In addition, miR-21 inhibition enhanced the suppressive effect of curcumin on TGF-β1/smad3 signaling pathway, while the silencing of TIMP3 has attenuated the effect of miR-21 inhibition, indicating that the inhibition of miR-21 enhances the effect of curcumin on cell proliferation inhibition and apoptosis in HCC cells by regulating TIMP3/TGF-β1/smad3 axis. Here, SMAD3 is linked to hepatocellular carcinoma.