Estrogen receptor α K303R mutation reorganizes its binding to forkhead box protein A1 regions and induces chromatin opening.

BACKGROUND: Estrogen receptor alpha (ERα) is a frequently mutated gene in breast cancer (BC). While many studies have investigated molecular dysregulation by hotspot mutations at Y537 and D538, which exhibit an estrogen-independent constitutively active phenotype, the functional abnormalities of other mutations remain obscure. The K303R mutation in primary invasive BC has been implicated with endocrine resistance, tumor size, and lymph node positivity. However, the impact of the K303R mutation on the cell epigenome is yet unknown. METHODS AND RESULTS: We introduced the K303R ERα mutant in ERα-negative MDA-MB-453 cells to monitor ERα-dependent transactivation and to perform epigenomic analyses. ATAC-seq and ChIP-Seq analyses indicated that both wild-type (WT) and the K303R mutant associated with Forkhead box (Fox) protein family motif regions at similar rates, even without an ERα-binding sequence, but only the K303R mutant induced chromatin opening at those regions. Biochemical analyses demonstrated that the WT and the K303R mutant can be tethered on DNA by FoxA1 indirectly, but only the K303R/FoxA1/DNA complex can induce associations with the nuclear receptor cofactor 2 (NCOA2). CONCLUSIONS: These findings suggest that the K303R mutant induces chromatin opening at the Fox binding region through the FoxA1-dependent associations of the K303R mutant to NCOA2 and then probably disrupts the regulation of Fox-target genes, resulting in K303R-related BC events.

The Association of RGS2 and Slug in the Androgen-induced Acquisition of Mesenchymal Features of Breast MDA-MB-453 Cancer Cells.

BACKGROUND: Epithelial-mesenchymal transition (EMT) of tumor cells is a prerequisite to cancer cell invasion and metastasis. This process involves a network of molecular alterations. Androgen receptor (AR) plays an important role in the biology of breast cancers, particularly those dependent on AR expression like luminal AR (LAR) breast cancer subtype. We have recently reported that the AR agonist, dihydrotestosterone (DHT), induces a mesenchymal transition of MDA-MB-453 cells, concomitant with transcriptional up-regulation of Slug and regulator of G protein signaling 2 (RGS2). OBJECTIVE: The role of Slug and RGS2 in mediating the DHT-induced effects in these cells was investigated. METHODS: MDA-MB-453 cells were used as a model system of LAR breast cancer. Immunofluorescence was used to examine cell morphology and protein localization. Protein expression was analyzed by immunoblotting. Protein localization was confirmed by cell fractionation followed by immunoblotting. Protein-protein interaction was confirmed by co-immunoprecipitation followed by immunoblotting. Transwell membranes were used to assess cell migration. Transfection of cells with siRNA molecules that target Slug and RGS2 mRNA was utilized to delineate the modes of action of these two molecules. RESULTS: Treatment of MDA-MB-453 cells with DHT induced the expression of both proteins. In addition, AR-Slug, AR-RGS2, and Slug-RGS2 interactions were observed shortly after AR activation. Knocking down Slug abrogated the basal, but not the DHT-induced, cell migration and blocked DHT-induced mesenchymal transition. On the other hand, RGS2 knocked-down cells had an increased level of Slug protein and assumed mesenchymal cell morphology with induced migration, and the addition of DHT further elongated cell morphology and stimulated their migration. Inhibition of AR or ß-catenin reverted the RGS2 knocked-down cells to the epithelial phenotype, but only inhibition of AR blocked their DHT-induced migration. CONCLUSIONS: These results suggest the involvement of RGS2 and Slug in a complex molecular network regulating the DHT-induced mesenchymal features in MDA-MB-453 cells. The study may offer a better understanding of the biological role of AR in breast cancer toward devising AR-based therapeutic strategies.

Involvement of ß-catenin in Androgen-induced Mesenchymal Transition of Breast MDA-MB-453 Cancer Cells.

Purpose The cellular and molecular dynamics of DHT-induced EMT in MDA-MB-453 cells were investigated.Methods:PCR arrays were used to examine the expression of EMT-regulatory genes. Immunoblotting was used to detect protein levels and confirm protein-protein interaction following immunoprecipitation. Immunofluorescence was used to observe rearrangement of the actin cytoskeleton and cell morphology. Cell migration was assessed by transwell assayResults: Change of cell morphology was concomitant with increased cell migration after treating cells with DHT. Exposure of cells to DHT for one hour was sufficient to induce changes in cell morphology and actin cytoskeleton after 72 hours indicating altered gene expression. A long-term lasting nuclear translocation of AR was observed after a short exposure of cells to DHT. Investigating the expression of 84 EMT-related genes revealed down-expression of ß-catenin, N-cadherin, and TCF-4 and increased expression of Slug, all of which were confirmed at the protein level. Yet, not only early interaction of AR and ß-catenin was observed following AR activation, inhibition of ß-catenin blocked DHT-induced mesenchymal transition and migration. Wnt signaling was found to be partially important in DHT-induced morphological alteration. The mesenchymal transition of cells could be induced by treating cells with an inhibitor of glycogen synthase kinase-3ß, an enzyme that inhibits ß-catenin; this morphological transition could be reversed by antagonizing AR suggesting that AR functions downstream of ß-catenin.Conclusions: These results suggest that MDA-MB-453 cells undergo partial EMT induced by DHT, ß-catenin is critical for this phenotypic change, and AR probably reciprocally mediates the mesenchymal transition of these cells upon activation of GSK-3 ß.

Differential expression and androgen regulation of microRNAs and metalloprotease 13 in breast cancer cells.

MicroRNA molecules (miRNAs) play important roles in regulating cell behavior. The expression of certain miRNAs has been shown to be regulated by the androgen receptor (AR), which seems to have a critical role in the tumorigenic process of breast cancer. The differential expression of 84 miRNAs was first examined in three breast cancer cell lines: the luminal MCF-7 and T47D cells and the molecular apocrine MDA-MB-453 cells. Analysis of basal expression of miRNAs revealed that each cell line had distinct miRNA expression where let-7a and -7b were markers of MDA-MB-453 cells, whereas miR-205 was a marker for the luminal cell lines. Treating the cells with the AR agonist, CI-4AS-1, resulted in unique alterations in the expression of specific miRNA among the three cell lines. Particularly, the expression of miR-100 and miR-125 was reduced in MDA-MB-453 cells by five and three folds, respectively. This effect was simultaneous with AR-induced increase in the expression and extracellular release of metalloprotease-13 (MMP13). Transfection of cells with either miR-100 or miR-125b negated the induction of MMP13 release. Additionally, AR activation induced a morphological alteration of MDA-MB-453 cells, which was blocked by miR-125b only. Collectively, these data indicate that AR may control the biological behavior of breast cancer cells and protein expression via miRNAs.

Vacuolar ATPase driven potassium transport in highly metastatic breast cancer cells.

Breast cancer is the second leading cause of death in women and thus has received a great deal of attention by researchers. Recent studies suggested decreased occurrence of cancer in patients treated with cardiac glycosides (CGs) for heart conditions. Because CGs induce their cellular effects via the Na(+), K(+) ATPase (Na-K), we treated four breast cancer cell lines (MCF-7, T47D, MDA-MB453, and MDA-MB231) and a non-cancerous breast ductal epithelial cell line (MCF-10A) with ouabain, a well-characterized CG, and measured cell proliferation by measuring bromodeoxyuridine incorporation. Ouabain (1µM) decreased cell proliferation in all cell lines studied except MDA-MB453 cells. Western blot of Na-K α and ß subunits showed α1, α3, and ß1 expression in all cell lines except MDA-MB453 cells where Na-K protein and mRNA were absent. Potassium uptake, measured as rubidium ((86)Rb) flux, and intracellular potassium were both significantly higher in MDA-MB453 cells compared to MCF-10A cells. RT-qPCR suggested a 7 fold increase in voltage-gated potassium channel (KCNQ2) expression in MDA-MB453 cells compared to MCF-10A cells. Inhibition of KCNQ2 prevented cell growth and (86)Rb uptake in MDA-MB453 cells but not in MCF-10A cells. All cancer cells had significantly higher vacuolar H-ATPase (V-ATPase) activity than MCF-10A cells. Inhibition of V-ATPase decreased (86)Rb uptake and intracellular potassium in MDA-MB453 cells but not in MCF-10A cells. The findings point to the absence of Na-K, high hERG and KCNQ2 expression, elevated V-ATPase activity and sensitivity to V-ATPase inhibitors in MDA-MB453. We conclude that cancer cells exhibit fundamentally different metabolic pathways for maintenance of intracellular ion homeostasis.

Effects of hirsuteine on MDA-MB-453 breast cancer cell proliferation.

Hirsuteine is extracted from Uncaria rhynchophylla, the bark of which has traditionally been used to treat hypertension, cancer, convulsions, hemorrhage, auto-immune disorders, and other ailments. The anticancer properties of hirsuteine are of significant importance to the research community; however, its underlying mechanism of action is not well understood. The aim of the present study was to examine the antiproliferative ability of hirsuteine using human breast cancer MDA-MB-453 cells and to determine the underlying molecular mechanism involved in its therapeutic efficacy. The effects of hirsuteine on cell viability were determined using CCK-8 and colony formation assays, while apoptosis was assessed using flow cytometry. Cell cycle distribution was assessed using flow cytometry, and apoptotic cell quantification was performed using via Annexin V-FITC/PI staining and flow cytometry. Reverse transcription-quantitative PCR and western blotting were used to assess the expression of cell cycle progression and apoptosis associated genes and proteins. MDA-MB-453 cell proliferation was significantly reduced by hirsuteine in a concentration and time-dependent manner. Hirsuteine-treated cells exhibited G2/M phase arrest, as evidenced by the increase in G2/M phase cells and a decrease in the G0/G1 phase cells, and this was related to cyclin B1 and CDK1 downregulation. Furthermore, hirsuteine accelerated MDA-MB-453 cell apoptosis by downregulating Bcl-2 while upregulating cytoplasmic cytochrome c, Bax, Apaf1, cleaved caspase-3, and cleaved caspase-9 levels, which together drove apoptotic cell death. Thus, hirsuteine suppressed MDA-MB-453 cancer cell proliferation by inducing cell cycle arrest and promoting apoptosis.

Data on 2D culture characterisation of potential markers in human HER2-positive breast cancer cell lines.

To obtain this dataset, two human HER2-positive breast cancer cell lines (SKBR3 and MDA-MB-453 cell lines) were cultured in basal growth media to 80% confluence. Cells were passaged and total RNA extracted, RNA converted to cDNA and diluted to a working concentration of 40 ng/µL. Gene expression panels of cancer markers including Fibroblast growth factors (FGF), FGF receptors (FGFRs), cyclin-dependent kinases, cytokeratins, and WNT pathway components were then examined using Q-PCR. Gene expression was normalised against the expression of the endogenous gene 18S. This article describes the data used in the research article "Syndecan-4 regulates the HER2-positive breast cancer cell proliferation cells via CK19/AKT signaling" [1]. The data presented demonstrates the range of gene expression profiles of these cells and aims to provide more detail of all gene expression changes observed in these cell lines.

Synergistic actions of Alpelisib and Melatonin in breast cancer cell lines with PIK3CA gene mutation.

AIMS: Breast cancer (BC) presents high mortality rate and about 25-46 % have mutation in the PIK3CA gene. Alpelisib is a PI3K inhibitor that acts on p110α, which is a subunit of the PI3K protein. The melatonin shown important anti-neoplastic effects and may increase the effectiveness of chemotherapy. This study evaluated the synergistic action of Alpelisib and Melatonin in BC lines carrying the H1047R mutation in PIK3CA, relative to the cellular dynamics and the PI3K/AKT/mTOR pathway. MAIN METHODS: MDA-MB-468 (triple-ernegative), MDA-MB-453 (H1047R PIK3CA, HER2+) and T-47D cells (H1047R PIK3CA, ER+/PR+) were divided into four treatment groups: control; Melatonin (1 mM); Alpelisib (1 µM); and Alpelisib (1 µM) + Melatonin (1 mM). Cell viability and migration were investigated using the MTT assay and Transwell assay, respectively. Protein expression of PI3K, p-AKT, mTOR, HIF-1α, and caspase-3, was verified using immunocytochemistry. KEY FINDINGS: MTT assay revealed that MDA-MB-453 and T-47D showed reduction in cell viability in all groups, especially in the MDA-MB-453 treated with Melatonin + Alpelisib. MDA-MB-468 presents reduction in cell migration only with Melatonin, while in the lines with mutation, the treatment of Melatonin + Alpelisib caused inhibition of cell migration. PI3K, p-AKT, mTOR and HIF-1α were inhibited after treatment with Melatonin + Alpelisib in MDA-MB-453 and T-47D lines. The expression of caspase-3 increased in all groups in MDA-MB-453 and T-47D cells, being the increase more pronounced in the Melatonin + Alpelisib group. SIGNIFICANCE: These results indicate that the combined use of Melatonin and Alpelisib may be more effective in inhibiting BC in women carrying the PIK3CA gene mutation than either treatment alone.

Syndecan-4 regulates the HER2-positive breast cancer cell proliferation cells via CK19/AKT signalling.

Despite the use of the highly specific anti-HER2 receptor (trastuzumab) therapy, HER2-positive breast cancers account for 20-30% of all breast cancer carcinomas, with HER2 status a challenge to treatment interventions. The heparan sulfate proteoglycans (HSPGs) are prominently expressed in the extracellular matrix (ECM), mediate breast cancer proliferation, development, and metastasis with most studies to date conducted in animal models. This study examined HSPGs in HER2-positive human breast cancer cell lines and their contribution to cancer cell proliferation. The study examined the cells following enhancement (via the addition of heparin) and knockdown (KD; using short interfering RNA, siRNA) of HSPG core proteins. The interaction of HSPG core proteins and AKT signalling molecules was examined to identify any influence of this signalling pathway on cancer cell proliferation. Our findings illustrated the HSPG syndecan-4 (SDC4) core protein significantly regulates cell proliferation with increased BC cell proliferation following heparin addition to cultures and decreased cell number following SDC4 KD. In addition, along with SDC4, significant changes in CK19/AKT signalling were identified as mediators of BC HER2-positive BC cell proliferation. This study provides evidence for a cell growth regulatory axis involving HSPGs/CK19 and AKT that represents a potential molecular target to prevent proliferation of HER2-positive breast cancer cells.

Androgen downregulates desmocollin-2 in association with induction of mesenchymal transition of breast MDA-MB-453 cancer cells.

Desmosomes are cellular structures that are critical in cell-cell adhesion and in maintaining tissue architecture. Changes in the expression of desmocollin-2 (DSC2) have been noted during tumor progression into an invasive phenotype and as cells undergo epithelial-mesenchymal transition. We have previously reported that breast MDA-MB-453 cancer cells, a luminal androgen receptor (AR) model of triple-negative breast cancer, acquire mesenchymal features when treated with the AR agonist, dihydrotestosterone (DHT). We have therefore investigated androgen regulation of the expression and cellular localization of DSC2 in MDA-MB-453 cells. Treatment of the cells with DHT resulted in a dose-dependent reduction in DSC2 protein levels and dispersion of its membrane localization concomitant with AR- and ß-catenin-mediated mesenchymal transition of cells. A significant correlation was revealed between decreased expression of AR and increased expression of DSC2 in patient samples. In addition, whereas lower expression of AR was associated with a reduced overall and recurrence-free survival of breast cancer patients, higher expression of DSC2 was found in invasive breast tumors than in normal breast cells and was correlated with lower patient survival. Upon knocking down DSC2, the cells became elongated, mesenchymal-like, and slightly, but insignificantly, more migratory. The addition of DHT further stimulated cell elongation and migration. DSC2 siRNA-transfected cells reverted to a normal epithelial morphology upon inhibition of ß-catenin. These results highlight the role of DSC2 in maintaining the epithelial morphology of MDA-MB-453 cells and the negative regulation of the desmosomal protein by DHT during stimulation of the androgen-induced, ß-catenin-mediated mesenchymal transition of the cells.

MFUM-BrTNBC-1, a Newly Established Patient-Derived Triple-Negative Breast Cancer Cell Line: Molecular Characterisation, Genetic Stability, and Comprehensive Comparison with Commercial Breast Cancer Cell Lines.

Triple-negative breast cancer (TNBC) is a breast cancer (BC) subtype that accounts for approximately 15-20% of all BC cases. Cancer cell lines (CLs) provide an efficient way to model the disease. We have recently isolated a patient-derived triple-negative BC CL MFUM-BrTNBC-1 and performed a detailed morphological and molecular characterisation and a comprehensive comparison with three commercial BC CLs (MCF-7, MDA-MB-231, MDA-MB-453). Light and fluorescence microscopy were used for morphological studies; immunocytochemical staining for hormone receptor, p53 and Ki67 status; RNA sequencing, qRT-PCR and STR analysis for molecular characterisation; and biomedical image analysis for comparative phenotypical analysis. The patient tissue-derived MFUM-BrTNBC-1 maintained the primary triple-negative receptor status. STR analysis showed a stable and unique STR profile up to the 6th passage. MFUM-BrTNBC-1 expressed EMT transition markers and displayed changes in several cancer-related pathways (MAPK, Wnt and PI3K signalling; nucleotide excision repair; and SWI/SNF chromatin remodelling). Morphologically, MFUM-BrTNBC-1 differed from the commercial TNBC CL MDA-MB-231. The advantages of MFUM-BrTNBC-1 are its isolation from a primary tumour, rather than a metastatic site; good growth characteristics; phenotype identical to primary tissue; complete records of origin; a unique identifier; complete, unique STR profile; quantifiable morphological properties; and genetic stability up to (at least) the 6th passage.

Antitumor potential of dark sweet cherry sweet (Prunus avium) phenolics in suppressing xenograft tumor growth of MDA-MB-453 breast cancer cells.

This study investigated in vivo the antitumor activity of dark sweet cherry (DSC) whole extracted phenolics (WE) and fractions enriched in anthocyanins (ACN) or proanthocyanidins (PCA) in athymic mice xenografted with MDA-MB-453 breast cancer cells. Mice were gavaged with WE, ACN or PCA extracts (150 mg/kg body weight/day) for 36 days. Results showed that tumor growth was suppressed at similar levels by WE, ACN and PCA compared to control group (C) without signs of toxicity or significant changes in mRNA oncogenic biomarkers in tumors or mRNA invasive biomarker in distant organs. Tumor protein analyses showed that WE, ACN and PCA induced at similar levels the stress-regulated ERK1/2 phosphorylation, known to be linked to apoptosis induction. However, ACN showed enhanced antitumor activity through down-regulation of total oncogenic and stress-related Akt, STAT3, p38, JNK and NF-kB proteins. In addition, immunohistochemistry analysis of Ki-67 revealed inhibition of tumor cell proliferation with potency WE ≥ ACN ≥ PCA. Differential quantitative proteomic high-resolution nano-HPLC tandem mass spectrometry analysis of tumors from ACN and C groups revealed the identity of 66 proteins associated with poor breast cancer prognosis that were expressed only in C group (61 proteins) or differentially up-regulated (P<.05) in C group (5 proteins). These findings revealed ACN-targeted proteins associated to tumor growth and invasion and the potential of DSC ACN for breast cancer treatment. Results lead to a follow-up study with highly immunodeficient mice/invasive cell line subtype and advanced tumor development to validate the anti-invasive activity of DSC anthocyanins.

Synthesis and Characterization of Folic Acid Conjugated Gemcitabine Tethered Silver Nanoparticles (FA-GEM-AgNPs) for Targeted Delivery.

BACKGROUND: Silver nanoparticles (AgNPs) have attracted considerable interest in the medical industry due to their physicochemical properties, small size, and surface plasmon behavior. Their smaller particle size and instability in blood circulation leads to toxicity due to its aggregation as Ag+ ions and accumulation at the deepseated organ. In the present study, we aimed at reducing the toxicity of AgNPs by conjugation with an anticancer drug GEM and to improve their internalization through folate receptors-mediated endocytosis by capping the nanoparticles with folic acid (FA). METHODS: One-pot facile synthesis of FA capped silver nanoparticles (FA-AgNPs) has been achieved by using FA as a reducing agent. FA-AgNPs were mixed with Gemcitabine (GEM) to obtain tethered FA-GEM-AgNPs. Nanoparticles were characterized by Dynamic Light Scattering (DLS), UV-Visible spectroscopy, Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Analysis (EDAX), Selected Area Electron Diffraction (SAED), and Atomic Absorption Spectroscopy (AAS). The 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was carried out to determine the cytotoxic effect of the prepared nanoformulations. The apoptotic cell death induced by FA-GEM-AgNPs in breast cancer cells were monitored with Acridine orange (AO)/Ethidium Bromide (EtBr) staining. CONCLUSION: Compared to GEM and AgNPs, FA-GEM-AgNPs showed enhanced cytotoxic effect and internalization in MDA-MB-453 breast cancer cell line. FA-GEM-AgNPs could be an ideal candidate for targeting cancer cells via folate receptor-mediated endocytosis.

Apigenin Induces Apoptosis through a Mitochondria/Caspase-Pathway in Human Breast Cancer MDA-MB-453 Cells.

In this study, we investigated the mechanistic role of the caspase cascade in extrinsic and intrinsic apoptosis induced by apigenin, which has been targeted as a candidate in the development of noncytotoxic anticancer medicines. Treatment with apigenin (1-100 microM) significantly inhibited the proliferation of MDA-MB-453 human breast cancer cells in a dose- and time-dependent manner with IC(50) values of 59.44 and 35.15 microM at 24 and 72 h, respectively. This inhibition resulted in the induction of apoptosis and the release of cytochrome c in cells exposed to apigenin at its 72 h IC(50). Subsequently, caspase-9, which acts in mitochondria-mediated apoptosis, was cleaved by apigenin. In addition, apigenin activated caspase-3, which functions downstream of caspase-9. The apigenin-induced activation of caspase-3 was accompanied by the cleavage of capases-6, -7, and -8. These results are supported by evidence showing that the activity patterns of caspases-3, -8, and -9 were similar. The present study supports the hypothesis that apigenin-induced apoptosis involves the activation of both the intrinsic and extrinsic apoptotic pathways.

Luteolin exhibits anti-breast cancer property through up-regulating miR-203.

Luteolin is a representative of natural flavonoid that has anti-tumour properties. This study designed to check its impact on breast cancer and the underlying mechanisms. MDA-MB-453 and MCF-7 cells were administrated with luteolin and the following techniques were carried out: CCK-8 assay, FITC-PI double-staining and Western blot. qRT-PCR analysis was utilized to see the effects of luteolin on miR-203 expression. Besides, miR-203 expression was silenced by transfection with specific inhibitor. Luteolin remarkably declined MDA-MB-453 and MCF-7 cells viability and accelerated apoptosis which accompanied by Bax up-regulation, Bcl-2 down-regulation and Caspase-3 cleavage. Also, luteolin impeded TGFß1-induced EMT, as evidenced by the decreased levels of Vimentin, Zeb1 and N-cadherin, as well as the increased level of E-cadherin. miR-203 was highly expressed in 22 pair of breast cancer tissues than the matched paracancerous tissues. Luteolin could elevate miR-203 level. Besides, luteolin's anti-tumour effects were partially eliminated by miR-203 silence. Further, luteolin inhibited Ras/Raf/MEK/ERK signalling, while the inhibitory effects were flattened by miR-203 silence. Luteolin significantly reduced breast cancer cells growth and EMT. Luteolin exerted its anti-tumour effects possibly involved the elevated expression of miR-203 and the inhibited Ras/Raf/MEK/ERK signalling.

A diverse induction of apoptosis by trabectedin in MCF-7 (HER2-/ER+) and MDA-MB-453 (HER2+/ER-) breast cancer cells.

Trabectedin (Yondelis, ET-743), a semi synthetic tetrahydroisoquinoline alkaloid that was originally derived from the marine tunicate Ecteinascidia turbinata. The objective of this study was to investigate whether trabectedin mediated apoptosis shows any diversity in human breast cancer cell lines with different genotypes. Trabectedin induced cytotoxicity and apoptosis in both breast cancer cells in a time and concentration-dependent manner. The expression levels of the death receptor pathway molecules, TRAIL-R1/DR4, TRAIL-R2/DR5, FAS/TNFRSF6, TNF RI/TNFRSF1A, and FADD were significantly increased by 2.6-, 3.1-, 1.7-, 11.2- and 4.0-fold by trabectedin treatment in MCF-7 cells. However, in MDA-MB-453 cells, the mitochondrial pathway related pro-apoptotic proteins Bax, Bad, Cytochrome c, Smac/DIABLO, and Cleaved Caspase-3 expressions were induced by 4.2-, 3.6-, 4.8-, 4.5-, and 4.4-fold, and the expression levels of anti-apoptotic proteins Bcl-2 and Bcl-XL were reduced by 4.8- and 5.2-fold in MDA-MB-453 cells. Moreover, trabectedin treatment increased the generation of ROS in both breast cancer cells. We have shown that trabectedin causes selective activation of extrinsic and intrinsic apoptotic pathways in two genotypically different breast cancer cells. This preliminary data might guide clinicians to choose appropriate combination agents with trabectedin based on different molecular subtypes of breast cancer.

Kaempferol induced the apoptosis via cell cycle arrest in human breast cancer MDA-MB-453 cells.

The aim of present study was to investigate the effects of kaempferol on cellular proliferation and cell cycle arrest and explore the mechanism for these effects in human breast carcinoma MDA-MB-453 cells. Cells were treated with kaempferol at various concentrations (ranging from 1 to 200 microM) for 24 and 48 hrs. Kaempferol significantly inhibited cancer cell growth in cells exposed to 50 and 10 microM of kaempferol and incubated for 24 and 48 hrs, respectively. Exposure to kaempferol resulted in cell cycle arrest at the G2/M phase. Of the G2/M-phase related proteins, kaempferol down-regulated CDK1 and cyclin A and B in cells exposed to kaempferol. In addition, small DNA fragments at the sub-G0 phase were increased by up to 23.12 and 31.90% at 10 and 50 microM incubated for 24 and 48 hrs, respectively. The kaempferol-induced apoptosis was associated with the up-regulation of p53. In addition, the phosphorylation of p53 at the Ser-15 residue was observed with kaempferol. Kaempferol inhibits cell proliferation by disrupting the cell cycle, which is strongly associated with the induction of arrest at G2/M phase and may induce apoptosis via p53 phosphorylation in human breast carcinoma MDA-MB-453 cells.