Effect of HepG2 cell 3D cultivation on the metabolism of the anabolic androgenic steroid metandienone.

The elucidation of the metabolic fate of prohibited substances is crucial for the abuse detection. The human hepatocyte cell line HepG2 can be used to study biotransformation. In order to improve this in vitro model system, we compared the HepG2 spheroid generation using three different techniques: a forced floating, a scaffold-free and a scaffold-based method. We characterized the spheroids with regard to the expression levels of the proliferation marker Mki67, the liver-specific marker albumin and biotransformation enzymes. Moreover, the metandienone metabolite pattern was comparatively analysed by high-performance liquid chromatography mass spectrometry. With all three techniques, HepG2 spheroids were generated showing a degree of differentiation. The forced floating method resulted in very large spheroids (1 mm in diameter) showing signs of necrosis in the centre and a very low metandienone conversion rate. The spheroids formed by the two other techniques were comparable in size with 0.5 mm in diameter on average. Among the three different 3D cultivation methods, the HepG2 spheroids formed on Matrigel® as extracellular matrix were the most promising regarding biotransformation studies on anabolic androgenic steroids. Prospectively, HepG2 spheroids are a promising in vitro model system to study multidrug setups, drug-drug interactions and the biotransformation of other substance classes.

Cell culture as a toolbox to generate phase I metabolites for antidoping screening.

The knowledge of the biotransformation of compounds prohibited by the World Anti Doping Agency is of high concern as doping analyses are mostly based on the detection of metabolites instead of the parent compounds abused by athletes. While the self-administration of doping-relevant compounds is from an ethical point of view a rather problematic method to investigate metabolism, the usage of cell culture systems allows for studies on biotransformation in vitro. Five cell culture models with different tissue origin (liver, ovary, skin, kidney, and testis) were comparatively incubated with testosterone and epitestosterone as well as with the synthetic testosterone derivatives 17α-methyltestosterone and 4-chlorotestosterone to investigate the impact of synthetic modifications on phase I metabolic pathways. Cell culture supernatants were analyzed by high-performance liquid chromatography-tandem mass spectrometry. All cell lines possessed the default steroid phase I biotransformation reactions. The highest conversion rate was observed in ovarian (BG-1) and liver cells (HepG2). For BG-1 and skin cells (HaCaT), the 5α-reductase products 5α-dihydrotestosterone (for both) and 5α-androstane-3α/ß,17ß-diol (for BG-1 solely) were found to be prevailing after testosterone incubation. In kidney (COS-1) and HepG2 cells, the 17ß-hydroxysteroid dehydrogenase activity was predominant as supported by the observation that the 17α-OH (epitestosterone) and the methyl group (17α-methyltestosterone) impeded the conversion rate in these cell lines. In conclusion, future work should extend the characterization of the BG-1 and HepG2 cells on phase II metabolic pathways to examine whether they are suitable models for the generation of metabolite reference collections comparable to those obtained by human excretion studies.

Comparison of the three SARMs RAD-140, GLPG0492 and GSK-2881078 in two different in vitro bioassays, and in an in silico androgen receptor binding assay.

Selective androgen receptor modulators comprise compounds that bind as ligands to the androgen receptor and possess tissue-selective activities. Ideally, they show agonistic properties in anabolic target tissues, while inducing antagonistic or only weak agonistic effects in reproductive organs. Due to their myoanabolic effects, selective androgen receptor modulators are included in the list of prohibited substances and methods of the World Anti-Doping Agency. In the current investigation, the androgenic potential of RAD-140, GSK-2881078 and GLPG0492 was comparably investigated in two different in vitro bioassays. In the yeast androgen screen, the androgenic effects were lower than in the reporter gene assay in prostate carcinoma cells (e.g. for GSK-2881078, the EC50 values were 4.44 × 10-6M in the yeast screen and 3.99 × 10-9M in the prostate cells respectively). For future investigations, it is of importance whether the yeast androgen screen, which has been proven to detect androgenic compounds in urine, can detect an abuse of the selective androgen receptor modulators. Molecular modeling of the binding to the androgen receptor ligand binding domain suggests slight differences in the binding modes of RAD-140, GSK-2881078 and GLPG0492. In conclusion, androgenic activity of the three non-steroidal compounds in the two different in vitro test systems confirmed the results of the in silico modeling of the androgen receptor binding.

Androgen- and estrogen-receptor mediated activities of 4-hydroxytestosterone, 4-hydroxyandrostenedione and their human metabolites in yeast based assays.

4-Hydroxyandrost-4-ene-3,17-dione, also named formestane, is an irreversible aromatase inhibitor and therapeutically used as anti-breast cancer medication in post-menopausal women. Currently, no therapeutical indication led to approval of its 17-hydroxylated analog 4-hydroxytestosterone, an anabolic steroid. However, it is currently investigated in a clinical trial for breast cancer. In context with sports doping, aromatase inhibitors are administered to reduce estrogenic side effects of misused anabolic substances or their metabolites. Therefore, both substances are prohibited in sports by the World Anti-Doping Agency (WADA). Analysis of urinary phase I and phase II metabolites showed similar results for both compounds. In the current investigation, 4-hydroxyandrost-4-ene-3,17-dione, 4-hydroxytestosterone and seven of their described urinary metabolites as well as 2α-hydroxyandrostenedione were tested in the yeast androgen screen and the yeast estrogen screen. Androgenic effects were observed for all tested substances, except for one, which showed anti-androgenic properties. With regard to the yeast estrogen screen, estrogenic effects were observed for only two metabolites at rather high concentrations, while six out of the ten substances tested showed anti-estrogenic properties. In terms of the strong androgenic effect observed for 4-hydroxytestosterone (10-8 M), 4-hydroxyandrost-4-ene-3,17-dione (10-8 M) and two more urinary metabolites, the yeast androgen assay may also be used to trace abuse in urine samples.

Oleocanthal Modulates Estradiol-Induced Gene Expression Involving Estrogen Receptor α.

Oleocanthal is a bioactive compound from olive oil. It has attracted considerable attention as it is anti-inflammatory, antiproliferative, and has been shown to possess neuroprotective properties in vitro and in vivo. Delineated from its polyphenolic structure, the aim of this study was to characterize oleocanthal towards estrogenic properties. This might contribute to partly explain the beneficial effects described for the Mediterranean diet. Estrogenic properties of oleocanthal were assessed by different methods: a) stimulation of reporter gene activity in MVLN or RNDA cells either expressing estrogen receptor α or ß, b) stimulation of luciferase reporter gene activity in U2OS osteosarcoma cells expressing estrogen receptor α or ß, and c) elucidation of the impact on estradiol-induced gene expression in U2OS cells transduced with both estrogen receptors. Depending on the cell line origin, oleocanthal inhibited luciferase activity (MVLN, U2OS-estrogen receptor ß) or weakly induced reporter gene activity at 10 µM in U2OS-estrogen receptor α cells. However, oleocanthal inhibited stimulation of luciferase activity by estradiol from both estrogen receptors. Oleocanthal, if given alone, did not stimulate gene expression in U2OS cells, but it significantly modulated the response of estradiol. Oleocanthal enhanced the effect of estradiol on the regulation of those genes, which are believed to be regulated through heterodimeric estrogen receptors. As the estrogenic response pattern of oleocanthal is rather unique, we compared the results obtained with oleacein. Oleocanthal binds to both estrogen receptors inducing estradiol-agonistic or antiagonistic effects depending on the cell line. Regarding regulation of gene expression in U2OS-estrogen receptor α/ß cells, oleocanthal and oleacein enhanced estradiol-mediated regulation of heterodimer-regulated genes.

Assessment of the effects of naringenin-type flavanones in uterus and vagina.

The potential utilization of plant secondary metabolites possessing estrogenic properties as alternatives to the classical hormone replacement therapy (HRT) for the relief of postmenopausal complaints asks for an evaluation regarding the safety in reproductive organs. In order to contribute to the estimation of the safety profile of the flavanones naringenin (Nar), 8­prenylnaringenin (8PN) and 6­(1,1­dimethylally) naringenin (6DMAN), we investigated uterus and vagina derived from a three­day uterotrophic assay in rats. Also, we investigated the metabolite profile resulting from the incubation of the three substances with liver microsomes. While no metabolites were detectable for naringenin, hydroxylation products were observed for 8PN and 6DMAN after incubation with human as well as rat liver microsomes. The parent compound naringenin did not evoke any estrogenic responses in the investigated parameters. A significant increase of the uterine wet weight, uterine epithelial thickness and proliferating vaginal cells was observed in response to 8PN, questioning the safety of 8PN if applied in the human situation. In contrast, no estrogenic effects on the reproductive organs were observed for 6DMAN in the conducted study, rendering it the compound with a more promising safety profile, therefore justifying further investigations into its efficacy to alleviate postmenopausal discomforts.

Impact of a functionalized olive oil extract on the uterus and the bone in a model of postmenopausal osteoporosis.

PURPOSE: The Mediterranean diet rich in fruits, vegetables and olive oil has been related to a lower osteoporosis incidence and accordingly to a reduced fracture risk. These observations might be mediated by the active constituents of extra virgin olive oil, and especially polyphenols. In the context of exploring the features of olive oil active constituents on postmenopausal osteoporosis, an extra virgin olive oil total polyphenolic fraction (TPF) was isolated and its effect on the bone loss attenuation was investigated. METHODS: Female Lewis rats were ovariectomized and fed a diet enriched with a total phenolic extract of extra virgin olive oil in a concentration of 800 mg/kg diet. RESULTS: Oleocanthal, one compound of the polyphenolic fraction, showed a higher relative estrogen receptor binding affinity to the ERα compared to the ERß. While the TPF only slightly induced the uterine wet weight (490.7 ± 53.7 vs. 432.7 ± 23, p = 0.058), TPF regulated estrogen response genes in the uterus (progesterone receptor, antigen identified by monoclonal antibody Ki67, complement C3). Comparing the quantified bone parameters, the oral TPF substitution did not attenuate the ovariectomy-induced bone loss. CONCLUSIONS: The administration of extra virgin olive oil polyphenols regulated uterine estrogen response marker genes in an E2-agonistic manner. The bone loss induced by estrogen ablation was not mitigated by treatment with the polyphenolic extract.

Comparison of estrogenic responses in bone and uterus depending on the parity status in Lewis rats.

The reproductive transition of women through peri- to postmenopause is characterized by changes in steroid hormone levels due to the cessation of the ovarian function. Beside several complaints associated with these hormonal changes, the deterioration of the trabecular bone micro-architecture and the loss of skeletal mass can cause osteoporosis. At this life stage, women often have a reproductive history of one to several pregnancies. The ovariectomized skeletally mature rat (>10 months old) is one of the most commonly used animal models for postmenopausal osteoporosis research. Despite the fact that mammals can undergo up to several reproductive cycles (primi-/pluriparous), nulliparous animals are often used and the question whether changes in the hormonal milieu subsequently affect the skeleton and influence the outcome of intervention studies is often neglected in study designs. Therefore, the aim of the present study was to compare the estrogen responsiveness of nulliparous and pluriparous rats. For this purpose, one year old virgin or retired breeder Lewis rats were either sham operated or ovariectomized, whereas half of the ovariectomized animals received subcutaneous 17ß-estradiol pellets eight weeks after surgery. After another four weeks, the effects on the uterus were determined by expression analysis of estrogen-dependently regulated steroid receptor genes and well-established marker genes. Moreover, trabecular bone parameters in the tibia were analyzed by micro-computed tomography (µCT). Parity-dependency in estrogen responsiveness was observed with respect to the achieved serum E2 levels in response to similar E2 treatment. This led to differences both on the uterus wet weight and on the expression level of uterine target genes. In addition, a reversal of the ovariectomy-induced changes of the bone architecture after 17ß-estradiol substitution was only observed among the nulliparous. In conclusion, the observations of this study support parity-dependent differences in the responses to estrogenic compounds in the uterus and the bone of rats. These results indicate that the parity-status has an impact on the outcome of studies aiming at the investigation of estrogenic effects of compounds potentially used in hormone replacement and thus, this should be taken into consideration for further studies and particularly for the discussion of data obtained with the preclinical ovariectomized rat animal model.

Estimation of an early meaningful time point of bone parameter changes in application to an osteoporotic rat model with in vivo microcomputed tomography measurements.

The commonly used preclinical animal model of postmenopausal osteoporosis is the mature ovariectomized rat, whereby cessation of ovarian oestrogen production consequently results in bone volume reduction. The study aim was to precisely define the time course of structural changes resulting from ovariectomy and thereby reduce the time animals have to be treated to judge the effects of osteoporosis treatment. For this purpose, we assessed architectural changes by microcomputed tomography (µCT) during 10 weeks following ovariectomy or sham surgery at two-week intervals. Moreover, the trabecular microarchitecture of the lumbar vertebrae was assessed after necropsy. Besides this, serum biomarkers of bone turnover were determined. These data were in a new approach additionally correlated to femur mRNA expression profiles. We selected the osteoblast marker genes osteocalcin and type I collagen as well as the two osteoclast marker genes cathepsin k and tartrate-resistant acid phosphatase 5. The gene expression analysis suggested an activation of osteoblasts as well as octeoclasts. The significantly induced serum levels of osteocalcin and collagen degradation fragments also revealed this higher rate of bone turnover. Our results indicate that as soon as four weeks after ovariectomy the bone volume fraction exhibited a decline of 30% and 50% of the connectivity density. In addition, significant decreases of trabecular number and thickness as well as of the bone volume fraction were only observed in vertebrae of ovariectomized animals. Interestingly, changes of trabecular morphology were also found in the sham animals as a consequence of senescence.

Long-term effects of the rhapontic rhubarb extract ERr 731® on estrogen-regulated targets in the uterus and on the bone in ovariectomized rats.

The efficacy of ERr 731(®), a commercially available extract isolated from Rheum rhaponticum, in terms of menopausal complaints like hot flushes, depression, anxiety and vaginal dryness has been proven in a two-year clinical study. Further a recent preclinical study excluded unwanted side effects on the endometrium by showing a lack of stimulation of proliferation marker genes by ERr 731(®) or its constituents in the 3-day uterotrophic assay. The present study aimed at further substantiating the safety of ERr 731(®) in terms of endometrial hyperplasia and at the same time test for potential estrogenic effects in the bone. Therefore, ovariectomized (ovx) rats were treated in a dietary long-term administration for 90 days. Hence, the modulation of proliferation in the uterus was investigated by examining the effects on the mRNA expression of proliferation marker genes (Mki67, Pcna), on the estrogen-responsive gene C3 and on the estrogen receptors ERα and ERß. We additionally performed densitometry analysis of the proximal tibia metaphysis using peripheral computed tomography (pQCT) and quantified bone homeostasis markers in the serum to examine potential effects on the bone. In this study design, neither an uterotrophic response nor a modulation of proliferation marker genes on mRNA level has been observed as response to the long-term application of the rhapontic extract. Furthermore, no impact of the two administered ERr 731(®) doses on the E2 deprivation-induced bone loss has been evident at the end of the study. In conclusion, the observations from previous trials regarding the endometrial safety of ERr 731(®) have been supported by our experimental findings that exclude a stimulatory activity on proliferation in the uterus in a long-term administration in the young adult rat but no effect on the bone mineral density could be observed.