Teratoma Formation by Human Embryonic Stem Cells Is Site Dependent and Enhanced by the Presence of Matrigel

Abstract

When implanted into immunodeficient mice, human embryonic stem cells (hESCs) give rise to teratoma, tumor-like formations containing tissues belonging to all three germ layers. The ability to form teratoma is a sine qua non characteristic of pluripotent stem cells. However, limited data are available regarding the effects of implantation site and the methods employed for implantation on the success rate of teratoma formation. In this study, the rate of teratoma formation in immunodeficient mice was site dependent: subcutaneous (25-100%), intratesticular (60%), intramuscular (12.5%), and under the kidney capsule (100%). Co-injecting the hESCs with Matrigel increased subcutaneous teratoma formation efficiency from 25-40% to 80-100%. We did not observe site-specific differences in the teratoma composition at the histological level. However, subcutaneous teratomas were quite distinct, easy to remove, and caused minimal discomfort to the mice. Also, subcutaneous teratomas displayed larger proportion of solid tissues as opposed to cyst formation that dominated the teratomas formed at the other sites. Interestingly, a chromosomally abnormal hESCs with trisomy 20 formed teratomas where the ratio of differentiated to undifferentiated tissues was significantly decreased suggesting defective pluripotency of the cells. In conclusion, subcutaneous implantation of hESCs in presence of Matrigel appears to be the most efficient, reproducible, and the easiest approach for teratoma formation by hESCs. Also, teratoma formation can be employed to study the development defects exhibited by the chromosomally abnormal hESC lines.

Taking stem cells to the clinic: Major challenges

“…Tumor formation in the lung and thymus had the highest probability of teratoma formation while the pancreas was partially siteprivileged [Shih et al, 2007]. More recently, Prokhorova et al, 2008] also demonstrated that the rate of teratoma formation with hESCs in immunodeficient mice was site-dependent (subcutaneous 25-100%; intratesticular 60%; intramuscular 12.5%; and under the kidney capsule 100%).…”

Enhanced differentiation of human embryonic stem cells to mesenchymal progenitors by inhibition of TGF-β/activin/nodal signaling using SB-431542

“…The hESC lines: Harvard HUES-9 (34) (kindly provided by Dr D Melton) and in-house hESC line KMEB2 (35) were maintained undifferentiated using g-irradiated (266.7 rads/min for 15 minutes) primary mouse embryonic fibroblast feeder cells seeded at 20,000 cells/cm 2 in plates (NUNC, Roskilde, Denmark) precoated with gelatin (0.1%) (G1393, Sigma, St. Louis, MO, USA). Undifferentiated hESCs were cultured with KO-Medium (KO-DMEM, 85%; 10829-018, Invitrogen, Taastrup, Denmark) supplemented with knockout serum replacement (KO-SR, 15%; 10828-028, Invitrogen), Glutamax (1%; 35050-038, Invitrogen), MEM nonessential amino acids (1%; 11140-035, Invitrogen), bmercaptoethanol (0.1 mM; M7522, Sigma-Aldrich, Brondby, Denmark), penicillin/streptomycin [5000 U/mL (5000 mg/mL), 15070, Invitrogen], human serum albumin (0.5%, SSI, 8409), and basic fibroblast growth factor (bFGF, 5 ng/mL; 13256-029, Invitrogen).…”

The Potential for Immunogenicity of Autologous Induced Pluripotent Stem Cell-derived Therapies

“…Thus, the 10 -20% failure rate of teratoma formation reported by Zhao et al (9) and Araki et al (10) may have been due to insufficient vascularization or cell-cell contact rather than rejection per se. This is supported by the fact that all three studies reported T cell infiltration into teratomas after establishment, but only the two that transplanted subcutaneously reported Ͻ100% teratoma formation, as well in previous work (18). Of course, these teratoma experiments do not reflect the path of clinical translation, which will involve transplantation of cell types differentiated in vitro from iPSCs.…”