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. 2009 Mar 16;4(3):e4849. doi: 10.1371/journal.pone.0004849

Figure 2. Intracellular expression of endogenous FOXM1 protein in primary cultures of human normal oral mucosa (NHOK1), dysplasia (DOK) and HNSCC (UK1).

Figure 2

(A) Fluorescence images showing intracellular localisation of FOXM1 (green) in respective cells counterstained by a nuclear-stain DAPI (blue). The bottom panels are FOXM1 and DAPI merged images of high-power magnification (×400) showing nuclear localisation of FOXM1 protein. (B) Histogram of FOXM1 protein expression levels in 50 cells analysed arranged from low to high FOXM1 levels. (C) Mean FOXM1 protein expression levels in HNOK1, DOK and UK1 cells, n = 50 cells analysed in (B). (D) Immunoblotting for endogenous FOXM1 protein in normal (NHOK1 and NHOK355), dysplasia (POE9n and D20) and HNSCC (CaLH2, CaDec12, UK1 and 5PT) cell lines as indicated. β-Tubulin was immunoblotted for loading control in each sample. (E) Serum starvation (24 h) did not alter the endogenous FOXM1B mRNA levels in primary NHOK1, premalignant POE9n or UK1 HNSCC cells. (F) qPCR data showed that known FOXM1B target genes such as CENPF, CENPA, NEK2 and cyclin B1 are upregulated in UK1 compared to NHOK1 cells. *(P<0.05), **(P<0.01) and ***(P<0.001) indicate significant increase in FOXM1 protein levels when compared to NHOK1 cells.