title: The growth of malignant and nonmalignant human cells is modulated by a human placental extract.
abstract: BACKGROUND
  In the present paper, malignant and nonmalignant human cells were compared in their response to a fraction (fraction D, FD) of a human placental extract.
  
  
  METHODS
  The activity of FD was tested on cell proliferation both in the absence and in the presence of 5%, 10% and 15% fetal bovine serum (FBS). For cells growing in monolayers, the medium was renewed with fresh medium containing FD 24 hours after plating and 3 days after the first exposure. In breast cancer cells only, it was also changed after 6 days. For leukemic cells, which grow in suspension, FD was added directly to the medium the day of the seeding and then after 3 and 6 days.
  
  
  RESULTS
  In normal fibroblasts, when plated at a low density, a strong inhibitory effect on cell growth was seen with the highest FD dose. This effect was observed in the presence of 5% and 10% FBS, while it disappeared with 15% FBS. In endothelial cells, FD, in the presence of 5% or 10% FBS, produced a modest but constant inhibition of cell proliferation, which was evident after a short treatment and with almost every dose of FD. Breast cancer and leukemic cell lines, plated at a standard density, were markedly inhibited by FD, but this effect was reversed in serum-free conditions, at least in mammary cells. In leukemic cells, after an initial stimulatory effect, FD was not able to counterbalance the absence of serum.
  
  
  CONCLUSIONS
  Our data seem to suggest that in FD both stimulating and inhibitory growth-factors coexist, the activity of which are greatly influenced by the culture conditions used.
authors.affiliation: Institute of Histology and Embryology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Angelucci
authors.forename: G
authors.initials: G
authors.lastname: Lama
authors.forename: G
authors.initials: G
authors.lastname: Sica
mesh_terms: D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D003470:Culture Media; D006801:Humans; D010920:Placenta / Q000502:physiology*; D014020:Tissue Extracts / Q000494:pharmacology
chemical_list: D003470:Culture Media; D014020:Tissue Extracts