The neuro-steroid, 3beta androstene 17alpha diol exhibits potent cytotoxic effects on human malignant glioma and lymphoma cells through different programmed cell death pathways

Dehydroepiandrosterone and Its Metabolite 5-Androstenediol: New Therapeutic Targets and Possibilities for Clinical Application

Dehydroepiandrosterone and its sulfate are the most abundant steroids in humans. The metabolism of dehydroepiandrosterone can differ significantly depending on the organ or tissue and the subtype of steroid receptors expressed in it. For dehydroepiandrosterone, as a precursor of all steroid hormones, intracrine hormonal activity is inherent. This unique feature could be beneficial for the medicinal application, especially for the local treatment of various pathologies. At present, the clinical use of dehydroepiandrosterone is limited by its Intrarosa® (Quebec city, QC, Canada) prasterone) 6.5 mg vaginal suppositories for the treatment of vaginal atrophy and dyspareunia, while the dehydroepiandrosterone synthetic derivatives Triplex, BNN 27, and Fluasterone have the investigational status for the treatment of various diseases. Here, we discuss the molecular targets of dehydroepiandrosterone, which open future prospects to expand its indications for use. Dehydroepiandrosterone, as an oral drug, is surmised to have promise in the treatment of osteoporosis, cachexia, and sarcopenia, as does 10% unguent for skin and muscle regeneration. Also, 5-androstenediol, a metabolite of dehydroepiandrosterone, is a promising candidate for the treatment of acute radiation syndrome and as an immunostimulating agent during radiopharmaceutical therapy. The design and synthesis of new 5-androstenediol derivatives with increased bioavailability may lead to the appearance of highly effective cytoprotectors on the pharmaceutical market. The argumentations for new clinical applications of these steroids and novel insights into their mechanisms of action are discussed.

Isoforms of autophagy-related proteins: role in glioma progression and therapy resistance

Autophagy is the process of recycling and utilization of degraded organelles and macromolecules in the cell compartments formed during the fusion of autophagosomes with lysosomes. During autophagy induction the healthy and tumor cells adapt themselves to harsh conditions such as cellular stress or insufficient supply of nutrients in the cell environment to maintain their homeostasis. Autophagy is currently seen as a form of programmed cell death along with apoptosis and necroptosis. In recent years multiple studies have considered the autophagy as a potential mechanism of anticancer therapy in malignant glioma. Although, subsequent steps in autophagy development are known and well-described, on molecular level the mechanism of autophagosome initiation and maturation using autophagy-related proteins is under investigation. This article reviews current state about the mechanism of autophagy, its molecular pathways and the most recent studies on roles of autophagy-related proteins and their isoforms in glioma progression and its treatment.

New 6,19-oxidoandrostan derivatives obtained by biotransformation in environmental filamentous fungi cultures

Background

Steroid compounds with a 6,19-oxirane bridge possess interesting biological activities including anticonvulsant and analgesic properties, bacteriostatic activity against Gram-positive bacteria and selective anti-glucocorticoid action, while lacking mineralocorticoid and progestagen activity.

Results

The study aimed to obtain new derivatives of 3β-acetyloxy-5α-chloro-6,19-oxidoandrostan-17-one by microbial transformation. Twelve filamentous fungal strains were used as catalysts, including entomopathogenic strains with specific activity in the transformation of steroid compounds. All selected strains were characterised by high biotransformation capacity for steroid compounds. However, high substrate conversions were obtained in the cultures of 8 strains: Beauveria bassiana KCh BBT, Beauveria caledonica KCh J3.4, Penicillium commune KCh W7, Penicillium chrysogenum KCh S4, Mucor hiemalis KCh W2, Fusarium acuminatum KCh S1, Trichoderma atroviride KCh TRW and Isaria farinosa KCh KW1.1. Based on gas chromatography (GC) and nuclear magnetic resonance (NMR) analyses, it was found that almost all strains hydrolysed the ester bond of the acetyl group. The strain M. hiemalis KCh W2 reduced the carbonyl group additionally. From the P. commune KCh W7 and P. chrysogenum KCh S4 strain cultures a product of D-ring Baeyer–Villiger oxidation was isolated, whereas from the culture of B. bassiana KCh BBT a product of hydroxylation at the 11α position and oxidation of the D ring was obtained. Three 11α-hydroxy derivatives were obtained in the culture of I. farinosa KCh KW1.1: 3β,11α-dihydroxy-5α-chloro-6,19-oxidoandrostan-17-one, 3β,11α,19-trihydroxy-5α-chloro-6,19-oxidoandrostan-17-one and 3β,11α-dihydroxy-5α-chloro-6,19-oxidoandrostan-17,19-dione. They are a result of consecutive reactions of hydrolysis of the acetyl group at C-3, 11α- hydroxylation, then hydroxylation at C-19 and its further oxidation to lactone.

Conclusions

As a result of the biotransformations, seven steroid derivatives, not previously described in the literature, were obtained: 3β-hydroxy-5α-chloro-6,19-oxidoandrostan-17-one, 3β,17α-dihydroxy-5α-chloro-6,19-oxidoandrostane, 3β-hydroxy-5α-chloro-17α-oxa-D-homo-6,19-oxidoandrostan-17-one, 3β,11α-dihydroxy-5α-chloro-17α-oxa-D-homo-6,19-oxidoandrostan-17-one and the three above–mentioned 11α-hydroxy derivatives. This study will allow a better understanding and characterisation of the catalytic abilities of individual microorganisms, which is crucial for more accurate planning of experiments and achieving more predictable results.

Autophagy and Autophagic Cell Death: Uncovering New Mechanisms Whereby Dehydroepiandrosterone Promotes Beneficial Effects on Human Health

Dehydroepiandrosterone (DHEA) is the most abundant steroid hormone in human serum and a precursor of sexual hormones. Its levels, which are maximum between the age of 20 and 30, dramatically decline with aging thus raising the question that many pathological conditions typical of the elderly might be associated with the decrement of circulating DHEA. Moreover, since its very early discovery, DHEA and its metabolites have been shown to be active in many pathophysiological contexts, including cardiovascular disease, brain disorders, and cancer. Indeed, treatment with DHEA has beneficial effects for the cure of these and many other pathologies in vitro, in vivo, and in patient studies. However, the molecular mechanisms underlying DHEA effects have been only partially elucidated. Autophagy is a self-digestive process, by which cell homeostasis is maintained, damaged organelles removed, and cell survival assured upon stress stimuli. However, high rate of autophagy is detrimental and leads to a form of programmed cell death known as autophagic cell death (ACD). In this chapter, we describe the process of autophagy and the morphological and biochemical features of ACD. Moreover, we analyze the beneficial effects of DHEA in several pathologies and the molecular mechanisms with particular emphasis on its regulation of cell death processes. Finally, we review data indicating DHEA and structurally related steroid hormones as modulators of both autophagy and ACD, a research field that opens new avenues in the therapeutic use of these compounds.

Differential Effect of Wortmannolone Derivatives on MDA-MB-231 Breast Cancer Cells

BACKGROUND/AIM

The survival rate of women diagnosed with triple-negative breast-cancer (TNBC) remains low. Hence, this study aimed at the chemical and biological optimization of furanosteroid derivatives for the treatment of this type of malignancy using TNBC cells.

MATERIALS AND METHODS

Semi-synthetic analogs of wortmannolone (1-6) that negatively affected the aberrant pathways in tumor cells were evaluated in hormone-independent breast cancer cells using western blot and cell-cycle analysis.

RESULTS

Wortmannolone derivatization generated NF-ĸB inhibitors as new lead structures for further development. Compound (3) was found to be the most significantly active lead.

CONCLUSION

Structure-activity analysis in the present study showed that acetylation of the hydroxyl groups and substitution on C3 and C17 of wortmannolone enhanced biological activity. Alpha-substitution of the acetyl group in C3 on ring A (compound 3) resulted in ROS inducing effect; however, presence of an acetyl group in β-position of C3 displayed the highest NF-ĸB p65 inhibitory activity (0.60 μM).

Structural Stereochemistry of Androstene Hormones Determines Interactions with Human Androgen, Estrogen, and Glucocorticoid Receptors

DHEA, 17α-AED, 17β-AED, and 17β-AET exhibit strong biological activity that has been attributed to androgenic, estrogenic, or antiglucocorticoid activity in vivo and in vitro. This study compared DHEA, 17α-AED, 17β-AED, and 17β-AET for their ability to activate the human AR, ER, and GR and determine the relative androgenicity, estrogenicity, and glucocorticoid activity. The results show that, at the receptor level, these androstene hormones are weak AR and even weaker ER activators. Direct androstene hormone activation of the human AR, ERα, and ERβ may not be essential for their biological function. Similarly, these hormones indirectly activated the human GR, only in the presence of high dexamethasone concentrations. These results underscore the major difference between androstene hormone interactions with these nuclear receptors and their biological effects.

Structure-activity relationship (SAR) analysis of a family of steroids acutely controlling steroidogenesis

Steroids metabolically derive from lipid cholesterol, and vertebrate steroids additionally derive from the steroid pregnenolone. Pregnenolone is derived from cholesterol by hydrolytic cleavage of the aliphatic tail by mitochondrial cytochrome P450 enzyme CYP11A1, located in the inner mitochondrial membrane. Delivery of cholesterol to CYP11A1 comprises the principal control step of steroidogenesis, and requires a series of proteins spanning the mitochondrial double membranes. A critical member of this cholesterol translocation machinery is the integral outer mitochondrial membrane translocator protein (18kDa, TSPO), a high-affinity drug- and cholesterol-binding protein. The cholesterol-binding site of TSPO consists of a phylogenetically conserved cholesterol recognition/interaction amino acid consensus (CRAC). Previous studies from our group identified 5-androsten-3β,17,19-triol (19-Atriol) as drug ligand for the TSPO CRAC motif inhibiting cholesterol binding to CRAC domain and steroidogenesis. To further understand 19-Atriol's mechanism of action as well as the molecular recognition by the TSPO CRAC motif, we undertook structure-activity relationship (SAR) analysis of the 19-Atriol molecule with a variety of substituted steroids oxygenated at positions around the steroid backbone. We found that in addition to steroids hydroxylated at carbon C19, hydroxylations at C4, C7, and C11 contributed to inhibition of cAMP-mediated steroidogenesis in a minimal steroidogenic cell model. However, only substituted steroids with C19 hydroxylations exhibited specificity to TSPO, its CRAC motif, and mitochondrial cholesterol transport, as the C4, C7, and C11 hydroxylated steroids inhibited the metabolic transformation of cholesterol by CYP11A1. We thus provide new insights into structure-activity relationships of steroids inhibiting mitochondrial cholesterol transport and steroidogenic cholesterol metabolic enzymes.

17α-androstenediol-mediated oncophagy of tumor cells by different mechanisms is determined by the target tumor

Δ5-androstene-3β,17α-diol (17α-AED) mediates oncophagy of human myeloid, glioma, and breast tumor cells by apoptotic- and autophagic-programmed cell death pathways, whereas the 17β-epimer does not. In hematologically derived myeloid tumor cells, 17α-AED induced apoptosis, as determined by TUNEL staining, caspase, PARP activation, and electron microscopy. In contrast, 17α-AED treatment of glioma cells of neuroectodermal lineaged induced autophagy, evident by the presence of acidic vesicular organelles, LC3 processing, and upregulation of beclin-1. Proliferation inhibition studies on primary and established glioma cells demonstrated that the IC-50 of the steroid is ∼15 μM. In the case of breast cancer cells, the bioactivity of 17α-AED is independent of the expression of estrogen or androgen receptors. Collectively, oncophagy is induced by 17α-AED treatment in human tumor cells and proceeds by the induction of either autophagy or apoptosis. The neoplastic cell determines which oncophagic pathway is utilized.

Oxidative metabolism of dehydroepiandrosterone (DHEA) and biologically active oxygenated metabolites of DHEA and epiandrosterone (EpiA)--recent reports

Dehydroepiandrosterone (DHEA) is a multifunctional steroid with a broad range of biological effects in humans and animals. DHEA can be converted to multiple oxygenated metabolites in the brain and peripheral tissues. The mechanisms by which DHEA exerts its effects are not well understood. However, evidence that the effects of DHEA are mediated by its oxygenated metabolites has accumulated. This paper will review the panel of oxygenated DHEA metabolites (7, 16 and 17-hydroxylated derivatives) including a number of 5α-androstane derivatives, such as epiandrosterone (EpiA) metabolites. The most important aspects of the oxidative metabolism of DHEA in the liver, intestine and brain are described. Then, this article reviews the reported biological effects of oxygenated DHEA metabolites from recent findings with a specific focus on cancer, inflammatory and immune processes, osteoporosis, thermogenesis, adipogenesis, the cardiovascular system, the brain and the estrogen and androgen receptors.

The neuro-steroid, 5-androstene 3β,17α diol; induces endoplasmic reticulum stress and autophagy through PERK/eIF2α signaling in malignant glioma cells and transformed fibroblasts

In this study, we identified a mechanism by which the neuro-steroid, 5-androstene 3β,17α diol (17α-AED) induces autophagy in human malignant glioma cells and transformed fibroblasts. 17α-AED treatment induced endoplasmic reticulum (ER) stress, identified by the partial activation of an unfolded protein response in T98G, U87MG, U251MG, LN-18, LN-229 and LN-Z308 glioma cell lines. In this regard, there were increased levels of CCAAT/enhancer-binding protein homologous protein (CHOP) and glucose-regulated protein of 78kDa transcripts but no splicing of X-box-binding protein 1 mRNA or processing of activating transcription factor-6 in glioma cells treated with the neuro-steroid. 17α-AED induced eukaryotic translational initiation factor 2α (eIF2α) phosphorylation in glioma cells which correlated with microtubule-associated protein-light chain 3 (LC3) conversion from LC3-I to -II. In transformed murine embryonic fibroblasts (MEFs) that are deficient of eIF2α function or T98G glioma cells transfected with a dominant-negative eIF2α construct, 17α-AED induced LC3 conversion was significantly reduced as compared to control cells. Neuro-steroid treatment caused the activation of the eIF2α kinase, protein kinase-like ER kinase (PERK) but not other eIF2α kinases in glioma cells. Moreover, eIF2α phosphorylation and LC3 conversion, in response to 17α-AED treatment, was blocked in MEFs that lacked PERK activity. T98G cells transfected with a dominant-negative PERK construct exhibited an attenuated response to neuro-steroid treatment in terms of decreases in: eIF2α activation; CHOP expression; the incidence of autophagy; and cytotoxicity. These results demonstrate that ER stress is linked to 17α-AED induced autophagy by PERK/eIF2α signaling in human malignant glioma cells and transformed fibroblasts.

Autophagy and the functional roles of Atg5 and beclin-1 in the anti-tumor effects of 3beta androstene 17alpha diol neuro-steroid on malignant glioma cells

In this study, we demonstrate that the anti-tumor activity of the neuro-steroid, 3beta androstene 17alpha diol (17alpha-AED) on malignant glioma cells is mediated by the induction of autophagy. 17alpha-AED can inhibit the proliferation an induce cell death of multiple, unrelated gliomas with an IC(50) between 8 and 25muM. 17alpha-AED treatment induced the formation of autophagosomes and acidic vesicular organelles in human malignant gliomas which was blocked by bafilomycin A1 or 3-methyladenine. Cleavage of microtubule-associated protein-light chain 3 (LC3), an essential step in autophagosome formation, was detected in human malignant glioma cells exposed to 17alpha-AED. In 17alpha-AED treated T98G glioma cells there was an increase in the autophagy related proteins Atg5 and beclin-1. Silencing of ATG5 or beclin-1 with small interfering RNA significantly reduced the incidence of autophagy in 17alpha-AED treated malignant gliomas and attenuated the cytotoxic effects of the neuro-steroid indicating that the induction of autophagy mediates the anti-glioma activity of 17alpha-AED rather than serving as a cyto-protective response. These results demonstrate that 17alpha-AED possesses significant anti-glioma activity when used at pharmacologically relevant concentrations in vitro and the cytotoxic effects are resultant from the induction of autophagy.