MDA-MB231 Triple Negative Breast Cancer Research Articles

Fractions of Methanol Extracts from the Resurrection Plant Haberlea rhodopensis Have Anti-Breast Cancer Effects in Model Cell Systems

Breast cancer is among the most problematic diseases and a leading cause of death in women. The methods of therapy widely used, so far, are often with many side effects, seriously hampering patients’ quality of life. To overcome these constraints, new cancer treatment alternatives are constantly tested, including bioactive compounds of plant origin. Our aim was to study the effects of Haberlea rhodopensis methanol extract fractions on cell viability and proliferation of two model breast cancer cell lines with different characteristics. In addition to the strong reduction in cell viability, two of the fractions showed significant influence on the proliferation rate of the hormone receptor expressing MCF7 and the triple negative MDA-MB231 breast cancer cell lines. No significant effects on the benign MCF10A cell line were observed. We applied a large scale non-targeted approach to purify and identify highly abundant compounds from the active fractions of H. rhodopensis extracts. By the combined NMR/MS approach, myconoside was identified in the fractions and hispidulin 8-C-(6-O-acetyl-2″-O-syringoyl-β-glucopyranoside) was found in one of them. We further performed molecular docking analysis of possible myconoside interactions with several proteins, important for breast cancer proliferation. High probability of binding was established for GLUT1 transporter, estrogen receptor and MYST acetyltransferase. Our results are a good background for future studies on the use of myconoside for targeted breast cancer therapy.

Antitumor Potential of Sericite Treatment Mediated by Cell Cycle Arrest in Triple-Negative MDA-MB231 Breast Cancer Cells.

Breast cancer is the most common cancer and the leading cause of cancer-related mortality among females worldwide. Triple-negative breast cancer (TNBC) accounts for about 10–15% of all breast cancers and is usually more aggressive and has a poorer prognosis. Sericite has been known to have antitumor and immune-stimulatory effects. Although the chemopreventive potential of sericite has been demonstrated in other cancers, its molecular pathways in TNBC still require investigation. Thus, in the present study, the antitumor mechanism of sericite against MDA-MB231 breast cancer cells was examined in vitro and in an in vivo xenograft mouse model. Sericite treatment reduced cell proliferation and cell proliferation marker proliferating cell nuclear antigen (PCNA) in MDA-MB231 cells. It also decreased the total cell number and arrested cells in the G0/G1 phase of the cell cycle with an increase in the phosphorylation of P53 and upregulation of cell cycle regulatory proteins P21 and P16. In addition, sericite treatment also induced apoptosis signaling, which was evident by the upregulation of apoptotic protein markers cleaved caspases 3 and 9. A reduction in reactive oxygen species (ROS), NADPH oxidase 4 (NOX4), p22phox, and heat shock proteins (HSPs) was also observed. Similar results were obtained in vivo with significantly reduced tumor volume in sericite-administered mice. Collectively, these findings suggest that sericite has antitumor potential based on its property to induce cell cycle arrest and apoptotic cell death and therefore could serve as a potential therapeutic agent and crucial candidate in anticancer drug development for TNBC.

DR5 antibody conjugated lipid-based nanocarriers of gamma-secretase inhibitor for the treatment of triple negative breast cancer

In the present study, Death receptor-5 (DR5) antibody conjugated solid lipid nanoparticles (DR5-DAPT-SLNs) has been formulated for effective intracellular of γ-secretase inhibitor, N-[N-(3,5-Difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) to cancer cells. Emulsification-solvent evaporation, followed by EDC cross-linking methods, was employed to prepare DR5 targeted DAPT-SLNs (DR5-DAPT-SLNs). The formulation was characterized by its particle size, shape, and surface charge. The in vitro &in vivo anticancer efficacy was studied in MDA-MB231 triple negative breast cancer (TNBC) cells and DMBA induced breast cancer model in mice, respectively. The results show that thatDR5-DAPT-SLNs is found to be a spherical shape with an average particle size of 187 ± 0.98 nm and having an average surface charge of 23 ± 2.3 mV. DR5-DAPT-SLNs have higher cytotoxicity in MDA-MB231 cells compared to DAPT-SLNs (non-targeted) and the bulk drug. However, in DR5 negative HEK 293 noncancer cells, the formulation shows minimal cytotoxic effects. The above results, therefore, demonstrate DR5 mediated uptake is responsible for improved cytotoxicity of DAPT. In the in vivo anticancer study, DR5-DAPT-SLNs show greater tumor regression when compared to DAPT-SLNs and the bulk drug. In conclusion, the results of the present study demonstrate that the DR5-DAPT-SLNs selectively target cancer cells and potentiate the anticancer efficacy of DAPT against TNBC cells.

Abstract 4362: Combination of conventional therapies and antiandrogenic treatments as a succesful tool for triple negative breast cancer (TNBC) treatment

Abstract Triple negative breast cancer (TNBC) patients do not benefit from conventional hormonal therapies due to the loss of expression of ER, PR, and HER2. Therefore, the usual adjuvant treatments for breast cancer, are not applied to TNBC. Recently, it has been found that approximately one third of TNBC tumours express androgen receptor (AR) and it is associated with better response to endocrine therapies. However, the prognostic value of AR expression in TNBC is still unclear. Therefore, in this preliminary study we evaluate the effectiveness of an anti-androgen treatment (bicalutamide) respect to conventional treatments (doxorubicin and lapatinib) in TNBC human cell lines and their corresponding xenografts. Briefly, SUM149, SUM159 and MDAMB231 TNBC cell lines were cultured in supplemented medium. Cells were plated in 96-well plates and a serial dilution of Doxorubicin, Lapatinib, Bicatulamide and respective combinations were added. In addition, 106 cells were implanted subcutaneosly into five female mice (Balb/C SCID). When tumors developed, mice were treated with doxorubicin, bicalutamide, doxorubicin + bicalutamide and doxorubicin + bicalutamide + lapatinib. Every treatment was perfomed every 3 days during 15 days and tumor reduction and appearance of metastases were evaluated. Results from cell culture showed that neoplasic cells from each cell line were high sensitive to bicalutamide treatment (SUM149 EC50: 9,860e009; MDAMB231 EC50: 9,454e009; SUM159 EC50: 2,170e009). Also, viability decreased when we added an anti-androgen (bicalutamide) to the conventional treatments (doxorubicin + lapatinib). In vivo experiments revealed a greater percentage of tumour reduction (around 70%) in mice treated with combination of treatments and a lower appearance of metastasis was observed in this group respect to control group (SUM149: 40% vs 60%; MDA-MB-231: 20% vs 75%; SUM159: 20% vs 60%). Therefore, our preliminary findings suggest that the addition of an anti-androgenic agent to treatments currently in use can reduce the tumour considerably, defining anti-androgenic treatments as a novel effective therapeutic target. Citation Format: Sara Caceres, Angela Alonso Diez, Gema Silvan, Maria J. Illera, Juan C. Illera. Combination of conventional therapies and antiandrogenic treatments as a succesful tool for triple negative breast cancer (TNBC) treatment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4362.

A Triple Combination of Metformin, Acetylsalicylic Acid, and Oseltamivir Phosphate Impacts Tumour Spheroid Viability and Upends Chemoresistance in Triple-Negative Breast Cancer.

IntroductionTargeted multimodal approaches need to be strategically developed to control tumour growth and prevent metastatic burden successfully. Breast cancer presents a unique clinical problem because of the variety of cellular subtypes that arise. The tumour stage and cellular subtypes often dictate the appropriate clinical treatment regimen. Also, the development of chemoresistance is a common clinical challenge with breast cancer. Higher doses and additional drug agents can produce additional adverse effects leading to a more aggressive malignancy. Acetylsalicylic acid (ASA), metformin (Met), and oseltamivir phosphate (OP) were investigated for their efficacy to sensitize MDA-MB-231 triple-negative breast cancer and its tamoxifen (Tmx) resistant variant (MDA-MB-231-TmxR) together in combination with Tmx treatment.MethodsMicroscopic imaging, the formation of 3D multicellular tumour spheroids, immunocytochemistry, flow cytometry, Annexin V Assay, Caspase 3/7 Apoptosis Assay, tube formation assay and analysis, and WST-1 cell viability assay evaluated the formation of MCTS, morphologic changes, cell viability, apoptosis activity and the expression levels of ALDH1A1, CD44 and CD24 on the cell surface, MDA-MB231 triple-negative breast cancer, tamoxifen (Tmx) resistant variant (MDA-MB-231-TmxR).ResultsThe results using a triple combination of ASA, Met and OP on MDA-MB-231 and MDA-MB-231-TmxR cells and their matrix-free 3D multicellular tumour spheroids (MCTS) formed by using the cyclic Arg-Gly-Asp-D-Phe-Lys peptide modified with 4-carboxybutyl-triphenylphosphonium bromide (cyclo-RGDfK(TPP)) peptide method demonstrate a consistent and significant decrease in cell and tumour spheroid viability and volume with increased apoptotic activity, and increased sensitivity to Tmx therapy. Tmx treatment of MDA-MB-231 cells in combination with ASA, Met and OP markedly reduced the CD44/CD24 ratio by 6.5-fold compared to the untreated control group. Tmx treatment of MDA-MB-231-TmxR cells in combination with ASA, Met and OP markedly reduced the ALDH1A1 by 134-fold compared to the same treatment for the parental cell line. Also, the triple combination treatment of ASA, Met, and OP inhibited vasculogenic endothelial cell tube formation and induced endothelial cell apoptosis.ConclusionFor the first time, the findings demonstrate that repurposing ASA, Met, and OP provides a novel and promising targeted multimodal approach in the treatment of triple-negative breast cancer and its chemoresistant variant.

Abstract P4-08-05: Novel tumor suppressor regulating the PI3K/AKT pathway in triple negative breast cancer (TNBC)

Abstract The PI3K/AKT signaling pathway is a known oncogenic pathway in breast cancer, involved in essential cellular processes necessary for cancer development and progression, including altered proliferation, metabolism, and cell survival. Mutations in this pathway occur in 20% of all TNBC cases, making it the most deregulated pathway in the only subclass of breast cancer with no targeted therapy. Few clinical trials testing PI3K/AKT pathway inhibition in these breast cancers have shown limited long term efficacy; the heterogeneity of tumors and variable response rates in clinical studies underscore the necessity to better understand the mechanisms governing TNBC and the PI3K/AKT pathway in order to predict patient response to targeted therapies. In particular, appropriate biomarkers are required to identify the tumor subtypes that may be more responsive to PI3K pathway inhibition. While regulation of AKT activation through a classic phosphorylation signaling cascade is well understood, recent studies have revealed a non-canonical pathway contributing to regulate AKT activation and possibly providing an unexpected mechanism for resistance to PI3K inhibition. Non-canonical regulation of AKT is provided by non-proteolytic ubiquitination of AKT favoring its recruitment to the plasma membrane and leading to hyperactivation, but a full understanding of the mechanism and players involved in this process is missing. Our lab has recently identified G-Protein Pathway Suppressor 2 (GPS2) as a novel regulator of the insulin signaling pathway through the inhibition of AKT ubiquitination in the adipose tissue. Here, we explore the role of GPS2 as a tumor suppressor in the context of breast cancer. Deletion of GPS2 in aggressive MDA-MB231 TNBC cells results in increased AKT phosphorylation associated with greater proliferation, migration and invasion in vitro, with all phenotypes mitigated in presence of the allosteric AKT inhibitor MK2206.Transcriptomic profiling of wild-type MB231, MB231-GPS2-KO, and myristoylated AKT (MB231-myrAKT) revealed a significant overlap between the MB231-GPS2-KO and myrAKT signatures. Conversely, deletion of GPS2 in MDA-MB468, a TNBC cell line with an activating mutation in the PI3K/AKT pathway, do not show any increase in proliferation, migration or invasion, but remain sensitive to AKT inhibition. Together these results indicate that loss of GPS2-mediated inhibition of AKT ubiquitination is sufficient to drive activation of the PI3K/AKT pathway in absence of other activating mutations. Furthermore, preliminary analysis of an orthotopic model of MB231-GPS2-KO cells in NOD scid gamma (NSG) mice resulted in greater breast tumor sizes when compared to the parental cell line, confirming GPS2 putative tumor suppressor role in vivo. Further studies are required to investigate GPS2 expression levels and mutational status in tumor samples, and to confirm GPS2 relevance as a predictive biomarker for treatment outcome, thus exposing an additional category of tumors that could be responsive to PI3K/AKT class inhibition and/or would benefit from alternative strategies to prevent resistance. Citation Format: Stefanie Chan, Emma Smith, Stefano Monti, M Dafne Cardamone, Valentina Perissi. Novel tumor suppressor regulating the PI3K/AKT pathway in triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-08-05.

Design, synthesis, and biological evaluation of new 6,N 2-diaryl-1,3,5-triazine-2,4-diamines as anticancer agents selectively targeting triple negative breast cancer cells.

New 6,N2-diaryl-1,3,5-triazine-2,4-diamines were designed using the 3D-QSAR model developed earlier. These compounds were prepared and their antiproliferative activity was evaluated against three breast cancer cell lines (MDA-MB231, SKBR-3 and MCF-7) and non-cancerous MCF-10A epithelial breast cells. The synthesized compounds demonstrated selective antiproliferative activity against triple negative MDA-MB231 breast cancer cells. The most active compound in the series inhibited MDA-MB231 breast cancer cell growth with a GI50 value of 1 nM. None of the tested compounds significantly affected the growth of the normal breast cells. The time-dependent cytotoxic effect, observed when cytotoxicity was assessed at different time intervals after the treatment, and morphological features, observed in the fluorescence microscopy and live cell imaging experiments, suggested apoptosis as the main pathway for the antiproliferative activity of these compounds against MDA-MB231 cells.

6,N 2-Diaryl-1,3,5-triazine-2,4-diamines: synthesis, antiproliferative activity and 3D-QSAR modeling.

A library of 126 compounds with a 6,N2-diaryl-1,3,5-triazine-2,4-diamine scaffold was prepared using a one-pot, microwave-assisted method from readily available cyanoguanidine, aromatic aldehydes and arylamines. The three-component condensation of these reagents in the presence of hydrochloric acid was followed by the treatment with a base, which promoted a rearrangement of the dihydrotriazine ring and its dehydrogenative aromatization. The antiproliferative properties of the prepared compounds were evaluated using three breast cancer cell lines. The most promising results were obtained in the growth inhibition of the triple negative MDA-MB231 breast cancer cells. The active compounds were also selective against cancer cells and did not affect growth of the non-cancerous MCF-10A breast cell line. Analyzing the structure–activity relationship within the series, we built a 3D-QSAR model for the further design of more potent anticancer compounds.

Discovery of holoenzyme-disrupting chemicals as substrate-selective CK2 inhibitors

CK2 is a constitutively active protein kinase overexpressed in numerous malignancies. Interaction between CK2α and CK2β subunits is essential for substrate selectivity. The CK2α/CK2β interface has been previously targeted by peptides to achieve functional effects; however, no small molecules modulators were identified due to pocket flexibility and open shape. Here we generated numerous plausible conformations of the interface using the fumigation modeling protocol, and virtually screened a compound library to discover compound 1 that suppressed CK2α/CK2β interaction in vitro and inhibited CK2 in a substrate-selective manner. Orthogonal SPR, crystallography, and NMR experiments demonstrated that 4 and 6, improved analogs of 1, bind to CK2α as predicted. Both inhibitors alter CK2 activity in cells through inhibition of CK2 holoenzyme formation. Treatment with 6 suppressed MDA-MB231 triple negative breast cancer cell growth and induced apoptosis. Altogether, our findings exemplify an innovative computational-experimental approach and identify novel non-peptidic inhibitors of CK2 subunit interface disclosing substrate-selective functional effects.

Effect of hypoxia on human equilibrative nucleoside transporters hENT1 and hENT2 in breast cancer.

Elevated proliferation rates in cancer can be visualized with positron emission tomography (PET) using 3'-deoxy-3'-l-[18F]fluorothymidine ([18F]FLT). This study investigates whether [18F]FLT transport proteins are regulated through hypoxia. Expression and function of human equilibrative nucleoside transporter (hENT)-1, hENT2, and thymidine kinase 1 (TK1) were studied under normoxic and hypoxic conditions, and assessed with [18F]FLT-PET in estrogen receptor positive (ER+)-MCF7, triple-negative MDA-MB231 breast cancer (BC) cells, and MCF10A cells (human mammary epithelial cells). Functional involvement of hENT2 [18F]FLT transport was demonstrated in all cell lines. In vitro [18F]FLT uptake was higher in MDA-MB231 than in MCF7: 242 ± 9 vs. 147 ± 18% radioactivity/mg protein after 60 min under normoxia. Hypoxia showed no significant change in radiotracer uptake. Protein analysis revealed increased hENT1 (P < 0.0963) in MDA-MB231. Hypoxia did not change expression of either hENT1, hENT2, or TK1. In vitro inhibition experiments suggested involvement of hENT1, hENT2, and human concentrative nucleoside transporters during [18F]FLT uptake into all cell lines. In vivo PET imaging revealed comparable tumor uptake in MCF7 and MDA-MB231 tumors over 60 min, reaching standardized uptake values of 0.96 ± 0.05 vs. 0.89 ± 0.08 (n = 3). Higher hENT1 expression in MDA-MB231 seems to drive nucleoside transport, whereas TK1 expression in MCF7 seems responsible for comparable [18F]FLT retention in ER+ tumors. Our study demonstrates that hypoxia does not significantly affect nucleoside transport as tested with [18F]FLT in BC.-Krys, D., Hamann, I., Wuest, M., Wuest, F. Effect of hypoxia on human equilibrative nucleoside transporters hENT1 and hENT2 in breast cancer.

Cytotoxic Potential of the Coelomic Fluid Extracted from the Sea Cucumber Holothuria tubulosa against Triple-Negative MDA-MB231 Breast Cancer Cells.

Growing evidence has demonstrated that the extracts of different holothurian species exert beneficial effects on human health. Triple negative breast cancers (TNBC) are highly malignant tumors that present a poor prognosis due to the lack of effective targeted therapies. In the attempt to identify novel compounds that might counteract TNBC cell growth, we studied the effect of the exposure of the TNBC cell line MDA-MB231 to total and filtered aqueous extracts of the coelomic fluid obtained from the sea cucumber Holoturia tubulosa, a widespread species in the Mediterranean Sea. In particular, we examined cell viability and proliferative behaviour, cell cycle distribution, apoptosis, autophagy, and mitochondrial metabolic/cell redox state. The results obtained indicate that both total and fractionated extracts are potent inhibitors of TNBC cell viability and growth, acting through both an impairment of cell cycle progression and mitochondrial transmembrane potential and a stimulation of cellular autophagy, as demonstrated by the increase of the acidic vesicular organelles and of the intracellular protein markers beclin-1, and total LC3 and LC3-II upon early exposure to the preparations. Identification of the water-soluble bioactive component(s) present in the extract merit further investigation aiming to develop novel prevention and/or treatment agents efficacious against highly metastatic breast carcinomas.

A Rab4‐Regulated Endosomal Compartment Prolongs EGFR Activation in Breast Cancer Cells

Early sorting endosomes are responsible for the proper trafficking of membrane-bound receptors that can drive cancer progression. However, the morphology, cargo sorting and signaling of early endosomes remains poorly understood in breast cancer. We have identified a novel population of enlarged early endosomal vesicles in breast cancer cells and human tumor xenografts (MDAMB231 and T47D) but not in non-cancerous epithelial cells (MCF10A) using confocal and super-resolution 3D dSTORM microscopy. A detailed quantitative analysis of the whole-cell endosomal morphology, cargo sorting, maturation, and regulatory Rab-GTPases associated with this compartment in cancerous breast epithelial cell lines was performed using Airyscan microscopy and 3D rendering approaches. This analysis showed that highly aggressive triple negative MDAMB231 breast cancer cells have larger but significantly fewer EEA1-enriched early sorting endosomes compared to non-cancerous MCF10A cells. Furthermore, live-cell time-lapse imaging showed that, despite normal transferrin recycling, the epidermal growth factor (EGF) and transferrin are found together in these large endosomal vesicles following internalization in MDAMB231 but not in MCF10A cells. Most importantly, these large EEA1-positive MDAMB231 endosomes exhibited prolonged EGF-induced activation of EGFR (p1068). We investigated the role of Rab4-mediated changes on endosome structure and function and found that over-expression of wild-type Rab4 in non-cancerous MCF10A cells produced similar EEA1-positive enlarged early-endosomes with prolonged EGF induced EGFR activation (p1068). Rab4 mutants in dominant-negative or constitutively-active state did not elicit the same effects as the wild-type Rab4, indicating that the on-off cycling of Rab4 is critical for the regulation of endosomal size and number. These large endosomes contain adjacent Rab4 and Rab11 domains, are located primarily at the perinuclear region and can undergo actin-associated budding events to recycle cargo out towards the plasma membrane. Altogether, this extensive characterization of early-endosomes in breast cancer cells has identified a novel Rab4 regulated enlarged endocytic compartment leading to prolonged EGFR activation. Interestingly, our data suggests that a population of “pre-existent” large EEA1-containing endosomes is present in some breast cancer cells, challenging the current views of endosome biogenesis. This research is essential to determining receptor regulation in translational breast cancer models which can impact the optimization of anti-cancer human therapies. Alterations in endocytic regulation in cancer cells may be key to understanding the adaptability of cancer cells and lead to new therapeutic targets. Support or Funding Information This work was supported by the National Institute of Health (NIH) R01 BRG CA20772 Breast cancer cells have altered early-endocytic morphology Representative images from whole-cell Airyscan microscopy assay to quantitatively characterize early-endocytic morphology (with respect to whole-cell morphology) in non-cancerous breast epithelial cells (MCF10A)and breast cancer cell lines (MDAMB231 and T47D) with 3D rendering techniques. Example image from live-cell 4D imaging of endosomal dynamics that facilitates our comprehensive characterization of Rab4-regulated endosomes in breast cancer cells. Prolonged EGF-induced EGFR activation (p1068) in MDAMB231 compared to MCf10A This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Molecular Signatures Associated with Treatment of Triple-Negative MDA-MB231 Breast Cancer Cells with Histone Deacetylase Inhibitors JAHA and SAHA.

Jay Amin hydroxamic acid (JAHA; N8-ferrocenylN1-hydroxy-octanediamide) is a ferrocene-containing analogue of the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA). JAHA's cytotoxic activity on MDA-MB231 triple negative breast cancer (TNBC) cells at 72 h has been previously demonstrated with an IC50 of 8.45 μM. JAHA's lethal effect was found linked to perturbations of cell cycle, mitochondrial activity, signal transduction, and autophagy mechanisms. To glean novel insights on how MDA-MB231 breast cancer cells respond to the cytotoxic effect induced by JAHA, and to compare the biological effect with the related compound SAHA, we have employed a combination of differential display-PCR, proteome analysis, and COMET assay techniques and shown some differences in the molecular signature profiles induced by exposure to either HDACis. In particular, in contrast to the more numerous and diversified changes induced by SAHA, JAHA has shown a more selective impact on expression of molecular signatures involved in antioxidant activity and DNA repair. Besides expanding the biological knowledge of the effect exerted by the modifications in compound structures on cell phenotype, the molecular elements put in evidence in our study may provide promising targets for therapeutic interventions on TNBCs.

Oxidative stress and breast cancer biomarkers: the case of the cytochrome P450 2E1

Aim: The aim of the study is to investigate the impact of the cytochrome P450 2E1, which is the most efficient CYP450 family member in generating reactive oxygen species (ROS), on cellular energy metabolism of breast cancer cells and therefore the effects of CYP2E1 on breast carcinogenesis. Methods: The estrogen receptor positive MCF-7 and the triple negative MDAMB- 231 breast cancer cells were used as experimental system to estimate ROS generation in these cells overexpressing CYP2E1 and treated with the glycolytic inhibitors 3-bromopyruvate or 2-deoxyglucose in the presence or absence of the CYP2E1 inhibitor chlormethiazole. Adenosine triphosphate (ATP) assay was used to measure ATP production and lactate assay to quantify the efflux of lactic acid in breast cancer cells treated with the CYP2E1 inhibitor chlormethiazole, the mitochondrial membrane potential and cell viability assays were employed to assess the pathway of cellular energy production and cellular death respectively after treatment of MCF-7 and MDA-MB-231 with the CYP2E1 activator acetaminophen or the CYP2E1 inhibitor chlormethiazole. Results: T he r esults i ndicated i ncreased ROS generation i n b reast c ancer c ells overexpressing C YP2E1. ROS generation was differentially regulated in breast cancer cells upon treatment with the CYP2E1 inhibitor chlormethiazole. Chlormethiazole treated MCF-7 cells exhibited reduced lactate efflux implying that CYP2E1 directly or indirectly regulates the glycolytic rate in these cells. Furthermore the mitochondrial membrane potential of both MCF-7 and MDA-MB-231 cells was differentially affected by the CYP2E1 activator acetaminophen versus the CYP2E1 inhibitor chlormethiazole providing additional support for the involvement of CYP2E1 in energy metabolic pathways in breast cancer. Conclusion: Results presented in this study provide evidence to suggest that CYP2E1 regulates cellular energy metabolism of breast cancer cells in a manner dependent on cell type and potentially on the clinical staging of the disease therefore CYP2E1 is a possible breast cancer biomarker.

The Histone Deacetylase Inhibitor JAHA Down-Regulates pERK and Global DNA Methylation in MDA-MB231 Breast Cancer Cells.

The histone deacetylase inhibitor N1-(ferrocenyl)-N8-hydroxyoctanediamide (JAHA) down-regulates extracellular-signal-regulated kinase (ERK) and its activated form in triple-negative MDA-MB231 breast cancer cells after 18 h and up to 30 h of treatment, and to a lesser extent AKT and phospho-AKT after 30 h and up to 48 h of treatment. Also, DNA methyltransferase 1 (DNMT1), 3b and, to a lesser extent, 3a, downstream ERK targets, were down-regulated already at 18 h with an increase up to 48 h of exposure. Methylation-sensitive restriction arbitrarily-primed (MeSAP) polymerase chain reaction (PCR) analysis confirmed the ability of JAHA to induce genome-wide DNA hypomethylation at 48 h of exposure. Collective data suggest that JAHA, by down-regulating phospho-ERK, impairs DNMT1 and 3b expression and ultimately DNA methylation extent, which may be related to its cytotoxic effect on this cancer cytotype.

Abstract 2931: Calmodulin-DR5 binding in breast cancer: Independent of TRA-8 sensitivity

Abstract Breast cancer is estimated to be the leading cause of new cancer cases and second in cancer related deaths among American women (Cancer: 63, 1153-1154, 2013). Classification of breast cancers into receptor-based subtypes, including estrogen receptor (ER) positive or triple negative breast cancers, establish targets that guide individualized treatment for patients (J Clin Oncol: 27,1153-1154, 2009). Drug resistant ER positive breast cancers and triple-negative breast cancers are prolific breast cancers with poor clinical outcome. TRA-8 is a death receptor-5 (DR5) specific agonistic antibody with tumoricidal activity in vitro and in vivo without inducing normal hepatocyte apoptosis (Nature Med: 7, 954-960, 2001). ER positive and triple negative breast cancer cell lines have a range of in vitro sensitivity to TRA-8 mediated cytotoxicity (Clin Cancer Res: 9, 3731-3741, 2003, Breast Cancer Res Treat: 133, 417-426, 2012). Calmodulin (CaM) is overexpressed in breast cancer (J Clin Oncol: 4, 994-1012, 1986, Cancer Res: 42, 2571-2574, 1982). Our lab has shown CaM binds to DR5 and plays a role in DR5 mediated DISC formation in ER positive MCF-7 and triple negative MDA-MB231 breast cancer cell lines (Proc. AACR; 2014, Abstract nr 2282). The goal of this study is to characterize an interaction between CaM and DR5 in a panel of ER positive and triple negative breast cancer cell lines representing a range of sensitivity to TRA-8 mediated cytotoxicity. CaM-DR5 interaction was characterized in a panel of triple negative breast cancer cell lines: MDA-MB-231, MDA-MB-468, HCC1937, and HCC1143 and ER positive breast cancer cell lines: ZR-75-1, T47D, and MCF-7 representing the range of sensitivity to TRA-8 (Clin Cancer Res: 9, 3731-3741, 2003, Breast Cancer Res Treat: 133, 417-426 2012). DR5 was immunoprecipitated, using TRA-8 conjugated beads, from the panel of breast cancer cell lines lysates. CaM co-immunoprecipitated with DR5 from all breast cancer cell lines lysates, showing endogenous CaM and DR5 form a complex. CaM pull-down of DR5 from the breast cancer lysates in the presence of 1 mM Ca2+ or 2 mM EGTA showed CaM/DR5 interaction is calcium dependent. We present evidence for a Ca2+ dependent interaction between CaM and DR5 in a panel of ER positive and triple negative breast cancer cell lines independent of TRA-8 sensitivity. Results from this study provide the basis to further characterization of CaM-DR5 interactions and to investigate the role of CaM/DR5 binding in DR5-mediated DISC formation, which could lead to novel strategies to overcome drug resistance in breast cancers. Results suggest that direct interaction between CaM and DR5 could represent a potential site for breast cancer chemotherapeutics. Citation Format: Romone M. Fancy, Donald J. Buchsbaum, Tong Zhou, Yuhua Song. Calmodulin-DR5 binding in breast cancer: Independent of TRA-8 sensitivity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2931. doi:10.1158/1538-7445.AM2015-2931

Cytotoxicity of the Urokinase-Plasminogen Activator Inhibitor Carbamimidothioic Acid (4-Boronophenyl) Methyl Ester Hydrobromide (BC-11) on Triple-Negative MDA-MB231 Breast Cancer Cells.

BC-11 is an easily synthesized simple thiouronium-substituted phenylboronic acid, which has been shown to be cytotoxic on triple negative MDA-MB231 breast cancer cells by inducing a perturbation of cell cycle when administered at a concentration equal to its ED50 at 72 h (117 μM). Exposure of cells to BC-11, either pre-absorbed with a soluble preparation of the N-terminal fragment of urokinase-plasminogen activator (uPa), or in co-treatment with two different EGFR inhibitors, indicated that: (i) BC-11 acts via binding to the N-terminus of the enzyme where uPa- and EGF receptor-recognizing sites are present, thereby abrogating the growth-sustaining effect resulting from receptor binding; and (ii) the co-presence of the EGFR inhibitor PD153035 potentiates BC-11’s cytotoxicity. Exposure of cells to a higher concentration of BC-11 corresponding to its ED75 at 72 h (250 μM) caused additional impairment of mitochondrial activity, the production of reactive oxygen species and promotion of apoptosis. Therefore, BC-11 treatment appears to show potential for the development of this class of compounds in the prevention and/or therapy of “aggressive” breast carcinoma.

Parthenolide generates reactive oxygen species and autophagy in MDA-MB231 cells. A soluble parthenolide analogue inhibits tumour growth and metastasis in a xenograft model of breast cancer

Triple-negative breast cancers (TNBCs) are clinically aggressive forms associated with a poor prognosis. We evaluated the cytotoxic effect exerted on triple-negative MDA-MB231 breast cancer cells both by parthenolide and its soluble analogue dimethylamino parthenolide (DMAPT) and explored the underlying molecular mechanism. The drugs induced a dose- and time-dependent decrement in cell viability, which was not prevented by the caspase inhibitor z-VAD-fmk. In particular in the first hours of treatment (1–3 h), parthenolide and DMAPT strongly stimulated reactive oxygen species (ROS) generation. The drugs induced production of superoxide anion by activating NADPH oxidase. ROS generation caused depletion of thiol groups and glutathione, activation of c-Jun N-terminal kinase (JNK) and downregulation of nuclear factor kB (NF-kB). During this first phase, parthenolide and DMAPT also stimulated autophagic process, as suggested by the enhanced expression of beclin-1, the conversion of microtubule-associated protein light chain 3-I (LC3-I) to LC3-II and the increase in the number of cells positive to monodansylcadaverine. Finally, the drugs increased RIP-1 expression. This effect was accompanied by a decrement of pro-caspase 8, while its cleaved form was not detected and the expression of c-FLIPS markedly increased. Prolonging the treatment (5–20 h) ROS generation favoured dissipation of mitochondrial membrane potential and the appearance of necrotic events, as suggested by the increased number of cells positive to propidium iodide staining. The administration of DMAPT in nude mice bearing xenografts of MDA-MB231 cells resulted in a significant inhibition of tumour growth, an increment of animal survival and a marked reduction of the lung area invaded by metastasis. Immunohistochemistry data revealed that treatment with DMAPT reduced the levels of NF-kB, metalloproteinase-2 and -9 and vascular endothelial growth factor, while induced upregulation of phosphorylated JNK. Taken together, our data suggest a possible use of parthenolide for the treatment of TNBCs.

Cytotoxic Effects of Jay Amin Hydroxamic Acid (JAHA), a Ferrocene-Based Class I Histone Deacetylase Inhibitor, on Triple-Negative MDA-MB231 Breast Cancer Cells

The histone deacetylase inhibitors (HDACis) are a class of chemically heterogeneous anticancer agents of which suberoylanilide hydroxamic acid (SAHA) is a prototypical member. SAHA derivatives may be obtained by three-dimensional manipulation of SAHA aryl cap, such as the incorporation of a ferrocene unit like that present in Jay Amin hydroxamic acid (JAHA) and homo-JAHA [ Spencer , et al. ( 2011 ) ACS Med. Chem. Lett. 2 , 358 - 362 ]. These metal-based SAHA analogues have been tested for their cytotoxic activity toward triple-negative MDA-MB231 breast cancer cells. The results obtained indicate that of the two compounds tested, only JAHA was prominently active on breast cancer cells with an IC(50) of 8.45 μM at 72 h of treatment. Biological assays showed that exposure of MDA-MB231 cells to the HDACi resulted in cell cycle perturbation with an alteration of S phase entry and a delay at G(2)/M transition and in an early reactive oxygen species production followed by mitochondrial membrane potential (MMP) dissipation and autophagy inhibition. No annexin binding was observed after short- (5 h) and longer (24 and 48 h) term incubation with JAHA, thereby excluding the promotion of apoptosis by the HDACi. Although caution must be exercised in extrapolation of in vitro results to the in vivo situation for which research on animals and human trials are needed, nevertheless JAHA treatment possesses the potential for its development as an agent for prevention and/or therapy of "aggressive" breast carcinoma, thus prompting us to get more insight into the molecular basis of its antibreast cancer activity.