Maintenance of Human iPSC Lines

The human iPS cell line 201B was provided by Dr. Shinya Yamanaka (Department of Life Science Frontiers, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan). 201B cells were maintained in tissue culture plates coated with recombinant human truncated vitronectin (Invitrogen, Carlsbad, CA) in Essential 8 medium (Invitrogen) supplemented with 10 μM ROCK inhibitor Y27632 (Invitrogen). Cells were routinely passaged as small clumps using the EDTA method with the split ratio of 1:8 to 1:12 every 2 to 3 days after reaching 60% to 80% confluence [31 (link)]. The human iPSC line ChiPS17 was purchased from TaKaRa (Shiga, Japan) and cultured using Cellartis DEF-CS Culture System (TaKaRa) according to the manufacturer’s instructions. Human fibroblast BJ and cancer cell lines (K562, HeLa and HEK293) were purchased from the Health Science Research Resources Bank (Osaka, Japan) and maintained in RPMI1640 or DMEM medium (Sigma-Aldrich, St. Louis, MO) supplemented with 10% heat-inactivated fetal calf serum (FCS) (Sigma-Aldrich).