Inhibition of SRC-1 expression in prostate cancer cells by RNAi and its significance / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the inhibition of the expression of steroid receptor coactivator-1 (SRC-1) in the LNCap cell line through RNA interference (RNAi) and the effect of the silenced SRC-1 gene on LNCap cells.</p><p><b>METHODS</b>The experiment included four groups: siRNA transfection, siRNA negative control, bland vehicle (with Lipofectamine 2000 but no siRNA), and blank control (with neither Lipofectamine 2000 nor siRNA). LNCap cells were transfected with designed siRNA using the liposomes method, the expressions of SRC-1 determined by Q-PCR and Western blot, and the proliferation of the LNCap cells detected by the CCK-8 method.</p><p><b>RESULTS</b>The expression of SRC-1 mRNA in the transfected LNCap cells was decreased by 35% at 24 hours and 77% at 48 hours, with statistically significant differences from the blank control group (P < 0.05). The SRC-1 protein expression of the transfected group was 0.359 +/- 0.034 at 24 hours and 0.257 +/- 0.065 at 48 hours, markedly decreased as compared with that of the negative control (0.782 +/- 0.078 and 0.766 +/- 0.043) , bland vehicle (0.840 +/- 0.013 and 0.786 +/- 0.051), and blank control group (0.816 +/- 0.065 and 0.805 +/- 0.107) (P < 0.05). The LNCap cell growth inhibition rates were 25%, 52%, 55% and 60% at 24, 48, 72 and 96 hours, respectively.</p><p><b>CONCLUSION</b>The expression of SRC-1 is correlated with the growth of LNCap cells; its high expression in androgen-independent prostate cancer cells may be involved in the progression to androgen-independence. Inhibiting the expression of SRC-1 may be an option for the treatment of androgen-dependent prostate cancer.</p>

Differential binding with ERá and ERâ of the phytoestrogen-rich plant Pueraria mirifica

Variations in the estrogenic activity of the phytoestrogen-rich plant, Pueraria mirifica, were determined with yeast estrogen screen (YES) consisting of human estrogen receptors (hER) hERá and hERâ and human transcriptional intermediary factor 2 (hTIF2) or human steroid receptor coactivator 1 (hSRC1), respectively, together with the â-galactosidase expression cassette. Relative estrogenic potency was expressed by determining the â-galactosidase activity (EC50) of the tuber extracts in relation to 17â-estradiol. Twenty-four and 22 of the plant tuber ethanolic extracts interacted with hERá and hERâ, respectively, with a higher relative estrogenic potency with hERâ than with hERá. Antiestrogenic activity of the plant extracts was also determined by incubation of plant extracts with 17â-estradiol prior to YES assay. The plant extracts tested exhibited antiestrogenic activity. Both the estrogenic and the antiestrogenic activity of the tuber extracts were metabolically activated with the rat liver S9-fraction prior to the assay indicating the positive influence of liver enzymes. Correlation analysis between estrogenic potency and the five major isoflavonoid contents within the previously HPLC-analyzed tuberous samples namely puerarin, daidzin, genistin, daidzein, and genistein revealed a negative result.

Coexpression of PXRLBD with SRC88 and construction of equilibrium dialysis model of screening PXR ligands / 药学学报

The aim of this study was to obtain the soluble protein of human pregnane X receptor ligand binding domain (PXRLBD) through the coexpression of PXRLBD and 88 amino acids of steroid receptor coactivator-1 (SRC88) and apply the protein to constructing a new model of screening PXR ligands. Expression plasmid of pETDuet-1-SRC88-PXRLBD was constructed and transformed into Escherichia coli Rosetta (DE3) to coexpress PXRLBD and SRC88 via induction by IPTG at low temperature. Then an equilibrium dialysis model was constructed to study the interaction between PXRLBD and drugs including clotrimazole and dexamethasone, using HPLC as the analysis method. The results showed that the soluble protein of PXRLBD was obtained and the HPLC data indicated that clotrimazole bound to PXRLBD, while dexamethasone did not bind to PXRLBD, which indicated the successful establishment of a new method for studying the interaction between PXR and drugs. The new method may be useful in the screening of PXR ligands in vitro.