Objective: Prostate cancer is prevalent malignancy in men, and conventional therapies often exert dramatic side effects. Papaver somniferum extract exhibit promising anticancer properties with a potential for reducing adverse effects of cancer. This study aimed to evaluate the antiproliferative and cytotoxic effects of Papaver somniferum extract on Du145 prostate cancer cells and compare its efficacy with tamoxifen. Materials and Methods: IC50 of tamoxifen and Papaver somniferum extracts was determined on Du145 cells using the MTT (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Three groups were designed for this study: 1) control group (Du145 prostate cancer cell line was harvested in the flask without treatment), 2) the cell lines treated with IC50 of tamoxifen (37.53 ± 1.9 μg/mL), and 3) the cell lines treated with IC50 of Papaver somniferum extract (77.37 ± 2.7 μg/Ml) for 72 hours. Real-time PCR was used to assess changes in expression of CDK4 (cell cycle controlling and regulation), miR- 146a (suppressor of BRCA1 gene), and miR-22 (suppressor of P53). Data were analyzed using SPSS software and one-way ANOVA and expressed as means±SD , p<0.05 was considered significantly Results: After 72 hours, The IC50 values for tamoxifen and P. somniferum extract were 37.53 ± 1.9 μg/mL and 77.37 ± 2.7 μg/mL respectively. Tamoxifen showed more toxicity than P somniferum extract, with maximum effect at 72 hours. Both treatments significantly(p<0.05) reduced CDK4 expression and increased the expression of miR-22 and miR-146a compared to the control group, demonstrating their antiproliferative effects. Conclusion: both Papaver somniferum extract and tamoxifen showed anti-proliferative effects on Du145 prostate cancer cells and influenced autophagy-related gene expression. Although tamoxifen was more potent, the extract also showed significant activity, indicating its potential in cancer therapy. Further research is needed to identify active compounds, evaluate in vivo efficacy, and assess safety before clinical use.
