HEAT-SHOCK INDUCES DIFFERENTIATION OF HUMAN EMBRYONAL CARCINOMA-CELLSINTO TROPHECTODERM LINEAGES

NCR-GS cells were established from a testicular embryonal carcinoma an d are highly multipotential, differentiating into trophectoderm cells upon exposure to retinoic acid. Differentiated NCR-G3 cells begin to p roduce human chorionic gonadotropin (hCG), a trophectoderm-specific ho rmone. We have previously isolated the up-regulated genes at the early stage of differentiation. One of them was found to be a heat shock pr otein gene. The heat shock protein gene (HSP90) is induced at the earl y stage of differentiation and decreases to the basal level or under t he basal level at the later stage. We speculate that heat shock per se induces the differentiation of human EC cells. With exposure to heat, NCR-G3 cells began to express a series of differentiation markers suc h as cytokeratin and hCG;, Heat, which is classically known to induce heat shock proteins, is able to differentiate an embryonal cell line i nto trophectoderm lineages, implying a new recognized function of a he at-like event in early differentiation. (C) 1998 Academic Press, Inc.