FIGURE 5.

Knockdown of S100A14 reduces HER2 phosphorylation and downstream signaling and HER2-stimulated cell proliferation. A, MCF-7 cells were transiently transfected with the ON-TARGETplus S100A14 pool siRNA or ON-TARGETplus non-targeting siRNA, and 24 h after transfection, the plasmid expressing FLAG or FLAG-HER2 was transfected into the cells. Equal amounts of protein were resolved by SDS-PAGE, transferred to PVDF membranes, and probed with anti-S100A14, anti-pHER2, anti-HER2, anti-pAKT, anti-AKT, anti-pERK, anti-ERK, and anti-β-actin antibodies. B, 24 h after ON-TARGETplus S100A14 pool siRNA or ON-TARGETplus non-targeting siRNA transfection, the plasmid expressing FLAG or FLAG-HER2 was transfected into the cells, and the viability of MCF-7 cells was measured using an MTS assay. *, p < 0.05; **, p < 0.01. C, siRNAs and plasmids were transfected into SK-BR3 cells according to the above method. The levels of pHER2, HER2, pAKT, AKT, pERK, ERK, and β-actin were detected. D, cell proliferation assay was performed in SK-BR3 cells. **, p < 0.01. E, siRNAs and plasmids were transfected into BT474 cells according to the above method. The levels of pHER2, HER2, pAKT, AKT, pERK, ERK, and β-actin were detected. F, cell proliferation assay was performed in BT474 cells. *, p < 0.05; **, p < 0.01. Error bars, S.D.