Phloroglucinol suppresses metastatic ability of breast cancer cells by inhibition of epithelial-mesenchymal cell transition

Cancer Sci. 2015 Jan;106(1):94-101. doi: 10.1111/cas.12562. Epub 2014 Dec 3.


Metastasis is a challenging clinical problem and the primary cause of death in breast cancer patients. However, there is no therapeutic agent against metastasis of breast cancer cells. Here we report that phloroglucinol, a natural phlorotannin component of brown algae suppresses metastatic ability of breast cancer cells. Treatment with phloroglucinol effectively inhibited mesenchymal phenotypes of basal type breast cancer cells through downregulation of SLUG without causing a cytotoxic effect. Importantly, phloroglucinol decreased SLUG through inhibition of PI3K/AKT and RAS/RAF-1/ERK signaling. In agreement with in vitro data, phloroglucinol was also effective against in vivo metastasis of breast cancer cells, drastically suppressing their metastatic ability to lungs, and extending the survival time of mice. Collectively, our findings demonstrate a novel anticancer activity of phloroglucinol against metastasis of breast cancer cells, implicating its clinical relevance.

Keywords: SLUG; basal type breast cancer cells; cancer metastasis; epithelial-mesenchymal transition; phloroglucinol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Agents / therapeutic use
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / pathology
  • Cell Movement
  • Epithelial-Mesenchymal Transition / drug effects*
  • Female
  • Humans
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / secondary
  • MAP Kinase Signaling System
  • Mice, Inbred BALB C
  • Mice, Nude
  • Neoplasm Invasiveness
  • Phloroglucinol / pharmacology*
  • Phloroglucinol / therapeutic use
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Xenograft Model Antitumor Assays


  • Antineoplastic Agents
  • Phloroglucinol
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt