Early evaluation for treatment efficacy of 5-fluorouracil and hyperthermia on HCT-116 colon cancer cells by fluorine-18-fluorodeoxyglucose uptake.

BACKGROUND: Fluorine-18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography imaging can be used to assess the treatment efficacy of chemotherapy and prognosis. The aim of this study was to determine the uptake rate of (18)F-FDG in colon cancer HCT-116 cells, and to evaluate the treatment efficacy of chemotherapy, hyperthermia and thermo-chemotherapy through the uptake inhibition rate of (18)F-FDG. METHODS: The uptake rate of (18)F-FDG in HCT-116 cells was determined at various experimental conditions. The inhibition rate of cell growth, uptake rate of (18)F-FDG and uptake inhibition rate of (18)F-FDG in HCT-116 cells treated with 5-fluorouracil (5-FU) at various concentrations were determined. In HCT-116 cells subjected to chemotherapy (5-FU, 100 µg/ml), hyperthermia (43°C, 40 minutes) and thermo-chemotherapy for 24 hours, the inhibition rate of cell growth and uptake inhibition rate of (18)F-FDG were determined; early apoptosis, the morphology and ultrastructure of HCT-116 cells were examined; and the contents of glucose and lactate dehydrogenase (LDH) in the cell culture medium of HCT-116 cells were determined. One-way analysis of variance (ANOVA) and correlation analyses were conducted by using SPSS 16.0 software. RESULTS: The uptake rate of (18)F-FDG in HCT-116 cells was (44.25 ± 2.19)%. Under the condition of adding 5-FU at various concentrations for 24 hours, the uptake rate of (18)F-FDG was negatively correlated with 5-FU dosage (r = -0.879, P < 0.01); the inhibition rate of cell growth revealed a positive correlation with the uptake inhibition rate of (18)F-FDG (r = 0.831, P < 0.01). In HCT-116 cells subjected to hyperthermia, chemotherapy, and thermo-chemotherapy for 24 hours, the uptake inhibition rates of (18)F-FDG were (12.94 ± 2.80)%, (28.25 ± 4.59)%, and (21.60 ± 3.68)%, respectively. The early apoptotic rates of HCT-116 cells were (9.80 ± 0.16)%, (19.80 ± 2.40)%, and (15.70 ± 1.80)%, respectively. Moreover, the contents of glucose and LDH in cell culture medium of HCT-116 cells after treatments were higher than those before treatment. CONCLUSION: The uptake inhibition rate of (18)F-FDG can be used for early evaluation of hyperthermia and 5-FU treatment efficacy on cancer cells although hyperthermia (43°C, 40 minutes) does not reveal the synergistic effect on 5-FU at the low dosage.