Establishment of an acquired tamoxifen-resistant human breast cancer cell line and its mechanism of 18F-FDG uptake reduction / 中华核医学与分子影像杂志

ABSTRACT

Objective To establish the acquired tamoxifen (TAM)-resistant human breast cancer cell line T47D-TamR,compare the 18F-FDG uptake rate between T47D-TamR and its parental cell line T47D,and study the mechanism.Methods Long-term step-wise drug stimulation was used for cell line T47D-TamR establishment and then the cell proliferation and resistance index (RI) were determined by MTT assay.The 18F-FDG uptake rates of T47D-TamR and T47D cells were measured in the setting of different cell counts,reaction time,18F-FDG dosages and glucose concentrations.The LDH activity,cellular ATP level and lactic acid concentration in cell supernatant of T47D-TamR and T47D cells were detected.Western blot was used to examine the expression of ERα,Glut-1,phosphorylated AMPK (p-AMPK) and phosphorylated mTOR (p-mTOR).Two-sample t test and two-way analysis of variance were used to analyze the data.Results T47D-TamR cell line was successfully established and its drug RI was 1.97±0.08,with a significantly decreased cell proliferation efficacy (F =230.10,P＜ 0.05).Significant differences of 18 FFDG uptake rates were found between T47D-TamR cell and T47D cell when changing the cell count,reaction time,and 18F-FDG dosage (F values419.00-1 116.00,all P＜0.05).The LDH activities of T47D cell and T47D-TamR cell were (0.42±0.04) and (0.32±0.02) U/mg protein,cellular ATP levels were (19.99±0.32) and (14.01±0.70) nmol/mg protein,lactic acid concentrations in cell supematant were (2.95±0.05) and (2.02±0.07) mmol/L,respectively.The differences of above parameters between the two groups were significant (t values4.39-18.80,all P＜0.05).The relative expressions of ERα,p-AMPK,pmTOR,Glut-1 were 0.26±0.03,0.36±0.06,0.75±0.11,0.35±0.07 in T47D cell,and 0.17±0.02,0.61±0.09,0.52±0.08,0.21±0.04 in T47D-TamR cell,and there were significant differences (t values12.20-16.45,all P＜0.05) between the two groups.Conclusions Compared with parental cells,T47D-TamR cells have lower 18F-FDG uptake rate,LDH activity,cellular ATP level and lactic acid concentration,increased p-AMPK expression and decreased ERα,p-mTOR,Glut-1 expression,indicating the decreased glycolysis ability in TAM-resistant breast cancer cells.