Development of Experimental Tumors Formed by Mouse and Human Embryonic Stem and Teratocarcinoma Cells after Subcutaneous and Intraperitoneal Transplantations into Immunodeficient and Immunocompetent Mice

Abstract

Pluripotent stem cells represent an attractive cell source for regenerative medicine. However, the risk of teratoma formation after transplantation restricts their clinical application. Therefore, to adequately evaluate the potential risk of tumorigenicity after cell transplantation into human tissues, effective animal transplantation assays need to be developed. We performed a multiparameter (cell number, transplantation site, cell type, host) comparative analysis of the efficiency of tumor development after transplantation of mouse and human embryonic stem (ES) cells and their malignant counterparts, teratocarcinoma (EC) cells, into animal recipients and revealed several key correlations. We found that the efficiency of tumor growth was higher after intraperitoneal than after subcutaneous transplantations of all cell lines studied. The minimal cell numbers sufficient for tumor growth in immunodeficient nude mice were 100-fold lower for intraperitoneal than for subcutaneous transplantations of mouse and human ES cells (10 3 vs. 10 5 and 10 4 vs. 10 6 , respectively). Moreover, mouse ES and EC cells formed tumors in immunodeficient and immunocompetent mice more effectively than human ES and EC cells. After intraperitoneal transplantation of 10 3 , 10 4 , and 10 5 mouse ES cells, teratomas developed in 83%, 100%, and 100% of nude mice, whereas after human ES cell transplantation, teratomas developed in 0%, 17%, and 60%, respectively. In addition, malignant mouse and human EC cells initiated tumor growth after intraperitoneal transplantation significantly faster and more effectively than ES cells. Mouse and human ES cells formed different types of teratomas containing derivatives of three germ layers but different numbers of undifferentiated cells. ES cell-like sublines with differentiation potential similar to the parental cell line were recloned only from mouse, but not from human, ES cell teratomas. These findings provide new information about the possibility and efficiency of tumor growth after transplantation of pluripotent stem cells. This information allows one to predict and possibly prevent the possible risks of tumorigenicity that could arise from stem cell therapeutics.

Comparison of Immunomodulation Properties of Porcine Mesenchymal Stromal/Stem Cells Derived from the Bone Marrow, Adipose Tissue, and Dermal Skin Tissue

“…ES cells form teratocarcinomas in transplanted organs in vivo due to their high and inordinate proliferation and differentiation capability, which limits their clinical application [ 44 , 45 ]. Thus, it is critical to determine whether MSCs exhibit this tendency in vivo.…”

Increased activity of TNAP compensates for reduced adenosine production and promotes ectopic calcification in the genetic disease ACDC

“…Trilineage differentiation potential of iPSCs was tested in vitro by monolayer differentiation assays for 5 days and in vivo by teratoma formation assays using established protocols (49). Total RNA was collected, and complementary DNA was produced as previously described (4).…”

Tumorigenic and Differentiation Potentials of Embryonic Stem Cells Depend on TGFβFamily Signaling: Lessons from Teratocarcinoma Cells Stimulated to Differentiate with Retinoic Acid

“…To evaluate tumorigenic potential, differentiating ES R1 and EC F9 cells were transplanted subcutaneously or intraperitoneally into nude mice. According to our previous data on the dynamics of tumor development [ 21 ], the formation of teratomas and teratocarcinomas was monitored in two tissue transplantation sites for 6–30 weeks ( Table 1 ). Within 5-6 weeks, teratomas and teratocarcinomas develop in all nude mice (100%) after the transplantation of ES R1 and EC F9 cells on day 5 of RA stimulation in vitro ( Figure 4 , Table 1 ).…”

“…Therefore, we propose that the ability of pluripotent stem cells to differentiate into primordial germ cells is associated with their ability to develop teratomas containing all types of embryonic cell derivatives. The residual undifferentiated ES cells cannot be considered to be cancerous because unlike EC cells, these cells are capable of differentiation into precursors of three germ layers in teratomas and even in secondary teratomas after recloning and secondary transplantation [ 21 ]. Presumably, the residual undifferentiated ES cells represent an intermediate cell type between pluripotent and primordial germ cells which are both able to develop teratomas.…”

“…However, complete implementation of pluripotent potential is only possible when pluripotent stem cells are reintegrated with the blastocyst [ 6 , 10 – 13 ]. In contrast, in vitro differentiation of the pluripotent stem cells is asynchronous and incomplete; and therefore, the residual undifferentiated cells can initiate teratoma development after transplantation into the tissues of an adult animal recipient [ 14 – 21 ]. This feature of pluripotent stem cells is one of the main issues for the development of safe pluripotent stem cell-based therapy.…”