Open Access

Sarah Thaler

• Sulforaphane is a natural substance found in cruciferous vegetables such as broccoli or cabbage. There are promising results for a number of tumor entities regarding the potential anti-carcinogenic effects of sulforaphane. The experiments designed for this study were performed on prostate carcinoma cells. The aim was to investigate the influence of sulforaphane on the growth behaviour of prostate cancer cells. Designed as an in-vitro-model, prostate carcinoma cell lines DU145 and PC3 were used in the study. The experiments can be roughly divided into two categories: • Regulation of cell growth: After the growth inhibitory effect of sulforaphane has been confirmed (MTT test), the proliferation rate (BrdU assay) and apoptosis rate (apoptosis assay) of the cells were measured under the influence of sulforaphane. Studies on clonogenic growth completed this series of experiments. • Regulation of the cell cycle: After determining the impact of sulforaphane on the phases of the cell cycle (cell cycle assay), the cell cycle-relevant proteins of the cyclin-CDK-axis, the CDK inhibitors p19 and p27 as well as the acetylated histones aH3 and aH4 were analysed (Western Blot). An additional MTT test was performed to determine a possible induction of resistance by long-term sulforaphane exposure. In addition, the expression profile of CD44 subtypes v4, v5 and v7 under the influence of sulforaphane has been investigated by FACS analysis. The growth and proliferation rate as well as the clonogenic growth of the prostate carcinoma cells were shown to be inhibited under the influence of sulforaphane in a concentration-dependent manner. Induction of apoptosis has not occurred. The treatment with sulforaphane resulted in a concentration-dependent G2/M arrest of the cell cycle. The level of expression of cyclins A and B and of CDKs 1 and 2 has increased due to sulforaphane exposure. The level of expression of pCDKs has decreased except for a slight increase in pCDK 2 in the DU145 cell line. The CDK inhibitors p19 and p27 were elevated, except for a reduction of p27 in the PC3 cell line. The level of expression of acetylated histones aH3 and aH4 has increased due to sulforaphane treatment. Indications for induction of resistance by long-term use of sulforaphane were not found. Treatment with sulforaphane resulted in an increased expression level of the CD44 subtypes v4, v5 and v7 in a concentration- and time-dependent manner. The test results fit into the existing findings. The exact processes and relationships of the modes of action are not yet sufficiently understood. Nevertheless, it can be stated that sulforaphane can trigger anticarcinogenic mechanisms at the molecular level also in prostate cancer. Therefore, sulforaphane could eventually be used in clinical practice, whether prophylactically or therapeutically. Further studies, also in clinical settings on humans, are therefore necessary.