A Yazdani Movahed - Department of Developmental Biology, Faculty of Sciences andAdvanced Technologies in Biology, University of Science and Culture,Tehran, Iran . Department of S tem Cells and Developmental Biology, Cell ScienceResearch Center, Royan Ins titute for S tem Cel
H Torkian - Department of Developmental Biology, Faculty of Sciences andAdvanced Technologies in Biology, University of Science and Culture,Tehran, Iran . Department of S tem Cells and Developmental Biology, Cell ScienceResearch Center, Royan Ins titute for S tem Cel
SH Moradi - Department of S tem Cells and Developmental Biology, Cell ScienceResearch Center, Royan Ins titute for S tem Cell Biology andTechnology, ACECR, Tehran, Iran

Objective: Human embryonic s tem cells (ESCs) hold great promise for regenerative medicine. However, there is a potentialtumorigenicity associated with the residual undifferentiatedESCs. The enhancement of the RNAi pathway has been foundto be detrimental to tumorigenesis. Here, we aim to exploit thepotential of two RNAi enhancers, ciprofloxacin and ofloxacin,to inhibit the growth of undifferentiated ESCs, thereby ensuringthe safety of ESC-based cell therapy.Materials and Methods: The human ESC line Royan H۶ wascultured in DMEM/F۱۲, ۲۰% KOSR, ۱% ITS, ۱% non-essentialamino acids, and ۱% L-Gln in the presence of bFGF (۱۲.۵ng/ml). Human dermal fibroblas ts (HDFs) were maintained inhigh-Glc DMEM and ۱۵% FBS. To examine the effect of ciprofloxacinand ofloxacin (both, ۱۲۴ μM) on the cells, we usedphase-contras t imaging, MTT viability assays, and Live/Deads taining.Results: The phase-contras t imaging revealed that both ciprofloxacinand ofloxacin decreased the growth of human ESCs.In contras t, the growth of HDFs remained intact in response tothe treatments. In addition, our MTT assays indicated that bothchemicals sharply reduced the viability of human ESCs as opposedto HDFs. Finally, we confirmed the diminished viabilityof human ESCs upon treatment with ciprofloxacin and ofloxacinusing Live/Dead analysis. Notably, no inhibitory effects onthe HDF viability were observed pos t-treatment, as evidencedby a large number of live (green) cells in both the treated anduntreated groups.Conclusion: The RNAi enhancers ciprofloxacin and ofloxacinexert a potent suppressive impact on the growth of human ESCsbut not fibroblas ts.

Cell Death, Fluoroquinolone, Pluripotency, Teratoma,S tem Cell Therapy