Chrysophanic acid reduces testosterone-induced benign prostatic hyperplasia in rats by suppressing 5α-reductase and extracellular signal-regulated kinase.

Benign prostatic hyperplasia (BPH) is one of the most common chronic diseases in male population, of which incidence increases gradually with age. In this study, we investigated the effect of chrysophanic acid (CA) on BPH. BPH was induced by a 4-week injection of testosterone propionate (TP). Four weeks of further injection with vehicle, TP, TP + CA, TP + finasteride was carried on. In the CA treatment group, the prostate weight was reduced and the TP-induced histological changes were restored as the normal control group. CA treatment suppressed the TP-elevated prostate specific antigen (PSA) expression. In addition, 5α-reductase, a crucial factor in BPH development, was suppressed to the normal level close to the control group by CA treatment. The elevated expressions of androgen receptor (AR), estrogen receptor α and steroid receptor coactivator 1 by TP administration were also inhibited in the CA group when compared to the TP-induced BPH group. Then we evaluated the changes in three major factors of the mitogen-activated protein kinase chain during prostatic hyperplasia; extracellular signal-regulated kinase (ERK), c-Jun-N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38). While ERK was elevated in the process of BPH, JNK and p38 was not changed. This up-regulated ERK was also reduced as normal by CA treatment. Further in vitro studies with RWPE-1 cells confirmed TP-induced proliferation and elevated AR, PSA and p-ERK were all reduced by CA treatment. Overall, these results suggest a potential pharmaceutical feature of CA in the treatment of BPH.

3-Formylchromone inhibits proliferation and induces apoptosis of multiple myeloma cells by abrogating STAT3 signaling through the induction of PIAS3.

Constitutive activation of signal transducer and activator of transcription 3 (STAT3) is frequently observed and closely linked with proliferation, survival, metastasis and angiogenesis of various cancer cells, and thus its inhibition can be considered a potential therapeutic strategy. We found that 3-formylchromone (3FC) inhibited both constitutive and inducible STAT3 activation in multiple myeloma (MM) cells. Besides the inhibition of STAT3 phosphorylation, 3FC also abrogated constitutive activity and nuclear translocation of STAT3. This suppression was mediated through the inhibition of phosphorylation of Janus-activated kinase (JAK) 1/2 and Src. Furthermore, 3FC induced the expression of the protein inhibitors of activated STAT3 (PIAS3), and gene silencing of the PIAS3 by small interfering RNA abolished the ability of 3FC to inhibit STAT3 activation, suggesting a critical role for PIAS3 in the action of 3FC. 3FC also downregulated the expression of STAT3-regulated gene products such as Bcl-2, Bcl-xl, Mcl-1, Survivin, inhibitor of apoptosis protein-1 (IAP-1), Cyclin D1, cyclooxygenase-2 (COX-2), and matrix metalloproteinases-9 (MMP-9) in MM cells. This correlated with induction of substantial apoptosis as indicated by an increase in the sub-G1 cell population and caspase-3 induced poly ADP ribose polymerase (PARP) cleavage. Overall, these results suggest that 3FC is a novel blocker of STAT3 activation pathway thus may have a potential in therapy of MM and other cancers.

The aglycone of ginsenoside Rg3 enables glucagon-like peptide-1 secretion in enteroendocrine cells and alleviates hyperglycemia in type 2 diabetic mice.

Ginsenosides can be classified on the basis of the skeleton of their aglycones. Here, we hypothesized that the sugar moieties attached to the dammarane backbone enable binding of the ginsenosides to the sweet taste receptor, eliciting glucagon-like peptide-1 (GLP-1) secretion in the enteroendocrine L cells. Using the human enteroendocrine NCI-H716 cells, we demonstrated that 15 ginsenosides stimulate GLP-1 secretion according to the position of their sugar moieties. Through a pharmacological approach and RNA interference technique to inhibit the cellular signal cascade and using the Gαgust(-/-) mice, we elucidated that GLP-1 secreting effect of Rg3 mediated by the sweet taste receptor mediated the signaling pathway. Rg3, a ginsenoside metabolite that transformed the structure through a steaming process, showed the strongest GLP-1 secreting effects in NCI-H716 cells and also showed an anti-hyperglycemic effect on a type 2 diabetic mouse model through increased plasma GLP-1 and plasma insulin levels during an oral glucose tolerance test. Our study reveals a novel mechanism where the sugar moieties of ginsenosides Rg3 stimulates GLP-1 secretion in enteroendocrine L cells through a sweet taste receptor-mediated signal transduction pathway and thus has an anti-hyperglycemic effect on the type 2 diabetic mouse model.