Both drugs effectively decreased Smad6 expression and increased p‐Smad3‐Rho‐ROCK‐MLC signalling levels in HUVECs pre‐incubated with BMP9‐overexpressing HBV‐infected cells to a level similar to that in HUVECs pre‐incubated with HBV‐infected hepatoma cells (Figure 5D, Supporting Information Figure S4B). Here, SMAD3 is linked to hepatocellular carcinoma.