title: Production of insulin-like growth factor-II (MSA) by endoderm-like cells derived from embryonal carcinoma cells: possible mediator of embryonic cell growth.
abstract: The present study was carried out to determine if an insulin-like growth factor (IGF) type activity might be produced by embryonal carcinoma-derived cells. The cell line used to condition growth medium for the isolation of secreted growth factors was a newly established Dif 5 cell type. Dif 5 cells are a differentiated endoderm-like cell type derived from F9 embryonal carcinoma cells (which possess properties similar to mouse embryonic stem cells) following extensive exposure to retinoic acid. When growth medium conditioned by Dif 5 cells is chromatographed on Sephadex G-75 in 1 M acetic acid two peaks of activity are observed which compete for specific [125I]iodo multiplication stimulating activity (MSA) binding to PYS cells. MSA is the rat homologue of human IGF-II. The high molecular weight fraction (Mr approximately 60K) apparently corresponds to IGF-binding protein as determined by its ability to bind [125I]iodo-MSA. The low molecular weight fraction (Mr approximately 8K) is biologically active as this fraction stimulates [3H]thymidine incorporation into serum-starved chick embryo fibroblasts. Radioimmunoassay data indicate that the IGF-like activity produced by Dif 5 cells is more closely related to IGF-II than to IGF-I. Undifferentiated embryonal carcinoma stem cell lines (F9, Nulli, and PCC4) produced little of this MSA-like activity, while PYS-2 (parietal endoderm-like) cells produced about 16 ng MSA/10(6) cells/24 hr as determined by radioimmunoassay. Dif 5 and PSA-5E (visceral endoderm-like) cells, are found to secrete significant amounts of MSA into the growth medium (30-50 ng MSA/10(6) cells/24 hr). These findings offer further support to a proposal that MSA (IGF-II) produced by endoderm cells, particularly visceral endoderm, may serve as an early embryonic growth factor.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D002642:Chick Embryo; D002850:Chromatography, Gel; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D054278:Embryonal Carcinoma Stem Cells; D005314:Embryonic and Fetal Development / Q000187:drug effects; D004707:Endoderm / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis*; D008970:Molecular Weight; D014411:Neoplastic Stem Cells / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D013002:Somatomedins / Q000096:biosynthesis*; D013724:Teratoma / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism
chemical_list: D003470:Culture Media; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II; D013936:Thymidine