title: Enhancement of erythroid progenitor cell growth in medium conditioned by a human cancer cell line, KONT.
abstract: Erythroid-potentiating activity (EPA) was detected in culture medium conditioned by a human cancer cell line (KONT) that produces colony-stimulating activity (CSA), using erythroid colony formation in vitro. EPA in the medium conditioned by the KONT cells (KONT-CM) was markedly heat stable. After treating KONT-CM at 80 degrees C for 30 min, 30% EPA remained, while CSA was completely inactivated. Both EPA and CSA appeared in approximately the same fractions of the gel filtration, indicating a molecular weight of approximately 30,000 daltons. EPA bound partially to Concanavalin-A Sepharose, whereas CSA almost did not bind. Our results indicate that EPA can be separated from CSA based on heat stability and binding to Concanavalin-A Sepharose.
mesh_terms: D002455:Cell Division; D002999:Clone Cells / Q000166:cytology; D003115:Colony-Stimulating Factors / Q000096:biosynthesis* / Q000494:pharmacology; D003470:Culture Media; D004912:Erythrocytes / Q000166:cytology*; D004920:Erythropoiesis / Q000187:drug effects; D004921:Erythropoietin / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006358:Hot Temperature; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*
chemical_list: D003115:Colony-Stimulating Factors; D003470:Culture Media; D004921:Erythropoietin