Figure 1.

HNSCC cell under hypoxic conditions underwent EMT phenotype and enhanced invasive behavior. A) Time course assay of 3 HNSCC cell lines growing under hypoxic conditions depict increased expression of HIF-1α compared with normoxic controls. Data represent means ± sem. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. B) HNSCC cell lines under hypoxic conditions presenting spindle-shaped phenotype compared with normoxic condition. Data represent means ± sem. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. C) Immunofluorescence for VIM of HNSCC cells cultured under hypoxia (24 h). Lower graphics depict the percentage of cancer cells expressing VIM under normoxia and hypoxia culture conditions. Data represent means ± sem. Scale bars, 100 μm. *P < 0.05, ***P < 0.001. D) Increased folds of tumor invasion of WSU-HN6 (2.56), WSU-HN12 (1.5), and WSU-HN13 (1.38) cell lines upon invasion assay under hypoxic conditions. E) Augmented invasion of hypoxic WSU-HN6, WSU-HN12, and WSU-HN13 cell lines compared with tumor cells invading in normoxia. Data represent means ± sem. *P < 0.05, ***P < 0.001. F) Quantification of the total number of viable tumor cells after 24 h of invasion at the upper and lower chambers (initial seeding density of 10⁴ cells). Note the higher number of WSU-HN6 tumor cells under hypoxia compared with the lower number of WSU-HN12 and WSU-HN13 cells compared with normoxic conditions. Data represent means ± sem. *P < 0.05, ****P < 0.0001. G) Schematic representation of the enhanced invasion of tumor cells during hypoxia.