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

Superparamagnetic magnetite nanoparticles were surface-modified with poly (ethylene glycol) (PEG) and folic acid, respectively, to improve their intracellular uptake and ability to target specific cells. PEG and folic acid were successfully immobilized on the surfaces of magnetite nanoparticles and characterized using fourier transform infrared spectra. The nanoparticle internalization into mouse macrophage (RAW 264.7) and human breast cancer (BT20) cells was visualized using both fluorescence and confocal microscopy, and quantified by inductively coupled plasma emission spectroscopy (ICP). After the cells were cultured for 48 h in the medium containing the nanoparticles modified with PEG or folic acid, the results of fluorescence and confocal microscopy showed that the nanoparticles were internalized into the cells. The ICP measurements indicated that the uptake amount of PEG-modified nanoparticles into macrophage cells was much lower than that of unmodified nanoparticles. while folic acid modification did not change the amount of the uptake. However, for breast cancer cells, both PEG and folic acid modification facilitated the nanoparticle internalization into the cells. Therefore, PEG and folic acid modification of magnetite nanoparticles could be used to resist the protein adsorption and thus avoid the particle recognition by macrophage cells, and to facilitate the nanoparticle uptake to specific cancer cells for cancer therapy and diagnosis.
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PMID:Surface modification of superparamagnetic magnetite nanoparticles and their intracellular uptake. 1192 61

Aromatase is the cytochrome P450 enzyme responsible for the last step of estrogen biosynthesis, and aromatase inhibitors constitute an important class of drugs in clinical use for the treatment of breast cancer. Nonsteroidal aromatase inhibitors (NSAIs) are competitive inhibitors of aromatase, which bind to the enzyme active site by coordinating the iron atom present in the heme group of the P450 protein. Presently, third generation NSAIs are in use, and research efforts are being carried out both to identify new molecules of therapeutic interest and to clarify the mechanism of action. In this article, we present a survey of the compounds that have been recently reported as NSAIs, to provide a broad view on the general structure-activity relationships of the class. Moreover, starting from the current knowledge of the mechanistic aspects of aromatase action and from recent theoretical work on the molecular modeling of both enzyme and inhibitors, we try to indicate a way to integrate these different studies in view of a more general understanding of the aromeatase-inhibitor system. Finally, some aspects regarding the possible future development of the field are considered briefly.
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PMID:Nonsteroidal aromatase inhibitors: recent advances. 1193 21

An x-ray fluorescence system with a synchrotron radiation source was used to quantify the levels of iron, copper and zinc in breast tissue specimens. Healthy tissue and breast carcinomas were investigated as an aid to understanding the mechanisms of breast cancer and as a possible complementary diagnostic tool. Eighty samples were measured in total. Twenty samples were matched pairs, i.e. 20 tumour samples with 20 corresponding healthy tissue specimens taken at a distance from the tumour. The remaining 40 samples consisted of 20 excised tumours and 20 healthy specimens from breast reduction surgeries. The levels of the elements of interest were quantified via calibration models constructed using the XRF response from standard solutions. The statistical analysis of the results indicates elevation of the levels of all three trace elements in the tumours. The effect is more prominent for copper and zinc while the contrast between healthy and diseased tissue is enhanced when comparing the independent specimens rather than the paired samples. Specifically, the ratio of mean tumour to mean healthy concentration for iron was 1.6 for the paired samples and 2.7 for the non-paired samples. The ratios describing copper content were 3.1 for paired and 3.6 for non-paired samples while for zinc they were 2.4 and 4.4 respectively.
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PMID:Concentrations of Fe, Cu and Zn in breast tissue: a synchrotron XRF study. 1216 90

This discussion of systemics covers oral contraceptives (OCs), injectables, depot medroxyprogesterone acetate (DMPA), known as Depo-Provera; and Norplant implants and injectable microspheres of norethisterone (NET). To minimize the side effects of OCs, pharmaceutical companies have worked to get OCs with the lowest possible dose of hormones that is still effective. Family Health International (FHI) has conducted several studies around the world comparing low-dose and standard-dose pills. A new FHI study will determine the acceptability of switching from standard-dose to low-dose pills. FHI also is undertaking a study of OCs with and without iron supplements among women with low hemoglobin counts to see if 7 days of iron each month causes a rise in the hemoglobin and if side effects are higher for the group taking iron supplements. The estrogen component of combined OCs has been associated with suppression of lactation. This is of serious concern, particularly for breastfeeding women with no alternative method of feeding their infants. While increasing the risk of some diseases (such as myocardial infarction and stroke), OCs provide protection from others. Over 100,000 Latin American women use injectable steroidal contraceptives. The World Health Organization (WHO) and FHI are collaborating on a study to compare 2 injectables. The study will evaluate effectiveness, side effects, and user satisfaction for each formulation. A new FHI study in Costa Rica addresses the question of whether longterm users of OCs or Depo-Provera run an increases risk of breast cancer or cervical cancer. The short-term safety and efficacy of Norplant implants has been established, and it has been approved for marketing in Finland. The primary objectives of FHI's clinical trials are to introduce the NORPLANT implant system into countries with no previous experience with this method and to determine overall acceptability of the method in different patient populations. By 1985 or early 1986, FHI will initiate studies in several Latin American countries. Every woman receiving the NORPLANT system will be followed up every 6 months for 5 years, the life of the system. Animals studies of the NET microspheres are concluding. There are plans to test it in a small number of women.
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PMID:Systemics. 1228 Jan 31

Diets containing substantial amounts of red meat may increase the risk of colorectal, pancreatic, breast, prostate, and renal cancer. The association with red meat intake may be due to a combination of factors, such as content of fat, protein, and iron, and/or meat preparation (e.g. cooking or preserving methods). Laboratory results have shown that meats cooked at high temperatures contain heterocyclic amines (HCAs) known to be mutagenic and carcinogenic in animals. Many older epidemiologic studies of colon cancer using surrogates for HCA exposure from meat (for example, doneness level, surface browning, frying, intake of gravy) have produced suggestive but inconsistent results. These discrepancies may have resulted in part from having used dietary questionnaires that combined meat-cooking practices in ways that made the intake of HCAs difficult to estimate. Thus, over the last decade we have taken a multidisciplinary approach to investigating whether the association with red meat intake can be explained by meat-cooking practices that produce mutagens/carcinogens. To estimate intake, a database for HCAs have been developed and used in conjunction with a validated meat-cooking food frequency questionnaire (FFQ). To develop biological markers of internal exposure, a metabolic study was conducted where subjects consumed controlled amounts of meat cooked at low and high temperatures. The role of meat type, cooking methods, doneness levels, and meat-cooking mutagens were examined in case-control studies of colorectal adenomas, lung, and breast cancers using both questionnaire information and biomarkers. In a case-control study of colorectal adenomas, an increased risk was associated with a high intake of red meat. Most of this risk was due to intake of red meat cooked until well/very well done and/or by high-temperature cooking techniques such as grilling. Linking the FFQ information to HCA database, the impact several HCAs on risk was evaluated. An increased risk was associated with higher intake of MeIQx, possibly PhIP. Red meat, especially fried and/or well-done red meat, was associated with increased risk of lung cancer in a population-based case-control study. In addition, an increase in risk was demonstrated among non-smokers and moderate smokers for MeIQx intake. In a case-control study of breast cancer well-done red meat and PhIP was associated with increased risk of breast cancer. In this manuscript I will provide one approach to studying the relation of meat cooking-mutagens and cancer risk and will suggest the types of studies that may be required in the future to clarify these associations.
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PMID:An epidemiologic approach to studying heterocyclic amines. 1235 Nov 59

Iron lactate has been used as a food additive for iron supplementation. The present study was conducted to determine whether it might have carcinogenic potential. A total of 150 male and 150 female Fischer 344 rats were divided into three groups and fed basal diet containing 0, 1 or 2% of iron lactate for 104 weeks. No iron lactate-induced tumors were observed in any groups, although the incidences of pancreatic acinar cell and endometrial gland hyperplasias were increased in males and females, respectively, in the 2% group. Thus our in vivo animal data indicate that iron lactate lacks carcinogenicity in male and female F344 rats. However, estrogenic effects might be concluded based on the data for endometrial lesions. In a second experiment, an estrogen responsive rat pituitary tumor cell line, MtT/Se, and a human breast cancer cell line, MCF-7, were therefore employed to examine the estrogenic potential of iron lactate with regard to receptor binding affinity and ERE-reporter gene activation. Results in both cases were negative. Further investigations are needed to elucidate the mechanisms of induction of pancreatic and endometrial proliferative lesions by iron lactate.
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PMID:Iron lactate induction of pancreatic and endometrial proliferative lesions and a lack of increased tumors in a 104-week carcinogenicity study in F344 rats. 1238 6

The objective of this study was to compare levels of four elements (zinc, copper, selenium, and iron) in the serum and tissue of 68 breast tumor patients (benign and malignant), from a teaching hospital in central Taiwan. Samples of normal tissue (5 cm away from tumor) were also taken from patients with malignant tumors. Only serum was taken from the 25 healthy persons in the control group. Results showed that Zn, Cu, Se, Fe, Cu/Zn, Cu/Se, and Cu/Fe were present in different amounts in the serum of each of the three groups. Zn and Se levels were lower in the serum of the two tumor groups compared to the control group. In tissue samples, Zn, Cu, Se, and Fe concentrations were different in each of the three groups. The malignant tissue had the highest levels of all four elements. In advanced-stage malignant tumors, levels of Cu and the ratios of Cu/Fe and Cu/Zn (in both serum and tissue) were highest. The ratios of serum Cu/Zn, Cu/Fe, and Cu/Se were also higher in malignant patients. The cutoff value of serum Cu/Zn was 1.2 (sensitivity and specificity were both 100%). The Cu/Zn ratio was highest in the advanced stages of cancer and was a better diagnostic tool for breast cancer than Cu/Se and Cu/Fe. The authors suggest that change of trace elements in serum and tissue might be useful and significant as biomarkers involving the initial plastic process.
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PMID:Serum and tissue trace elements in patients with breast cancer in Taiwan. 1241 46

Transferrin (Tf) is an iron transport protein expressed in MCF-7 human breast cancer cells. In nuclear run-on assays, 17beta-estradiol (E2) increased the rate of Tf gene expression approximately 3-fold within 1 h after treatment and reporter gene activity was also induced in MCF-7 cells transfected with a construct containing a -3600 to +39 Tf gene promoter insert. Deletion and mutation analysis identified an E2-responsive promoter region between -811 and -762, which was GC-rich (80%) and contained two nonconsensus estrogen response elements (EREs). E2-responsiveness of this region was associated with a GGACA(N)(3)TGGCC motif (-803 to -791) which bound human estrogen receptor alpha (hERalpha) in gel mobility shift assays. In Drosophila Schneider SL-2 cells, the -811 to -752 was E2-responsive after cotransfection with hERalpha expression plasmid plus E2, whereas Sp1 protein did not induce transactivation. These studies confirm that E2 induces Tf gene expression through a nonconsensus distal ERE.
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PMID:Estrogen regulation of transferrin gene expression in MCF-7 human breast cancer cells. 1245 33

The purpose of this study was to evaluate enhancement (signal loss) of the axillary lymph nodes on MR lymphography after intramammary injection of superparamagnetic iron oxide (Ferumoxides) for detection of the sentinel lymph node. MR lymphography was performed in a total of 11 patients with breast cancer without palpable axillary lymph node swelling before operation. Coronal and axial images were obtained before and after intramammary injection of 1.5 ml Ferumoxides adjacent to the breast tumor. In all patients, decreased intensity was recognized in the axillary lymph nodes. MR lymphography could detect the sentinel lymph node with its decreased signal intensity 20 minutes after the intramammary injection of Ferumoxides.
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PMID:[Sentinel lymph node after intramammary injection of superparamagnetic iron oxide]. 1250 94

It is known that the interruption of normal iron metabolism with chelators of iron, toxic metals, toxic metals bound to transferrin, or anti-transferrin receptor antibodies leads to significant inhibition of tumor cell growth in cell culture systems and animal models. In the present study, we found that iron depletion was produced by the iron chelator deferoxamine mesylate, the free toxic metals gallium or indium, and the toxic metals gallium or indium bound to transferrin in the MCF-7 human breast cancer cell line, and this induced the condensation and fragmentation of chromatin, and the formation of DNA fragments characteristic of apoptosis. The induction of apoptosis was quantitated with acridine orange and ethidium bromide staining of apoptotic cells, separation of fragmented DNA from radiolabeled cells, and in situ terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) assays. The apoptosis, caused by deferoxamine mesylate, and gallium or indium bound to transferrin in the MCF-7 cells, can be completely inhibited by excess ferric chloride or equimolar iron-loaded transferrin. Gallium-transferrin and indium-transferrin complexes induced more apoptosis than their respective salts in the MCF-7 cells. Deferoxamine mesylate induced a small increase in the endogenous expression of both the bcl-2 and bax genes in the MCF-7 cells and this can be prevented by ferric chloride. In the 13762NF rat mammary adenocarcinoma model, in situ TUNEL assays showed that the iron-deficiency following a low iron diet or intravenous injection of deferoxamine mesylate produced 5.32 +/- 3.90% and 6.46 +/- 3.58% of apoptotic cells, respectively, compared to 2.01 +/- 1.20% of apoptotic cells in the control rats maintained on a normal diet (p < 0.05 and p < 0.01, respectively, Student's t-test). This is the first report of iron depletion caused by a low iron diet or deferoxamine mesylate treatment inducing apoptosis in rats bearing the 13762NF marnmary adenocarcinoma.
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PMID:Induction of apoptosis by iron depletion in the human breast cancer MCF-7 cell line and the 13762NF rat mammary adenocarcinoma in vivo. 1252 82


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