TP53 and prostate cancer: Moreover, when the prostate cancer cell lines C4-2B and PC-3 were placed in the upper chamber and the MC3T3-E1 pre-osteoblasts cells in the lower chamber (as a stimulant in a standard transwell chemotaxis assay), we found that overexpression of TP53 reduced, while ablation of TP53 increased the chemotaxis of prostate cancer cells toward the osteoblasts in the lower compartment (Figure 2B).