RESUMO
BACKGROUND: Pediatric oral hemangiomas are benign vascular tumors that can be seen from birth, particularly in females. Hemangiomas are most frequent located in the lips and usually regress spontaneously, thus they do not require any type of treatment in most cases. The present scoping review pretended to synthesize the most relevant and currently available information from the international dental literature published in the last 25 years, regarding the management of pediatric oral hemangiomas. MATERIAL AND METHODS: An exhaustive literature search was performed in four electronic databases (PubMed, Embase, Google Scholar, and Cochrane). Initially, 241 related titles and abstracts were found. After the duplication removal, screening, and assessment processes, 37 records were included for full-text reading. Finally, 20 articles in the English language were included in the scoping review for data extraction and assessment. RESULTS: We identified and subsequently discussed three fundamental issues associated to the management of pediatric oral hemangiomas: (i) clinical characteristics, differential diagnosis, and histopathological findings; (ii) evolution and complications; and (iii) current available treatment modalities. CONCLUSIONS: Although these like-tumor lesions are uncommon, pediatric dentistry practitioners must be familiar with the inherent clinical characteristics, diagnosis approaches, and currently available treatment options. Nowadays, surgical removal and non-invasive medical/pharmacologic therapies are the best management modalities for pediatric oral hemangiomas.
Assuntos
Hemangioma , Neoplasias Bucais , Criança , Humanos , LactenteRESUMO
BACKGROUND: Oral and pharynx cancer represent a serious global problem, reaching an incidence of half a million cases annually. The role of tobacco and alcohol have been studied and proven to be one of its risk factors. We also know that mouthwashes contain a variable percentage of alcohol, so there is a reasonable concern about their role in carcinogenesis. MATERIALS AND METHODS: To answer the PICOS (Population; Intervention; Comparison; Outcomes; Study) question: Do patients (Population) who use alcohol-based mouthwashes (Intervention) compared to those who do not use them (Comparison) have higher acetaldehyde levels in saliva or higher risk of oral cancer development? (Outcomes) Meta-analyses, systematic reviews, randomized and non-randomized clinical trials, case-control studies, and prospective and retrospective cohort studies were included (Study). Two independent authors conducted literature screening through MEDLINE, Scopus and the Cochrane Library, and they also conducted article and data extraction to undertake quality analyses. The main outcome measures were salivary acetaldehyde levels or the risk of oral cancer development. The most relevant data was extracted and the risk of bias from the studies included was also evaluated. RESULTS: Out of 497 potentially eligible papers, 8 studies were included in the qualitative analysis which include a total of 43,499 subjects: two meta-analyses, a clinical trial, three case-control studies and two cohort studies. One study (n = 3,926) found a relationship between alcohol mouthwash and oral cancer, two studies (n = 25,033) found this relationship when a high frequency of mouthwash was present, three studies (n = 14,482) failed to find this relationship and 2 studies (n = 58) found a temporary increase of acetaldehyde levels in saliva after alcohol mouthwash. CONCLUSIONS: It cannot be guaranteed that the use of mouthwash represents an independent risk factor for the development of head and neck cancer. However, the risk does increase when it occurs in association with other carcinogenic risk factors.
Assuntos
Neoplasias Bucais , Antissépticos Bucais , Humanos , Estudos Prospectivos , Estudos Retrospectivos , Fatores de RiscoRESUMO
A diversified approach involving chemical, microbiological and ecotoxicity assessment of soil polluted by heavy mineral oil was adopted, in order to improve our understanding of the biodegradability of pollutants, microbial community dynamics and ecotoxicological effects of various bioremediation strategies. With the aim of improving hydrocarbon degradation, the following bioremediation treatments were assayed: i) addition of inorganic nutrients; ii) addition of the rhamnolipid-based biosurfactant M(AT10); iii) inoculation of an aliphatic hydrocarbon-degrading microbial consortium (TD); and iv) inoculation of a known hydrocarbon-degrading white-rot fungus strain of Trametes versicolor. After 200 days, all the bioremediation assays achieved between 30% and 50% total petroleum hydrocarbon (TPH) biodegradation, with the T. versicolor inoculation degrading it the most. Biostimulation and T. versicolor inoculation promoted the Brevundimonas genus concurrently with other α-proteobacteria, ß-proteobacteria and Cytophaga-Flexibacter-Bacteroides (CFB) as well as Actinobacteria groups. However, T. versicolor inoculation, which produced the highest hydrocarbon degradation in soil, also promoted autochthonous Gram-positive bacterial groups, such as Firmicutes and Actinobacteria. An acute toxicity test using Eisenia fetida confirmed the improvement in the quality of the soil after all biostimulation and bioaugmentation strategies.
Assuntos
Petróleo/metabolismo , Petróleo/microbiologia , Poluentes do Solo/metabolismo , Biodegradação Ambiental , Glicolipídeos/metabolismo , Consórcios Microbianos/fisiologia , Microbiologia do Solo , Tensoativos/metabolismo , Testes de Toxicidade Aguda/métodosRESUMO
A região amazônica é detentora de uma vasta biodiversidade de frutos, porém pouco explorada quanto o seu potencial nutricional e econômico. Dentre estes frutos destaca-se o maracujá-do-mato (Passiflora nitida Kunth), espécie silvestre, de fruto comestível, com sabor exótico e de boa aceitabilidade para consumo. No presente estudo objetivou-se analisar as características nutricionais do mesocarpo do fruto da P. nitida e avaliar o potencial hipoglicemiante em ratos normais e diabéticos. A farinha do mesocarpo do fruto foi elaborada e analisada quanto a composição centesimal. A atividade hipoglicemiante foi avaliada por meio de dois modelos experimentais em ratos Wistar. O mesocarpo apresentou baixa concentração de macronutrientes e alto teor de umidade, cinzas e fibras. No experimento agudo, após 15 minutos da administração da sacarose, os níveis glicêmicos foram de 146±12 mg dL-1 no grupo controle e 112±2,5 mg dL-1, no grupo que recebeu 1g kg-1 de peso da farinha. No experimento crônico, após 21 dias, houve redução de 493 mg dL-1 para 302 mg dL-1 (38,7 %) e 195 mg dL-1 (60,4%) na glicemia nos grupos que foram tratados com 20 e 40% de ração enriquecida com a farinha, respectivamente, em relação ao grupo diabético não tratado. Em ambos os modelos experimentais, a farinha do mesocarpo mostrou-se eficaz na redução da glicemia. O fruto de P. nitida mostrou-se um produto natural em potencial para o controle da glicemia no diabetes.
The Amazon region has a vast biodiversity of fruits but is little explored as to its nutritional and economic potential. Among these fruits is "maracuja-do-mato" (Passiflora nitida Kunth), a wild species of edible fruit with exotic flavor and good acceptability for consumption. The aim of the present study was to analyze the nutritional characteristics of P. nitida fruit mesocarp and to evaluate its hypoglycemic potential in normal and diabetic rats. Flour from the fruit mesocarp was prepared and analyzed as to its centesimal composition. Hypoglycemic activity was assessed by means of two experimental models in Wistar rats. The mesocarp showed low concentration of macronutrients and high humidity, ash and fiber content. In the acute experiment, after 15 minutes of sucrose administration, glucose levels were 146 ± 12 mg dL-1 in the control group and 112 ± 2.5 mg dL-1 in the group receiving 1 g kg-1 flour weight. In the chronic experiment, after 21 days, glucose levels reduced from 493 mg dL-1 to 302 mg dL-1 (38.7%) and 195 mg dL-1 (60.4%) in the groups treated with 20 and 40% animal food enriched with the flour, respectively, in relation to the diabetic untreated group. In both experimental models, the mesocarp flour was effective in reducing blood glucose. P. nitida fruit seems to be a potential natural product in the glycemic control of diabetes.
Assuntos
Animais , Masculino , Ratos , Passiflora/metabolismo , Farinha/classificação , Hipoglicemiantes/análise , Diabetes Mellitus/prevenção & controleRESUMO
Fractionation of the cyclohexane extract from the stem bark powder of Zanthoxylum madagascariense led to the isolation of a new benzophenanthridine-type alkaloid, hydrochloride of 2,3-methylendioxy-8-hydroxy- 7-methoxy-benzo[C]phenanthridine (Rutaceline), characterized on the basis of its spectral data. Rutaceline was evaluated for its antiproliferative capacity on the human colorectal adenocarcinoma (Caco-2) and the African green monkey kidney (Vero) cell lines. The 50% inhibition of cell growth (IC50) obtained after 24 h incubation was similar for both cells lines (110-115 microg/ml, i.e. 269-281 microM), but at 48 h the IC50 value for the Caco-2 cells was lower than for the Vero cells (20 microg/lml, i.e. 49 microM versus 90 microg/ml, i.e. 220 microM) indicating a higher cell growth inhibitory effect on the colon adenocarcinoma cells. At the respective IC50 concentrations, Rutaceline did not significantly induce apoptosis but induced cell cycle arrest in the GO/G1 phase, as well as a decrease of cells in S phase. Rutaceline also induced DNA fragmentation in both cell lines, as revealed by agarose gel electrophoresis, and a dose-dependent clastogenic effect in both cell lines as revealed by the Comet assay.
Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Benzofenantridinas/isolamento & purificação , Benzofenantridinas/farmacologia , Zanthoxylum , Adenocarcinoma , Animais , Antineoplásicos/química , Benzofenantridinas/química , Linhagem Celular , Linhagem Celular Tumoral , Chlorocebus aethiops , Neoplasias Colorretais , Humanos , Rim/efeitos dos fármacos , Cinética , Madagáscar , Células VeroRESUMO
Splenic iron stores are negligible in prepuberal rats, increasing quickly from the age of 2 months (at which moment sexual differences become apparent) and stabilizing around 3 months, when females show values approximately two-fold greater than males. Castration, adrenalectomy and hormone replacement studies show that the amount of iron stored depends directly on circulating oestrogens and is slightly but not significantly decreased, in our experimental conditions, by testosterone. The role of oestrogens is emphasized by the high correlation obtained, according to a hyperbolic regression model, between splenic iron values and doses of hormone administered to ovariectomized females. In ferrodeficient females (chronic phlebotomy), oestradiol had a positive effect on the replenishment of the stores, superior to that of iron dextran, and improved by combined treatment. However, iron levels found after a single dose were less than those found in nonphlebotomized animals.
Assuntos
Estradiol/uso terapêutico , Deficiências de Ferro , Baço/fisiopatologia , Adrenalectomia , Animais , Relação Dose-Resposta a Droga , Feminino , Hematócrito , Ferro/análise , Ferro/metabolismo , Masculino , Orquiectomia , Tamanho do Órgão , Ovariectomia , Flebotomia , Ratos , Ratos Wistar , Baço/química , Baço/metabolismoRESUMO
We have previously demonstrated lysis of non-established cultures of human mammary carcinoma cells by parvovirus H-1, which has little effect on the proliferation of corresponding normal cultures. In the present study, we examined this effect in a number of breast-tumour specimens and found them to differ as to the amplitude of their response to parvoviral attack. We first investigated whether the differences in cell sensitivity to parvovirus infection reflected the differentiation level of the initial tumour. Among the biochemical and anatomopathological indicators of original tumour differentiation, the presence of oestrogenic receptors (ER) was found to have a predictive value as to the sensitivity of derived cultures to the cytopathic effect of H-1 virus. The ER+ tumour-derived cultures showed an increased sensitivity to the lytic effect of H-1 virus compared with the ER-tumour-derived cultures, in spite of similar average proliferation rates for the two types of cultures. The proliferation rate was more heterogeneous among ER+ tumour-derived cultures and, in this group, the faster growing cultures were also the most sensitive. This observation was corroborated by the study of established cell lines retaining ER expression under in vitro culture conditions. Oestradiol was found to increase the sensitivity of these cells to the parvovirus in parallel with induction of proliferation. This effect appeared to be mediated by ER activation, since it was not observed in the ER-negative cell line MDA-MB-231. These data point to the importance of hormonal influences and cellular parameters, notably differentiation and proliferation, in determining the extent to which human cancer cells can be targets for the cytopathic effect of parvoviruses.
Assuntos
Neoplasias da Mama/complicações , Neoplasias da Mama/patologia , Infecções por Parvoviridae/complicações , Parvovirus/fisiologia , Neoplasias da Mama/química , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Sobrevivência Celular/fisiologia , Feminino , Humanos , Receptores de Estrogênio/análise , Células Tumorais CultivadasRESUMO
In MCF-7 cells, estrogen receptor (ER) elimination occurs rapidly under stimulation with estradiol (E2) at 1 nM ('ER processing'); cycloheximide (CHX) at 50 microM impedes this phenomenon. ER processing is also observed when E2 is removed after the first hour of incubation, indicating that the role of the hormone would be limited to the initiation of this process. When CHX is removed at the same time, receptor processing and, later, the induction of progesterone receptor (PgR) both proceed. The initial estrogenic signal which activates ER is therefore not influenced by CHX. In support of this conclusion, no effect of the drug on E2 binding affinity of residual ER was detected. A similar result was recorded for a series of estrogens and antiestrogens, indicating that CHX exerts no influence on the potential agonistic/antagonistic potency of any ligand. Size-exclusion chromatography (FPLC) revealed that [3H]E2-induced ER activation leads to the cleavage of the native receptor (67 kDa) into low molecular weight isoforms which subsequently become less detectable over time (proteolysis). In the presence of CHX, such ER isoforms persist, confirming the absence of interference of the drug with the activation step. When the cells were prelabelled with [3H]tamoxifen aziridine ([3H]TAZ) before their exposure to E2, ER cleavage could not be detected due to the lack of activation potency of the antiestrogenic ligand. However, the [3H]TAZ-ER complexes were subjected to E2-induced processing; CHX blocked this phenomenon, which is associated with the maintenance of ER synthesis and activation.
Assuntos
Cicloeximida/farmacologia , Estradiol/farmacologia , Inibidores da Síntese de Proteínas/farmacologia , Receptores de Estrogênio/efeitos dos fármacos , Ligação Competitiva/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Estradiol/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Puromicina/farmacologia , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
In 1986 we reported the appearance of a progestin binding protein in the human breast cancer cell line Evsa-T, originally described as lacking both estrogen and progesterone receptors (ER and PR). In this report we show that PR of this cell line displays a binding affinity for [3H]ORG 2058 and a sucrose gradient sedimentation profile similar to those ascribed to PR from MCF-7 or T47D breast cancer cell lines. PR from Evsa-T cells is down-regulated by the progestin R-5020 as well as by the two antiprogestins, ZK 112.993 and ZK 98.299, but does not confer growth sensitivity to these compounds. ER remains undetectable by ligand binding assay, enzyme immunoassay and northern blotting. Our Evsa-T clone could be a valuable model for assessing the mechanisms leading the ER-/PR+ phenotype occurring occasionally in breast cancers and frequently in meningiomas.
Assuntos
Neoplasias da Mama/patologia , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Neoplasias da Mama/metabolismo , Divisão Celular/efeitos dos fármacos , Citosol/metabolismo , Regulação para Baixo/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Gonanos/farmacologia , Antagonistas de Hormônios/farmacologia , Humanos , Mifepristona/análogos & derivados , Mifepristona/farmacologia , Pregnenodionas/metabolismo , Progestinas/antagonistas & inibidores , RNA Mensageiro/genética , RNA Neoplásico/genética , Receptores de Estrogênio/genética , Células Tumorais CultivadasRESUMO
Effect of estrogens and antiestrogens (AEs) on estrogen receptor (ER) half-life was analyzed in MCF-7 cells by assessing its progressive disappearance after covalent labeling in situ with [3H]tamoxifen aziridine ([3H]TAZ). Cells were incubated for 1 h with 20 nM [3H]TAZ either in the absence or presence of a 500-fold excess of unlabeled estradiol (E2) (non-specific binding). The entire ER population was labeled by this method as established by subsequent incubation of the cells with [125I]E2. [3H]TAZ labeled cells were maintained in culture for additional 5 h in the absence (control) or presence of increasing amounts (0.1 nM - 1 microM) of either a given estrogen (E2, estrone, diethylstilbestrol, bisphenol), a pure AE (RU 58 668, ICI 164 384) or an AE with residual estrogenic activity (RU 39 411, 4-hydroxytamoxifen, keoxifene). The progressive disappearance of nuclear and cytosolic [3H]TAZ-ER complex during 5 h incubation were assessed by their immunoprecipitation with anti-ER monoclonal antibody (H 222) followed by scintillation counting or SDS-PAGE and fluorography. Fading of labeled receptors was extremely slow (approximately 10% loss after 6 h) in absence of any hormone/antihormone indicating a long half-life of the [3H]TAZ-ER complex. Addition of estrogens as well as pure AEs led to a dramatic reduction of the half-life while AEs with residual estrogenic activity were extremely less efficient in this regard providing an explanation for the ability of latter compounds to up-regulate the receptor since they do not affect ER mRNA synthesis and stability. Receptor disappearance induced by estrogens was closely related to their binding affinity for ER. Newly synthesized ER emerged during the treatment with hormones or antihormones seems to be implicated in the phenomenon since [3H]TAZ was covalently bound and could, therefore, not be displaced by these compounds. Induction of synthesis of a short half-life peptide(s) with degradative activity was demonstrated by addition of cycloheximide or puromycine (both at 50 microM) which completely blocked ER disappearance. The fact that no cleavage products of ER were detected by SDS-PAGE suggested a lysosomial hydrolysis. Hence, hormonal modulation of only a part of ERs may down-regulate their total population until it reaches the steady-state level.
Assuntos
Neoplasias da Mama/metabolismo , Antagonistas de Estrogênios/farmacologia , Estrogênios/farmacologia , Receptores de Estrogênio/metabolismo , Núcleo Celular/química , Cicloeximida/farmacologia , Citosol/química , Estradiol/metabolismo , Meia-Vida , Humanos , Indicadores e Reagentes , Peso Molecular , Inibidores da Síntese de Proteínas/farmacologia , Puromicina/farmacologia , RNA Mensageiro/biossíntese , RNA Mensageiro/metabolismo , Receptores de Estrogênio/análise , Receptores de Estrogênio/biossíntese , Receptores de Estrogênio/química , Tamoxifeno/análogos & derivados , Células Tumorais Cultivadas , Regulação para Cima/efeitos dos fármacosRESUMO
Two 11 beta-derivatives of estradiol (E2) were tested for their potential antiestrogenic activity in the MCF-7 breast cancer model: one contained a phenoxydimethylaminoethyl side-chain (RU 39,411), the other a pentafluoropentylsulfinyl side-chain (RU 58,668). The former compound displayed mixed estrogenic/antiestrogenic properties, while the latter indicated only an antiestrogenic activity. Both the compounds produced a growth inhibition of MCF-7 cells at doses related to their binding affinity for the estrogen receptor (ER); E2 suppressed this inhibition. The compounds also down-regulated the estrogen binding capacity of the cells but failed to reduce ER mRNA levels, indicating that the grafting of their side-chains prevented this antagonistic effect usually observed with steroidal estrogens. Assessment of ER levels by enzyme immunoassay revealed a marked increase with RU 39,411 and a decrease with RU 58,668; different mechanisms of action should, therefore, be considered. Finally, the estrogenic activity of RU 39,411 was demonstrated by its strong ability to induce synthesis of the progesterone receptor; RU 58,668 failed to display this agonistic activity.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Estradiol/análogos & derivados , Antagonistas de Estrogênios/uso terapêutico , Neoplasias da Mama/patologia , Regulação para Baixo/efeitos dos fármacos , Estradiol/uso terapêutico , Humanos , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Estrogen receptor (ER), antiestrogen binding sites (AEBS) and calmodulin (CaM) are potential targets of antiestrogen (AE) action. To analyse further which of these targets are primarily involved in the antiproliferative activity of these drugs against human breast cancers, two cell clones, namely the RTx6 and LY-2 variants, selected from MCF-7 cells for their resistance to high doses of tamoxifen (TAM) and the Keoxifen (KEO) analog LY 117018, respectively, were studied for their sensitivity to hydroxytamoxifen (OH-TAM) and KEO as well as the strong calmodulin antagonist calmidazolium. The effects of these drugs on both cell growth and progesterone receptor (PgR) concentration were assessed. Binding properties for ER, AEBS and CaM of each compound were also measured. Our results confirmed that basal growth of RTx6 and LY-2 cells was more resistant to OH-TAM and KEO than parent MCF-7 cells, although both displayed a significant inhibition at the highest doses assessed. In regard to calmidazolium inhibition, each variant behaved as did the MCF-7 line indicating that a modification at the CaM level was not responsible for their lower sensitivity to AEs. Nor could the association of CaM to ER which did not differ among all cell lines. Resistance of these variants was not related to AEBS in view of the total lack of such sites in RTx6 cells. However, under estrogenic growth stimulation such sites may play some role, since LY-2 cells in the presence of estradiol displayed a real antiestrogen-resistant pattern while RTx6 cells were more sensitive than MCF-7 cells to OH-TAM. This property was not found in the antagonism against estradiol-induced PgR synthesis which was observed with each variant. Thus the PgR concentration of RTx6 cells was strongly down-regulated by OH-TAM and KEO and reduced in LY-2 cells to the same extent as in MCF-7 cells. All these observations show that AE resistance is not entirely related to ER mediated events and that alterations at the ER and CaM levels are unlikely to account for the lower AE sensitivity of the variants investigated.
Assuntos
Calmodulina/metabolismo , Antagonistas de Estrogênios/farmacologia , Receptores de Estrogênio/metabolismo , Sítios de Ligação , Divisão Celular , Células Clonais , Resistência a Medicamentos , Humanos , Imidazóis/farmacologia , Pirrolidinas/farmacologia , Receptores de Progesterona/análise , Tamoxifeno/análogos & derivados , Tamoxifeno/farmacologia , Tiofenos/farmacologia , Células Tumorais CultivadasRESUMO
Incubation of MCF-7 cells with estradiol (E2) down-regulates estrogen receptor (ER) resulting in a progressive reduction of the capacity of cells to concentrate selectively [3H]E2. Scatchard plot analysis failed to detect any transformation of residual receptors into peptides of lower binding affinity. [3H]Estrone gave an identical ER disappearance pattern with an ER half-life comprised between 2 and 3 h. A similar value was established by incubating the cells with [3H]tamoxifenaziridine ([3H]TAZ) for 1 h before the addition of excessive unlabeled E2 which induced ER-down regulation and impeded any further labeling of the residual receptors. Submission of the [3H]TAZ labeled cell extracts to SDS-PAGE revealed no progressive emergence of low molecular weight cleavage products of the receptor (< 67 kDa). Two inhibitors of protein kinases, H-7 at 40 microM and H-89 at 20 microM, failed to block the E2-induced ER down-regulation. On the contrary, the protein phosphatases 1 and 2A inhibitor, okadaic acid, was effective with concentrations higher than 0.1 microM indicating that a dephosphorylation mechanism was involved in this phenomenon. Cycloheximide (CHX) also significantly reduced the receptor decrease at concentrations higher than 1 microM. G-C specific intercalating agents [actinomycin D (AMD) and chromomycin A3 at 1 microM] also prevented ER disappearance; ethidium bromide (EB) and quinacrine were ineffective. AMD and CHX operated immediately after their addition to the medium indicating an inhibitory action on the synthesis of an RNA and/or a peptide with high turnover rate involved in ER decline. Moreover, AMD produced its suppressive effects under conditions impeding any labeling of newly synthetized receptors (i.e. [3H]TAZ with an excess of unlabeled E2) rejecting the possibility of an increasing ER production which may partially hamper its disappearance. Finally, E2-induced ER mRNA down-regulation was similarly abolished by AMD while EB and CHX were devoid of effect.
Assuntos
Regulação para Baixo , Estradiol/farmacologia , Inibidores da Síntese de Proteínas/farmacologia , Receptores de Estrogênio/efeitos dos fármacos , Cicloeximida/farmacologia , Dactinomicina/farmacologia , Estradiol/metabolismo , Estrona/metabolismo , Estrona/farmacologia , Meia-Vida , Humanos , Substâncias Intercalantes/farmacologia , Cinética , Peso Molecular , Monoéster Fosfórico Hidrolases/antagonistas & inibidores , Inibidores de Proteínas Quinases , RNA Mensageiro/metabolismo , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Tamoxifeno/análogos & derivados , Tamoxifeno/metabolismo , Trítio , Células Tumorais CultivadasAssuntos
Calcinose/etiologia , Hiperparatireoidismo/complicações , Diálise Renal/efeitos adversos , Adulto , Idoso , Quadril , Humanos , Masculino , Pessoa de Meia-Idade , OmbroRESUMO
Arachidonic, docosahexaenoic and oleic acids were found to produce a dose-dependent cytotoxic effect on MCF-7 cells; palmitic and stearic acids were totally ineffective in this regard suggesting that solely unsaturated fatty acids were able to arrest mammary tumor cell growth. Similarly, only former acids were able to decrease the binding capacity and affinity (increase Kd value) of the cells for 3H-E2 in a dose-dependent manner. In the case of arachidonic acid (the reference fatty acid), this decrease was associated with a slight cleavage of the native 67 KDa estrogen receptor (ER) into 50 and 25-30 KDa peptides as demonstrated by sequential labeling of high-salt cell extracts with 3H-tamoxifen aziridine, specific immunoadsorption with H-222 anti-ER monoclonal antibody, SDS-PAGE and fluorography. Both, modifications in binding characteristics of ER and cleavage of the native 67 KDa receptor were found to be extremely marked when unsaturated fatty acids were directly added to the high-salt cell extracts. This clear influence on the ER structure was reflected on enzyme immunological assay (EIA) by a reduction of ER immunoreactivity of approximately 50% in presence of arachidonic acid. Our observations are discussed in terms of possible interference of unsaturated fatty acids either through transmembrane modulation of phosphokinases and/or phospholipases implicated in ER mechanism of action, or through an intracellular interaction between ER and these acids acting as second messengers in regulation of cellular functions.