Alkaline Phosphatase Activity in Mouse Teratoma

TLDR

In mouse teratoma tumors and embryoid bodies, alkaline phosphatase activity correlates with the presence of embryonal carcinoma stem cells. The study classified fifteen teratoma-derived tissue culture lines into pluripotential embryonal carcinoma, nullipotential embryonal carcinoma, and nonmalignant somatic cell groups based on morphology, tumorigenicity, and differentiation capacity. High alkaline phosphatase activity is restricted to embryonal carcinoma cells, with both pluripotential and nullipotential types exhibiting 5‑ to 100‑fold higher levels than somatic lines, and the enzyme’s kinetics resemble those of kidney and placenta phosphatases while differing from liver and intestine forms, underscoring its utility for studying cell differentiation in teratoma.

Abstract

In tumors and embryoid bodies of mouse teratoma a correlation has been established between specific activity of alkaline phosphatase (EC 3.1.3.1) and content of embryonal carcinoma, the stem cell of the tumor. A histochemical study of embryoid bodies has shown that high levels of the enzyme are confined to embryonal carcinoma. Fifteen tissue culture lines could be classified into three groups: (a) lines identifiable as pluripotential embryonal carcinoma by their morphology, tumorigenicity, and capacity to differentiate in vivo; (b) nullipotential embryonal carcinoma, resembling pluripotential embryonal carcinoma in morphology and malignancy but giving rise to undifferentiated tumors; and (c) lines of apparently nonmalignant somatic cells. Both types of embryonal carcinoma possess levels of alkaline phosphatase 5- to a 100-fold higher than the somatic cell lines. The embryonal carcinoma enzyme resembles the enzymes from kidney and placenta in kinetics of thermal inactivation and sensitivity to the inhibitor L-phenylalanine, but is distinguishable from the alkaline phosphatases of liver and intestine. These findings are discussed in relation to the use of teratoma for the study of cell differentiation.