IN-VITRO INDUCTION OF DIFFERENTIATION BY GINSENOSIDES IN F9 TERATOCARCINOMA CELLS

The aim of this study was to determine the ability of the ginsenosides , extracts of Panax ginseng C.A. Meyer, to cause differentiation of F9 teratocarcinoma stent cells as a model system. F9 stem cells cultured in the presence of the ginsenosides together with dibutyryl cyclic AM P (dbcAMP) became parietal endoderm-like cells. Moreover, the expressi on of differentiation marker genes, such as laminin B1 and type IV col lagen, was increased after treatment with the ginsenosides. Among the various purified ginsenosides, Rh, and Rh, were the most effective at causing differentiation of F9 cells. Since ginsenosides and glucocorti coid hormone have similar chemical structures, we examined the possibi lity of the involvement of a glucocorticoid receptor (GR) in the diffe rentiation process induced by the ginsenosides. According to Southwest ern blot analysis, a 94 kDa protein regarded as a GR was detected in F 9 cells cultured in the medium containing the ginsenosides Rh-1 or Rh- 2. In addition, F9 stem cells treated with the ginsenosides Rh-1 or Rh -2 and with RU486, a glucocorticoid antagonist with a high affinity fo r the GR, did not differentiate into endoderm cells morphologically, a nd the expression of laminin B1 gene was not induced in these cells. I n a gel mobility shift assay, protein factors capable of binding to th e glucocorticoid responsive element (GRE) specifically were detected i n nuclear extracts of the ginsenoside-treated F9 cells. Moreover, over expression of GR by cotransfection of GR expression vector and GRE-luc iferase vector enhanced the transactivation activity of GRE promoter i n the presence of ginsenosides Rh-1 or Rh-2 and was further augmented by dbcAMP. In addition, ginsenosides Rh-1 and Rh-2 bound to a GR asses sed by whole-cell binding assay, even though the specific binding affi nity was weaker compared to dexamethasone. Based on these data, we sug gest that the ginsenosides Rh1 and Rh-2 cause the differentiation of F 9 cells and the effects of ginsenosides might be exerted via binding w ith a GR or its analogous nuclear receptor. Copyright (C) 1996 Elsevie r Science Ltd