Apoptotic activity of genistein on human lung adenocarcinoma SPC-A-1 cells and preliminary exploration of its mechanisms using microarray

Soy isoflavone genistein is active against certain solid malignancies, but its direct effect on lung adenocarcinoma and its mechanisms of action remain to be elucidated. In the present study, using the human lung adenocarcinoma cell line SPC-A-1, we found that genistein decreased SPC-A-1 cell viability in both a dose and time dependent manner. Flow cytometry analysis revealed that genistein significantly induced arrest of SPC-A-1 cells at the G2/M phase of the cell cycle. Furthermore, through DNA fragmentation and TUNEL assays, we demonstrated that the addition of genistein led to SPC-A-1 apoptosis in both a dose and time dependent manner. Finally, the apoptosis pathway-related gene expression profile affected by genistein was investigated using the oligonucleotide microarray method. The result showed that the expression profile of 20 genes (ratio of genistein group/control group >2 or <0.5) related to the apoptotic pathways changed. These genes, mainly consisting of the Bcl-2 family and TNF ligand and receptor family, are involved in regulation of the apoptosis process.