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1.
Braz J Med Biol Res ; 53(11): e10067, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33053110

RESUMO

RU486 (mifepristone), a glucocorticoid and progesterone receptor antagonist, has been reported to exert antiproliferative effects on tumor cells. Experiments were performed to analyze the effects of RU486 on the proliferation of the human neuroblastoma, both in vitro and in vivo, using the human neuroblastoma SK-N-SH cell line. The exposure in vitro of SK-N-SH cells to RU486 revealed a dose-dependent inhibition of 3H-thymidine incorporation due to a rapid but persistent inhibition of MAPKinase activity and ERK phosphorylation. A significant decrease of SK-N-SH cell number was evident after 3, 6, and 9 days of treatment (up to 40% inhibition), without evident cell death. The inhibitory effect exerted by RU486 was not reversed by the treatment of the cells with dexamethasone or progesterone. Moreover, RU486 induced a shift in SK-N-SH cell phenotypes, with an almost complete disappearance of the neuronal-like and a prevalence of the epithelial-like cell subtypes. Finally, the treatment with RU486 of nude mice carrying a SK-N-SH cell xenograft induced a strong inhibition (up to 80%) of tumor growth. These results indicated a clear effect of RU486 on the growth of SK-N-SH neuroblastoma cells that does not seem to be mediated through the classical steroid receptors. RU486 acted mainly on the more aggressive component of the SK-N-SH cell line and its effect in vivo was achieved at a concentration already used to inhibit oocyte implantation.


Assuntos
Neuroblastoma , Animais , Glucocorticoides , Humanos , Camundongos , Camundongos Nus , Mifepristona/farmacologia , Neuroblastoma/tratamento farmacológico , Progesterona
2.
Braz. j. med. biol. res ; 53(11): e10067, 2020. graf
Artigo em Inglês | LILACS, Coleciona SUS | ID: biblio-1132493

RESUMO

RU486 (mifepristone), a glucocorticoid and progesterone receptor antagonist, has been reported to exert antiproliferative effects on tumor cells. Experiments were performed to analyze the effects of RU486 on the proliferation of the human neuroblastoma, both in vitro and in vivo, using the human neuroblastoma SK-N-SH cell line. The exposure in vitro of SK-N-SH cells to RU486 revealed a dose-dependent inhibition of 3H-thymidine incorporation due to a rapid but persistent inhibition of MAPKinase activity and ERK phosphorylation. A significant decrease of SK-N-SH cell number was evident after 3, 6, and 9 days of treatment (up to 40% inhibition), without evident cell death. The inhibitory effect exerted by RU486 was not reversed by the treatment of the cells with dexamethasone or progesterone. Moreover, RU486 induced a shift in SK-N-SH cell phenotypes, with an almost complete disappearance of the neuronal-like and a prevalence of the epithelial-like cell subtypes. Finally, the treatment with RU486 of nude mice carrying a SK-N-SH cell xenograft induced a strong inhibition (up to 80%) of tumor growth. These results indicated a clear effect of RU486 on the growth of SK-N-SH neuroblastoma cells that does not seem to be mediated through the classical steroid receptors. RU486 acted mainly on the more aggressive component of the SK-N-SH cell line and its effect in vivo was achieved at a concentration already used to inhibit oocyte implantation.


Assuntos
Humanos , Animais , Coelhos , Neuroblastoma/tratamento farmacológico , Progesterona , Mifepristona/farmacologia , Glucocorticoides , Camundongos Nus
3.
Appl Radiat Isot ; 106: 129-33, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26242561

RESUMO

This paper reports the preliminary results obtained by Electron Paramagnetic Resonance (EPR) measurements on films of IRGANOX® 1076 phenols with and without low content (5% by weight) of gadolinium oxide (Gd2O3) exposed in the thermal column of the Triga Mark II reactor of LENA (Laboratorio Energia Nucleare Applicata) of Pavia (Italy). Thanks to their size, the phenolic films here presented are good devices for the dosimetry of beams with high dose gradient and which require accurate knowledge of the precise dose delivered. The dependence of EPR signal as function of neutron dose was investigated in the fluence range between 10(11) cm(-2) and 10(14) cm(-2). Linearity of EPR response was found and the signal was compared with that of commercial alanine films. Our analysis showed that gadolinium oxide (5% by weight) can enhance the thermal neutron sensitivity more than 18 times. Irradiated dosimetric films of phenolic compound exhibited EPR signal fading of about 4% after 10 days from irradiation.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Nêutrons , Fenóis/química , Calibragem
4.
Radiat Prot Dosimetry ; 159(1-4): 233-6, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24795394

RESUMO

This paper continues analyses on organic compounds for application in neutron dosimetry performed through electron spin resonance (ESR). Here, the authors present the results obtained by ESR measurements of a blend of ammonium tartrate dosemeters and gadolinium oxide (5 % by weight). The choice of low amount of Gd is due to the need of improving neutron sensitivity while not significantly influencing tissue equivalence. A study of the effect of gadolinium presence on tissue equivalence was carried out. The experiments show that the neutron sensitivity is enhanced by more than an order of magnitude even with this small additive content. Monte Carlo simulations on the increment of energy release due to gadolinium presence were carried, and the results were in good agreement with the experimental data.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Gadolínio/efeitos da radiação , Nêutrons , Radiometria/métodos , Tartaratos/efeitos da radiação , Gadolínio/química , Método de Monte Carlo , Doses de Radiação , Tartaratos/química
5.
Radiat Prot Dosimetry ; 161(1-4): 383-6, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24262924

RESUMO

This paper reports on results obtained by electron paramagnetic resonance (EPR) measurements and Monte Carlo (MC) simulation on a blend of alanine added with low content of gadolinium oxide (5 % by weight) to improve the sensitivity to thermal neutron without excessively affecting tissue equivalence. The sensitivity is enhanced by this doping procedure of more an order of magnitude. The results are compared with those obtained with the addition of boric acid (50 % by weight) where boron is in its natural isotopic composition in order to produce low-cost EPR dosemeters. The gadolinium addition influences neutron sensitivity more than the boron addition. The presence of additives does not substantially change the fading of the EPR signal induced by neutrons. The MC simulations agree the experimental results in case of gadolinium addition.


Assuntos
Alanina/química , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Gadolínio/química , Nêutrons , Radiometria/métodos , Ácidos Bóricos/química , Espectroscopia de Ressonância de Spin Eletrônica/instrumentação , Isótopos , Método de Monte Carlo , Doses de Radiação , Radiometria/instrumentação
6.
J Endocrinol Invest ; 36(9): 775-80, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23765505

RESUMO

Adrenal glucocorticoids (Gc) are among the most significant hormones in the mammalian organisms; these steroids may reach and penetrate all tissues where they interact with cytoplasmic/nuclear receptors, through which they exert multiple and very multifaceted actions. The effects of physiological concentrations of Gc on brain functions have not been completely clarified, even though Gc are recognized to influence behavioral responses, emotions, cognitive processes and to take part in the neuroendocrine control of body homeostasis. Developmental programming effects of Gc in animal models and humans have been proposed. Actually, pre-natal stress, or exposure to high Gc levels, would somehow affect neuronal developmental events in some structure and this can lead to central nervous system altered functions, as the impairment of neuroendocrine activities, cognitive processes, sleep and mood disorders. Interestingly, it has been observed that these abnormalities may not be limited to the first directly exposed individuals but transmissible across generations. The establishment of animal models with localized pre-natal glucocorticoid receptors deficiency led to the accumulation of data on the possible roles of these hormones on development of the central and peripheral nervous system. The most recent findings on the effects of Gc on neuroblast development, with particular attention to neuronal migration, will be presented.


Assuntos
Glucocorticoides/fisiologia , Sistema Nervoso/embriologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/fisiologia , Proteínas de Ligação a Calmodulina/genética , Movimento Celular , Sistema Nervoso Central/embriologia , Humanos , Erros Inatos do Metabolismo/fisiopatologia , Sistema Nervoso/efeitos dos fármacos , Neurônios/fisiologia , Sistema Nervoso Periférico/embriologia , Receptores de Glucocorticoides/biossíntese , Receptores de Glucocorticoides/deficiência
7.
J Phys Chem A ; 117(16): 3304-18, 2013 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-23521082

RESUMO

A matrix EPR spectroscopy study of the low temperature γ radiolysis of precipitated (Zeosil) and mesoporous high surface silica has afforded evidence of the formation of trapped H-atoms, H-atom centers, siloxy radicals ≡Si-O(•), anomalous silyl peroxy radicals ≡Si-OO(•) with reduced g tensor anisotropy, siloxy radical-cations (≡Si-O-Si≡)(+•), E' centers, and two species from Ge impurity. Coordination of peroxyl radicals with diamagnetic ≡Si(+) centers is proposed and tested by DFT computations in order to justify the observed g tensor. Coordination of H-atoms to ≡Si(+) centers is also proposed for the structure of the H-atom centers as an alternative model not requiring the intervention of Ge, Sn, or CO impurities. The DFT method has been employed to assess the electronic structure of siloxy radical-cations and its similarity with that of the carbon radical-cation analogues; the results have prompted a revision of the structures proposed in the literature for ST1 and ST2 centers. The comparison between the two types of silica has afforded evidence of different radiolysis mechanisms leading to a greater yield of trapped H-atoms and H-atom centers in zeosil silica, which is reckoned with the 4-fold greater concentration of silanol groups. Parallel radiolysis experiments carried out by using both types of silica with polybutadiene oligomers as adsorbate have afforded evidence of free valence and energy migration phenomena leading to irreversible linking of polybutadiene chains onto silica. Reaction mechanisms are proposed based on the detection of SiO2-bonded free radicals whose structure has been defined by EPR.

8.
Eur J Cancer ; 48(5): 642-7, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21757335

RESUMO

AIMS: Triple-negative breast cancers (TNBCs) lack expression of oestrogen, progesterone, and Human Epidermal Growth Factor 2 receptors. The NEMESI study described current Italian treatment practices in patients with operable, early-stage breast cancer (EBC). PATIENTS AND METHODS: Retrospective, observational study involving 63 Italian oncology centres. Eligible patients were aged ≥ 18 years with EBC (stage I-II) who had undergone surgery, received ≥ 1 cycle of adjuvant chemotherapy and/or adjuvant hormonal therapy and attended an oncology centre between 1 January 2008 and 30 June 2008. This subanalysis focused on patients with TNBC. Variables evaluated included: demographic data/clinical characteristics; tumour characteristics; adjuvant therapy; compliance to chemotherapy. Continuous variables were summarised using descriptive statistics. RESULTS: Of 1894 patients in the NEMESI study, 185 patients (9.8%) had TNBC. At diagnosis, 98 patients were aged 50-70 years and 114 were post-menopausal. Tumours were subcategorised as pT1mic/pT1a/pT1b/pT1c in 108 patients and pT2/pT3/pT4b in 77 patients. Mean tumour size was 2.1cm, tumours were highly undifferentiated in 144 patients and 128 patients were pNO. 179 patients received adjuvant chemotherapy; anthracyclines with or without taxanes were commonly used. 145 patients received radiotherapy. CONCLUSIONS: Adherence of Italian clinical practice to International Guidelines in the management of early-stage TNBC is satisfactory.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/terapia , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/patologia , Quimioterapia Adjuvante , Terapia Combinada , Feminino , Humanos , Itália , Pessoa de Meia-Idade , Radioterapia Adjuvante , Receptor ErbB-2/metabolismo , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Estudos Retrospectivos
9.
Ann Oncol ; 21(7): 1515-1522, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20032123

RESUMO

BACKGROUND: Concomitant chemoradiotherapy (CT/RT) is the standard treatment of locally advanced squamous cell carcinoma of the head and neck (SCCHN). We evaluated the efficacy of induction docetaxel (Taxotere), cisplatin, and 5-fluorouracil (TPF) before CT/RT versus CT/RT alone. PATIENTS AND METHODS: Patients with stage III-IVM0 SCCHN, Eastern Cooperative Oncology Group performance status of zero to one, were randomly assigned to receive CT/RT alone (arm A: two cycles of cisplatin 20 mg/m(2), days1-4, plus 5-fluorouracil 800 mg/m(2)/day 96 h continuous infusion, during weeks 1 and 6 of radiotherapy) or three cycles of TPF (arm B: docetaxel 75 mg/m(2) and cisplatin 80 mg/m(2), day 1, and 5-fluorouracil 800 mg/m(2)/day 96 h continuous infusion, every 3 weeks) followed by the same CT/RT. The primary end point was the rate of radiologic complete response (CR) at 6-8 weeks after the end of CT/RT. RESULTS: A total of 101 patients were randomly allocated to the study (51 arm A; 50 arm B). CR rates were 21.2% (arm A) versus 50% (arm B). Median progression-free survival and overall survival were, respectively, 19.7 and 33.3 months (arm A) and 30.4 and 39.6 months (arm B). Hematologic and non-hematologic toxic effects during CT/RT were similar in the two arms. CONCLUSION: Induction TPF followed by CT/RT was associated with higher radiologic CR in patients with locally advanced SCCHN with no negative impact on CT/RT feasibility.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/terapia , Neoplasias de Cabeça e Pescoço/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/patologia , Cisplatino/administração & dosagem , Terapia Combinada , Docetaxel , Estudos de Viabilidade , Feminino , Fluoruracila/administração & dosagem , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Dosagem Radioterapêutica , Indução de Remissão , Taxa de Sobrevida , Taxoides/administração & dosagem , Resultado do Tratamento
10.
Int J Oncol ; 32(1): 185-91, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18097558

RESUMO

Urokinase-type plasminogen activator (uPA) and its specific membrane receptor (uPAR) control extracellular matrix proteolysis, cell migration, invasion and cell growth in several cancers. The uPAR released from human cancers is detected in blood as soluble uPAR (suPAR). No information is available on the mechanism(s) of action of suPAR on prostate cancer (PCa) cell growth and invasion. In order to clarify this issue, we tested the effect of a treatment with the human recombinant suPAR (comprising amino acids l-303) on the proliferation, migration and invasion of DU145 cells, a PCa cell line expressing a potent autocrine uPA-uPAR signalling system. The results indicate that suPAR significantly inhibits cell growth, promotes apoptosis and decreases both migration and Matrigel invasion of DU145 cells. The mechanism of action of suPAR seems to be linked to a decrease of ERK and FAK activation. Cleavage of suPAR by chymotripsin reverses these effects. When added to the uPA-negative LNCaP cells, suPAR was ineffective; on the contrary, when LNCaP cells were cultured on fibronectin-coated plates in order to stimulate uPA expression, suPAR significantly decreased cell proliferation. In conclusion, our data suggest that suPAR can function as a potent molecule scavenger for uPA in human PCa cells characterized by high levels of uPA/uPAR as in DU145 cells, while it is ineffective in uPA-deficient LNCaP cells. The molecular mechanism(s) through which suPAR participates in the control of PCa progression may bear relevance for the long-term goal to identify new therapeutic targets aimed at silencing tumours in vivo.


Assuntos
Neoplasias da Próstata/patologia , Receptores de Superfície Celular/fisiologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Masculino , Invasividade Neoplásica , Fosforilação , Neoplasias da Próstata/terapia , Receptores de Ativador de Plasminogênio Tipo Uroquinase
11.
Braz J Med Biol Res ; 39(9): 1233-40, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16981049

RESUMO

Glucocorticoids (Gc) influence the differentiation of neural crest-derived cells such as those composing sympathoadrenal tumors like pheochromocytomas, as well as neuroblastomas and gangliomas. In order to obtain further information on the effects of Gc on cells evolving from the neural crest, we have used the human neuroblastoma cell line SK-N-SH to analyze: 1) the presence and the binding characteristics of Gc receptors in these cells, 2) the effect of dexamethasone (Dex) on the migration of SK-N-SH cells, and 3) the effect of Dex on the organization of the cytoskeleton of SK-N-SH cells. We show that: 1) receptors that bind [(3)H]-Dex with high affinity and high capacity (Kd of 9.6 nM, Bmax of 47 fmol/mg cytosolic protein, corresponding to 28,303 sites/cell) are present in cytosolic preparations of SK-N-SH cells, and 2) treatment with Dex (in the range of 10 nM to 1 microM) has an inhibitory effect (from 100% to 74 and 43%, respectively) on the chemotaxis of SK-N-SH cells elicited by fetal bovine serum. This inhibition is completely reversed by the Gc receptor antagonist RU486 (1 microM), and 3) as demonstrated by fluorescent phalloidin-actin detection, the effect of Dex (100 nM) on SK-N-SH cell migration is accompanied by modifications of the cytoskeleton organization that appear with stress fibers. These modifications did not take place in the presence of 1 microM RU486. The present data demonstrate for the first time that Dex affects the migration of neuroblastoma cells as well as their cytoskeleton organization by interacting with specific receptors. These findings provide new insights on the mechanism(s) of action of Gc on cells originating in the neural crest.


Assuntos
Movimento Celular/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Dexametasona/farmacologia , Glucocorticoides/farmacologia , Neuroblastoma/patologia , Linhagem Celular Tumoral/efeitos dos fármacos , Forma Celular , Quimiotaxia , Humanos , Neuroblastoma/química , Receptores de Glucocorticoides/análise
12.
Braz. j. med. biol. res ; 39(9): 1233-1240, Sept. 2006. ilus, graf
Artigo em Inglês | LILACS | ID: lil-435420

RESUMO

Glucocorticoids (Gc) influence the differentiation of neural crest-derived cells such as those composing sympathoadrenal tumors like pheochromocytomas, as well as neuroblastomas and gangliomas. In order to obtain further information on the effects of Gc on cells evolving from the neural crest, we have used the human neuroblastoma cell line SK-N-SH to analyze: 1) the presence and the binding characteristics of Gc receptors in these cells, 2) the effect of dexamethasone (Dex) on the migration of SK-N-SH cells, and 3) the effect of Dex on the organization of the cytoskeleton of SK-N-SH cells. We show that: 1) receptors that bind [³H]-Dex with high affinity and high capacity (Kd of 9.6 nM, Bmax of 47 fmol/mg cytosolic protein, corresponding to 28,303 sites/cell) are present in cytosolic preparations of SK-N-SH cells, and 2) treatment with Dex (in the range of 10 nM to 1 æM) has an inhibitory effect (from 100 percent to 74 and 43 percent, respectively) on the chemotaxis of SK-N-SH cells elicited by fetal bovine serum. This inhibition is completely reversed by the Gc receptor antagonist RU486 (1 æM), and 3) as demonstrated by fluorescent phalloidin-actin detection, the effect of Dex (100 nM) on SK-N-SH cell migration is accompanied by modifications of the cytoskeleton organization that appear with stress fibers. These modifications did not take place in the presence of 1 æM RU486. The present data demonstrate for the first time that Dex affects the migration of neuroblastoma cells as well as their cytoskeleton organization by interacting with specific receptors. These findings provide new insights on the mechanism(s) of action of Gc on cells originating in the neural crest.


Assuntos
Humanos , Movimento Celular/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Dexametasona/farmacologia , Glucocorticoides/farmacologia , Neuroblastoma/patologia , Forma Celular , Quimiotaxia , Linhagem Celular Tumoral/efeitos dos fármacos , Neuroblastoma/química , Receptores de Glucocorticoides/análise
13.
Oncol Rep ; 15(2): 393-400, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16391860

RESUMO

Prostate cancer (PCa) growth initially depends on circulating androgens. Gonadotropin-releasing hormone (GnRH) agonists are currently used for the treatment of PCa. However, after an initial responsiveness to hormonal deprivation, PCa progresses and metastasizes. Recently, also GnRH antagonists have been used for clinical trials in patients with PCa and the results seem promising. The components of the plasminogen activator (PA) system (urokinase-type PA, uPA; PA inhibitors, PAI-1/2; uPA receptor, uPAR) have been implicated in the local degradation of the extracellular matrix (ECM) and PCa progression. The aim of this study was to test the possible effects of the treatment with an agonist (Leuprolide, GnRH-A) and an antagonist (Cetrorelix, GnRH-ANT) of GnRH on the expression and activity of uPA and PAI-1 in the conditioned media of DU145 and PC3, two PCa androgen-independent cell lines. The involvement of the PA system in the control of cellular migration was also investigated. The results obtained in DU145 and PC3 cells show that both GnRH-A and GnRH-ANT: i) inhibit cell proliferation; ii) significantly decrease the enzymatic activity and the secretion of uPA; iii) significantly increase the protein levels of PAI-1; iv) induce a significant decrease of the migratory and invasion PCa capabilities. This study suggests that GnRH analogues exhibit not only an antiproliferative effect, but also an anti-metastatic action exerted through the inhibition of the activity of PA system and might provide a rational basis for the development of clinical strategies for those tumours that progress towards an androgen-independent condition characterized by a higher metastatic potential.


Assuntos
Antineoplásicos Hormonais/farmacologia , Antagonistas de Hormônios/farmacologia , Invasividade Neoplásica/fisiopatologia , Ativadores de Plasminogênio/efeitos dos fármacos , Neoplasias da Próstata/metabolismo , Western Blotting , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Hormônio Liberador de Gonadotropina/análogos & derivados , Hormônio Liberador de Gonadotropina/antagonistas & inibidores , Hormônio Liberador de Gonadotropina/farmacologia , Humanos , Leuprolida/farmacologia , Masculino
14.
Int J Oncol ; 19(2): 395-9, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11445858

RESUMO

We have recently demonstrated that overexpression of PKCepsilon is oncogenic in colonic epithelial cells. To test whether PI3K might be an upstream effector of PKCepsilon in cell transformation, we have overexpressed the p110alpha PI3K subunit in non-transformed D/WT colonic epithelial cells. Transfectants displayed the major in vitro features of transformed cells. Interestingly, no transformation occurred when p110alpha was co-transfected with a dead-kinase PKCepsilon mutant. The p85alpha subunit of PI3K, displaying a dominant-negative-like effect, was then transfected in PKCepsilon-transformed D/epsilon cells. The transformed profile of these cells was markedly reduced. To identify which by-products of PI3K might be involved in cell transformation we have transfected the D/WT cell line with cDNAs encoding the PI3 kinases hVps34 and C2beta. Overexpression of hVps34 did not cause cell transformation. Conversely, in vitro transformation was observed when C2beta was transfected into D/WT cells. These results indicate that phosphatidylinositol-3 monophosphate does not seem to be involved in cell transformation, and that phosphatidylinositol-3,4 bisphosphate and phosphatidylinositol-3,4,5 trisphosphate are more likely involved in this process. Thus, our data support the hypothesis of a linkage between PI3K and PKCepsilon, and indicate that PI3K may act as a source of second messengers responsible for oncogenic activation of PKCepsilon.


Assuntos
Transformação Celular Neoplásica , Colo/metabolismo , Células Epiteliais/metabolismo , Isoenzimas/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteína Quinase C/metabolismo , Animais , Domínio Catalítico , Divisão Celular/genética , Linhagem Celular , Linhagem Celular Transformada , Transformação Celular Neoplásica/genética , Colo/citologia , Colo/patologia , Ensaio de Unidades Formadoras de Colônias , Células Epiteliais/citologia , Células Epiteliais/patologia , Vetores Genéticos/genética , Isoenzimas/genética , Neoplasias/genética , Neoplasias/patologia , Fenótipo , Fosfatidilinositol 3-Quinases/genética , Proteína Quinase C/genética , Proteína Quinase C-épsilon , Subunidades Proteicas , Ratos , Transdução de Sinais , Transfecção
15.
J Mol Endocrinol ; 26(3): 185-91, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11357055

RESUMO

We investigated the presence of glucocorticoid receptors (GR) as well as the role of glucocorticoids (Gc) in the control of proliferation of the androgen-independent prostate cancer cell line, DU145. We detected the presence of a specific high affinity binding site (K(d) 2.3 nM) for [(3)H]dexamethasone ([(3)H]Dex) in the cytosolic preparations of DU145 cells; the density of these binding sites is significantly higher than that detected in HA22T/VGH and in HepG2, two hepatoma cell lines classically considered models for the study of GR. Immunocytochemistry studies confirmed the presence of GR in the cytosolic compartment of DU145 cells; GR undergo translocation to the nucleus following exposure to dexamethasone (Dex). The functional activity of GR present in DU145 cells was also studied by analyzing the potency of Dex in inducing chloramphenicol acyltransferase (CAT) activity in DU145 cells transfected with a glucocorticoid/progesterone response element (GRE/PRE) tkCAT plasmid (GRE/PREtkCAT plasmid). The results have shown that Dex stimulates the transcriptional activity of GR in transfected DU145 cells with an EC(50) of 9.65 nM and a maximal induction of sevenfold above basal levels. Finally, a dose-dependent (IC(50) 3.14 nM) decrease of DU145 cell numbers was observed after their exposure to Dex for 4 days; this effect was counteracted by the presence of the steroid antagonist, RU486. In conclusion, the present data suggest a possible role of corticoids in the control of the growth of androgen-independent prostate cancer.


Assuntos
Androgênios/fisiologia , Neoplasias da Próstata/metabolismo , Receptores de Glucocorticoides/metabolismo , Divisão Celular/efeitos dos fármacos , Cloranfenicol O-Acetiltransferase/genética , Dexametasona/farmacologia , Humanos , Imuno-Histoquímica , Masculino , Neoplasias da Próstata/patologia , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/fisiologia , Transcrição Gênica/fisiologia , Células Tumorais Cultivadas
16.
Oncol Rep ; 7(2): 347-51, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10671684

RESUMO

Recent experimental evidence suggests that melatonin, the major pineal hormone, might possess oncostatic properties. The present experiments were performed to verify whether melatonin might modulate the growth of androgen-dependent prostate cancer cells (LNCaP) and to obtain information on its possible mechanism of action. We have shown that melatonin, when given in the nanomolar range, significantly inhibits the proliferation of LNCaP cells; moreover, the pineal gland hormone affects cell cycle distribution by inducing an accumulation of the cells in G0/G1 and a decrease in S phase. To investigate the mechanism of action of melatonin, by RT-PCR analysis we were able to demonstrate the expression, in prostate cancer cells, of a mRNA coding for the membrane Mel1a melatonin receptor. However, by radioreceptor assay, no detectable binding of 2-[125I]iodomelatonin could be observed in membrane preparations from these cells, suggesting that the levels of translation of the mRNA for Mel1a are possibly too low to mediate the antiproliferative action of the hormone. This hypothesis is further supported by the following observations: i) melatonin analogs, specifically acting through membrane receptors (i.e., 2-bromomelatonin), were completely ineffective in modulating prostate cancer cell proliferation; ii) melatonin failed to prevent forskolin-induced cAMP accumulation. These results indicate that melatonin, at nanomolar concentrations, exerts a direct antiproliferative action on androgen-dependent prostate cancer cells, significantly affecting their distribution throughout the cell cycle. Membrane receptors do not seem to be involved in the oncostatic action of the pineal gland hormone.


Assuntos
Antioxidantes/farmacologia , Melatonina/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Androgênios/metabolismo , Antioxidantes/uso terapêutico , Divisão Celular/efeitos dos fármacos , Humanos , Masculino , Melatonina/uso terapêutico , Neoplasias Hormônio-Dependentes/tratamento farmacológico , Neoplasias Hormônio-Dependentes/patologia , Neoplasias da Próstata/metabolismo , Receptores de Superfície Celular/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores de Melatonina , Células Tumorais Cultivadas
17.
Endocrinology ; 140(11): 5250-6, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10537155

RESUMO

Evidence has accumulated indicating that LHRH might behave as an autocrine/paracrine growth inhibitory factor in some peripheral tumors. However, LHRH receptors in tumor cells have not been fully characterized, so far. The present experiments were performed to analyze: 1) the messenger RNA expression; 2) the molecular size; and 3) the signal transduction pathway of LHRH receptors in prostate cancer. For these studies, the human androgen-dependent LNCaP and androgen-independent DU 145 prostate cancer cell lines were used. 1) By RT-PCR, a complementary DNA product, which hybridized with a 32P-labeled oligonucleotide probe specific for the pituitary LHRH receptor complementary DNA, was found both in LNCaP and in DU 145 cells. 2) Western blot analysis, using a monoclonal antibody raised against the human pituitary LHRH receptor, revealed the presence of a protein band of approximately 64 kDa (corresponding to the molecular mass of the pituitary receptor) in both cell lines. 3) In LNCaP and DU 145 cells, pertussis toxin completely abrogated the antiproliferative action of a LHRH agonist (LHRH-A). Moreover, LHRH-A substantially antagonized the pertussis toxin-catalyzed ADP-ribosylation of a Galpha(i) protein. Finally, LHRH-A significantly counteracted the forskolin-induced increase of intracellular cAMP levels in both cell lines. These data demonstrate that the LHRH receptor, which is present in prostate cancer cells, independently of whether they are androgen-dependent or not, corresponds to the pituitary receptor, in terms of messenger RNA expression and protein molecular size. However, at variance with the receptor of the gonadotrophs, prostate cancer LHRH receptor seems to be coupled to the Galpha(i) protein-cAMP signal transduction pathway, rather than to the Galpha(q/11)-phospholipase C signaling system. This might be responsible for the different actions of LHRH in anterior pituitary and in prostate cancer.


Assuntos
Expressão Gênica , Neoplasias da Próstata/metabolismo , RNA Mensageiro/análise , Receptores LHRH/genética , Receptores LHRH/metabolismo , Transdução de Sinais , Adenosina Difosfato Ribose/metabolismo , Animais , Western Blotting , AMP Cíclico/metabolismo , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Gosserrelina/farmacologia , Humanos , Masculino , Peso Molecular , Toxina Pertussis , Hipófise/química , Ratos , Ratos Sprague-Dawley , Receptores LHRH/química , Células Tumorais Cultivadas , Fosfolipases Tipo C/metabolismo , Fatores de Virulência de Bordetella/farmacologia
18.
Endocrinology ; 140(1): 329-34, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9886842

RESUMO

We have previously shown that LHRH agonists exert a direct and specific inhibitory action on the proliferation of the androgen-independent DU 145 prostate cancer cell line; however, the cellular mechanisms mediating this antiproliferative action are not well defined. It is well known that the insulin-like growth factor (IGF) system plays a crucial role in the local regulation of the growth of androgen-independent prostate cancer. The present experiments were performed to evaluate whether LHRH agonists might exert their antimitogenic effect by interfering with the activity of the locally expressed IGF system. To this purpose, the effects of the LHRH agonist Zoladex (LHRH-A) on 1) the mitogenic action of IGF-I, 2) the tyrosine phosphorylation of type 1 IGF-I receptor (IGF-IR), 3) the concentration of IGF-IR, and 4) the secretion of IGF-binding protein-3 were studied. The results obtained show that in DU 145 cells, LHRH-A 1) counteracts the mitogenic action of IGF-I in a dose-dependent manner, 2) prevents the IGF-I-induced tyrosine phosphorylation of the IGF-IR, 3) reduces the concentration of IGF-IR without affecting its Kd value, and 4) does not affect the secretion of IGF-binding protein-3 in the conditioned medium from these cells. These data suggest that LHRH agonists may inhibit the proliferation of human androgen-independent prostate tumor cells by interfering with some of the cellular mechanisms mediating the stimulatory action of the IGF system.


Assuntos
Hormônio Liberador de Gonadotropina/agonistas , Neoplasias da Próstata/patologia , Somatomedinas/fisiologia , Western Blotting , Divisão Celular/efeitos dos fármacos , Gosserrelina/farmacologia , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Fator de Crescimento Insulin-Like I/farmacologia , Fator de Crescimento Insulin-Like II/farmacologia , Masculino , Neoplasias da Próstata/metabolismo , Células Tumorais Cultivadas , Tirosina/metabolismo
19.
Minerva Chir ; 54(11): 809-12, 1999 Nov.
Artigo em Italiano | MEDLINE | ID: mdl-10638155

RESUMO

Sclerosing peritonitis (abdominal cocoon syndrome) is a rare chronic affection of the peritoneum; its etiology is multifactorial and it affects all ages. Capsulating membranes seem to grow from a poorly cellular connective deposition in many layers on the intestinal peritoneum and are casually detected by surgery or autopsy. The placement of the peritoneovenous shunt can favour the deposition of fibrin on the visceral peritoneum, determining the formation of sclerosing membranes. When mechanical occlusion occurs, surgery is the choice therapy in order to remove the obstacle and, if possible, the membranes as well.


Assuntos
Derivação Peritoneovenosa/efeitos adversos , Peritônio/patologia , Peritonite/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose , Síndrome
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