Figure 4.

Osteopontin (OPN) is a target of Iroquois homeobox gene 5 (IRX5). A, mRNA level of OPN in IRX5 overexpressed CAL27 cell. B, Protein level of OPN in IRX5 overexpressed CAL27 cell. C, E, mRNA level of OPN in IRX5 down‐regulated CAL27 cell. D, F, Protein level of OPN in IRX5 down‐regulated CAL27 cell. G, OPN relative luciferase activity. OPN‐promoter: nucleotides, nts −2284 to −378 constructed into pGL3‐basic. Overexpression of IRX5 level elevated OPN promoter luciferase activity. H, Western blot analysis of OPN protein level down‐regulated by siRNA against OPN (siOPN#1, siOPN#2) compared with a nonsense control (siNC) in IRX5 overexpressed CAL27 cell. I, Down‐regulated OPN resulted in decreased proliferation rate of CAL27/IRX5 cell. J, mRNA level of cyclinD1 was decreased in CAL27/IRX5 cell when down‐regulating OPN expression. K, Transwell assay analysis of the ability of migration and invasion of IRX5 overexpressed CAL27 cell blocked by siOPNs. *P < .05, **P < .01, ***P < .001. Error bars represent the mean ± SD values