Effect of free radicals on the biological action of genistein in vitro and synergism with mitomycin C.

BACKGROUND

The effect of oxidizing and reducing free radicals on the biological properties of genistein (GEN) were investigated in vitro.

MATERIALS AND METHODS

MCF-7 cells were treated with GEN (5 micromol or 40 micromol) and/or mitomycin C (MMC; 2.5 micromol). For testing a possible radiosensitizing and synergistic effect of GEN in relation to MMC, a radiation dose of gamma-rays was applied up to 8 Gy. In order to produce the desired free radicals, the media were saturated with: (i) air (46% OH and 54% O2(*-)), (ii) N2O (90% OH, 10% H), or (iii) argon (44% e(-)(aq), 10% H and 46% OH). The survival fractions of the cells were determined by clonogenic assay.

RESULTS AND CONCLUSION

GEN was found to be able to sensitize MCF-7 cells against the action of reducing (e(-)(aq), H, R()) as well as of oxidizing (OH, O2(-)) free radicals. This ability was enhanced with increasing GEN concentration. Moreover, GEN acted synergistically with MMC in reducing as well as in oxidizing environments.