Cooperation of soluble CD147 and membrane-bound CD147 in the induction of MMP-2 in HCC cells. (A) Immunofluorescence of membrane-bound CD147 in SMMC-7721 cells, 7721-shCD147 cells, and T7721 cells detected by confocal laser scanning microscopy (×600). (B) The protein levels of CD147 and MMP-2 were analyzed by western blotting. Blots were probed for α-tubulin to ensure equal protein loading. Western blot scanning densitometry for three independent experiments. (C) The mRNA levels of CD147 and MMP-2 were analyzed by real-time PCR. (D) SMMC-7721 cells, 7721-shCD147 cells, and T7721 cells were treated with E-CD147ECD for 6 h and analyzed for CD147 and MMP-2 mRNA expression using real-time PCR. (E) Real-time RT-PCR detection of CD147 and MMP-2 mRNA levels in SMMC-7721 cells transfected with si-CD147 followed by stimulation with 10 μg/ml E-CD147ECD at different time points. Cells were transfected with snc-RNA as a control. GAPDH was used as a normalization control. *P < 0.05, **P < 0.01, ***P < 0.001.