Introduction: Prostate cancer is one of the most common cancers among men, with an increasing incidence and mortality rate. In the present study, cytotoxic and pro-apoptotic effects of spirulina platensis extract on PC-3 prostate adenocarcinoma cell line were investigated.
Methods: In the present experimental study, the PC-3 prostatic cancer cells were treated in four experimental   with 400, 200, 100 and 50 μg / ml extract of spirulina and incubated at 24 and 48 hours. Cytotoxicity was analyzed by MTS kit (3-(4, 5-Dimethylthiazol-2-yl)-5-(3-Carboxymethoxyphenyl)-2-(4-Sulfophenyl)-2H-Tetrazolium, Inner Salt) and apoptosis was analyzed by flow- cytometry using an Annexin V-FITC/PI kit according to the manufacturer protocol in both times. Statistical analysis was accomplished by ANOVA and Duncan tests using FlowJo and SPSS 16 software.
Results: In the experimental groups treated with extract of spirulina, the  viability of the cells showed a decrease compared to control group, while this decrease was more noticeable in the experimental group of 100 μg / ml at both incubation times (<0.0071).Increased incidence of apoptosis was significantly higher in the experimental groups than the control group. However, this increase was significantly higher than the control group at concentrations of 200 μg / ml in 24h incubation time (Ƥ < 0.0331) and 100 μg / ml of 48h incubation time (Ƥ < 0.0502).
Conclusion: Extract of Spirulina at specific concentrations reduced cell growth and induced apoptosis in PC-3 prostatic cancer cells. Evidence suggests that spirulina can be used as an anticancer drug for the treatment of prostate cancer.