FIGURE 5.

Various cell types differentiated from TK-hESCs (3IA) are insensitive to GCV. A, established teratomas formed by TK-hESCs are not sensitive to GCV. SCID mice were subcutaneously injected with hESCs and TK-hESCs around left and right hind legs, respectively. When teratomas were established after 6 weeks, mice were intraperitoneally injected with GCV (10 mg/kg/day) for 2 weeks. Mice were sacrificed, and teratomas were recovered. B, The mRNA levels of NANOG, OCT4, and TK in teratomas (indicated by −T) formed by both H9 hESCs and TK-hESCs with or without GCV treatment. The mRNA levels in the teratomas were determined by qPCR and compared with those in hESCs. Mean value are shown with S.D. (n = 3). C, cell lineages representing each of the three germ layers are presented in the established teratomas formed by TK-hESCs after GCV treatment as revealed by H&E staining. SE, squamous epithelium; R, rosette; PE, pigment epithelium; B, bone; C, cartilage; SM, smooth muscle; AT, adipose tissue; P, pancreas; GE, gut-like epithelium; SG, salivary gland. D, identification of cells of various lineages in the established teratomas formed by TK-hESCs after GCV treatment as revealed by immunostaining analyses. NeuN, neuronal marker; tropnin I, muscle marker. E, apoptotic cells in teratomas formed by TK-hESCs with or without GCV treatment as determined by TUNEL assay. The arrowheads indicate the apoptotic cells.