Fig. 1

Notch1^C1133Y mutation inactivates the Notch1 signaling pathway. a Endogenous Notch1 expression in HNSCC cell lines (HN4, HN6, HN13 and CAL27) assessed by western blot analysis (up) and the quantification of the protein expression (down). b HN6 and CAL27 cells were transfected with pcDNA3.1-Notch1^WT, pcDNA3.1-Notch1^C1133Y, or pcDNA3.1 empty vector. 48 h later, Notch1 mRNA expression was detected by real-time qPCR. c In HN6 cells, Notch1 target genes HES1-2 mRNA expressions were determined by real-time qPCR after transfection. d Notch1 target genes were also tested in CAL27 cells after transfection. e Protein expression levels of HES1-2 and cleaved-NICD (or NICD) were determined by western blot after transfection