Enhancement of radiosensitivity in human glioblastoma U138MG cells by tetrandrine.

Tetrandrine, a natural lipid-soluble alkaloid with a low molecular weight, has both anti-tumor activity and a tissue-protective effect, as demonstrated in our previous studies. We studied tetrandrine to determine whether or not it enhanced radiosensitivity in human glioblastoma U138MG cells. Tetrandrine at concentration of 5.0 and 7.5 eg/ml dramatically enhanced the growth-inhibiting effect of radiation. This effect is dose-dependent on the dose of both tetrandrine and radiation. Moreover, we found that tetrandrine eliminated the cell cycle perturbation induced by radiation. Cells treated with tetrandrine alone as well as with a combination of tetrandrine and radiation became rounded, floated up and grew sparsely under observation under an inverted light microscope, DNA fragmentation was also noted by gel electrophoresis. These findings suggest that tetrandrine has potential as an adjunct to radiotherapy for glioblastoma.