Synthesis and evaluation of the antiproliferative activity of benzylidenes of 16-dehydroprogesterone series

Design and synthesis of phosphoryl-substituted steroidal pyridazines (Pho-STPYRs) as potent estrogen receptor alpha inhibitors: targeted treatment of hormone-dependent breast cancer cells

Estrogen receptor alpha (ERα) is an important target for the discovery of new therapeutic drugs against hormone-dependent breast cancer. A series of phosphoryl-substituted steroidal pyridazines (Pho-STPYRs) were synthesized and biologically evaluated as potent ERα inhibitors. Pho-STPYRs showed cytotoxicity against breast cancer cells with IC50 values of 5.9 μM and higher. Pho-STPYRs 33 and 34 [IC50 (MCF7) = 6.5 and 5.9 μM, respectively] were found to block the expression of ERα, the main driver of breast cancer growth, and modulate the ERK, cyclin D1, and CDK4 pathways. Compound 34 showed selectivity, anti-estrogenic potency and high antiproliferative efficacy in combination with the AKT inhibitor. Molecular docking was used to more accurately define the binding mode of lead compounds 33 and 34 to ERα. The selectivity analysis showed that lead compounds 33 and 34 produce no effects on cytochromes P450, including CYP7A1, CYP7B1, CYP17A1, CYP19A1, and CYP21A2. In a word, Pho-STPYRs 33 and 34 are promising ERα inhibitors for the treatment of hormone-dependent breast cancer.

Synthesis and Biological Evaluation of Chalconesulfonamides: En Route to Proapoptotic Agents with Antiestrogenic Potency

Breast and other estrogen receptor α-positive cancers tend to develop resistance to existing drugs. Chalcone derivatives possess anticancer activity based on their ability to form covalent bonds with targets acting as Michael acceptors. This study aimed to evaluate the anticancer properties of a series of chalcones (7a-l) with a sulfonamide group attached to the vinyl ketone moiety. Chalconesulfonamides showed a potent antiproliferative effect at low micromolar concentrations against several cancer cell lines, including ERα-positive 4-hydroxytamoxifen-resistant MCF7/HT2. Immunoblotting of samples treated with the lead compound 7e revealed its potent antiestrogenic activity (ERα/GREB1 axis) and induction of PARP cleavage (an apoptosis marker) in breast cancer cells. The obtained compounds represent a promising basis for further development of targeted drugs blocking hormone pathways in cancer cells.

Discovery and biological evaluation of pregnenolone selenocyanoamides with potential anticancer and antimicrobial activities

Starting with pregnenolone, a 20-carbonyl group was converted into an amino group through a series of chemical reactions. This amino group was further converted into selenocyanoalkylamide, leading to the synthesis of six pregnenolone selenocyanoalkylamide derivatives. These compounds were then screened for antitumor activity in vitro, yielding promising results. Compounds 4b-4f show higher inhibitory activity than the positive control abiraterone and 2-methoxyestradiol, with IC50 values lower than 10 μmol/L against breast, ovarian, and cervical cancer cell lines that closely related to human hormone expression levels. The Annexin V assay of compound 4f revealed that compounds inhibited tumor cell proliferation primarily through the induction of programmed apoptosis. The zebrafish test results indicated that compound 4d had significant inhibitory activity against MCF-7 cell xenografts in vivo. Moreover, the antibacterial test indicated that compounds 4a and 4d-4e had better inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) than the positive controls vancomycin and ampicillin. These results suggest that these compounds may hold promise as novel antitumor agents or antimicrobial agents for further study.

Discovery of highly potent proapoptotic antiestrogens in a series of androst-5,16-dienes D-modified with imidazole-annulated pendants

Heterocyclic derivatives of steroid hormones are potent anticancer agents, which are used in the chemotherapy of breast and prostate cancers. Here, we describe a novel series of androstenes, D-modified with imidazole-annulated pendants, with significant anticancer activity. Novel C17-linked imidazole-annulated heterocyclic derivatives of dehydropregnenolone acetate were synthesized by the cyclocondensation with amidines using 3β-acetoxy-21-bromopregna-5,16-dien-20-one as the substrate. The antiproliferative potency of all the synthesized compounds was evaluated against human prostate (22Rv1) and human breast (MCF7) cancer cell lines and cytochromes P450. The lead compound, imidazo[1,2-a]pyridine derivative 3h, was revealed to be a promising candidate for future anticancer drug design, particularly against ERα-positive breast cancer. Lead compound 3h was found to be selective against MCF7 cells with IC₅₀ of 0.1μM and to act as both a potent selective agent blocking estrogen receptor α, which is involved in the stimulation of breast cancer growth, and an effective apoptosis inducer. The potential ability of compound 3h to bind to ERα was studded using molecular docking and molecular dynamics simulation. The selectivity analysis showed that lead steroid 3h produces no effects on cytochromes P450 CYP17A1, CYP7A1, and CYP21A2.

Novel pentacyclic derivatives and benzylidenes of the progesterone series cause anti-estrogenic and antiproliferative effects and induce apoptosis in breast cancer cells

The promising antitumor effects of progesterone derivatives have been identified in many studies. However, the specific mechanism of action of this class of compounds has not been fully described. Therefore, in this study, we investigated the antiproliferative and (anti)estrogenic activities of novel pentacyclic derivatives and benzylidenes of the progesterone series. The antiproliferative effects of the compounds were evaluated on hormone-dependent MCF7 breast cancer cells using the MTT test. Estrogen receptor α (ERα) activity was assessed by a luciferase-based reporter assay. Immunoblotting was used to evaluate the expression of signaling proteins. All benzylidenes demonstrated inhibitory effects with IC₅₀ values below 10 µM, whereas pentacyclic derivatives were less active. These patterns may be associated with the lability of the geometry of benzylidene molecules, which contributes to an increase in the affinity of interaction with the receptor. The selected compounds showed significant anti-estrogenic potency. Benzylidene 1d ((8 S,9 S,10R,13 S,14 S,17 S)-17-[(2E)-3-(4-fluorophenyl)prop-2-enoyl]-10,13-dimethyl-1,2,6,7,8,9,11,12,14,15-decahydrocyclopenta[a]phenanthren-3-one) was the most active in antiproliferative and anti-estrogenic assays. Apoptosis induced by compound 1d was accompanied by decreases in CDK4, ERα, and Cyclin D1 expression. Compounds 1d and 3d were characterized by high inhibitory potency against resistant breast cancer cells. Apoptosis induced by the leader compounds was confirmed by PARP cleavage and flow cytometry analysis. Compound 3d caused cell arrest in the G2/M phase. Further analysis of novel derivatives of the progesterone series is of great importance for medicinal chemistry, drug design, and oncology.

Human estrogen receptor α antagonists, part 2: Synthesis driven by rational design, in vitro antiproliferative, and in vivo anticancer evaluation of innovative coumarin-related antiestrogens as breast cancer suppressants

New twelve in silico designed coumarin-based ERα antagonists, namely 3DQ-1a to 3DQ-1е, were synthesized and confirmed as selective ERα antagonists, showing potencies ranging from single-digit nanomolar to picomolar. The hits were confirmed as selective estrogen receptor modulators and validated as antiproliferative agents using MCF-7 breast cancer cell lines exerting from picomolar to low nanomolar potency, at the same time showing no agonistic activity within endometrial cell lines. Their mechanism of action was inspected and revealed to be through the inhibition of the Raf-1/MAPK/ERK signal transduction pathway, preventing hormone-mediated gene expression on either genomic direct or genomic indirect level, and stopping the MCF-7 cells proliferation at G₀/G₁ phase. In vivo experiments, by means of the per os administration to female Wistar rats with pre-induced breast cancer, distinguished six derivatives, 3DQ-4a, 3DQ-2a, 3DQ-1a, 3DQ-1b, 3DQ-2b, and 3DQ-3b, showing remarkable potency as tumor suppressors endowed with optimal pharmacokinetic profiles and no significant histopathological profiles. The presented data indicate the new compounds as potential candidates to be submitted in clinical trials for breast cancer therapy.

Synthesis and crystal structures of D-annulated pentacyclic steroids: looking within and beyond AR signalling in prostate cancer

Carbocyclic steroids D-annulated at 16α and 17α positions with a 5-membered ring E are easily accessible via the interrupted Nazarov cyclization. Three steroid series have been structurally studied: chlorine-containing D-annulated...

Secosteroidal hydrazides: Promising scaffolds for anti-breast cancer agents

A convenient and selective approach to 13,17-secoestra-1,3,5(10)-trien-17-oic acid hydrazides and their N'-(het)arylmethylene derivatives was disclosed and these novel types of secosteroids were screened for cytotoxicity against hormone-dependent human breast cancer cell line MCF-7. A number of 13,17-secoestra-1,3,5(10)-trien-17-oic acid [N'-(het)arylmethylene]hydrazides show significant cytotoxic effect comparable or superior to that for reference drug cisplatin. Compound 3l exhibits the highest activity with the IC₅₀ value of about 2 μM and is 2.8 times more active than cisplatin. Hit 13,17-secoestra-1,3,5(10)-trien-17-oic acid [N'-(het)arylmethylene]hydrazides 3d, 3l and 3q are characterized by high cytotoxicity and good selectivity towards MCF-7 breast cancer cells. The synthesized secosteroids may be considered as new promising antitumor agents.

Light-driven photoswitching of quinazoline analogues of combretastatin A-4 as an effective approach for targeting skin cancer cells

A novel quinazoline series of photoswitchable combretastatin A-4 (CA-4) analogues were synthesized and their photochemical properties and antiproliferative activity against A431 epidermoid carcinoma cells were studied. It was found that quinazoline analogues, in contrast to the majority of the known CA-4, exhibit high antiproliferative activity in the E-form as well. Photoswitching of the E-form to the Z-form resulted in a multiple (9-fold) increase in antiproliferative activity. 1H NMR monitoring showed that these compounds are very resistant to UV (λ = 365 nm) or sunlight irradiation and do not undergo photodegradation with a loss of antiproliferative activity that is inherent in heterocyclic analogues of CA-4. Similar photoswitching and an increase in antiproliferative activity are observed on exposure to sunlight. A selected compound (1a-Z51) in sub-micromolar concentrations induced apoptosis in A431 cells, while rad50/ATM/p53 were not involved in cell death. The growth of A431 cells was significantly inhibited after combination treatment with compound 1a-Z51 and chemotherapy drugs (cisplatin or 5-fluorouracil). In summary, the quinazoline analogues of CA-4 represent a promising strategy to achieve a photoswitchable potency for the treatment of cancers, including the development of combination therapies.

Reactivity of steroidal 1-azadienes toward enamines: an approach to novel chiral penta- and hexacyclic steroids

The chemical behavior of steroidal N-sulfonyl-1-azadienes toward carbonyl compounds, in the presence of pyrrolidine, is described. With aldehydes, these azadienes participate in hetero-Diels-Alder reactions with the in situ generated enamines. The stereoselectivity results from the approach of the dienophiles from the less hindered α-face of the steroid, with the pyrrolidine moiety endo and retention of the enamine trans geometry. This diastereoselective synthetic methodology led to a new class of chiral pentacyclic steroids. Interestingly, the studied steroidal scaffolds follow a different mechanistic pathway with cyclic ketones. They undergo a diastereoselective annulation reaction, under enamine catalysis, affording chiral hexacyclic steroids.

Novel d-Annulated Pentacyclic Steroids: Regioselective Synthesis and Biological Evaluation in Breast Cancer Cells

The acid-catalyzed cyclization of benzylidenes based on 16-dehydropregnenolone acetate (16-DPA) was studied. It was found that these compounds readily undergo regioselective interrupted Nazarov cyclization with trapping chloride ion and an efficient method of the synthesis of d-annulated pentacyclic steroids based on this reaction was proposed. The structures of the synthesized pentacyclic steroids were determined by NMR and X-ray diffraction. It was found that the reaction affords a single diastereomer, but the latter can crystallize as two conformers depending on the structure. Antiproliferative activity of synthesized compounds was evaluated against two breast cancer cell lines: MCF-7 and MDA-MB-231. All tested compounds showed relatively high antiproliferative activity. The synthetic potential of the protocol developed was illustrated by the gram-scale experiment.

Fe(iii)-Catalyzed synthesis of steroidal imidazoheterocycles as potent antiproliferative agents

An efficient and practical method has been developed for the synthesis of steroidal imidazoheterocycles via cost-effective and environmentally benign FeCl₃-catalyzed oxidative amination. A library of steroidal imidazo[1,2-a]pyridines was directly synthesized from readily available 2-aminopyridines and steroidal ketones in aerobic conditions. The synthesized compounds were screened for activity on human microsomal cytochrome P450s CYP7, CYP17 and CYP21. Antiproliferative activity of two lead compounds 3ia and 3la was additionally evaluated against the human MCF-7 (breast cancer), SKOV3 (ovarian cancer), and 22Rv1 (prostate cancer) cell lines. Steroidal imidazo[1,2-a]pyridine 3la which is a substrate molecule for CYP17A1 with IC₅₀ = 1.7 μM (MCF-7), 3.0 (SKOV3), and 6.0 μM (22Rv1) has proved to be more active than reference drug cisplatin.

Uses of Cyclohexan-1,3-dione for the Synthesis of Thiazole, Pyrazole, Thiophene, Isoxazole and Pyran Derivatives with Antitumor Activities

Background:

A wide range of thiazole, pyrazole and pyran derivatives gained special attention due to pharmacological activities especially therapeutic activities. Many pharmacological drugs containing the thiazole and pyrazole nuclei are known in the market.

Methods:

The 2-arylidencyclohexan-1,3-dione 3a-c were the key starting compounds for many heterocyclic reactions to produce substituted heterocyclic derivatives.

Results:

Antiproliferative activities of the produced compounds against six cancer cell lines A549, HT-29, MKN-45, U87MG, SMMC-7721 and H460 were measured in which the compounds showed high inhibition. The most promising compounds were tested against tyrosine kinases (c-Kit, Flt-3, VEGFR-2, EGFR, and PDGFR). Structure-Activity Relationship (SAR) was rationalized by assessing the varying structural features of the molecules. In addition, the most active compounds were selected for Pim-1 inhibition.

Conclusion:

Thirty compounds were synthesized. Ten of them (3a, 3c, 5a, 5c, 7a, 10f, 11a, 13c, 16a and 16c) were the most active compounds for selected cancer cell lines. Compounds 3c, 5c, 7a, 10f, 13c and 16c showed high inhibition toward the tyrosine kinases while compounds 3c, 5c and 10f were the most potent to inhibit Pim-1.

Discovery of chalcone-modified estradiol analogs as antitumour agents that Inhibit tumour angiogenesis and epithelial to mesenchymal transition

Angiogenesis plays an essential role in tumourigenesis and tumour progression, and anti-angiogenesis therapies have shown promising antitumour effects in solid tumours. 2-Methoxyestradiol (2ME2), an endogenous metabolite of estradiol, has been regarded as a potential antitumour agent mainly targeting angiogenesis. Here we synthesized a novel series of chalcones based on 2-methoxyestradiol and evaluated their potential activities against tumours. Compound 11e was demonstrated to have potent antiangiogenic activity. Further studies showed that 11e suppressed tumour growth in human breast cancer (MCF-7) xenograft models without obvious side effects. Evaluation of the mechanism revealed that 11e targeted the epithelial to mesenchymal transition (EMT) process in MCF-7 cells and inhibited HUVEC migration and then contributed to hindrance of angiogenesis. Thus, 11e may be a promising antitumour agent with excellent efficacy and low toxicity.