RESUMO
Allelic deletions on human chromosome 12q24 are frequently reported in a variety of malignant neoplasms, indicating the presence of a tumor suppressor gene(s) in this chromosomal region. However, no reasonable candidate has been identified so far. In this study, we report the cloning and functional characterization of a novel mitochondrial protein with tumor suppressor activity, henceforth designated MITOSTATIN. Human MITOSTATIN was found within a 3.2-kb transcript, which encoded a approximately 62 kDa, ubiquitously expressed protein with little homology to any known protein. We found homozygous deletions and mutations of MITOSTATIN gene in approximately 5 and approximately 11% of various cancer-derived cells and solid tumors, respectively. When transiently overexpressed, MITOSTATIN inhibited colony formation, tumor cell growth and was proapoptotic, all features shared by established tumor suppressor genes. We discovered a specific link between MITOSTATIN overexpression and downregulation of Hsp27. Conversely, MITOSTATIN knockdown cells showed an increase in cell growth and cell survival rates. Finally, MITOSTATIN expression was significantly reduced in primary bladder and breast tumors, and its reduction was associated with advanced tumor stages. Our findings support the hypothesis that MITOSTATIN has many hallmarks of a classical tumor suppressor in solid tumors and may play an important role in cancer development and progression.
Assuntos
Neoplasias da Mama/genética , Cromossomos Humanos Par 12/genética , Genes Supressores de Tumor , Proteínas de Neoplasias/biossíntese , Proteínas Supressoras de Tumor/fisiologia , Neoplasias da Bexiga Urinária/genética , Animais , Apoptose/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proteínas de Transporte , Divisão Celular/genética , Linhagem Celular Tumoral/metabolismo , Linhagem Celular Tumoral/ultraestrutura , Transformação Celular Neoplásica/genética , Clonagem Molecular , Progressão da Doença , Regulação para Baixo , Feminino , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP27/biossíntese , Proteínas de Choque Térmico HSP27/genética , Proteínas de Choque Térmico , Humanos , Masculino , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Chaperonas Moleculares , Dados de Sequência Molecular , Proteínas de Neoplasias/genética , RNA Mensageiro/genética , RNA Neoplásico/genética , Proteínas Recombinantes de Fusão/fisiologia , Especificidade da Espécie , Ensaio Tumoral de Célula-Tronco , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/isolamento & purificação , Neoplasias da Bexiga Urinária/metabolismo , Neoplasias da Bexiga Urinária/patologiaRESUMO
LCA as a decision-supporting tool in planning integrated municipal solid waste management is not, as yet, widely used in Italy. This paper presents a study concerning the application of the LCA methodology to support the development of the new waste management plan for the Bologna District. The main goal of the study was to show decision-makers at the political level the benefits obtainable with the use of LCA, in terms of the identification and quantification of the potential environmental impacts of different waste management strategies. The integrated waste management system of the Bologna District includes waste collection and transport, sorting, recycling, composting, incineration and landfilling. Three scenarios, referring to 2006 and assuming the presence of 950,000 inhabitants and the production of approximately 566,000 t of waste in the district, have been compared. A detailed model has been developed in order to capture effects related to the waste fraction from separated collection and to the different waste treatments. The discussion of the results has focussed in particular on the greenhouse effect and the acidification potential. On the basis of the results obtained, the analysis of an additional scenario characterised by a further increase in separated collection has been put forward.
Assuntos
Eliminação de Resíduos/métodos , Poluição do Ar/análise , Dióxido de Carbono/análise , Conservação dos Recursos Naturais , Técnicas de Apoio para a Decisão , Efeito Estufa , Itália , SoloRESUMO
Leucine-rich repeats and immunoglobulin-like domains-1 (LRIG1) is a transmembrane protein with an ectodomain containing 15 leucine-rich repeats (LRRs) homologous to mammalian decorin and the Drosophila kekkon1 gene. In this study, we demonstrate that a soluble ectodomain of LRIG1, containing only the LRRs, inhibits ligand-independent epidermal growth factor receptor (EGFR) activation and causes growth inhibition of A431, HeLa and MDA-468 carcinoma cells. In contrast, cells that do not express detectable levels of EGFR fail to respond to soluble LRIG1. However, when a functional EGFR gene is introduced in these cells, they become growth-inhibited by soluble LRIG1 protein. Furthermore, we demonstrate the existence of high-affinity (K(d)=10 nM) binding sites on the A431 cells that can be competitively displaced (up to 75%) by molar excess of EGF. Even more powerful effects are obtained with a chimeric proteoglycan harboring the N-terminus of decorin, substituted with a single glycosaminoglycan chain, fused to the LRIG1 ectodomain. Both proteins also inhibit ligand-dependent activation of the EGFR and extracellular signal-regulated protein kinase 1/2 signaling in a rapid and dose-dependent manner. These results suggest a novel mechanism of action evoked by a soluble ectodomain of LRIG1 protein that could modulate EGFR signaling and its growth-promoting activity. Attenuation of EGFR activity without physical downregulation of the receptor could represent a novel therapeutic approach toward malignancies in which EGFR plays a primary role in tumor growth and survival.
Assuntos
Receptores ErbB/metabolismo , Regulação da Expressão Gênica/fisiologia , Glicoproteínas de Membrana/genética , Sequência de Aminoácidos , Animais , Sítios de Ligação , Células CHO , Proliferação de Células , Cricetinae , Cricetulus , Decorina , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Genes Dominantes , Células HeLa , Humanos , Ligantes , Dados de Sequência Molecular , Ligação Proteica , Proteoglicanas/genética , Proteoglicanas/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/patologiaRESUMO
A review of worldwide clinical trials with norfloxacin in the treatment of uncomplicated urinary tract infections (UTIs), as well as our personal experience with 215 assessable patients, is presented. Almost all patients received 400 mg b.i.d. for 3-15 days. Bacteriological eradication (10(4) CFU/ml of urine or less) was achieved in more than 90% of patients. Short-term therapy (3 days) with norfloxacin proved to be as effective and tolerable as a 10- to 14-day conventional therapeutic schedule in the treatment of lower uncomplicated UTIs. Overall incidence of drug-related adverse experiences was 2.3%.
