Table 1.

Development of cells resistant to CDDP and PTX

Cells	IC50 CDDP (μM)	IC50 PTX (nM)	CDP (CDDP + PTX)
IGROV-1	5.40 ± 0.57	60.9 ± 1.22	0.24 ± 0.04
IGROV-1 PTES	12.1 ± 1.01b	554 ± 15.5b	0.52 ± 0.04b
SKOV-3	15.6 ± 1.20	78.0 ± 6.40	0.16 ± 0.20
SKOV-3 PTES	64.1 ± 4.10a	1230 ± 300c	1.20 ± 0.20c

CDP = Combination Dose Proportion. CDP is considered a combination of doses and exposure times that when equal to 1 are clinically achievable (CDP = 1 means 20 μM CDDP for 1 h plus 100 nM PTX for 3 h). For instance, a CDP of 0.5 means that the inhibition of growth by 50% was achieved using half the concentration of each of the drugs (i.e., 10 μM CDDP for 1 h plus 50 nM PTX for 3 h). ^ap < 0.001; ^bp < 0.01; ^cp < 0.05 (Student’s t-test) compared to parental cells.