Fig 2: Cell-cycle analysis of KIF14 knockdown cells. (A) Flow cytometric analysis was performed to investigate the cell cycle in shKIF14 and shMock cells. The percentage of the G2/M phase in shKIF14 cells (Ho-N-1- and SAS-derived transfectants; 2 clones each) has increased markedly compared with the shMock cells (P<0.05, Mann–Whitney U-test). (B) shKIF14 cells show up-regulation of p-Cdc2 and cyclin B1 (Ho-N-1- and SAS-derived transfectants; 2 clones each) compared with shMock cells (P<0.05, Mann–Whitney U test).

Fig 3: Establishment of KIF14 knockdown cells and cellular proliferation of KIF14 knockdown cells. (A) qRT-PCR shows that KIF14 mRNA expression in the shKIF14 cells (Ho-1-N-1-and SAS-derived transfectants; 2 clones each) is significantly (P<0.05, Mann–Whitney U-test) lower than in the shMock cells. (B) Immunoblotting analysis shows that the KIF14 protein levels in shKIF14 cells (Ho-N-1- and SAS-derived transfectants; 2 clones each) also have decreased markedly compared with that in the shMock cells. (C) To determine the effect of shKIF14 on cellular proliferation, shKIF14 and shMock cells were seeded in six-well plates at a density of 1×104 viable cells/well. Both transfectants were counted on seven consecutive days. The cellular growth of shKIF14 cells (Ho-1-N-1- and SAS-derived transfectants; 2 clones each) are significantly (P<0.05, Mann–Whitney U test) inhibited compared with the shMock cells after 72 (Ho-1-N-1) and 96 (SAS) hours. The results are expressed as the means±SEM of values from three assays.

Fig 4: Evaluation of KIF14 expression in OSCC-derived cell lines. (A) Quantification of KIF14 mRNA expression in OSCC-derived cellular lines by qRT-PCR analysis. Significant up-regulation of KIF14 mRNA is seen in eight OSCC-derived cellular lines compared with the HNOKs (P<0.05, Mann–Whitney U-test). Data are expressed as the means±SEM of triplicate results. (B) Immunoblotting analysis of KIF14 protein in the OSCC-derived cell lines and HNOKs. KIF14 protein expression is up-regulated in the OSCC-derived cell lines compared with that in the HNOKs. Densitometric KIF14 protein data are normalized to GAPDH protein levels.