Anti-aromatase Activity Research Articles

Synthesis, Aromatase Inhibition, Cytotoxicity and Molecular Docking Studies of New Fluorinated and Non-fluorinated Thiourea Derivatives of Desloratadine.

Aromatase inhibitors are among the most effective treatment of the breast cancer. Aromatase catalyzes estrogen biosynthesis, which is a long-term cause of breast cancer. Current study describes the synthesis, purification of 26 new fluorinated and non-fluorinated thiourea derivatives of desloratadine (5), and their aromatase inhibition activity, cytotoxicity against cancer cell line (MDA-MB-231). Compounds 7v and 7l exhibited a significant anti-aromatase activity, while compounds 7a, 7g-h, 7m and 7u were also significant active against MDA-MB-231 cell line. Furthermore, the molecular docking studies revealed that active compounds form key interactions with the crucial amino acid of aromatase active site including TRP224, LEU477, CYS437, ALA438, MET374, ARG115, ILE305, and PHE221, which are responsible for the binding interaction of aromatase. All analogues were new, except 7b and 7k and also lacked cytotoxicity BJ human fibroblasts, with the exception of 5 and 7x. This selectivity makes this series particularly interesting for further studies.

The anti-aromatase and anti-estrogenic activity of plant products in the treatment of estrogen receptor-positive breast cancer

Despite being the focal point of decades of research, female breast cancer (BC) continues to be one of the most lethal cancers in the world. Given that 80 % of all diagnosed BC cases are estrogen receptor-positive (ER+) with carcinogenesis driven by estrogen-ERα signalling, current standard of care (SOC) hormone therapies are geared towards modulating the function and expression levels of estrogen and its receptors, ERα and ERβ. Currently, aromatase inhibitors (AIs), selective ER modulators (SERMs) and selective ER degraders (SERDs) are clinically prescribed for the management and treatment of ER+ BC, with the anti-aromatase activity of AIs abrogating estrogen biosynthesis, while the anti-estrogenic SERMs and SERDs antagonise and degrade the ER, respectively. The use of SOC hormone therapies is, however, significantly hampered by the onset of severe side-effects and the development of resistance. Given that numerous studies have reported on the beneficial effects of plant compounds and/or extracts and the multiple pathways through which they target ER+ breast carcinogenesis, recent research has focused on the use of dietary chemopreventive agents for BC management. When combined with SOC treatments, several of these plant components and/or extracts have demonstrated improved efficacy and/or synergistic impact. Moreover, despite a lack of in vivo investigations, plant products are generally reported to have a lower side-effect profile than SOC therapies and are therefore thought to be a safer therapeutic choice. Thus, the current review summarizes the findings from the last five years regarding the anti-aromatase and anti-estrogenic activity of plant products, as well as their synergistic anti-ER+ BC effects in combination with SOC therapies.

Bioactive compounds from four Indian medicinal plants have different potency to induce sex reversal in Nile tilapia: A chromatographic, molecular docking and in silico analysis.

Herbal plants such as Basella alba (Family: Basellaceae), Tribulus terrestris (Family: Zygophyllaceae), Asparagus racemosus (Family: Asparagaceae) and Mucuna pruriens (Family: Fabaceae) are mentioned in Indian traditional system of medicine Ayurveda to possess androgenic activity and increase male virility. The plants have been reported to improve testosterone level and sperm production in experimental male rodents as well. Male Nile tilapias grow more quickly than females and hence are preferred for monosex Nile tilapia culture. Ethanol extracts of B. alba leaves (EB) and T. terrestris seeds (ET), and methanol extract of A. racemosus roots (MA) and M. pruriens seeds (MM) were found effective to induce masculinization in Nile tilapia. The present study intends to evaluate the anti-aromatase activity of EB, ET, MA and MM, to identify the androgenic bioactive compounds in the extracts, and to determine their pharmacokinetics. The study may validate the use of those plant extracts and their major bioactive phytoconstituents in the field of aquaculture and pharmaceuticals. The four crude plant extracts were first fractioned through column and thin layer chromatography (TLC). Three days old Nile tilapia juveniles (mean weight 0.025±0.009g; mean length 12.50±0.12mm; n=50 fish/replicate, 3 replicates/treatment) were then fed diets fortified with the obtained fractions for 30 days. After 30 days, fish were sacrificed and gonad aromatase mRNA expression, and 11-ketotestosterone (11-KT) and estradiol (E2) levels were measured. Fractions yielding the highest male percentage for each plant were subject to gas chromatography-mass spectrometry (GC-MS) analysis. The in silico docking and SwissADME study were conducted with the components showing higher peak percentage in chromatogram. After column chromatography and TLC analysis, EB, ET, MM and MA yielded 6 (EB1 - EB6), 8 (ET1- ET8), 14 (MM1-MM14) and 5 (MA1- MA5) fractions, respectively. Fish fed EB2, ET2, MA2 and MM13 fraction fortified diets showed significantly (p<0.05) higher male percentage (92.32%-98.39%) compared to other treatment groups. EB2, ET2, MA2 and MM13 fed fish showed significantly (p<0.05) higher 11-KT level compared to control male (+247.52 - +397.76%) and lower E2 level compared to control female (-95.92% to -90.65%). Aromatase mRNA expression was significantly (p<0.05) down-regulated by all these four fractions (-1.32 to -5.65 fold) with respect to control female. GC-MS analysis revealed the presence of 1-Octadecene (OD) in EB2, Phenol, 2,4-bis(1,1-dimethylethyl) (PD) in ET2 and MA2, 9,12-Octadecadienoic acid (Z,Z)- (ODDA) in MM13. In silico molecular docking indicated that PD is more effective than ODDA and OD to inhibit aromatase. In addition, PD showed better pharmacokinetics and more drug-likeness compared to OD and ODDA in SwissADME analysis. The present results indicate that ET and MA are more potent to produce all-male tilapia by means of aromatase inhibition. PD can be an ideal compound to achieve masculinization in Nile tilapia through dietary administration, but further investigation is required.

Erkek İnfertilitesine Alternatif Farmakolojik Yaklaşım: Anti-Aromataz Bileşikler: Sistematik Derleme

Infertility is a reproductive system disease in which pregnancy does not occur despite long-term, regular and unprotected sexual intercourse. In the near future, it is estimated that approximately 15% of the world population will be affected by infertility and the majority of this will be male-induced infertility. In male infertility, 90% defective sperm production is effective and it is known that in infertile men, as a result of the increase in estrogen levels due to aromatase activity, the testosterone/estradiol ratio may decrease and spermatogenesis is impaired. Therefore, research on increasing intratesticular testosterone levels and improving impaired spermatogenesis has focused on aromatase inhibitors. However, since the efficacy and safety of aromatase inhibitors have not been clarified, it has been thought that anti-aromatase compounds with fewer side effects and stronger efficacy can be used as alternative therapeutic agents in the treatment of infertility. Phytoestrogens are estrogenic plant-derived compounds. Many have been shown to have aromatase inhibition, thereby increasing testosterone levels. In addition, it is known that there are different mechanisms that affect spermatogenesis apart from binding to estrogen receptors in their effects on the male reproductive system. Therefore, our aim is to review the latest developments and treatment approaches to natural polyphenolic compounds with anti-aromatase activity in male infertility. According to the literature, the most commonly used anti-aromatase compounds include resveratrol, quercetin, apigenin, and naringenin. All the compounds in this review were found to have positive effects on male infertility.

Biocatalytic transformation of steroidal drugs oxandrolone and ganaxolone, and aromatase inhibitory activity of transformed products

Glomerella fusarioides-mediated structural modifications of steroidal anabolic drug, oxandrolone (1), yielded a new product 17β,11α-dihydroxy-17α-methylandrosta-2-oxa-4-ene-3-one (2). Similarly, Cunninghamella elegans-catalyzed transformation of a steroidal anti-epileptic drug ganaxolone (3) afforded a new metabolite 14α-hydroxy-5α-pregnan-1-ene-3,20-dione (4). Structures of new metabolites 2 and 4 were deduced via 1D-, and 2D-NMR, HREI-, HRFAB-MS, and IR spectroscopic techniques. New derivative 2 showed a remarkable anti-aromatase activity with an IC50 = 0.6 ± 0.005 μM, when compared to substrate 1 (IC50 = 0.808 ± 0.07 μM), and standard anti-cancer drug exemestane (IC50 = 0.232 ± 0.031 μM). Ganaxolone (3) (IC50 = 13.76 ± 2.00 μM) also showed a good activity against human aromatase enzyme, while its derivative 4 was found to be inactive. Inhibition of aromatase enzyme is a key approach in the treatment of estrogen positive breast cancers. Compounds 1-4 were non-cytotoxic to 3T3 cell line (mouse fibroblast).

Anti-estrogenic and anti-aromatase activities of citrus peels major compounds in breast cancer

Estrogen signaling is crucial for breast cancer initiation and progression. Endocrine-based therapies comprising estrogen receptor (ER) modulators and aromatase inhibitors remain the mainstay of treatment. This study aimed at investigating the antitumor potential of the most potent compounds in citrus peels on breast cancer by exploring their anti-estrogenic and anti-aromatase activities. The ethanolic extract of different varieties of citrus peels along with eight isolated flavonoids were screened against estrogen-dependent breast cancer cell lines besides normal cells for evaluating their safety profile. Naringenin, naringin and quercetin demonstrated the lowest IC50s and were therefore selected for further assays. In silico molecular modeling against ER and aromatase was performed for the three compounds. In vivo estrogenic and anti-estrogenic assays confirmed an anti-estrogenic activity for the isolates. Moreover, naringenin, naringin and quercetin demonstrated in vitro inhibitory potential against aromatase enzyme along with anticancer potential in vivo, as evidenced by decreased tumor volumes. Reduction in aromatase levels in solid tumors was also observed in treated groups. Overall, this study suggests an antitumor potential for naringenin, naringin and quercetin isolated from citrus peels in breast cancer via possible modulation of estrogen signaling and aromatase inhibition suggesting their use in pre- and post-menopausal breast cancer patients, respectively.

Unveiling the mechanism of action behind the anti-cancer properties of cannabinoids in ER+ breast cancer cells: Impact on aromatase and steroid receptors

Breast cancer is the leading cause of cancer-related death in women worldwide. In the last years, cannabinoids have gained attention in the clinical setting and clinical trials with cannabinoid-based preparations are underway. However, contradictory anti-tumour properties have also been reported. Thus, the elucidation of the molecular mechanisms behind their anti-tumour efficacy is crucial to better understand its therapeutic potential. Considering this, our work aims to clarify the molecular mechanisms underlying the anti-cancer properties of the endocannabinoid anandamide (AEA) and of the phytocannabinoids, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), in estrogen receptor-positive (ER+) breast cancer cells that overexpress aromatase (MCF-7aro). Their in vitro effects on cell proliferation, cell death and activity/expression of aromatase, ERα, ERβ and AR were investigated. Our results demonstrated that cannabinoids disrupted MCF-7aro cell cycle progression. Unlike AEA and THC that induced apoptosis, CBD triggered autophagy to promote apoptotic cell death. Interestingly, all cannabinoids reduced aromatase and ERα expression levels in cells. On the other hand, AEA and CBD not only exhibited high anti-aromatase activity but also induced up-regulation of ERβ. Therefore, all cannabinoids, albeit by different actions, target aromatase and ERs, impairing, in that way, the growth of ER+ breast cancer cells, which is dependent on estrogen signalling. As aromatase and ERs are key targets for ER+ breast cancer treatment, cannabinoids can be considered as potential and attractive therapeutic compounds for this type of cancer, being CBD the most promising one. Thus, from an in vitro perspective, this work may contribute to the growing mass of evidence of cannabinoids and cannabinoids-based medicines as potential anti-cancer drugs.

QSAR studies on indole-azole Analogues using DTC tools; imidazole ring is more favorable for aromatase inhibition

Quantitative structure activity relationship (QSAR) studies have been performed on indole-azole based compounds to correlate molecular descriptors and aromatase inhibitory activity using Drug Theoretics and Cheminformatics (DTC) tools. For 2- and 3- [(aryl) (azolyl)methyl]indole derivatives (set-I), MATS4s, AATS4e, and ATSC7i showed good correlation with significant R2 and Q2 values as 0.93 and 0.83, while for 1-aryl-2-[(1H-imidazol-1-yl)methyl]-6-substituted-1H-indole derivatives (set-II), the derived QSAR model showed significant R2 and Q2 values as 0.93 and 0.82 respectively, with the descriptors AVP-0, MATS7s, minHaaCH. Electronic parameters such as high electronegativity and ionization potential have unfavourable influence on anti-aromatase activity of both series of compounds. Among the imidazole and 1, 2, 4-triazole rings, imidazole nucleus is more favourable due to its low electrostatic potential. The findings of the study might guide in future designing and development of more potent indole-azole based aromatase inhibitors.

Identification of chemical constituents responsible for potential androgenic efficacy of Withania somnifera and Chlorophytum borivilianum root solvent extracts for production of monosex Nile tilapia, Oreochromis niloticus

ABSTRACT Bioactivity-guided fractionation was performed between March and June 2019 to identify the phytoconstituents in extracts of Withania somnifera and Chlorophytum borivilianum that were responsible for androgenic efficacy by inducing maleness in Nile tilapia. Fish hatchlings were fed diets containing water, methanol, and ethanol extracts at 0.5, 0.75, and 0.9 gm/kg feed concentrations. For W. somnifera, the highest male percentage (89.63 ± 0.9) was obtained with methanol extract at 0.75 gm/kg feed concentration. For C. borivilianum, the highest male percentage (93.64 ± 0.9) was obtained with ethanol extract at 0.75 gm/kg feed concentration. Three fractions of methanol extract of Withania somnifera roots (W1 to W3) and six fractions of ethanol extract of Chlorophytum borivilianum roots (S1 to S6) were obtained through column chromatography followed by TLC. During dietary treatment (0.75 gm/kg feed) with those fractions, W1 and S4 showed higher male percentage than others. Gas chromatography-mass spectrometry analysis of W1 and S4 revealed the presence of various unsaturated fatty acids with antiaromatase activity that might be responsible for the androgenic effect of the extracts.

Discovery of a multi-target compound for estrogen receptor-positive (ER+) breast cancer: Involvement of aromatase and ERs

Despite intense research, breast cancer remains the leading cause of cancer-related death in women worldwide, being estrogen receptor-positive (ER+) the most common subtype. Nowadays, aromatase inhibitors (AIs), the selective estrogen receptor modulator (SERM) tamoxifen and the selective estrogen receptor down-regulator (SERD) fulvestrant are used as therapeutic options for ER+ breast cancer, since they interfere directly with the production of estrogens and with the activation of estrogen-dependent signaling pathways. Despite the success of these treatments, the occurrence of resistance limits their clinical efficacy, demanding the development of novel therapies. Recently, multi-target compounds emerged as promising therapeutic strategies for ER+ breast cancer, as they can potentially modulate several important targets simultaneously. In line with this, in this work, the anti-cancer properties and multi-target action of 1,1-Bis(4-hydroxyphenyl)-2-phenylbut-1-ene, tamoxifen bisphenol (1,1-BHPE), were evaluated in an ER+ breast cancer cell model (MCF-7aro cells). Molecular docking analysis predicted that 1,1-BHPE was able to bind to aromatase, ERα and ERβ. In vitro studies showed that, although it did not present anti-aromatase activity, 1,1-BHPE reduced aromatase protein levels and interfered with ERα and ERβ signaling pathways, acting as an ERα antagonist and inducing ERβ up-regulation. Through these mechanisms, 1,1-BHPE was able to impair breast cancer growth and induce apoptosis. This represents an important therapeutic advantage because the main players responsible for estrogen production and signaling are modulated by a single compound. To the best of our knowledge, this is the first study describing the anti-cancer properties of 1,1-BHPE as a multi-target compound specific for ER+ breast cancer.

Tributyltin enhanced anxiety of adult male zebrafish through elevating cortisol level and disruption in serotonin, dopamine and gamma-aminobutyric acid neurotransmitter pathways

Tributyltin (TBT), a widely and persistently distributed organontin, has been well documented to disrupt reproduction and behaviors in animals due to its anti-aromatase activity. TBT has been also reported to enhance anxiety in several fish species, whereas the mechanism underlying remains largely unknown. To investigate the disruption of TBT on fish anxiety and the mechanisms possibly involved, adult male zebrafish (Danio rerio) were treated with TBT (100 and 500 ng/L) for 28 days and anxiety behavior was further investigated using a novel tank dive test. Result showed that TBT treatment significantly enhanced the total time of the fish spent in the lower half, delayed the onset time to the higher half of the tank and increased the total duration of freezing of the fish, indicating an enhanced anxiety in TBT-treated fish. Accordingly, TBT sharply elevated the cortisol levels in plasma in a concentration-dependent manner, suggesting that the elevated cortisol level might be involved in the enhanced anxiety. Although the expression of crha was significantly increased and crhbp was significantly decreased in the brain of TBT-treated fish which is consistent to the elevated cortisol level, the expressions of actha and acthb were sharply down-regulated. In contrast, the expressions of genes responsible for the synthesis and action of serotonin (5-HT) (pet1, thp2 and htr1aa), dopamine (DA) (th1, slc6a3, drd2a and drd2b) and gamma-aminobutyric acid (GABA) (gad2 and gabrg2) were all significantly inhibited. The down-regulation of these pivotal genes acting in 5-HT, DA and GABA neurotransmitter systems in response to TBT corresponded well with the TBT-enhanced anxiety in fish. It was thus strongly suggested that these neurotransmitters might be also involved in TBT-enhanced anxiety in adult male zebrafish. The present study extended our understanding of the neurotoxicity of TBT on the anxiety control and behavioral modulation in fish.

Cannabidiol (CBD) but not tetrahydrocannabinol (THC) dysregulate in vitro decidualization of human endometrial stromal cells by disruption of estrogen signaling

Decidualization, which comprises proliferation and differentiation of endometrial stromal cells (ESCs), is essential for the establishment of a receptive endometrium and pregnancy to occur. A deregulation of decidualization has been associated with miscarriage, infertility and other pregnancy-related disorders. The role of estradiol (E2) on decidualization has already been shown, since it regulates proliferation of ESCs and expression of progesterone receptor. In this study, we investigated the effects of phytocannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD), in proliferation and differentiation of ESCs, as well as, in E2 metabolism/signaling. We found that CBD, but not THC, inhibits ESCs differentiation. We also show that CBD prevents the increase on transcript levels of CYP19A1 gene and the elevation of E2 levels that are observed in differentiating ESCs. Moreover, we found that CBD presents anti-aromatase activity. In overall, we highlight a novel effect of CBD on human endometrial differentiation, which may lead to infertility problems.

Effects of new C6-substituted steroidal aromatase inhibitors in hormone-sensitive breast cancer cells: Cell death mechanisms and modulation of estrogen and androgen receptors

Estrogen receptor-positive (ER+) breast cancers require estrogens for their growth. Aromatase inhibitors (AIs) are considered the first-line therapy for this type of tumours. Despite the well-established clinical benefit of this therapy, the search for novel potent AIs that present higher efficacy and fewer side effects is still demanded. Thus, taking into account the known interactions of the natural substrate, androstenedione, within the aromatase active-site, a range of new steroidal compounds have been designed, synthesized and studied by our group. In this work, it was evaluated in MCF-7aro, an ER+ breast cancer cell line that overexpress aromatase, the anti-aromatase efficacy and the biological effects of eight new AIs: 6α-methyl-5α-androst-3-en-17-one (1a), 6α-methyl-3α,4α-epoxy-5α-androstan-17-one (3a), 6α-methylandrost-4-ene-3,17-dione (9), 6α-allylandrosta-1,4-diene-3,17-dione (13), 6α-allylandrost-4-ene-3,17-dione (15), 6α-allylandrost-4-en-17-one (17), 6β-hydroxyandrost-4-ene-3,17-dione (19) and 6α-hydroxyandrost-4-ene-3,17-dione (20). Their anti-cancer properties were elucidated, as well as, the dependence of their mechanism of action on aromatase inhibition and/or on steroid receptors modulation, such as estrogen and androgen receptors, which are key targets for this type of cancer. Results demonstrate that the studied AIs present high anti-aromatase activity, disrupt MCF-7aro cell cycle progression and induce apoptosis, through the mitochondrial pathway. Compounds 1a, 3a, 9, 13, 15 and 17 exhibited an aromatase-dependent effect on cells and, interestingly, steroids 9 and 13 displayed the ability to decrease aromatase protein levels without affecting CYP19A1 mRNA levels. Furthermore, the effects of compounds 1a, 3a and 15 were dependent on ER and on AR modulation, whereas compounds 9 and 19 were only dependent on AR modulation. From a clinical point of view, these actions can be considered as a therapeutic advantage for this type of tumours. Thus, new promising AIs that impair ER+ breast cancer cell growth, by acting on aromatase, and even, on ER and AR were discovered. Furthermore, new insights on the most favourable structural modifications in the steroidal core structure were provided, helping to a more rational drug design of new and potent AIs.

Anandamide targets aromatase: A breakthrough on human decidualization

In each menstrual cycle endometrial stromal cells (hESC) proliferate and differentiate into specialized decidual cells, a process termed decidualization, which regulates endometrial receptivity. Decidualization is mainly controlled by sex ovarian hormones, estradiol (E2) and progesterone. E2 plays an important role in the expression of the progesterone receptor and promotes the endometrial stromal cells differentiation. Our group previously reported that anandamide (AEA) impairs decidualization through cannabinoid receptor 1 (CB1). In this study, we hypothesized whether AEA inhibitory effect on cell decidualization could be mediated through interaction with aromatase and consequent interference in estradiol production/signaling. We used an immortalized human endometrial stromal cell line (St-T1b) and human decidual fibroblasts (HdF) derived from human term placenta. In cells exposed to a differentiation stimulus, AEA-treatment prevents the increase of the expression of CYP19A1 gene encoding aromatase, E2 levels and of estradiol receptor expression, that are observed in differentiating cells. Regarding CYP19A1 mRNA levels, the effect was partially reverted by a CB1 receptor antagonist and by a COX2 inhibitor. In addition, we report that AEA presents anti-aromatase activity in placental microsomes, the nature of the inhibition being the uncommon mixed type as revealed by the kinetic studies. Structural analysis of the AEA-Aromatase complexes determined that AEA may bind to the active site pocket of the enzyme. In overall we report that AEA inhibits aromatase activity and may affect E2 signaling crucial for the decidualization process, indicating that a deregulation of the endocannabinoid system may be implicated in endometrial dysfunction and in fertility/infertility disorders.

A novel GC-MS methodology to evaluate aromatase activity in human placental microsomes: a comparative study with the standard radiometric assay.

Estrogens are key factors in the development of the estrogen receptor-positive (ER+) breast cancer. Estrogens, estrone (E1), and estradiol (E2) production is achieved by aromatase, a cytochrome P450 enzyme that has androgens, androstenedione (AD), and testosterone (T) as substrates. Nowadays, third-generation aromatase inhibitors (AIs) are considered the gold-standard treatment for ER+ breast cancer in postmenopausal women as well as in premenopausal women with ovary ablation. Aromatase activity assessment still relies on radiometric assays that are expensive, hazardous, and non-environmentally friendly. Thus, in order to overcome these disadvantages, a new methodology was developed to evaluate aromatase activity, based on dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS). The enzymatic reaction was carried out in human placental microsomes, using AD as substrate, and the anti-aromatase activity was measured by determining the conversion percentage of AD into E1 (ratio E1/AD) using isotopic analogues as internal standards. The method showed good linearity (r2 = 0.9908 for AD and 0.9944 for E1), high accuracy (more than 74% for AD and more than 66% for E1), high extraction efficiency, and good intra-day and inter-day precision (below 14%, 4 levels). In this work, the IC50 valuesof the third-generation AIs, anastrozole, letrozole, and exemestane, obtained from theradiometric assay are also compared, and similar IC50 values are described. This method is a good alternative to the current radiometric assay, being fast and sensitive with a good extraction efficiency, accuracy, and recovery. In addition, it may be applied for the evaluation of the anti-aromatase activity of new potential AIs. Graphical abstract.

Synthesis of novel trans-4-(phthalimidomethyl)- and 4-(imidazol-1-ylmethyl)-3-indolyl-tetrahydroisoquinolinones as possible aromatase inhibitors

The reaction of homophthalic anhydride with 1H-indol-3-carbaldimines was used for the preparation of trans- and cis-2-alkyl-3-indolyl-1-oxotetrahydroisoquinolin-4-carboxylic acids 3a–d. The stereochemistry of the reaction was investigated by means of 1H NMR spectroscopy. The carboxylic group of trans-3a–d was transformed stereoselectively via 4-hydroxymethyltetrahydroisoquinolin-1-ones into 4-(phthalimidomethyl)-derivatives trans-6a,b and 4-(imidazolylmethyl)-derivatives trans-8b–d. Compounds trans-6a,b and 8b–d were tested for antiaromatase activity, and the preliminary results showed that the phthalimidomethylisoquinolinone trans-6b at 50 μM concentration decreased the aromatase enzyme activity with 40%.

Inhibition of Aromatase and Cell Proliferation of Breast Cancer and Human Placenta Choriocarcinoma by Prunus persica Extracts

Prunus persica has been used as a source of traditional medicine in many countries for the treatment of different diseases in females. In the present study, cytotoxicity and reactive oxygen species scavenging effects of Prunus persica extract on human breast cancer and placenta choriocarcinoma cell lines were evaluated. Besides this, regulations of oestrogen synthesis and antiaromatase activity were observed on human placenta choriocarcinoma cells. Ethyl acetate and butanol fractions had the maximum cytotoxic activity among all the fractions. In comparison to butanol fraction, ethyl acetate fraction was found to scavenge maximum intracellular reactive oxygen species, which was correlated with its total phenolic and flavonoid contents. Ethyl acetate was found to reduce the aromatase activity by 50 % at the concentration of 200 µg/ml. This inhibitory effect on aromatase was accompanied by reduced 17β-estradiol levels in JEG-3 cells. It seemed that the ethyl acetate and n-butanol fractions of Prunus persica or its active compound appears to be acting through dual mechanisms, i.e. improvement of antioxidant system and by suppressing aromatase; it may potentially be used as therapeutic agent for the treatment of breast cancer. These findings suggested that Prunus persica extract could be an aromatase inhibitor for the treatment of oestrogen-sensitive breast cancer.

Synthesis, molecular docking, and QSAR study of sulfonamide-based indoles as aromatase inhibitors

Thirty four of indoles bearing sulfonamides (11–44) were synthesized and evaluated for their anti-aromatase activities. Interestingly, all indole derivatives inhibited the aromatase with IC50 range of 0.7–15.3 μM. Indoles (27–36) exerted higher aromatase inhibitory activity than that of ketoconazole. The phenoxy analogs 28 and 34 with methoxy group were shown to be the most potent compounds with sub-micromolar IC50 values (i.e., 0.7 and 0.8 μM, respectively) without affecting to the normal cell line. Molecular docking demonstrated that the indoles 28, 30 and 34 could occupy the same binding site on the aromatase pocket and share several binding residues with those of the natural substrate (androstenedione), which suggested the competitive binding could be the mode of inhibition of the compounds. The most potent analog 28 could mimic H-bond interactions of the natural androstenedione with MET374 and ASP309 residues on the aromatase. QSAR model also revealed that the para-phenoxy indole (28) affords the higher value of electronegativity descriptor MATS6e as well as the higher inhibitory activity compared with that of the ortho-phenoxy compound (34). The study highlighted a series of promising indoles to be potentially developed as novel aromatase inhibitors for therapeutics.

Exemestane potency is unchanged by common nonsynonymous polymorphisms in CYP19A1: results of a novel anti-aromatase activity assay examining exemestane and its derivatives.

Exemestane (EXE) treats estrogen receptor positive (ER+) breast cancer in postmenopausal women by inhibiting the estrogen‐synthesizing cytochrome P450 CYP19A1. Variability in the severity and incidence of side effects as well as overall drug efficacy may be partially explained by genetic factors, including nonsynonymous variation in CYP19A1, also known as aromatase. The present study identified phase I EXE metabolites in human liver microsomes (HLM) and investigated mechanisms that may alter the extent of systemic estrogen deprivation in EXE‐treated women with breast cancer, including whether functional polymorphisms in aromatase cause differential inhibition by EXE and whether EXE metabolites possess anti‐aromatase activity. The potency of EXE and ten of its derivatives was measured with HEK293‐overexpressed wild type aromatase (CYP19A1*1) using a rapid novel UPLC tandem mass spectrometry method. Of the ten compounds assayed, five were poor inhibitors (IC 50 ˃ 50 μmol/L) of wild type aromatase while five others, including the major metabolite, 17β‐dihydroexemestane (17β‐DHE), exhibited moderate potency, with IC 50 values ranging between 1.2 and 7.1 μmol/L. The anti‐aromatase activity of EXE was also tested with two common allozymes, aromataseThr201Met (CYP19A1*3) and aromataseArg264Cys (CYP19A1*4). Differential inhibition of variant aromatase is unlikely to account for variable clinical outcomes as EXE‐mediated inhibition of aromataseThr201Met (IC 50 = 0.86 ± 0.12 μmol/L) and aromataseArg264Cys (IC 50 = 1.7 ± 0.65 μmol/L) did not significantly differ from wild type (IC 50 = 0.92 ± 0.17 μmol/L). Although less potent than the parent drug, these results suggest that active metabolites may contribute to the therapeutic mechanism of EXE.

Anti-tumor efficacy of new 7α-substituted androstanes as aromatase inhibitors in hormone-sensitive and resistant breast cancer cells

The majority of breast cancer cases are estrogen receptor positive (ER+). Although, third-generation aromatase inhibitors (AIs) are used as first-line treatment in post-menopausal women, they cause endocrine resistance and bone loss, which limits their success. Therefore, there is a demand to discover new potent molecules, with less toxicity that can circumvent these drawbacks. Our group has previously demonstrated that new 7α-substituted steroidal molecules, 7α-(2ξ,3ξ-epoxypropyl)androsta-1,4-diene-3,17-dione (3), 7α-allylandrost-4-ene-3,17-dione (6), 7α-allylandrost-4-en-17-one (9), 7α-allyl-3-oxoandrosta-1,4-dien-17β-ol (10) and 7α-allylandrosta-1,4-diene-3,17-dione (12) are potent AIs in placental microsomes. In this work, it was investigated their anti-aromatase activity and in vitro effects in sensitive and resistant breast cancer cells. All the steroids efficiently inhibit aromatase in breast cancer cells, allowing to establish new structure-activity relationships for this class of compounds. Moreover, the new AIs can inhibit breast cancer cell growth, by causing cell cycle arrest and apoptosis. The effects of AIs 3 and 12 on sensitive cells were dependent on aromatase inhibition and androgen receptor (AR), while for AI 9 and AI 10 were AR- and ER-dependent, respectively. In addition, it was shown that all the AIs can sensitize resistant cancer cells being their behavior similar to the sensitive cells. In summary, this study contributes to the understanding of the structural modifications in steroidal scaffold that are translated into better aromatase inhibition and anti-tumor properties, providing important information for the rational design/synthesis of more effective AIs. In addition, allowed the discovery of new potent 7α-substituted androstane molecules to inhibit tumor growth and prevent endocrine resistance.