Identification of Histone Deacetylase 1 Protein Complexes inLiver Cancer Cells

Background: Hepatocellular carcinoma is one of the leading causes of mortalities worldwide. The searchfor new therapeutic targets is of utmost importance for improved treatment. Altered expression of HDAC1 inhepatocellular carcinoma (HCC) and its requirement for liver formation in zebrafish, suggest that it may regulatekey events in liver carcinogenesis and organogenesis. However, molecular mechanisms of HDAC1 action in livercarcinogenesis are largely unknown. The present study was conducted to identify HDAC1 interacting proteinsin HepG2 cells using modified SH-double-affinity purification coupled with liquid mass spectrophotemetery.Materials and
Methods: HepG2 cells were transfected with a construct containing HDAC1 with a C-terminalstrepIII-HA tag as bait. Bait proteins were confirmed to be expressed in HepG2 cells by western blotting andpurified by double affinity columns and protein complexes for analysis on a Thermo LTQ Orbitrap XL using a C18nano flow ESI liquid chromatography system.
Results: There were 27 proteins which showed novel interactionswith HDAC1 identified only in this study, while 14 were among the established interactors. Various subunits ofT complex proteins (TCP1) and prefoldin proteins (PFDN) were identified as interacting partners that showedhigh affinity with HDAC1 in HepG2 cells.
Conclusions: The double affinity purification method adopted in thisstudy was very successful in terms of specificity and reproducibility. The novel HDAC1 complex identified inthis study could be better therapeutic target for treatment of hepatocellular carcinoma.