Curcumin inhibits the expression of ornithine decarboxylase and adenosine deaminase genes in MCF-7 human breast cancer cells

Curcumin is the active ingredient of Curcuma longa, which inhibits the development of malignant cells. Prevention and treatment of cancer by natural compounds, especially curcumin, and understanding the mechanism of action, is an area of interest in cancer research. In this study, we evaluated the effects of curcumin on cell proliferation, ornithine decarboxylase 1 (ODC1) and adenosine deaminase (ADA) gene expression in human breast cancer cell line (MCF-7) as compared to the non-cancer line (MCF-10A). Both cell lines were subjected to increasing doses of curcumin, ranging from 0 to 30 mu g/mL. Cell viability was quantified by the MTT assay. In vitro clonogenic survival assay was performed on MCF-7 cells. Expression of ADA and ODC1 were analyzed by Western blotting and qRT-PCR. Curcumin inhibited the growth of malignant cells in a time-and dose-dependent manner. The calculated IC50 value for MCF-7 cells in 48 h was 12 mu g/mL. Forty-five to 70% decreases in colony formation were observed in MCF-7 cells treated with 30-60 mu g/mL curcumin, respectively. Our data revealed a dose-dependent downregulation of ODC1 and ADA expression and respective enzyme activities by curcumin, which correlated with decreased proliferation in the MCF-7 breast cancer cell line. These data suggest that curcumin represses the proliferation of breast cancer cells through downregulation of ODC1 and ADA gene expression, which might be another mechanism of curcumin-mediated tumor growth inhibition.