Immunodeficient nude mice

The procedure for assessing teratoma formation in nude mice was approved by the Animal Care and Use Committee of the Icahn School of Medicine at Mount Sinai. Undifferentiated hiPSCs (1 × 10⁶ cells) suspended with 100 μl of Matrigel (BD Biosciences, Franklin Lakes, NJ) were injected subcutaneously into 6–8 week-old Immunodeficient nude mice (Jackson Laboratories, Farmington, CT USA). Four weeks after injection, the formed teratomas were fixed with 10% formalin and processed for hematoxylin & eosin staining and histological evaluation.

Immunodeficient nude mice (Jackson Laboratory), 6–8-week-old, were first injected with 1 million human breast cancer cells (MDA-MB-231, ATCC) in the mammary fat pad to generate tumors. After 4 weeks of tumor development, sorted MDSC subpopulations were stained using PKH67 green fluorescent cell linker kit for general cell membrane labeling (Millipore Sigma) following the instructions suggested by the manufacturer. Tumor-bearing mice were then injected with ~2.5 × 10⁵ MDSCs via the tail vein. The mice were then collected 1-day post-injection, and the tumors, lungs and spleens were characterized with an IVIS Imaging System (Xenogen Imaging Technologies). All animal studies were performed in accordance with protocols approved by the Laboratory Animal Care and Use Committee of The Ohio State University.

Immunodeficient nude mice were purchased from Jackson Laboratories, USA. The procedure for assessing teratoma formation in nude mice was approved by the University of Cincinnati Animal Care And Use Committee. Undifferentiated miPSCs or miPSCs-p27 (1 × 10⁶ cells) were suspended with 100 μl of matrigel (BD) and were injected subcutaneously into 2- to 3-month-old nude mice. Four weeks after injection, teratomas were fixed with 10 % formalin and processed for hematoxylin and eosin staining for histological evaluation.