Table 1.

Resistance of ovarian cancer cells to cisplatin after metformin treatment

Cells	Cisplatin IC50 (μg/mL)	Fractional inhibitory index
A2780	3.12 ± 0.048
CP70
0 mM/metformin	29.16 ± 0.805	9.34
0.01 mM/ metformin	26.43 ± 0.437	8.45
0.1 mM/metformin	23.52 ± 0.432	7.53
1 mM/metformin	19.26 ± 0.215*	6.17
10 mM/ metformin	10.04 ± 0.327*	3.23

*P < 0.05 compared with 0.01 mM metformin