HSP70 activators induce cancer cell differentiation. (A) LNCaP cells were treated with DMSO, HMBA, 4a1 or SW02 using the indicated concentrations for 24 h. P21 expression was examined with western blot. The results are representative of three independent experiments and the representative one or the mean is presented (±SD). The densitometry measurement of the band intensities of three western blots were listed on the right. *P <0.01 vs. DMSO by unpaired t test. (B) LNCaP cells were treated with DMSO, HMBA, 4a1 or SW02 with indicated concentrations for 5 days, and images of cell morphology were taken (10 X objective, scan bar: 200 μm).