Growth suppression of transformed cells by a human placental extract not related to transforming growth factor Β

  • J. L. Klein
  • E. Hamel
  • J. L. Tayot
  • H. Yamasaki
Original Papers Experimental Oncology

DOI: 10.1007/BF01625424

Cite this article as:
Klein, J.L., Hamel, E., Tayot, J.L. et al. J Cancer Res Clin Oncol (1991) 117: 192. doi:10.1007/BF01625424


We have examined whether human placental extracts contain tumour-growth-inhibitory factors. One fraction (EAP) from such extracts inhibited growth, in soft agar, ofHa-ras-transformed BALB/c 3T3 cells and human squamous lung carcinoma A-2182 cells. However, this fraction had no effect on the anchorage-dependent growth of these cells, although there was a slight mitogenic activity on nontransformed cells. These data together with those on plating efficiency indicated no significant cytotoxicity of EAP on transformed cell lines. Although this fraction contained transforming growth factorΒ (TGFΒ), this cannot account for its inhibitory activity, since (a) pure TGFΒ does not inhibit anchoragedependent growth of Ha-ras-transformed BALB/c 3T3 cells, (b) EAP retains its inhibitory activity in the presence of antibodies against TGFΒ and (c) the inhibitory activity did not copurify with TGFΒ. Partial characterization of our inhibitory factor suggests that the inhibitory factor is a new tumour-growth-inhibitory factor.

Key words

Suppression of transformed phenotype TGFβ Growth factors Human placenta 



sodium dodecyl sulphate

TGFα orΒ

transforming growth factorα orΒ

TIF1 or 2

transformed inhibitory factor 1 or 2


human squamous lung carcinoma cell line

BALB/c 3T3 1-1

mouse fibroblast cell line, clone A31 1-1

BALB/c 3T3 Ha-ras, BALB/c 3T3 1-1

cells transformed by Ha-ras oncogene


Chinese hamster ovary; MEM, minimum essential medium

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • J. L. Klein
    • 1
  • E. Hamel
    • 1
  • J. L. Tayot
    • 2
  • H. Yamasaki
    • 1
  1. 1.International Agency for Research on CancerLyon Cedex 08
  2. 2.Institut MerieuxMarcy-l'EtoileFrance