Evaluate The Early Effects Of PI3K Signaling Pathway Inhibitor Combined With Tamoxifen On Human Breast Carcinoma By ¹⁸F-FDG

Objective To investigate the effects of PI3 K signaling pathway inhibitor LY294002 on human breast cancer cell T47 D with tamoxifen in vitro. To evaluate the early effects by 18F-FDG.Methods T47 D cells were inoculated in 96-well flat-bottomed plates, the MTT assays were taken to measure the rates of inhibition at the 24th/48 th hour after administration of TAM and/or LY294002 in different concentrations. T47 D cells were inoculated in 6-well flat-bottomed plates, after treated with TAM and/or LY294002 in different concentrations(0, TAM-IC50, LY-IC50, low concentration of TAM combine with LY, low concentration of TAM and low concentration of LY) in 24th/48 th hour, the apoptosis and cell cycle distribution of T47 D cells were evaluated by the flow cytometer. The uptake rates of 18F-FDG were measured at the 24th/48 th hour after administration of TAM and/or LY294002 in different concentrations.Results 1.MTT results showed that cell proliferation inhibition rates were rise with the increase of drug concentration. When TAM/LY294002 treated T47 D cells alone, the TAM-IC50 were 20 × 10-6mol/L; the LY-IC50 were 40 × 10-6mol/L. The cell growth inhibition rates were higher when TAM and LY combined in a low concentration.2.The apoptosis were(5.32±0.35)% /(10.2±1.13)%,(39.44±2.25)% /(45.6±1.56)%,(24.02±4.22)% /(30.05±2.7)%,(8.31±0.45)% /(12.81±2.24)%,(6.64±1.91)% /(14.97±1.39)%,(12.33±1.08)% /(21.27±1.13)% at the 24th/48 th hour after administration of 0, TAM-IC50, LY-IC50, low concentration of TAM, low concentration of LY and low concentration of TAM combine with LY. That is, the low concentration could make more apoptosis when TAM and LY were combined(P<0.05).3.After treated with different concentrations in 48 th, the G2/M phase of T47 D cells asfollows:(3.57±1.78)%,(4.11±1.72)%,(34.05±1.95)%,(4.09±1.68)%,(11.79±3.0)%,(12.5±1.08)%. The G2/M phase cells proportion was higher when TAM and LY were combined(P<0.05).4.The uptake inhibition rates of 18F-FDG were(42.79±6.52)% /(44.67±3.44)%,(25.72±6.40)% /(26.29±5.62)%,(13.84±4.85)% /(13.07±4.32)%,(12.65±3.69)% /(11.66 ± 5.08)%,(22.70 ± 1.76)% /(26.87 ± 8.20)% at the 24th/48 th hour after administration of TAM-IC50, LY-IC50, low concentration of TAM, low concentration of LY and low concentration of TAM combine with LY. The uptake inhibition rate was higher when TAM and LY were combined(P<0.05).Conclusion The cell growth inhibition rate, level of apoptosis, the G2/M phase cells proportion and the uptake inhibition rate of 18F-FDG were increased when PI3 K signaling pathway inhibitor LY294002 combined with TAM on human breast cancer cell T47 D.18F-FDG could evaluate the early effects of PI3 K signaling pathway inhibitor combined with tamoxifen on breast cancer cell T47 D.