Down-regulation of deacetylase HDAC6 inhibits the melanoma cell line A375.S2 growth through ROS-dependent mitochondrial pathway

PLoS One. 2015 Mar 16;10(3):e0121247. doi: 10.1371/journal.pone.0121247. eCollection 2015.


Previous studies have shown that histone deacetylase 6 (HDAC6) plays critical roles in many cellular processes related to cancer. However, its biological roles in the development of melanoma remain unexplored. Our aim was to investigate whether HDAC6 has a biological role in human melanoma development and to understand its underlying mechanism. In the present study, HDAC6 expression was up-regulated in melanoma tissues and cell lines. Knockdown of HDAC6 significantly inhibited the proliferation and colony formation ability of A375.S2 cells, promoted cell arrest at G0/G1 phase and apoptosis. Additionally, western blotting assay showed that HDAC6 silencing suppressed Bcl-2 level and enhanced Bax level, then activated caspase-9 and caspase-3, and further activated the release of cytochrome c from mitochondria to cytoplasm, finally induced cell apoptosis involving the mitochondrial pathway. Knockdown of HDAC6 triggered a significant generation of ROS and disruption of mitochondrial membrane potential (MMP). Furthermore, ROS inhibitor, NAC reduced HDAC6 siRNA-induced ROS production, and blocked HDAC6 siRNA-induced loss of MMP and apoptosis. NAC also significantly blocked HDAC6 siRNA-induced mtDNA copy number decrease and mitochondrial biogenesis and degradation imbalance. In conclusion, the results showed that knockdown of HDAC6 induced apoptosis in human melanoma A375.S2 cells through a ROS-dependent mitochondrial pathway.

MeSH terms

  • Apoptosis / genetics
  • Cell Cycle Checkpoints / genetics
  • Cell Line, Tumor
  • Cell Proliferation
  • Cellular Senescence / genetics
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic*
  • Gene Silencing
  • Histone Deacetylase 6
  • Histone Deacetylases / genetics*
  • Histone Deacetylases / metabolism
  • Humans
  • Matrix Metalloproteinases / metabolism
  • Melanoma / genetics*
  • Melanoma / metabolism*
  • Mitochondria / metabolism*
  • RNA Interference
  • RNA, Small Interfering / genetics
  • Reactive Oxygen Species / metabolism*
  • Signal Transduction*
  • Tumor Stem Cell Assay


  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Matrix Metalloproteinases
  • HDAC6 protein, human
  • Histone Deacetylase 6
  • Histone Deacetylases

Grant support

The authors have no support or funding to report.