Estrogens bind to two nuclear estrogen receptor (ER) subtypes, ERα and ERβ, which are expressed in differing amounts in various tissues. The endogenous estrogen, 17β-estradiol (E2), binds to both subtypes with nearly equal affinity and is the prototypical agonist. Selective estrogen receptor modulators (SERMs) may bind to both subtypes with equivalent affinities but have agonist activities in some tissues while having antagonist activities in others. In the present study, we demonstrate that the first reported endogenous SERM, 27-hydroxycholesterol (27-OHC), binds preferentially (>100-fold) to ERβ over ERα. Furthermore, 27-OHC is not able to fully compete with E2 binding, suggesting the two may bind at different sites. We provide an allosteric ternary complex model for the simultaneous binding of 27-OHC and E2 to ERβ, which accurately describes the binding data we have observed. We conclude that 27-OHC is a negative allosteric modifier of E2 binding, with an inhibitor constantof 50 nM and cooperativity factor (α) of 0.036. We also propose an in silico three-dimensional model of the simultaneous binding to guide future experiments. Further study of this unique binding model may allow for the discovery of novel ERβ-selective ligands and potentially explain the lack of effectiveness of ERβ-selective agonists in humans vs preclinical models.

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Sutherlandia frutescens is a medicinal plant traditionally used to treat various types of human diseases, including cancer. Previous studies of several botanicals link suppression of prostate cancer growth with inhibition of the Gli/hedgehog (Gli/Hh) signaling pathway. Here we hypothesized the anti-cancer effect of S. frutescens was linked to its inhibition of the Gli/Hh signaling in prostate cancer. We found a dose- and time- dependent growth inhibition in human prostate cancer cells PC3 and LNCaP, and mouse prostate cancer cells TRAMP-C2 treated with S. frutescens methanol extract (SLE). We also observed a dose-dependent inhibition of the Gli-reporter activity in Shh Light II and TRAMP-C2QGli cells treated with SLE. In addition, SLE can inhibit Gli/Hh signaling by blocking Gli1 and Ptched1 gene expression in the presence of a Gli/Hh signaling agonist (SAG). A diet supplemented with S. frutescens suppressed the formation of poorly differentiated carcinoma in prostates of TRAMP mice. Finally, we found Sutherlandioside D was the most potent compound in the crude extract that could suppress Gli-reporter in Shh Light II cells. Together this suggests that the S. frutescens extract may exert anti-cancer effect by targeting Gli/Hh signaling, and Sutherlandioside D is one of the active compounds.

Significance: Real-time information about oxygen delivery to the hepatic graft is important to direct care and diagnose vascular compromise in the immediate post-transplant period.Aim: The current study was designed to determine the utility of visible diffuse reflectance spectroscopy (vis-DRS) for measuring liver tissue saturation in vivo.Approach: A custom-built vis-DRS probe was calibrated using phantoms with hemoglobin (Hb) and polystyrene microspheres. Ex vivo (extracorporeal circulation) and in vivo protocols were used in a swine model (n ¼ 15) with validation via blood gas analysis.Results: In vivo absorption and scattering measured by vis-DRS with and without biliverdin correction correlated closely between analyses. Lin's concordance correlation coefficients are 0.991 for μ a and 0.959 for μ s 0 . Hb measured by blood test and vis-DRS with (R 2 ¼ 0.81) and without (R 2 ¼ 0.85) biliverdin correction were compared. Vis-DRS data obtained from the ex vivo protocol plotted against the PO 2 derived from blood gas analysis showed a good fit for a Hill coefficient of 1.67 and P 50 ¼ 34 mmHg (R 2 ¼ 0.81). A conversion formula was developed to account for the systematic deviation, which resulted in a goodness-of-fit R 2 ¼ 0.76 with the expected oxygen dissociation curve. Conclusions:We show that vis-DRS allows for real-time measurement of liver tissue saturation, an indicator for liver perfusion and oxygen delivery.

Sutherlandia frutescens (L) R. Br. (Sutherlandia) is a South African botanical that is traditionally used to treat a variety of health conditions, infections and diseases, including cancer. We hypothesized Sutherlandia might act through Gli/ Hedgehog (Hh)-signaling in prostate cancer cells and used RNA-Seq transcription profiling to profile gene expression in TRAMPC2 murine prostate cancer cells with or without Sutherlandia extracts. We found 50% of Hh-responsive genes can be repressed by Sutherlandia ethanol extract, including the canonical Hh-responsive genes Gli1 and Ptch1 as well as newly distinguished Hh-responsive genes Hsd11b1 and Penk.