International Journal of Cell Cloning, Vol 5, 158-169, Copyright © 1987 by AlphaMed Press
Analysis of human ascites effect on clonogenic growth of human tumor cell lines and NRK-49F cells in soft agar
HJ Broxterman, C Sprenkels-Schotte, P Engelen, A Leyva and HM Pinedo
We studied the factors that control the capacity of tumor cells to grow in
soft agar. And, we analyzed the effect of cell-free ascites (CFA) obtained
from ovarian cancer patients in combination with various media on the
cloning efficiency of H-134 and OVCAR-3nu ovarian carcinoma cell lines and
the WiDr colon carcinoma cell line. Seven batches of CFA consistently
enhanced the soft agar growth of tumor cells more efficiently than tested
sera. The addition of charcoal-treated bovine serum albumin (BSA) lowered
the amount of CFA required for optimal tumor cell growth. As little as 1.25
ng of epidermal growth factor (EGF)/ml further improved OVCAR-3nu soft agar
growth in combination with all of the amounts of CFA tested. Thus, neither
BSA nor EGF seems to account for the colony-stimulating effect of ascites
on tumor cells. Four batches of CFA were tested for stimulating soft agar
growth of normal rat kidney (NRK-49F) fibroblasts; all induced colonies of
different morphologies. This effect was potentiated by EGF, which suggests
the presence of several transforming growth factor-like activities in CFA.
The results show that differences in cloning efficiency of tumor cells of
one or two orders of magnitude can be found between standard
(anchorage-dependent growth-supporting) media and media optimalized for
soft agar growth, such as CFA in the presence of EGF. This paper will
discuss the similarity in effects of CFA on various tumor cells and NRK
cells, and possible implications of the stimulatory effects of CFA.
