RESUMEN
Mutations in the Adenomatous Polyposis Coli (APC) tumor suppressor gene or the beta-catenin gene are present in most colon cancers and less frequently in other tumor types. In this study, we screened 24 human breast cancer cell lines and three immortalized human breast epithelial cell lines for alterations in beta- and gamma-catenin and APC by western blotting, protein truncation assay and DNA sequence analysis. In one cell line (DU 4475), an APC mutation was identified (E1577stop) that resulted in expression of truncated APC. This mutation was associated with elevated cytosolic beta-catenin levels, probably due to loss of APC function, as in colon cancers. No mutations were found in exon 3 of the beta- or gamma-catenin genes. We conclude that APC mutations and beta-catenin upregulation may occur with low frequency in human breast cancer cells.
Asunto(s)
Neoplasias de la Mama/genética , Proteínas del Citoesqueleto/genética , Genes APC/genética , Transactivadores , Proteína de la Poliposis Adenomatosa del Colon , Western Blotting , Mama/citología , Neoplasias de la Mama/metabolismo , Línea Celular Transformada , Proteínas del Citoesqueleto/metabolismo , Análisis Mutacional de ADN , Desmoplaquinas , Humanos , Mutación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Tumorales Cultivadas , beta Catenina , gamma CateninaRESUMEN
The buccalin-related peptides, buccalin A and buccalin B, are members of a family of cotransmitters that modulate neuromuscular transmission in Aplysia. In this study, a third buccalin-related peptide, buccalin C, was purified from neuronal elements in the accessory radula closer, a muscle involved in the animal's feeding behavior. Oligonucleotide probes based upon the amino acid sequence of buccalin C were used to isolate cDNA clones that encode a buccalin precursor polypeptide. The buccalin precursor contains 19 distinct buccalin-related peptides, several of which are present in multiple copies. The buccalin gene appears to be present in a single copy, with one allele containing a small insert. Expression of this gene occurs in a tissue-specific manner and mRNA transcripts are abundant within neurons in the Aplysia CNS. This large family of neuropeptides may exert extraordinarily complex modulatory actions at synapses where they serve as cotransmitters.
Asunto(s)
Aplysia/genética , ADN/aislamiento & purificación , Neuropéptidos/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , ADN/química , Expresión Génica , Hibridación in Situ , Datos de Secuencia Molecular , Sistema Nervioso/química , Neuropéptidos/química , Sondas de Oligonucleótidos , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción , Precursores de Proteínas/química , Señales de Clasificación de Proteína/química , Análisis de SecuenciaRESUMEN
The honeybee hive product, propolis, is a folk medicine employed for treating various ailments. Many important pharmaceutical properties have been ascribed to propolis, including anti-inflammatory, antiviral, immunostimulatory and carcinostatic activities. Propolis extracts have provided an active component identified as caffeic acid phenethyl ester (CAPE), which was readily prepared in one step. Differential cytotoxicity has been observed in normal rat/human versus transformed rat/human melanoma and breast carcinoma cell lines in the presence of CAPE.