The RGD motif of TGFBI is necessary, but not sufficient, for adhesion of ovarian cancer cells expressing β3 integrin. A, Coomassie stained SDS-PAGE of purified wild-type, RGDmut, or YHmut of full-length recombinant TGFBI protein from bacteria. SKOV3 cells were replated on tissue culture wells coated with indicated constructs and allowed to adhere for 30 minutes. Results of three independent experiments were normalized to poly-L-lysine and represented as percent of fibronectin control. Significance of ***p < 0.001 is compared to full-length rTGFBI. B, SKOV3 cells pre-incubated with either the fibronectin RGD peptide (GRGDSP) or the TGFBI RGD peptide (ERGDEL) were replated on tissue culture wells coated with fibronectin or rTGFBI. Results of two independent experiments are represented as percent of control without peptide. Significance of *p < 0.05 is compared to no peptide control. C, Adhesion assays were performed with SKOV3 and PEO1 cells plated on poly-D-lysine, fibronectin, rTGFBI, or rTGFBI RGDmut. Results of two independent experiments were normalized to adhesion on poly-D-lysine and are represented as relative absorbance at 540 nm.