Enhancement of radiosensitivity in human glioblastoma U138MG cells by tetrandrine

Tetrandrine, a natural lipid-soluble alkaloid with a tow molecular weight, has both anti-tumor activity and a tissue-protective effect, as demonstrate d in our previous studies. We studied tetrandrine to determine whether or n ot it enhanced radiosensitivity in human glioblastoma U138MG cells. Tetrand rine 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 elim inated the cell cycle perturbation induced by radiation. Cells treated with tetrandrine alone as well as with a combination of tetrandrine and radiati on became rounded, floated up and grew sparsely under observation under an inverted light microscope, DNA fragmentation was also noted by gel electrop horesis. These findings suggest that tetrandrine has potential as an adjunc t to radiotherapy for glioblastoma.