Apoptosis-Mediated Proliferation Inhibition of Human Breast Cancer Cells by Lemon Citrus Extract

Abstract

Dietary phytochemicals have a variety of antitumor properties. In the present study, the antitumor activity of a methanolic extract of lemon fruit (lemon extract; LE) on the MCF-7 breast cancer cell line was investigated in vitro. Apoptotic cell death was analyzed using the TUNEL assay. In addition, the apoptosis mediated by LE in the MCF-7 cells was associated with the increased expression of the tumor suppressor p53 and caspase-3. Additionally, the expression of a pro-apoptotic gene, bax, was increased, and the expression of an anti-apoptotic gene, bcl-2, was decreased by LE treatment, resulting in a shift in the Bax:Bcl-2 ratio to one that favored apoptosis. The expression of a major apoptotic gene, caspase-3, was increased by LE treatment. In light of the above results, we concluded that LE can induce the apoptosis of MCF-7 breast cancer cells via Bax-related caspase-3 activation. This study provides experimental data that are relevant to the possible future clinical use of LE to treat breast cancer.