Supplementary Figures S1-S9 from [<sup>18</sup>F]fluorothymidine PET Informs the Synergistic Efficacy of Capecitabine and Trifluridine/Tipiracil in Colon Cancer

Figure S1 shows IC50 of 5-fluorouracil in cell lines. Figure S2 shows mRNA expression of ENT1, TK1, TS, TP, and DPD in human colon cancer cell lines. Table S3 shows relationship between 5-fluorouracil sensitivity (IC50) and mRNA expression of 5-fluorouracil transporter or metabolic enzymes. Figure S4 shows correlation of capecitabine sensitivity in human colon cancer xenografts (%TGI) with 5-fluorouracil sensitivity (IC50) in vitro. Figure S5 shows correlation of capecitabine sensitivity in human colon cancer xenografts (%TGI) with the maximal SUV (SUVmax) of [18F]FLT PET. Figure S6 shows capecitabine induced changes in TK1 activity of ex vivo tumor tissues on day 4 in HCT8, HT29, and HCT116 human colon cancer xenografts. Figure S7 and S8 show immunohistochemical evaluation of ENT1 and TP expression in ex vivo xenografts and correlation with %TGI by capecitabine. Figure S9 shows correlation of capecitabine sensitivity in human colon cancer xenografts (%TGI) with ex vivo mRNA expression of 5-fluorouracil transporter and metabolic enzymes.