Hormone-dependent Breast Cancer Cells Research Articles

Synthesis and anticancer properties of a hybrid molecule with the testosterone and estradiol head-groups

This is the first report on a unique hybrid molecule made of estradiol and testosterone (TS). This distinctive hybrid molecule (1) was designed to interact with both the estrogen receptor (ER) and the androgen receptor (AR) found in hormone-dependent female and male cancer cells, and was synthesized using ethynylestradiol (17EE) as the estrogenic component and 7α-(4-azido-but-2-enyl)-4-androsten-17β-ol-3-one as the androgenic counterpart in a seven-step reaction with ∼ 26 % overall yield. We reasoned that the dual receptor binding ability could allow 1 to act as an antihormone. This was tested on hormone-dependent and hormone-independent breast cancer (BCa) and prostate cancer (PCa) cells. The antiproliferative activity was also assessed on colon and skin cancer cells. We found that 1 was active against MCF7 (ER + ) BCa cells (IC50 of 4.9 μM), had lower inhibitory potency on LNCaP (AR + ) PCa cells (IC50 > 5 μM) and no effect on PC3 and DU145 (AR-) PCa cells. This suggests that the estrogenic component of 1 can interact with the ER on MCF7 cells more effectively than the androgenic component with the AR on LNCaP PCa cells, possibly due to a suboptimal spacer or linkage site(s). Nonetheless, the hybrid 1 was active against colon (HT-29) and melanoma (M21) cancer cells (IC50 of 3.5 μM and 2.3 μM, respectively), and had low cross-reactivity with the drug- and androgen-metabolizing cytochrome P450 3A4 (CYP3A4, IC50 ≫ 5 µM). These findings demonstrate the anticancer potential of 1 and warrant further explorations on this new type of hybrids.

Breast Cancer Prevention by Dietary Polyphenols: Microemulsion Formulation and In Vitro Studies

Concerns surrounding breast cancer have been increasing, as it leads to the current global cancer incidence and causes a high mortality rate in women. This study investigated the physiological effects of common dietary polyphenols that might prevent breast cancer progression. Quercetin, kaempferol, and rosmarinic acid were selected to explore their potential bioactivities. Each polyphenol was formulated into a microemulsion to improve its bioactivity and bioavailability. In vitro antioxidant and cytotoxicity activities of the selected polyphenols and their microemulsion forms were further investigated. The optimized microemulsion carrier with 1% oleic acid, 3% ethanol, 10% polysorbate 20, and 86% ultrapure water achieved more than 90% polyphenol encapsulation efficiency. The microemulsion was stable for more than 30 days when encapsulating polyphenol in the fluctuating temperature treatment. In vitro studies suggested that rosmarinic acid-loaded microemulsion had the best antioxidant activity compared with other polyphenol-loaded microemulsions (PL-MEs). Blank microemulsion and all PL-MEs significantly inhibited the proliferation of both hormone-dependent (T47D) and hormone-independent (MDA-MB-231) breast cancer cells. More studies are warranted to confirm the contribution of the microemulsion carrier components to the polyphenols’ improved antioxidant activity and high toxicity of PL-MEs on breast cancer cells.

Tuning of the Anti-Breast Cancer Activity of Betulinic Acid via Its Conversion to Ionic Liquids.

Betulinic acid (BA) is a natural pentacyclic triterpene with diverse biological activities. However, its low water solubility limits its pharmaceutical application. The conversion of pharmaceutically active molecules into ionic liquids (ILs) is a promising strategy to improve their physicochemical properties, stability, and/or potency. Here, we report the synthesis and characterization of 15 novel ILs containing a cation ethyl ester of a polar, non-polar, or charged amino acid [AAOEt] and an anion BA. Except for [ValOEt][BA], we observed preserved or up to 2-fold enhanced cytotoxicity toward hormone-dependent breast cancer cells MCF-7. The estimated IC50 (72 h) values within the series varied between 4.8 and 25.7 µM. We found that the most cytotoxic IL, [LysOEt][BA]2, reduced clonogenic efficiency to 20% compared to that of BA. In addition, we evaluated the effect of a 72 h treatment with BA or [LysOEt][BA]2, the most cytotoxic compound, on the thermodynamic behavior of MCF-7 cells. Based on our data, we suggest that the charged amino acid lysine included in the novel ILs provokes cytotoxicity by a mechanism involving alteration in membrane lipid organization, which could be accompanied by modulation of the visco-elastic properties of the cytoplasm.

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

Estrogen receptor alpha (ERα) is an important target for the discovery of new therapeutic drugs against hormone-dependent breast cancer. A series of phosphoryl-substituted steroidal pyridazines (Pho-STPYRs) were synthesized and biologically...

Evaluation of the Antiproliferative Properties of CpRu Complexes Containing N-Methylated Triazaphosphaadamantane Derivatives.

Piano-stool-{CpRu} complexes containing 1,3,5-triaza-7-phosphaadamantane (PTA), N-methyl-1,3,5-triaza-7-phosphaadamantane (mPTA), and 3,7-dimethyl-1,3,7-triaza-5-phosphabyciclo[3.3.1]nonane (dmoPTA) were evaluated as drugs against breast cancer. The evaluated compounds include two new examples of this family, the complexes [RuCp(DMSO-κS)(HdmoPTA)(PPh3)](CF3SO3)2 (8) and [RuCp(PPh3)2-µ-dmoPTA-1κP-2κ2N,N'-PdCl2](CF3SO3) (11), which have been synthesized and characterized by NMR, IR, and single-crystal X-ray diffraction. The cytotoxic activity of compounds was evaluated against MDA-MB-231 breast cancer cells, and the three most active complexes were further tested against the hormone-dependent MCF-7 breast cancer cell line. Their cell death mechanism and ruthenium uptake were also evaluated, as well as their binding ability to human serum albumin.

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

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

High glucose reduces anti-tumor activity of aromatase inhibitors in a hormone-dependent breast cancer cell model

One third of breast cancer patients also suffer from diabetes, which is associated with a 40% higher risk of mortality. Patients undergoing anti-cancer treatment are also exposed to xenoestrogens present in everyday life, which may affect the effectiveness of the therapies used. The purpose of our study was to analyzed the effect of metalloestrogens (Al, Cr[III]) on the effectiveness of aromatase inhibitors (AIs) under high glucose conditions prevailing in the cellular model. On two human breast cancer cell lines—MCF-7 and MCF-7/DOX—a cell viability assay, a flow cytometer analysis of apoptosis, and protein activity of BAX, Bcl-2, and VEGF-A by ELISA were carried out. Results were analyzed using one-way ANOVA, followed post hoc by Tukey’s multiple comparisons tests. High glucose conditions reduced the effectiveness of AIs in both cell lines (decreased cytotoxicity, inhibition of apoptosis, increase in Bcl-2/BAX ratio and angiogenesis), regardless of the combination with metalloestrogens. Hyperglycemia may affect the effectiveness of AIs to a greater extent than metalloestrogens alone - the activity of drugs in the presence of high glucose concentrations was significantly lower, regardless of the combination with metalloestrogens, which indicates the key role of hyperglycemia in attenuating their activity. Therefore controlling hyperglycemia and individualized treatment regimens in cancer patients with diabetes may have important therapeutic implications.

Resveratrol-Loaded Polymeric Nanoparticles: The Effects of D-α-Tocopheryl Polyethylene Glycol 1000 Succinate (TPGS) on Physicochemical and Biological Properties against Breast Cancer In Vitro and In Vivo.

Resveratrol (RSV), a phytoalexin from grapes and peanuts, has been reported to exhibit antiproliferative effects on various cancer cell lines. In breast cancer, RSV has been demonstrated to exert an antiproliferative effect on both hormone-dependent and hormone-independent breast cancer cell lines. However, RSV is a lipophilic drug, and its therapeutic effect could be improved through nanoencapsulation. Functionalizing polymeric nanoparticles based on polycaprolactone (PCL) with polyethylene glycol 1000 tocopheryl succinate (TPGS) has been reported to prolong drug circulation and reduce drug resistance. However, the effect of TPGS on the physicochemical properties and biological effects of breast cancer cells remains unclear. Therefore, this study aimed to develop RSV-loaded PCL nanoparticles using nanoprecipitation and investigate the effect of TPGS on the nanoparticles' physicochemical characteristics (particle size, zeta potential, encapsulation efficiency, morphology, and release rate) and biological effects on the 4T1 breast cancer cell line (cytotoxicity and cell uptake), in vitro and in vivo. The optimized nanoparticles without TPGS had a size of 138.1 ± 1.8 nm, a polydispersity index (PDI) of 0.182 ± 0.01, a zeta potential of -2.42 ± 0.56 mV, and an encapsulation efficiency of 98.2 ± 0.87%, while nanoparticles with TPGS had a size of 127.5 ± 3.11 nm, PDI of 0.186 ± 0.01, zeta potential of -2.91 ± 0.90 mV, and an encapsulation efficiency of 98.40 ± 0.004%. Scanning electron microscopy revealed spherical nanoparticles with low aggregation tendency. Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) identified the constituents of the nanoparticles and the presence of drug encapsulation in an amorphous state. In vitro release studies showed that both formulations followed the same dissolution profiles, with no statistical differences. In cytotoxicity tests, IC50 values of 0.12 µM, 0.73 µM, and 4.06 µM were found for the formulation without TPGS, with TPGS, and pure drug, respectively, indicating the potentiation of the cytotoxic effect of resveratrol when encapsulated. Flow cytometry and confocal microscopy tests indicated excellent cellular uptake dependent on the concentration of nanoparticles, with a significant difference between the two formulations, suggesting that TPGS may pose a problem in the endocytosis of nanoparticles. The in vivo study evaluating the antitumor activity of the nanoparticles confirmed the data obtained in the in vitro tests, demonstrating that the nanoparticle without TPGS significantly reduced tumor volume, tumor mass, maintained body weight, and improved survival in mice. Moreover, the biochemical evaluation evidenced possible hepatotoxicity for formulation with TPGS.

Synthesis, Biological Activity, ADME and Molecular Docking Studies of Novel Ursolic Acid Derivatives as Potent Anticancer Agents.

A series of new ursolic acid (UA) derivatives substituted with various amino acids (AAs) or dipeptides (DP) at the C-3 position of the steroid skeleton was designed and synthesized. The compounds were obtained by the esterification of UA with the corresponding AAs. The cytotoxic activity of the synthesized conjugates was determined using the hormone-dependent breast cancer cell line MCF-7 and the triple-negative breast cancer cell line MDA. Three derivatives (l-seryloxy-, l-prolyloxy- and l-alanyl-l-isoleucyloxy-) showed micromolar IC50 values and reduced the concentrations of matrix metalloproteinases 2 and 9. Further studies revealed that for two compounds (l-seryloxy- and l-alanyl-l-isoleucyloxy-), a possible mechanism of their antiproliferative action is the activation of caspase-7 and the proapoptotic Bax protein in the apoptotic pathway. The third compound (l-prolyloxy- derivative) showed a different mechanism of action as it induced autophagy as measured by an increase in the concentrations of three autophagy markers: LC3A, LC3B, and beclin-1. This derivative also showed statistically significant inhibition of the proinflammatory cytokines TNF-α and IL-6. Finally, for all synthesized compounds, we computationally predicted their ADME properties as well as performed molecular docking to the estrogen receptor to assess their potential for further development as anticancer agents.

Synthesis and Characterization of Folic Acid-Functionalized DPLA-co-PEG Nanomicelles for the Targeted Delivery of Letrozole.

An effective treatment for hormone-dependent breast cancer is chemotherapy using cytotoxic agents such as letrozole (LTZ). However, most anticancer drugs, including LTZ, are classified as class IV biopharmaceuticals, which are associated with low water solubility, poor bioavailability, and significant toxicity. As a result, developing a targeted delivery system for LTZ is critical for overcoming these challenges and limitations. Here, biodegradable LTZ-loaded nanocarriers were synthesized by solvent emulsification evaporation using nanomicelles prepared with dodecanol-polylactic acid-co-polyethylene glycol (DPLA-co-PEG). Furthermore, cancer cell-targeting folic acid (FA) was conjugated into the nanomicelles to achieve a more effective and safer cancer treatment. During our investigation, DPLA-co-PEG and DPLA-co-PEG-FA displayed a uniform and spherical morphology. The average diameters of DPLA-co-PEG and DPLA-co-PEG-FA nanomicelles were 86.5 and 241.3 nm, respectively. Our preliminary data suggest that both nanoformulations were cytocompatible, with ≥90% cell viability across all concentrations tested. In addition, the amphiphilic nature of the nanomicelles led to high drug loading and dispersion in water, resulting in the extended release of LTZ for up to 50 h. According to the Higuchi model, nanomicelles functionalized with FA have a greater potential for the controlled delivery of LTZ into target cells. This model was confirmed experimentally, as LTZ-containing DPLA-co-PEG-FA was significantly and specifically more cytotoxic (up to 90% cell death) toward MCF-7 cells, a hormone-dependent human breast cancer cell line, when compared to free LTZ and LTZ-containing DPLA-co-PEG. Furthermore, a half-maximal inhibitory concentration (IC50) of 87 ± 1 nM was achieved when MCF-7 cells were exposed to LTZ-containing DPLA-co-PEG-FA, whereas higher doses of 125 ± 2 and 100 ± 2 nM were required for free LTZ and LTZ-containing DPLA-co-PEG, respectively. Collectively, DPLA-co-PEG-FA represents a promising nanosized drug delivery system to target controllably the delivery of drugs such as chemotherapeutics.

Novel Therapeutic Combination Targets the Growth of Letrozole-Resistant Breast Cancer through Decreased Cyclin B1

As breast cancer cells transition from letrozole-sensitive to letrozole-resistant, they over-express epidermal growth factor receptor (EGFR), mitogen-activated protein kinase (MAPK), and human epidermal growth factor receptor 2 (HER2) while acquiring enhanced motility and epithelial-to-mesenchymal transition (EMT)-like characteristics that are attenuated and reversed by glyceollin treatment, respectively. Interestingly, glyceollin inhibits the proliferation and tumor progression of triple-negative breast cancer (TNBC) and estrogen-independent breast cancer cells; however, it is unlikely that a single phytochemical would effectively target aromatase-inhibitor (AI)-resistant metastatic breast cancer in the clinical setting. Since our previous report indicated that the combination of lapatinib and glyceollin induced apoptosis in hormone-dependent AI-resistant breast cancer cells, we hypothesized that combination therapy would also be beneficial for hormone independent letrozole-resistant breast cancer cells (LTLT-Ca) compared to AI-sensitive breast cancer cells (AC-1) by decreasing the expression of proteins associated with proliferation and cell cycle progression. While glyceollin + lapatinib treatment caused comparable inhibitory effects on the proliferation and migration in both cell lines, combination treatment selectively induced S and G2/M phase cell cycle arrest of the LTLT-Ca cells, which was mediated by decreased cyclin B1. This phenomenon may represent a unique opportunity to design novel combinatorial therapeutic approaches to target hormone-refractory breast tumors.

Synthesis and the In Vitro Evaluation of Antitumor Activity of Novel Thiobenzanilides.

Cancer is a generic term for a large group of diseases that are the second-leading cause of death worldwide, accounting for nearly 10 million deaths in 2020. Melanoma is a highly aggressive skin tumor with an increasing incidence and poor prognosis in the metastatic stage. Breast cancer still stands as one of the major cancer-associated deaths among women, and diagnosed cases are increasing year after year worldwide. Despite the recent therapeutic advances for this type of cancer, novel drugs and treatment strategies are still urgently needed. In this paper, the synthesis of 18 thiobenzanilide derivatives (17 of them new) is described, and their cytotoxic potential against melanoma cells (A375) and hormone-dependent breast cancer (MCF-7) cells is evaluated using the MTT assay. In the A375 cell line, most of the tested thiobenzanilides derivatives showed EC50 values in the order of μM. Compound 17 was the most promising, with an EC50 (24 h) of 11.8 μM. Compounds 8 and 9 are also interesting compounds that deserve to be further improved. The MCF-7 cell line, on the other hand, was seen to be less susceptible to these thiobenzanilides indicating that these compounds show different selectivity towards skin and breast cancer cells. Compound 15 showed the highest cytotoxic potential for MCF-7 cells, with an EC50 (24 h) of 43 μM, a value within the range of the EC50 value determined for tamoxifen (30.0 μM). ADME predictions confirm the potential of the best compounds. Overall, this work discloses a new set of thiobenzanilides that are worth being considered as new scaffolds for the further development of anticancer agents.

Novel synthetic derivatives of cinnamic and p-coumaric acids with antiproliferative effect on breast MCF-7 tumor cells

p-Coumaric acid is derived from cinnamic acid and is one of the major compounds in the Brazilian green propolis extract. Studies have shown that both p-coumaric acid and cinnamic acid have promising antiproliferative effects. In this context, aiming to increase the complexity of these active natural products and their activities, we performed coupling reactions with propargylamine and benzylamine, as well as with threonine, phenylalanine and lysine amino acids, aiming to enhance their antiproliferative effects towards the hormone-dependent breast cancer MCF-7 cells. Overall, the p-coumaric acid coupling with L-threonine amino acid (compound 15) had the best selectivity index (SI = 5.1), with half-maximal inhibitory concentration of 39.6 ± 1 μM, showing a high selectivity against hormone-dependent breast cancer cell lines MCF-7 and low cytotoxicity against the normal breast cell lines MCF-10A. Thus, this new natural product derivative may represent a prototype for the future development of antiproliferative agents, especially against hormone-dependent breast cancer.

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

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

The Effect of Metalloestrogens on the Effectiveness of Aromatase Inhibitors in a Hormone-Dependent Breast Cancer Cell Model.

Endocrine-disrupting compounds (EDC) play an important role in the increased incidence of breast cancer (BC). There are some 160 xenoestrogens that may be involved in the development of BC. Much less is known about the influence of xenoestrogens on the effectiveness of the treatment of BC. The aim of this study was to analyze the interaction of metalloestrogens (aluminum and chromium (III)) and drugs used in the treatment of hormone-dependent BC-aromatase inhibitors (AI)-letrozole and exemestane. A cell viability assay, a flow cytometer analysis of apoptosis and cell cycle phases, and protein activity of BAX and Bcl-2 were performed on two human breast cancer cell lines-MCF-7 and MCF-7/DOX. In MCF-7 cells, the lower concentration of exemestane and higher of letrozole, in combination with metalloestrogens, results in a decrease in the effectiveness of drugs. Additionally, in the MCF-7/DOX cell line, we observed that the combination of metalloestrogens and AI leads to a decrease in the drug's effectiveness due to an increase in the viability of breast cancer cells (both concentrations of letrozole and higher concentration of exemestane). In both cell lines, the reduction in the effectiveness of AI, in combination with metalloestrogens, is not related to the influence on the cell cycle. Our results confirm that exposure to metalloestrogens may negatively affect the effectiveness of hormone therapy with AI. Further studies are needed to fully explain the mechanism of these interactions.

Suppression of Insulin Receptor Substrate 1 Inhibits Breast Cancer Growth In Vitro and in Female Athymic Mice.

Targeting the type I insulin-like growth factor receptor (IGF-IR) has not been successful in breast cancer. Data suggest the highly homologous insulin receptor (IR) may be an alternate growth stimulatory pathway used by cancer cells. Since both receptors phosphorylate the insulin receptor substrate 1 (IRS-1) protein as an immediate consequence of ligand binding, disruption of both receptors could be accomplished by suppression of IRS-1. IRS-1 gene deletion by CRISPR/Cas9 editing resulted in suppression of IGF-I, insulin, and estrogen-stimulated growth in hormone-dependent MCF-7L breast cancer cells. A doxycycline-inducible IRS-1 shRNA lentiviral construct was also used to infect MCF-7L breast cancer cells. IRS-1 shRNA downregulation resulted in decreased responses to IGF-I, insulin, and estradiol in monolayer and anchorage-independent growth assays. Decreased IRS-1 levels also suppressed estradiol-stimulated gene expression and estrogen receptor binding to DNA. Xenograft growth was also inhibited by induction of IRS-1 shRNA. These data show that IRS-1 is a critical regulator of endocrine responsive breast cancer. Efforts to target this adaptor protein could have broader growth inhibitory effects and receptor targeting.

Honokiol inhibits the growth of hormone-resistant breast cancer cells: its promising effect in combination with metformin.

Primary and metastatic breast cancers still represent an unmet clinical need for improved chemotherapy and hormone therapy. Considerable attention has been paid to natural anticancer compounds, especially lignans. The study aimed to evaluate the activity of several lignans against breast cancer cells and assess the effect of leading lignans on signaling pathways in combination with metformin. Human breast cancer cell lines MCF7 (hormone-dependent), MDA-MB-231, and SKBR3 (hormone-independent) were used. A hormone-resistant MCF7/hydroxytamoxifen (HT) subline was obtained by long-term cultivation of the MCF7 line with hydroxytamoxifen. Antiproliferative activity was assessed by the MTT test; the expression of signaling pathway proteins was evaluated by immunoblotting analysis. We evaluated the antiproliferative activity of lignans in breast cancer cells with different levels of hormone dependence and determined the relevant IC50 values. Honokiol was chosen as the leading compound, and its IC50 ranged from 12 to 20 μM, whereas for other tested lignans, the IC50 exceeded 50 μM. The accumulation of cleaved PARP and a decrease in the expression of Bcl-2 and ERα in MCF7/HT were induced following the combination of honokiol with metformin. Honokiol demonstrated significant antiproliferative activity against both hormone-dependent breast cancer cells and lines with primary and acquired hormone resistance. The combination of honokiol with metformin is considered an effective approach to induce death in hormone-resistant cells. Honokiol is of interest as a natural compound with antiproliferative activity against breast cancers, including resistant tumors.

High Glucose Reduces Anti-Tumor Activity of Aromatase Inhibitors in a Hormone-Dependent Breast Cancer Cell Model

High Glucose Reduces Anti-Tumor Activity of Aromatase Inhibitors in a Hormone-Dependent Breast Cancer Cell Model

Arsenicum album Induces Cell Cycle Arrest and Apoptosis, and Inhibits Epithelial-Mesenchymal Transition in Hormone-Dependent MCF7 Breast Cancer Cells.

Arsenic trioxide (As2O3) has been in therapeutic use since the 18th century for various types of cancers including skin and breast; however, it gained popularity following FDA approval for its use against acute promyelocytic leukemia. This present work was designed to evaluate the anti-cancer potential of a homeopathic potency of arsenic trioxide (Arsenicum album 6C) in hormone-dependent breast cancer. Breast cancer cells (MCF7) were treated with Arsenicum album (Ars 6C) to evaluate its anti-proliferative and apoptotic potential. We examined the effect of Ars 6C on the cell cycle, wound healing, reactive oxygen species (ROS) generation, and modulation of expression of key genes which are aberrant in cancer. Treating breast cancer cells with Ars 6C halted the cell cycle at the sub-G0 and G2/M phases, which could be attributed to DNA damage induced by the generation of ROS. Apoptotic induction was associated with upregulation of Bax expression, with concurrent downregulation of the Bcl-2 gene. Ars 6C was also seen to reverse epithelial to mesenchymal transition and reduce the migration of breast cancer cells. The findings suggest that Ars has significant anti-proliferative and apoptotic potential against breast cancer cells. Further studies are required to elucidate the mechanism by which Ars exerts its effect in the in vivo setting.

ODP275 The Effects of Tris(2-Chloroethyl) phosphate (TCEP) on the Expression of Estrogen Receptor Alpha and Tumor Suppressor Gene BRCA-1 in Breast Cancer Cell Lines

Abstract TCEP is an organophosphorus flame-retardant (OPFR) that is used widely in polyurethane foams, furniture, and household products. From these products, TCEP has significant emission into its surrounding environment. Inhalation and dermal absorption are the most common routes of human exposure to OPFRs, which have been measured in human hair, breast milk, and urine. Previous studies of OPFRs have shown their endocrine disrupting actions that have influence on diseases such as cancer. Breast cancer is the second most common cancer among women in the United States, and because of this prevalence, it is imperative to investigate possible causes and treatments for this disease. Due to the endocrine disrupting nature of OPFRs, we are investigating the effects of TCEP on hormone dependent breast cancer cell lines MCF-7 and T-47D. Our study examines the effects of TCEP, alone and in combination with hormones and anti-hormones, on ERα and BRCA1 expression in MCF-7 and T-47D breast cancer cells by utilizing western blot analyses, cellular viability assays, confocal microscopy, apoptosis assays and RT-qPCR analyses. In order to deplete any endogenous steroids or effectors, breast cancer cells were cultured in a medium containing 5% charcoal-stripped fetal bovine serum for six days. Western blot analysis revealed alterations in the expression of ER-alpha after 24 hours of treatment with varying concentrations of TCEP (1µM-2mM). A concentration-dependent decrease of ERα protein levels was noted in the T-47D cell line when compared to the control. BRCA1 protein levels also displayed an altered expression compared to the control through the various concentrations of TCEP. Through our concentration studies, optimum concentrations of TCEP were found to be 100 µM for T-47D and 2mM for MCF-7. For our hormone studies, cell lines were treated with their respective optimum concentration of TCEP as well with combinations of hormones and anti-hormones. After 24-hour treatment of E 2, TCEP, and a combination of E2 with TCEP, a decrease in ERα expression was observed when compared to the control in both MCF-7 and T-47D cell lines. A combination of TCEP with ICI treatment revealed a significant down regulation of ERα expression level compared to the control. The same treatment conditions exhibited an increase with BRCA1 expression compared to the control and these effects were sensitive to the presence of antiestrogens in both cell lines. For cell viability studies, cells were treated for 6 days with TCEP concentrations ranging from 10nm-2µM which displayed an increase (40-50%) in cell proliferation compared to the control in both cell lines. Cytolocalization of ERα remained unaltered with the above treatment conditions. Our studies provide interesting findings about the molecular mechanisms of TECP as a potential endocrine disrupting compound on the steroid receptors and tumor suppressor genes in breast cancer cells. Presentation: No date and time listed