RESUMO
An altered apoptotic response represents a pivotal feature of cancer and is involved in cancerogenesis and resistance to chemotherapy. So far, however, only a few studies have been devoted to survey caspase content in malignant cell lines and primary tumor specimens. In this report, we investigated the expression of two pivotal caspases, 3 and 8, in 63 neuroblastoma specimens by three complementary techniques (i.e., reverse transcriptase polymerase chain reaction, immunoblotting, and immunohistochemistry). We confirmed the frequent absence of caspase 8 expression. Moreover and most important, we demonstrated, for the first time to our knowledge, that a significant percentage of neuroblastomas lack caspase 3 mRNA and protein. Both caspase alterations do not show any correlation with tumor stage and MYCN status. Immunohistochemistry showed a large number of caspase-negative cell islets also present in positive samples. Our findings suggest that the absence of caspases might play an important role in neuroblastoma development and resistance to apoptosis-based treatments.
Assuntos
Caspases/deficiência , Neuroblastoma/enzimologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Caspase 3 , Caspase 8 , Caspase 9 , Caspases/genética , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Immunoblotting , Imuno-Histoquímica , Proteína Proto-Oncogênica N-Myc , Neuroblastoma/tratamento farmacológico , Neuroblastoma/genética , Neuroblastoma/patologia , Proteínas Nucleares/genética , Proteínas Oncogênicas/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
BACKGROUND: Congenital nephrotic syndrome of the Finnish type (CNF) is an autosomal recessive disorder mainly caused by mutations in the nephrin gene (NPHS1). The frequency of this gene is highest in Finland but the condition occurs in all populations, with and without Finnish ancestry. The NPHS1 gene is located in the chromosomal region 19q13.1 and consists of 29 exons. METHODS: Polymerase chain reaction (PCR), restriction and sequence analyses were used to screen 15 CNF Italian patients for mutations in this gene. RESULTS: No Italian patients had the typical Finnish mutations, a 2bp deletion in exon 2 (Fin-major) and a nonsense mutation in exon 26 (Fin-minor). We found 13 mutations including deletions, insertions, nonsense and missense mutations. Seven of these have never been described before. We also found one nucleotide change in the promoter region and one common polymorphism. NPHS1 missense mutations were confirmed by analysis of a healthy control population. CONCLUSIONS: Our study provides further evidence that loss of function of the nephrin gene is the main cause of congenital nephrotic syndrome of the Finnish type in Italian patients.
