Effect of Asiaticoside on 99mTc-Tetrofosmin and 99mTc-Sestamibi Uptake in MCF-7 Cells

Abstract

This study was done to examine the effect of asiaticoside on MCF-7 cell uptake of (99m)Tc-tetrofosmin ((99m)Tc-Tfos) and (99m)Tc-sestamibi ((99m)Tc-MIBI). The 3-(4,5-dimethylthiozol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the effect of a 50% inhibitory concentration of asiaticoside on MCF-7 cell proliferation. MCF-7 cells were treated with 10, 20, 30, 40, and 50 μM asiaticoside for 48 h and then incubated with 59.2 MBq of either (99m)Tc-Tfos or (99m)Tc-MIBI tracer for 60 min. The uptake of the tracers was measured with a dose calibrator. The 50% inhibitory concentration of asiaticoside for MCF-7 cells was determined with the MTT assay to be 40 μM. The uptake results were expressed as the mean ± SE radioactivity in MBq/mg of protein, and P values were also calculated (P values of 0.03 indicated significant differences). In the control (no asiaticoside) and at 10, 20, 30, 40, and 50 μM asiaticoside, the mean levels of (99m)Tc-Tfos uptake were 0.79 (SE, 0.059) (P = 0.14), 0.84 (SE, 0.057) (P = 0.60), 0.47 (SE, 0.034) (P = 0.03), 0.40 (SE, 0.050) (P = 0.03), 0.37 (SE, 0.050) (P = 0.03), and 0.15 (SE, 0.023) (P = 0.03), respectively; the mean levels of (99m)Tc-MIBI uptake were 0.95 (SE, 0.007) (P = 0.14), 0.81 (SE, 0.009) (P = 0.60), 0.79 (SE, 0.019) (P = 0.03), 0.63 (SE, 0.004) (P = 0.03), 0.13 (SE, 0.006) (P = 0.03), and 0.07 (SE, 0.008) (P = 0.03), respectively. Asiaticoside concentrations of 10, 20, 30, 40, and 50 μM revealed the uptake kinetics for both (99m)Tc-Tfos and (99m)Tc-MIBI in MCF-7 cells. (99m)Tc-Tfos and (99m)Tc-MIBI showed similar trends; the radioactivity uptake was dose dependent, and asiaticoside inhibited 16% and 47% of (99m)Tc-Tfos uptake and (99m)Tc-MIBI uptake in MCF-7 cells, respectively. This study showed that asiaticoside, acting as a biochemical modulator, may induce apoptosis and enhance antitumor activity in MCF-7 cells, as determined by (99m)Tc-Tfos and (99m)Tc-MIBI uptake. These findings are promising for cancer chemotherapy. Future studies should be performed to confirm our findings and to further delineate the clinical role of asiaticoside.