FIGURE 4.

Gap junction protein Cx43 regulates CCN3 expression. A, Western analysis showing the reduction of Cx43 protein (shRNA-Cx43) in Hs578T breast cancer cells decreased CCN3 but not CCN1 protein expression. GAPDH was used as a loading control. B, Western analysis of the cell lysate and conditioned medium of Hs578T cells using anti-CCN3 and anti-Cx43 antibodies showing the level of Cx43 was not altered when CCN3 protein was eliminated with siRNA. siRNA against CCN3 had no effect on the smaller 25-kDa band that was also recognized by the CCN3 antibody in the cell lysate. Anti-GAPDH antibody was used as a loading control. C, quantification on the number of coupled cells per donor cells in Hs578T breast cancer cells is described under “Experimental Procedures.”