo is their relatively short half-life due to conjugation, particularly glucuronidation. In an attempt to generate analogues with improved in vivo properties, particularly reduced metabolic liability, a semi-synthetic series was prepared in which the hydroxy groups of silybin B were alkylated. A total of five methylated analogues of silybin B were synthesized using standard alkylation conditions (dimethyl sulfate and potassium carbonate in acetone), purified using preparative HPLC, and elucidated via spectroscopy and spectrometry. Of the five, one was monomethylated (3), one was dimethylated (4), two were trimethylated (2 and 6), and one was tetramethylated (5). The relative potency of all compounds was determined in a 72 h growth-inhibition assay against a panel of three prostate cancer cell lines (DU-145, PC-3, and LNCaP) and a human hepatoma cell line (Huh7.5.1) and compared to natural silybin B. Compounds also were evaluated for inhibition of both cytochrome P450 2C9 (CYP2C9) activity in human liver microsomes and hepatitis C virus infection in Huh7.5.1 cells. The monomethyl and dimethyl analogues were shown to have enhanced activity in terms of cytotoxicity, CYP2C9 inhibitory potency, and antiviral activity (up to 6-fold increased potency) compared to the parent compound, silybin B. In total, these data suggested that methylation of flavonolignans can increase bioactivity.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Antivirais/farmacologia , Hidrocarboneto de Aril Hidroxilases/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Hepacivirus/efeitos dos fármacos , Silimarina/farmacologia , Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/química , Antivirais/síntese química , Antivirais/química , Hidrocarboneto de Aril Hidroxilases/metabolismo , Proliferação de Células/efeitos dos fármacos , Citocromo P-450 CYP2C9 , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Metilação , Testes de Sensibilidade Microbiana , Microssomos Hepáticos/enzimologia , Estrutura Molecular , Silibina , Silimarina/síntese química , Silimarina/química , Relação Estrutura-AtividadeRESUMO
The hollow fiber assay (HFA) is a drug discovery tool to aid investigators in the prioritization of lead compounds identified by in vitro testing for further development in animal models of disease. In the HFA, cells are cultured in hollow fibers containing pores of a diameter (500 kDa) large enough for proteins and other macromolecules to enter, but too small for the cells to escape. The fibers are filled with cells, sealed and placed in the peritoneal cavity of immunodeficient mice. The mice undergo a predetermined treatment regimen after which the fibers are retrieved and the cells evaluated for activity of a target relevant to the disease modeled. The HFA combines advantages of both in vitro and in vivo assay systems. It uses the same cell lines used in culture systems, is a rapid assay, and requires fewer animals and less test substance than conventional xenograft systems. Like traditional in vivo assays, the test substance is evaluated in a live animal, which affords an initial assessment of associated toxicity and pharmacokinetic properties of the test substance.
Assuntos
Antineoplásicos/farmacologia , Produtos Biológicos/farmacologia , Descoberta de Drogas/instrumentação , Animais , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Feminino , CamundongosRESUMO
Bioactivity-directed fractionation of the organic extracts of two filamentous fungi of the Bionectriaceae, strains MSX 64546 and MSX 59553 from the Mycosynthetix library, led to the isolation of a new dimeric epipolythiodioxopiperazine alkaloid, verticillin H (1), along with six related analogs, Sch 52900 (2), verticillin A (3), gliocladicillin C (4), Sch 52901 (5), 11'-deoxyverticillin A (6) and gliocladicillin A (7). The structures of compounds 1-7 were determined by extensive NMR and HRMS analyses, as well as by comparisons to the literature. All compounds (1-7) were evaluated for cytotoxicity against a panel of human cancer cell lines, displaying IC(50) values ranging from 1.2 µM to 10 nM. Compounds 1-5 were examined for activity in the NF-κB assay, where compounds 2 and 3 revealed activity in the sub-micromolar range. Additionally, compounds 1, 3 and 4 were tested for EGFR inhibition using an enzymatic assay, while compound 3 was examined against an overexpressing EGFR(+ve) cancer cell line.
Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Dissulfetos/isolamento & purificação , Dissulfetos/farmacologia , Hypocreales/química , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/farmacologia , Piperazinas/isolamento & purificação , Piperazinas/farmacologia , Compostos de Terfenil/isolamento & purificação , Compostos de Terfenil/farmacologia , Antibióticos Antineoplásicos/química , Antibióticos Antineoplásicos/isolamento & purificação , Antibióticos Antineoplásicos/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Dissulfetos/química , Ensaios de Seleção de Medicamentos Antitumorais , Receptores ErbB/antagonistas & inibidores , Humanos , Alcaloides Indólicos/química , Indóis/química , Indóis/isolamento & purificação , Indóis/farmacologia , Espectroscopia de Ressonância Magnética , Estrutura Molecular , NF-kappa B/antagonistas & inibidores , Piperazinas/química , Compostos de Terfenil/químicaRESUMO
Chemical investigation of two cultured cyanobacteria, Westiellopsis sp. (SAG strain number 20.93) and Fischerella muscicola (UTEX strain number LB1829) led to the isolation of three hapalindole-type alkaloids, namely hapalindole X (1), deschloro hapalindole I (2), and 13-hydroxy dechlorofontonamide (3), along with ten known indole alkaloids (hapalindoles A, C, G, H, I, J, and U, hapalonamide H, anhydrohapaloxindole A, and fischerindole L) and fischerellins A and B. The structures were determined by a combination of spectroscopic analyses mainly based on 1D and 2D NMR and HRESIMS data. Selected compounds were evaluated for cytotoxicity and exhibited weak to moderate cytotoxicity against HT-29, MCF-7, NCI-H460, SF268, and IMR90 cells. All compounds, except hapalindole C, were evaluated for 20S proteasome inhibition and displayed either weak or no inhibition at 25 µg/mL. Selected compounds were also evaluated for antimicrobial activity, and hapalindoles X (1) and A, and hapalonamide H showed potent activity against both Mycobacterium tuberculosis and Candida albicans with MIC values ranging from 0.6 to 2.5 µM.
Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Cianobactérias/química , Alcaloides Indólicos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antifúngicos/química , Antifúngicos/isolamento & purificação , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Candida albicans/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Alcaloides Indólicos/química , Alcaloides Indólicos/isolamento & purificação , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
As part of an ongoing investigation of filamentous fungi for anticancer leads, an active culture was identified from the Mycosynthetix library (MSX 70741, of the order Hypocreales, Ascomycota). The fungal extract exhibited cytotoxic activity against the H460 (human nonsmall cell lung carcinoma) cell line, and bioactivity-directed fractionation yielded peptaibols 1-12 and harzianums A (13) and B (14). Structure elucidation of 1-12 was facilitated by high-resolution MS/MS using higher-energy collisional dissociation and by high field NMR (950 MHz). The absolute configuration was determined by Marfey's analysis of the individual amino acids; the time required for such analysis was decreased via the development of a 10-min ultra performance liquid chromatography method. The isolated peptaibols (1-12), along with three other peptaibols isolated and elucidated from a different fungus (MSX 57715) of the same order (15-17), were examined for activity in a suite of biological assays, including those for cytotoxic, antibacterial, and anthelmintic activities.
Assuntos
Anti-Helmínticos/farmacologia , Antibacterianos/farmacologia , Hypocreales/química , Peptaibols/química , Peptaibols/farmacologia , Animais , Anti-Helmínticos/química , Antibacterianos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Haemonchus/efeitos dos fármacos , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Ressonância Magnética Nuclear BiomolecularRESUMO
Chemical investigation of the cultured cyanobacterium Fischerella sp. (SAG strain number 46.79) led to the isolation of four nitrile-containing indole alkaloids, namely 12-epi-fischerindole I nitrile (1), deschloro 12-epi-fischerindole I nitrile (2), 12-epi-fischerindole W nitrile (3), and deschloro 12-epi-fischerindole W nitrile (4) along with a known metabolite hapalosin. The structures were determined by detailed spectroscopic analyses on the basis of 1D and 2D NMR and HRESIMS data. All isolates were evaluated for cytotoxicity against human cancer cells and for 20S proteasome inhibition. Deschloro 12-epi-fischerindole I nitrile (2) was found to be weakly cytotoxic against HT-29 cells with an ED(50) value of 23 µM. Hapalosin showed weak cytotoxicity against HT-29 and MCF-7 cells with ED(50) values of 22 and 27 µM, respectively, as well as moderate 20S proteasome inhibition with an IC(50) value of 12 µM. Compounds 1-4 all contain a nitrile moiety instead of the isonitrile found in all fischerindoles reported to date. Compounds 3 and 4 also display a new carbon skeleton, in which a six-membered ring replaces the five-membered ring normally found in fischerindole-type alkaloids.
RESUMO
Two new xanthone-anthraquinone heterodimers, acremoxanthone C (5) and acremoxanthone D (2), have been isolated from an extract of an unidentified fungus of the order Hypocreales (MSX 17022) by bioactivity-directed fractionation as part of a search for anticancer leads from filamentous fungi. Two known related compounds, acremonidin A (4) and acremonidin C (3) were also isolated, as was a known benzophenone, moniliphenone (1). The structures of these isolates were determined via extensive use of spectroscopic and spectrometric tools in conjunction with comparisons to the literature. All compounds (1-5) were evaluated against a suite of biological assays, including those for cytotoxicity, inhibition of the 20S proteasome, mitochondrial transmembrane potential and nuclear factor-κB.
Assuntos
Antraquinonas/isolamento & purificação , Antraquinonas/farmacologia , Antineoplásicos/isolamento & purificação , Hypocreales/química , Xantonas/isolamento & purificação , Xantonas/farmacologia , Antraquinonas/química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Estrutura Molecular , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , Ressonância Magnética Nuclear Biomolecular , Rotação Ocular , Complexo de Endopeptidases do Proteassoma/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Xantonas/químicaRESUMO
Two new cyclodepsipeptides (1 and 2), two new sesquiterpenoids (3 and 4), and the known compounds guangomide A (5), roseotoxin S, and three simple trichothecenes were isolated from the cytotoxic organic extract of a terrestrial filamentous fungus, Trichothecium sp. The structures were determined using NMR spectroscopy and mass spectrometry. Absolute configurations of the cyclodepsipeptides were established by employing chiral HPLC, while the relative configurations of 3 and 4 were determined via NOESY data. The isolation of guangomide A was of particular interest, since it was reported previously from a marine-derived fungus.
Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Depsipeptídeos/isolamento & purificação , Depsipeptídeos/farmacologia , Fungos/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Antineoplásicos/química , Cromatografia Líquida de Alta Pressão , Depsipeptídeos/química , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Sesquiterpenos/química , Tricotecenos/química , Tricotecenos/isolamento & purificação , Tricotecenos/farmacologiaRESUMO
A fungal extract (MSX 63619), from the Mycosynthetix library of over 50,000 fungi, displayed promising cytotoxicity against a human tumor cell panel. Bioactivity-directed fractionation led to the isolation of an o-pyranonaphthoquinone decaketide, which we termed obionin B (1). The structure of 1 was deduced via spectroscopic and spectrometric techniques. The IC(50) value of 1 was moderate, ranging from 3 to 13 µM, depending on the cell line tested.
RESUMO
As part of our ongoing investigation of filamentous fungi for anticancer leads, an active fungal extract was identified from the Mycosynthetix library (MSX 63935; related to Phoma sp.). The initial extract exhibited cytotoxic activity against the H460 (human non-small cell lung carcinoma) and SF268 (human astrocytoma) cell lines and was selected for further study. Bioactivity-directed fractionation yielded resorcylic acid lactones (RALs) 1 (a new natural product) and 3 (a new compound) and the known RALs zeaenol (2), (5E)-7-oxozeaenol (4), (5Z)-7-oxozeaenol (5), and LL-Z1640-1 (6). Reduction of (5E)-7-oxozeaenol (4) with sodium borohydride produced 3, which allowed assignment of the absolute configuration of 3. Other known resorcylic acid lactones (7-12) were purchased and assayed in parallel for cytotoxicity with isolated 1-6 to investigate structure-activity relationships in the series. Moreover, the isolated compounds (1-6) were examined for activity in a suite of biological assays, including antibacterial, mitochondria transmembrane potential, and NF-κB. In the latter assay, compounds 1 and 5 displayed sub-micromolar activities that were on par with the positive control, and as such, these compounds may serve as a lead scaffold for future medicinal chemistry studies.
Assuntos
Lactonas/isolamento & purificação , Lactonas/farmacologia , NF-kappa B/antagonistas & inibidores , Zearalenona/análogos & derivados , Antibacterianos/farmacologia , Fungos/química , Humanos , Hidroxibenzoatos/química , Lactonas/química , Estrutura Molecular , Resorcinóis , Relação Estrutura-Atividade , Zearalenona/química , Zearalenona/farmacologiaRESUMO
As part of our ongoing investigation of filamentous fungi for anticancer leads, an active fungal extract was identified from the Mycosynthetix library (MSX 55526; from the Order Sordariales). Bioactivity-directed fractionation yielded the known ergosterol peroxide (2) and 5α,8α-epidioxyergosta-6,9(11),22-trien-3ß-ol(3), and a new benzoate trimer, termed thielavin B methyl ester (1). The structure elucidation of 1 was facilitated by the use of HRMS coupled to an APPI (atmospheric pressure photoionization) source. Compound 1 proved to be moderately active against a panel of three cancer cell lines.
RESUMO
BACKGROUND: Cranberry products have been implicated in several case reports to enhance the anticoagulant effect of warfarin. The mechanism could involve inhibition of the hepatic CYP2C9-mediated metabolic clearance of warfarin by components in cranberry. Because dietary/natural substances vary substantially in bioactive ingredient composition, multiple cranberry products were evaluated in vitro before testing this hypothesis in vivo. METHODS: The inhibitory effects of five types of cranberry juices were compared with those of water on CYP2C9 activity (S-warfarin 7-hydroxylation) in human liver microsomes (HLM). The most potent juice was compared with water on S/R-warfarin pharmacokinetics in 16 healthy participants given a single dose of warfarin 10 mg. RESULTS: Only one juice inhibited S-warfarin 7-hydroxylation in HLM in a concentration-dependent manner (P < 0.05), from 20% to >95% at 0.05% to 0.5% juice (v/v), respectively. However, this juice had no effect on the geometric mean AUC(0-∞) and terminal half-life of S/R-warfarin in human subjects. CONCLUSIONS: A cranberry juice that inhibited warfarin metabolism in HLM had no effect on warfarin clearance in healthy participants. The lack of an in vitro-in vivo concordance likely reflects the fact that the site of warfarin metabolism (liver) is remote from the site of exposure to the inhibitory components in the cranberry juice (intestine).
RESUMO
Prostate cancer (PCA) is the second most malignancy in American men. Advanced stage PCA cells possess unlimited replication potential as well as resistance to apoptosis. Therefore, targeting survival mechanisms and activating apoptotic machinery in PCA cells using nontoxic phytochemicals is suggested as an attractive strategy against this deadly malignancy. In the present study, we assessed the effect of one such botanical agent, namely isosilybin A, on apoptotic machinery and key members of cell survival signaling [Akt, NF-κB, and androgen receptor (AR)] in different PCA cells. Results showed that isosilybin A (90-180 µM) treatment significantly induces apoptotic death by activating both extrinsic (increased level of DR5 and cleaved caspase 8) and intrinsic pathways (caspase 9 and 3 activation) of apoptosis in three different human PCA cell lines namely 22Rv1, LAPC4, and LNCaP. Further, isosilybin A treatment decreased the levels of phospho-Akt (serine-473), total Akt, and the nuclear levels of NF-κB constituents (p50 and p65). Isosilybin A treatment also decreased the AR and PSA level in 22Rv1, LAPC4, and LNCaP cells. Employing pan-caspase inhibitor (Z-VAD.fmk), we confirmed that isosilybin A-mediated decreased AR is independent of caspases activation. Temporal kinetics analysis showed that the primary effect of isosilybin A is on AR, as decrease in AR was evident much earlier (4 h) relative to caspase activation and apoptosis induction (12 h). Overall, our results demonstrated that isosilybin A activates apoptotic machinery in PCA cells via targeting Akt-NF-κB-AR axis; thereby, indicating a promising role for this phytochemical in the management of clinical PCA.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , NF-kappa B/metabolismo , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Androgênicos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Silimarina/análogos & derivados , Apoptose/fisiologia , Caspase 8/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Núcleo Celular/patologia , Humanos , Masculino , NF-kappa B/antagonistas & inibidores , NF-kappa B/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Silimarina/farmacologia , Fator de Transcrição RelA/metabolismo , Fator de Transcrição RelA/farmacologia , Fator de Transcrição RelA/uso terapêuticoRESUMO
Macrocyclic trichothecenes (MTs), which have potent cytotoxicity, have been isolated from many different fungal species. These compounds were evaluated clinically by the US National Cancer Institute in the 1970s and 1980s. However, they have yet to be advanced into viable drugs because of severe side effects. Our team is investigating a diverse library of filamentous fungi for new anticancer leads. To avoid reisolating MTs through bioactivity-directed fractionation studies, a protocol for their facile dereplication was developed. The method uses readily available photodiode array detectors to identify one of two types of characteristic UV spectra for these compounds. In addition, diagnostic signals can be observed in the (1)H-NMR spectra, particularly for the epoxide and conjugated diene moieties, even at the level of a crude extract. Using these techniques in a complementary manner, MTs can be dereplicated rapidly.
Assuntos
Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Compostos Macrocíclicos/química , Compostos Macrocíclicos/isolamento & purificação , Tricotecenos/química , Tricotecenos/isolamento & purificação , Linhagem Celular Tumoral , Fungos/química , Humanos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Espectrofotometria UltravioletaRESUMO
A new colchicinoid from Colchicum crocifolium Boiss. (Colchicaceae) was isolated and identified as N,N-dimethyl-N-deacetyl-(-)-cornigerine (5), along with four known compounds, but new to the species: (-)-colchicine (1), (-)-demecolcine (2), (-)-N-methyl-(-)-demecolcine (3) and 3-demethyl-N-methyl-(-)-demecolcine (4). All isolated compounds showed potent cytotoxicity against a human cancer cell panel.