Group items tagged

Great article!!  Nice discussion of the complexity of hormones.  Women on aromatase inhibitors can make estrogen from Testosterone.  This is important with estrogen sensitive cancer as in breast cancer.  This will occur via alternative pathways: Testosterone to DHT via 5 alpha reductase and then DHT to 3 beta androstanediol via 3 beta HSD.  3 beta androstanediol is a male hormone metabolite that binds to estrogen receptors.  The affinity is less than Estradiol, but appears to have a higher affinity for ER beta over ER alpha. 

ER beta plays an important role in the prostate.  Loss of ER beta expression in the prostate has been shown to promote carcinogenesis.  In addition, 3-beta androstanediol, a DHT metabolite has been shown to signal through ER beta.

Estrogen receptors alpha and beta show dominance in the proliferative phases, with alpha isoform predominating.  In the secretory phase, less expression of ER was present. ER alpha was predominantly expressed in the epithelial and stromal cells in the proliferative phase.  ER beta was predominantly expressed in glandular cells in the same proliferative phase.   in the luteal phase, ER alpha expression declined in the funtionalis layers.  ER alpha in the basalis remained unchanged.  ER beta in the functionalis layers also declined in the luteal phase.   No relative change was found in the weak expression of ER alpha/beta in the myometrium.

3-beta androstanediola, a product of 3alpha-HSD from DHT binds to ER beta and down regulates AR in prostate cancer.  This study proposes that the mechanism is via CYP7B1.  CYP7B1 inactivates 3-beta androstanediol.  Interesting, because 3-beta androstanediol is considered "inactive" when compared to 3-alpha androstanediol and its interaction with ER alpha.  

ER-beta found throughout both the proliferative and secretory phases of the menstrual cycle.  ER-beta expression was higher in the proliferative versus the secretory phases, though not statistically significant.  This makes since as estrogen stimulation dominates the proliferative phase.  Additionally, ER-beta expression was found throughout all levels of the endometrium and the myometrium.

Loss of ER beta associated with higher risk of colon cancer.  ER beta has been shown to be highly expressed in health colons.  It has been proposed that loss of this ER beta expression is associated with carcinogenesis.

Studies in breast cancer and prostate cancer have revealed different effects by ER alpha vs ER beta.  It is no surprise that the same effects are found in ovarian cancer.  This study found ER alpha antagonists and ER beta agonists "significantly" suppressed growth in the ovarian cancer cell lines SKOV3 and OV2008.  Also, ER alpha agonist and ER beta antagonist "significantly" increased growth in the same cell lines.  These findings point to in increased proliferation with ER alpha and decreased with ER beta.  This is consistent with breast and prostate cancer also.

Estrogen Receptor Beta shown to inhibit growth and spread of breast cancer cells.  So, ER-beta should be evaluated to not only prevent/slow the growth of breast cancer, but to prevent the spread of breast cancer.  This study proposes that the loss of ER-beta is a seminal event in the development of breast cancer.

ER beta and prostate cancer.  More aggressive prostate cancer is found to be associated with lower ER beta expression in the prostate.  this makes sense, as other studies have shown that ER beta in the prostate can induce apoptosis (cell death), which is a powerful mechanism to regulate uncontrolled growth as found in cancer.

another awesome article dealing with hormone metabolites. Physicians that don't understand metabolites and receptors may be doing more harm than good.   One of the mainstays of the treatment of metastatic prostate disease is androgen deprivation therapy.  This article requires a reassessment of this due to the DHT metabolite 3-beta androstanediol.  This metabolite is produced from DHT production via the enzyme 3beta HSD.  This metabolite binds to ER beta, an estrogen receptor, and inhibits proliferation, migration, promotes adhesion (limits spreading), and stimulates apoptosis.  This is contrast to 3-alpha androstanediol.  Androgen deprivation therapy will decrease 3-beta androstanediol.  This is the likely reason for the increased aggressive prostate cancer found in those men using 5 alpha reductase inhibitors.

The process of androgen deprivation therapy needs to be re-evaluated.  Why?  First, the CVD side effects associated with the androgen depletion.  Second, the depletion of 3 beta androstanediol that has been shown to bind to ER beta and inhibit growth.  As in this study that finds that ER beta activity slows prostate cancer through destabilizing of HIF-1 alpha and by inhibiting VEGF.

ER beta expression is dominant in healthy colon epithelium.  This study found that as colon disease progressed, ER beta expression declined.  So that, early disease was associated with the highest level of ER beta expression.

ER-beta inhibits ER-alpha activation of cell proliferation via cyclin D1 gene expression.  This points to ER-beta as a counter regulatory receptor to ER-alpha.  This explains how a loss of ER-beta expression is found to be associated with increased cancers.  

Study shows that estradiol decreases ER beta in the prostate. ER beta is anti-inflammatory, inhibits growth, and promotes cell death: all of which would decrease risk of prostate growth and/or cancer.   We know that men increase estrogen production through increased aromatase activity, which according to this study, will decrease ER beta and the prostate associated benefits.

Great article on ER beta and the prostate.  ER alpha expression is very important in the development of the prostate.  IN that instance, ER beta is down regulated.  In prostate cancer generation, ER beta expression in the epithelium is lost.

ER beta expression that is lost in prostate carcinogenesis occurs via methylation at the ER beta gene promoter sites 19CpG.  What is really interesting is that ER beta expression was present in all of the samples with BPH, but was absent in 83% of the prostate cancer samples.

5-beta androstanediol doesn't have affinity for androgen receptors, but for estrogen receptors. Affinity for ER beta exceeds that for ER alpha.

Additional support for ER beta role in protection in colon cancer.  This study found that SNPs in ER beta transcription resulted in reduced ER beta expression and a resultant increase in carcinogenesis.

ER beta expression is dominantly expressed in normal, healthy colon cells/tissue.  However, like in breast and prostate cancer, ER beta expression is lost in the dedifferentiation of colorectal transformation.

ER-beta expression appears to regulate estrogenic activity through ER-alpha expression.  Co-expression of ER-alpha and ER-beta is associated with reduced estrogenic signaling, indicating a significant counter regulatory role for ER-beta.