Apoptosis-mediated inhibition of human breast cancer cell proliferation by lemon citrus extract

Asian Pac J Cancer Prev. 2011;12(6):1555-9.


Dietary phytochemicals have a variety of antitumor properties. In the present study, the antitumor activity of methanolic extract of lemon fruit (lemon extract; LE) (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 extract 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 extract 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 extract treatment. In light of the above results, we concluded that LE extract 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Caspase 3 / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / drug effects*
  • Citrus*
  • Female
  • Humans
  • Plant Extracts / pharmacology*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Tumor Suppressor Protein p53 / metabolism
  • bcl-2-Associated X Protein / metabolism


  • BAX protein, human
  • Plant Extracts
  • Proto-Oncogene Proteins c-bcl-2
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • bcl-2-Associated X Protein
  • CASP3 protein, human
  • Caspase 3