Vikhanskaya F, Clerico L, Valenti M, Stanzione MS, Broggini M, Parodi S, Russo P. Mechanism of resistance to cisplatin in a human ovarian-carcinoma cell line selected for resistance to doxorubicin: possible role of p53.
Int J Cancer 1997;
72:155-9. [PMID:
9212237 DOI:
10.1002/(sici)1097-0215(19970703)72:1<155::aid-ijc22>3.0.co;2-h]
[Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A possible novel mechanism of cross-resistance to cisplatin (CDDP) in the doxorubicin-resistant ovarian-cancer cell line A2780-DX3, which displays atypical multidrug resistance, is presented. A2780-DX3 is found to be more resistant than the parental line A2780 in terms of CDDP-induced cytotoxicity and apoptosis. Resistance is not related to the amount of cross-links. Topoisomerase-II (topII) protein levels were similar in both cell lines, with lower cleavage activity in A2780-DX3 cells. The parental and the doxorubicin-resistant cells expressed the same level of c-erb2, which could be implicated in CDDP resistance. bcl2 was almost undetectable in both cell lines. At the same time, we found strong induction of p53, waf-1 and bax protein levels after CDDP treatment in the A2780, but not in the A2780-DX3, cell line. Treatment of both cell lines with mitomycin C (MMC), which acts with a mechanism different from CDDP, caused equal accumulation of p53 and induction of bax. We found that A2780-DX3 cells exhibit altered cellular localization of p53 protein in comparison with A2780. A significant proportion of p53 in A2780-DX3 cells was found in the cytoplasmic compartment, and CDDP treatment induced a functional p53 protein in the nucleus of A2780 much more strongly than in A2780-DX3, which coincides with an increase of transcriptional activity of p53 in treated A2780 cells. We propose that the cross-resistance to CDDP in the A2780-DX3 cell line may be due to inactivation of a CDDP-dependent p53-accumulation pathway.
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