Recent developments in steroidal and nonsteroidal aromatase inhibitors for the chemoprevention of estrogen-dependent breast cancer

Potential of covalently linked tamoxifen hybrids for cancer treatment: recent update

Cancer is a complex disease and the second leading cause of death globally, and breast cancer is still a leading cause of cancer death in women. Tamoxifen is the most commonly used drug for breast cancer (ER-positive) treatment and chemoprevention, saving the lives of millions of patients every year. In addition, the tamoxifen template has been explored extensively for the development of selective estrogen receptor modulators (SERMs) applicable in breast cancer, osteoporosis, and postmenopausal symptom treatment. Numerous anticancer drugs, including tamoxifen, are in use, but the complexity and heterogeneous nature of cancer complicate the effect of conventional targeted drugs, leading to adverse reactions and resistance. One of the significant approaches to overcome these shortcomings is drug hybrids, generated by covalently linking two or more active pharmacophores. These drug hybrids are remarkably effective in acting on multiple drug targets with higher selectivity and specificity. In recent years, several tamoxifen hybrids have been discovered as potential candidates for cancer treatment. The review highlights the recent progress in developing anticancer hybrids, including organometallic, fluorescent, photocaged, and novel ligand-based tamoxifen hybrids. It also demonstrates the significance of merging various pharmacophores with tamoxifen to produce more potent, precise, and effective anticancer agents. The study offers valuable knowledge to researchers working on cancer research with the hope of enhancing drug potency and reducing drug toxicity to improve cancer patients' lives.

Design, synthesis, in-silico studies and apoptotic activity of novel amide enriched 2-(1H)- quinazolinone derivatives

Cancer is a broad classification of diseases that can affect any organ or body tissue due to aberrant cellular proliferation for unknown reasons. Many present chemotherapeutic drugs are highly toxic and have little selectivity. Additionally, they lead to the development of medication resistance. Therefore, developing tailored chemotherapeutic drugs with minimal side effects and good selectivity is crucial for cancer treatment. 2-(1H)-Quinazolinone is one of the vital scaffold and anticancer activity is one of the prominent biological activities of this class. Here we report the novel set of amide-enriched 2-(1H)-quinazolinone derivatives (7a-j) and their apoptotic activity with the help of MTT assay method against four human cancer cell lines: PC3 (prostate cancer), DU-145 (prostate cancer), A549 (lung cancer), and MCF7 (breast cancer). When compared to etoposide, every synthetic test compound (7a-j) exhibited moderate to excellent activity. The IC50 values of the new amide derivatives (7a-j) varied from 0.07 ± 0.0061 μM to 10.8 ± 0.69 μM. While the positive control, etoposide, exhibited 1.97 ± 0.45 μM to 3.08 ± 0.135 μM range. Among the novel amide derivatives (7a-j), in particular, 7i and 7j showed strong apoptotic activity against MCF7; 7h showed against PC3, and 7g showed against DU-145. Molecular docking studies of test compounds (7a-j) with the EGFR tyrosine kinase domain (PDB ID: 1M17) protein provided the significant docking scores for each test compound (7a-j) (-9.00 to -9.67 kcal/mol). Additionally, DFT investigations and MD simulations validated the predictions of molecular docking. According to the findings of the ADME analysis, oral absorption by humans is anticipated to be higher than 85 % for all test compounds.

Targeting aromatase to restrain oestrogen production and developing efficacious interventions against ER-positive cancer

Being the most frequently diagnosed disease, breast cancer is mainly classified as ER+ cancers due to the detection of estrogen receptor (ER) expression. Irrespetive of the successes achieved in the treatment of ER+ cancers by the use of selective estrogen receptor modulator (SERM) drugs like tamoxifen, resistance to the drug is a major clinical obstacle. Working on alternative treatment approaches, here, on the basis of mode of action of aromatase for the conversion of androstenedione to oestrogen, a series of compounds was developed. Results of all the experiments performed with these compounds led to the identification of three highly potent compounds 5d, 5e and 7d with their IC50 61.0, 83.0 and 54.0 nM for aromatase. Indicating their effectiveness in the treatment of ER+ cancers, appreciable tumor growth inhibitory activities of these compounds were observed against breast cancer cell lines. Further, the physico-chemical experiments including plasma protein binding, HSA binding, kinetic studies, solubility, ADME properties and molecular modelling studies supported the drug like features of the compounds.

Design and Pharmacophore Study of Triazole Analogues as Aromatase Inhibitors

BACKGROUND

In current scenario breast cancer measured as one of the dangerous health issues. An effective therapeutic class of drug known as aromatase inhibitors (AIs) is dominant against estrogen receptorpositive breast cancer. However, there is an urgent need to create target-specific AIs with better anti-breast cancer profiles due to the increased toxicity and adverse effects related to currently existing anti-breast cancer drugs.

OBJECTIVES

In the present study, we have designed of 100 novel tiazole analogues as aromatase inhibitors their pharmacophoric features were explored.

METHOD

Molecular docking was applied to a series of 4-substituted-1, 2, 3-triazoles containing letrozole for their aromatase inhibitory effects. The aromatase inhibitory activity of the compound in a series varies in the range of (IC50 = 0.008-31.26 μM). A hydrogen atom positioned at R1 of the triazole ring in compound (01) was responsible for the most potent compound (IC50 = 0.008 μM) in the series of 28 compounds as compared to letrozole. The self-organizing molecular field study was used to assess the molecular characteristics and biological activities of the compounds. The four models were developed using PLS and MLR methods. The PLS method was good for statistical analysis. The letrozole scaffold-based 100 compounds were designed by selecting an effective pharmacophore responsible for aromatase inhibitory activity. The designed compound was placed on the previous model as a test set, and its IC50 values were calculated.

RESULT

Hydrogen bonds were established between the potent molecule (01) and the essential residues Met 374 and Arg 115, which were responsible for the aromatase-inhibiting action. Cross-validated q2 (0.6349) & noncross- validated r2 (0.7163) were discovered in the statistical findings as having reliable predictive power. Among 100 designed compounds, seven compounds showed good aromatase inhibitory activities.

CONCLUSION

The additional final SOMFA model created for the interactions between the aromatase and the triazole inhibitors may be helpful for future modification and enhancement of the inhibitors of this crucial enzyme.

Green Approach Toward Triazole Forming Reactions for Developing Anticancer Drugs

Compounds containing triazole have many significant applications in the dye and ink industry, corrosion inhibitors, polymers, and pharmaceutical industries. These compounds possess many antimicrobial, antioxidant, anticancer, antiviral, anti-HIV, antitubercular, and anticancer activities. Several synthetic methods have been reported for reducing time, minimizing synthetic steps, and utilizing less hazardous and toxic solvents and reagents to improve the yield of triazoles and their analogues synthesis. Among the improvement in methods, green approaches towards triazole forming biologically active compounds, especially anticancer compounds, would be very important for pharmaceutical industries as well as global research community. In this article, we have reviewed the last five years of green chemistry approaches on click reaction between alkyl azide and alkynes to install 1,2,3-triazole moiety in natural products and synthetic drug-like molecules, such as in colchicine, flavanone cardanol, bisphosphonates, thiabendazoles, piperazine, prostanoid, flavonoid, quinoxalines, C-azanucleoside, dibenzylamine, and aryl-azotriazole. The cytotoxicity of triazole hybrid analogues was evaluated against a panel of cancer cell lines, including multidrug-resistant cell lines.

Synthesis of 2-aminopropyl benzopyran derivatives as potential agents against triple-negative breast cancer

Synthesis of three series of 2-aminopropyl derivatives containing a benzopyran nucleus was performed to evaluate their performance against triple-negative breast cancer cell lines (MDA-MB-231 and MDA-MB-436) and normal breast epithelial cells (MCF10A). For the three series, the cytotoxic activity was as follows: N-methylated derivatives (tertiary amines) 5b, 6b, and 7b > secondary amine benzopyrans 5, 6, and 7 > quaternary amine salts 5c, 6c, and 7c > free phenolic derivatives 5a, 6a, and 7a. The structure-activity relationship showed the importance of the presence of an amine group and a p-fluorobenzyloxy substituent in the chromanol ring (IC50 values from 1.5 μM to 58.4 μM). In addition, 5a, 5b, 6a, and 7b displayed slight selectivity towards tumor cells. Compounds 5, 5a, 5b, 6, 6a, 6c, 7, and 7b showed apoptotic/necrotic effects due to, at least in part, an increase in reactive oxygen species generation, whereas 5b, 5c, 6b, 7a, and 7c caused cell cycle arrest in the G1 phase. Further cell-based mechanistic studies revealed that 5a, 6a, and 7b, which were the most promising compounds, downregulated the expression of Bcl-2, while 5b downregulated the expression of cyclins CCND1 and CCND2. Therefore, 2-aminopropyl benzopyran derivatives emerge as new hits and potential leads for developing useful agents against breast cancer.

Secosteroid thiosemicarbazides and secosteroid-1,2,4-triazoles as antiproliferative agents targeting breast cancer cells: Synthesis and biological evaluation

A convenient and selective approach to 13,17-secoestra-1,3,5(10)-trien-17-oic acid [N'-arylcarbothioamido]hydrazides and hybrid molecules containing secosteroid and 1,2,4-triazole fragments was disclosed and these novel types of secosteroids were screened for cytotoxicity against hormone-dependent human breast cancer cell line MCF-7. Most of secosteroid-1,2,4-triazole hybrids showed significant cytotoxic effect comparable or superior to that of the reference drug cisplatin. Hit secosteroid-1,2,4-triazole hybrids 4b and 4h were characterized by high cytotoxicity and good selectivity towards MCF-7 breast cancer cells. PARP cleavage (marker of apoptosis) and ERα and cyclin D1 downregulation were discovered in MCF-7 cells treated with lead secosteroid-1,2,4-triazole hybrid 4b. The synthesized secosteroids may be considered as new promising anticancer agents.

New 1,2,3-Triazole/1,2,4-triazole Hybrids as Aromatase Inhibitors: Design, Synthesis, and Apoptotic Antiproliferative Activity

A novel series of 1,2,3-triazole/1,2,4-triazole hybrids 5a, 5b, and 6a-i was designed and synthesized as antiproliferative agents targeting aromatase enzymes. The antiproliferative activity of the new hybrids against four cancer cells was studied using Erlotinib as a control. Compounds 6a and 6b demonstrated the highest antiproliferative activity among these hybrids, with GI50 values of 40 nM and 35 nM, respectively. Compound 6b was the most potent derivative, with a GI50 of 35 nM, comparable to Erlotinib's GI50 of 33 nM. Compound 6b inhibited all cancer cell lines with comparable efficacy to Erlotinib. Compounds 5a, 5b, and 6a-i were tested for inhibitory action against aromatase as a potential target for their antiproliferative activity. Results revealed that compounds 6a and 6b were the most potent aromatase inhibitors, with IC50 values of 0.12 ± 0.01 µM and 0.09 ± 0.01 µM, respectively, being more potent than the reference Ketoconazole (IC50 = 2.6 ± 0.20 µM) but less potent than Letrozole (IC50 = 0.002 ± 0.0002). These findings indicated that compounds 6a and 6b had significant aromatase inhibitory action and are potential antiproliferative candidates. The findings were further linked to molecular docking investigations, which gave models of strong interactions with the aromatase domain for inhibitors with high binding scores.

A hydrophobic deep eutectic solvent-based vortex-assisted liquid-liquid microextraction applied for doping control of aromatase inhibitors from equine urine

Aromatase inhibitors (AIs) can indirectly cause increased testosterone in animals, which leads to the improvement of the athletic ability of horses. For the protection of horses and the consideration of fair competition, AIs were listed as prohibited drugs by the Federation Equestre Internationale (FEI). There were several disadvantages using traditional pretreatment methods before analyzing these drugs from biological samples. A rapid and green pretreatment method has been developed by utilizing the hydrophobic deep eutectic solvent (DES)-based vortex-assisted liquid-liquid microextraction (DES-VALLME) followed by ultra-high performance liquid chromatography tandem triple-quadrupole mass spectrometry (UHPLC-MS/MS) technique for the efficient extraction and sensitive detection of AIs in equine urine samples. The combination of menthol and 4-fluorophenol in a molar ratio 1:4 was chosen as the optimum composition of DES for extracting AIs. Under the optimum conditions, only 80 μL of DES, 1 mL equine urine and 2 min were expended. An external standard calibration method was utilized for determination, and a linear relationship was achieved with a concentration range of 0.02-4000 ng mL-1 (r2 ≥ 0.9983). The limits of detection of the method based on a signal-to-noise ratio of 3 were 0.01-4 ng mL-1. The accuracy recoveries ranged from 94.9% to 113.4% within the intra-day and inter-day relative standard deviations of less than 9.1%. Compared with traditional extraction methods, the DES-VALLME method had the advantages of rapidity, simplicity, efficiency, low toxicity, and low cost. This method has potential and possessed brilliant prospects for doping control.

Synthesis, Structural Investigations, DNA/BSA Interactions, Molecular Docking Studies, and Anticancer Activity of a New 1,4-Disubstituted 1,2,3-Triazole Derivative

We report herein a new 1,2,3-triazole derivative, namely, 4-((1-(3,4-dichlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-hydroxybenzaldehyde, which was synthesized by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The structure of the compound was analyzed using Fourier transform infrared spectroscopy (FTIR), 1H NMR, 13C NMR, UV-vis, and elemental analyses. Moreover, X-ray crystallography studies demonstrated that the compound adapted a monoclinic crystal system with the P21/c space group. The dominant interactions formed in the crystal packing were found to be hydrogen bonding and van der Waals interactions according to Hirshfeld surface (HS) analysis. The volume of the crystal voids and the percentage of free spaces in the unit cell were calculated as 152.10 Å3 and 9.80%, respectively. The evaluation of energy frameworks showed that stabilization of the compound was dominated by dispersion energy contributions. Both in vitro and in silico investigations on the DNA/bovine serum albumin (BSA) binding activity of the compound showed that the CT-DNA binding activity of the compound was mediated via intercalation and BSA binding activity was mediated via both polar and hydrophobic interactions. The anticancer activity of the compound was also tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using human cell lines including MDA-MB-231, LNCaP, Caco-2, and HEK-293. The compound exhibited more cytotoxic activity than cisplatin and etoposide on Caco-2 cancer cell lines with an IC50 value of 16.63 ± 0.27 μM after 48 h. Annexin V suggests the induction of cell death by apoptosis. Compound 3 significantly increased the loss of mitochondrial membrane potential (MMP) levels in Caco-2 cells, and the reactive oxygen species (ROS) assay proved that compound 3 could induce apoptosis by ROS generation.

Ferrozoles: Ferrocenyl derivatives of letrozole with dual effects as potent aromatase inhibitors and cytostatic agents

In the treatment of hormone-dependent cancers, aromatase inhibitors (AI) are receiving increased attention due to some undesirable effects such as the risk of endometrial cancer and thromboembolism of SERMs (selective estrogen receptor modulators). Letrozole is the most active AI with 99% aromatase inhibition. Unfortunately, this compound also exhibits some adverse effects such as hot flashes and fibromyalgias. Therefore, there is an urgent need to explore new types of AIs that retain the same-or even increased-antitumor ability. Inspired by the letrozole structure, a set of new derivatives has been synthesized that include a ferrocenyl moiety and different heterocycles. The derivative that contains a benzimidazole ring, namely compound 6, exhibits a higher aromatase inhibitory activity than letrozole and it also shows potent cytostatic behavior when compared to other well-established aromatase inhibitors, as demonstrated by dose-response, cell cycle, apoptosis and time course experiments. Furthermore, 6 promotes the inhibition of cell growth in both an aromatase-dependent and -independent fashion, as indicated by the study of A549 and MCF7 cell lines. Molecular docking and molecular dynamics calculations on the interaction of 6 or letrozole with the aromatase binding site revealed that the ferrocene moiety increases the van der Waals and hydrophobic interactions, thus resulting in an increase in binding affinity. Furthermore, the iron atom of the ferrocene fragment can form a metal-acceptor interaction with a propionate fragment, and this results in a stronger coupling with the heme group-a possibility that is consistent with the strong aromatase inhibition of 6.

Targeting the formation of estrogens for treatment of hormone dependent diseases-current status

Local formation and action of estrogens have crucial roles in hormone dependent cancers and benign diseases like endometriosis. Drugs that are currently used for the treatment of these diseases act at the receptor and at the pre-receptor levels, targeting the local formation of estrogens. Since 1980s the local formation of estrogens has been targeted by inhibitors of aromatase that catalyses their formation from androgens. Steroidal and non-steroidal inhibitors have successfully been used to treat postmenopausal breast cancer and have also been evaluated in clinical studies in patients with endometrial, ovarian cancers and endometriosis. Over the past decade also inhibitors of sulfatase that catalyses the hydrolysis of inactive estrogen-sulfates entered clinical trials for treatment of breast, endometrial cancers and endometriosis, with clinical effects observed primarily in breast cancer. More recently, inhibitors of 17beta-hydroxysteroid dehydrogenase 1, an enzyme responsible for formation of the most potent estrogen, estradiol, have shown promising results in preclinical studies and have already entered clinical evaluation for endometriosis. This review aims to provide an overview of the current status of the use of hormonal drugs for the major hormone-dependent diseases. Further, it aims to explain the mechanisms behind the -sometimes- observed weak effects and low therapeutic efficacy of these drugs and the possibilities and the advantages of combined treatments targeting several enzymes in the local estrogen formation, or drugs acting with different therapeutic mechanisms.

Synthesis, antiproliferative evaluation and in silico studies of a novel steroidal spiro morpholinone

Estrogens play a pivotal role in the development of estrogen-dependent breast cancer and other hormone-dependent disorders. A common strategy to overcome the pathological effects of estrogens is the use of aromatase inhibitors (AIs), which bind to the enzyme and prevent the union with the natural substrate, decreasing the amount of estrogens produced. Several AIs have been developed, including inhibitors with a steroidal backbone and a nitrogen heterocycle in their structure. Encouraged by the notable results presented by current and clinical steroidal drugs, herein we present the synthesis of a steroidal spiro morpholinone derivative as a plausible aromatase inhibitor. The morpholinone derivative was synthesized over a six-step methodology starting from estrone. The title compound and its hydroxychloroacetamide derivative precursor were evaluated for their antiproliferative profile against estrogen-dependent and independent solid tumor cell lines: A549, HBL-100, HeLa, SW1573, T-47D and WiDr. Both compounds exhibited a potent antiproliferative activity in the micromolar range against the six cancer cell lines, with the hydroxychloroacetamide derivative precursor being a more potent inhibitor (GI₅₀ = 0.25-2.4 µM) than the morpholinone derivative (GI₅₀ = 2.0-11 µM). Furthermore, both compounds showed, in almost all cases, better GI₅₀ values than the steroidal anticancer drugs abiraterone and galeterone. Docking simulations of the derivatives were performed in order to explain the experimental biological activity. The results showed interactions with the iron heme (derivative 3) and important residues of the steroidal binding-site (Met374) for the inhibition of human aromatase. A correlation was found between in vitro assays and the score obtained from the molecular docking study.

Therapeutic significance of molecular hybrids for breast cancer research and treatment

Worldwide, breast cancer is still a leading cause of cancer death in women. Indeed, over the years, several anti-breast cancer drugs have been developed; however, the complex heterogeneous nature of breast cancer disease reduces the applicability of conventional targeted therapies with the upsurge in side effects and multi-drug resistance. Molecular hybrids generated by a combination of two or more active pharmacophores emerged as a promising approach in recent years for the design and synthesis of anti-breast cancer drugs. The hybrid anti-breast cancer molecules are well known for their several advantages compared to the parent moiety. These hybrid forms of anti-breast cancer molecules demonstrated remarkable effects in blocking different pathways contributing to the pathogenies of breast cancer and improved specificity. In addition, these hybrids are patient compliant with reduced side effects and multi-drug resistance. The literature revealed that molecular hybrids are applied to discover and develop novel hybrids for various complex diseases. This review article highlights the recent progress (∼2018-2022) in developing molecular hybrids, including linked, merged, and fused hybrids, as promising anti-breast cancer agents. Furthermore, their design principles, biological potential, and future perspective are discussed. The provided information will lead to the development of novel anti-breast cancer hybrids with excellent pharmacological profiles in the future.

Design, synthesis, modeling studies and biological evaluation of pyrazole derivatives linked to oxime and nitrate moieties as nitric oxide donor selective COX-2 and aromatase inhibitors with dual anti-inflammatory and anti-neoplastic activities

Two new series of pyrazole derivatives 10a-f and 11a-f with selective COX-2 inhibition pharmacophore and oxime/nitrate moieties as NO donor moiety were designed, synthesized and tested for anti-inflammatory, cytotoxic activities and NO release. Compounds 10c, 11a, 11e were more selective for COX-2 isozyme (S.I. = 25.95, 22.52 and 21.54 respectively) in comparison to celecoxib (S.I. = 21.41). Regarding anti-cancer activity, all synthesized compounds were screened by the National Cancer Institute (NCI), Bethesda, USA for anticancer activity against 60 human cancer cell lines representing the following cancer types: leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast cancers. Compounds 10c, 11a, 11e were found to be the most potent inhibitors on breast, ovarian and melanoma cell lines (MCF-7, IGROV1 and SK-MEL-5), compound 11a causing 79 % inhibition in case of MCF-7, 78.80 % inhibition in case of SK-MEL-5 and unexpected cell growth -26.22 % inhibition in case of IGROV1 (IC₅₀ = 3.12, 4.28, 4.13 μM respectively). On the other hand, compounds 10c and 11e showed lower inhibition on the same cell lines with IC₅₀ = 3.58, 4.58, 4.28 μM respectively for 10c, IC₅₀ = 3.43, 4.73, 4.43 μM respectively for 11e. Furthermore, DNA-flow cytometric analysis showed that compound 11a induces cell cycle arrest at G2/M phase leading to cell proliferation inhibition and apoptosis. Additionally, these derivatives examined against F180 fibroblasts to investigate their selectivity indexes. The pyrazole derivative with internal oxime 11a was the most potent compound against most used cell lines especially MCF-7, IGROV1 and SK-MEL-5 (IC₅₀ = 3.12, 4.28, 4.13 μM respectively) with 4.82-fold selectivity towards MCF-7 than F180 fibroblasts. Moreover, oxime derivative 11a showed potent aromatase inhibitory activity (IC₅₀ 16.50 μM) when compared with reference compound letrozole (IC₅₀ 15.60 μM). All compounds 10a-f and 11a-f released NO in a slow rate (0.73-3.88 %) and the six derivatives 10c, 10e, 11a, 11b, 11c and 11e were the highest NO releasers (3.88, 2.15, 3.27, 2.27, 2.55 and 3.74 % respectively). Herein structure based and ligand based studies were implemented to under stand and evaluate the compounds activity for further in vivo and preclinical studies. Docking mode of final designed compounds with celecoxib (ID: 3LN1) represented that their triazole ring adopted as the core aryl in Y shaped structure. Regarding aromatase enzyme inhibition, docking was carried out with ID: 1 M17. The internal oxime series was more active as anticancer because of their ability to form extra HBs with receptor cleft.

Phytochemicals with Chemopreventive Activity Obtained from the Thai Medicinal Plant Mammea siamensis (Miq.) T. Anders.: Isolation and Structure Determination of New Prenylcoumarins with Inhibitory Activity against Aromatase

With the aim of searching for phytochemicals with aromatase inhibitory activity, five new prenylcoumarins, mammeasins K (1), L (2), M (3), N (4), and O (5), were isolated from the methanolic extract of Mammea siamensis (Miq.) T. Anders. flowers (fam. Calophyllaceae), originating in Thailand. The stereostructures of 1–5 were elucidated based on their spectroscopic properties. Among the new compounds, 1 (IC₅₀ = 7.6 µM) and 5 (9.1 µM) possessed relatively strong inhibitory activity against aromatase, which is a target of drugs already used in clinical practice for the treatment and prevention of estrogen-dependent breast cancer. The analysis through Lineweaver–Burk plots showed that they competitively inhibit aromatase (1, Ki = 3.4 µM and 5, 2.3 µM). Additionally, the most potent coumarin constituent, mammea B/AB cyclo D (31, Ki = 0.84 µM), had a competitive inhibitory activity equivalent to that of aminoglutethimide (0.84 µM), an aromatase inhibitor used in therapeutics.

Design and prediction of novel pyrazole derivatives as potential anti-cancer compounds based on 2D-2D-QSAR study against PC-3, B16F10, K562, MDA-MB-231, A2780, ACHN and NUGC cancer cell lines

Despite the decades of scientific studies for developing promising new therapies, cancer remains a major cause of illness and mortality, worldwide. Several cancer types are the major topic of research in drug discovery programs due to their global incidence cases and growing frequency. In the present study, using two different statistical approaches PCA (principal component analysis) and PLS (partial least squares), six 2D-QSAR (quantitative structure activity relationship) models have been developed for the set of compounds retrieved against seven cancer cell lines vizPC-3, B16F10, K562, MDA-MB-231, A2780, and ACHN. For the creation and validation of 2D-QSAR models, OECD (Organization for Economic Co-operation and Development) requirements have been strictly followed. All of the generated 2D-QSAR models produce a significant and high correlation coefficient value with several other statistical parameters. Moreover, developed 2D-QSAR models have been used for activity predictions of in-house synthesized 63 pyrazole derivatives compounds. Precisely, most statistically significant and accepted2D-QSAR model generated for each cancer cell line has been used to predict the pIC₅₀ value (anti-cancer activity) of all 63 synthesized pyrazole derivatives. Furthermore, designing of novel pyrazole derivatives has been carried out by substituting the essential functional groups based on the best derived 2D-QSAR models for each cancer cell line, more precisely, based on the most significant molecular descriptors with enhanced anti-cancer activity. Finally, the prediction of the new designed molecules reveals higher pIC₅₀ than the standard compounds.

Synthesis of New Pyrimidine-Triazole Derivatives and Investigation of Their Anticancer Activities

Aromatase inhibitors are the most used anticancer drug group in breast cancer cases. The development of resistance in cancer patients over time and the side effects of existing drugs make the need for new and effective agents permanent. In this study, 10 novel pyrimidine-triazole derivatives were synthesized and their anticancer activities were investigated. Compounds  5c  and  5g  showed inhibitor activity against MCF-7 cell line with IC 50 =1.573±0.020; 3.698±0.056 µM value, respectively.  As a result of  in vitro  aromatase enzyme inhibition test, compounds  5c  and  5g  were exhibited significant activity with IC 50 =0.082±0.007 µM and IC50=0.198±0.015 µM, respectively. Estimated physicochemical parameters were calculated using the online SwissADME program for all compounds. Interaction modes of the compounds  5c  and  5g  were investigated against aromatase enzyme by means of docking studies. As a result of the studies, the importance of the triazole ring for aromatase inhibition has been understood.

Exploration of structural requirements for azole chemicals towards human aromatase CYP19A1 activity: Classification modeling, structure-activity relationships and read-across study

Human aromatase, also called CYP19A1, plays a major role in the conversion of androgens into estrogens. Inhibition of aromatase is an important target for estrogen receptor (ER)-responsive breast cancer therapy. Use of azole compounds as aromatase inhibitors is widespread despite their low selectivity. A toxicological evaluation of commonly used azole-based drugs and agrochemicals with respect to CYP19A1is currently requested by the European Union- Registration, Evaluation, Authorization and Restriction of Chemicals (EU-REACH) regulations due to their potential as endocrine disruptors. In this connection, identification of structural alerts (SAs) is an effective strategy for the toxicological assessment and safe drug design. The present study describes the identification of SAs of azole-based chemicals as guiding experts to predict the aromatase activity. Total 21 SAs associated with aromatase activity were extracted from dataset of 326 azole-based drugs/chemicals obtained from Tox21 library. A cross-validated classification model having high accuracy (error rate 5%) was proposed which can precisely classify azole chemicals into active/inactive toward aromatase. In addition, mechanistic details and toxicological properties (agonism/antagonism) of azoles with respect to aromatase were explored by comparing active and inactive chemicals using structure-activity relationships (SAR). Lastly, few structural alerts were applied to form chemical categories for read-across applications.

Sulfonamide derivatives as potential anti-cancer agents and their SARs elucidation

Currently, the arise of drug resistance and undesirable off-target effects of anti-cancer agents are major challenges for cancer treatment, which energizes medicinal chemists to develop more anti-cancer agents with high efficiency and low toxicity continuously. Sulfonamide derivatives are a class of promising compounds with diverse biological activities including anti-cancer, and parts of them have been marketed for cancer therapy, such as Belinostat, ABT-199 and Amsacrine. In this review, we summed up the recent advances of sulfonamide derivatives as potential anti-cancer agents based on the anti-cancer targets, such as aromatase, carbonic anhydrase (CA), anti-apoptotic B-cell lymphoma-2 (Bcl-2) proteins, topoisomerase and phosphatidylinositol 3-kinase (PI3K), and elucidated the corresponding structure-activity relationships (SARs) of most sulfonamide derivatives. We hope this review could provide a clear insight for medicinal chemists in the rational design of more potent and bio-target specific anti-cancer agents.

An Update on Pharmacological Relevance and Chemical Synthesis of Natural Products and Derivatives with Anti SARS-CoV-2 Activity

Natural products recognized traditionally as a vital source of active constituents in pharmacotherapy. The COVID-19 infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly transmissible, pathogenic, and considered an ongoing global health emergency. The emergence of COVID-19 globally and the lack of adequate treatment brought attention towards herbal medicines, and scientists across the globe instigated the search for novel drugs from medicinal plants and natural products to tackle this deadly virus. The natural products rich in scaffold diversity and structural complexity are an excellent source for antiviral drug discovery. Recently the investigation of several natural products and their synthetic derivatives resulted in the identification of promising anti SARS-CoV-2 agents. This review article will highlight the pharmacological relevance and chemical synthesis of the recently discovered natural product and their synthetic analogs as SARS-CoV-2 inhibitors. The summarized information will pave the path for the natural product-based drug discovery of safe and potent antiviral agents, particularly against SARS-CoV-2.

Investigations on the Degradation of the Bile Salt Cholate via the 9,10-Seco-Pathway Reveals the Formation of a Novel Recalcitrant Steroid Compound by a Side Reaction in Sphingobium sp. Strain Chol11

Bile salts such as cholate are steroid compounds from the digestive tracts of vertebrates, which enter the environment upon excretion, e.g., in manure. Environmental bacteria degrade bile salts aerobically via two pathway variants involving intermediates with Δ^1,4- or Δ^4,6-3-keto-structures of the steroid skeleton. Recent studies indicated that degradation of bile salts via Δ^4,6-3-keto intermediates in Sphingobium sp. strain Chol11 proceeds via 9,10-seco cleavage of the steroid skeleton. For further elucidation, the presumptive product of this cleavage, 3,12β-dihydroxy-9,10-seco-androsta-1,3,5(10),6-tetraene-9,17-dione (DHSATD), was provided to strain Chol11 in a co-culture approach with Pseudomonas stutzeri Chol1 and as purified substrate. Strain Chol11 converted DHSATD to the so far unknown compound 4-methyl-3-deoxy-1,9,12-trihydroxyestra-1,3,5(10)7-tetraene-6,17-dione (MDTETD), presumably in a side reaction involving an unusual ring closure. MDTETD was neither degraded by strains Chol1 and Chol11 nor in enrichment cultures. Functional transcriptome profiling of zebrafish embryos after exposure to MDTETD identified a significant overrepresentation of genes linked to hormone responses. In both pathway variants, steroid degradation intermediates transiently accumulate in supernatants of laboratory cultures. Soil slurry experiments indicated that bacteria using both pathway variants were active and also released their respective intermediates into the environment. This instance could enable the formation of recalcitrant steroid metabolites by interspecies cross-feeding in agricultural soils.

Design, Synthesis and Biological Evaluation of Aromatase Inhibitors Based on Sulfonates and Sulfonamides of Resveratrol

A library of sulfonate and sulfonamide derivatives of Resveratrol was synthesized and tested for its aromatase inhibitory potential. Interestingly, sulfonate derivatives were found to be more active than sulfonamide bioisosteres with IC₅₀ values in the low micromolar range. The sulfonate analogues 1b–c and 1j exhibited good in vitro antiproliferative activity on the MCF7 cell line, evidenced by MTT and LDH release assays. Structure–activity relationships suggested that electronic and lipophilic properties could have a different role in promoting the biological response for sulfonates and sulfonamides, respectively. Docking studies disclosed the main interactions at a molecular level of detail behind the observed inhibition of the more active compounds whose chemical stability has been evaluated with nano-liquid chromatography. Finally, 1b–c and 1j were highlighted as sulfonates to be further developed as novel and original aromatase inhibitors.

Imidazoles as Potential Anticancer Agents: An Update on Recent Studies

Nitrogen-containing heterocyclic rings are common structural components of marketed drugs. Among these heterocycles, imidazole/fused imidazole rings are present in a wide range of bioactive compounds. The unique properties of such structures, including high polarity and the ability to participate in hydrogen bonding and coordination chemistry, allow them to interact with a wide range of biomolecules, and imidazole-/fused imidazole-containing compounds are reported to have a broad spectrum of biological activities. This review summarizes recent reports of imidazole/fused imidazole derivatives as anticancer agents appearing in the peer-reviewed literature from 2018 through 2020. Such molecules have been shown to modulate various targets, including microtubules, tyrosine and serine-threonine kinases, histone deacetylases, p53-Murine Double Minute 2 (MDM2) protein, poly (ADP-ribose) polymerase (PARP), G-quadraplexes, and other targets. Imidazole-containing compounds that display anticancer activity by unknown/undefined mechanisms are also described, as well as key features of structure-activity relationships. This review is intended to provide an overview of recent advances in imidazole-based anticancer drug discovery and development, as well as inspire the design and synthesis of new anticancer molecules.

The predictive potential of Neuronatin for neoadjuvant chemotherapy of breast cancer

BACKGROUND

Neuronatin (NNAT) determined by immunohistochemistry is a negative prognostic biomarker for breast cancer, independent of the major clinicopathological markers.

OBJECTIVE

Here, we investigated whether NNAT is also a predictive biomarker for pathological remission after neoadjuvant chemotherapy.

METHODS

One hundred and four breast cancer patients, treated with systemic neoadjuvant chemotherapy were included in this retrospective study. NNAT was detected in formaldehyde fixed, paraffin embedded primary cancer tissue by immunohistochemistry and an immuno-reactive score (IRS) determined. Pathological remission was scored according to Sinn and by evaluation of cytopathic effects. NNAT-IRS was correlated with clinicopathological parameters as well as relapse free and overall survival and for pathological remission after neoadjuvant therapy.

RESULTS

NNAT IRS was an independent prognostic marker for relapse free and overall survival and the time from diagnosis to the "tumor-free" state. NNAT IRS was associated with Luminal-A tumors and correlated slightly negative with age and lymph-node metastasis. There was no significant correlation of NNAT-IRS with Sinn's remission score, but with cytopathic effects of chemotherapy.

CONCLUSIONS

We confirmed the prognostic impact of NNAT-IRS in an independent cohort of neoadjuvantly treated patients. Additionally, a correlation with a score for pathological remission under systemic neoadjuvant chemotherapy for breast cancer was found.

A review on diverse heterocyclic compounds as the privileged scaffolds in non-steroidal aromatase inhibitors

Breast cancer, emerging malignancy is common among women due to overexpression of estrogen. Estrogens are biosynthesized from androgens by aromatase, a cytochrome P450 enzyme complex, and play a pivotal role in stimulating cell proliferation. Therefore, deprivation of estrogen by blocking aromatase is considered as the effective way for the inhibition and treatment of breast cancer. In recent years, various non-steroidal heterocyclic functionalities have been extensively developed and studied for their aromatase inhibition activity. This review provides information about the structural-activity relationship of heterocycles (Type II) towards aromatase. This aids the medicinal chemist around the significance of different heterocyclic moieties and helps to design potent aromatase inhibitors.

1,2,3,4-Tetrahydroisoquinoline (THIQ) as privileged scaffold for anticancer de novo drug design

Introduction: Cancer is a dreadful disorder that is emerging as one of the leading causes of mortality across the globe. The complex tumor environment, supplemented with drawbacks of the existing drugs, has made it a global health concern. The Tetrahydroisoquinoline (THIQ) ring holds an important position in medicinal chemistry due to its wide range of pharmacological properties. Several THIQ based natural products have been previously explored for their antitumor properties, making it a vital scaffold for anticancer drug design.Areas covered: This review article addresses the potential of THIQ as anticancer agents. Various medicinal chemistry strategies employed for the design and development of THIQ analogs as inhibitors or modulators of relevant anticancer targets have been discussed in detail. Moreover, the common strategies employed for the synthesis of the core scaffold are also highlighted.Expert opinion: Evidently, THIQs have tremendous potential in anticancer drug design. Some of these analogs exhibited potent activity against various cancer molecular targets. However, there are some drawbacks, such as selectivity that need addressing. The synthetic ease for constructing the core scaffold complimented with its reactivity makes it ideal for further structure-activity relationship studies. For these reasons, THIQ is a privileged scaffold for the design and development of novel anticancer agents.

Developing Novel Anticancer Drugs for Targeted Populations: An Update

BACKGROUND

Due to higher failure rates, lengthy time and high cost of the traditional de novo drug discovery and development process, the rate of opportunity to get new, safe and efficacious drugs for the targeted population, including pediatric patients with cancer, becomes sluggish.

OBJECTIVES

This paper discusses the development of novel anticancer drugs focusing on the identification and selection of targeted anticancer drug development for the targeted population.

METHODS

Information presented in this review was obtained from different databases, including PUBMED, SCOPUS, Web of Science, and EMBASE. Various keywords were used as search terms.

RESULTS

The pharmaceutical companies currently are executing drug repurposing as an alternative means to accelerate the drug development process that reduces the risk of failure, time and cost, which take 3-12 years with almost 25% overall probability of success as compared to de novo drug discovery and development process (10- 17 years) which has less than 10% probability of success. An alternative strategy to the traditional de novo drug discovery and development process, called drug repurposing, is also presented.

CONCLUSION

Therefore, to continue with the progress of developing novel anticancer drugs for the targeted population, identification and selection of target to specific disease type is important. Considering the aspects of the age of the patient and the disease stages such as each cancer types are different when we study the disease at a molecular level. Drug repurposing technique becomes an influential alternative strategy to discover and develop novel anticancer drug candidates.

The race to treat COVID-19: Potential therapeutic agents for the prevention and treatment of SARS-CoV-2

The unforeseen emergence of coronavirus disease 2019 (COVID-19), a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the Wuhan province of China in December 2019, subsequently its abrupt spread across the world has severely affected human life. In a short span of time, COVID-19 has sacked more than one million human lives and marked as a severe global pandemic, which is drastically accountable for the adverse effect directly to the human society, particularly the health care system and the economy. The unavailability of approved and effective drugs or vaccines against COVID-19 further created conditions more adverse and terrifying. To win the war against this pandemic within time there is a desperate need for the most adequate therapeutic treatment, which can be achieved by the collaborative research work among scientists worldwide. In continuation of our efforts to support the scientific community, a review has been presented which discusses the structure and the activity of numerous molecules exhibiting promising SARS-CoV-2 and other CoVs inhibition activities. Furthermore, this review offers an overview of the structure, a plausible mechanism of action of SARS-CoV-2, and crucial structural features substantial to inhibit the primary virus-based and host-based targets involved in SARS-CoV-2 treatment. We anticipate optimistically that this perspective will provide the reader and researcher’s better understanding regarding COVID-19 and pave the path in the direction of COVID-19 drug discovery and development paradigm.

Design, synthesis and biological evaluation of imidazole and triazole-based carbamates as novel aromatase inhibitors

In the search for novel aromatase inhibitors, a series of triazole and imidazole-based carbamate derivatives were designed and synthesized. Final compounds were thus evaluated against human aromatase by in vitro kinetic experiments in a fluorimetric assay in comparison with letrozole. The effect of most active derivatives 13a and 15c was then evaluated in vitro on the human breast cancer cell line MCF7 by MTT assay, cytotoxicity assay (LDH release) and cell cycle analysis, revealing a dose-dependent inhibition profile of cell viability and low micromolar IC₅₀ values. In addition, docking simulations were also carried out to elucidate at a molecular level of detail the binding modes adopted to target human aromatase.

Normal breast epithelial MCF-10A cells to evaluate the safety of carbon dots

The human normal breast cell line MCF-10A is being widely used as a model in toxicity studies due to its structural similarity to the normal human mammary epithelium. Over the years, application of carbon dots (C-dots) in biomedicine has been increasing due to their photoluminescence properties, biocompatibility, biosafety and possible applications in bioimaging and as drug carriers. In this work we prepared three different C-dots from the same set of carbon and nitrogen precursors (citric acid and urea, respectively) via three distinct bottom-up synthetic routes and their safety was tested against the normal breast cell line MCF-10A. The characterization results demonstrated a similar size range and composition for all the C-dots. The MCF-10A cells were treated with different concentrations of C-dots for 24, 48 and 72 h to evaluate the cell viability over time. For the 24 h incubation, there were no significant decreases in the viability of the MCF-10A cells. For the 48 h treatment, there was a significant decrease in the viability of the cells treated with calcination-based C-dots, but without significant cellular viability changes for microwave and hydrothermal-based C-dots. For 72 h, cells treated with hydrothermal-based C-dots have the most promising viability profile. Also, compared with paclitaxel, these C-dots have a safety profile very close to that of an antineoplastic in non-tumor cells. Our results suggest that these new C-dots have potential as imaging candidates or biosensing tools as well as drug carriers, and further investigation in animal models is needed for future application in medicine.

In silico study for prediction of novel bioactivities of the endophytic fungal alkaloid, mycoleptodiscin B for human targets

Mycoleptodiscin B is a natural product extracted from the endophytic fungus Mycoleptodiscus sp. found in Sri Lanka and Panama with experimentally unexplored activities for human targets. In this study, a computational methodology was applied to determine druggable targets of mycoleptodiscin B. According to the computational toxicity and pharmacokinetics assessment, mycoleptodiscin B was proven to be a suitable drug candidate. Druggable targets for this compound, aromatase, acidic plasma glycoprotein and androgen receptor, were predicted using reverse docking. A two-step validation of those targets was performed using conventional molecular docking and molecular dynamic (MD) simulations, resulting in aromatase being determined as the potential therapeutic target. Based on molecular mechanics/Generalized Born Surface Area (GBSA) free energies and ligand stability inside the active site cavity during its 120 ns MD run, it can be concluded that mycoleptodiscin B is a potent aromatase inhibitor and could be subjected to further in vitro and in vivo experiments in the drug development pipeline. Consequently, natural product chemists can quickly identify the hidden medicinal properties of their miracle compounds using the computational approach applied in this research.

Quinoxaline Derivatives as Antiviral Agents: A Systematic Review

Background: In recent decades, several viruses have jumped from animals to humans, triggering sizable outbreaks. The current unprecedent outbreak SARS-COV-2 is prompting a search for new cost-effective therapies to combat this deadly pathogen. Suitably functionalized polysubstituted quinoxalines show very interesting biological properties (antiviral, anticancer, and antileishmanial), ensuring them a bright future in medicinal chemistry. Objectives: Focusing on the promising development of new quinoxaline derivatives as antiviral drugs, this review forms part of our program on the anti-infectious activity of quinoxaline derivatives. Methods: Study compiles and discusses recently published studies concerning the therapeutic potential of the antiviral activity of quinoxaline derivatives, covering the literature between 2010 and 2020. Results: A final total of 20 studies included in this review. Conclusions: This review points to a growing interest in the development of compounds bearing a quinoxaline moiety for antiviral treatment. This promising moiety with different molecular targets warrants further investigation, which may well yield even more encouraging results regarding this scaffold.

Recent progress in selective estrogen receptor downregulators (SERDs) for the treatment of breast cancer

Selective estrogen receptor downregulators (SERDs) are a novel class of compounds capable of reducing the ERα protein level and blocking ER activity. Therefore, SERDs are considered as a significant therapeutic approach to treat ER+ breast cancer in both early stage and more advanced drug-resistant cases. After the FDA approval of a steroidal drug, fulvestrant, as a SERD for the treatment of breast cancer in patients who have progressed on antihormonal agents, several molecules with diverse chemical structures have been rapidly developed, studied and evaluated for selective estrogen receptor downregulation activity. Here we compile the promising SERDs reported in recent years and discuss the chemical structure and pharmacological profile of the most potent compound of the considered series. Because of the availability of only a limited number of effective drugs for the treatment of breast cancer, the quest for a potent SERD with respectable activity and bioavailability is still ongoing. The goal of this article is to make available to the reader an overview of the current progress in SERDs and provide clues for the future discovery and development of novel pharmacological potent SERDs for the treatment of breast cancer.

Recent Development in Indole Derivatives as Anticancer Agents for Breast Cancer

BACKGROUND

Breast Cancer (BC) is the second most common cause of cancer related deaths in women. Due to severe side effects and multidrug resistance, current therapies like hormonal therapy, surgery, radiotherapy and chemotherapy become ineffective. Also, the existing drugs for BC treatment are associated with several drawbacks such as poor oral bioavailability, non-selectivity and poor pharmacodynamics properties. Therefore, there is an urgent need for the development of more effective and safer anti BC agents.

OBJECTIVE

This article explored in detail the possibilities of indole-based heterocyclic compounds as anticancer agents with breast cancer as their major target.

METHODS

Recent literature related to indole derivatives endowed with encouraging anti BC potential is reviewed. With special focus on BC, this review offers a detailed account of multiple mechanisms of action of various indole derivatives: aromatase inhibitor, tubulin inhibitor, microtubule inhibitor, targeting estrogen receptor, DNA-binding mechanism, induction of apoptosis, inhibition of PI3K/AkT/NFkB/mTOR, and HDAC inhibitors, by which these derivatives have shown promising anticancer potential.

RESULTS

Exhaustive literature survey indicated that indole derivatives are associated with properties of inducing apoptosis and disturbing tubulin assembly. Indoles are also associated with the inhibition of NFkB/mTOR/PI3K/AkT and regulation of estrogen-mediated activity. Furthermore, indole derivatives have been found to modulate critical targets such as topoisomerase and HDAC. These derivatives have shown significant activity against breast cancer cells.

CONCLUSION

In BC, indole derivatives seem to be quite competent and act through various mechanisms that are well established in case of BC. This review has shown that indole derivatives can further be explored for the betterment of BC chemotherapy. A lot of potential is still hidden which demands to be discovered for upgrading BC chemotherapy.

Pyridine and Pyrimidine Derivatives as Privileged Scaffolds in Biologically Active Agents

Pyridine and pyrimidine derivatives have received great interest in recent pharmacological research, being effective in the treatment of various malignancies, such as myeloid leukemia, breast cancer and idiopathic pulmonary fibrosis. Most of the FDA approved drugs show a pyridine or pyrimidine core bearing different substituents. The aim of this review is to describe the most recent reports in this field, with reference to the newly discovered pyridineor pyrimidine-based drugs, to their synthesis and to the evaluation of the most biologically active derivatives. The corresponding benzo-fused heterocyclic compounds, i.e. quinolines and quinazolines, are also reported.

Rational approaches of drug design for the development of selective estrogen receptor modulators (SERMs), implicated in breast cancer

Drug discovery and development have gained momentum due to the rational drug design by engaging computational tools and bioinformatics methodologies. Bioisosteric replacements and hybrid molecular approaches are the other inventive processes, used by medicinal chemists for the desired modifications of leads for clinical drug candidates. SERMs, ought to produce inhibitory activity in breast, uterus and agonist activity in other tissues, are beneficial for estrogen-like actions. ER subtypes α and β are hormone dependent modulators of intracellular signaling and gene expression, and development of ER selective ligands could be an effective approach for treatment of breast cancer. This report has critically investigated the possible designing considerations of SERMs, their in silico interactions, and potent pharmacophore generation approaches viz. indole, restricted benzothiophene [3, 2-b] indole, carborane, xanthendione, combretastatin A-4, organometallic heterocycles, OBHS-SAHA hybrids, benzopyranones, tetrahydroisoquinolines, Dig G derivatives and their specifications in drug design and development, to rationally improve the understanding in drug discovery. This also includes various strategies for the development of dual inhibitors for the management of antiestrogenic resistance.

Human cytochrome P450 enzymes 5-51 as targets of drugs and natural and environmental compounds: mechanisms, induction, and inhibition - toxic effects and benefits

Cytochrome P450 (P450, CYP) enzymes have long been of interest due to their roles in the metabolism of drugs, pesticides, pro-carcinogens, and other xenobiotic chemicals. They have also been of interest due to their very critical roles in the biosynthesis and metabolism of steroids, vitamins, and certain eicosanoids. This review covers the 22 (of the total of 57) human P450s in Families 5-51 and their substrate selectivity. Furthermore, included is information and references regarding inducibility, inhibition, and (in some cases) stimulation by chemicals. We update and discuss important aspects of each of these 22 P450s and questions that remain open.

Cytotoxicity of eupatorin in MCF-7 and MDA-MB-231 human breast cancer cells via cell cycle arrest, anti-angiogenesis and induction of apoptosis

Eupatorin has been reported with in vitro cytotoxic effect on several human cancer cells. However, reports on the mode of action and detail mechanism of eupatorin in vitro in breast cancer disease are limited. Hence, eupatorin's effect on the human breast carcinoma cell line MCF-7 and MDA-MB-231 was investigated. MTT assay showed that eupatorin had cytotoxic effects on MCF-7 and MDA-MB-231 cells but was non-toxic to the normal cells of MCF-10a in a time-dose dependent manner. At 24 h, the eupatorin showed mild cytotoxicity on both MCF-7 and MDA-MB-231 cells with IC50 values higher than 20 μg/mL. After 48 h, eupatorin at 5 μg/mL inhibited the proliferation of MCF-7 and MDA-MB-231 cells by 50% while the IC50 of MCF-10a was significantly (p < 0.05) high with 30 μg/mL. The concentration of eupatorin at 5 μg/mL induced apoptosis mainly through intrinsic pathway by facilitating higher fold of caspase 9 compared to caspase 8 at 48 h. The cell cycle profile also showed that eupatorin (5 μg/mL) exerted anti-proliferation activity with the cell cycle arrest of MCF-7 and MDA-MB-231 cells at sub Gθ/G1 in a time-dependent manner. In addition, wound healing assay showed an incomplete wound closure of scratched MDA-MB-231 cells, and more than 60% of the MDA-MB-231 cells were prevented to migrate and invade the membrane in the Boyden chamber after 24 h. Eupatorin also inhibited angiogenic sprouting of new blood vessels in ex vivo mouse aorta ring assay. In gene expression assay, eupatorin up-regulated pro-apoptotic genes such as Bak1, HIF1A, Bax, Bad, cytochrome c and SMAC/Diablo and blocked the Phospho-Akt pathway. In conclusion, eupatorin is a potent candidate to induce apoptosis and concurrently inhibit the invasion, migration and angiogenesis of MDA-MB-231 and MCF-7 cells through inhibition of Phospho-Akt pathway and cell cycle blockade.