mtt-formazan and Breast-Neoplasms

A novel heterometallic metal-porphyrinic framework (MPFs) built from Y and K ions as nods and meso-tetra(4-carboxyphenyl)porphyrin as linkers has been successfully synthesized and characterized. The single crystal X-ray diffraction indicated that this complex 1 exhibited a bilayered architecture of the porphyrins, which is seldom seen in MPFs. In addition, in vitro anticancer activity of complex 1 on three human breast cancer cells (BT474, SKBr-3 and ZR-75-30) was further determined.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Coordination Complexes; Crystallography, X-Ray; Formazans; Humans; Hydrogen Bonding; Metal-Organic Frameworks; Molecular Structure; Porphyrins; Reference Values; Reproducibility of Results; Tetrazolium Salts

To investigate the role of microRNAs in doxorubicin resistance of breast cancer cells.. MicroRNA-134 was down-regulated in doxorubicin-resistant and doxorubicin-sensitive breast cancer samples and MCF-7/ADR cell lines. After transfection of miR-134 mimics, an MTT assay confirmed that the MCF-7/ADR cell proliferation was inhibited. In the presence of doxorubicin, there was inhibition of cell proliferation. Transfection of miR-134 mimics induced MCF-7/ADR cell apoptosis. The expression of ABCC1 was significantly upregulated in doxorubicin-resistant or -sensitive breast cancer tissues and MCF-7/ADR cell lines. Over-expression of miR-134 decreased the expression of ABCC1 at the protein level.. MicroRNA-134 modulates resistance to doxorubicin in breast cancer cells by downregulating the expression of ABCC1 which is known to encode the multidrug resistance-associated protein 1.

Topics: Antibiotics, Antineoplastic; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Down-Regulation; Doxorubicin; Drug Resistance, Neoplasm; Formazans; Humans; MicroRNAs; Models, Biological; Multidrug Resistance-Associated Proteins; Tetrazolium Salts

The WHI trial suggests an increase of breast cancer in postmenopausal women probably according to the progestogenic compound, i.e. medroxyprogesterone acetate (MPA). However, the mechanism for a possible carcinogenic effect of MPA remains unclear so far. Progesterone receptor membrane component-1 (PGRMC1) may be important in tumorigenesis and thus may increase breast cancer risk. We investigated the influence of MPA alone and in combination with growth factors on breast cancer cells overexpressing PGRMC1.. MCF-7 cells were stably transfected with PGRMC1 expression plasmid (WT-12 cells). Cells transfected only with the vector were used as control cells (EVC-cells). Medroxyprogesterone acetate (MPA), norethisterone (NET) and progesterone (P) were tested alone and in combination with a mixture of growth factors. Cell proliferation was measured by MTT assay.. The growth factor mixture (GF) was able to induce cell proliferation in both cell types, however, the effect was much higher in the WT-12 cells. In WT-12 cells both MPA and NET alone significantly increased cell proliferation with values of 40% and 97%, respectively. Progesterone, however, had no effect. In combination with GF MPA significantly further enhanced cell proliferation as compared to the effect of MPA alone and GF alone in both cell lines. NET showed no further increase as compared to NET alone and P had no effect.. We could demonstrate a significant proliferative effect of MPA when combined with high concentrations of growth factors. This effect was more pronounced in breast cancer cells overexpressing PGRMC1. These results may be of clinical relevance since in the combined WHI trial an increased breast cancer risk was found during treatment with conjugated equine estrogens plus MPA.

Topics: Breast Neoplasms; Cell Proliferation; Female; Formazans; Humans; Intercellular Signaling Peptides and Proteins; MCF-7 Cells; Medroxyprogesterone Acetate; Membrane Proteins; Norethindrone; Progesterone; Receptor Cross-Talk; Receptors, Progesterone; Tetrazolium Salts

The purpose of study was to examine the cytotoxic and anti-cancer properties along with addressing the plausible pathway followed by scorpion venom to reduce cell viability in SH-SY5Y and MCF-7 cells. Following exposure of cells with scorpion venom, cytotoxicity was estimated using MTT and lactate dehydrogenase assays. Apoptotic effects were measured by assessment of mitochondrial membrane potential, reactive nitrogen species, DNA fragmentation, and caspase-3 activity whereas antiproliferative effect was assayed using BrdU incorporation. Our results indicate that scorpion venom causes suppression of proliferation by arresting S-phase and induction of apoptosis through increased nitric oxide production, caspase-3 activity and depolarization of mitochondrial membrane. Induction of apoptosis and arrest of DNA synthesis are critical determinant factors for development of anti cancer drugs. These properties may lead to isolation of effective molecule(s) with potential anticancer activity from scorpion venom of Androctonus crassicauda.

Topics: Animals; Apoptosis; Breast Neoplasms; Bromodeoxyuridine; Cell Cycle; Cell Line, Transformed; Cell Line, Tumor; Cell Proliferation; Cell Survival; DNA Fragmentation; DNA Replication; Female; Formazans; Humans; Lactate Dehydrogenases; Membrane Potential, Mitochondrial; Neuroblastoma; Nitric Oxide; Scorpion Venoms; Tetrazolium Salts; Tumor Stem Cell Assay

The characterization and quantification of extra-virgin olive oil (EVOO) phenolic compounds by a rapid resolution liquid chromatography (RRLC) method coupled to diode-array and time of flight mass spectrometry (TOF) detection systems was developed. The RRLC method transferred from a conventional HPLC one achieved better performance with shorter analysis times. The phenolic compounds were separated with a C18 column (150 mm x 4.6mm, 1.8 microm) using water with 0.5% acetic acid and acetonitrile as mobile phases. Good peak resolution was obtained and 19 different phenols were identified in less than 20 min providing a new level of information about the samples in shorter time. The applicability of this analytical approach was confirmed by the successful analysis of three different EVOO varieties (Picual, Hojiblanca, and Arbequina) obtained from different trademarks. Besides identification of the most important phenolic compounds and their quantification in three different ways (RRLC-UV, RRLC-MS and a new approach using the total polyphenol content obtained with Folin Ciocalteau, the relative areas and the response factors), we also described the occurrence of correlations between the phenolic composition of EVOO-derived crude phenolic extracts and their anti-proliferative abilities toward human breast cancer-derived cell lines. When compared with lignans-rich EVOO varieties, secoiridoids-rich EVOO had a significantly strong ability to alter cell viability in four different types of human breast carcinoma cells.

Topics: Antineoplastic Agents; Breast Neoplasms; Calibration; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chromatography, Liquid; Dose-Response Relationship, Drug; Female; Formazans; Humans; Mass Spectrometry; Olive Oil; Phenols; Plant Oils; Reference Standards; Spectrometry, Mass, Electrospray Ionization; Tetrazolium Salts; Time Factors

Two new complexes [(Etdpa)MnCl(2)] and [(Adpa)Mn(Cl)(H(2)O)] (Etdpa = ethyl bis(2-pyridylmethyl)amino-2-propionate; Adpa = bis(2-pyridylmethyl)amino-2-propionic acid) were synthesized and characterized by spectral methods. The crystal structure of [(Etdpa)MnCl(2)] shows that the Mn(II) atom is coordinated by three N atoms (N1, N2, N3), one oxygen atom (O1) of the ligand (Etdpa) and two chloride atoms (Cl1, Cl2), forming a distorted octahedral geometry. The binding interaction between ct-DNA and the synthesized complexes was relatively weak, but they can inhibit the induced swelling of Ca(2+)-loaded mitochondria in a dose-dependent manner. The [(Adpa)Mn(Cl)(H(2)O)] can cause the obvious decrease of mitochondria membrane potential. The MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenpyltetra-zolium bromide) assay shows that the two Mn(II) complexes are more active against cancer cells. Especially [(Adpa)Mn(Cl)(H(2)O)] can inhibit the proliferation of glioma cells with IC(50) 9.5 μM. Experimental results indicate that the [(Adpa)Mn(Cl)(H(2)O)] could be a new potential antitumor complex to target the mitochondria.

Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Coordination Complexes; DNA; Drug Evaluation, Preclinical; Drug Interactions; Esophageal Neoplasms; Female; Formazans; Glioma; HeLa Cells; Humans; Inhibitory Concentration 50; Manganese; Membrane Potential, Mitochondrial; Mitochondria, Liver; Molecular Structure; Oxygen; Rats; Reference Standards; Tetrazolium Salts

Interplay between integrins and extracellular matrix is suggested to play an important role in malignant progression and tumor differentiation. The aim of the study was to determine the combined expression of integrin β3 and tenascin-c (TN-c) in breast cancer and examine whether integrin β3 and TN-c can activate urokinase-type plasminogen activator (uPA) through p38 mitogen-activated protein kinase (p38 MAPK). We detected the expression of integrin β3, TN-c, p-p38, and uPA in 80 cases of breast invasive ductal carcinoma by immunohistochemistry. In addition, we blocked integrin β3 and TN-c in the MDA-MB-231 breast cancer cells and detected the expression of p-p38 and uPA by Western blot. Integrin β3, TN-c, p-p38, and uPA showed high levels of expression in breast invasive ductal carcinoma. The expression of integrin β3, TN-c, and uPA was correlated with lymph node metastasis and TNM stage in breast cancer. Furthermore, correlations were noted between any two of the three proteins. The expression of p-p38 and uPA decreased in MDA-MB-231 cells after the addition of integrin β3 antibody and TN-c antibody. The expression of uPA decreased after addition of SB203580. Our results demonstrate that inhibition of the expression of integrin β3 and TN-c could decrease the expression of uPA through p38 MAPK in breast cancer, suggesting that the interaction between integrin β3 and TN-c serves an important role in breast cancer.

Topics: Adult; Aged; Breast Neoplasms; Carcinoma, Ductal, Breast; Cell Line, Tumor; Cell Survival; Chi-Square Distribution; Enzyme Inhibitors; Female; Formazans; Humans; Imidazoles; Immunohistochemistry; Integrin beta3; Middle Aged; p38 Mitogen-Activated Protein Kinases; Pyridines; Retrospective Studies; Tenascin; Tetrazolium Salts; Urokinase-Type Plasminogen Activator

The aims of this study were to find the electroactive species in the human breast cancer (MCF-7) cell cytoplasm causing a voltammetric response of the cells and to establish a simple and rapid measurement method to obtain strong and direct electrochemical responses objectively reflecting the cell viability. Ultrasonication was carried out for the electrochemical detection. The presence of guanine and xanthine in the MCF-7 cell eluent secreted by the living cells and in the MCF-7 cell cytoplasm was verified by HPLC assay with a DAD system and chemometric method. The concentrations of guanine and xanthine in the MCF-7 cell cytoplasm and the voltammetric response of the MCF-7 cell cytoplasm had higher levels than those of intact cell suspensions. Additionally, taxol caused a decrease of the voltammetric response of the cytoplasm and concentrations of xanthine and guanine in the cytoplasm. Therefore, the origin of the voltammetric response of the MCF-7 cytoplasm was driven by the alteration of the levels of xanthine and guanine, which were related to the cell viability. Thus, the voltammetric response of the ultrasonicated MCF-7 cell suspension could be used to monitor the MCF-7 cell growth and to evaluate the effectiveness of antitumor drugs on tumor suppression.

Topics: Antineoplastic Agents, Phytogenic; Breast Neoplasms; Carbon; Cell Culture Techniques; Cell Line, Tumor; Cell Survival; Chromatography, High Pressure Liquid; Cytoplasm; Electrochemistry; Electrodes; Female; Formazans; Guanine; Humans; Models, Biological; Oxidation-Reduction; Paclitaxel; Tetrazolium Salts; Time Factors; Ultrasonics; Xanthine

The effects of the alpha-diketone derivatives 2,3- and 3,4-hexanediones were investigated in three non-neuronal cell lines (MCF7, HepG(2) and CaCo-2) as well as in the neuroblastoma line, SH-SY5Y. The MTT reduction assay was employed to determine the necrotic effects of the alpha-diketones and the neurotoxin 2,5-hexanedione over 4, 24 and 48 hr exposures. Flow cytometry was also used to study the effects of the three isomers on the cell cycle of the SH-SY5Y line only. With 2,5-hexanedione, the mean MTT IC(50) decreased more than 10-fold from 4 to 48 hr. The toxicities of both alpha-diketones were similar, with a more than 18-fold increase in sensitivity of the SH-SY5Y at 24 hr compared to that of 4 hr. With flow cytometry at 48 hr, SH-SY5Y apoptosis with 2,5-hexanedione rose throughout the concentration range evaluated (0-30 mM) while 2,3- and 3,4-hexanediones showed apoptosis over the concentration range 1-1.6 mM, with 3,4-hexanedione being the more potent compared to the 2,3-isomer. At 1.6 mM nearly all the cells had entered apoptosis in the presence of the 3,4-isomer, (94.9 +/- 1.4%) but only 57.5 +/- 4.1% of the 2,3-isomer-treated cells had reached that stage. The 2,3- and 3,4-isomers in diets alone may not pose a serious threat to human health. Further studies may be necessary to evaluate the effects of other dietary components on their toxicity. These alpha-diketones also display a degree of toxic selectivity towards neuroblastoma cells, which may have therapeutic implications.

Topics: Adenocarcinoma; Apoptosis; Breast Neoplasms; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Flow Cytometry; Formazans; Hexanones; Humans; Isomerism; Neuroblastoma; Neurons; Tetrazolium Salts

Polypyrrole-Fe3O4 nanospheres were synthesized via an emulsion polymerization method with hyaluronic acid as the surfactant. Hyaluronic acid offers the advantages of biocompatibility, cell adhesive property and the availability of functional groups for attachment of other molecules. The nanospheres were further functionalized with herceptin, and the efficacy of uptake of the functionalized nanospheres by human breast cancer cells was evaluated. It is envisioned that the combination of hyaluronic acid with its cell adhesive property and herceptin would result in high efficacy of internalization of the nanospheres by the cancer cells via a HER-2-mediated endocytosis. Our results showed that this is indeed the case and that the high concentration of herceptin-functionalized magnetic nanospheres in the cancer cells offers great potential in cancer cell targeting and treatment. In addition, the magnetic property of these nanospheres was also critically investigated and the magnetization was found to be affected by the particles' environment. The combination of these cell-targeting magnetic carriers with chemotherapeutic agents will be highly advantageous for the preferential killing of cancer cells in hyperthermia treatment.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Endocytosis; Female; Formazans; Genetic Therapy; Humans; Light; Magnetics; Nanospheres; Particle Size; Receptor, ErbB-2; Scattering, Radiation; Tetrazolium Salts; Trastuzumab

To investigate whether subtoxic concentration of beta-sitosterol (SITO) combined with TNF-related apoptosis-inducing ligand (TRAIL) induces apoptosis in TRAIL-resistant MDA-MB-231 breast cancer cells.. Cell viability and growth were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphnyl-2H-tetrazolim bromide assays, chromatin condensation, release of lactate dehydrogenase (LDH), and Annexin V+ cells. The apoptosis-related proteins were detected by Western blotting.. Treatment with TRAIL in combination with subtoxic concentrations of SITO sensitized MDA-MB-231 breast cancer cells to TRAIL-mediated apoptosis. The synergistic treatment induced chromatin condensation, DNA fragmentation, the release of LDH, and Annexin V+ cells. The indicators of apoptosis are correlated to the induction of caspase activities, which results in the cleavage of poly(ADP-ribose)polymerase. Both the cytotoxic effects and apoptotic characteristics induced by the synergistic treatment were significantly inhibited by a pan-caspase inhibitor z-VAD-fmk, demonstrating the important role of caspases. These results indicate that caspases are crucial regulators of apoptosis induced by the combined treatment of SITO and TRAIL in MDA-MB-231 cells.. The synergistic treatment of SITO and TRAIL induces apoptosis, which can serve as a potential preventive and therapeutic agent.

Topics: Annexin A5; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Drug Synergism; Female; Fluorescein-5-isothiocyanate; Fluorescent Dyes; Formazans; Humans; Hypolipidemic Agents; Sitosterols; Tetrazolium Salts; TNF-Related Apoptosis-Inducing Ligand

Recently, we have introduced [tris(1,10-phenanthroline)lanthanum(III)] trithiocyanate (KP772, FFC24) as a new lanthanum compound which has promising anticancer properties in vivo and in vitro. Aim of this study was to investigate the impact of ABC transporter-mediated multidrug resistance (MDR) on the anticancer activity of KP772. Here, we demonstrate that all MDR cell models investigated, overexpressing ABCB1 (P-glycoprotein), ABCC1 (multidrug resistance protein 1), or ABCG2 (breast cancer resistance protein) either due to drug selection or gene transfection, were significantly hypersensitive against KP772. Using ABCB1-overexpressing KBC-1 cells as MDR model, KP772 hypersensitivity was demonstrated to be based on stronger apoptosis induction and/or cell cycle arrest at unaltered cellular drug accumulation. KP772 did neither stimulate ABCB1 ATPase activity nor alter rhodamine 123 accumulation arguing against a direct interaction with ABCB1. Accordingly, several drug resistance modulators did not sensitize but rather protect MDR cells against KP772-induced cytotoxicity. Moreover, long-term KP772 treatment of KBC-1 cells at subtoxic concentrations led within 20 passages to a complete loss of drug resistance based on blocked MDR1 gene expression. When exposing parental KB-3-1 cells to subtoxic, stepwise increasing KP772 concentrations, we observed, in contrast to several other metallo-drugs, no acquisition of KP772 resistance. Summarizing, our data demonstrate that KP772 is hyperactive in MDR cells and might have chemosensitizing properties by blocking ABCB1 expression. Together with the disability of tumor cells to acquire KP772 resistance, our data suggest that KP772 should be especially active against notoriously drug-resistant tumor types and as second line treatment after standard chemotherapy failure.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters; Breast Neoplasms; Carcinoma, Small Cell; Cell Cycle; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Resistance, Multiple; Drug Resistance, Neoplasm; Formazans; HL-60 Cells; Humans; Lanthanum; Lung Neoplasms; Molecular Structure; Neoplasm Proteins; Organic Anion Transporters; Organometallic Compounds; Phenanthrolines; Sensitivity and Specificity; Tetrazolium Salts

Therapies including nucleoside analogs are associated with severe toxic side effects and acquirement of drug resistance. We have previously reported the drug delivery in the form of 5'-triphosphates (NTP) encapsulated in cross-linked cationic networks of polyethylenimine (PEI) and PEG/Pluronic polymers (Nanogels). In this study, Nanogels, containing biodegradable PEI that could easily dissociate in reducing cytosolic environment and form products with minimal toxicity, were synthesized and displayed low cytotoxicity. Toxicity of Nanogels was clearly dependent on the total positive charge of carriers and was 5-6 fold lower for carriers loaded with NTP. Though intracellular ATP level was immediately reduced by ca. 50% following the treatment with Nanogels, it was largely restored 24 h later. Effect of Nanogels on various respiratory components of cells was reversible too, and, therefore, resulted in low immediate cell death. Nanogel alone and formulations with AZT-TP demonstrated a much lower mitochondrial toxicity than AZT. As an example of potential antiviral applications of low-toxic Nanogel carriers, a 5'-triphosphorylated Ribavirin-Nanogel formulation was prepared that demonstrated a 30-fold decrease in effective drug concentration (EC(90)) and, totally, a 10-fold increase in selectivity index compared to the drug alone in MDCK cells infected with influenza A virus.

Topics: Adenosine Triphosphate; Animals; Antiviral Agents; Breast Neoplasms; Cell Line; Cell Line, Tumor; Cell Survival; Dideoxynucleotides; Dogs; Dose-Response Relationship, Drug; Drug Carriers; Female; Fluorescent Dyes; Formazans; Humans; Influenza A virus; Inhibitory Concentration 50; Kidney; L-Lactate Dehydrogenase; Luminescent Measurements; Membrane Potentials; Mitochondria; Nanogels; Nanotechnology; Polyethylene Glycols; Polyethyleneimine; Rhodamines; Ribavirin; Sensitivity and Specificity; Tetrazolium Salts; Thymine Nucleotides; Zidovudine

MTT is taken up by cells by endocytosis and reduced to formazan in the endosomal/lysosomal compartment. Formazan is deposited intracellularly as blue granules and is later exocytosed as needle-like formazan crystals. The present study involves an analysis of the pattern of exocytosis of MTT in different cell types showing clearcut differences in the response that can be associated to their ability to phagocytose. To further assess the characteristics of the exocytic mechanism of MTT/formazan, different experimental conditions were assayed. When culture medium with decreasing serum concentration was used as a metabolic modulator no variations were observed in the proportion of cells with formazan crystals. Conversely, the markedly sensitivity of phagocytic cells to increasing concentrations of genistein constituted a remarkable difference with non-phagocytic cells. These results must be considered when the modulation of MTT exocytosis is used as a signal of the progress of human diseases.

Topics: Animals; Breast Neoplasms; Cell Line; Cell Line, Tumor; Culture Media; Endosomes; Exocytosis; Female; Formazans; Genistein; Humans; Kinetics; Macrophages; Mice; Mice, Inbred Strains; Phagocytes; Tetrazolium Salts

Using three cytotoxicity assays, we have investigated the effect of the spermine analogue N1,N11-diethylnorspermine (DENSPM) on four human breast cancer cell lines with different known genetic lesions. Cells were seeded in 96 well plates and DENSPM was added 24 h later to give final concentrations from 0.1 to 100 microM. At 24, 48 and 72 h of treatment, the protein content was determined with a modified Lowry assay. Mitochondrial activity was determined with the AlamarBlue and MTT assays. These two assays differ with respect to where in the electron transport chain the reduction of the substrate takes place. Treatment with increasing concentrations of DENSPM resulted in differential responses in the four cell lines. There was a good of agreement between the protein content and the MTT assay showing increased negative effect with increased dose of DENSPM. The AlamarBlue assay on the other hand showed a stimulation of substrate reduction compared to control at DENSPM concentrations that were inhibitory according to the protein content and MTT assay. Thus, the data clearly show that the MTT and AlamarBlue assays are not equivalent. Importantly, the AlamarBlue assay presumably also reflects cytoplasmic reduction of the substrate through DENSPM-induced mechanisms.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Female; Formazans; Humans; Spermine; Tetrazolium Salts

A high dietary intake of cruciferous vegetables has been associated with a reduction in numerous human pathologies particularly cancer. In the current study, we examined the inhibitory effects of broccoli (Brassica oleracea var. italica) and watercress (Rorripa nasturtium aquaticum) extracts on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cancer cell invasion and matrix metalloproteinase-9 activity using human MDA-MB-231 breast cancer cells. Aberrant overexpression of matrix metalloproteinases, including metalloproteinase-9, is associated with increased invasive potential in cancer cell lines. Our results demonstrate that extracts of broccoli and Rorripa suppressed TPA-induced MMP-9 activity and invasiveness in a concentration dependent manner as determined by zymographic analysis. Furthermore, fractionation of individual extracts followed by liquid chromatography mass spectroscopy analysis (LC-MS) revealed that the inhibitory effects of each vegetable were associated with the presence of 4-methysulfinylbutyl (sulforaphane) and 7-methylsulphinylheptyl isothiocyanates. Taken together, our data indicate that isothiocyanates derived form broccoli and Rorripa inhibit metalloproteinase 9 activities and also suppress the invasive potential of human MDA-MB-231 breast cancer cells in vitro. The inhibitory effects observed in the current study may contribute to the suppression of carcinogenesis by diets high in cruciferous vegetables.

Topics: Anticarcinogenic Agents; Brassica; Breast Neoplasms; Carcinogens; Cell Line, Tumor; Cell Survival; Collagen; Drug Combinations; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Female; Formazans; Humans; Isothiocyanates; L-Lactate Dehydrogenase; Laminin; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Nasturtium; Plant Extracts; Proteoglycans; Sulfoxides; Tetradecanoylphorbol Acetate; Tetrazolium Salts; Thiocyanates

Zearalenone is a naturally occurring estrogenic contaminant of moldy feeds and is present in high concentrations in dairy products and cereals. Zearalenone was postulated to contribute to the overall estrogen load of women, but the mechanisms of its action are not known. We demonstrated that zearalenone could stimulate the growth of estrogen receptor-positive human breast carcinoma cell line MCF-7. In addition, zearalenone functioned as an antiapoptotic agent by increasing the survival of MCF-7 cell cultures undergoing apoptosis caused by serum withdrawal. Treatment of these cells with 100 nM zearalenone induced cell-cycle transit after increases in the expression of c-myc mRNA and cyclins D1, A, and B1 and downregulation of p27(Kip-1). G(1)/G(2)-phase kinase activity and phosphorylation of the retinoblastoma gene product was also evident. Flow cytometric analysis demonstrated entry of cells into the S and G(2)/M phases of the cell cycle, and phosphorylation of histone H3 occurred 36 h after zearalenone treatment. Ectopic expression of a dominant-negative p21(ras) completely abolished the zearalenone-induced DNA synthesis in these cells, and the specific inhibitor PD98059 for mitogen/extracellular-regulated protein kinase kinase arrested S-phase entry induced by zearalenone. These data suggest that the mitogen-activated protein kinase signaling cascade is required for zearalenone's effects on cell-cycle progression in MCF-7 cells. Given the presence of this mycotoxin in cereals, milk, and meat, the possibility that zearalenone is a potential promoter of breast cancer tumorigenesis should be investigated further. Mol. Carcinog. 30:88-98, 2001.

Topics: Adenoviridae; Annexin A5; Blotting, Northern; Blotting, Western; Breast Neoplasms; Bromodeoxyuridine; Cell Cycle; Cell Cycle Proteins; Cell Survival; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p27; Down-Regulation; Estrogens, Non-Steroidal; Female; Flow Cytometry; Formazans; Genes, myc; Humans; Luciferases; Microtubule-Associated Proteins; Mitogen-Activated Protein Kinases; Mitosis; Phosphorylation; Proto-Oncogene Proteins p21(ras); Signal Transduction; Tetrazolium Salts; Tumor Cells, Cultured; Tumor Suppressor Proteins; Zearalenone

This study was performed to investigate the effect of cholesterol content, surface charge and sterical stabilization on the physico-chemical properties of liposomes prepared from the cancerostatic alkylphospholipid, octadecyl-1,1-dimethyl-piperidino-4-yl-phosphate (D21266), and their relationship to in vitro cytotoxicity. Stable incorporation of OPP into liposomes was found to be highly dependent on the cholesterol content. 31P-NMR spectroscopy as well as analysis of the lipid composition of OPP-containing liposome formulations revealed an increase in the amount of non-liposome-associated, micellar OPP as the cholesterol content decreased. The fraction of non-liposome-associated OPP constituted about 10% of total OPP when cholesterol was present in equimolar amounts (45.5/45.5 mol %) and increased to approximately 30% at a twofold excess of OPP over cholesterol (58.8/29.4 mol %). In monolayer incorporation studies it was shown that the existence of an increasing micellar pool of lipids leads to increased lipid transfer into the target monolayer. Liposome formulations containing more OPP than cholesterol were also found to display greater cytotoxicity. However, all liposome formulations were less cytotxic than pure (micellar) OPP. Cytotoxicity was not affected by the incorporation of N-methoxy-polyethyleneglycol2000-phosphoethanolamine, a lipid that is known to reduce liposome uptake into phagocytic cells. The results demonstrate that the increase in cell toxicity correlates with the increase in non-liposome-associated, micellar OPP, which can readily exchange into cellular membranes.

Topics: Breast Neoplasms; Cell Division; Cell Survival; Chemistry, Pharmaceutical; Cholesterol; Ethanolamines; Female; Fluoresceins; Formazans; Humans; Liposomes; Lipoxygenase Inhibitors; Magnetic Resonance Spectroscopy; Micelles; Phenylpropionates; Polyethylene Glycols; Tetrazolium Salts; Tumor Cells, Cultured