Fig. 3.

pHLIP uptake and retention is pH dependent. (A) Tumor growth curves of EV and CAIX-overexpressing HCT116 cells in nude mice. CAIX overexpression enhanced tumor growth. (B) The uptake and retention of pHLIP Var3 in CAIX-overexpressing tumors (normalized to volume) was significantly higher than in EV controls over time. (C) AZA treatment reduced pHLIP retention significantly within 24 h. Mice bearing 4T1 tumors were injected with pHLIP and treated with AZA or left untreated. The mice were imaged at 1 h and 24 h postinjection, and the decline in fluorescence was calculated. The increase in pH as effected by AZA accelerated the decrease in pHLIP fluorescence significantly (n = 4–6 per group; data are mean ± SEM).