Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0006142 (breast cancer)
160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lactoferrin (Lf) is a multifunctional iron-binding protein that was first identified in mammary secretions, but is synthesized by most mammalian tissues. The protein has a signal sequence that dictates secretion; it also has a nuclear localization sequence that facilitates entry into the cell nucleus. The mechanism of the latter action is currently unknown, but is thought to occur via a Lf receptor. Lactoferrin content of mammary tissue and secretions varies with developmental state; it is synthesized in mammary tissue at high levels during both pregnancy and involution, and during mammary infections. Using fluorescent (FITC)-labeled holo-bLf, we show that bovine primary epithelial cells and MCF-7 breast cancer cells do not translocate the exogenously added Lf to the nucleus after culture in serum free media (SFM). However, the supplementation of SFM with 1microM all-trans retinoic acid (atRA) caused breast cancer cells to gain the capacity to take up labeled bLf into the cell nucleus. Primary bovine mammary cells (MeBo) exhibited similar capacity in culture. This suggests that in addition to Lf, one or more components modulated by atRA, are necessary for nuclear translocation to occur. Transfection experiments with atRA treated MCF-7 cells containing retinoic acid response element reporter constructs showed that the extracellular application of lactoferrin alters reporter gene expression. Lactoferrin increased a DR5 luciferase response element in a dose-dependent manner only when atRA was applied. Immunocytochemical markers for the cell cycle (Ki67) and apoptotic events (Caspase-3 and PARP-85) showed that lactoferrin alters the atRA-induced phenotype, blocking apoptosis and maintaining cell cycle activity in both MCF-7 and MeBo cells in the presence of 1muM atRA. We propose that nuclear lactoferrin interacts with retinoic acid signaling pathways in cells and alters/blocks the signals so that cells remain in the cell cycle and/or do not enter the apoptotic pathway.
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PMID:Lactoferrin interaction with retinoid signaling: cell growth and apoptosis in mammary cells. 1616 21

Members of a novel series of pyrrolo-1,5-benzoxazepine (PBOX) compounds have been shown to induce apoptosis in a number of human leukemia cell lines of different haematological lineage, suggesting their potential as anti-cancer agents. In this study, we sought to determine if PBOX-6, a well characterised member of the PBOX series of compounds, is also an effective inhibitor of breast cancer growth. Two estrogen receptor (ER)-positive (MCF-7 and T-47-D) and two ER-negative (MDA-MB-231 and SK-BR-3) cell lines were examined. The 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to determine reduction in cell viability. PBOX-6 reduced the cell viability of all four cell lines tested, regardless of ER status, with IC(50) values ranging from 1.0 to 2.3 microM. PBOX-6 was most effective in the SK-BR-3 cells, which express high endogenous levels of the HER-2 oncogene. Overexpression of the HER-2 oncogene has been associated with aggressive disease and resistance to chemotherapy. The mechanism of PBOX-6-induced cell death was due to apoptosis, as indicated by the increased proportion of cells in the pre-G1 peak and poly(ADP-ribose) polymerase (PARP) cleavage. Moreover, intratumoural administration of PBOX-6 (7.5 mg/kg) significantly inhibited tumour growth in vivo in a mouse mammary carcinoma model (p=0.04, n=5, Student's t-test). Thus, PBOX-6 could be a promising anti-cancer agent for both hormone-dependent and -independent breast cancers.
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PMID:The pyrrolo-1,5-benzoxazepine, PBOX-6, inhibits the growth of breast cancer cells in vitro independent of estrogen receptor status and inhibits breast tumour growth in vivo. 1621 9

One-hundred twenty-four proteins have been identified in the soluble nuclear protein mixture from MCF-7 human breast cancer cells, of which more than 90% are classically categorized as nuclear proteins. Proteins were also studied from three drug resistant MDF-7 lines, selected previously from the same parent line by exposure to etoposide, to mitoxantrone, or to adriamycin in the presence of verapamil. Both quantitative gel comparisons and stable isotope labeling were used to identify a total of fourteen proteins whose abundances are altered by more than 2-fold in the three resistant lines. Several cytoskeleton proteins, cytokeratin 8, cytokeratin 19, septin 2, and alpha tropomyosin, are decreased in common across the three resistant cell lines. PARP-l (poly[ADP-ribosyl]transefrase or connexion) is found to be less abundant in all three resistant lines. Nucleolin is more abundant in lines resistant to etoposide and mitoxantrone, while the mitotic checkpoint protein BUB 3 is more abundant in the line resistant to adriamycin/verapamil.
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PMID:Proteomic evidence for roles for nucleolin and poly[ADP-ribosyl] transferase in drug resistance. 1621 10

We have previously demonstrated that deficiency of either the BRCA1 or BRCA2 breast cancer susceptibility proteins confers substantial cellular sensitivity to the inhibition of Poly(ADP-Ribose) polymerase (PARP). PARP is a key enzyme in the repair of single strand DNA damage via the Base Excision Repair pathway. We suggested that PARP inhibition produces persistent single-strand DNA breaks or gaps which degenerate into stalled replication forks and double-strand breaks, which may be repaired by homologous recombination, a process partially dependent on BRCA1 and BRCA2. It has recently been suggested that our results might be limited to certain BRCA2 mutations as the CAPAN-1 cell line, which carries a naturally occurring 6174delT mutation in one BRCA2 allele accompanied by loss of the wild-type allele, is apparently insensitive to two PARP inhibitors 3-aminobenzamide (IC50 33 microM) and NU1025 (IC50 400 nM). Here we show that CAPAN-1 cells are in fact very sensitive to the potent PARP inhibitors KU0058684 (IC50 3.2 nM) and KU0058948 (IC50 3.4 nM). In contrast, our results reveal much less sensitivity to a chemically related but much less active compound KU0051529 (IC50 730 nM) and to NU1025. These results confirm that treatment with potent PARP inhibitors remains an exciting potential therapy for cancers involving BRCA1 or BRCA2 deficiency.
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PMID:BRCA2-deficient CAPAN-1 cells are extremely sensitive to the inhibition of Poly (ADP-Ribose) polymerase: an issue of potency. 1625 2

In a search for new anticancer agents, we have identified serratamolide (AT514), a cyclodepsipeptide from Serratia marcescens 2170 that induces cell cycle arrest and apoptosis in various cancer cell lines. A cell viability assay showed that the concentrations that cause 50% inhibition (IC50) in human cancer cell lines range from 5.6 to 11.5 microM depending on the cell line. Flow cytometry analysis revealed that AT514 caused cell cycle arrest in G0/G1 or cell death, depending on the cell type and the length of time for which the cells were exposed to the drug. Subsequent studies revealed that AT514-induced cell death is caused by apoptosis, as indicated by caspases activation (8, 9, 2 and 3) and cleavage of poly (ADP-ribose) polymerase (PARP), release of cytochrome c and apoptosis inducing factor (AIF) from mitochondria, and the appearance of apoptotic bodies and DNA laddering. Alterations in protein levels of Bcl-2 family members might be involved in the mitochondrial disruption observed. AT514 induced p53 accumulation in wild-type p53 cells but cell death was observed in both deficient and wild-type p53 cells. Our results indicate that AT514 induces cell cycle arrest and apoptosis in breast cancer cells irrespectively of p53 status, suggesting that it might represent a potential new chemotherapeutic agent.
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PMID:Cell cycle arrest and proapoptotic effects of the anticancer cyclodepsipeptide serratamolide (AT514) are independent of p53 status in breast cancer cells. 1629 46

Antrodia camphorata (A. camphorata) is well known in Taiwan as a traditional Chinese medicine, and it has been shown to exhibit antioxidant and anticancer effects. In this study, therefore, its ability to induce apoptosis in cultured MCF-7 breast cancer cells was studied. Treatment of the MCF-7 cells with a variety of concentrations of the fermented culture broth of A. camphorata (25-150 microg/ml) resulted in dose- and time-dependent sequences of events marked by apoptosis, as shown by loss of cell viability, chromatin condensation, internucleosomal DNA fragmentation, and sub-G1 phase accumulation. Furthermore, apoptosis in the MCF-7 cells was accompanied by the release of cytochrome c, activation of caspase 3, and specific proteolytic cleavage of poly (ADP-ribose) polymerase (PARP). Although, the A. camphorata-induced apoptosis was associated with Bax protein levels, negligible Bcl-2 reduction was observed. Interestingly, A. camphorata induced dose-dependent reactive oxygen species (ROS) generation in MCF-7 cells. Analysis of the data suggests that A. camphorata exerts antiproliferative action and growth inhibition on MCF-7 cells through apoptosis induction, and that it may have anticancer properties valuable for application in drug products.
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PMID:Growth inhibition and induction of apoptosis in MCF-7 breast cancer cells by Antrodia camphorata. 1639 23

While the apoptosis-inducing ligand Apo2L/TRAIL is a promising new agent for the treatment of cancer, the sensitivity of cancer cells for induction of apoptosis by Apo2L/TRAIL varies considerably. Identification of agents that can be used in combination with Apo2L/TRAIL to enhance apoptosis in breast cancer cells would increase the potential utility of this agent as a breast cancer therapeutic. Here, we show that the histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), can sensitize Apo2L/TRAIL-resistant breast cancer cells to Apo2L/TRAIL-induced apoptosis. Importantly, neither Apo2L/TRAIL alone, nor in combination with SAHA, affected the viability of normal human cells in culture. Apo2L/TRAIL-resistant MDA-MB-231 breast cancer cells, generated by long-term culture in the continuous presence of Apo2L/TRAIL, were resensitized to Apo2L/TRAIL-induced apoptosis by SAHA. The sensitization of these cells by SAHA was accompanied by activation of caspase 8, caspase 9 and caspase 3 and was concomitant with Bid and PARP cleavage. The expression of the proapoptotic protein, Bax, increased significantly with SAHA treatment and high levels of Bax were maintained in the combined treatment with Apo2L/TRAIL. Treatment with SAHA increased cell surface expression of DR5 but not DR4. Interestingly, SAHA treatment also resulted in a significant increase in cell surface expression of DcR1. Taken together, our findings indicate that the use of these 2 agents in combination may be effective for the treatment of breast cancer.
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PMID:The histone deacetylase inhibitor, suberoylanilide hydroxamic acid, overcomes resistance of human breast cancer cells to Apo2L/TRAIL. 1655 Jun 2

Lauryl gallate is an antioxidant food additive showing low toxicity to normal cells. Here, its antiproliferative effect has been studied on three human breast cancer cell lines: estrogen-dependent, wild-type p53, MCF7; estrogen-independent, non-functional p53, MDA-MB-231 and MCF7 ADR, which overexpresses P-glycoprotein (P-gp) and displays a multidrug-resistant phenotype. Lauryl gallate inhibited proliferation and induced cell cycle alterations in all three cell lines without altering P-gp functionality in the drug-resistant cells. A stable arrest in G(1) phase was observed in MCF7, while a slow-down of cell cycle progression was induced in the other two cell lines. Lauryl gallate increased p53 expression only in MCF7, and upregulated p21(Cip1) and reduced cyclin D1 levels in all three cell lines. The induction of apoptosis, demonstrated by annexin V-FITC labeling, PARP cleavage and mitochondrial membrane depolarization and morphological alterations, were clearly detected in MCF7 ADR and MDA-MB-231 and to a minor extent in MCF7. Overexpression of Bcl-2 in MCF7 ADR cells demonstrated its protective role against morphological alterations and apoptosis. Lauryl gallate induction of p21(Cip1) and apoptosis observed in all three cell lines was regulated by Erk1/2 activation. These findings suggest a potential use of lauryl gallate against tumors harboring p53 mutations and drug-resistant phenotypes.
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PMID:Inhibition of proliferation and induction of apoptosis in human breast cancer cells by lauryl gallate. 1662 27

Breast cancer is one of the most common malignancies diagnosed in women and it is increasing in incidence. Siegesbeckia glabrescens (SG) has been used in traditional oriental medicine to treat cardiovascular diseases such as hypertension and angina pectoris. This study examined whether or not SG could induce apoptosis in human breast carcinoma cells. The treatment of estrogen-receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) cells with a variety of SG concentrations (0-1.0 mg/ml) resulted in a dose-dependent sequence of events that were marked by apoptosis. Furthermore, this apoptosis was accompanied by the cleavage of procaspase-9 and -3, and poly(ADP-ribose) polymerase (PARP) in the MCF-7 cells, and procaspase-8 and -3 and PARP in the MDA-MB-231 cells. Although, the SG-induced apoptosis was associated with a decrease in the level of Bcl-2 mRNA expression and an increase in the level of Bax mRNA expression in MCF-7 cells, there was no detectable change in the MDA-MB-231 cells. This suggests that SG might exert anti-proliferative action in human breast carcinoma cells via two different apoptotic pathways, namely an intrinsic signal in MCF-7 cells and an extrinsic signal in MDA-MB-231 cells. Therefore, regardless of the ER status, SG might be a promising pro-apoptotic agent for treating breast cancer.
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PMID:Siegesbeckia glabrescens induces apoptosis with different pathways in human MCF-7 and MDA-MB-231 breast carcinoma cells. 1668 80

Many cancer treatments induce cell death through lethal oxidative stress. Oxidative stress also induces the activation of the calcium/calmodulin-dependent kinases (CaM-Ks), CaM-KII and CaM-KIV. In turn, the CaM-Ks are known to induce the activation of antiapoptotic signaling pathways, such as Akt, ERK, and NF-kappaB in many different cell types. The aim of this study was to determine the role of CaM-Kinases in resistance to hydrogen peroxide and three oxidative stress-inducing cancer therapies in MCF-7 breast cancer cells. We found that oxidative stress induced CaM-Kinase activity in MCF-7 breast cancer cells and that CaM-K inhibition increased hydrogen peroxide-induced cell death in MCF-7 human breast cancer cells. When MCF-7 cells were treated with doxorubicin, ionizing radiation, or photodynamic therapy in the presence of a CaM-K inhibitor a greater level of cell killing was observed than when cells were treated with doxorubicin, ionizing radiation, or photodynamic therapy alone. In support of this finding, CaM-K inhibition increased hydrogen peroxide-induced apoptosis in MCF-7 cells, as determined by increased number of apoptotic cells, DNA fragmentation, and PARP cleavage. Pharmacological and molecular inhibition indicated that CaM-KII was participating in hydrogen peroxide-induced ERK phosphorylation in breast cancer cells indicating a potential mechanism by which this sensitization occurs. This is the first time that CaM-K inhibition is reported to sensitize cancer cells to reactive oxygen intermediate inducing cancer treatments.
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PMID:Inhibition of the CaM-kinases augments cell death in response to oxygen radicals and oxygen radical inducing cancer therapies in MCF-7 human breast cancer cells. 1699 4


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