Fig. 1

a. In vitro growth of small cell carcinoma LuCaP 145.1. The photomicrographs show tumor cells after collagenase digestion and plating on MEF (scale bar = 200 μm). Expression monitoring of NANOG (electropherogram) showed in vitro growth to d21, and that the cells could be passaged (p2). The signals for d0 and d2 are included. λHindIII is the DNA size marker. b. Plasmid transfection of LuCaP 145.1. The photomicrographs show LuCaP 145.1 cells post-transfection (PENK and α-scTF vectors) under drug selection. Drug-resistant cells proliferated for 3 d (with lysed MEF in the background) before harvest. The electropherogram confirms that PENK+ cells (LuCaP 145.1/PENK) were neo⁺bsr⁻PENK⁺ while PENK– cells (LuCaP 145.1/α-scTF) were neo⁺bsr⁺PENK⁻. The neo signal provides control for sample loading since it was expressed by both PENK+ and PENK– cells. B2M is typically used to serve as a house-keeping gene marker but in this case it was differentially expressed between PENK+ and PENK– cells