RESUMO
Transformation and uptake of [8-14C]-adenosine and its synthetic analog 2',3'-O-isopropylideneadenosine was studied in Zajdel hepatoma cells and their homogenates. Uptake and deamination of adenosine and 2',3'-O-isopropylideneadenosine by Zajdel hepatoma cells proceed differently. A small part of adenosine is phosphorylated and then it is included into biosynthesis of polymer substances. The uptake and deamination of 2',3'-O-isopropylideneadenosine by hepatoma cells occurs more intensively than uptake and deamination of adenosine. The formed 2',3'-O-isopropylideneadenosine is not splitted by purine nucleoside phosphorylase and is accumulated in cells in the incubation medium that lead to cell death. The same rate of 2',3'-O-isopropylideneadenosine deamination in cells and their homogenates indicates its high penetrability through plasma membranes. The high uptake of 2',3'-O-isopropylideneadenosine contrary to adenosine leads to deaggregation of cells and their destruction.
Assuntos
Adenosina/análogos & derivados , Adenosina/metabolismo , Neoplasias Hepáticas Experimentais/metabolismo , Animais , Células Cultivadas , Purinas/metabolismo , Ratos , Células Tumorais Cultivadas/metabolismoRESUMO
The carbohydrate determinants of the cell surface of neuroblastoma C 1300 clone N 18 have been investigated by light microscopy with a panel of 11 lectins as cytochemical reagents. The expression of N- and O-glycanes with a predominance of 3-4 antigenic N-glycosyl chains was revealed. The characteristic feature of neuroblastoma cells is an abundance of an antigen A surface determinant. A strong correlation is shown between the intensity of lectin binding and index of cell agglutination. After the binding of lectins with living cells the lectin-receptor complexes are clustered, endocytosed and for 4 hours are concentrated as microvesicles in the cytoplasm compact area. Heterogeneity of the neuroblastoma cell population on the binding of peanut and Lens culinaris lectins is revealed.