OBJECTIVETo explore the effect of the Hsp90 inhibitor anacardic acid on cell proliferation, invasion and migration of breast cancer MDA-MB-231 cells.

METHODSThe inhibitory effect of anacardic acid on Hsp90 was assessed with in vitro ATPase inhibition assay and ATP-sepharose binding assay. MTT assay was used to detect the growth inhibition induced by anacardic acid in MDA-MB-231 cells. Transwell assays were used to evaluate MDA-MB-231 cell invasion and migration. Western blotting was performed to assess the effect of anacardic acid in triggering the degradation of MMP-9, TIMP-1, Hsp90, and Hsp70.

RESULTSAnacardic acid exhibited a modest activity of ATPase inhibition with an IC50 value of 82.5 µmol/L. Anacardic acid significantly suppressed the proliferation of MDA-MB-231 cells in a dose-dependent manner (IC50 value of 29.3 µmol/L). Treatment with 12.5, 25, and 50 µmol/L anacardic acid for 36 h caused inhibition of cell invasion by 23.6%, 56.6%, and 67.0% in MDA-MB-231 cells, respectively (P<0.05), and anacardic acid treatment for 24 h inhibited the cell migration by 30.0%, 45.5%, and 77.5%, respectively (P<0.05). Anacardic acid dose-dependently induced MMP-9 degradation, but did not obviously affect Hsp90 or Hsp70 expressions.

CONCLUSIONAnacardic acid can significantly inhibit the proliferation, invasion, and migration of MDA-MB-231 cells, the mechanism of which may involve the inhibition of Hsp90 ATPse activity and down-regulation of MMP-9 expression.

Anacardic Acids ; pharmacology ; Breast Neoplasms ; pathology ; Cell Line, Tumor ; drug effects ; Cell Movement ; Cell Proliferation ; Down-Regulation ; HSP90 Heat-Shock Proteins ; antagonists & inhibitors ; metabolism ; Humans ; Matrix Metalloproteinase 9 ; metabolism ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism