Table 1 Synergistic interaction between imatinib (Ima) and metformin (Metf) in HCT15 cells as revealed by combination index (CI) values.

Ima (μM)	1.25	2.5	5	10	Type of interaction
CI at 0.25 mM Metf	0.52	0.56	0.58	0.71	Synergistic
CI at 0.5 mM Metf	0.51	0.52	0.52	0.66	Synergistic
CI at 1 mM Metf	0.51	0.6	0.63	0.86	Synergistic

CI values were calculated by using the CompuSyn software according to the recommendations of Chou-Talaly.