Ectopic expression of DNA protein kinase (DNA-PK) inhibited metastasis-associated 1 (MTA1)-induced histone cluster 1 H1 family member c (H1.2) dephosphorylation and pro-oncogenic functions of MTA1. (A) Messenger RNA expression of DNA-PK was determined by PCR in HuH6 cells transfected with DNA-PK-HA expressing or pCMV-HA control plasmids. (B) Protein expression of DNA-PK was determined by Western blotting in HuH6 cells transfected with DNA-PK-HA-expressing or pCMV-HA control plasmids. (C) Western blotting in HuH6 cells cotransfected with pEGFP-MTA1 or pEGFP-N1 plasmids and DNA-PK-HA-expressing or pCMV-HA plasmids. (D,E) Transwell assays were performed in HuH6 cells transfected with pEGFP-MTA1 or pEGFP-N1 plasmids and DNA-PK-HA-expressing or pCMV-HA plasmids as indicated (MTA1, GFP, DNA-PK, or pCMV, respectively). Shown are representative images (D) and quantification of data obtained from three independent experiments (E). **P < 0.01, t-test. (F) Cell viability were detected in HuH6 cells transfected with pEGFP-K-MTA1G12V/T35S or pEGFP-N1 plasmids and DNA-PK-HA-expressing or pCMV-HA plasmids as indicated (MTA1, GFP, DNA-PK, or pCMV, respectively) and increasing amounts of DNA-PK-HA expressing plasmid were used (0.5, 1 μg). **P < 0.01, t-test. (G) Cell cycle progression was measured using flow cytometry in HuH6 cells transfected with pEGFP-K-MTA1G12V/T35S or pEGFP-N1 plasmids and DNA-PK-HA-expressing or pCMV-HA plasmids as indicated (MTA1, GFP, DNA-PK, or pCMV, respectively) and increasing amounts of DNA-PK-HA-expressing plasmid were used (0.5, 1 μg).