Soft agar colony formation by KB and KB-DEPDC1B cells and DEPDC1B-enhanced anchorage-independent growth was Rac1-dependent. (A) The upper panel presents relative colony size and the lower panel presents the quantitation of the results. The lower panel shows the ectopic DEPDC1B expression levels. (B) GTP loading in Rac1 was determined and the PAK PBD binding assay was used to analyze in KB or DEPDC1B-expressed KB cells in adherent and nonadherent cultured conditions. (C) Stable KB cell lines were seeded at an original density of 5000 cells per 6 well dishes, and the cell number was counted at the indicated time. (D) Stable KB cell lines were seeded at an original amount of 10 000 cells in a 50-mL conical tube with methylcellulose; cell numbers were counted at the indicated time. (E) Control KB and KB DEPDC1B-expressing cells stably transfected with Rac1 or Rac1N17were grown in soft agar. (F) DEPDC1B enhanced cell migration (M) and invasion (I) in KB cells.