Positron emission tomography imaging of human colon cancer xenografts in mice with [18F]fluorothymidine after TAS-102 treatment

Purpose TAS-102 is an orally administered anticancer agent composed of α,α,α-trifluorothymidine (FTD) and thymidine phosphorylase inhibitor (TPI). This study assessed 3′-deoxy-3′-[ 18 F]fluorothymidine ([ 18 F]FLT) uptake after TAS-102 administration. Methods The human colorectal carcinoma cell lines HCT116, HT29, HCT8 and SW620 were exposed to FTD for 2 h, further incubated for 0, 2 and 24 h, and assayed for [ 3 H]FLT uptake, nucleoside transport, thymidine kinase 1 (TK1) expression and TK1 activity. Static and 2-h dynamic [ 18 F]FLT positron emission tomography (PET) was performed in mice bearing HT29 or SW620 tumours orally administered with vehicle or TAS-102. Results FTD decreased the viability of all cell lines, whereas increased [ 3 H]FLT uptake ( P