Rosmarinic Acid from Orthosiphon aristatus Potentially Targets Estrogen Receptor-Alpha in Breast Cancer: In-silico Study

Cryptotanshinone (CPT) has been demonstrated to inhibit proliferation and mammalian target of rapamycin (mTOR) pathway in MCF‐7 breast cancer cells. However, the same results are unable to be repeated in MDA‐MB‐231 cells. Given the main difference of oestrogen receptor α (ERα) between two types of breast cancer cells, It is possibly suggested that CPT inhibits mTOR pathway dependent on ERα in breast cancer. CPT could significantly inhibit cell proliferation of ERα‐positive cancer cells, whereas ERα‐negative cancer cells are insensitive to CPT. The molecular docking results indicated that CPT has a high affinity with ERα, and the oestrogen receptor element luciferase reporter verified CPT distinct anti‐oestrogen effect. Furthermore, CPT inhibits mTOR signalling in MCF‐7 cells, but not in MDA‐MB‐231 cells, which is independent on binding to the FKBP12 and disrupting the mTOR complex. Meanwhile, increased expression of phosphorylation AKT and insulin receptor substrate (IRS1) induced by insulin‐like growth factor 1 (IGF‐1) was antagonized by CPT, but other molecules of IGF‐1/AKT/mTOR signalling pathway such as phosphatase and tensin homolog (PTEN) and phosphatidylinositol‐4,5‐bisphosphate 3‐kinase (PI3K) were negatively affected. Finally, the MCF‐7 cells transfected with shERα for silencing ERα show resistant to CPT, and p‐AKT, phosphorylation of p70 S6 kinase 1 (p‐S6K1) and eukaryotic initiation factor 4E binding protein 1 (4E‐BP1) were partially recovered, suggesting ERα is required for CPT inhibition of mTOR signalling. Overall, CPT inhibition of mTOR is dependent on ERα in breast cancer and should be a potential anti‐oestrogen agent and a natural adjuvant for application in endocrine resistance therapy.

BackgroundBreast cancer is the most common cancer in women worldwide. More than 70% of breast cancers are estrogen receptor (ER) alpha positive. Compared with ER alpha-negative breast cancer, which is more aggressive and has a shorter survival time, ER alpha-positive breast cancer could benefit from endocrine therapy. Selective estrogen receptor modulators, such as tamoxifen, are widely used in endocrine therapy. Approximately half of ER alpha-positive breast cancer patients will eventually develop endocrine resistance, making it a major clinical challenge in therapy. Thus, decoding the throughput of estrogen signaling, including the control of ER alpha expression and stability, is critical for the improvement of breast cancer therapeutics.MethodsTRIM3 and ER alpha protein expression levels were measured by western blotting, while the mRNA levels of ER alpha target genes were measured by RT–PCR. A CCK-8 assay was used to measure cell viability. RNA sequencing data were analyzed by Ingenuity Pathway Analysis. Identification of ER alpha signaling activity was accomplished with luciferase assays, RT–PCR and western blotting. Protein stability assays and ubiquitin assays were used to detect ER alpha protein degradation. Ubiquitin-based immunoprecipitation assays were used to detect the specific ubiquitination modification on the ER alpha protein.ResultsIn our current study, we found that TRIM3, an E3 ligase, can promote ER alpha signaling activity and breast cancer progression. TRIM3 depletion inhibits breast cancer cell proliferation and migration, while unbiased RNA sequencing data indicated that TRIM3 is required for the activity of estrogen signaling on the -genome-wide scale. The immunoprecipitation assays indicated that TRIM3 associates with ER alpha and promotes its stability, possibly by inducing K63-linked polyubiquitination of ER alpha. In conclusion, our data implicate a nongenomic mechanism by which TRIM3 stabilizes the ER alpha protein to control ER alpha target gene expression linked to breast cancer progression.ConclusionOur study provides a novel posttranslational mechanism in estrogen signaling. Modulation of TRIM3 expression or function could be an interesting approach for breast cancer treatment.Graphical abstract2noEgdU1b5aSV4mMoG9UypVideo abstract

Estrogen receptor alpha (ERα), which has been detected in over 70% of breast cancer cases, is a driving factor for breast cancer growth. For investigating the underlying genes and networks regulated by ERα in breast cancer, RNA-seq was performed between ERα transgenic MDA-MB-231 cells and wild type MDA-MB-231 cells. A total of 267 differentially expressed genes (DEGs) were identified. Then bioinformatics analyses were performed to illustrate the mechanism of ERα. Besides, by comparison of RNA-seq data obtained from MDA-MB-231 cells and microarray dataset obtained from estrogen (E2) stimulated MCF-7 cells, an overlap of 126 DEGs was screened. The expression level of ERα was negatively associated with metastasis and EMT in breast cancer. We further verified that ERα might inhibit metastasis by regulating of VCL and TNFRSF12A, and suppress EMT by the regulating of JUNB and ID3. And the relationship between ERα and these genes were validated by RT-PCR and correlation analysis based on TCGA database. By PPI network analysis, we identified TOP5 hub genes, FOS, SP1, CDKN1A, CALCR and JUNB, which were involved in cell proliferation and invasion. Taken together, the whole-genome insights carried in this work can help fully understanding biological roles of ERα in breast cancer.

Design, synthesis, bioevaluation, DFT, docking, and molecular dynamic simulation for selected novel 1,3,4-Oxadiazole - indole derivatives hybrid against estrogen receptor alpha

The estrogen receptor alpha (ERα) plays an important role in breast development and pro-proliferation signal activation in the normal and cancerous breast. The ERα inhibitors were potentially active as cytotoxic agents against breast cancer. This study was conducted in order to find Asymmetrical Hexahydro-2H-Indazole Analogs of Curcumin (AIACs) as hits of ERα inhibitor. A training set of 17 selected ERα inhibitors was used to create 10 pharmacophore models using LigandScout 4.2. The pharmacophore models were validated using 383 active compounds as positive data and 20674 decoys as negative data obtained from DUD.E. Model 2 was found as the best pharmacophore model and consisted of three types of pharmacophore features, viz. one hydrophobic, one hydrogen bond acceptor, and aromatic interactions. Model 2 was utilized for ligand-based virtual screening 186 of AIACs, AMACs, intermediates, and Mannich base derivative compounds. The hits obtained were further screened using molecular docking, analyzed using drug scan, and tested for its synthesis accessibility. Fourteen compounds were fulfilled as hits in pharmacophore modeling, in which 10 hits were selected by molecular docking, but only seven hits met Lipinski’s rule of five and had medium synthesis accessibility. In conclusion, seven compounds were suggested to be potentially active as ERα inhibitors and deserve to be synthesized and further investigated.

Background: Human estrogen receptor alpha (ERα), which is known to play a role in mediating cell proliferation, metastasis, and resistance to apoptosis, is one of the targets of breast cancer therapies. Alpha mangostin (AM) is an active xanthone compound from Garcinia mangostana L. which has activity as an ERα inhibitor. Objectives: This research aims to predict the pharmacokinetic and toxicity, and to study the molecular interactions of AM derivatives with the ERα using computer-aided simulation approaches through molecular docking, molecular dynamic, and pharmacophore screening to develop novel anti-breast cancer agents. Methods: Marvinsketch and Chimera programs were used to design and optimize the structure of AM and its derivatives. For screening the pharmacokinetic and toxicity profiles, the PreADMET web was used. The AutoDockTools 1.5.6 and LigandScout 4.4.3 Advanced software were used to conduct the molecular docking simulation and pharmacophore screening, respectively, while the molecular dynamic simulation was performed using AMBER 16. The results were visualized by Biovia Discovery Studio. Results: Molecular docking using Autodock showed that FAT10 derivate has lower binding free energy (ΔG) (-12.04 kcal/mol) than AM (-8.45 kcal/mol) when docking to ERα and both performed the same hydrogen bond with Thr347. These support the results of the MMPBSA calculation on dynamic simulation which shows FAT10 (-58.4767 kcal/mol) has lower ΔG than AM (-42.7041 kcal/mol) and 4-OHT (- 49.0821 kcal/mol). The pharmacophore screening results also showed that FAT10 fitted the pharmacophore with a fit score of 47.08. Conclusion: From the results, it can be suggested that FAT10 has promising activity as ERα antagonist. Further in vitro and in vivo experiments should be carried out to support these in silico studies.

Breast cancer is the second leading contributor to the age-standardized mortality rate, for both sexes and all ages worldwide. In Europe and the United States, it is the second leading cause of mortality, with an incidence rate of about 2.6 million cases per year. Noscapine, a well-known alkaloid used as a cough suppressant, demonstrated anti-tumor effects by triggering apoptosis in various cancer cell lines and has the potential to become another ally against breast, ovarian, colon, and gastric cancer, among other types of malignancy. Apoptosis plays a crucial role in the treatment of cancer. Noscapine affected BAX, CASP8, CASP9, NFKBIA, and RELA gene and protein expression in the MCF-7 and MDA-MB-231 cell lines. Gene expression was higher in tumor than in normal tissue, including the BAX expression levels in lung, ovary, endometrium, colon, stomach, and glioblastoma patients; BCL2L1 expression in endometrium, colon, and stomach patients; CASP8 gene expression levels in lung, endometrium, colon, stomach, and glioblastoma patients; RELA in colon, stomach, and glioblastoma patients; and NFKBIA in glioblastoma patients. It can be concluded that noscapine affected genes and proteins related to apoptosis in cancer cell lines and several types of cancer patients.

Background: The role of estrogen receptor alpha (ERα) in breast cancer has been studied extensively, and its protein expression is prognostic and a primary determinant of endocrine sensitivity; however, much less is known about the role of ERß. In vitro studies demonstrate a tumor suppressive function for ERß, and we have recently implicated a role for ERα in sensitizing ERα expressing breast cancer cells to the anti-estrogenic effects of endoxifen. However, the in vivo relevance of ERα remains unclear due to conflicting reports. Here, we provide evidence that some of this controversy may be explained by variability in antibody specificity. In addition, we describe the development and characterization of a novel, highly specific monoclonal antibody and provide data regarding ERα expression in human breast cancers. Methods: Five commercially available ERα antibodies were screened for their sensitivity and specificity using western blotting, immunoprecipitation, immunofluorescence and immunohistochemistry in known ERα negative and positive cell lines as well as in normal human tissue samples. A novel monoclonal ERα antibody (C10) was developed and characterized in the same manner. Following identification of two specific antibodies, ERα expression was assessed in 66 breast tumors collected prior to adjuvant therapy. Samples were scored separately for nuclear and cytoplasmic staining. Results: In depth analysis of commercially available ERα antibodies reveled that the majority were non-specific with substantial cross-reactivity to ERα . Only one commercial antibody (PPG5/10), which solely recognizes full-length ERß, and our newly developed monoclonal antibody, which recognizes full-length and all 4 ERα variants, were determined to be sensitive and specific for ERα expression. These same two antibodies resulted in strong staining for endogenous levels of ERα protein in normal prostate tissue by immunohistochemistry. We further assessed these two antibodies in a set of breast tumors. Preliminary analysis revealed significant differences for ERα positivity between these two antibodies. Based on nuclear staining, 92% of tumors were ERα positive using the PPG5/10 antibody while only 34% were positive with C10. Approximately 50% of all tumors exhibited cytoplasmic staining with both antibodies. Conclusions: Our studies demonstrate that the majority of commercially available ERα antibodies are either non-specific or insensitive for the detection of ERα via immunohistochemistry. The present data call into question the relevance of prior studies which tested the association between clinical outcome and ERα expression and demonstrate the need to further analyze the role of ERα in breast cancer using highly specific and validated antibodies. While both the PPG5/10 and C10 antibodies are highly specific for ERß, the significant discrepancy in nuclear staining between them in breast tumors may be due to changes in epitope availability as a result of post-translational processing. Our newly developed C10 antibody could provide additional discriminatory features which may be useful in predicting response to therapy and/or associations with other clinicopathological factors and such studies are currently underway. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-25.

Recently dynein light chain 1 (DLC1), a cytoskeleton signaling component, has been shown to interact with and transactivate estrogen receptor-alpha (ER), leading to increased expression of ER target genes and growth stimulation of breast cancer cells. However, the molecular mechanism by which DLC1 regulates the ER pathway remains poorly understood. To gain insights into the putative mechanism, here we set out to identify novel DLC1-interacting proteins. We identified KIBRA, a WW domain- and a glutamic acid stretch-containing protein, as a DLC1-binding protein and showed that it interacts with DLC1 both in vitro and in vivo. We found that KIBRA-DLC1 complex is recruited to ER-responsive promoters. We also found that KIBRA-DLC1 interaction is mandatory for the recruitment and transactivation functions of ER or DLC1 to the target chromatin. Finally we found that KIBRA interacts with histone H3 via its glutamic acid-rich region and that such interaction might play a mechanistic role in conferring an optimal ER transactivation function as well as the proliferation of ligand-stimulated breast cancer cells. Together these findings indicate that DLC1-KIBRA interaction is essential for ER transactivation in breast cancer cells.

Estrogen receptor alpha (ERα) plays a crucial role in breast cancer progression, making it a key target for selective estrogen receptor modulators (SERMs). While Raloxifene has demonstrated therapeutic efficacy, resistance and limited bioactivity in some cases necessitate the development of novel ERα inhibitors with improved pharmacological profiles. A computational drug discovery approach integrating molecular docking, molecular dynamics (MD) simulations, and quantitative structure-activity relationship (QSAR) modeling was employed to design and evaluate new ERα inhibitors. Molecular docking was performed using Glide (XP mode) to predict ligand binding affinity and interaction patterns, while MD simulations over 100 ns assessed the stability and conformational dynamics of the protein-ligand complexes. A QSAR model was developed using a dataset of 1,231 compounds from ChEMBL, incorporating XGBoost regression with optimized hyperparameters for robust predictive performance. Compounds 3b, 3a, and 4a showed notable binding affinities (−9.319, −9.121, and −8.867 kcal/mol, respectively) that are comparable to Raloxifene (−9.791 kcal/mol), suggesting their potential as effective ERα ligands primarily through pi-pi stacking with PHE-404 and hydrogen bonding with Glu 353. MD simulations demonstrated that 3a, 4a, and 4b maintained stable receptor interactions (RMSD < 2.0 Å), while 3e and 4e exhibited higher fluctuations, indicating weaker engagement. The QSAR model achieved high predictive accuracy (RMSE < 0.6, R² > 0.8), identifying NO₂ (3d), OMe (3c), and Cl (3b) substitutions as key structural features enhancing receptor binding. This study identifies 3b, 3d, and 4b as promising lead compounds with strong binding affinity, stability, and predicted estrogen receptor activity. These findings provide a basis for further experimental validation and structural refinement to develop next-generation SERMs for ERα-positive breast cancer therapy.

Many estrogen receptor alpha (ERα)-positive breast cancers initially respond to aromatase inhibitors (AIs), but eventually acquire resistance. Here, we report that serum- and glucocorticoid-inducible kinase 3 (SGK3), a kinase transcriptionally regulated by ERα in breast cancer, sustains ERα signaling and drives acquired AI resistance. SGK3 is up-regulated and essential for endoplasmic reticulum (EnR) homeostasis through preserving sarcoplasmic/EnR calcium ATPase 2b (SERCA2b) function in AI-resistant cells. We have further found that EnR stress response down-regulates ERα expression through the protein kinase RNA-like EnR kinase (PERK) arm, and SGK3 retains ERα expression and signaling by preventing excessive EnR stress. Our study reveals regulation of ERα expression mediated by the EnR stress response and the feed-forward regulation between SGK3 and ERα in breast cancer. Given SGK3 inhibition reduces AI-resistant cell survival by eliciting excessive EnR stress and also depletes ERα expression/function, we propose SGK3 inhibition as a potential effective treatment of acquired AI-resistant breast cancer.

O. gratissimum is one of the most common medicinal plants in every community in Nigeria. This plant has been presumed to be useful in the management of diseases including breast cancer, which is one the commonest cancers affecting women globally. Hence, this study aimed to computationally investigate the phytochemicals present in O. gratissimum by elucidate their binding dynamics against five selected molecular targets of breast cancer and predict their pharmacokinetics properties. Molecular docking, MMGBSA calculation and ADMET prediction were used. The results showed that isovitexin has the highest binding affinity of −9.11 kcal/mol and −9.80 kcal/mol for Human Epidermal Growth Factor Receptor 2 (HER2) and Epidermal Growth Factor Receptor (EGFR) respectively. Rosmarinic acid has the highest binding affinity of −12.15 kcal/mol for Phosphatidylinositol 3-kinase (PI3K), Nepetoidin A has the highest binding affinity of −9.14 kcal/mol for oestrogen receptor (ER), and Vitexin has the highest binding affinity of −12.90 kcal/mol for Progesterone receptor (PR). MMGBSA provided total binding energy that confirmed the stability of the complexes under physiological conditions. The ADMET profiles showed that O. gratissimum top phytochemicals identified would be safe for oral administration with no hepatoxicity. Overall, this study identified isovitexin, vitexin, rosmarinic acid, nepetoidin A and luteolin among others, as compounds that exhibit strong anti-cancer properties against breast cancer cells.

Metastasis tumor antigen 1 (MTA1), a novel candidate metastasis-associated gene, is known to increase the migration and invasion of various tumor cells in vitro. It also plays an important role in tumorigenesis and tumor aggressiveness of breast cancer. Estrogen receptor alpha (ERα) plays an important role in the etiology of breast cancer and has been widely accepted as a prognostic marker for breast cancer and a response predictor for endocrine therapy. The ERα gene methylation has been linked to the lack of ERα expression in breast cancer. The aim of the study is to assess the correlation between the ERα methylation and MTA1 expression in breast cancer and further to investigate whether the repressed ERα methylation can downregulate the expression of MTA1 in vitro. In general, we found ERα methylation had significant correlation with the MTA1 expression (p < 0.05) in female patients of breast cancer (n = 102) by methylation-specific polymerase chain reaction and immunohistochemistry. To gain a deeper insight into the molecular mechanism underlying the relation between MTA1 and ERα methylation, we treated the invasive breast cancer cell lines with the demethylating agent, found the downregulation of MTA1 protein expression, and mRNA with the unmethylation of ERα (p < 0.05). And the invasive ability of breast cancer cells was significantly positively associated with MTA1 expression. These unique findings have greatly extended our current knowledge about the relation between ERα methylation and MTA1 expression. These data strongly support the hypothesis that methylation is involved in the relation between MTA1 and ERα in breast cancer.

Estrogen receptor alpha (ERα) plays a vital role in the development and progression of breast cancer by regulating the expression of genes associated with cell proliferation in breast tissue. ERα inhibition is a key strategy in the prevention and treatment of breast cancer. Previous research modified chalcone compounds into pyrazoline benzenesulfonamide derivatives (Modifina) which show activity as an ERα inhibitor. This study aimed to design novel pyrazoline benzenesulfonamide derivatives (PBDs) as ERα antagonists using in silico approaches. Structure-based and ligand-based drug design approaches were used to create drug target molecules. A total of forty-five target molecules were initially designed and screened for drug likeness (Lipinski’s rule of five), cytotoxicity, pharmacokinetics and toxicity using a web-based prediction tools. Promising candidates were subjected to molecular docking using AutoDock 4.2.6 to evaluate their binding interaction with ERα, followed by molecular dynamics simulations using AMBER20 to assess complex stability. A pharmacophore model was also generated using LigandScout 4.4.3 Advanced. The molecular docking results identified PBD-17 and PBD-20 as the most promising compounds, with binding free energies (ΔG) of −11.21 kcal/mol and −11.15 kcal/mol, respectively. Both formed hydrogen bonds with key ERα residues ARG394, GLU353, and LEU387. MM-PBSA further supported these findings, with binding energies of −58.23 kJ/mol for PDB-17 and −139.46 kJ/mol for PDB-20, compared to −145.31 kJ/mol, for the reference compound, 4-OHT. Although slightly less favorable than 4-OHT, PBD-20 demonstrated a more stable interaction with ERα than PBD-17. Furthermore, pharmacophore screening showed that both PBD-17 and PBD-20 aligned well with the generated model, each achieving a match score of 45.20. These findings suggest that PBD-17 and PBD-20 are promising lead compounds for the development of a potent ERα inhibitor in breast cancer therapy.

Background: The tropical climate in Indonesia can potentially predispose to various diseases caused by mosquitoes, one of which is Dengue Hemorrhagic Fever (DHF). Prevention by eradication of mosquito larvae (with larvicide) and mosquito bites (with repellent) is a strategic countermeasure to control DHF disease vectors. Larvicide and synthetic repellent use also can cause the development of resistance against the larvicide and thereby hurt humans. Therefore, it is necessary to find natural alternatives that are safe and more effective. One plant that has potential as a natural larvicide and repellent is the cat's whisker white-purple variety (Orthosiphon aristatus). The main secondary metabolite groups in white-purple cat whiskers are flavonoids and phenolics, and both groups are thought to have potential as larvicide and repellent. Objective: This review aimed to analyze the potential of white-purple cat plants as larvicides and repellents. Methods: Journal searches in this review came from primary data sources on the internet. Journal searches were conducted using search engines such as Google Scholar, PubMed, and ScienceDirect. In this review, the prediction of the activity of the active compounds in cat's whiskers (sinensetin and rosmarinic acid) as larvicides was also carried out in an in silico study. Results: The rosmarinic acid and sinensetin contained in cat's whiskers plants have the potential as larvicide and repellent Conclusion: Based on the literature search, flavonoid, and phenolic compounds have potential as larvicides and repellent. The larvicide and repellent mechanisms of the two secondary metabolites are of concern because they can cause certain disorders in the central nervous system through skin absorption or breathing