Gene expression changes with induction of in-vitro platinum-resistance in ovarian cancer cell lines.. Homo sapiens

We treated 8 human ovarian cancer cell lines with cisplatin in treatment/recovery cycles to induce in-vitro resistance to the drug. Microarrays measured gene expression at baseline and after each dose schedule (after recovery). Overall design: OVCA cells lines (T8, OVCAR5, OV2008, IGROV1, C13, A2780S, A2780CP, and A2008) were used in the study. Cells were subject to sequential treatment with increasing doses of cis-diammine-dichloroplatinum (cisplatin, CIS), using three dosing schedules resulting in a total of 144 treatment/expansion cycles. Treatment schedules A, B and C included three treatments with 1, 2 and 3μg/ml CIS respectively, followed by three treatments with 3, 4 and 5μg/ml, respectively. Each CIS-treatment was followed by a cell recovery/expansion phase. Both CIS-resistance and genome-wide expression changes were measured serially in each cell line at baseline and after 3 and 6 CIS-treatment/expansion cycles. CIS-resistance was quantified using CellTiter-96, MTS proliferation assays (Fisher Scientific) and genome-wide expression was performed using Affymetrix Human U133 Plus 2.0 GeneChips as previously described.