The absorptance values were analyzed using one-way ANOVA and the differences between the cells that stably expressing shGRP78-3 and control cells were significant (p < 0.05), suggesting that GRP78 knockdown decreased the expression levels of MMP-2, MMP-9, MMP-14 and TIMP-2 in SMMC7721 cells (Figure 4B and 4C). We further analyzed whether Grp78 knockdown affected the activity of MMP2 and MMP9 by gelatin-zymography assay. As shown in Figure 4D and 4E, the

activity Trichostatin A manufacturer of MMP-2 in C3 and C4 cells was significantly lower than that in parental and vector transfected cells, The absorptance values were analyzed by one-way ANOVA and the differences between the cells that stably expressing shGRP78-3 and control cells were significant (p < 0.05). However, we do not detect the activity of MMP-9 in parental, vector, C3 and C4 cells. Taken together, our findings demonstrate that GRP78 knockdown inhibites the ECM degradation by decreasing the expression and activity of MMP-2. Figure 4 GRP78 knockdown decreased ECM degradation. (A) FITC-gelatin degradation analysis of the extracellular matrix degradation capability of the cells that stably expressing shGRP78-3.

The experiments were repeated for three times. (B) Western blot analysis of MMP-2,MMP-9,MMP-14 and TIMP-2 expression in the cells that stably expressing shGRP78-3, and the results of quantative analysis were represented as ± SE and analyzed by one-way ANOVA (Columns,mean of three separate experiments; bars, SE; *, values significantly different at the 5% levels). (C) and (D) Gelatin zymograph analysis of the MEK162 activities PS-341 clinical trial of MMP-2 and MMP-9 in GRP78 knockdown cells. The activities of MMP-2 and MMP-9 were represented as ± SE and analyzed by one-way ANOVA (Columns,mean of three separate experiments; bars, SE; *, values significantly different at the 5%

levels). GRP78 knockdown decreased JNK and ERK signaling pathway We then sought to determine the mechanisms underlying the reduction of MMPs activities caused by GRP78 knockdown in SMMC7721 cells. For the important roles of ERK1/2 and JNK in the regulation of MMP-2 and MMP-9 activities, we examined the phosphorylation Montelukast Sodium levels of ERK1/2 and JNK in C3 and C4 cells using western blot. As shown in Figure 5A and B, the p-ERK1/2 and p-JNK levels were reduced as compared with control cells. The values were analyzed by one-way ANOVA and the differences between C3 or C4 cells and control cells were significant (p < 0.05). Because the activities of ERK1/2 and JNK were modulated in large part by FAK-Src signaling pathway [22], we examined the phosphorylation levels of FAK at Y397 and Src at Y416 in C3 and C4 cells. We found that GRP78 knockdown significantly decreased the levels of pY397-FAK and pY416-Src in SMMC7721 cells (p < 0.05) (Figure 5C).