Xenografts of human pluripotent stem cells and embryonal carcinoma cells

Here we perfomed the Teratoma assay for a normal human embryonic stem cell line (H9(+Dox)), a human embryonic stem cell line with a mesendodermal differentiation bias (H9Hyb), a normal human induced pluripotent stem cell line (LU07), a human induced pluripotent stem cell line with reactivated transgenes (LU07+Dox) and a human embryonal carcinoma cell line (EC) and anayzed their gene expression. The ability to form teratomas in vivo containing multiple somatic cell types is regarded as functional evidence of pluripotency for human pluripotent stem cells (hPSCs). Since the Teratoma assay is animal-dependent, laborious and only qualitative, the PluriTest and the hPSC ScoreCard assay have been developed as in vitro alternatives. Here we compared normal hPSCs, induced hPSCs (hiPSCs) with reactivated reprogramming transgenes and human embryonal carcinoma (hEC) cells in these assays. While normal hPSCs gave rise to typical teratomas, the xenografts of the hEC cells and the hiPSCs with reactivated reprogramming transgenes were largely undifferentiated and malignant. The hPSC ScoreCard assay confirmed the line-specific differentiation propensities in vitro. However, when undifferentiated cells were analysed with PluriTest only hEC cells were identified as abnormal whereas all other cell lines were indistinguishable and resembled normal hPSCs. Our results indicate that pluripotency assays are best selected on the basis of intended downstream applications. Total RNA from 1-3 xenografts were analyzed