RESUMO
Background. Increased oxidative stress is a well described feature of patients in hemodialysis. Their need for multiple blood transfusions and supplemental iron causes a significant iron overload that has recently been associated with increased oxidation of polyunsaturated lipids and accelerated aging due to DNA damage caused by telomere shortening. Methods. A total of 70 patients were evaluated concomitantly, 35 volunteers with ferritin levels below 500 ng/mL (Group A) and 35 volunteers with ferritin levels higher than 500 ng/mL (Group B). A sample of venous blood was taken to extract DNA from leukocytes and to measure relative telomere length by real-time PCR. Results. Patients in Group B had significantly higher plasma TBARS (p = 0.008), carbonyls (p = 0.0004), and urea (p = 0.02) compared with those in Group A. Telomeres were significantly shorter in Group B, 0.66 (SD, 0.051), compared with 0.75 (SD, 0.155) in Group A (p = 0.0017). We observed a statistically significant association between relative telomere length and ferritin levels (r = -0.37, p = 0.001). Relative telomere length was inversely related to time on hemodialysis (r = -0.27, p = 0.02). Conclusions. Our findings demonstrate that iron overload was associated with increased levels of oxidative stress and shorter relative telomere length.
Assuntos
Sobrecarga de Ferro/etiologia , Falência Renal Crônica/complicações , Estresse Oxidativo , Adulto , Senilidade Prematura , Ecocardiografia , Feminino , Ferritinas/análise , Humanos , Sobrecarga de Ferro/metabolismo , Falência Renal Crônica/metabolismo , Falência Renal Crônica/patologia , Leucócitos/citologia , Leucócitos/metabolismo , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Carbonilação Proteica , Reação em Cadeia da Polimerase em Tempo Real , Diálise Renal , Telômero/genética , Encurtamento do Telômero , Ureia/sangueRESUMO
OBJECTIVE: To correlate image parameters in contrast-enhanced digital mammography (CEDM) with blood and lymphatic microvessel density (MVD). METHODS: 18 Breast Imaging-Reporting and Data System (BI-RADS)-4 to BI-RADS-5 patients were subjected to CEDM. Craniocaudal views were acquired, two views (low and high energy) before iodine contrast medium (CM) injection and four views (high energy) 1-5 min afterwards. Processing included registration and two subtraction modalities, traditional single-energy temporal (high-energy) and "dual-energy temporal with a matrix", proposed to improve lesion conspicuity. Images were calibrated into iodine thickness, and iodine uptake, contrast, time-intensity and time-contrast kinetic curves were quantified. Image indicators were compared with MVD evaluated by anti-CD105 and anti-podoplanin (D2-40) immunohistochemistry. RESULTS: 11 lesions were cancerous and 7 were benign. CEDM subtraction strongly increased conspicuity of lesions enhanced by iodine uptake. A strong correlation was observed between lymphatic vessels and blood vessels; all benign lesions had <30 blood microvessels per field, and all cancers had more than this value. MVD showed no correlation with iodine uptake, nor with contrast. The most frequent curve was early uptake followed by plateau for uptake and contrast in benign and malignant lesions. The positive-predictive value of uptake dynamics was 73% and that of contrast was 64%. CONCLUSION: CEDM increased lesion visibility and showed additional features compared with conventional mammography. Lack of correlation between image parameters and MVD is probably due to tumour tissue heterogeneity, mammography projective nature and/or dependence of extracellular iodine irrigation on tissue composition. ADVANCES IN KNOWLEDGE: Quantitative analysis of CEDM images was performed. Image parameters and MVD showed no correlation. Probably, this is indication of the complex dependence of CM perfusion on tumour microenvironment.
Assuntos
Neoplasias da Mama/diagnóstico por imagem , Vasos Linfáticos/patologia , Mamografia/métodos , Microvasos/patologia , Adulto , Idoso , Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/patologia , Meios de Contraste , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
Maintenance of telomere length is one function of human telomerase that is crucial for the survival of cancer cells and cancer progression. Both telomeres and telomerase have been proposed as possible biomarkers of cancer risk and cancer invasiveness; however, their clinical relevance is still under discussion. In order to improve our understanding of the relationship between telomere length and telomerase activity with cancer invasiveness, we studied telomere length as well as telomerase levels, activity, and intracellular localization in breast cancer cell lines with diverse invasive phenotypes. We found an apparently paradoxical coincidence of short telomeres and enhanced telomerase activity in the most invasive breast cancer cell lines. We also observed that hTERT intracellular localization could be correlated with its level of activity. There was no association between human telomerase reverse transcriptase (hTERT) protein expression levels and invasiveness. We propose that simultaneous evaluation of these two biomarkers-telomere length and telomerase activity-could be useful for the assessment of the invasive capacity and aggressiveness of tumor cells from breast cancer patients.
Assuntos
Biomarcadores Tumorais/metabolismo , Telomerase/metabolismo , Encurtamento do Telômero , Telômero/genética , Animais , Western Blotting , Neoplasias da Mama/enzimologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Células HeLa , Humanos , Células MCF-7 , Metaloproteinases da Matriz/metabolismo , Camundongos , Microscopia de Fluorescência , Células NIH 3T3 , Invasividade Neoplásica , Fenótipo , Reação em Cadeia da Polimerase/métodos , Proteína Supressora de Tumor p53/metabolismoRESUMO
BACKGROUND: Recently, a direct correlation with telomere length, proliferative potential and telomerase activity has been found in the process of aging in peripheral blood cells. The objective of the study was to evaluate telomere length and proliferative potential in peripheral blood mononuclear cells (PBMCs) after stimulation with Concanavalin A (ConA) of young adults compared with older adults. METHODS: Blood samples were obtained from 20 healthy young males (20-25 years old) (group Y) and 20 males (60-65 years old) (group O). We compared PBMC proliferation before and after stimulation with ConA. DNA was isolated from cells separated before and after culture with ConA for telomeric measurement by real-time polymerase chain reaction. RESULTS: In vitro stimulation of PBMCs from young subjects induced an increase of telomere length as well as a higher replicative capacity of cell proliferation. Samples from older adults showed higher loss of telomeric DNA (p = 0.03) and higher levels of senescent (≤6.2 kb) telomeric DNA (p = 0.02) and displayed a marked decrease of proliferation capacity. Viability cell counts and CFSE tracking in 72-h-old cell cultures indicated that group O PBMCs (CD8+ and CD4+ T cells) underwent fewer mitotic cycles and had shorter telomeres than group Y (p = 0.04). CONCLUSIONS: Our findings confirm that telomere length in older-age adults is shorter than in younger subjects. After stimulation with ConA, cells are not restored to the previous telomere length and undergo replicative senescence. This is in sharp contrast to the response observed in young adults after ConA stimulation where cells increase in telomere length and replicative capacity. The mechanisms involved in this phenomenon are not yet clear and merit further investigation.
Assuntos
Envelhecimento/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Concanavalina A/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Homeostase do Telômero/efeitos dos fármacos , Adulto , Idoso , Envelhecimento/fisiologia , Células Cultivadas , Humanos , Leucócitos Mononucleares/fisiologia , Masculino , Pessoa de Meia-Idade , Homeostase do Telômero/fisiologia , Adulto JovemRESUMO
A common causative agent for uterine cervical cancer is the human papillomavirus type 18 (HPV-18) which has three phylogenic variants: Asian-Amerindian, European, and African. Each variant shows significant molecular differences in the E6 gene. E6 oncoprotein is a negative regulator of tumor suppressor protein p53, hence, this oncoprotein indirectly regulates the expression of tumor-suppressor p14(ARF) . p14(ARF) and p16(INK4A) genes are overexpressed in--and have been proposed as markers for--HPV-related cervical cancer. In order to dissect the role of E6 on the regulation of p14(ARF) expression, separating it from that of other intervening factors, transfection of E6 variants to MCF-7 cells was performed, assessing cDNA transcript levels by RT-PCR, whereas p14(ARF) and p53 expression were evaluated by immunocytochemistry and Western blot. E6 transfected cells differentially expressed transcripts of two molecular forms: E6 and E6*. The ratio of these two forms varied with the transfected E6 variant. With the Asian-Amerindian variant, the ratio was E6 > E6*, whereas with the European and the African the ratio was E6* > E6. As expected with the E6* construct, E6* transcripts were solely observed. In addition, when E6 > E6* and p53 expression was low, p14(ARF) was high and when E6* > E6 and p53 expression was high, p14(ARF) was low. In conclusion, each E6 variant distinctively affects p53 levels and consequently p14(ARF) expression, finding that could be related with the differences in oncogenic effect of infection with the diverse high-risk HPV variants.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno , Papillomavirus Humano 18/fisiologia , Proteínas Oncogênicas Virais/genética , Proteínas Oncogênicas Virais/metabolismo , Proteína Supressora de Tumor p14ARF/biossíntese , Proteína Supressora de Tumor p53/biossíntese , Western Blotting , Linhagem Celular , Feminino , Perfilação da Expressão Gênica , Humanos , Imuno-Histoquímica , Reação em Cadeia da Polimerase em Tempo RealRESUMO
The female reproductive system (FRS) has a great capacity for regeneration. The existence of somatic stem cells (SSC) that are likely to reside in distinct tissue compartments of the FRS is anticipated. Normal SSC are capable of regenerating themselves, produce a progeny of cells that differentiate and maintain tissue architecture and functional characteristics, and respond to homeostatic controls. Among those SSC of the FRS that have been identified are: a) undifferentiated cells capable of differentiating into thecal cells and synthesizing hormones upon transplantation, b) ovarian surface epithelium stem cells, mitotically responsive to ovulation, c) uterine endometrial and myometrial cells, as clonogenic epithelial and stromal cells, and d) epithelial and mesenchymal cells with self-renewal capacity and multipotential from cervical tissues. Importantly, these cells are believed to significantly contribute to the development of different pathologies and tumors of the FRS.It is now widely accepted that cancer stem cells (CSC) are at the origin of many tumors. They are capable of regenerating themselves, produce a progeny that will differentiate aberrantly and do not respond adequately to homeostatic controls. Several cell surface antigens such as CD44, CD117, CD133 and MYD88 have been used to isolate ovarian cancer stem cells. Clonogenic epithelial and stromal endometrial and myometrial cells have been found in normal and cancer tissues, as side population, label-retaining cells, and CD146/PDGF-R beta-positive cells with stem-like features. In summary, here we describe a number of studies supporting the existence of somatic stem cells in the normal tissues and cancer stem cells in tumors of the human female reproductive system.
Assuntos
Neoplasias dos Genitais Femininos/patologia , Genitália Feminina/citologia , Células-Tronco Neoplásicas/patologia , Células-Tronco/citologia , Biomarcadores/metabolismo , Biomarcadores Tumorais/metabolismo , Diferenciação Celular , Proliferação de Células , Feminino , Neoplasias dos Genitais Femininos/metabolismo , Genitália Feminina/metabolismo , Humanos , Células-Tronco Neoplásicas/metabolismo , Células-Tronco/metabolismoRESUMO
During carcinogenesis it is known that growth factors and cytokines from stromal and inflammatory cells from the microenvironment promote angiogenesis and lymphangiogenesis. However, the participation of macrophages and mast cells in these processes is not well understood. The aim of this study was to evaluate the relationship between mast cell and macrophage density with blood and lymphatic vessels in various stages of carcinoma of the uterine cervix. Tissue sections from archival paraffin-embedded samples from cases with cervical intraepithelial neoplasias (CIN) 1, 2, 3, carcinoma in situ, and invasive carcinoma were used. Immunohistochemical staining was done using the following antibodies: anti-LYVE-1; anti-CD31; anti-CD68, and anti-tryptase. Our results showed a significant increase in the number of macrophages in carcinoma in situ, a correlation between lymphatic vessels and macrophages in premalignant lesions CIN 2, and a correlation between mast cells and blood vessels in both CIN 2 and carcinoma in situ. In conclusion, our data underscore the importance of the recruitment of macrophages and mast cells in the development of tumor-associated blood and lymphatic capillaries.
Assuntos
Carcinoma in Situ/imunologia , Linfangiogênese/imunologia , Macrófagos/imunologia , Mastócitos/imunologia , Neovascularização Patológica/imunologia , Displasia do Colo do Útero/imunologia , Neoplasias do Colo do Útero/imunologia , Neoplasias do Colo do Útero/patologia , Antígenos CD , Antígenos de Diferenciação Mielomonocítica , Carcinoma in Situ/patologia , Estudos de Casos e Controles , Feminino , Humanos , Macrófagos/metabolismo , Mastócitos/metabolismo , Neoplasias do Colo do Útero/irrigação sanguínea , Displasia do Colo do Útero/patologiaRESUMO
Small RNAs belong to a newly discovered strain of molecules. These molecules are composed of double strand RNA comprised by just about 19-31 nucleotides. They have two main characteristics that make them unique. Firstly, they are noncoding for proteins and second they interfere post-transcriptional with mRNA. This interfering action is the distinguishing hallmark, therefore known as interfering RNA or RNAi. There are three main subclasses of which micro-RNA and siRNA are the most widely studied. Interference RNAs participate in a myriad of cellular functions mainly through modulation of genetic expression. Due to these capabilities it has been used as therapeutic weapon in a number of diseases including cancer. It is known that both miRNA and siRNA participate in carcinogenesis, either inhibiting suppressor genes, or stimulating oncogenes. It has been demonstrated that manipulating small interfering RNAs in cell lines and animal models, the malignant and metastatic phenotype can be reversed. Up to now a few clinical trials using RNAi as a therapeutic agent have demonstrated some success and feasibility. It is forseeable that in the near future cancer treatment with small RNAs will be widely applicable, once the many constrains for its systemic application are surpassed.
Assuntos
Regulação Neoplásica da Expressão Gênica/genética , Terapia Genética/métodos , MicroRNAs/genética , Neoplasias/genética , Interferência de RNA , RNA Mensageiro/genética , RNA Interferente Pequeno/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/patologia , Transformação Celular Neoplásica/genética , Ensaios Clínicos como Assunto , Sistemas de Liberação de Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Estudos de Viabilidade , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Genes Supressores de Tumor , Vetores Genéticos/uso terapêutico , Humanos , Masculino , MicroRNAs/biossíntese , Neoplasias/tratamento farmacológico , Neoplasias/terapia , Neoplasias/virologia , Oncogenes , RNA Mensageiro/antagonistas & inibidores , RNA Neoplásico/antagonistas & inibidores , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , RNA Interferente Pequeno/genéticaRESUMO
The Papanicolaou test (Pap) has been responsible for a significant reduction of cervical cancer-related morbimortality. In order to increase its sensitivity and specificity new markers have been studied and incorporated to cytological and histological methods for diagnosis for cervical cancer, such as p16INK4A that has been considered the immunocytochemical marker of choice for detection of HPV related cancers. We considered that p14ARF could be a complementary marker in order to improve the accuracy of cytological diagnosis because its genetic proximity to p16INK4A. We performed a systematic analysis of several putative cervical cancer markers in order to evaluate their performance in the detection of malignancy, in comparison with p16INK4A and p14ARF, using immunocytochemistry (ICC), immunofluorescence (IF) and Western blot analyses. Most markers were non-specific and could not discriminate HPV infected cancer cell lines from other non HPV malignant. In contrast, nuclear co-expression of p16INK4A and p14ARF was observed only in HPV-transformed cancer cell lines. Notably, in C-33A cervical cancer cells (HPV negative), p14ARF was present in the nucleoli, but p16INK4A was conspicuously absent from the nuclei of these cells. We conclude that both markers; p16INK4A and p14ARF are complementary and should be evaluated jointly in order to improve the accuracy of cytological diagnosis of cervical cancer.
Assuntos
Núcleo Celular/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Papillomaviridae/metabolismo , Proteína Supressora de Tumor p14ARF/metabolismo , Neoplasias do Colo do Útero/metabolismo , Catepsinas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Inibidor p16 de Quinase Dependente de Ciclina/genética , Fator de Transcrição E2F1/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica , Células HeLa , Humanos , Metaloproteinases da Matriz/metabolismo , Proteínas Oncogênicas Virais/genética , Proteínas Oncogênicas Virais/metabolismo , Papillomaviridae/genética , Proteína do Retinoblastoma/genética , Proteína do Retinoblastoma/metabolismo , Proteína Supressora de Tumor p14ARF/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/virologiaRESUMO
When the first preventive HPV vaccine became available in 2006, it drew both enthusiasm and multiple ethical problems. In the case of HPV vaccination, there is a clear conflict between the scientific data that claim a definitive advantage for preventing HPV infection in the exposed population and the ethical and moral issues resulting from a compulsory program. Despite the evident success of routine and compulsory vaccination in young women, there is increasing concern about safety, efficacy, and equity of the vaccine and to close the knowledge "gaps" about HPV infection and consequent health outcomes. Some of these fears are expressed particularly in conservative groups that link these arguments to those of religious and moral issues contending that HPV vaccination is an indirect license for liberal sexual activity in youths, resulting in promiscuity and/or less participation in cervical cancer screening. It has been well demonstrated that HPV infection can lead to harm through the induction of premalignant and cancerous lesions. Therefore, any proven method for preventing infection, such as HPV vaccines, should be used in persons at risk. These policies, however, should be strictly linked to cervical cancer screening programs.
Assuntos
Vacinas contra Papillomavirus/imunologia , Vacinação/ética , Adolescente , Criança , Feminino , Humanos , Neoplasias do Colo do Útero/prevenção & controle , Vacinação/métodosRESUMO
Invasion and metastasis are the most important events in cancer progression. In these two phases, several molecules are implicated and have been long associated with several forms of cancer. Proteases play a critical role not only in tumor cell invasion, but also in the earliest stages of carcinogenesis and its associated changes: angiogenesis and metastasis. Aside from their ability to degrade the extracellular matrix, facilitate invasion and metastasis, proteases target a great variety of substrates that favor or inhibit cancer progression: b-FGF, HGF, VEGF, cell death receptors, cistatin-C, galectin, procollagen, and other proteases. Proteases are also signaling molecules that modulate other molecules by underlying pathways in addition to their degradative role. Proteases form interconnected cascades, circuits and networks that bring about the tumor's potential for malignancy. Although, proteases are regulated by diverse molecules, it is known that tumoral and stromal cells secrete several biological molecules, including cytokines and chemokines that directly or indirectly regulate the protease-expression within the tumor's microenvironment. The present review briefly summarizes some of the major aspects associated with the role of proteases in cancer progression.
Assuntos
Neoplasias/enzimologia , Peptídeo Hidrolases/fisiologia , Animais , Membrana Basal/fisiologia , Matriz Extracelular/fisiologia , Humanos , Neovascularização PatológicaRESUMO
La invasión y la metástasis son los eventos más importantes en la progresión del cáncer, en los cuales están implicadas muchas moléculas, entre ellas, las proteasas. Éstas desempeñan un papel importante en etapas tempranas de la carcinogénesis, en la invasión, en fenómenos asociados como la angiogénesis y en la metástasis, principalmente por su capacidad para degradar componentes de la matriz extracelular, aunque sus sustratos son de naturaleza diversa: citocinas, quimiocinas, factores de crecimiento (b- FGF, HGF, VEGF) y de muerte celular, cistatina-C, galectina, procolágena y otras proteasas, que pueden favorecer o inhibir la progresión neoplásica. Las proteasas son también moléculas de señalización que modulan a otras moléculas; forman cascadas, circuitos e incluso redes, que en conjunto determinan parte del potencial maligno. Se sabe que tanto la célula tumoral como las del estroma secretan diversos factores que regulan directa e indirectamente la expresión de proteasas en el microambiente tumoral. Esta revisión proporciona un panorama breve y actualizado sobre la participación de las proteasas en la progresión neoplásica.
Invasion and metastasis are the most important events in cancer progression. In these two phases, several molecules are implicated and have been long associated with several forms of cancer. Proteases play a critical role not only in tumor cell invasion, but also in the earliest stages of carcinogenesis and its associated changes: angiogenesis and metastasis. Aside from their ability to degrade the extracellular matrix, facilitate invasion and metastasis, proteases target a great variety of substrates that favor or inhibit cancer progression: b-FGF, HGF, VEGF, cell death receptors, cistatin-C, galectin, procollagen, and other proteases. Proteases are also signaling molecules that modulate other molecules by underlying pathways in addition to their degradative role. Proteases form interconnected cascades, circuits and networks that bring about the tumor's potential for malignancy. Although, proteases are regulated by diverse molecules, it is known that tumoral and stromal cells secrete several biological molecules, including cytokines and chemokines that directly or indirectly regulate the protease-expression within the tumor's microenvironment. The present review briefly summarizes some of the major aspects associated with the role of proteases in cancer progression.
Assuntos
Humanos , Animais , Neoplasias/enzimologia , Peptídeo Hidrolases/fisiologia , Matriz Extracelular/fisiologia , Membrana Basal/fisiologia , Neovascularização PatológicaRESUMO
It is well-known that there are different tumor-type-dependent metastatic patterns. For example, in carcinomas metastatic spread is preferentially via the lymphatic system by which they reach regional lymph nodes through pre-existent afferent lymph vessels and/or newly formed lymph capillaries; while in sarcomas the favored pathway is through bloodvessels. These metastatic patterns have been used for many years by clinicians and surgeons for staging and tumor resection, particularly in the case of breast cancer. Recently this knowledge has been applied to detection and resection of sentinel lymph nodes. The lymphatic system drains the interstitial fluid from tissues and reincorporates it into the blood flow; in addition, it forms part of the host's immune defense and in pathological conditions, induces different types of lymph edema and participates in tumor invasion and metastasis. Although, the study of lymphangiogenesis was stagnated for several decades, it was not until a few years ago that biomolecular mechanisms were discovered and many specific markers are now in use to study the process of tumor dissemination and metastasis. There is a tendency to utilize molecular knowledge in clinical settings for grading and estimating prognostic significance of tumors as well as to develop specific therapeutic strategies.
Assuntos
Metástase Linfática , Neoplasias/patologia , Humanos , Sistema Linfático/anatomia & histologia , Sistema Linfático/fisiologiaRESUMO
Es bien sabido que existen diferentes patrones de metástasis dependiendo del tipo tumoral. Por ejemplo, la diseminación metastásica de los carcinomas es vía linfática preferencialmente, las células neoplásicas llegan a los ganglios linfáticos regionales a través de vasos linfáticos aferentes preexistentes o capilares linfáticos de nueva formación; en cambio, en los sarcomas la vía principal es a través de los vasos sanguíneos. Estos patrones metastásicos han sido utilizados durante muchos años por los clínicos y cirujanos para la etapificación y resección tumoral, particularmente en cáncer de mama. Recientemente este conocimiento ha sido aplicado para la detección y resección del ganglio centinela. El sistema linfático drena el líquido intersticial de los tejidos y lo reincorpora al sistema sanguíneo; además, forma parte de la defensa inmune del huésped y en condiciones patológicas induce diferentes tipos de linfedema y participa en la invasión y metástasis. El estudio de la linfangiogénesis permaneció aletargado por muchas décadas y no es sino hasta los últimos años que se han descrito mecanismos biomoleculares y marcadores específicos, los cuales actualmente se están utilizando para estudiar el proceso de diseminación tumoral y metástasis. Existe una tendencia hacia la aplicación clínica de este conocimiento molecular en la clínica para estimar el significado pronóstico de los tumores, así como para desarrollar estrategias terapéuticas específicas.
It is well-known that there are different tumor-type-dependent metastatic patterns. For example, in carcinomas metastatic spread is preferentially via the lymphatic system by which they reach regional lymph nodes through pre-existent afferent lymph vessels and/or newly formed lymph capillaries; while in sarcomas the favored pathway is through bloodvessels. These metastatic patterns have been used for many years by clinicians and surgeons for staging and tumor resection, particularly in the case of breast cancer. Recently this knowledge has been applied to detection and resection of sentinel lymph nodes. The lymphatic system drains the interstitial fluid from tissues and reincorporates it into the blood flow; in addition, it forms part of the host's immune defense and in pathological conditions, induces different types of lymph edema and participates in tumor invasion and metastasis. Although, the study of lymphangiogenesis was stagnated for several decades, it was not until a few years ago that biomolecular mechanisms were discovered and many specific markers are now in use to study the process of tumor dissemination and metastasis. There is a tendency to utilize molecular knowledge in clinical settings for grading and estimating prognostic significance of tumors as well as to develop specific therapeutic strategies.
Assuntos
Humanos , Metástase Linfática , Neoplasias/patologia , Sistema Linfático/anatomia & histologia , Sistema Linfático/fisiologiaRESUMO
Expression of estrogen receptors (ER) is clinically relevant in designing therapeutic strategies. The relative importance of the two types of estrogen receptors (ER-alpha and ER-beta) in human breast cancers in pre- and post-menopausal women has not been properly defined. To determine the possible association between the expression of estrogen receptor and serum estradiol levels in pre- and post-menopausal women with breast cancer. 44 patients with invasive ductal carcinoma of the breast were studied and a breast tissue biopsy was taken. ER-alpha and ER-beta were detected by immunocytochemistry. Serum levels of estradiol and estrone were measured by radioimmunoassay and FSH was measured using IRMA. We studied 21 pre- and 23 post-menopausal women with breast carcinoma. Examining the number of cases with tumors positive for ER, we found no differences in the frequency of ER-alpha between pre- and post-menopausal women, but ER-beta decreased marginally after menopause (p < 0.051). In cases with tumors positive for ER, the proportion of cells positive for ER-alpha was similar post-menopausally (53.95%) and pre-menopausally (57.21%), but for ER-beta the number of positive cells decreased significantly after menopause (p < 0.051). In pre-menopausal women there was a correlation between serum estradiol levels and ER-beta; in post-menopausal women there was a correlation between serum FSH levels and ER-alpha. These results indicate that estradiol levels in women with mammary carcinoma are related to ER-beta expression in the breast tumor tissue.
Assuntos
Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/metabolismo , Receptor alfa de Estrogênio/biossíntese , Receptor beta de Estrogênio/biossíntese , Pós-Menopausa/metabolismo , Pré-Menopausa/metabolismo , Adulto , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , RadioimunoensaioRESUMO
Combined chemotherapy is used for the treatment of a number of malignancies such as breast cancer. The target of these antineoplastic agents is nuclear DNA, although it is not restricted to malignant cells. The aim of the present study was to assess DNA damage in peripheral blood lymphocytes (PBLs) of breast cancer patients subjected to combined adjuvant chemotherapy (5-fluorouracil, epirubicin and cyclophosphamide, FEC), using a modified comet assay to detect DNA single-strand breaks (SSB) and double-strand breaks (DSB). Forty-one female patients with advanced breast cancer before and after chemotherapy and 60 healthy females participated in the study. Alkaline and neutral comet assays were performed in PBLs according to a standard protocol, and DNA tail moment was measured by a computer-based image analysis system. Breast cancer patients before treatment had higher increased background levels of SSB and DSB as compared to healthy women. During treatment, a significant increase in DNA damage was observed after the 2nd cycle, which persisted until the end of treatment. Eighty days after the end of treatment the percentage of PBLs with SSB and DSB remained elevated, but the magnitude of DNA damage (tail moment) returned to baseline levels. There was no correlation between PBL DNA damage and response to chemotherapy. DNA-SSB and DSB in PBLs are present in cancer patients before treatment and increase significantly after combined chemotherapy. No correlation with response to adjuvant chemotherapy was found. Biomonitoring DNA damage in PBLs of cancer patients could help prevent secondary effects and the potential risks of developing secondary cancers.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Carcinoma Ductal de Mama/tratamento farmacológico , Carcinoma Ductal de Mama/genética , Dano ao DNA , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Ensaio Cometa , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Epirubicina/administração & dosagem , Epirubicina/efeitos adversos , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Humanos , Linfócitos/ultraestrutura , Pessoa de Meia-IdadeRESUMO
BACKGROUND: The mechanism for maintaining telomere integrity is controlled by telomerase, a ribonucleoprotein enzyme that specifically restores telomere sequences, lost during replication by means of an intrinsic RNA component as a template for polymerization. Among the telomerase subunits, hTERT (human telomerase reverse transcriptase) is expressed concomitantly with the activation of telomerase. The role of estrogens and their receptors in the transcriptional regulation of hTERT has been demonstrated. The current study determines the possible association between telomerase activity, the expression of both molecular forms of estrogen receptor (ERalpha and ERbeta) and the protein bcl-2, and their relative associations with clinical parameters. METHODS: Tissue samples from 44 patients with breast cancer were used to assess telomerase activity using the TRAP method and the expression of ERalpha, ERbeta and bcl-2 by means of immunocytochemical techniques. RESULTS: Telomerase activity was detected in 59% of the 44 breast tumors examined. Telomerase activity ranged from 0 to 49.93 units of total product generated (TPG). A correlation was found between telomerase activity and differentiation grade (p = 0.03). The only significant independent marker of response to treatment was clinical stage. We found differences between the frequency of expression of ERalpha (88%) and ERbeta (36%) (p = 0.007); bcl-2 was expressed in 79.5% of invasive breast carcinomas. We also found a significant correlation between low levels of telomerase activity and a lack of ERbeta expression (p = 0.03). CONCLUSION: Lower telomerase activity was found among tumors that did not express estrogen receptor beta. This is the first published study demonstrating that the absence of expression of ERbeta is associated with low levels of telomerase activity.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Telomerase/metabolismo , Resultado do Tratamento , Adulto , Idoso , Carcinoma/tratamento farmacológico , Carcinoma/metabolismo , Ciclofosfamida/uso terapêutico , Epirubicina/uso terapêutico , Feminino , Fluoruracila/uso terapêutico , Células HeLa/metabolismo , Humanos , Pessoa de Meia-IdadeRESUMO
BACKGROUND: The development of resistance to cytotoxic chemotherapy continues to be a major obstacle for successful anticancer therapy. It has been shown that cells exposed to toxic concentrations of commonly used cancer chemotherapy agents develop DNA hypermethylation. Hence, demethylating agents could play a role in overcoming drug resistance. METHODS: MCF-7 cells were rendered adriamycin-resistant by weekly treatment with adriamycin. Wild-type and the resulting MCF-7/Adr cells were analyzed for global DNA methylation. DNA methyltransferase activity and DNA methyltransferase (dnmt) gene expression were also determined. MCF-7/Adr cells were then subjected to antisense targeting of dnmt1, -3a, and -b genes and to treatment with the DNA methylation inhibitor hydralazine to investigate whether DNA demethylation restores sensitivity to adriamycin. RESULTS: MCF-7/Adr cells exhibited the multi-drug resistant phenotype as demonstrated by adriamycin resistance, mdr1 gene over-expression, decreased intracellular accumulation of adriamycin, and cross-resistance to paclitaxel. The mdr phenotype was accompanied by global DNA hypermethylation, over-expression of dnmt genes, and increased DNA methyltransferase activity as compared with wild-type MCF-7 cells. DNA demethylation through antisense targeting of dnmts or hydralazine restored adriamycin sensitivity of MCF-7/Adr cells to a greater extent than verapamil, a known inhibitor of mdr protein, suggesting that DNA demethylation interferes with the epigenetic reprogramming that participates in the drug-resistant phenotype. CONCLUSION: We provide evidence that DNA hypermethylation is at least partly responsible for development of the multidrug-resistant phenotype in the MCF-7/Adr model and that hydralazine, a known DNA demethylating agent, can revert the resistant phenotype.
RESUMO
Leukemia-associated fusion genes are detected in a significant proportion of newly diagnosed cases, where genes encoding transcription factors are usually found at one of the breakpoints. Activated fusion proteins such as Pml-Raralpha have been shown to inhibit cellular differentiation by recruitment of nuclear corepressor complexes, which maintain local histone deacetylase (HDAC) in a variety of hematologic lineage-specific gene promoters. This HDAC-dependent transcriptional repression appears as a common pathway in the development of leukemia and could constitute an important target for new therapeutic agents. Alternatively, the Bcr-Abl oncoprotein shows high tyrosine kinase activity and deregulates signal transduction pathways normally involved in both apoptosis and proliferation. This aberrant activity is affected by signal transduction inhibitors (STIs), which block or prevent the oncogenic pathway. In this review, we shed some light on our understanding of both the reversible transcriptional repression controlled by HDAC and the deregulated Bcr-Abl signal transduction pathway. In addition, the administration of low molecular weight drugs for human leukemia treatment based on this knowledge brings about a significant long-term clinical remission and an acceptable risk of toxic effects that should increase the cure rate.