CS1 fibronectin enhances spreading of SCC cells (HSC-3 and UM-SCC14A). (A and B top panel) cells were incubated in serum free media containing scramble peptide (Scr1, and Scr2), CS1 peptide or CS1 blocking peptide as indicated for 3 h and photographed (X200). (C top panel) Cells were cultured in 96 plates coated with Scr-BSA, CS1-BSA or CS1 blocking-BSA (VLA4 inhibitor) as indicated for 3 h and photographed (X200). (A, B and C bottom panel) The percentage of SCC cell spreading under these different conditions was quantified and illustrated. D. Integrin α4 suppression inhibits CS1-mediated cell spreading. Percentage of spreading after transfected with integrin α4 siRNA or the control siRNA and plated in a CS1-BSA (40 μg/ml) or Scr-BSA (40 μg/ml) coated wells. Inset, Immunoblot showing integrin α4 expression in cells transfected with control or integrin α4 siRNA (100 pM). Data represent mean ± SD from three independent experiments *, # p < 0.05.