Estrogen Receptor-positive Human Breast Research Articles

Neutrophil-to-lymphocyte ratio at the end of treatment with CDK4/6 inhibitors is an independent prognostic factor for ER-positive HER2-negative advanced breast cancer.

The aim of this study was to elucidate the clinical significance of peripheral blood biomarkers, including absolute lymphocyte count (ALC) and neutrophil-to-lymphocyte ratio (NLR), at the end of treatment (EOT) with CDK4/6 inhibitors abemaciclib and palbociclib in patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative advanced breast cancer. We included 67 patients treated with fulvestrant plus abemaciclib or palbociclib. Overall survival (OS) since the EOT with CDK/4/6 inhibitors was compared in relation to the levels of ALC and NLR. The cut-off values of ALC and NLR were set at 1000/μL and 3, respectively. Patients with a high ALC at EOT showed significantly longer OS than those with a low ALC (p = 0.0358). Moreover, patients with a low NLR at EOT showed significantly longer OS than those with a high NLR at EOT (p = 0.0044). Looking at the changes of ALC and NLR between baseline and the EOT, patients with a high ALC both at baseline and at the EOT showed significantly longer OS than others (p = 0.0201). Similarly, patients with a low NLR both at baseline and at the EOT showed significantly longer OS after EOT than others (p = 0.0136). Multivariable analysis revealed that the NLR at EOT (low vs. high) and changes in NLR (low at baseline to low at EOT vs. others) were significant and independent prognostic factors for OS after EOT (p = 0.0337, p = 0.0039, respectively). NLR at EOT with CDK4/6 inhibitors is a significant and independent prognostic marker for patients with ER-positive HER2-negative advanced breast cancer.

Combining In Vitro, In Vivo, and Network Pharmacology Assays to Identify Targets and Molecular Mechanisms of Spirulina-Derived Biomolecules against Breast Cancer.

The current research employed an animal model of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary gland carcinogenesis. The estrogen receptor-positive human breast adenocarcinoma cell line (MCF-7) was used for in vitro analysis. This was combined with a network pharmacology-based approach to assess the anticancer properties of Spirulina (SP) extract and understand its molecular mechanisms. The results showed that the administration of 1 g/kg of SP increased the antioxidant activity by raising levels of catalase (CAT) and superoxide dismutase (SOD), while decreasing the levels of malonaldehyde (MDA) and protein carbonyl. A histological examination revealed reduced tumor occurrence, decreased estrogen receptor expression, suppressed cell proliferation, and promoted apoptosis in SP protected animals. In addition, SP disrupted the G2/M phase of the MCF-7 cell cycle, inducing apoptosis and reactive oxygen species (ROS) accumulation. It also enhanced intrinsic apoptosis in MCF-7 cells by upregulating cytochrome c, Bax, caspase-8, caspase-9, and caspase-7 proteins, while downregulating Bcl-2 production. The main compounds identified in the LC-MS/MS study of SP were 7-hydroxycoumarin derivatives of cinnamic acid, hinokinin, valeric acid, and α-linolenic acid. These substances specifically targeted three important proteins: ERK1/2 MAPK, PI3K-protein kinase B (AKT), and the epidermal growth factor receptor (EGFR). Network analysis and molecular docking indicated a significant binding affinity between SP and these proteins. This was verified by Western blot analysis that revealed decreased protein levels of p-EGFR, p-ERK1/2, and p-AKT following SP administration. SP was finally reported to suppress MCF-7 cell growth and induce apoptosis by modulating the PI3K/AKT/EGFR and MAPK signaling pathways suggesting EGFR as a potential target of SP in breast cancer (BC) treatment.

Amino acid derivative of probenecid potentiates apoptosis-inducing effects of vinblastine by increasing oxidative stress in a cancer cell-specific manner

Many chemotherapeutic drugs suffer from multidrug resistance (MDR). Efflux transporters, namely ATP-binding cassettes (ABCs), that pump the drugs out of the cancer cells comprise one major reason behind MDR. Therefore, ABC inhibitors have been under development for ages, but unfortunately, without clinical success. In the present study, an l-type amino acid transporter 1 (LAT1)-utilizing derivative of probenecid (PRB) was developed as a cancer cell-targeted efflux inhibitor for P-glycoprotein (P-gp), breast cancer resistant protein (BCRP) and/or several multidrug resistant proteins (MRPs), and its ability to increase vinblastine (VBL) cellular accumulation and apoptosis-inducing effects were explored. The novel amino acid derivative of PRB (2) increased the VBL exposure in triple-negative human breast cancer cells (MDA-MB-231) and human glioma cells (U-87MG) by 10–68 -times and 2-5-times, respectively, but not in estrogen receptor-positive human breast cancer cells (MCF-7). However, the combination therapy had greater cytotoxic effects in MCF-7 compared to MDA-MB-231 cells due to the increased oxidative stress recorded in MCF-7 cells. The metabolomic study also revealed that compound 2, together with VBL, decreased the transport of those amino acids essential for the biosynthesis of endogenous anti-oxidant glutathione (GSH). Moreover, the metabolic differences between the outcomes of the studied breast cancer cell lines were explained by the distinct expression profiles of solute carriers (SLCs) that can be concomitantly inhibited. Therefore, attacking several SLCs simultaneously to change the nutrient environment of cancer cells can serve as an adjuvant therapy to other chemotherapeutics, offering an alternative to ABC inhibitors.

TCGA RNA-Seq and Tumor-Infiltrating Lymphocyte Imaging Data Reveal Cold Tumor Signatures of Invasive Ductal Carcinomas and Estrogen Receptor-Positive Human Breast Tumors.

Comparative studies of immune-active hot and immune-deserted cold tumors are critical for identifying therapeutic targets and strategies to improve immunotherapy outcomes in cancer patients. Tumors with high tumor-infiltrating lymphocytes (TILs) are likely to respond to immunotherapy. We used the human breast cancer RNA-seq data from the cancer genome atlas (TCGA) and classified them into hot and cold tumors based on their lymphocyte infiltration scores. We compared the immune profiles of hot and cold tumors, their corresponding normal tissue adjacent to the tumor (NAT), and normal breast tissues from healthy individuals from the Genotype-Tissue Expression (GTEx) database. Cold tumors showed a significantly lower effector T cells, lower levels of antigen presentation, higher pro-tumorigenic M2 macrophages, and higher expression of extracellular matrix (ECM) stiffness-associated genes. Hot/cold dichotomy was further tested using TIL maps and H&E whole-slide pathology images from the cancer imaging archive (TCIA). Analysis of both datasets revealed that infiltrating ductal carcinoma and estrogen receptor ER-positive tumors were significantly associated with cold features. However, only TIL map analysis indicated lobular carcinomas as cold tumors and triple-negative breast cancers (TNBC) as hot tumors. Thus, RNA-seq data may be clinically relevant to tumor immune signatures when the results are supported by pathological evidence.

Design of rapamycin and resveratrol coloaded liposomal formulation for breast cancer therapy.

Aims: The development of rapamycin (RAP) and resveratrol (RSV) coloaded liposomes (RAP-RSV-LIP) for breast cancer therapy. Materials & methods: Liposomes were prepared using a high-pressure homogenization technique and evaluated according to their physicochemical characteristics, cellular uptake and cytotoxicity against tumoral and normal cells. Results & conclusion: The RAP-RSV-LIP showed negative surface charge, size around 100nm, low polydispersity and high encapsulation efficiency for RAP and RSV (58.87 and 63.22%, respectively). RAP-RSV-LIP showed great stability over 60days and a prolonged drug-release profile. In vitro studies indicated that RAP-RSV-LIP were internalized in an estrogen receptor-positive human breast cancer cell line (MCF-7, 34.2%) and improved cytotoxicity when compared with free drugs. Therefore RAP-RSV-LIP showed great antitumoral potential against breast cancer cells.

Abstract P2-24-08: Altersolanol B, a fungal metabolite, induces proteasome-dependent degradation of estrogen receptor α (ERα) and inhibits downstream signaling targets in ER+ breast adenocarcinoma cells

Abstract We recently reported the cellular signal-modulating properties of altersolanol B (AB), a minor fungal tetrahydroanthraquinone (THAQ) metabolite, in the estrogen receptor positive (ER+) human breast adenocarcinoma cell lines, MCF-7 and T47D. MCF-7 (IC50 5.5 µM) and T47D (IC50 8.8 µM) were observed to be 4- and 2.4-fold more sensitive to the antiproliferative effects of AB, respectively, compared to MDA-MB-231 (triple-negative, IC50 21.3 µM). AB disrupted both AKT and ERK1/2 signaling leading to intrinsic apoptosis in MCF-7. The clinical limitations of multi-agent combination therapy that targets multiple pathways in cancer may potentially be circumvented by using a single molecule, such as AB, that inhibits both AKT and ERK1/2 signaling. The THAQ pharmacophore, with its disrupted conjugated ring system and relative redox inactivity, may possess greater mechanistic advantage against ER+ breast cancer when compared to the fully conjugated ring systems of the anthracyclines (doxorubicin) and anthraquinone (mitoxantrone) that are associated with nonselective mechanisms. The present phase of our study provides evidence that AB downregulated ERα expression at the post-translational level through the induction of proteasome-dependent degradation similar to a classical selective estrogen receptor degrader (SERD). AB dose-dependently downregulated both wild-type (WT)- and 17β-estradiol (E2)-stimulated ERα protein expression without altering mRNA expression in ER+ cells. This was corroborated by the marked reduction in the expression of downstream ERα target genes (cathepsin D and pS2). AB also dose-dependently downregulated cyclin D1, the estrogen-independent activator of ER. Antiproliferative effects were enhanced when ER+ cells were exposed to a combination of AB and the ERα-selective antagonist, MPP dihydrochloride. The AKT activator, SC79, showed that the AB-induced ERα protein downregulation was independent of the inhibition of AKT-FOXO1 signaling. The expression of Hsp90 was not affected. Co-treatment with the protein synthesis inhibitor, cycloheximide, revealed that AB downregulated ERα expression at the post-translational level. The proteosome inhibitor, MG-132, effectively suppressed AB-induced ERα degradation and restored cellular proliferation. In silico approaches were adopted to probe the direct binding of AB to ERα. AB demonstrated significant binding affinity with human ERα (PDB ID - 3ert) compared to the binding of the standard SERD, fulvestrant. Non-covalent bonding interaction analysis further revealed that, much like fulvestrant, AB successfully interacted with 5 major amino acid residues (i.e., Ala350, Asp351, Leu525, Leu536 and Trp383) at the ligand-binding domain of ERα which is stabilized by 7 non-bonding interactions. Principal component analysis indicated that binding with AB improved the compactness of 3ert folding. Molecular dynamics simulation indicated that the 3ert-AB interaction was stable even in the 100 ns simulated physiological environment. Citation Format: Md Afjalus Siraj, Md Sajjadur Rahman, Aaron T. Jacobs, Ghee T. Tan. Altersolanol B, a fungal metabolite, induces proteasome-dependent degradation of estrogen receptor α (ERα) and inhibits downstream signaling targets in ER+ breast adenocarcinoma cells [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-24-08.

Δ9-Tetrahydrocannabinol stimulation of estrogen receptor-positive MCF-7 breast cancer cell migration: Interfering interaction with the estrogenic milieu.

The effects of extended Δ9-tetrahydrocannabinol (Δ9-THC) exposure on estrogen receptor-positive human breast cancer MCF-7 cells have been investigated; however, the effects of Δ9-THC exposure for a shorter duration remain unclear. In this study, we sought to study whether Δ9-THC stimulates the migration of MCF-7 cells under both estrogenic and estrogen-deprived conditions over a short period (approximately 6h). MCF-7 cells were treated with Δ9-THC under estrogenic or estrogen-deprived conditions, and cell migration was subsequently analyzed. Δ9-THC-stimulated migration of MCF-7 cells 6h after exposure was only observed in the estrogen-deprived condition. However, Δ9-THC-mediated migration was counteracted under estrogenic conditions without affecting cell proliferation and estrogen receptor expression during this period. Δ9-THC can stimulate MCF-7 cell migration under estrogen-deprived conditions; however, there is an interfering interaction between Δ9-THC and the estrogenic milieu that influences the migration of MCF-7 cells.

Advantages and Disadvantages of Two <i>In Vitro</i> Assays in Evaluating Aromatase Activity: “A Cell-Based and a Cell-Free Assay”

Aromatase is an enzyme that catalyzes the conversion of androgens to estrogens. While inhibition of aromatase is a useful approach for treating breast cancer, it may also have toxicological consequences due to its endocrine disrupting/modulating effect. In this study, sensitivity and performance of two in vitro assays -a cell free and a cell-based- for evaluating aromatase activity were investigated by testing known aromatase inhibitors and partial validation of the methods was performed. Advantages and disadvantages of these methods are also discussed. Aromatase activity was evaluated via two in vitro models; direct measurement with a cell-free assay using a fluorescent substrate and recombinant human enzyme and indirect evaluation with a cell-based assay where cell proliferation was determined in estrogen receptor positive human breast cancer cells (MCF-7 BUS) in the absence of estrogen and the presence of testosterone. In the cell-free direct measurement assay, reference compounds ketoconazole and aminoglutethimide have been shown to inhibit the aromatase enzyme with half-maximal inhibitory concentration (IC50) values concordant with literature. In cell-based indirect measurement assay, only ketoconazole dose-dependently inhibited cell proliferation with 3.47 x 10-7 M IC50. Inter-assay and intra-assay reproducibility of both methods was found to be within acceptable deviation levels. Both methods can be successfully applied. However, to evaluate the potential aromatase activity of the novel compounds in vitro, it seems better to perform both the cell-based and the cell-free assays that allows low-moderate biotransformation and eliminate cytotoxicity potential, respectively.

Absolute Lymphocyte Count Is an Independent Prognostic Factor for ER-positive HER2-negative Advanced Breast Cancer Patients Treated With CDK4/6 Inhibitors.

The aim of this study was to elucidate the clinical significance of peripheral blood biomarkers, including absolute lymphocyte count (ALC), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and C-reactive protein (CRP) in patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative advanced breast cancer treated with the CDK4/6 inhibitors, abemaciclib and palbociclib. A total of 83 patients treated with fulvestrant plus abemaciclib or palbociclib were included in this study. Progression-free survival (PFS) and overall survival (OS) were compared in relation to baseline levels of ALC, NLR, PLR and CRP. The cut-off values of ALC, NLR, PLR, and CRP for PFS were determined from the receiver operating characteristic curve using the Youden index for area under the curve and set at 1,212/μl, 1.964, 170 and 0.220 mg/dl, respectively. In the abemaciclib-treated group, ALC-high patients showed significantly better PFS than ALC-low patients (p=0.0151) and multivariate analysis revealed that ALC was an independent prognostic factor for PFS (p=0.0085). In the palbociclib-treated group, there was no significant relationship between any peripheral blood biomarkers and PFS. In both treatment groups, ALC-high patients showed significantly better OS than ALC-low patients (p=0.0169 and 0.0290, respectively). Multivariate analysis revealed ALC was an independent prognostic factor for OS in both abemaciclib- and palbociclib-treated groups (p=0.0112 and 0.0202, respectively). ALC is an independent prognostic factor for estrogen receptor-positive human epidermal growth factor receptor 2-negative advanced breast cancer patients treated with the CDK4/6 inhibitors abemaciclib and palbociclib.

Tamoxifen-resistant breast cancer cells exhibit reactivity with Wisteria floribunda agglutinin.

Glycosylation is one of the most important post-translational modifications of cell surface proteins involved in the proliferation, metastasis and treatment resistance of cancer cells. However, little is known about the role of glycosylation as the mechanism of breast cancer cell resistance to endocrine therapy. Herein, we aimed to identify the glycan profiles of tamoxifen-resistant human breast cancer cells, and their potential as predictive biomarkers for endocrine therapy. We established tamoxifen-resistant cells from estrogen receptor-positive human breast cancer cell lines, and their membrane-associated proteins were subjected to lectin microarray analysis. To confirm differential lectin binding to cellular glycoproteins, we performed lectin blotting analyses after electrophoretic separation of the glycoproteins. Mass spectrometry of the tryptic peptides of the lectin-bound glycoproteins was further conducted to identify glycoproteins binding to the above lectins. Finally, expression of the glycans that were recognized by a lectin was investigated using clinical samples from patients who received tamoxifen treatment after curative surgery. Lectin microarray analysis revealed that the membrane fractions of tamoxifen-resistant breast cancer cells showed increased binding to Wisteria floribunda agglutinin (WFA) compared to tamoxifen-sensitive cells. Glycoproteins seemed to be responsible for the differential WFA binding and the results of mass spectrometry revealed several membrane glycoproteins, such as CD166 and integrin beta-1, as candidates contributing to increased WFA binding. In clinical samples, strong WFA staining was more frequently observed in patients who had developed distant metastasis during tamoxifen treatment compared with non-relapsed patients. Therefore, glycans recognized by WFA are potentially useful as predictive markers to identify the tamoxifen-resistant and relapse-prone subset of estrogen receptor-positive breast cancer patients.

Altersolanol B, a fungal tetrahydroanthraquinone, inhibits the proliferation of estrogen receptor-expressing (ER+) human breast adenocarcinoma by modulating PI3K/AKT, p38/ERK MAPK and associated signaling pathways

The present study focused on the apoptosis-inducing effects and cellular signal-modulating properties of altersolanol B (AB), a minor fungal tetrahydroanthraquinone (THAQ) metabolite, in the estrogen receptor positive (ER+) human breast adenocarcinoma cell line, MCF-7. AB demonstrated approximately 4-fold greater antiproliferative activity in ER+ MCF-7 cells (IC50 5.5 μM) compared to the ER-negative (triple-negative) MDA-MB-231 (IC50 21.3 μM). The viability of normal breast fibrocystic epithelial cells, MCF-10A, was unaffected. AB induced intrinsic apoptosis in MCF-7 cells; it triggered the activation of caspase 9 and poly (ADP-ribose) polymerase (PARP), upregulated the expression of pro-apoptotic Bax, and downregulated the expression of anti-apoptotic Bcl-2. AB induced cell cycle arrest at G0/G1, as indicated by the downregulation of key checkpoint proteins operating at the G0/G1 phase of the cell cycle (cyclin D1, CDK4 and CDK2). The observed increase in p21Waf1/Cip1 and p53 expression may facilitate cell cycle arrest, and the subsequent induction of apoptosis. AB lacked significant effects on intracellular ROS levels, while it down-regulated nuclear factor erythroid 2-related factor 2 (Nrf2), and the Nrf2-dependent antioxidant enzyme, heme oxygenase-1. The compound disrupted AKT signaling through the downregulation of phospho-AKT and phospho-FOXO1, and the upregulation of PTEN, a phosphatase and tumor suppressor that negatively regulates the PI3K/AKT pathway. AB also disrupted the phosphorylation of AKT-controlled eukaryotic translation initiation factor, 4E-BP1, and GSK-3β, both of which are aberrantly regulated in human cancer. The AB-dependent downregulation of NF-κB was corroborated by the inhibition of TNFα-induced NF-κB activity as monitored in a luciferase reporter. The NF-κB inhibitory activity of AB was 3-fold more potent than that of the standard inhibitor, N-p-Tosyl-l-phenylalanine chloromethyl ketone. In addition to reducing the pro-survival effects of NF-кB, the inhibition of AKT phosphorylation by AB may also lead to FOXO1-mediated growth arrest and apoptosis. AB upregulated the expression of phospho-MKK4 and phospho-p38, and downregulated the expression of phospho-MEK1/2 and phospho-ERK1/2 indicating opposing effects on the two important oncogenic signaling cascades that are aberrantly activated in many cancers. AB disrupted both the AKT and ERK1/2 signaling pathways leading to apoptosis in ER+ MCF-7 cells through mitochondria-associated mechanisms coupled with the potent inhibition of NF-кB activation. The clinical limitations of multi-agent combination therapy that targets multiple pathways in cancer may potentially be circumvented by using a single molecule, such as AB, that inhibits both AKT and ERK1/2 signaling. Our preliminary study suggested that the THAQ pharmacophore, with its disrupted conjugated ring system and relative redox inactivity, may possess greater mechanistic advantage against ER+ breast cancer when compared to the fully conjugated ring systems of the anthraquinone that possess intrinsic redox activity and DNA interacting ability. This study supports the continued investigation of THAQs as lead molecules in anticancer drug discovery and development.

Structural Characterization, DFT, Molecular Docking and Cytotoxic Studies of Metal (II) Complexes Derived from Thiosemicarbazide

Co(II), Ni(II) and Cu(II) complexes of N and O donor ligand derived from ,5-dinitrosalicylicacid and thiosemicarbazide, the spectroscopy techniques like UV-Visible, FT-IR, NMR, mass spectrometry, p-XRD and SEM analysis were used to structurally characterize the metal complexes. From the analytical and spectral evidence, the square planar and octahedral geometry has been proposed to metal (II) complexes. In addition to this computational density functional theory (DFT) using B3LYP/6-31Gþ(d, p)/Lanl2dz(f) method in the ground state was performed, the calculations were done to confirm the geometry of the complexes and also HOMO-LUMO excitation energies levels were also calculated. Additionally, MTT test was used to perform cytotoxic assays on selected MCF-7 (estrogen receptor-positive human breast cancer cells) and HeLa (human cervical cancer cell line) cell lines. The antibacterial test was performed via the disc plate method against Escherichia coli and Staphylococcus aureus, and was further supported by molecular docking interactions using protein receptor SEC2 (PDB code: 1STE) in Staphylococcus aureus.

Preliminary screening of antioxidant and cytotoxic potential of green seaweed, Halimeda opuntia (Linnaeus) Lamouroux

Marine natural products have displayed numerous advantageous effects on biological activities, including antioxidants and cytotoxicity. The total lipids, carotenoids, chlorophyll a and b content, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of methanolic crude extract of the green seaweed Halimeda opuntia were all measured in this study. The TPC of the extracts was determined according to the Folin-Ciocalteu method, yielding a result of 55.04 ± 0.98 mg GAE/g of extract. As determined by the aluminium chloride colorimetric method, the TFC of the extract was 40.02 ± 0.02 mg QE/g of extract. Antioxidant activity was determined by using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with different concentrations that ranged between 200 and 1000 µg/mL, noted H. opuntia as the highest in DPPH reduction (63.61 %) at 1000 µg/mL concentration. Total antioxidant capacity (TAC) of the extract was 57.36 ± 0.004 mg AAE/g extract at concentration of 1.0 mg/mL. The cytotoxic activity of this seaweed was pre-screened against a panel of cell lines including estrogen receptor-positive human breast adenocarcinoma (MCF-7), estrogen negative human breast adenocarcinoma (MDA-MB-231), human colorectal adenocarcinoma (HT-29), human hepatocellular carcinoma (HepG2), and mouse embryonic fibroblast (3T3) using the MTT assay. The content of total lipids in H. opuntia was 1.60 ± 0.002 %. Total carotenoids were 115.57 ± 0.98 µg/g, while chlorophyll a and b were 148.73 ± 2.60 µg/g and 290.83 ± 9.46 µg/g, respectively. In terms of cytotoxicity activity, methanolic extract of H. opuntia was found to be highly cytotoxic to MCF-7 cells, with an IC50 of 25.14 ± 1.02 g/mL, and slightly less so to 3T3 cells (IC50 65.23 ± 0.25 µg/mL). This study's findings suggest that natural pigments (carotenoids and chlorophyll), phytochemicals like phenolic and flavonoid compounds found in this species may play an important role and could be used as a natural cancer treatment.

The aromatase inhibitor letrozole restores FADS2 function in ER+ MCF7 human breast cancer cells

PurposePlasticity in fatty acid metabolism is increasingly recognized as a major feature influencing cancer progression and efficacy of treatments. Estrogen receptor positive MCF7 human breast cancer cells have long been known to have no FADS2-mediated Δ6-desaturase activity. Our objective was to examine the effect of estrogen and the “antiestrogen” aromatase inhibitor letrozole, on Δ5- and Δ6-desaturase synthesized fatty acids in vitro. MethodsEicosa-11,14-dienoic acid (20:2n-6), a known substrate for both FADS1 and FADS2, was used as a sentinel of relative FADS2 and FADS1 activity. MCF7 cells and four additional estrogen responsive wild type cell lines (HepG2, SK-N-SH, Y79 and Caco2) were studied. FAME were quantified by GC-FID and structures identified by GCCACI-MS/MS. ResultsIn all five cell lines, estrogen caused a dose dependent decrease in sciadonic acid (5,11,14–20:3, ScA) via apparent inhibition of FADS1 activity, and had no effect on FADS2 catalyzed synthesis of dihomo-gamma linolenic acid (8,11,14–20:3; DGLA). In MCF7 cells, letrozole caused a dose dependent increase in FADS2-catalyzed DGLA synthesis, which plateaued in SK-N-SH cells. ConclusionLetrozole restores Δ6-desaturase mediated synthesis of the anti-inflammatory PGE1-precursor DGLA in vitro and is the first endocrine-active agent to have opposing effects on FADS1 and FADS2 catalyzed activities.

Antiproliferative activity of five garcinia species collected in Sabah, Malaysian Borneo against estrogen receptor-human breast carcinoma (MCF-7) cell line

Garcinia species are well-known for their unique properties of having natural secondary metabolite compounds called xanthone as well as their ethnomedicinal values such as antioxidant, anticancer, anti-inflammatory and antibacterial properties. The study was conducted to investigate the antiproliferative activity of peel, flesh and seed extracts of G. dulcis, G. parvifolia, G. nitida, G. mangostana var. mangosta and G. cambogia collected from Malaysian Borneo (Sabah) against estrogen receptor-positive human breast carcinoma (MCF-7) cells. The antiproliferative activity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that G. dulcis seed induced strongest antiproliferative activity against MCF-7 cancer cell line with the IC50 value of 2.5 ± 0.0 µg/ml, followed by G. dulcis flesh, G. mangostana var. mangostana peel and G. dulcis peel with IC50 values of 9.33 ± 3.21, 11.17 ± 1.04 and 17.67 ± 2.08 µg/ml, respectively. Meanwhile, the IC50 value for G. cambogia peel was 56.67 ± 10.5 µg/ml. No IC50 value was detected in all parts of G. parvifolia and G. nitida at concentration tested ( < 100 µg/ml). Overall, this study clearly showed that the whole fruit of G. dulcis displayed potent cytotoxic effect by inducing antiproliferative activity at low concentration. Further studies are needed in the future to develop this fruit as pharmaceutical and nutraceutical product for the treatment and prevention against cancer.

The significance of Runx2 mediating alcohol-induced Brf1 expression and RNA Pol III gene transcription

Runx2 (Runt-related transcription factor 2) is a key transcription factor which is associated with osteoblast differentiation and expressed in ER+ (estrogen receptor positive) human breast cancer cell lines. Runx2 also participates in mammary gland development. Deregulation of RNA Pol III genes (polymerase III-dependent genes) is tightly linked to tumor development, while Brf1 (TFIIB-related factor 1) specifically regulates these gene transcription. However, nothing is known about the effect of Runx2 on Brf1 expression and Pol III gene transcription. Expression of Runx2, Brf1 and Pol III genes from the samples of human breast cancer and cell culture model were determined by the assays of RT-qPCR, immunoblot, luciferase reporter activity, immunohistochemistry, chromatin immunoprecipitation and Immunofluorescence. High expression of Runx2 is observed in the cases of breast cancer. The patients of high Runx2 expression at early stages display longer survival period, whereas the cases of high Runx2 at advanced stages reveal faster recurrence. The identification of signaling pathway indicates that JNK1 and c-Jun mediate Runx2 transcription. Repression of Runx2 reduces Brf1 expression and Pol III gene transcription. Further analysis indicates that Runx2 is colocalized with Brf1 in nucleus of breast cancer tissue. Both Runx2 and Brf1 synergistically modulate Pol III gene transcription. These studies indicate that Brf1 overexpression is able to be used as an early diagnosis biomarker of breast cancer, while high Runx2 expression indicates long survival period and faster recurrence. Runx2 mediates the deregulation of Brf1 and Pol III genes and its abnormal expression predicts the worse prognosis of breast cancer.

Interaction Between MUC1 and STAT1 Drives IFITM1 Overexpression in Aromatase Inhibitor-Resistant Breast Cancer Cells and Mediates Estrogen-Induced Apoptosis.

The human oncoprotein, mucin 1 (MUC1), drives tumorigenesis in breast carcinomas by promoting epithelial-to-mesenchymal transition (EMT), epigenetic reprogramming, and evasion of immune response. MUC1 interacts with STAT1, through JAK/STAT signaling, and stimulates transcription of IFN-stimulated genes, specifically IFN-induced transmembrane protein 1 (IFITM1). Our laboratory has previously shown that IFITM1 overexpression in aromatase inhibitor (AI)-resistant breast cancer cells promotes aggressiveness. Here, we demonstrate that differential regulation of MUC1 in AI-sensitive (MCF-7 and T-47D) compared with AI-resistant (MCF-7:5C) cells is critical in mediating IFITM1 expression. A tumor microarray of 94 estrogen receptor-positive human breast tumors correlated coexpression of MUC1 and IFITM1 with poor recurrence-free survival, poor overall survival, and AI-resistance. In this study, we investigated the effects of MUC1/IFITM1 on cell survival and proliferation. We knocked down MUC1 levels with siRNA and pharmacologic inhibitors, which abrogated IFITM1 mRNA and protein expression and induced cell death in AI-resistant cells. In vivo, estrogen and ruxolitinib significantly reduced tumor size and decreased expression of MUC1, P-STAT1, and IFITM1. IMPLICATIONS: MUC1 and IFITM1 overexpression drives AI resistance and can be targeted with currently available therapies.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/5/1180/F1.large.jpg.

4-(4-Bromophenyl)-thiazol-2-amine derivatives: synthesis, biological activity and molecular docking study with ADME profile

In order to overcome the challenges of microbial resistance as well as to improve the effectiveness and selectivity of chemotherapeutic agents against cancer, a novel series of 4-(4-bromophenyl)-thiazol-2-amine derivatives was synthesized and its molecular structures were confirmed by physicochemical and spectral characteristics. The synthesized compounds were further evaluated for their in vitro antimicrobial activity using turbidimetric method and anticancer activity against oestrogen receptor positive human breast adenocarcinoma cancer cell line (MCF7) by Sulforhodamine B (SRB) assay. The antimicrobial activity results revealed that compound p2, p3, p4 and p6 exhibited promising antimicrobial activity that are comparable to standard norfloxacin (antibacterial) and fluconazole (antifungal). Anticancer screening results demonstrated that compound p2 was found to be the most active one against cancer cell line when compared to the rest of the compounds and comparable to the standard drug (5-fluorouracil). The molecular docking study demonstrated that compounds, p2, p3, p4 and p6 displayed good docking score within binding pocket of the selected PDB ID (1JIJ, 4WMZ and 3ERT) and showed promising ADME properties.

Propagation of functional estrogen receptor positive normal human breast cells in 3D cultures.

Understanding how differentiation, microenvironment, and hormonal milieu influence human breast cell susceptibility to malignant transformation will require the use of physiologically relevant in vitro systems. We sought to develop a 3D culture model that enables the propagation of normal estrogen receptor alpha (ER) + cells. We tested soluble factors and protocols for the ability to maintain progenitor and ER + cells in cultures established from primary cells. Optimized conditions were then used to profile estrogen-induced gene expression changes in cultures from three pathology-free individuals. Long-term representation of ER + cells was optimal in medium that included three different TGFβ/activin receptor-like kinase inhibitors. We found that omitting the BMP signaling antagonist, Noggin, enhanced the responsiveness of the PGR gene to estradiol exposure without altering the proportions of ER + cells in the cultures. Profiling of estradiol-exposed cultures showed that while all the cultures showed immediate and robust induction of PGR, LRP2, and IGFB4, other responses varied qualitatively and quantitatively across specimens. We successfully identified conditions for the maintenance and propagation of functional ER + cells from normal human breast tissues. We propose that these 3D cultures will overcome limitations of conventional 2D cultures of partially or fully transformed cell lines by sustaining normal endocrine function and growth regulation of the cell populations that comprise intact breasts.

Modulation of the solubility properties of arene ruthenium complexes bearing stannyl ligands as potential anti-cancer agents

Cleavage of the known ruthenium dimer [RuCl2(η6-C6H5OCH2CH2OH)]2 (1), bearing a hydrophilic substituent on the η6 coordinated aromatic ring, with the phosphine ligands: triphenyl phosphine, triphenyl phosphite, trimethyl phosphite, and 1,3,5-triaza-7-phosphaadamantane (PTA) afforded the known complexes [RuCl2(η6-C6H5OCH2CH2OH)(PPh3)] (2a), [RuCl2(η6-C6H5OCH2CH2OH){P(OPh)3}] (2b), [RuCl2(η6-C6H5OCH2CH2OH){P(OMe3)}] (2c), and [RuCl2 (η6-C6H5OCH2CH2OH)(PTA)] (4). The reaction of the known complex 2a with SnCl2 afforded, by facile insertion of the SnCl2 moiety into the RuCl bond, the novel complex [RuCl(η6-C6H5OCH2CH2OH)(PPh3)(SnCl3)] (3a). Similarly, the reaction of complex 2b with SnCl2 afforded the novel complex [RuCl(η6-C6H5OCH2CH2OH){P(OPh)3}(SnCl3)] (3b). Complexes 3a and 3b were fully characterized by spectroscopy (Infrared (IR) -spectroscopy, 1H, 31P and 119Sn Nuclear Magnetic Resonance (NMR) spectroscopy, UV–Vis spectroscopy and high resolution ESI-MS) and their thermal behaviour elucidated by Thermogravimetric Analysis (TGA). Density Functional Theory (DFT) calculations (Level of theory B3LYP, basis set for H, C, P, O, N and Cl is 6-31 + G (d,p) and for Ru and Sn is DGDZVP) for complex 3a, 3b and 4 were also carried out, in particular to elucidate the bonding situation between Ru and Sn in complexes. The hitherto unprecedented anti-cancer activity of the complexes 2a – 2c as well as the novel stannyl complexes 3a and 3b were evaluated against MCF-7 (oestrogen receptor positive) human breast adenocarcinoma cell lines. All complexes show activity active against MCF-7 cell lines, indicating potential application as an anti-tumor agent.