Human malignant mesothelial cells: Variability of ultrastructural features in established and nude mice transplanted cell lines

Abstract

The aim of this study was to determine, by transmission electron microscopy, the differentiation features of 21 human malignant mesothelioma cell lines (HMCLs) established from 13 specimens of 12 confirmed human malignant mesotheliomas, and of tumours induced in nude mice injected with 16 HMCLs. Fifty per cent of HMCLs showed typical mesothelial differentiation (long and slender microvilli, desmosomes, perinuclear intermediate filaments); 29 per cent did not show differentiation; and the remainder were poorly differentiated. Three human tumour specimens gave several different HMCLs; the cell lines obtained from a given tumour exhibited variable mesothelial differentiation. Eleven HMCLs were compared with the native tumour. Four were similar to the tumour and seven were less well differentiated, in most cases in relation to their microvilli. With six HMCLs, tumours induced in nude mice were less well differentiated than the corresponding cell lines, whereas with four HMCLs, tumours were equally or better differentiated. However, in most nude mice tumours, typical mesothelial microvilli were present. These results show that cell lines established from malignant mesothelioma may exhibit dedifferentiated features. However, while the variability in ultrastructural differentiation may result from the culture microenvironment, it could also be related to the state of differentiation, of the native tumour sample and to tumour cell heterogeneity.

Heterogeneity of mesothelioma cell lines as defined by altered genomic structure and expression of theNF2 gene

“…Cell cultures were grown from pleural effusions (9 cases), pleural tissue samples (8 cases) and ascitic fluid (1 case). The culture methods have been described elsewhere (Zeng et al, 1994;Fleury-Feith et al, 1995). Due to the lack of specific marker for mesothelial cells, cell line characterization was made on the basis of co-expression of cytokeratin and vimentin associated with the absence of CEA and Leu-M1.…”

Cell cycle checkpoint status in human malignant mesothelioma cell lines: response to gamma radiation

“…We believe that this is the first report of such a point mutation in a characterised human mesothelioma cell line. This cell line was obtained from a confirmed human mesothelioma case and exhibited both the ultrastructural features and immunocytochemical characteristics of mesothelial cells based on coexpression of cytokeratin and vimentin, and absence of carcinoembryonic antigen expression (Zeng et al, 1994;Fleury-Feith et al, 1995). More recent markers, calretinin and CAK1 were also expressed in this cell line.…”

Computer-assisted differential diagnosis of malignant mesothelioma based on syntactic structure analysis

“…These results encourage the use of SSA in automated expert systems, where quality assurance demands very low false-negative rates. Those expert systems may use SSA to automatically scan a section to select fields of interest and subsequently analyze these fields at higher magnifications at which nuclear cytometrical and morphometric features can be measured (30,31). This combination will permit an extended description of the tissue and will most probably increase overall performance.…”