Serum changes the response of cultured Morris hepatoma 7777 cells to autocrine growth factors.
The addition of calf serum to culture medium alters the biological response of Morris hepatoma 7777 (MH) cells to autocrine growth factors isolated from conditioned medium of the investigated cells. Acetic acid (AA) extract obtained from conditioned medium of MH cells showed a change in anchorage-independent growth-regulatory activity from stimulation (serum-free) to inhibition (10% calf serum). Two protein fractions of apparent molecular weight 15 and 7.5 kDa isolated from AA-extract by Bio-Gel P-60 filtration also changed their growth-regulatory activity after supplementation of culture medium with calf serum. The contradictory effect of autocrine regulators estimated in soft agar using the 3H-thymidine (3H-TdR) incorporation test and colony formation assay gave generally comparable results, except in the case of the 15-kDa fraction. The most active 7.5-kDa fraction stimulated 3H-TdR incorporation and colony formation in serum-free medium up to about 300 and 500% respectively, while in the presence of 10% calf serum inhibition of about 20 and 50% has been observed. Our results suggest that the fraction contains an autocrine growth factor(s), whose activity is inverted in the presence of serum.
Guzik
K
K
Department of Animal Biochemistry, Jagiellonian University, Krakow, Poland.
Klein
A
A
D000818:Animals; D002460:Cell Line; D003470:Culture Media; D004273:DNA, Neoplasm / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D006133:Growth Substances / Q000302:isolation & purification / Q000494:pharmacology*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology*; D008970:Molecular Weight; D051381:Rats; D013936:Thymidine / Q000378:metabolism; D014316:Tritium; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014410:Tumor Stem Cell Assay
D003470:Culture Media; D004273:DNA, Neoplasm; D006133:Growth Substances; D014316:Tritium; D013936:Thymidine