Expression and biological function of PlGF and Flt-1 in CRC cell lines. Quantitative PCR levels of Flt-1 (A) and PlGF (B) in CRC cell lines. The expression of SW480 was arbitrarily defined as the reference for comparison. (C) PlGF recombinant protein (10 ng/ml) increased the invasion ability in LoVo but not HT29 and HCT116 cells; (D) stable overexpression of PlGF increased the migration ability in LoVo and SW480 cells, but not in HT29 and HCT116 cells. PlGF level in the LoVo-PlGF (PlGF overexpressioin) cells was validated by quantitative RT-PCR (E), Western blot (F) (anti-PlGF at 200 ng/ml) and ELISA (G). The migration (H) and invasion (I) abilities increased in LoVo-PlGF cells as compared to LoVo-pcDNA, respectively. (Neg: negative control; Pos; positive control. * indicated as P < 0.05).