Sulforaphane induces growth arrest and apoptosis in human ovarian cancer cells

Abstract

Objectives: Isothiocyanates (ITC) from broccoli and other cruciferous vegetables have long been shown to have chemopreventive properties, as demonstrated in cancer models in rodents. Sulforaphane (SFN) is a major ITC present in broccoli. We examined the effects of SFN on the growth of the OVCAR-3 and SKOV-3 ovarian carcinoma cell lines.

Methods: Cell cycle phase determination was performed using a Coulter flow cytometer. DNA strand breaks in apoptotic cells were measured by terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end-labelling (TUNEL).

Results: There was a concentration dependent decrease in cell density. Approximately 50% decrease was observed after 48 h of incubation with SFN (2 μM). Analysis of cell cycle phase progression revealed a decrease in the cell populations in S and G2M phases, with an increase of G1 cell population, indicating a G1 cell cycle arrest. The degree of decrease in the replicating population was concentration and time dependent. Incubation of OVCAR-3 cells in cultures with concentrations of 2, 10 and 50 μM of SFN showed 6, 8 and 17% apoptosis, respectively. In addition, when OVCAR-3 cells were exposed to SFN for various time periods (1, 2 or 3 days), the percentage of cells undergoing apoptosis was directly proportional to the incubation period. In this regard, while 18% of the cells underwent apoptosis after 2 days, 42% of the cells showed apoptosis after 3 days of incubation.

Conclusions: These results clearly demonstrated an effect of SFN in inducing growth arrest and apoptosis in ovarian carcinoma cell lines.