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)

Antioxidants play an important role in inhibiting and scavenging radicals, thus providing protection to humans against infections and degenerative diseases. Literature shows that the antioxidant activity is high on herbal and vegetable plants. Realizing the fact, this research was carried out to determine total antioxidant activity and the potential anticancer properties in three types of selected local vegetable shoots such as Diplazium esculentum (paku shoot), Manihot utillissima (tapioca shoot) and Sauropous androgynus (cekur manis). The research was also done to determine the effect of boiling, on total antioxidant activity whereby samples of fresh shoots are compared with samples of boiled shoots. In every case, antioxidant activity is compared to alpha-tocopherol and two methods of extraction used are the organic and the aqueous methods. Besides that, two research methods used were the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) with absorbance of 500 nm and 532 nm respectively. Oneway ANOVA test at P <0.05 determines significant differences between various samples. In the cytotoxic study, the ethanolic extract and several cell lines i.e. breast cancer (MDA-MB-231 and MCF-7), colon cancer (Caco-2), liver cancer (HepG2) and normal liver (Chang liver) were used. The IC50-value was determined by using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The antioxidant study found that all the samples in both aqueous and organic extraction were significantly different. The total antioxidant activity values of aqueous extract in descending order are as follows : M. utilissima (fresh)> D. esculentum (fresh) > S.androgynus (fresh) > M.utilissima (boiled) > D. esculentum (boiled) > S.androgynus (boiled). It also was found that S.androgynus shoots ethanolic extract was able to inhibit the viability of the breast cancer cell lines, MDA-MB-231 with the IC subset 50 value of 53.33 microg/ml. However, S.androgynus shoots and D. esculentum shoots ethanolic extracts did not inhibit the viability of MDA-MB-231 cell line. While, the tapioca shoot ethanolic extract was able to inhibit the viability of MCF-7 cell line with the IC50 value of 52.49 microg/ml. S.androgynus shoots and D.esculentum shoots ethanolic extracts did not give an IC50 value against the MCF-7 cell line. S.androgynus, tapioca and D.esculentum shoots ethanolic extracts did not show cytotoxic effect against the Caco-2 and HepG2. There was no IC50-value from any sample against Chang Liver cell line. In conclusion, the antioxidant activity of both fresh and boiled samples were higher than alpha-tocopherol, although fresh vegetable shoots were found to be higher in antioxidant activity compared to boiled shoots. This study also suggested that S.androgynus shoots and tapioca shoots have potential as an anticancer agent against certain breast tumours.
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PMID:Determination of total antioxidant activity in three types of local vegetables shoots and the cytotoxic effect of their ethanolic extracts against different cancer cell lines. 1450 92

Apoptosis is a crucial event for anticancer drug efficacy. The signal pathways activated by anticancer drugs are classified as death receptor (DR) -dependent or -independent. The mechanisms by which anticancer drugs induce apoptosis via DR-dependent pathways are not fully understood. In the present study, we assessed differential activation of signal transduction pathways leading to apoptosis by anticancer drugs in breast cancer cell lines. Three breast cancer cell lines, MDA-MB-231, MCF-7, and MCF-7ADM, which is drug-resistant, were used. Drug sensitivity and apoptosis were assessed by MTT assay and TUNEL, respectively. Expression of apoptosis-related protein was assessed by Western blotting and RT-PCR. The sensitivities of MDA-MB-231 and MCF-7 cells to mitomycin C (MMC) and adriamycin (ADM) were similar. In contrast, sensitivity of MDA-MB-231 cells to paclitaxel (TXL) was 30-fold greater than that of MCF-7 cells, 0.03 micro M in MDA-MB-231 and 0.9 micro M in MCF-7 cells, respectively. Treatment with MMC increased expression of DR4 and Fas in a time-dependent manner in MDA-MB-231 cells. Treatment with ADM increased expression of DR4 and DR5 but not Fas, whereas treatment with TXL increased expression of Fas but not DR4 and DR5 in MDA-MB-231 cells. Although treatment of MCF-7 cells with ADM increased expression of DR4 and DR5 but not Fas, expression of DR4, DR5, and Fas by the drug-resistant cells did not change following treatment with ADM. Activation of Fas, DR4, and DR5 in drug-sensitive cells in response to anticancer drugs is dependent on the cytotoxic effect of each drug. In drug-resistant cells, apoptosis is induced via DR-independent pathways mediated by mitochondrial dysfunction.
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PMID:Death receptor-dependent and -independent pathways in anticancer drug-induced apoptosis of breast cancer cells. 1453 20

Retinoids exert different effects on malignant cells with various phenomena. They can induce differentiation and apoptosis in various cancer cells. However, the underlying mechanism of these effects is not clear. There are data related to the role of protein phosphatases during retinoid-induced leukemic cell differentiation. The aim of this study was to evaluate effects of the All trans retinoic acid (ATRA) on protein/serine phosphatases during ATRA induced apoptosis in the breast cancer cells. The MTT assay was used to determine drug-mediated cytotoxicity. A cell death detection ELISA kit was used for detection of the DNA fragments. The activity of serine/threonine protein phosphatases was assayed by the serine/threonine phosphatase system. The expression of serine/threonine protein phosphatases was evaluated by Western blot. During ATRA treatment, a significant decrease in the activity of serine/threonine phosphatases 2A, B and C occurred. The decreased activity of PP2A correlated with the up-regulation of PP2A catalytic and PP2A/B gamma, PP2A/B alpha regulatory subunits. The decrease in activity of the PP2B correlated with down-regulation of PP2B catalytic and up-regulation of PP2B regulatory subunit expression. In addition, there was an up-regulation in PP4C and down regulation in PP2C alpha/beta subunits protein expression. We demonstrated clear alteration in the activity and expression of serine/threonine protein phosphatases in breast cancer cells during ATRA treatment, and we suggest that the ATRA-induced apoptosis of the MCF-7 cells is significantly related to the phosphorylation dynamics.
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PMID:Alterations in the activity and expression of serine/threonine protein phosphatases during all trans retinoic acid-induced apoptosis in breast cancer cells. 1453 48

Ru(II) sulfoxide-maltolato complexes, Ru(ma)(2)(L)(2) (L = DMSO (1a) and TMSO (1b) or L(2) = BESE (1c)), were synthesized, as well as the analogous ethylmaltolato derivatives, Ru(etma)(2)(L)(2) (2a-c) (ma = 3-hydroxy-2-methylpyran-4-onate, etma = 2-ethyl-3-hydroxypyran-4-onate, TMSO = tetramethylene sulfoxide, BESE = 1,2-bis(ethylsulfinyl)ethane). A Ru(II) bidentate sulfoxide-metronidazole complex, RuCl(2)(BESE)(metro)(2) (3), was also synthesized (metro = metronidazole = 2-methyl-5-nitroimidazole-1-ethanol). The complexes were characterized generally by (1)H NMR, UV-vis, and IR spectroscopies, as well as MS, elemental analysis, solution conductivity, and cyclic voltammetry. The molecular structures of Ru(ma)(2)(S,R-BESE) (1c) and trans-RuCl(2)(R,R-BESE)(metro)(2) (3) were determined by X-ray crystallography. All sulfoxide ligands are S-bonded. The complexes were tested against human breast cancer cells (MDA-MB-435S) using an in vitro MTT assay, a colorimetric determination of cell viability: 2a,b exhibit the lowest IC(50) values of 190 +/- 10 and 220 +/- 10 microM, respectively. Cisplatin exhibits an IC(50) value of 30 +/- 5 microM.
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PMID:Ruthenium(II) sulfoxide-maltolato and -nitroimidazole complexes: synthesis and MTT assay. 1460 54

This study was designed to determine the antiproliferative, apoptotic and antioxidative properties of crude methanolic extract (CME) from the pericarp of Garcinia mangostana (family Guttiferae) using human breast cancer (SKBR3) cell line as a model system. SKBR3 cells were cultured in the presence of CME at various concentrations (0-50 microg/ml) for 48 h and the percentage of cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-di phenyl tetrazolium bromide (MTT) assay. CME showed a dose-dependent inhibition of cell proliferation with ED(50) of 9.25+/-0.64 microg/ml. We found that antiproliferative effect of CME was associated with apoptosis on breast cancer cell line by determinations of morphological changes and oligonucleosomal DNA fragments. In addition, CME at various concentrations and incubation times were also found to inhibit ROS production. These investigations suggested that the methanolic extract from the pericarp of Garcinia mangostana had strong antiproliferation, potent antioxidation and induction of apoptosis. Thus, it indicates that this substance can show different activities and has potential for cancer chemoprevention which were dose dependent as well as exposure time dependent.
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PMID:Antiproliferation, antioxidation and induction of apoptosis by Garcinia mangostana (mangosteen) on SKBR3 human breast cancer cell line. 1469 25

The combined cytostatic effect of doxorubicin and gestagens progesterone, medroxyprogesterone acetate, mecigestone, and butagest on doxorubicin-resistant and doxorubicin-sensitive human breast cancer MCF-7 cells was studied by the MTT assay. On the 6th day of incubation progesterone, medroxyprogesterone acetate, mecigestone, and butagest in high concentrations (10(-5) M) potentiated the cytostatic action of doxorubicin in sensitive and resistant cells by 30-50%. Potentiation of the cytostatic effect produced by doxorubicin in sensitive cells is related to intrinsic cytotoxic activity of gestagens. In resistant cells these changes are associated with potentiation of the effect of doxorubicin.
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PMID:Combined action of doxorubicin and gestagens on doxorubicin-sensitive and doxorubicin-resistant MCF-7 cells. 1496 60

Competitive inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase are commonly used in the clinic to treat hypercholesterolemia and have been reported to exert antitumor effects. Cerivastatin is a novel, synthetic and the most pharmacologically potent inhibitor of HMG-CoA reductase. We decided to examine the cytostatic/cytotoxic activity of cerivastatin against human breast cancer cell lines and to test whether the effects of cerivastatin could be potentiated by doxorubicin and cisplatin. Cytostatic/cytotoxic effects of cerivastatin used alone or in the combination with chemotherapeutics were measured with MTT assay. The cell cycle distribution and apoptosis induction were evaluated with flow cytometer. The expression of p21 and p27 cyclin-dependent kinase inhibitors was measured with Western blotting. Isobologram analysis was performed to study the drug interactions. We observed that cerivastatin exerts cytostatic/cytotoxic effects against four human tumor cell lines (T-47D, T4-2, MDA-MB-231, MCF-7). We also demonstrated that cerivastatin exerts growth inhibitory effect through induction of p21 cyclin-dependent kinase inhibitor and inhibition of cell cycle progression. In the two tumor cell lines studied, one sensitive (MDA-MB-231) and one moderately resistant (T4-2) to the cytostatic/cytotoxic effects of cerivastatin we examined the effects of combined treatment with cerivastatin and either doxorubicin or cisplatin. Cerivastatin potentiated cytostatic/cytotoxic effects of cisplatin against T4-2 cells and those of doxorubicin against both cell lines. In T4-2 cells the interaction between doxorubicin and cerivastatin and between cisplatin and cerivastatin was found to be synergistic. Altogether, these studies indicate that cerivastatin is another HMG-CoA reductase inhibitor with potent antitumor effects.
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PMID:Cerivastatin demonstrates enhanced antitumor activity against human breast cancer cell lines when used in combination with doxorubicin or cisplatin. 1506 36

Pseudogenes are classically thought of as nonfunctional DNA sequences due to their inability to be translated, or to produce a functional protein. Gap junctions, a multiprotein complex made of proteins called connexins, are involved in intercellular communication and are deregulated in many cancers. Connexin43 (Cx43) is the only connexin for which a pseudogene has been reported so far. The Cx43 pseudogene (PsiCx43) has all of the features of an expressed gene. We identified the presence of a PsiCx43 mRNA transcript in several cancer cell lines and in none of the normal mammary epithelial cells studied. Using an in vitro translation assay, we found that the PsiCx43 coding plasmid could be translated into a 43 kDa protein. This was further confirmed by expressing a PsiCx43-green fluorescence protein fusion protein in breast cancer MCF-7 cells. We then examined the functional significance of the PsiCx43. In both MTT growth and colony formation assays, significant growth inhibition was observed, a feature common to cells overexpressing the Cx43 gene. However, using a scrape-loading assay, we could not detect any effect on gap junctional intercellular communication. Based on our findings, PsiCx43 joins and enlarges the thus far restricted group of functionally transcribed and translated pseudogenes.
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PMID:Connexin43 pseudogene is expressed in tumor cells and inhibits growth. 1512 29

The omega-6 polyunsaturated fatty acid gamma-linolenic acid (GLA; 18:3n-6) has raised recent interest as novel anti-cancer agent as it possesses effective tumoricidal properties while not inducing damage to normal cells or creating harmful systemic side effects. The taxane docetaxel (Taxotere) is currently one of the most active microtubule-interfering agents for breast cancer. Despite this encouraging therapeutical potential, the clinical use of taxanes involves problems related to the solubility, toxicity and development of drug resistance, which may be partially dependent on the expression of HER-2/neu oncogene. Current trends in the treatment of human tumors are for drug combinations that result in improved responses as well as the ability to use less toxic concentrations of the drugs. Here, we examined the cytotoxic effects of GLA in combination with docetaxel against estrogen-dependent (MCF-7) and estrogen-independent (MDA-MB-231 and SK-Br3) human breast carcinoma cell lines. The cells were exposed simultaneously to GLA and docetaxel or sequentially to GLA followed by docetaxel for 24 h. Cytotoxicity was evaluated by the MTT assay, and the nature of the interactions between GLA and docetaxel (antagonism, additivity, and synergism) was analyzed by median effect and isobologram analyses. Interaction assessment showed that concurrent exposure to GLA plus docetaxel for 24 h resulted in synergism for MCF-7 and MDA-MB-231 cells, whereas an additive effect was observed in SK-Br3 cells. When exposure to GLA (24 and 48 h) was followed sequentially by docetaxel (24 h) a synergistic effect was observed in MDA-MB-231 and SK-Br3 cells, whereas an additive effect was found in MCF-7 cells. GLA-mediated increase in docetaxel cytotoxicity was only marginally abolished by Vitamin E, a lipid peroxidation inhibitor. Moreover, simultaneous exposure to GLA and docetaxel in the presence of the anti-oxidant Vitamin E also resulted in synergism, suggesting a limited influence of the oxidative status of GLA in achieving potentiation of docetaxel-induced cytotoxicity. Further experiments showed that GLA markedly decreased the expression of p185HER-2/neu oncoprotein in MCF-7 breast cancer cells (</=85%), and RT-PCR analysis revealed that HER-2/neu mRNA was selectively decreased in a concentration-dependent manner following GLA treatment. Therefore, our results show that the fatty acid GLA enhances the cytotoxicity of docetaxel in human breast cancer cells by mechanisms other than lipoperoxidation, and that GLA-induced transcriptional repression of HER-2/neu oncogene might be one component of the mechanisms of this interaction.
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PMID:Omega-6 polyunsaturated fatty acid gamma-linolenic acid (18:3n-6) enhances docetaxel (Taxotere) cytotoxicity in human breast carcinoma cells: Relationship to lipid peroxidation and HER-2/neu expression. 1513 62

Activity and expression of fatty acid synthase (FAS), a critical enzyme in the de novo biosynthesis of fatty acids in mammals, is exquisitely sensitive to nutritional regulation of lipogenesis in liver or adipose tissue. Surprisingly, a number of studies have demonstrated hyperactivity and overexpression of FAS (oncogenic antigen-519) in a biologically aggressive subset of human breast carcinomas, suggesting that FAS-dependent neoplastic lipogenesis is unresponsive to nutritional regulation. We have assessed the role of omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) on the enzymatic activity and protein expression of tumor-associated FAS in SK-Br3 human breast cancer cells, an experimental paradigm of FAS-overexpressing tumor cells in which FAS enzyme constitutes up to 28%, by weight, of the cytosolic proteins. Of the omega-3 PUFAs tested, alpha-linolenic acid (ALA) dramatically reduced FAS activity in a dose-dependent manner (up to 61%). omega-3 PUFA docosahexaenoic acid (DHA) demonstrated less marked but still significant inhibitory effects on FAS activity (up to 37%), whereas eicosapentaenoic acid (EPA) was not effective. Of the omega-6 fatty acids tested, gamma-linolenic acid (GLA) was the most effective dose-dependent inhibitor of FAS activity, with a greater than 75% FAS activity reduction. Remarkably, omega-6 PUFAs linoleic acid (LA) and arachidonic acid (ARA), suppressors of both hepatic and adipocytic FAS-dependent lipogenesis, had no significant inhibitory effects on the activity of tumor-associated FAS in SK-Br3 breast cancer cells. Western blotting studies showed that down-regulation of FAS protein expression tightly correlated with previously observed inhibition of FAS activity, suggesting that ALA-, DHA-, and GLA-induced changes in FAS activity resulted from effects at the protein level. We investigated whether the FAS inhibitory effect of GLA and omega-3 PUFAs correlated with a cytotoxic effect related to a peroxidative mechanism. Measurement of cell viability by MTT assay indicated a significant cellular toxicity after ALA and GLA exposures. Furthermore, we observed a significant correlation between the ability of PUFAs to repress FAS and cause cell toxicity. In the presence of anti-oxidants (vitamin E), ALA and GLA dramatically lost their ability to inhibit FAS activity. Interestingly, a combination of ALA and GLA was FAS inhibitory in an additive manner, and this FAS repression was only partially reversible by vitamin E. In examining the molecular mechanisms underlying resistance of breast cancer-associated FAS to normal dietary fatty acid-induced suppression, a dramatic decrease of FAS accumulation was found after exposure of SK-Br3 cells to mitogen-activated protein kinase (MAPK) extracellular signal-regulated kinase (MAPK ERK1/2) inhibitor U0126, phosphatidylinositol-3'-kinase (PI-3'K) blocker LY294002, and/or anti-HER-2/neu antibody trastuzumab. Interestingly, a long-term exposure to pharmacological inhibitors of FAS activity cerulenin [(2S,3R) 2,3-epoxy-4-oxo-7E,10E-dodecadienamide] or C75 also resulted in a significant reduction of FAS accumulation. These data indicate that: a) GLA- and omega-3 PUFA-induced repression of tumor-associated FAS may result, at least in part, from a non-specific cytotoxic effect due to peroxidative mechanisms; b) alternatively, GLA and omega-3 PUFAs have a suppressive effect on FAS expression and activity that can result in the accumulation of toxic fluxes of the FAS substrate malonyl-CoA; c) GLA- and/or omega-3 PUFA-induced repression of tumor-associated FAS may represent a novel mechanism of PUFA-induced cytotoxicity clinically useful against breast carcinomas carrying overexpression of FAS enzyme; d) fundamental differences in the ability of FAS gene to respond to normal fatty acid's regulatory actions in lipogenic tissues may account for the observed extremely high levels of FAS in breast carcinoma; and e) FAS overexpression in SK-Br3 breast cancer cells is driven by increases in HER-2/neu signaling, acting in major part through a constitutive downstream art through a constitutive downstream activation of the MAPK ERK1/2 and PI-3'K/AKT transduction cascades.
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PMID:Overexpression and hyperactivity of breast cancer-associated fatty acid synthase (oncogenic antigen-519) is insensitive to normal arachidonic fatty acid-induced suppression in lipogenic tissues but it is selectively inhibited by tumoricidal alpha-linolenic and gamma-linolenic fatty acids: a novel mechanism by which dietary fat can alter mammary tumorigenesis. 1513 77


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