Early Metabolic Flare in Squamous Cell Carcinoma after Chemotherapy is a Marker of Treatment Sensitivity In Vitro

PURPOSE: Early metabolic response with a decrease in glucose demand after cytotoxic treatment has been reported to precede tumor volume shrinkage. However, preclinical studies report of a very early rise in metabolism, a flare, following treatment. To elucidate these observations, we performed an experimental study on early metabolic response with sequential analysis of metabolic changes. METHODS: Three squamous cell carcinoma cell lines and one nontumorigenic cell line were exposed to cisplatin. The uptake of the fluorescent glucose analogue 2-NBDG was examined at days 1-6 using fluorescence microscopy. The relation between 2-NBDG-uptake and cell survival was evaluated. RESULTS: The tumor cells exhibited a high uptake of 2-NBDG, whereas the uptake in the nonmalignant cells was low. The more cisplatin sensitive cell lines exhibited a more pronounced metabolic flare than the less sensitive cell line. CONCLUSION: A metabolic flare was a very early sign of treatment response and potentially it could be used as an early marker of treatment sensitivity.