RESUMO
Literature on the role of multidisciplinary team (MDT) in cancer is still controversial. We aimed to investigate MDT impact on a panel of indicators in breast cancer care in a single-center retrospective study performed in a Cancer Reference Center in Italy. We analysed the diagnostic and therapeutic care pathway (DTCP) of 266 early breast cancer patients managed by our MDT during 2019-2020. Process indicators reflecting the change of the diagnostic and therapeutic care pathways occurred after the MDT discussion were computed. Further, the performance of some quality care indicators in breast cancer care since the establishment of the MDT activity and the breast cancer MDT members' perceptions were also investigated. According to our study, the MDT approach improves breast cancer management by increasing the completion of staging and by encouraging neo-adjuvant treatment and an appropriate and faster surgery. In MDT members' perspective it also improves decision-making and training and creates a positive work environment. Globally, our study encourages MDT rollout in breast cancer care. However, to enhance the reliability and comparability of the results of studies investigating MDT effectiveness in clinical practice, shared guidelines on its operationalisation are strongly desirable.
Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/terapia , Procedimentos Clínicos , Estudos Retrospectivos , Reprodutibilidade dos Testes , Percepção , Equipe de Assistência ao PacienteRESUMO
The Notch signaling pathway plays a critical role in embryonic development, self-renewal of stem cells, and carcinogenesis. Aberrant Notch signaling has been linked to a wide variety of cancers, and can either suppress or promote tumors depending on the cell type and the context. Increasingly it is being realized that Notch signaling not only involves in the pathogenesis and development of esophageal adenocarcinoma (EAC), it also promotes the growth of EAC cells and also involved in the maintenance of EAC cancer stem cells. The efficacy of gamma-secretase inhibitor (GSI) in EAC treatment could have a major impact on easing the burden of this devastating disease. Therefore, it appears that inhibition of Notch sensitizes EAC cells to chemotherapeutic agents, which should lead to a better and more durable response to neoadjuvant chemotherapy (NAC). In this review, we bring to highlight how Notch plays a role in the development, tumorigenicity, and stemness of EAC cells, and how Notch signaling pathway could be a promising therapeutic target for the treatment of human EAC.
Assuntos
Adenocarcinoma/metabolismo , Neoplasias Esofágicas/metabolismo , Receptores Notch/metabolismo , Transdução de Sinais , Adenocarcinoma/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Animais , Esôfago de Barrett/metabolismo , Neoplasias Esofágicas/tratamento farmacológico , Humanos , Transdução de Sinais/efeitos dos fármacosRESUMO
Whole brain reirradiation for the treatment of multiple brain metastases has shown promising results. However, concerns remain over the possible neurotoxic effects of the cumulative dose as well as the questionable radiosensitivity of recurrent metastases. A second reirradiation of the whole brain is ordinarily performed in our department for palliative purposes in patients presenting with multiple metastatic brain progression. For this study, an investigational third whole brain reirradiation has been administered to highly selected patients to obtain disease control and delay progression. Clinical outcomes and neurological toxicity were also evaluated.
Assuntos
Neoplasias Encefálicas , Radiocirurgia , Reirradiação , Humanos , Neoplasias Encefálicas/secundário , Irradiação Craniana/efeitos adversos , Irradiação Craniana/métodos , Estudos Retrospectivos , Encéfalo , Radiocirurgia/métodosRESUMO
PURPOSE: The aims of this study were to describe bilateral penetrating keratoplasty (PK) in a newborn and to analyze the data of PKs performed in Italy during the 5-year period 1999-2003 in children under 4 years of age. METHODS: A male newborn had PK at age 3 months and 5 months for near-blindness secondary to severe congenital corneal clouding in both eyes. The infant''s explanted corneas were subjected to histochemical and ultrastructural analyses. Data regarding the number of PKs performed in Italy on 0-4-year-olds were obtained from the Web site of the Italian Ministry of Health. RESULTS: The postoperative courses were uncomplicated, and 42 months of follow-up data show bilateral graft transparency and substantial improvement in visual acuity despite high-grade myopia and nystagmus. At the ultrastructural level, the main alterations involved the endothelial cells and Descemet membrane. A total of 45 PKs were performed in Italy on patients 0-4 years old from 1999 through 2003; only nine involved babies under 1 year of age. CONCLUSIONS: In babies with congenital corneal opacities, early PK can reduce severe amblyopia. However, the risk of intra- and postoperative complications in PK is high. Based on the 42-month follow-up, the anatomic and functional results achieved in the current patient are satisfactory despite the presence of nystagmus and postoperative high-grade myopia. This study shows that PKs are rarely performed, in Italy, in children aged 0-4 years, and very few are done during the first year of life.
Assuntos
Opacidade da Córnea/cirurgia , Ceratoplastia Penetrante/tendências , Adolescente , Ambliopia/prevenção & controle , Pré-Escolar , Opacidade da Córnea/congênito , Humanos , Lactente , Complicações Intraoperatórias , Itália , Masculino , Complicações Pós-Operatórias , Doadores de TecidosRESUMO
We introduce a simple approach for the efficient generation of tunable narrow-bandwidth picosecond pulses synchronized to broadband femtosecond ones. Second harmonic generation in the presence of large group velocity mismatch between the interacting pulses transfers a large fraction of the energy of a broadband fundamental frequency pulse into a narrowband second harmonic one. Using a periodically poled stoichiometric lithium tantalate crystal coupled to an infrared optical parametric amplifier, we generated 200-nJ pulses with spectral width lower than 8.5 cm(-1) and tunability from 720 to 890 nm. Energy scaling and extension of the tuning range are straightforward.
RESUMO
Notch proteins are plasma membrane-spanning receptors that mediate important cell fate decisions such as differentiation, proliferation, and apoptosis. The mechanism of Notch signaling remains poorly understood. However, it is clear that the Notch signaling pathway mediates its effects through intercellular contact between neighboring cells. The prevailing model for Notch signaling suggests that ligand, presented on a neighboring cell, triggers proteolytic processing of Notch. Following proteolysis, it is thought that the intracellular portion of Notch (N(ic)) translocates to the nucleus, where it is involved in regulating gene expression. There is considerable debate concerning where in the cell Notch functions and what proteins serve as effectors of the Notch signal. Several Notch genes have clearly been shown to be proto-oncogenes in mammalian cells. Activation of Notch proto-oncogenes has been associated with tumorigenesis in several human and other mammalian cancers. Transforming alleles of Notch direct the expression of truncated proteins that primarily consist of N(ic) and are not tethered to the plasma membrane. However, the mechanism by which Notch oncoproteins (generically termed here as N(ic)) induce neoplastic transformation is not known. Previously we demonstrated that N1(ic) and N2(ic) could transform E1A immortalized baby rat kidney cells (RKE) in vitro. We now report direct evidence that N1(ic) must accumulate in the nucleus to induce transformation of RKE cells. In addition, we define the minimal domain of N1(ic) required to induce transformation and present evidence that transformation of RKE cells by N1(ic) is likely to be through a CBF1-independent pathway.
Assuntos
Transformação Celular Neoplásica , Proteínas de Membrana/genética , Proteínas Nucleares , Receptores de Superfície Celular , Fatores de Transcrição , Animais , Sítios de Ligação , Divisão Celular , Linhagem Celular , Linhagem Celular Transformada , Núcleo Celular/metabolismo , Meios de Cultura , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Expressão Gênica , Células HeLa , Humanos , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina , Proteínas de Membrana/metabolismo , Mutagênese , Ratos , Receptor Notch1RESUMO
Notch genes encode a family of transmembrane proteins that are involved in many cellular processes such as differentiation, proliferation, and apoptosis. Although it is well established that all four Notch genes can act as oncogenes, the mechanism by which Notch proteins transform cells remains unknown. Previously, we have shown that transformation of RKE cells can be conditionally induced by hormone activation of Notch(ic)-estrogen receptor (ER) chimeras. Using this inducible system, we show that Notch(ic) activates transcription of the cyclin D1 gene with rapid kinetics. Transcriptional activation of cyclin D1 is independent from serum-derived growth factors and de novo synthesis of secondary transcriptional activators. Moreover, hormone activation of Notch(ic)-ER proteins induces CDK2 activity in the absence of serum. Upregulation of cyclin D1 and activation of CDK2 by Notch(ic) result in the promotion of S-phase entry. These data demonstrate the first evidence that Notch(ic) proteins can directly regulate factors involved in cell cycle control and affect cellular proliferation. Furthermore, nontransforming Notch(ic) proteins do not induce cyclin D1 expression, indicating that the mechanism of transformation involves cell cycle deregulation through constitutive expression of cyclin D1. Finally, we have identified a CSL [stands for CBF1, Su(H), and Lag-1] binding site within the human and rat cyclin D1 promoters, suggesting that Notch(ic) proteins activate cyclin D1 transcription through a CSL-dependent pathway.
Assuntos
Quinases relacionadas a CDC2 e CDC28 , Ciclina D1/genética , Quinases Ciclina-Dependentes/metabolismo , Proteínas de Drosophila , Proteínas de Membrana/metabolismo , Proteínas Nucleares , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Superfície Celular/metabolismo , Tamoxifeno/análogos & derivados , Ativação Transcricional , Ciclo Celular , Linhagem Celular Transformada , Quimiocina CCL4 , Quimiocinas CC , Ciclina D1/metabolismo , Quinase 2 Dependente de Ciclina , Proteínas de Ligação a DNA/metabolismo , Ativação Enzimática , Humanos , Proteína de Ligação a Sequências Sinal de Recombinação J de Imunoglobina , Proteínas Inflamatórias de Macrófagos , Proteínas de Membrana/genética , Regiões Promotoras Genéticas , Proteínas/metabolismo , RNA Mensageiro , Receptores de Superfície Celular/genética , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Receptores Notch , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Repressoras/metabolismo , Tamoxifeno/metabolismoRESUMO
The Rel family of proteins includes a number of proteins involved in transcriptional control, such as the retroviral oncoprotein v-Rel, c-Rel, the Drosophila melanogaster developmental protein Dorsal, and subunits of the transcription factor NF-kappa B. These proteins are related through a highly conserved domain of approximately 300 amino acids, called the Rel homology domain, that contains dimerization, DNA binding, and nuclear targeting functions. Also within the Rel homology domain, there is a conserved consensus sequence (Arg-Arg-Pro-Ser) for phosphorylation by cyclic AMP-dependent protein kinase (PKA). We used linker insertion mutagenesis and site-directed mutagenesis to determine the importance of this sequence for the transformation of avian spleen cells by v-Rel and the subcellular localization of c-Rel in chicken embryo fibroblasts (CEF). The insertion of 2 amino acids (Pro-Trp) within this sequence completely abolished transformation and transcriptional repression by v-Rel and resulted in a shift in the localization of c-Rel from cytoplasmic to nuclear in CEF. When the conserved Ser within the PKA recognition sequence was replaced by Ala, there was no significant effect on transformation and transcriptional repression by v-Rel or on cytoplasmic retention of c-Rel. However, when this Ser was changed to Asp or Glu, transformation and transcriptional repression by v-Rel were significantly inhibited and c-Rel showed a diffuse nuclear and cytoplasmic localization in CEF. Although a peptide containing the recognition sequence from v-Rel can be phosphorylated by PKA in vitro, this site is not constitutively phosphorylated to a high degree in vivo in transformed spleen cells incubated with okadaic acid. Our results indicate that the transforming and transcriptional repressing activities of v-Rel and the cytoplasmic retention of c-Rel are dependent on the structure of the conserved PKA recognition motif. In addition, they suggest that phosphorylation at the conserved PKA site could have a negative effect on transformation and transcriptional repression by v-Rel and induce the nuclear localization of c-Rel.
Assuntos
Transformação Celular Neoplásica , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Oncogênicas de Retroviridae/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Western Blotting , Galinhas , Citoplasma/metabolismo , DNA , Dados de Sequência Molecular , Mutação , Proteínas Oncogênicas v-rel , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-rel , Especificidade por Substrato , Transcrição Gênica , TripsinaRESUMO
The Notch genes of Drosophila melanogaster and vertebrates encode transmembrane receptors that help determine cell fate during development. Although ligands for Notch proteins have been identified, the signaling cascade downstream of the receptors remains poorly understood. In human acute lymphoblastic T-cell leukemia, a chromosomal translocation damages the NOTCH1 gene. The damage apparently gives rise to a constitutively activated version of NOTCH protein. Here we show that a truncated version of NOTCH1 protein resembling that found in the leukemic cells can transform rat kidney cells in vitro. The transformation required cooperation with the E1A oncogene of adenovirus. The transforming version of NOTCH protein was located in the nucleus. In contrast, neither wild-type NOTCH protein nor a form of the truncated protein permanently anchored to the plasma membrane produced transformation in vitro. We conclude that constitutive activation of NOTCH similar to that found in human leukemia can contribute to neoplastic transformation. Transformation may require that the NOTCH protein be translocated to the nucleus. These results sustain a current view of how Notch transduces a signal from the surface of the cell to the nucleus.
Assuntos
Transformação Celular Neoplásica/genética , Leucemia Experimental/genética , Leucemia-Linfoma de Células T do Adulto/genética , Proteínas de Membrana/genética , Receptores de Superfície Celular/genética , Fatores de Transcrição , Proteínas E1A de Adenovirus/genética , Alelos , Animais , Transporte Biológico , Compartimento Celular , Núcleo Celular/metabolismo , Humanos , Ratos , Receptor Notch1 , Receptor Notch2 , Deleção de SequênciaRESUMO
Primary empty sella (PES) is characterized by the herniation of the subarachnoid space within the sella, which is often associated with variable degrees of flattening of the pituitary gland in patients without previous pituitary pathologies. PES pathogenetic mechanisms are not well known but seem to be due to a sellar diaphragm incompetence, associated to the occurrence of upper sellar or pituitary factors, as intracranial hypertension and change of pituitary volume. As PES represents in a majority of cases, a neuroradiological findings without any clinical implication, the occurrence of endocrine, neurological and opthalmological symptoms, due to the above describes anatomical alteration, which delineates from the so called PES syndrome. Headache, irregular menses, overweight/obesity and visual disturbances compose the typical picture of PES syndrome and can be the manifestation of an intracranial hypertension, often associated with PES. Although hyperprolactinemia and growth hormone deficit represent the most common endocrine abnormalities, PES syndrome is characterized by heterogeneity both in clinical manifestation and hormonal alterations and can sometime reach severe extremes, as occurrence of papilledema, cerebrospinal fluid rhinorrhea and worsening of visual acuity. Consequently, a multidisciplinary approach, with the integration of endocrine, neurologic and ophthalmologic expertise, is strongly advocated and recommended for a properly diagnosis, management, treatment and follow-up of PES syndrome and all of the related abnormalities.
Assuntos
Doenças Assintomáticas , Síndrome da Sela Vazia/diagnóstico , Encefalocele/diagnóstico , Hipófise/diagnóstico por imagem , Sela Túrcica/diagnóstico por imagem , Espaço Subaracnóideo/diagnóstico por imagem , Síndrome da Sela Vazia/diagnóstico por imagem , Síndrome da Sela Vazia/fisiopatologia , Síndrome da Sela Vazia/terapia , Encefalocele/diagnóstico por imagem , Encefalocele/fisiopatologia , Encefalocele/terapia , Hormônio do Crescimento Humano/deficiência , Hormônio do Crescimento Humano/metabolismo , Humanos , Hiperprolactinemia/etiologia , Hiperprolactinemia/prevenção & controle , Hipertensão Intracraniana/etiologia , Hipertensão Intracraniana/prevenção & controle , Imageamento por Ressonância Magnética , Neuroimagem , Papiledema/etiologia , Papiledema/prevenção & controle , Hipófise/metabolismo , Hipófise/fisiopatologia , Sela Túrcica/fisiopatologia , Índice de Gravidade de Doença , Espaço Subaracnóideo/fisiopatologiaRESUMO
The SMOOTHENED inhibitor vismodegib is FDA approved for advanced basal cell carcinoma (BCC), and shows promise in clinical trials for SONIC HEDGEHOG (SHH)-subgroup medulloblastoma (MB) patients. Clinical experience with BCC patients shows that continuous exposure to vismodegib is necessary to prevent tumor recurrence, suggesting the existence of a vismodegib-resistant reservoir of tumor-propagating cells. We isolated such tumor-propagating cells from a mouse model of SHH-subgroup MB and grew them as sphere cultures. These cultures were enriched for the MB progenitor marker SOX2 and formed tumors in vivo. Moreover, while their ability to self-renew was resistant to SHH inhibitors, as has been previously suggested, this self-renewal was instead WNT-dependent. We show here that loss of Trp53 activates canonical WNT signaling in these SOX2-enriched cultures. Importantly, a small molecule WNT inhibitor was able to reduce the propagation and growth of SHH-subgroup MB in vivo, in an on-target manner, leading to increased survival. Our results imply that the tumor-propagating cells driving the growth of bulk SHH-dependent MB are themselves WNT dependent. Further, our data suggest combination therapy with WNT and SHH inhibitors as a therapeutic strategy in patients with SHH-subgroup MB, in order to decrease the tumor recurrence commonly observed in patients treated with vismodegib.
Assuntos
Neoplasias Cerebelares/metabolismo , Proteínas Hedgehog/metabolismo , Meduloblastoma/metabolismo , Proteínas Wnt/antagonistas & inibidores , Via de Sinalização Wnt , Anilidas/farmacologia , Animais , Linhagem Celular Tumoral , Neoplasias Cerebelares/tratamento farmacológico , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Modelos Animais de Doenças , Células HEK293 , Humanos , Masculino , Meduloblastoma/tratamento farmacológico , Meduloblastoma/genética , Meduloblastoma/patologia , Camundongos , Camundongos Transgênicos , Piridinas/farmacologia , Distribuição Aleatória , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Canais de Cátion TRPC/deficiência , Canais de Cátion TRPC/genética , Canais de Cátion TRPC/metabolismo , Transfecção , Proteína Supressora de Tumor p53/deficiência , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Alcaloides de Veratrum/farmacologia , Proteínas Wnt/metabolismoRESUMO
To understand the regulation of expression of the chicken c-rel gene, we cloned genomic sequences upstream of the start site of transcription of c-rel. Sequence analysis shows that the c-rel promoter is a GC-rich promoter that lacks a TATA box. In addition, there are putative binding sites for several transcription factors, including an NF-kappa B consensus binding site. Primer extension showed that there is one major start site (site 1) for transcription in chicken embryo fibroblasts and two major start sites in a v-rel-transformed chicken spleen cell line. In transient assays using c-rel promoter sequences and the CAT reporter gene, we found that vRel repressed expression from the c-rel promoter. Other viral oncoproteins and a non-transforming v-rel deletion mutant did not repress the c-rel promoter. Repression occurred through sequences located within 125 bp of the start of transcription. However, mutation of the consensus NF-kappa B binding site did not affect the level of transcription from the c-rel promoter, nor did it interfere with repression by vRel, even though vRel could bind to the wild-type, but not the mutant, version of this sequence in vitro. These results suggest that the vRel protein can repress transcription through an indirect mechanism.
Assuntos
NF-kappa B/metabolismo , Regiões Promotoras Genéticas , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Proto-Oncogenes , Animais , Sequência de Bases , Sítios de Ligação , Células Cultivadas , Embrião de Galinha , Galinhas , Deleção Cromossômica , Clonagem Molecular , Éxons , Íntrons , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Oligodesoxirribonucleotídeos , Plasmídeos , Proteínas Proto-Oncogênicas c-rel , Transcrição GênicaRESUMO
Notch genes encode a family of evolutionarily conserved transmembrane receptors that are involved in many distinct cellular processes such as differentiation, proliferation and apoptosis. Notch function has been shown to be required both during development and in adult life. Moreover, several studies on spontaneous human tumors and in experimental models demonstrate that three of the four mammalian Notch genes can act as oncogenes. The mechanism by which Notch proteins induce neoplastic transformation is not known. In order to determine the early signaling events mediated by Notch during cellular transformation we constructed several inducible alleles of Notch(ic) by fusing portions of Nic to the hormone-binding domain of the estrogen receptor. Here we show that Notch(ic)-ER chimeras are conditionally activated by 4-Hydroxytamoxifen (OHT) in a dose-dependent manner. Clonal RKE cell lines expressing Notch(ic)-ER chimeras display hormone-dependent transformation in vitro. Transformation mediated by Notch(ic)-ER is reversible and chronic stimulation is necessary for the maintenance of the transformed phenotype. In response to hormone activation Notch(ic)-ER chimeras become hyperphosphorylated and accumulate in the nucleus of the cell; indicating that both phosphorylation and nuclear localization are required for Notch transforming activity.
Assuntos
Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas/metabolismo , Hormônios/metabolismo , Proteínas de Membrana/metabolismo , Receptores de Estradiol/metabolismo , Proteínas de Saccharomyces cerevisiae , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Linhagem Celular , Transformação Celular Neoplásica , Proteínas de Ligação a DNA/genética , Relação Dose-Resposta a Droga , Antagonistas de Estrogênios/farmacologia , Proteínas Fúngicas/genética , Hormônios/farmacologia , Humanos , Rim/citologia , Rim/patologia , Proteínas de Membrana/genética , Fosforilação , Ratos , Receptores de Estradiol/genética , Receptores Notch , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Tamoxifeno/análogos & derivados , Tamoxifeno/farmacologiaRESUMO
The v-Rel oncoprotein of the avian Rev-T retrovirus is a member of a family of related transcription factors, which also includes the subunits of NF-kappa B and several other interacting cellular proteins. We show here that v-Rel specifically increased expression from a reporter plasmid containing multiple Sp1 binding sites approximately sixfold in chicken embryo fibroblasts (CEFs), even though v-Rel did not bind directly to these sites. v-Rel also increased expression from a reporter plasmid containing a human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in which the kappa B binding sites were mutated but which still contained intact Sp1 binding sites. The increase in Sp1-site transactivation does not precisely correlate with transformation by v-Rel since one non-transforming v-Rel mutant still induced expression from the Sp1 site-containing promoter. v-Rel appears to increase expression from Sp1 site-containing promoters by affecting the transactivation domain of Sp1, since v-Rel increased the activity of a Gal4-Sp1 fusion protein, which contains the Sp1 transactivation domain but lacks the Sp1 DNA-binding domain. As compared with v-Rel, c-Rel induced only a slight increase in expression from the reporter plasmid containing Sp1 sites. However, v-Ras and v-Src (but not v-Myb) induced increases in transcription from the reporter plasmid containing Sp1 sites to the same extent as v-Rel, but through pathways that appear to be independent from v-Rel. These results suggest that certain oncoproteins might increase transcription from many genes that contain Sp1 binding sites, and that this might be important for certain aspects of transformation by these proteins.
Assuntos
Regulação da Expressão Gênica , Oncogenes , Regiões Promotoras Genéticas , Proteínas Oncogênicas de Retroviridae/fisiologia , Fator de Transcrição Sp1/metabolismo , Ativação Transcricional , Animais , Sequência de Bases , Embrião de Galinha , Proteínas de Ligação a DNA/metabolismo , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos/química , Proteína Oncogênica pp60(v-src)/farmacologia , Proteínas Oncogênicas v-myb , Proteínas Oncogênicas v-rel , Proteínas Proto-Oncogênicas/farmacologia , Proteínas Proto-Oncogênicas c-rel , Proteínas Proto-Oncogênicas p21(ras)/farmacologia , Proteínas Oncogênicas de Retroviridae/farmacologia , Transcrição GênicaRESUMO
We isolated and sequenced a 3727 bp clone of the c-rel proto-oncogene from a chicken embryo fibroblast (CEF) cDNA library. Sequence comparison to the retroviral oncogene v-rel showed conclusively that the v-rel protein is truncated at both the amino- and carboxy-termini as compared to the c-rel protein. In vitro transcription and translation of this clone yielded a 68,000 dalton polypeptide that co-migrated on SDS polyacrylamide gels with p68c-rel from avian spleen cells. We inserted this c-rel cDNA clone into an avian retroviral vector (pJD214c-rel), and over-expressed p68c-rel in CEF. Over-expression of p68c-rel did not induce morphological transformation of these cells. Unlike p59v-rel, which is a nuclear protein in CEF, indirect immunofluorescence showed that p68c-rel in JD214c-rel infected CEF is located exclusively in the cytoplasm of these cells, even though the sequence of p68c-rel showed that it contains a nuclear localizing sequence identical to the one previously identified in p59v-rel. Furthermore, the c-rel protein does contain a nuclear localizing sequence which can function in CEF since replacement of the v-rel nuclear localizing sequence with the homologous domain from c-rel resulted in a hybrid rel protein that was located in the nucleus in CEF. Mutant c-rel proteins, deleted of the carboxy-terminal sequences not present in p59v-rel, localized to the nucleus in CEF. Our results show that the carboxy-terminus of p68c-rel inhibits nuclear localization of the protein, and suggest that subcellular location may be a form of regulation of the activity of p68c-rel.
Assuntos
Clonagem Molecular , Expressão Gênica , Proteínas Proto-Oncogênicas/genética , Proto-Oncogenes , Sequência de Aminoácidos , Animais , Sequência de Bases , Transformação Celular Neoplásica , Células Cultivadas , Embrião de Galinha , Citoplasma/enzimologia , Fibroblastos/enzimologia , Dados de Sequência Molecular , Peso Molecular , Proteínas Nucleares/genética , Biossíntese de Proteínas , Proteínas Tirosina Quinases/genética , Proteínas Proto-Oncogênicas/isolamento & purificação , Proteínas Proto-Oncogênicas c-rel , Homologia de Sequência do Ácido Nucleico , Transcrição GênicaRESUMO
We have isolated a chicken cDNA that encodes the retinoblastoma susceptibility gene product (RB). The predicted amino acid sequence of the chicken RB protein is highly similar to that of the mouse, human and Xenopus RB proteins in regions of known functions; however, chicken RB has distinct species-specific differences, including a shorter N-terminal region as compared to the mouse and human RB proteins. In vitro-translated chicken RB co-migrates on SDS-polyacrylamide gels with endogenous RB synthesized in transformed chicken spleen cells. Finally, chicken RB is located in the nucleus of chicken embryo fibroblasts when overexpressed from a retroviral vector.
Assuntos
Proteína do Retinoblastoma/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Embrião de Galinha , Galinhas , DNA , DNA Complementar , Humanos , Dados de Sequência Molecular , Homologia de Sequência de AminoácidosRESUMO
The purpose of this study was to find out whether the combination of inactive doses of paracetamol (PARA) and morphine was able to change dynorphin (DYN) A levels, evaluated by radioimmunoassay, and whether naloxone or [(-)-2-(3 furylmethyl)-normetazocine] (MR 2266), a kappa-opioid antagonist, modifies or prevents the activity of this combination on nociception and on DYN levels. The work was suggested by our previous findings which demonstrated that inactive doses of PARA and morphine, when given in combination, share an antinociceptive effect, and that PARA, at antinociceptive doses, decreases DYN levels in the frontal cortex, thus indicating a selective action within the CNS. Our present results demonstrate that the combination of inactive doses of PARA (100 mg/kg) and morphine (3 mg/kg) is just as effective in decreasing the levels of DYN A as full antinociceptive doses of PARA or morphine alone in the frontal cortex of the rat. The values, expressed in pmol/g tissue, were: control = 2.83 +/- 0.20; paracetamol (100) = 2.60 +/- 0.23; morphine (3) = 2.73 +/- 0.24; paracetamol + morphine = 1.34 + 0.16 (P < 0.05). The decrease was partially antagonised by MR 2266, but not by naloxone, suggesting that the activity of PARA and morphine in combination on DYN A levels could be mediated, at least in part, through kappa-receptors, although other systems may be involved. On the other hand, both naloxone and MR 2266 prevented the antinociceptive effect of the combination in the hot plate test. All our experimental data suggest that PARA and morphine in combination exert their antinociceptive effect through the opioidergic system, which in turn may cause a decrease in DYN levels in the CNS of the rat.
Assuntos
Acetaminofen/farmacologia , Analgésicos/farmacologia , Encéfalo/efeitos dos fármacos , Dinorfinas/metabolismo , Morfina/farmacologia , Acetaminofen/uso terapêutico , Analgésicos/uso terapêutico , Analgésicos não Narcóticos/farmacologia , Analgésicos não Narcóticos/uso terapêutico , Analgésicos Opioides/farmacologia , Analgésicos Opioides/uso terapêutico , Animais , Encéfalo/metabolismo , Combinação de Medicamentos , Masculino , Morfina/uso terapêutico , Dor/tratamento farmacológico , Medição da Dor , Ratos , Ratos WistarRESUMO
The opioid peptide dynorphin is thought to be implicated in specific types of seizures. In particular, complex partial seizures have been shown to cause release of dynorphin, activation of prodynorphin gene expression, and new peptide synthesis in the hippocampus. In this study, the kinetics of the seizure-induced changes in prodynorphin mRNA and ir-dynorphin A levels in the hippocampus have been compared with those induced in the temporal and frontal cortex, i.e., in other regions involved in the pathophysiology of complex partial seizures. Experiments have been run using kindling, one of the most valuable models of partial epilepsy. In the hippocampus (1) prodynorphin mRNA levels transiently increase (threefold) 1 h after kindled seizures, and return to baseline by 2 h, and (2) dynorphin A levels are slightly decreased at 1 h, but increase (twofold) at 2 h and return to baseline by 6 h. In the temporal and in the frontal cortex, a late (beginning at 2 h) and prolonged (up to 24 h) decrease in both prodynorphin mRNA and ir-dynorphin A levels have been observed. These data suggest that differential changes in dynorphin metabolism occur in different brain areas after seizures. The mechanisms and functional implications of this observation remain to be investigated.
Assuntos
Dinorfinas/metabolismo , Encefalinas/metabolismo , Excitação Neurológica/fisiologia , Precursores de Proteínas/metabolismo , RNA Mensageiro/metabolismo , Convulsões/metabolismo , Convulsões/fisiopatologia , Animais , Modelos Animais de Doenças , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Male Wistar rats were administered with naloxone (1 mg/kg i.p.) or MR 2266 (5 mg/kg i.p) 15 min before paracetamol (400 mg/kg i.p.) treatment and the pain threshold was evaluated. Rats were subjected to the hot-plate and formalin tests and immunoreactive dynorphin A (ir-dynorphin A) levels were measured in the hypothalamus, hippocampus, striatum, brainstem, frontal and parietal-temporal cortex by radioimmunoassay. Pretreatment with naloxone abolished paracetamol antinociceptive activity both in hot-plate and in the first phase, but not in the second phase of the formalin test, while MR 2266 pretreatment was able to antagonise paracetamol effect either in the hot-plate test or in both phases of the formalin test. Among different brain areas investigated paracetamol significantly decreased ir-dynorphin A levels only in the frontal cortex. MR 2266 but not naloxone reversed the decrease in ir-dynorphin A levels elicited by paracetamol. Paracetamol seems to exert its antinociceptive effect also through the opioidergic system modulating dynorphin release in the central nervous system (CNS) of the rat, as suggested by the decrease in the peptide levels.
Assuntos
Acetaminofen/farmacologia , Analgésicos não Narcóticos/farmacologia , Química Encefálica/efeitos dos fármacos , Dinorfinas/análise , Nociceptores/efeitos dos fármacos , Animais , Benzomorfanos/farmacologia , Lobo Frontal/química , Lobo Frontal/efeitos dos fármacos , Masculino , Naloxona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Medição da Dor/efeitos dos fármacos , Limiar da Dor/efeitos dos fármacos , Ratos , Ratos WistarRESUMO
Chronic administration of morphine or cocaine affects opioid gene expression. To better understand the possible existence of common neuronal pathways shared by different classes of drugs of abuse, we studied the effects of methamphetamine on the gene expression of the opioid precursor prodynorphin and on the levels of peptide dynorphin A in the rat brain. Acute (6 mg/kg, intraperitoneally, i.p.) and chronic (6 mg/kg, i.p. for 15 days) methamphetamine markedly raised prodynorphin mRNA levels in the hypothalamus, whereas no effect was observed in the hippocampus. Dynorphin A levels increased after chronic treatment in the hypothalamus and in the striatum, whereas no significant changes were detected after acute treatment. These results indicate that methamphetamine affects prodynorphin gene expression in the hypothalamus, which may be an important site (also for its relevant neuroendocrine correlates) for opioidergic mechanisms activated by addictive drugs.