The interaction between beta-catenin, GSM3 beta and APC after motogen induced cell-cell dissociation, and their involvement in signal transduction pathways in prostate cancer

The effect of HGF/SF was examined on the interactions between APC, GSK3 bet a acid beta -catenin in prostate cancer cells LNCapFGC (E-cadherin positive ) and PC-3 (E-cadherin negative). Using immunoprecipitation, APC was found to be co-precipitated with either GSK3 beta or beta -catenin in both cell l ines. Stimulation with HGF/SF showed no change in the co-precipitation stat us of these protein molecules. In contrast, co-precipitation between GSK3 b eta and beta -catenin was only observed in LNCapFGC cells, and increased up on continued exposure to the motogen HGF/SF. Furthermore, using immunofluor escence, stimulation with HGF/SF was found to increase the level of co-loca lised cytoplasmic staining between beta -catenin and GSK3 beta, in prostate cancer cells. RT-PCR revealed that there were no mutations within the bind ing regions between beta -catenin and GSK3 beta. It is concluded, that unco mplexed cytoplasmic pools of beta -catenin associate more readily with the Axin complex in the absence of E-cadherin. Whereas, in the presence of E-ca dherin, beta -catenin is stabilised by forming tight cell-cell contacts whi ch may influence the invasive potential of cancer cells.