Regulation of estrogen receptor signaling in breast carcinogenesis and breast cancer therapy

Therapeutic significance of long noncoding RNAs in estrogen receptor-positive breast cancer

About 70% of cases of breast cancer are compromised by Estrogen-positive breast cancer. Through its regulation of several processes, including cell proliferation, cell cycle progression, and apoptosis, Estrogen signaling plays a pivotal role in the genesis and progression of this particular kind of breast cancer. One of the best treatment strategies for treating Estrogen-positive breast cancer is blocking Estrogen signaling. However, patients' treatment failure is mainly caused by the emergence of resistance and metastases, necessitating the development of novel therapeutic targets. Numerous studies have shown long noncoding RNAs (lncRNAs) to play a role in Estrogen-mediated carcinogenesis. These lncRNAs interact with co-regulators and the Estrogen signaling cascade components, primarily due to Estrogen activation. Vimentin and E-cadherin are examples of epithelial-to-mesenchymal transition markers, and they regulate genes involved in cell cycle progression, such as Cyclins, to affect the growth, proliferation, and metastasis of Estrogen-positive breast cancer. Furthermore, a few of these lncRNAs contribute to developing resistance to chemotherapy, making them more desirable targets for enhancing results. Thus, to shed light on the creation of fresh approaches for treating this cancer, this review attempts to compile recently conducted studies on the relationship between lncRNAs and the advancement of Estrogen-positive breast cancer.

Structure-based virtual screening of anti-breast cancer compounds from Artemisia absinthium-insights through molecular docking, pharmacokinetics, and molecular dynamic simulations

Breast cancer is the world's second most frequent malignancy, with a significant mortality and morbidity rate. Nowadays, natural breast cancer medicine has piqued attention as disease-curing agent with low side effects. Herein, the leaf powder of Artemisia absinthium was extracted with ethanol, and GC-MS and LC-MS methods were employed to identify the phytocompounds. Using commercial software SeeSAR-9.2 and StarDrop, identified phytocompounds were docked with estrogen and progesterone breast cancer receptors as they promote breast cancer growth to find the binding affinity of the ligands, drugability, and toxicity. Hormone-mediated breast cancer accounts for about 80% of all cases of breast cancer. Cancer cells proliferate when estrogen and progesterone hormones are attached to these receptors. The molecular docking results demonstrated that 3',4',5,7-Tetrahydroxyisoflavanone (THIF) has stronger binding efficacy than standard drugs and other phytocompounds with -28.71 (3 hydrogen bonds) and -24.18 kcal/mol (6 hydrogen bonds) binding energies for estrogen and progesterone receptors, respectively. Pharmacokinetics and toxicity analysis were done to predict the drug-likeness of THIF which results in good drugability and less toxicity. The best fit THIF was subjected to a molecular dynamics simulation analysis by using Gromacs to analyze the conformational changes that occurred during protein-ligand interaction and found that, the structural changes were observed. The results from MD simulation and pharmacokinetic studies suggested that THIF can be expected that in vitro and in vivo research on this compound may lead to the development of a potent anti-breast cancer drug in the future.Communicated by Ramaswamy H. Sarma.

Forkhead Box Q1 is a novel regulator of autophagy in breast cancer cells

Forkhead Box Q1 (FoxQ1) transcription factor is overexpressed in luminal-type and basal-type human breast cancers when compared to normal mammary tissue. This transcription factor is best known for its role in promotion of breast cancer stem-like cells and epithelial to mesenchymal transition. The present study documents a novel function of FoxQ1 in breast cancer cells. Overexpression of FoxQ1 in basal-like SUM159 cells and luminal-type MCF-7 cells resulted in increased conversion of microtubule-associated protein light chain 3 beta-I (LC3B-I) to LC3B-II, which is a hallmark of autophagy. Autophagy induction by FoxQ1 overexpression was confirmed by visualization of LC3B puncta as well as by transmission electron microscopy. Expression profiling for genes implicated in autophagy regulation revealed upregulation of many genes, including ATG4B, ATG16L1, CTSS, CXCR4 and so forth but downregulation of BCL2L1, DRAM1, TNF, ULK2 and so forth by FoxQ1 overexpression in SUM159 cells. Western blot analysis confirmed upregulation of ATG4B and CXCR4 proteins by FoxQ1 overexpression in both SUM159 and MCF-7 cells. Chromatin immunoprecipitation assay revealed recruitment of FoxQ1 at the promoter of ATG4B. Pharmacological inhibition of ATG4B using S130 significantly increased apoptosis induction by DOX in empty vector transfected as well as FoxQ1 overexpressing SUM159 and MCF-7 cells but this effect was statistically significantly lowered by FoxQ1 overexpression indicating the protective role of FoxQ1 on apoptosis. Treatment of SUM159 cells with S130 and DOX enhanced LC3B-II level in both empty vector transfected cells and FoxQ1 overexpressing SUM159 cells but not in FoxQ1 overexpressing MCF-7 cells. In conclusion, FoxQ1 is a novel regulator of autophagy.

Structure-Based Multi-Targeted Molecular Docking and Dynamic Simulation of Soybean-Derived Isoflavone Genistin as a Potential Breast Cancer Signaling Proteins Inhibitor

Globally, breast cancer (BC), the second-biggest cause of cancer death, occurs due to unregulated cell proliferation leading to metastasis to other parts of the human organ. Recently, the exploration of naturally derived anticancer agents has become popular due to their fewer adverse effects. Among the natural products, soybean is a very well-known legume that contains important bioactive compounds such as diadazine, glycetin, genistein, and genistin. Therefore, keeping its therapeutic potential in mind, multi-targeted molecular docking and simulation studies were conducted to explore the potential role of soybean-derived isoflavone genistin against several breast cancer-signaling proteins (ER-alpha, ER-Beta, collapsin response mediator protein 2, CA 15-3, human epidermal growth factor receptor 2). A comparative study of the genistin-protein docked complex was explored to investigate its potential role in BC. The molecular binding energy (∆G) of the docked complex was calculated along with ADMET properties. The molecular docking score of genistin with ubiquitin-like protein activation complex-a type of Cancer Antigen (CA) 15.3 (PDB ID-2NVU, 5T6P, and 1YX8) showed the highest binding energy, ranging from -9.5 to -7.0 Kcal/mol, respectively. Furthermore, the highest docking scores of the complex were additionally put through molecular dynamics (MD) simulation analysis. MD simulations of the selected complex were performed at 100 ns to study the stability of the genistin-ubiquitin-like protein CA 15.3 complex, which appeared to be quite stable. Additionally, the ADMET study demonstrated that genistin complies with all drug-likeness standards, including Lipinski, Egan, Veber, Ghose, and Muegge. Therefore, based on the results, genistin can be considered as one of the potential drugs for the management and treatment of BC. In addition, the obtained results suggest that genistin could pave the way for new drug discovery to manage breast cancer and has potential in the development of nutraceuticals.

Innovative Thiosemicarbazones that Induce Multi-Modal Mechanisms to Down-Regulate Estrogen-, Progesterone-, Androgen- and Prolactin-Receptors in Breast Cancer

The estrogen receptor-α (ER-α) is a key driver of breast cancer (BC) and the ER-antagonist, tamoxifen, is a central pillar of BC treatment. However, cross-talk between ER-α, other hormone and growth factor receptors enables development of de novo resistance to tamoxifen. Herein, we mechanistically dissect the activity of a new class of anti-cancer agents that inhibit multiple growth factor receptors and down-stream signaling for the treatment of ER-positive BC. Using RNA sequencing and comprehensive protein expression analysis, we examined the activity of di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT) and di-2-pyridylketone-4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), on the expression and activation of hormone and growth factor receptors, co-factors, and key resistance pathways in ER-α-positive BC. DpC differentially regulated 106 estrogen-response genes, and this was linked to decreased mRNA levels of 4 central hormone receptors involved in BC pathogenesis, namely ER, progesterone receptor (PR), androgen receptor (AR), and prolactin receptor (PRL-R). Mechanistic investigation demonstrated that due to DpC and Dp44mT binding metal ions, these agents caused a pronounced decrease in ER-α, AR, PR, and PRL-R protein expression. DpC and Dp44mT also inhibited activation and down-stream signaling of the epidermal growth factor (EGF) family receptors, and expression of co-factors that promote ER-α transcriptional activity, including SRC3, NF-κB p65, and SP1. In vivo, DpC was highly tolerable and effectively inhibited ER-α-positive BC growth. Through bespoke, non-hormonal, multi-modal mechanisms, Dp44mT and DpC decrease the expression of PR, AR, PRL-R, and tyrosine kinases that act with ER-α to promote BC, constituting an innovative therapeutic approach.

Analysis of Essential Oils Components from Aromatic Plants Using Headspace Repellent Method against Aedes aegypti Mosquitoes

This research serves as the basis for developing essential oil-based repellent activity tests against Aedes aegypti mosquitoes. The method used for the isolation of essential oils was the steam distillation method. Virus-free Aedes aegypti mosquitoes were used as test animals by applying the 10% essential oil repellent on the arms of volunteers. The analysis of the essential oils activities and aromas' components was carried out using headspace repellent and GC-MS methods. Based on the results, the yields of essential oil from 5000 g samples for cinnamon bark, clove flowers, patchouli, nutmeg seed, lemongrass, citronella grass, and turmeric rhizome were 1.9%, 16%, 2.2%, 16.8%, 0.9%, 1.4%, and 6.8%, respectively. The activity test showed that the average repellent power of 10% essential oils, patchouli, cinnamon, nutmeg, turmeric, clove flowers, citronella grass, and lemongrass, was 95.2%, 83.8%, 71.4%, 94.7%, 71.4%, 80.4%, and 85%, respectively. Patchouli and cinnamon had the best average repellent power. Meanwhile, the aroma activities showed that the average repellent power of the patchouli oil was 96%, and the cinnamon oil was 94%. From the GC-MS analysis, nine components were identified in the patchouli essential oil aromas' with the highest concentration being patchouli alcohol (42.7%), Azulene, 1,2,3,5,6,7,8,8a-octahydro-1,4-dimethyl-7-(1-methylethenyl)-, [1S-(1α,7α,8aβ)] (10.8%), α-guaiene (9.22%), and seychellene (8.19%)., whereas using the GC-MS headspace repellent method showed that there were seven components identified in the patchouli essential oil aroma with a high concentration of the components, which were patchouli alcohol (52.5%), Seychellene (5.2%), and α-guaiene (5.2%). The analysis results of cinnamon essential oil using the GC-MS method showed that there were five components identified in the aroma, with E-cinnamaldehyde (73%) being the highest component, whereas using the GC-MS headspace repellent method showed that there were five components identified in the aroma, with highest concentrations of cinnamaldehyde (86.1%). It can be concluded that the chemical compounds contained in patchouli and cinnamon bark have the potential to be environmentally friendly repellents in controlling and preventing Aedes aegypti mosquitoes.

Evaluation of Salivary KCNJ3 mRNA Levels in Breast Cancer: A Case–control Study and in silico Analysis

Background:

Breast cancer (BC) is considered the most malignant and central cancer-related death among women worldwide. There is an essential need to discover new methods for developing noninvasive and low-cost diagnoses. The present study examines the expression of KCNJ3 which acts as a biomarker for detecting BC in the saliva of BC patients compared to controls.

Methods:

The mRNA expression level of KCNJ3 has been evaluated. Forty-three unstimulated whole saliva samples from BC patients and forty-three salivary samples from healthy controls were collected. The mRNA level was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, the protein-protein interaction network in which KCNJ3 is involved was obtained. In silico analysis was applied to predict the possible molecular mechanisms of KCNJ3 in BC development.

Results:

Differentially expressed KCNJ3 was statistically significant between BC patients and controls (p<0.001). The sensitivity and specificity of KCNJ3 mRNA in BC detection were 76.74% and 94.95%, respectively. Receiver operating characteristic (ROC) curve analysis of KCNJ3 mRNA revealed that Area under the curve (AUC) was 0.923 (95% Confidence Interval (CI): 0.866-0.979). AUCs of ROC curve analysis were 0.743 (95% CI: 0.536-0.951), 0.685 (95% CI: 0.445-0.925), and 0.583(95% CI: 0.343-0.823) for differentiation stage I from stage III, stage I to stage II and finally stage II from stage III, respectively. Furthermore, the GABAergic synapse signaling pathway was suggested as a potential pathway involved in BC development.

Conclusion:

Salivary levels of KCNJ3 could be considered a potential diagnostic biomarker with high sensitivity and specificity for BC detection.

Structure-guided design and development of cyclin-dependent kinase 4/6 inhibitors: A review on therapeutic implications

Cyclin-dependent kinase 6 (EC 2.7.11.22) play significant roles in numerous biological processes and triggers cell cycle events. CDK6 controlled the transcriptional regulation. A dysregulated function of CDK6 is linked with the development of progression of multiple tumor types. Thus, it is considered as an effective drug target for cancer therapy. Based on the direct roles of CDK4/6 in tumor development, numerous inhibitors developed as promising anti-cancer agents. CDK4/6 inhibitors regulate the G1 to S transition by preventing Rb phosphorylation and E2F liberation, showing potent anti-cancer activity in several tumors, including HR+/HER2- breast cancer. CDK4/6 inhibitors such as abemaciclib, palbociclib, and ribociclib, control cell cycle, provoke cell senescence, and induces tumor cell disturbance in pre-clinical studies. Here, we discuss the roles of CDK6 in cancer along with the present status of CDK4/6 inhibitors in cancer therapy. We further discussed, how structural features of CDK4/6 could be implicated in the design and development of potential anti-cancer agents. In addition, the therapeutic potential and limitations of available CDK4/6 inhibitors are described in detail. Recent pre-clinical and clinical information for CDK4/6 inhibitors are highlighted. In addition, combination of CDK4/6 inhibitors with other drugs for the therapeutic management of cancer are discussed.

Network pharmacology-based study to identify the significant pathways of Lentinula edodes against cancer

Lentinula edodes (LE) is known as a good food source with potent anticancer efficacy, but its active chemical compounds and pathways against cancer have not been revealed. This study was to uncover the active chemical constituents and pathways of LE against cancer through network pharmacology. The chemical compositions were recognized by gas chromatography-mass spectrometry (GC-MS) and filtered drug-like compounds (DLCs) by SwissADME. Targets related to filtered compounds were recognized by two public databases and the final overlapping targets were identified by Venn diagram. Then, protein-protein interaction (PPI) and pathway-target-compound (PTC) networks were built by RStudio. Ultimately, we recognized the key compounds and targets via molecular docking test (MDT). A total of 33 compounds from LE were accepted by Lipinski's rule were selected as DLCs. The 33 compounds were associated with 108 targets and a key target (cyclooxygenase2 [COX2]) was identified through PPI networks. Most significantly, inactivation of pathways in cancer and activation of peroxisome proliferator activated receptor signaling pathway were significant pathways of LE. On MDT, we identified a key compound (Indole, 2-methyl-3-phenyl) on COX2 related to inactivation of athways in cancer, additionally, the number of 6 ergostane steroids was associated with the two pathways might be dual efficacy to alleviate inflammation against cancer. Overall, 13 targets, 11 compounds, and 2 key pathways of LE were identified as the significant elements to treat cancer. Hence, this study shows therapeutic evidence to verify the promising clinical effect of LE on cancer, suggesting that LE might be an important mushroom against cancer. PRACTICAL APPLICATIONS: Lentinula edodes (LE) has been used widely in cuisine as well as alternative medicines, especially, for anticancer. The LE has rich nutritional compounds including proteins, vitamins, polyphenols, and glucans, however, most of which have a critical hurdle as poor bioavailability not to be applicable for pharmaceuticals. Its main cause is very hydrophilic property. Thus, we adopted GC-MS analysis to identify lipophilic compounds to enhance cell permeability involved in bioavailability. The compounds selected from LE were confirmed by Lipinski's rule for drug-like-compounds (DLCs). Then, we retrieved targets associated with DLCs, and multiple pathways, multiple targets, and multiple compounds against cancer on network-based analysis. In summary, our study reveals the medicinal value of LE on cancer based on the multicomponents. Overall, the aim of this work is to represent the pharmacological evidence to reveal the therapeutic efficacy of AC on cancer, suggesting that DLCs from AC might be alleviators to dampen cancer.

Epigenetic Factors as Etiological Agents, Diagnostic Markers, and Therapeutic Targets for Luminal Breast Cancer

Luminal breast cancer, an etiologically heterogeneous disease, is characterized by high steroid hormone receptor activity and aberrant gene expression profiles. Endocrine therapy and chemotherapy are promising therapeutic approaches to mitigate breast cancer proliferation and recurrence. However, the treatment of therapy-resistant breast cancer is a major challenge. Recent studies on breast cancer etiology have revealed the critical roles of epigenetic factors in luminal breast cancer tumorigenesis and drug resistance. Tumorigenic epigenetic factor-induced aberrant chromatin dynamics dysregulate the onset of gene expression and consequently promote tumorigenesis and metastasis. Epigenetic dysregulation, a type of somatic mutation, is a high-risk factor for breast cancer progression and therapy resistance. Therefore, epigenetic modulators alone or in combination with other therapies are potential therapeutic agents for breast cancer. Several clinical trials have analyzed the therapeutic efficacy of potential epi-drugs for breast cancer and reported beneficial clinical outcomes, including inhibition of tumor cell adhesion and invasiveness and mitigation of endocrine therapy resistance. This review focuses on recent findings on the mechanisms of epigenetic factors in the progression of luminal breast cancer. Additionally, recent findings on the potential of epigenetic factors as diagnostic biomarkers and therapeutic targets for breast cancer are discussed.

Identification of Diagnostic Markers for Breast Cancer Based on Differential Gene Expression and Pathway Network

Background: Breast cancer is the second largest cancer in the world, the incidence of breast cancer continues to rise worldwide, and women's health is seriously threatened. Therefore, it is very important to explore the characteristic changes of breast cancer from the gene level, including the screening of differentially expressed genes and the identification of diagnostic markers. Methods: The gene expression profiles of breast cancer were obtained from the TCGA database. The edgeR R software package was used to screen the differentially expressed genes between breast cancer patients and normal samples. The function and pathway enrichment analysis of these genes revealed significant enrichment of functions and pathways. Next, download these pathways from KEGG website, extract the gene interaction relations, construct the KEGG pathway gene interaction network. The potential diagnostic markers of breast cancer were obtained by combining the differentially expressed genes with the key genes in the network. Finally, these markers were used to construct the diagnostic prediction model of breast cancer, and the predictive ability of the model and the diagnostic ability of the markers were verified by internal and external data. Results: 1060 differentially expressed genes were identified between breast cancer patients and normal controls. Enrichment analysis revealed 28 significantly enriched pathways (p < 0.05). They were downloaded from KEGG website, and the gene interaction relations were extracted to construct the gene interaction network of KEGG pathway, which contained 1277 nodes and 7345 edges. The key nodes with a degree greater than 30 were extracted from the network, containing 154 genes. These 154 key genes shared 23 genes with differentially expressed genes, which serve as potential diagnostic markers for breast cancer. The 23 genes were used as features to construct the SVM classification model, and the model had good predictive ability in both the training dataset and the validation dataset (AUC = 0.960 and 0.907, respectively). Conclusion: This study showed that the difference of gene expression level is important for the diagnosis of breast cancer, and identified 23 breast cancer diagnostic markers, which provides valuable information for clinical diagnosis and basic treatment experiments.

Overexpression of FAM234B Predicts Poor Prognosis in Patients with Luminal Breast Cancer

Background

Family with sequence similarity 234 member B (FAM234B), a protein-coding gene, is mainly expressed in brain tissues. Its clinical significance and biological function in tumors, especially in breast cancer (BC), have not been elucidated.

Methods

We firstly investigated the expression pattern of FAM234B at the mRNA and protein levels using Oncomine, TCGA portal, GEPIA, TIMER, HPA, and UALCAN databases, then applied bc-GenExMiner to assess the associations between expression level of FAM234B and clinicopathological features of BC. Besides, we also verified the expression of FAM234B expression in clinical BC samples using qRT-PCR. Subsequently, GEPIA, bc-GenExMiner, and TIMER databases were used to analyze the prognostic significance of FAM234B in all BC and different molecular subtypes. Finally, we conducted co-expression analysis and gene set enrichment analysis (GSEA). Additionally, we explored the regulatory mechanism of FAM234B in BC.

Results

Both bioinformatics analysis and experimental verification confirmed that the FAM234B expression was significantly higher at the mRNA and protein levels in luminal BC tissues than in adjacent normal tissues. High FAM234B expression was significantly correlated with older age, estrogen receptor-positive, progesterone receptor-positive, human epidermal growth factor receptor 2-negative, wild-type p53, low Nottingham prognostic index, low Scarff-Bloom-Richardson grade, lymph node metastasis positivity, and high tumor stage. Moreover, survival analysis indicated that high FAM234B expression was significantly related to a worse prognosis in patients with luminal BC. GSEA indicated that FAM234B was positively related to membrane transport process and negatively associated with immune response function. Besides, mechanism exploration indicated that pseudogene HTR7P1 might act as endogenous RNA to compete with has-miR-1271-5p or has-miR-381-3p for binding to FAM234B, thereby upregulating the expression of FAM234B in luminal BC.

Conclusion

Our results suggest that FAM234B may be a candidate therapeutic target or prognostic marker for luminal breast cancer.

Cytotoxicity Of Chalcone Of Eugenia aquea Burm F. Leaves Against T47D Breast Cancer Cell Lines And Its Prediction As An Estrogen Receptor Antagonist Based On Pharmacophore-Molecular Dynamics Simulation

Background

The 2ʹ,4ʹ-dihydroxy-6-methoxy-3,5-3-dimethylchalcone (ChalcEA) isolated from Eugenia aquea Burm f. leaves has potential anticancer activity against human breast-adenocarcinoma cell lines (MCF-7) with an IC₅₀ value of 250 µM. However, its apoptotic activity on the T47D breast cancer cell lines which is involving caspase-3 has not been investigated.

Materials and methods

Therefore, this study aims to evaluate the cytotoxicity of ChalcEA on the T47D cell lines using the 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST) method and to predict its possible antagonistic activity on the human estrogen receptor alpha (hERα) using pharmacophore and molecular dynamics (MD) methods. The in vitro test of 10 synthesized ChalcEA derivatives was also performed as an insight into the further development of its structure as an anticancer agent.

Results

It is shown that ChalcEA has an IC₅₀ of 142.58 ± 4.6 µM against the hERα-overexpressed T47D breast cancer cell lines, indicating its possible mechanism of anticancer activity as an antagonist of hERα. Pharmacophore study showed that ChalcEA shares similar features with the known hERα antagonist, 4-hydroxytamoxifen (4-OHT), which has hydrogen bond donor (HBD), hydrogen bond acceptor (HBA), ring aromaticity (RA), and hydrophobicity (Hy) features. Molecular docking showed that ChalcEA formed hydrogen bonds with Glu353 and Arg394, and hydrophobic interactions in a similar manner with 4-OHT. Moreover, MD simulations showed that ChalcEA destabilized the conformation of His524, a remarkable behavior of a known hERa antagonist, including 4-OHT. Furthermore, the 10 best chalcone derivatives resulted from pharmacophore- and docking-based screening, were tested against the T47D cell lines. None of the derivatives have better activity than ChalcEA. It is suggested that the functional groups at the B-ring of ChalcEA are interesting to be further optimized in the next studies.

Conclusion

ChalcEA might act as an antagonist toward hERα, thus warranting further investigation as a potential anticancer agent.

Distinct Roles for BET Family Members in Estrogen Receptor α Enhancer Function and Gene Regulation in Breast Cancer Cells

The bromodomain family member proteins (BRD; BET proteins) are key coregulators for estrogen receptor alpha (ERα)-mediated transcriptional enhancers. The use of BRD-selective inhibitors has gained much attention as a potential treatment for various solid tumors, including ER-positive breast cancers. However, the roles of individual BET family members have largely remained unexplored. Here, we describe the role of BRDs in estrogen (E2)-dependent gene expression in ERα-positive breast cancer cells. We observed that chemical inhibition of BET family proteins with JQ1 impairs E2-regulated gene expression and growth in breast cancer cells. In addition, RNAi-mediated depletion of each BET family member (BRDs 2, 3, and 4) revealed partially redundant roles at ERα enhancers and for target gene transcription. Furthermore, we found a unique role of BRD3 as a molecular sensor of total BET family protein levels and activity through compensatory control of its own protein levels. Finally, we observed that BRD3 is recruited to a subset of ERα-binding sites (ERBS) that are enriched for active enhancer features, located in clusters of ERBSs likely functioning as "super enhancers," and associated with highly E2-responsive genes. Collectively, our results illustrate a critical and specific role for BET family members in ERα-dependent gene transcription. IMPLICATIONS: BRD3 is recruited to and controls the activity of a subset ERα transcriptional enhancers, providing a therapeutic opportunity to target BRD3 with BET inhibitors in ERα-positive breast cancers.

Recent nanotechnological interventions targeting PI3K/Akt/mTOR pathway: A focus on breast cancer

Breast cancer is the major cause of deaths in women worldwide. Detection and treatment of breast cancer at earlier stages of the disease has shown encouraging results. Modern genomic technologies facilitated several therapeutic options however the diagnosis of the disease at an advanced stage claim more deaths. Therefore more research directed towards genomics and proteomics into this area may lead to novel biomarkers thereby enhancing the survival rates in breast cancer patients. Phosphoinositide-3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway was shown to be hyperactivated in most of the breast carcinomas resulting in excessive growth, proliferation, and tumor development. Development of nanotechnology has provided many interesting avenues to target the PI3K/Akt/mTOR pathway both at the pre-clinical and clinical stages. Therefore, the current review summarizes the underlying mechanism and the importance of targeting PI3K/Akt/mTOR pathway, novel biomarkers and use of nanotechnological interventions in breast cancer.

Basic helix-loop-helix transcription factor Twist1 is a novel regulator of anterior gradient protein 2 homolog (AGR2) in breast cancer

Anterior gradient protein 2 homolog (AGR2) belongs to the disulfide isomerase family of endoplasmic reticulum proteins. Itis overexpressed in several types of solid tumors, including tumors of the prostate, lung, and pancreas. However, the role of AGR2 in breast cancer and the regulatory mechanisms underlying AGR2 protein expressionare not fullyunderstood. We demonstrated that AGR2 levels are increased under hypoxic conditions and in breast cancer tumors. Mechanistically, Twist1 binds to, and activates the AGR2 promoter via an E-box sequence. Under hypoxic conditions, the increased expression of ARG2 is attenuated when Twist1 levels are reduced by shRNA. Conversely, Twist1 overexpression fully reverses decreased AGR2 levels upon HIF-1α knockdown. Notably, AGR2 is required for Twist1-induced proliferation, migration, and invasion of breast cancer cells. Collectively, these findings extend our understanding of AGR2 regulation in breast cancer and may contribute to development of Twist1-AGR2 targeting therapeutics for breast cancer.

New dimensions in calix[4]pyrrole: the land of opportunity in supramolecular chemistry

The quest for receptors endowed with the selective complexation and detection of negatively charged species continues to receive substantial consideration within the scientific community worldwide. This study is encouraged by the utilization of anions in nature in a plethora of biological systems such as chloride channels and proteins and as polyanions for genetic information. The molecular recognition of anionic species is greatly interesting in terms of their favourable interactions. In this comprehensive review, in addition to giving accounts of some selected syntheses, we illustrated diverse applications ranging from molecular containers to ion transporters and drug carriers of a supramolecular receptor named calix[4]pyrrole. We believe that the present review may act as a catalyst in enhancing the novel applications of calix[4]pyrrole and its congeners in the other dimensions of science and technology.

The quest for receptors endowed with the selective complexation and detection of negatively charged species continues to receive substantial consideration within the scientific community worldwide.

Oestrogen Inhibits VEGF Expression And Angiogenesis In Triple-Negative Breast Cancer By Activating GPER-1

Triple-negative breast cancer (TNBC) is the most malignant type of breast cancer with ample vascularisation and high vascular endothelial growth factor (VEGF) expression. The sex steroid hormone oestrogen is involved in several cellular activities associated with TNBC regulation. However, the role of oestrogen in VEGF expression and angiogenesis in TNBC remains unclear. In this study, we found that treatment with 17β-oestradiol (E2) inhibited VEGF mRNA and protein expression in the TNBC cell lines MDA-MB-468 and MDA-MB-436. To further elaborate on the phenomenon of E2-regulated angiogenesis, we showed that conditioned medium from the TNBC cell line MDA-MB-468 treated with E2 inhibits the tube formation ability of human umbilical vein endothelial cells (HUVECs). Additionally, the G-protein-coupled oestrogen receptor-1 (GPER-1)-specific agonist G-1 has a function similar to that of E2. While G-15, the selective antagonist of GPER-1, notably reversed the inhibitory effects of E2 and G-1 on VEGF expression and tube formation, suggesting that GPER-1 is involved in the E2-induced angiogenesis suppression in TNBC cells. Moreover, E2 inhibited in vivo tumour growth and angiogenesis and reduced the expression levels of VEGF, NF-κB/p65, STAT3, and the endothelial marker CD34 in MDA-MB-468 xenograft tumours. Our findings provide important evidence that E2 can inhibit VEGF expression and angiogenesis in TNBC by activating GPER-1, offering additional insight into tumour angiogenesis and targets for drug intervention in TNBC.

Baicalein has protective effects on the 17β-estradiol-induced transformation of breast epithelial cells

Epidemiologic and systematic studies have indicated that flavonoid consumption is associated with a lower incidence of breast cancer. Baicalein is the primary flavonoid derived from the roots of Scutellaria baicalensis Georgi. In the current study, the long-term exposure of breast epithelial cells to 17β-estradiol (E2) was used to investigate the chemopreventive potential of baicalein on neoplastic transformation. The results demonstrated that baicalein significantly inhibited E2-induced cell growth, motility, and invasiveness, and suppressed E2-induced misshapen acini formation in 3D cultures. Furthermore, it inhibited the ability of E2-induced cells to form clones in agarose and tumors in NOD/SCID immunodeficient mice. Docking studies using Sybyl-X 1.2 software showed that baicalein could bind to both estrogen receptor-α (ERa) and G-protein coupled estrogen receptor 30 (GPR30), which are two critical E2-mediated pathways. Baicalein prevented the E2-induced ERa-mediated activation of nuclear transcriptional signaling by interfering with the trafficking of ERa into the nucleus and subsequent binding to estrogen response elements, thereby decreasing the mRNA levels of ERa target genes. It also inhibited E2-induced GPR30-mediated signal transduction, as well as the transcription of GPR30-regulated genes. Therefore, these results suggest that baicalein is a potential drug for reducing the risk of estrogen-dependent breast cancer.

Expression of ERβ gene in breast carcinoma and the relevance in neoadjuvant therapy

In the present study, we examined the expression of the estrogen receptor β (ERβ) gene in breast cancer and its relevance in neoadjuvant therapy. In total, 120 breast cancer patients who were hospitalized in the Departments of Breast Disease and Medical Oncology served as the subjects of this study. The subjects were diagnosed with breast cancer phase II to phase IIIA, as confirmed by aspiration biopsy and iconography. The patients were divided into two groups in a randomized control manner, with 60 patients in each group. The experimental group was administered the taxotere + epirubicin + cyclophosphamide (TEC) plan for 3–4 cycles of chemotherapy before the modified radical operation of breast cancer. In the control group, no TEC chemotherapy was carried out prior to operation. Instead, the breast lesion was removed directly by operation. After the operation, the IHC method was used to stain the ERβ protein in the lesion tissue. The patients were classified according to whether the basement membrane was broken through; 5 cases had non-infiltrative carcinoma and 115 cases had infiltrative carcinoma. According to the pathology of the lesion, 114 cases had breast ductal carcinoma, 2 cases had mucinous breast carcinoma (of which there were 2 cases combined with ductal carcinoma), and 4 cases had breast lobular carcinoma. The ERβ gene was found to be expressed in normal and breast cancer tissues. When ERβ gene expression was compared before and after the chemotherapy, its expression was significantly increased in breast cancer tissues, which shows a significant statistical difference (P<0.05). In the experimental group, the expression of ERβ gene in carcinoma tissue was significantly lower than that in the control group, and differences were statistically significant (P<0.05). Therefore, expression of the ERβ gene in breast carcinoma tissues was high. The application of adjuvant chemotherapy before the modified radical operation for breast carcinoma can significantly lower the level of ERβ expression. The expression levels of ERβ gene in the carcinoma tissue of the patients can be treated as the evaluation index for neoadjuvant chemotherapy. Regarding targeted therapy and corresponding drug development for breast carcinoma, ERβ can act as one of the specific drug targets.

Variants of estrogen receptor alpha and beta genes modify the severity of sporadic breast cancer

INTRODUCTION

Reproductive factors pose a risk for sporadic breast cancer (BC) development owing to the lifetime exposure to estrogen, a hormone responsible for cell proliferation in the breast. Because variants of the estrogen receptor (ER) alpha and beta genes have been associated with BC risk in numerous populations, the objective of the study was to determine whether the risk and severity of sporadic BC was associated with the rs2228480 (ESR1) and rs4986938 (ESR2) variants in a Brazilian population.

METHODS

A total of 253 DNA samples from sporadic BC patients and 257 DNA samples from healthy controls were studied. The samples were genotyped by PCR-RFLP. Epidemiological, clinical, and reproductive factors were analyzed. Statistical tests conducted included the χ² test, Fisher's exact test, and Mann-Whitney and Kruskal-Wallis tests or their parametric equivalents.

RESULTS

There was a high frequency of the rs2228480*GG genotype among the ER-positive tumors (OR=2.13; 95% CI=1.189-3.816) and it showed minor association with clinical stage 0 (OR=0.324; 95% CI=0.116-0.904). The rs2228480*GA genotype was associated with minor ER expression, whereas rs2228480*GG was associated with high expression of the progesterone receptor (PR). The frequency of rs4986938*GA was high among women who breastfed (OR=2.11; 95% CI=1.203-3.702), and it showed high association with clinical stage 0 (OR=4.383; 95% CI=1.606-11.96) whereas it had minor association with systemic arterial hypertension (OR=0.53; 95% CI=0.319-0.880). The rs2228480*GG/rs4986938*GG haplotype occurred at a low frequency among women who breastfed (OR=0.525; 95% CI=0.298-0.924) but it was associated with a high expression of PR.

CONCLUSION

The rs2228480 and rs4986938 variants did not alter sporadic BC risk, but they did modulate the BC severity.

How interacting pathways are regulated by miRNAs in breast cancer subtypes

BACKGROUND

An important challenge in cancer biology is to understand the complex aspects of the disease. It is increasingly evident that genes are not isolated from each other and the comprehension of how different genes are related to each other could explain biological mechanisms causing diseases. Biological pathways are important tools to reveal gene interaction and reduce the large number of genes to be studied by partitioning it into smaller paths. Furthermore, recent scientific evidence has proven that a combination of pathways, instead than a single element of the pathway or a single pathway, could be responsible for pathological changes in a cell.

RESULTS

In this paper we develop a new method that can reveal miRNAs able to regulate, in a coordinated way, networks of gene pathways. We applied the method to subtypes of breast cancer. The basic idea is the identification of pathways significantly enriched with differentially expressed genes among the different breast cancer subtypes and normal tissue. Looking at the pairs of pathways that were found to be functionally related, we created a network of dependent pathways and we focused on identifying miRNAs that could act as miRNA drivers in a coordinated regulation process.

CONCLUSIONS

Our approach enables miRNAs identification that could have an important role in the development of breast cancer.

A calixpyrrole derivative acts as an antagonist to GPER, a G-protein coupled receptor: mechanisms and models

Estrogens regulate numerous pathophysiological processes, mainly by binding to and activating estrogen receptor (ER)α and ERβ. Increasing amounts of evidence have recently demonstrated that G-protein coupled receptor 30 (GPR30; also known as GPER) is also involved in diverse biological responses to estrogens both in normal and cancer cells. The classical ER and GPER share several features, including the ability to bind to identical compounds; nevertheless, some ligands exhibit opposed activity through these receptors. It is worth noting that, owing to the availability of selective agonists and antagonists of GPER for research, certain differential roles elicited by GPER compared with ER have been identified. Here, we provide evidence on the molecular mechanisms through which a calixpyrrole derivative acts as a GPER antagonist in different model systems, such as breast tumor cells and cancer-associated fibroblasts (CAFs) obtained from breast cancer patients. Our data might open new perspectives toward the development of a further class of selective GPER ligands in order to better dissect the role exerted by this receptor in different pathophysiological conditions. Moreover, calixpyrrole derivatives could be considered in future anticancer strategies targeting GPER in cancer cells.

Transforming growth factor-β signaling pathway cross-talking with ERα signaling pathway on regulating the growth of uterine leiomyoma activated by phenolic environmental estrogens in vitro

The aim of this paper is to study the participation of transforming growth factor-β (TGF-β) signaling pathway in mediating the growth of human uterine leiomyoma (UL) activated by phenolic environmental estrogens (EEs), via the interaction between TGF-β and ER signaling pathways. The UL cells were prepared by primary culture and subculture methods. To validate the role of TGF-β3 (5 ng/ml) for the viability of human uterine leiomyoma cells, CCK-8 assay was performed in each of five treatment groups including E2 group (E2 10(9) mol/l), BPA group (bisphenol A 10 μmol/l), NP group (nonylphenol 32 μmol/l), OP group (octylphenol 8 μmol/l), or control group (DMSO only). Subsequently, qRT-PCR was applied to detect mRNA expressions of ERα and c-fos, while western blot assay was used to test the expressions of p-Smad3, SnoN, and c-fos proteins in all settings mentioned above; the expressions were compared among different groups, and also in settings with and without synchronous treatment of ICI 182,780. Primarily cultured UL cells were successfully established. Compared with the control group, there were statistically significant increases in the proliferation rate of the UL cells in all EE groups or treated with TGF-β3 only (p < 0.05). Nevertheless, a slight decrease in proliferation rate of UL was detected in coexistence with TGF-β3 in all EE groups (p > 0.05). Interestingly, mRNA expressions of ERα and c-fos reduced in the setting of coexistence of TGF-β3 and EEs compared to isolated EE treatment (p < 0.05). Compared with the control group, the expression of p-Smad3 and c-fos proteins significantly decreased (p < 0.05) in each of E2, BPA, NP, and OP group, and the expression of SnoN protein also significantly reduced only in BPA and NP groups (p < 0.05), followed by TGF-β3 treatment. When adding ICI 182,780, the expression of p-Smad3 protein significantly increased in OP group (p < 0.05), but slightly increased in E2, BPA, NP, and OP groups (p > 0.05). However, compared with the control group, the expressions of SnoN and c-fos proteins significantly decreased (p < 0.05) after adding ICI182,780. Moreover, there was a significant statistical difference in the expression of p-Smad3, SnoN, and c-fos proteins between pre- and post-treatment of ICI 182,780 in all groups (p < 0.05). The ERα signaling pathway and TGF-β signaling pathway have different roles in the control of UL cell proliferation. The phenolic EEs can be a promoter of UL cell proliferation, which is mediated by ERα signaling pathway and its cross-talking with TGF-β signaling pathway. Both less exposure to EEs and blockade of TGF signaling pathway are necessary strategies to prevent UL.

Krüppel-like factors are effectors of nuclear receptor signaling

Binding of steroid and thyroid hormones to their cognate nuclear receptors (NRs) impacts virtually every aspect of postembryonic development, physiology and behavior, and inappropriate signaling by NRs may contribute to disease. While NRs regulate genes by direct binding to hormone response elements in the genome, their actions may depend on the activity of other transcription factors (TFs) that may or may not bind DNA. The Krüppel-like family of transcription factors (KLF) is an evolutionarily conserved class of DNA-binding proteins that influence many aspects of development and physiology. Several members of this family have been shown to play diverse roles in NR signaling. For example, KLFs (1) act as accessory transcription factors for NR actions, (2) regulate expression of NR genes, and (3) as gene products of primary NR response genes function as key players in NR-dependent transcriptional networks. In mouse models, deletion of different KLFs leads to aberrant transcriptional and physiological responses to hormones, underscoring the importance of these proteins in the regulation of hormonal signaling. Understanding the functional relationships between NRs and KLFs will yield important insights into mechanisms of NR signaling. In this review we present a conceptual framework for understanding how KLFs participate in NR signaling, and we provide examples of how these proteins function to effect hormone action.

An interspecies conserved motif of the mouse immune system-released activating agent (ISRAA) induces proliferative effects on human cells

We have recently described an immune system-released activating agent (ISRAA) as a nervous system-induced factor that stimulates immune responses in the mouse spleen. However, the human ISRAA has not yet been identified. In this study, we examined the effects of the mouse ISRAA protein on human peripheral blood mononuclear cells (PBMCs), to observe if the biological activity of this molecule is consistent between the two different species. Mouse ISRAA demonstrated dose-dependent dualistic effects on human cells, as 5 µg exhibited positive apoptosis and 50 pg exhibited significant proliferation (P<0.05). Furthermore, immunosuppressed cells from patients undergoing immunosuppressive therapy demonstrated significant proliferation to 50 pg ISRAA (P<0.05). Studies to compare sequences in different species revealed a preserved motif, exhibiting 72% similarity with the interspecies conserved signal peptide motif of tumor necrosis factor receptor 1 (TNFR1). A mutant ISRAA lacking this motif was produced and tested for its biological effects. The mutant ISRAA demonstrated neither apoptotic nor proliferative effects compared with wild type. Therefore, an interspecies conserved domain of ISRAA constitutes the active site of the molecule, and its effects on immunocompromised cells should be investigated for future therapies in the treatment of immunosuppressive disorders.