Figure 3. shRNA-mediated β-catenin knockdown is abolished at the protein but not mRNA level when K562^S cells are co-cultured in direct contact (DC) with HS-5 BM stromal cells.

a. Immunoblot analysis demonstrates restored β-catenin protein levels in K562^S-shβcat-expressing cells under conditions of co-culture in DC with HS-5 BM stromal cells (right, n=5). qRT-PCR confirmed maintenance of the knockdown at the mRNA level (left, n=2). Bars represent SEM and qRT-PCR data were normalized to expression of GUS. *p<0.05. b. shβcat increased apoptosis (left, n=3) and reduced colony formation (right, n=3) of K562^S cells cultured in regular medium (RM) or HS-5 conditioned medium (CM), but these effects were reduced or abolished when cultured in DC with HS-5 BM stromal cells. Bars represent SEM. *p<0.05. c. Immunoblot analysis demonstrates restored β-catenin protein levels in K562^S-shβcat-expressing cells under conditions of co-culture in DC with HS-23 and HS-27a BM stromal cells, which are closely related to the HS-5 cells used in these studies (n=2).