Danazol binding to steroid receptors in human uterine endometrium

Danazol alters mitochondria metabolism of fibrocystic breast Mcf10A cells

Fibrocystic Breast Disease (FBD) or Fibrocystic change (FC) affects about 60% of women at some time during their life. Although usually benign, it is often associated with pain and tenderness (mastalgia). The synthetic steroid danazol has been shown to be effective in reducing the pain associated with FBD, but the cellular and molecular mechanisms for its action have not been elucidated. We investigated the hypothesis that danazol acts by affecting energy metabolism. Effects of danazol on Mcf10A cells homeostasis, including mechanisms of oxidative phosphorylation, cytosolic calcium signaling and oxidative stress, were assessed by high-resolution respirometry and flow cytometry. In addition to fast physiological responses the associated genomic modulations were evaluated by Affimetrix microarray analysis. The alterations of mitochondria membrane potential and respiratory activity, downregulation of energy metabolism transcripts result in suppression of energy homeostasis and arrest of Mcf10A cells growth. The data obtained in this study impacts the recognition of direct control of mitochondria by cellular mechanisms associated with altered energy metabolism genes governing the breast tissue susceptibility and response to medication by danazol.

Effects of danazol on endothelial cell function and angiogenesis

OBJECTIVE

To determine the effects of the androgen-like synthetic steroid, danazol, on endothelial cell function and angiogenesis.

DESIGN

In vitro cell culture models were designed to investigate three critical steps involved in angiogenesis: endothelial cell proliferation, invasion, and tube formation.

SETTING

Research laboratory at a level one trauma center.

PATIENT(S)

Commercially available human umbilical vein endothelial cells (HUVEC) were purchased from a pooled patient source.

INTERVENTION(S)

The HUVEC cells were treated with danazol at concentrations ranging from 1 to 100 microM and evaluated using a series of angiogenesis assays.

MAIN OUTCOME MEASURE(S)

Absolute cells numbers were quantified using colorimetric methods and fluorescent dyes for cells exposed to danazol in both proliferation assays and invasion chambers. AngiQuant vl.33 software was used to evaluate the formation of capillary-like structures on extracellular matrix gels in the presence of danazol.

RESULT(S)

Endothelial cells scrutinized by our in vitro models exhibited decreased proliferation (up to 86%) and tube length (up to 115%) in the presence danazol. Cellular invasion through extracellular matrix, however, was not apparently affected by danazol under the conditions used.

CONCLUSION(S)

Danazol interfered with two of the three steps of angiogenesis studied in vitro. This data may help elucidate the mode of action for danazol in vivo.

Local application of danazol-loaded hyaluronic acid hydrogel to endometriosis in a rat model

OBJECTIVE

To evaluate the efficacy of a drug delivery system composed of danazol-loaded hyaluronic acid for local application to endometriosis.

DESIGN

Prospective, randomized study.

SETTING

Academic research unit of the department of obstetrics and gynecology in a university hospital.

PATIENT(S)

Adult female Sprague-Dawley rats.

INTERVENTION(S)

Danazol-loaded hyaluronic acid hydrogel (DZ-HA gel) was injected into the rat endometriosis model.

MAIN OUTCOME MEASURE(S)

Size and histological changes in experimental endometriosis, the concentration of danazol in the cyst wall and plasma, and estrous cycles were examined.

RESULT(S)

Histologically, DZ-HA gel-treated cysts displayed marked atrophy of the endometrial epithelium. Increased numbers of apoptotic cells and decreased numbers of proliferative cells were noted with 10 mg/mL DZ-HA gel. Size of treated cysts decreased to approximately 60% at 9 weeks after injection. The estrous cycles were not disturbed during DZ-HA gel treatment.

CONCLUSION(S)

Local injection of DZ-HA gel achieved endometrial atrophy of an experimental model of endometriosis without disturbing the sexual cycle. These results suggest that local application of DZ using this drug delivery system may prove useful for treating endometriosis.

Danazol mimics antigestagen action in first trimester termination of pregnancy

BACKGROUND

Based on steroid receptor binding and biologic activity, danazol was suspected to be an antigestagen.

OBJECTIVE

To compare with placebo test in first trimester termination of pregnancy (TOP) as a method for predilatation of the cervix prior to application of misoprostol.

METHODS

52 patients were randomised into two groups. Thereby, 26 women received 200 mg danazol vaginal suppositories three times during 2 days before administering 200 microg misoprostol and undergoing mechanical dilatation and vacuum aspiration 5h later. The other 26 received placebo suppositories and the same treatment otherwise.

RESULT

The uterine cervix was wider and less dilatation and time was needed for the surgical termination in the group pretreated with danazol. There were six cases of complete abortion within 5h of administering misoprostol in the danazol group; and none in the placebo group. After danazol treatment, 16 women exhibited signs of abortion versus four receiving the inert suppositories.

CONCLUSION

Pretreatment with 200mg danazol suppositories three times starting 36 h before administering misoprostol for cervical dilatation enhances the effect of prostaglandin on cervical dilatation and uterine contractions in a manner similar to antigestagens.

Suppression of anti-Candida activity of murine neutrophils by progesterone in vitro: a possible mechanism in pregnant women's vulnerability to vaginal candidiasis

Sex steroid hormones were examined for their effect on mycelial growth of Candida albicans, and the inhibitory activity of casein-induced murine peritoneal neutrophils against mycelial growth of C. albicans was examined in vitro using a crystal violet staining method or a [3H]glucose incorporation method. Four steroid hormones, danazol, estradiol, estriol and testosterone had no effect on mycelial growth of C. albicans, but progesterone appeared to convert the growth form of C. albicans from hyphal to yeast. Danazol (10(-6) M) and progesterone (10(-5) M) suppressed anti-Candida activity of neutrophils of non-treated mice, while testosterone, estradiol, and estriol did not. The anti-Candida activity of neutrophils of estradiol-pretreated mice was clearly suppressed by progesterone even at 10(-6) M which corresponded to its plasma concentration in pregnant women in the third trimester. The physiological significance of this suppressive effect of progesterone was discussed in relation to the vulnerability of pregnant women to vaginal candidiasis.

Biological implications of estrogen and androgen effects on androgen receptor and its mRNA levels in human uterine endometrium

It has been shown that some effects of testosterone are different from those of its 5 alpha-reduced metabolite, dihydrotestosterone. Briefly, activities of testosterone might be related to cellular differentiation, whereas dihydrotestosterone acts on cellular proliferation. The number of testosterone binding sites in the uterine endometrium was increased by estradiol dipropionate, and this increase was down-regulated by testosterone cypionate. Dihydrotestosterone-specific binding sites in the endometrium were not modulated by estradiol dipropionate and testosterone cypionate. The dissociation constants of the binding sites for testosterone and dihydrotestosterone were not altered by these steroids. Estradiol dipropionate with or without testosterone cypionate induced androgen receptor mRNA expression in the endometrium. In conclusion, testosterone might predominantly affect cellular differentiation in the endometrium.

Danazol decreases transcription of estrogen receptor gene in human monocytes

1. Administration of danazol for over one month reduced the levels of estrogen receptor (ER) and its mRNA to approximately 50 and 20%, respectively in monocytes. 2. Danazol did not alter the degradation rate of ER mRNA in monocytes. 3. Danazol decreased the transcription rate of ER gene to approximately 50% in monocytes in a run-on assay. 4. Danazol may release estrogen predominance via the reduction of transcription for ER gene, which leads to the reduction of ER mRNA and ER expressions in monocytes.

Effects of danazol and medroxyprogesterone acetate on estrogen-(estradiol and estriol) specific binding sites in rabbit uterus

In rabbit uterus, the presence of separate specific binding sites for not only estradiol but also estriol has been proposed. These sites may be correlated with an antiestradiol effect. Therefore, this study was designed to investigate the effect of antiestrogenic agents such as danazol and medroxyprogesterone acetate (MPA), especially on the estriol binding sites. Danazol and MPA in combination with estradiol were administered subcutaneously to immature female rabbits daily for 10 days, and resulted in a significant (p < 0.05) decrease in uterine weight and estradiol binding sites in the uterus. Treatment with MPA significantly (p < 0.05) decreased the level of estriol binding sites, but treatment with danazol resulted in this to a minimal extent in the uterus primed by estradiol. MPA did not bind to estradiol and estriol binding sites, while danazol at a high concentration bound to estriol binding sites with some affinity, but not to estradiol binding sites in the uterine cytosol of estrogen-primed rabbits. These results suggest that within the antiproliferative effect of danazol and MPA (an antiestrogenic action on estrogen-stimulated uterine growth) there are likely to be specific differences between some of the possible mechanisms of danazol and MPA in their action at the estriol binding site.

The hypothalamic-pituitary-ovarian axis in patients with endometriosis is suppressed by leuprolide acetate but not by danazol

OBJECTIVE

To investigate the effects of leuprolide acetate (LA), a GnRH agonist (GnRH-a), and of danazol on the hypothalamic-pituitary-ovarian axis in patients with endometriosis.

DESIGN

Ten patients were divided into LA and danazol treatment groups.

MEASURES

Serum levels of E2, immunoreactive and bioactive LH, pulsatility of LH, and gonadotropins release by GnRH. Changes in serum E2 levels by hMG administration during LA treatment.

RESULTS

Serum E2 level decreased to near castrated levels during the LA treatment, while it remained unchanged during the danazol treatment. Leuprolide acetate administration resulted in a significant suppression of the serum level of bioactive LH, of the pulsatility of LH release, of the pituitary response to GnRH injection, and of the elevation in the serum E2 level by hMG administration, but danazol treatment did not show these suppressive effects.

CONCLUSION

Our results suggest that the hormonal actions of LA and danazol on endometriosis are different from each other, especially in the suppression of serum E2 level.

Tissue factors influencing growth and maintenance of endometriosis

The unpredictable response of endometriosis to steroids and its recurrence after therapy, led us to hypothesize a possible further control of this pathology by factors other than steroids. The presence of estrogen, progesterone and epidermal growth factor receptors (ER, PR, EGFr) was evaluated using immunohistochemistry before and after therapy with Danazol or a gonadotropin-releasing hormone analogue (GnRHa), Buserelin. EGFr, ER and PR were present in 100% of endometrial specimens, and in 71%, 29% and 49% of endometriotic implants, respectively. Danazol and GnRHa reduced immunohistochemical staining for EGFr antisera in the endometrial and endometriotic specimens. About 21% of endometriosis were EGFr positive and ER negative, suggesting a potential role of epidermal growth factor in growth and maintenance of endometrial ectopia.

Different effects on oestrogen binding sites and anti-oestrogenic action of danazol and progesterone

Rabbit uterus contains type I and II oestrogen binding sites in the cytosol, and nuclear fractions. Oestrogen-stimulated increase in uterine weight was inhibited by concurrent treatment with progesterone or danazol. Oestrogen-induced type I binding sites were decreased by progesterone and to a lesser extent by danazol, while oestrogen-induced type II sites were decreased almost equally in the two groups. Neither progesterone nor danazol alone caused any detectable changes in uterine weight. These findings may suggest that the anti-oestrogenic effect on uterine weight is more correlated with the change in type II binding sites of oestrogen than that in type I sites. Thus, danazol may exert anti-oestrogenic actions through a pathway independent from that of progesterone.

Ovarian suppression induced with Buserelin or danazol in the management of endometriosis: a randomized, comparative study

The effectiveness of Buserelin (Hoechst-Roussel Pharmaceuticals, Inc., Somerville, NJ) (0.2 mg subcutaneously [SC] or 1.2 mg intranasally [IN] per day) and danazol (800 mg per day) in inducing ovarian suppression for the management of endometriosis was compared in a prospective randomized study. During 6 months of treatment, peripheral follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol concentrations were suppressed to a similar degree in both groups. Symptomatic improvement and laparoscopically assessed regression of endometriotic lesions also were comparable. After treatment, 8 of 18 infertile women treated with Buserelin and 5 of 8 treated with danazol conceived. General and hypoestrogenic side effects were similar in both groups, while androgenic and anabolic were more frequent with danazol. High density lipoprotein (HDL)-cholesterol increased in the Buserelin and decreased in the danazol group. The study indicates that at the dose tested, buserelin and danazol induce a similar degree of ovarian suppression resulting in a comparable clinical improvement and regression of endometriotic lesions.

Effects of danazol, gonadotropin-releasing hormone agonist, and estrogen/progestogen combination on experimental endometriosis in the ovariectomized rat

Direct effects of a gonadotropin-releasing hormone agonist (GnRHa), danazol, or estrogen/progestogen (E/P) on experimental endometriosis were evaluated in castrated female rats. Endometrial explants decreased in size following castration, but there was no further change in the treatment groups. Histologic examination indicated atrophy and regression of experimental endometriosis in all groups of castrated animals. As expected, following castration, serum estradiol (E2) became undetectable, serum progesterone (P4) decreased, and cytosolic E2 and P4 binding capacity in the endometrial explants was lower. However, in danazol-treated animals, serum P4 and E2 receptor concentrations were significantly higher than in all other castrated groups, and in both danazol and E/P treated animals, concentrations of P4 receptor were significantly higher than in castrated controls. In contrast, GnRHa treatment had no effect on serum E2 and P4 levels nor on E2 or P4 receptors. The authors conclude that danazol and E/P preparations may have a direct effect on the ectopic endometrium through interaction with steroid receptors.

Growth inhibition by danazol in a human endometrial cancer cell line with estrogen-independent progesterone receptors

Since we recently found that danazol, an isoxazol derivative of ethinyltestosterone, has a growth-inhibitory effect on human endometrial cancer cells in primary culture, the effects of danazol on a human endometrial cancer cell line (IK-90 cells), which contains estrogen-independent progesterone receptors (PR), were investigated in the present study. The addition of danazol (1 nM-1 microM) in culture medium caused a decrease in the growth of IK-90 cells in a dose-dependent manner. Competitive binding studies showed that danazol effectively binds to PR in IK-90 cells, and the binding affinity for PR was estimated to be 6.0% of that of R5020. The addition of 1 microM danazol in culture medium resulted in a rapid and significant increase in nuclear PR with a concomitant decrease in cytoplasmic PR in the cells. These findings suggest that danazol has a growth-inhibitory effect on human endometrial adenocarcinoma cells directly through PR system in the cells.

Steroid analogs inhibit hormone binding by an extract from Nippostrongylus brasiliensis (Nematoda)

1. An extract from the rodent nematode Nippostrongylus brasiliensis contained putative receptors that bound radiolabeled sex hormones, based on isoelectric focusing. 2. Binding of radiolabeled testosterone by receptors at pH 4.4 was highly inhibited by the androgen analogs, testosterone-3-oxime and 4-aza-5-androsten-3-on-17 beta-ol. 3. Binding of radiolabeled progesterone by receptors at pH 6.4 was highly inhibited by the progesterone analogs 3,5-seco-4-norpregnan-5-on-3-oic acid and 19-norethisterone or 21-deoxycorticosterone. 4. Binding of radiolabeled 17 beta-estradiol by receptors at pH 4.9 was highly inhibited by epiandrosterone. 5. In vivo development of N. brasiliensis to the adult was partially inhibited by selected steroid analogs.

Danazol binds to progesterone receptors and inhibits the growth of human endometrial cancer cells in vitro

Based on our recent findings that danazol, an isoxazol derivative of ethinyltestosterone, has a profound growth-inhibitory effect on an established human endometrial adenocarcinoma cell line, the effects of danazol on cancer cells from human endometrial adenocarcinomas obtained by hysterectomy were investigated in the present study. Of the 22 uterine adenocarcinomas, estrogen, progesterone, and androgen receptors were found in 12, 14, and 4 tumors, respectively. Competitive binding studies showed that danazol specifically binds to progesterone and androgen receptors but not to estrogen receptors. Of the five cancer cells from five patients succeeded in primary cell culture, a marked inhibition of cell growth was demonstrated by addition of danazol in two cancer cells having progesterone but not androgen receptors. However, danazol did not affect the growth of the remaining three cancer cells lacking progesterone receptors. These results strongly suggest that danazol has a significant growth-inhibitory effect on human endometrial adenocarcinoma cells, possibly through progesterone receptors in the cells.

Direct biphasic effects of danazol on gonadotropin-dependent differentiation of cultured rat granulosa cells

The direct effects of danazol on granulosa cell differentiation were studied in vitro over a broad concentration range with a primary culture of rat granulosa cells. Whereas treatment with low-dose (defined herein as less than 10(-6) M) danazol by itself was without significant effect on basal steroid secretion, combined treatment with low-dose danazol (10(-7) M) and a minimally effective dose of follicle-stimulating hormone (FSH, 20 ng/ml) resulted in a substantial augmentation of the FSH effect. Although independent of the FSH dose employed, the effect of danazol proved dose- and time-dependent, with an apparent median effective dose of 3.6 +/- 0.3 X 10(-8) M. In contrast, high-dose danazol (defined herein as greater than 10(-6) M) produced dose-dependent inhibition of FSH (250 ng/ml)-supported steroid secretion. Taken together, our findings indicate that the effects of danazol on granulosa cell differentiation may be biphasic in nature, displaying a stimulatory low-dose component, followed by inhibition at higher dose levels.