A) PC cells (5×103/well in 96-well plate) were treated with 0–50 nM Dtxl, SPION-Dtxl or respective control for 48 hrs and proliferative ability of cells was assessed by MTS assay. B) PC cells (500) were incubated with 0, 2.5, 5, and 10 nM Dtxl or equivalent SPION-Dtxl or respective controls (DMSO/SPION, represented as C). On Day 14, cells were PBS rinsed and stained with hematoxylin. Photographs of clonogenic pattern represent superior inhibition of clonogenic formulation with SPION-Dtxl.