Potential signaling pathways induced by lignans.

<p>Potential signaling pathways induced by lignans.</p

Differential regulation of cell cycle by lignans.

<p>MCF-7 cells were treated with vehicle (<b>A</b>) or 10 nM E₂ (<b>C</b>), or 10 μM each of lignans (<b>E</b>, <b>G</b>, <b>I</b>, <b>K</b>, and <b>M</b>) for the indicated times. Cell extracts were subjected to Western blot analysis for cyclin D1, CDK4, cyclin E and β-actin (control). The results of three independent experiments are summarized along with the statistical evaluation in panels <b>D</b> (for E₂), and <b>F</b>, <b>H</b>, <b>J</b>, <b>L</b> and <b>N</b> (for lignans). Statistical significance of data compared with the negative control (lane 1) is shown as * (<i>p</i> < 0.05).</p

Differential and directional estrogenic signaling pathways induced by enterolignans and their precursors

<div><p>Mammalian lignans or enterolignans are metabolites of plant lignans, an important category of phytochemicals. Although they are known to be associated with estrogenic activity, cell signaling pathways leading to specific cell functions, and especially the differences among lignans, have not been explored. We examined the estrogenic activity of enterolignans and their precursor plant lignans and cell signaling pathways for some cell functions, cell cycle and chemokine secretion. We used DNA microarray-based gene expression profiling in human breast cancer MCF-7 cells to examine the similarities, as well as the differences, among enterolignans, enterolactone and enterodiol, and their precursors, matairesinol, pinoresinol and sesamin. The profiles showed moderate to high levels of correlation (<i>R</i> values: 0.44 to 0.81) with that of estrogen (17β-estradiol or E₂). Significant correlations were observed among lignans (<i>R</i> values: 0.77 to 0.97), and the correlations were higher for cell functions related to enzymes, signaling, proliferation and transport. All the enterolignans/precursors examined showed activation of the Erk1/2 and PI3K/Akt pathways, indicating the involvement of rapid signaling through the non-genomic estrogen signaling pathway. However, when their effects on specific cell functions, cell cycle progression and chemokine (MCP-1) secretion were examined, positive effects were observed only for enterolactone, suggesting that signals are given in certain directions at a position closer to cell functions. We hypothesized that, while estrogen signaling is initiated by the enterolignans/precursors examined, their signals are differentially and directionally modulated later in the pathways, resulting in the differences at the cell function level.</p></div

Secretion of MCP-1 in response to stimulation with lignans.

<p>MCF-7 cells were treated with E₂ (10 nM) or each of the lignans (10 μM) for 72 h in the presence or absence of ICI 182,780 (ICI). Then, the supernatants were collected and ELISA was performed according to the manufacturer's instructions. The data represent the mean ± SD of three independent experiments. *: <i>p</i> < 0.05; vs. control (C), or #: <i>p</i> < 0.05; vs. ICI 182,780 (-).</p

Differential and directional estrogenic signaling pathways induced by enterolignans and their precursors - Fig 1

<p><b>Chemical structure (A) and cell-proliferation assay (B) for lignans.</b> (<b>A</b>) The phenylpropane backbone is shadowed. (<b>B</b>) MCF-7 cells were treated with vehicle (dimethylsulfoxide, DMSO), E₂ (10 nM) or different concentrations of chemicals as indicated: 1, 1 nM; 2, 10 nM; 3, 100 nM; 4, 1 μM; 5, 10 μM; and 6, 100 μM (on the left), and 10 μM EL (on the right). After incubation for 72 h, cell proliferation was examined by sulforhodamine B (SRB) assay. The rates of cell proliferation in response to E₂ or lignans to that of a control (DMSO) are shown in the graph. *: <i>p</i> < 0.05; vs. control (C), #: <i>p</i> < 0.05; vs. E₂, or §: <i>p</i> < 0.05; vs. EL. ICI: ICI 182,780, an ER antagonist.</p

Western-blot analysis of Erk1/2 and Akt signaling pathways induced by lignans.

<p>Active/total Erk1/2 and Akt were analyzed by Western blotting. MCF-7 cells were treated with 10 nM E₂ (<b>A</b>) or 10 μM each of lignans (<b>C</b>, <b>E</b>, <b>G</b>, <b>I</b>, and <b>K</b>) in the presence or absence of inhibitors, ICI 182,780 (ICI) or LY294002 (LY), for the indicated times (minutes), and cell extracts were subjected to Western blot analysis for phosphorylated (P-) or total (T-) proteins as indicated. The results of three independent experiments are summarized along with the statistical evaluation in panels <b>B</b> (for E₂), and <b>D</b>, <b>F</b>, <b>H</b>, <b>J</b>, and <b>L</b> (for lignans). Statistical significance of data compared with the negative (lane 1) or positive (lanes 3) controls is shown as * (<i>p</i> < 0.05; vs. lane 1) or § (<i>p</i> < 0.05; vs. lane 3).</p

Estrogenic gene expression profiles of lignans revealed by DNA microarray assay.

<p>Correlation of gene expression profiles was examined between individual pairs of E₂ and lignans. The gene expression profiles for these chemicals were compared using a set of 150 estrogen-responsive genes in scatter-plot graphs. The vertical and horizontal axes indicate log₂ values of the signal intensities. <i>R</i>- and <i>p</i>-values were calculated for each graph on the basis of linear regression between two profiles.</p

Additional file 1: of Silibinin efficacy in a rat model of pulmonary arterial hypertension using monocrotaline and chronic hypoxia

Table S1. Primers used for RT-qPCR. Table S2. The p value of two-way ANOVA analysis. Figure S1. Measurement of RVSP in different groups. Figure S2. The results of two-way ANOVA analysis. Figure S3. Hemodynamic studies, immunohistochemical evaluation, and gene expression of PAH-5w and Sil-5w groups. (ZIP 6575 kb