The effect of taxol (TX) and cisplatin (CDDP), singly or in association, was assessed on two human ovarian cancer cell lines, one sensitive (A2780) and one resistant (A2780 cp8) to CDDP. Cell lines showed a similar sensitivity to TX, whereas different cytotoxicity results were obtained in the two cell lines as a function of TX and CDDP sequence. Specifically TX followed by CDDP induced simply additive effects in both cell lines, whereas the opposite sequence produced antagonistic effects in A2780 cells and synergistic effects in A2780 cp8 cells. TX, with or without CDDP, induced oligonucleosomal DNA fragmentation typical of the apoptotic process, but the biochemical mechanisms undergoing apoptosis were different in the two cell lines. In fact, in A2780 cells, TX (with or without CDDP) treatment markedly increased p53 as well as p21(waft) protein expression. In A2780 cp8 cells, drug treatment enhanced p53 levels, whereas the expression of p21(waft) was always undetectable at mRNA and protein levels. In the latter cell line, a premature activation of p34(cdc2) kinase was observed in correspondence with the drug-induced increase in the S-phase cell fraction. Such an activation was not ascribable to an increase in the overall expression of p34(cdc2) or cyclin B1 proteins, but to a dephosphorylation of p34(cdc2) kinase. Overall, our results indicate that TX-induced apoptosis in human ovarian cancer cells may be sustained by different events at the cell cycle-control level.
|Number of pages||8|
|Journal||British Journal of Cancer|
|Publication status||Published - 1998|
- Cell cycle-related proteins
- Ovarian cancer
ASJC Scopus subject areas
- Cancer Research