Dr. Ron’s Research Review – October 27, 2010

This week’s research review contains articles on Estrogen receptors and androstanediol; Mitochondrial dysfunction; and Atlas vertebra realignment to lower blood pressure.

Androstanediol and Prostate Cancer

In the prostate, ER-beta is highly expressed in the epithelial compartment, where it is the prevailing isoform.

5alpha-androstane-3beta,17beta-diol (3beta-Adiol) inhibits the migration of prostate cancer cell lines via ER-beta activation. (Dondi, Piccolella et al. 2010)

5alpha-androstane-3beta,17beta-diol activates ER-beta. (Handa, Pak et al. 2008) (Handa, Weiser et al. 2009)

5alpha-androstane-3beta,17beta-diol binds to ER-beta, but not to androgen receptors. (Oliveira, Coelho et al. 2007)

Androstanediol and Breast Cancer

Estrogen receptor-alpha promotes breast cell proliferation, while ER-beta inhibits proliferation and prevents breast cancer development via G2 cell cycle arrest. (Paruthiyil, Parmar et al. 2004)

5alpha-androstane-3beta,17beta-diol (3betaAdiol) induces breast cancer growth via ER-alpha. 3βAdiol is a weak agonist of ER-alpha growth induction. (Sikora, Cordero et al. 2009)

Atlas vertebra realignment

Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients (Bakris, Dickholtz et al. 2007)

Mitochondrial Dysfunction

Chronic fatigue syndrome and mitochondrial dysfunction (Myhill, Booth et al. 2009)

Mitochondrial diseases associated with cerebral folate deficiency (Garcia-Cazorla, Quadros et al. 2008)

Dr. Ron


Articles

Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients: a pilot study

            (Bakris, Dickholtz et al. 2007) Download

Anatomical abnormalities of the cervical spine at the level of the Atlas vertebra are associated with relative ischaemia of the brainstem circulation and increased blood pressure (BP). Manual correction of this mal-alignment has been associated with reduced arterial pressure. This pilot study tests the hypothesis that correcting mal-alignment of the Atlas vertebra reduces and maintains a lower BP. Using a double blind, placebo-controlled design at a single center, 50 drug naive (n=26) or washed out (n=24) patients with Stage 1 hypertension were randomized to receive a National Upper Cervical Chiropractic (NUCCA) procedure or a sham procedure. Patients received no antihypertensive meds during the 8-week study duration. The primary end point was changed in systolic and diastolic BP comparing baseline and week 8, with a 90% power to detect an 8/5 mm Hg difference at week 8 over the placebo group. The study cohort had a mean age 52.7+/-9.6 years, consisted of 70% males. At week 8, there were differences in systolic BP (-17+/-9 mm Hg, NUCCA versus -3+/-11 mm Hg, placebo; P<0.0001) and diastolic BP (-10+/-11 mm Hg, NUCCA versus -2+/-7 mm Hg; P=0.002). Lateral displacement of Atlas vertebra (1.0, baseline versus 0.04 degrees week 8, NUCCA versus 0.6, baseline versus 0.5 degrees , placebo; P=0.002). Heart rate was not reduced in the NUCCA group (-0.3 beats per minute, NUCCA, versus 0.5 beats per minute, placebo). No adverse effects were recorded. We conclude that restoration of Atlas alignment is associated with marked and sustained reductions in BP similar to the use of two-drug combination therapy.

Chronic fatigue syndrome and mitochondrial dysfunction

            (Myhill, Booth et al. 2009) Download

This study aims to improve the health of patients suffering from chronic fatigue syndrome (CFS) by interventions based on the biochemistry of the illness, specifically the function of mitochondria in producing ATP (adenosine triphosphate), the energy currency for all body functions, and recycling ADP (adenosine diphosphate) to replenish the ATP supply as needed. Patients attending a private medical practice specializing in CFS were diagnosed using the Centers for Disease Control criteria. In consultation with each patient, an integer on the Bell Ability Scale was assigned, and a blood sample was taken for the "ATP profile" test, designed for CFS and other fatigue conditions. Each test produced 5 numerical factors which describe the availability of ATP in neutrophils, the fraction complexed with magnesium, the efficiency of oxidative phosphorylation, and the transfer efficiencies of ADP into the mitochondria and ATP into the cytosol where the energy is used. With the consent of each of 71 patients and 53 normal, healthy controls the 5 factors have been collated and compared with the Bell Ability Scale. The individual numerical factors show that patients have different combinations of biochemical lesions. When the factors are combined, a remarkable correlation is observed between the degree of mitochondrial dysfunction and the severity of illness (P<0.001). Only 1 of the 71 patients overlaps the normal region. The "ATP profile" test is a powerful diagnostic tool and can differentiate patients who have fatigue and other symptoms as a result of energy wastage by stress and psychological factors from those who have insufficient energy due to cellular respiration dysfunction. The individual factors indicate which remedial actions, in the form of dietary supplements, drugs and detoxification, are most likely to be of benefit, and what further tests should be carried out.

Mitochondrial diseases associated with cerebral folate deficiency

(Garcia-Cazorla, Quadros et al. 2008) Download

Estrogen receptor beta and the progression of prostate cancer: role of 5alpha-androstane-3beta,17beta-diol

            (Dondi, Piccolella et al. 2010) Download

Prostate cancer (PC) develops in response to an abnormal activation of androgen receptor induced by circulating androgens and, in its initial stages, is pharmacologically controlled by androgen blockade. However, androgen ablation therapy often allows androgen-independent PC development, generally characterized by increased invasiveness. We previously reported that 5alpha-androstane-3beta,17beta-diol (3beta-Adiol) inhibits the migration of PC cell lines via the estrogen receptor beta (ERbeta) activation. Here, by combining in vitro assays and in vivo imaging approaches, we analyzed the effects of 3beta-Adiol on PC proliferation, migration, invasiveness, and metastasis in cultured cells and in xenografts using luciferase-labeled PC3 (PC3-Luc) cells. We found that 3beta-Adiol not only inhibits PC3-Luc cell migratory properties, but also induces a broader anti-tumor phenotype by decreasing the proliferation rate, increasing cell adhesion, and reducing invasive capabilities in vitro. All these 3beta-Adiol activities are mediated by ERbeta and cannot be reproduced by the physiological estrogen, 17beta-estradiol, suggesting the existence of different pathways activated by the two ERbeta ligands in PC3-Luc cells. In vivo, continuous administration of 3beta-Adiol reduces growth of established tumors and counteracts metastasis formation when PC3-Luc cells are engrafted s.c. in nude mice or are orthotopically injected into the prostate. Since 3beta-Adiol has no androgenic activity, and cannot be converted to androgenic compounds, the effects here described entail a novel potential application of this agent against human PC.

An alternate pathway for androgen regulation of brain function: activation of estrogen receptor beta by the metabolite of dihydrotestosterone, 5alpha-androstane-3beta,17beta-diol

            (Handa, Pak et al. 2008) Download

The complexity of gonadal steroid hormone actions is reflected in their broad and diverse effects on a host of integrated systems including reproductive physiology, sexual behavior, stress responses, immune function, cognition, and neural protection. Understanding the specific contributions of androgens and estrogens in neurons that mediate these important biological processes is central to the study of neuroendocrinology. Of particular interest in recent years has been the biological role of androgen metabolites. The goal of this review is to highlight recent data delineating the specific brain targets for the dihydrotestosterone metabolite, 5alpha-androstane, 3beta,17beta-diol (3beta-Diol). Studies using both in vitro and in vivo approaches provide compelling evidence that 3beta-Diol is an important modulator of the stress response mediated by the hypothalmo-pituitary-adrenal axis. Furthermore, the actions of 3beta-Diol are mediated by estrogen receptors, and not androgen receptors, often through a canonical estrogen response element in the promoter of a given target gene. These novel findings compel us to re-evaluate the interpretation of past studies and the design of future experiments aimed at elucidating the specific effects of androgen receptor signaling pathways.

A role for the androgen metabolite, 5alpha-androstane-3beta,17beta-diol, in modulating oestrogen receptor beta-mediated regulation of hormonal stress reactivity

            (Handa, Weiser et al. 2009) Download

Activation of the hypothalamic-pituitary-adrenal (HPA) axis is a basic response of animals to environmental perturbations that threaten homeostasis. These responses are regulated by neurones in the paraventricular nucleus of the hypothalamus (PVN) that synthesise and secrete corticotrophin-releasing hormone (CRH). Other PVN neuropeptides, such as arginine vasopressin and oxytocin, can also modulate activity of CRH neurones in the PVN and enhance CRH secretagogue activity of the anterior pituitary gland. In rodents, sex differences in HPA reactivity are well established; females exhibit a more robust activation of the HPA axis after stress than do males. These sex differences primarily result from opposing actions of sex steroids, testosterone and oestrogen, on HPA function. Ostreogen enhances stress activated adrenocorticotrophic hormone (ACTH) and corticosterone (CORT) secretion, whereas testosterone decreases the gain of the HPA axis and inhibits ACTH and CORT responses to stress. Data show that androgens can act directly on PVN neurones in the male rat through a novel pathway involving oestrogen receptor (ER)beta, whereas oestrogen acts predominantly through ERalpha. Thus, we examined the hypothesis that, in males, testosterone suppresses HPA function via an androgen metabolite that binds ERbeta. Clues to the neurobiological mechanisms underlying such a novel action can be gleaned from studies showing extensive colocalisation of ERbeta in oxytocin-containing cells of the PVN. Hence, in this review, we address the possibility that testosterone inhibits HPA reactivity by metabolising to 5alpha-androstane-3beta,17beta-diol, a compound that binds ERbeta and regulates oxytocin containing neurones of the PVN. These findings suggest a re-evaluation of studies examining pathways for androgen receptor signalling.

The androgen metabolite 5alpha-androstane-3beta,17beta-diol (3betaAdiol) induces breast cancer growth via estrogen receptor: implications for aromatase inhibitor resistance

            (Sikora, Cordero et al. 2009) Download

The aromatase inhibitors (AIs) are used to treat estrogen receptor-positive (ER+) breast tumors in post-menopausal women, and function by blocking the conversion of adrenal androgens to estrogens by the enzyme CYP19 aromatase. Breast cancer patients receiving AI therapy have circulating estrogen levels below the level of detection; however, androgen concentrations remain unchanged. We were interested in studying the effects of androgens on breast cancer cell proliferation under profound estrogen-deprived conditions. Using in vitro models of estrogen-dependent breast cancer cell growth we show that the androgens testosterone and 5alpha-dihydrotestosterone induce the growth of MCF-7, T47D and BT-474 cells in the absence of estrogen. Furthermore, we demonstrate that under profound estrogen-deprived conditions these breast cancer cells up-regulate steroidogenic enzymes that can metabolize androgens to estrogens. Lastly, we found that the downstream metabolite of 5alpha-dihydrotestosterone, 5alpha-androstane-3beta,17beta-diol (3betaAdiol), is estrogenic in breast cancer cells, and induces growth and ER-signaling via activation of ERalpha. In conclusion, our results show that breast cancer cells deprived of estrogen up-regulate steroidogenic enzymes and metabolize androgens to estrogen-like steroids. The generation of estrogen-like steroids represents a potential mechanism of resistance to aromatase inhibitors.


5alpha-Androstane-3beta,17beta-diol (3beta-diol), an estrogenic metabolite of 5alpha-dihydrotestosterone, is a potent modulator of estrogen receptor ERbeta expression in the ventral prostrate of adult rats

            (Oliveira, Coelho et al. 2007) Download

Prostate is one of the major targets for dihydrotestosterone (DHT), however this gland is also recognized as a nonclassical target for estrogen as it expresses both types of estrogen receptors (ER), especially ERbeta. Nevertheless, the concentrations of aromatase and estradiol in the prostate are low, indicating that estradiol may not be the only estrogenic molecule to play a role in the prostate. It is known that DHT can be metabolized to 5alpha-androstane-3beta,17beta-diol (3beta-diol), a hormone that binds to ERbeta but not to AR. The concentration of 3beta-diol in prostate is much higher than that of estradiol. Based on the high concentration of 3beta-diol and since this metabolite is a physiological ERbeta ligand, we hypothesized that 3beta-diol would be involved in the regulation of ERbeta expression. To test this hypothesis, adult male rats were submitted to castration followed by estradiol, DHT or 3beta-diol replacement. ERbeta and AR protein levels in the prostate were investigated by immunohistochemistry and Western blotting assays. The results showed that after castration, the structure of the prostate was dramatically changed and ERbeta and AR protein levels were decreased. Estradiol had just minor effects on the parameters analyzed. DHT-induced partial recovery of ERbeta while it was the most effective inductor of AR expression. Replacement with 3beta-diol-induced the highest levels of ERbeta, but was comparatively less effective in recovering the AR expression and the gland structure. These results offer evidence that one functional role of 3beta-diol in the prostate may be autoregulation of its natural receptor, ERbeta.


References

Bakris, G., M. Dickholtz, Sr., et al. (2007). "Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients: a pilot study." J Hum Hypertens 21(5): 347-52.

Dondi, D., M. Piccolella, et al. (2010). "Estrogen receptor beta and the progression of prostate cancer: role of 5alpha-androstane-3beta,17beta-diol." Endocr Relat Cancer 17(3): 731-42.

Garcia-Cazorla, A., E. V. Quadros, et al. (2008). "Mitochondrial diseases associated with cerebral folate deficiency." Neurology 70(16): 1360-2.

Handa, R. J., T. R. Pak, et al. (2008). "An alternate pathway for androgen regulation of brain function: activation of estrogen receptor beta by the metabolite of dihydrotestosterone, 5alpha-androstane-3beta,17beta-diol." Horm Behav 53(5): 741-52.

Handa, R. J., M. J. Weiser, et al. (2009). "A role for the androgen metabolite, 5alpha-androstane-3beta,17beta-diol, in modulating oestrogen receptor beta-mediated regulation of hormonal stress reactivity." J Neuroendocrinol 21(4): 351-8.

Myhill, S., N. E. Booth, et al. (2009). "Chronic fatigue syndrome and mitochondrial dysfunction." Int J Clin Exp Med 2(1): 1-16.

Oliveira, A. G., P. H. Coelho, et al. (2007). "5alpha-Androstane-3beta,17beta-diol (3beta-diol), an estrogenic metabolite of 5alpha-dihydrotestosterone, is a potent modulator of estrogen receptor ERbeta expression in the ventral prostrate of adult rats." Steroids 72(14): 914-22.

Paruthiyil, S., H. Parmar, et al. (2004). "Estrogen receptor beta inhibits human breast cancer cell proliferation and tumor formation by causing a G2 cell cycle arrest." Cancer Res 64(1): 423-8.

Sikora, M. J., K. E. Cordero, et al. (2009). "The androgen metabolite 5alpha-androstane-3beta,17beta-diol (3betaAdiol) induces breast cancer growth via estrogen receptor: implications for aromatase inhibitor resistance." Breast Cancer Res Treat 115(2): 289-96.