Occurrence and morphology of tumors induced in nude mice transplanted with chrysotile-transformed rat pleural mesothelial cells

Nitrosulindac (NCX 1102): a new nitric oxide-donating non-steroidal anti-inflammatory drug (NO-NSAID), inhibits proliferation and induces apoptosis in human prostatic epithelial cell lines

BACKGROUND

The aim of our study was to explore the anti-tumoral potential of the Nitric Oxide-Donating Non-Steroidal Anti-Inflammatory Drugs (NO-NSAID) NCX1102 (nitrosulindac), on three human prostatic epithelial cell lines at varying degree of transformation (PNT1A, LNCaP, and PC3).

METHODS

Cytotoxicity, anti-proliferative effects, cell-cycle alterations, morphological changes, and apoptosis were investigated after treatment with nitrosulindac in comparison to the native molecule sulindac. Involvement of the polyamine pathway in the action of nitrosulindac was also examined.

RESULTS

Nitrosulindac but not sulindac exerted a cytotoxic effect on all cell lines and an anti-proliferative effect on LNCaP and PC3 cells only. Nitrosulindac differentially altered the cell cycle, induced mitotic arrest and displayed a pro-apoptotic activity in all cell lines. Finally, the polyamine pathway does not seem to be involved in the mechanism of nitrosulindac action.

CONCLUSIONS

Our results demonstrate the anti-proliferative and proapoptotic activity of nitrosulindac on prostate cancer cell lines and suggest its potential interest for new strategies in the management of prostate cancer.

Pleuro-pulmonary tumours detected by clinical and chest X-ray analyses in rats transplanted with mesothelioma cells

New strategies for cancer therapy must be developed, especially in severe neoplasms such as malignant pleural mesothelioma. Animal models of cancer, as close as possible to the human situation, are needed to investigate novel therapeutical approaches. Orthotopic transplantation of cancer cells is then relevant and efforts should be made to follow up tumour evolution in animals. In the present study, we developed a method for the orthotopic growth of mesothelioma cells in the pleural cavity of Fischer 344 and nude rats, along with a procedure for clinical survey. Two mesothelioma cell lines, of rat and human origin, were inoculated by transthoracic puncture. Body weight determination and chest X-ray analyses permitted the follow-up of tumour evolution by identifying different stages. Autopsies showed that tumours localized on the whole pleural cavity (diaphragm, parietal pleura), mediastinum and pericardium. Tumour morphology and antigenic characteristics were consistent with those of the inoculated cells and were similar in both types of rats inoculated with the same cell type. These results demonstrate that mesothelioma formation in rats can be followed up by clinical and radiographic survey after gentle intrathoracic inoculation of mesothelioma cells, thus allowing the definition of stages of interest for further experimental trials.

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

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.