A The expression of LRPPRC in SW480 and HCT116 cells treated with GAA at a range of concentrations for 24 h. B The combined therapeutic effect of GAA and 5FU in SW480 cells. C The interaction coefficient of GAA and 5FU: coefficient of drug interaction (CDI) > 1 indicates antagonism, CDI = 1 indicates addition, and CDI < 1 indicates synergism. D SW480 cells were treated with 5FU (20 μg/ml) and/or GAA (20 μM) for 48 h. Apoptosis was detected by flow cytometry (left). Statistical analysis of apoptosis (right). E SW480 cells were treated for 36 h with 5FU and/or GAA. The protein expression of Bax, Bcl2, total-PARP and cleaved-PARP was detected by WB. F Schematic diagram of combined treatment with GAA and 5FU in vivo. G The volume of subcutaneously transplanted tumours in 4 groups: mock, 5FU, GAA, and GAA + 5FU. H The weight of subcutaneously transplanted tumours in the 4 groups. I IHC of cleaved-PARP, Ki-67, LRPPRC and MDR1 in subcutaneous transplanted tumours from four groups. Scale bars, 100 μm.