Drug-related chromosomal changes in chemoresistant human ovarian carcinoma cells.

Four resistant sublines were derived from the sensitive human ovarian carcinoma IGROV 1 (OV1-P) cell line by exposure to increasing concentrations of vincristine, doxorubicin, and cisplatinum. The vincristine-resistant sublines expressed the MDR phenotype associated with a complete reversion of malignant properties. Cytogenetic studies of sensitive and resistant cells have been repeatedly performed over a 1-year period. Consistent and stable drug-related chromosomal structural rearrangements have been observed in each resistant population affecting chromosomes 3, 4, 6, 8, 11, 22, and X. The most significant result was the presence in OV1/P cells of a minor subclone with a del(11)(p13) marker that represented the whole OV1/VCR population. This result suggests a possible role of this deletion either in the drug-selection process, or in the malignant reversion.