International Journal of Cell Cloning, Vol 3, 407-414, Copyright © 1985 by AlphaMed Press
Effects and interactions of epidermal growth factor, insulin, hydrocortisone, and estradiol on the cloning of human tumor cells
SE Singletary, B Tomasovic, G Spitzer, SL Tucker, V Hug and B Drewinko
We investigated the effects and interactions of epidermal growth factor
(EGF), insulin, hydrocortisone, and estradiol on the growth of 18 freshly
obtained human tumors in our human tumor stem cell assay (HTSCA) cultured
at a reduced serum concentration (8.5% ml). All possible combinations of
these four supplement factors were added to the assay to determine the
ability of each component to enhance colony formation. We found that
hydrocortisone was the most effective single supplement in stimulating
colony growth in the HTSCA. Supplementation with insulin, estradiol, or
both had some growth-promoting effect but not as great as hydrocortisone.
Moreover, the addition of insulin, estradiol, or both often demonstrated a
negative interaction with hydrocortisone. EGF supplementation alone; in
dual combination with insulin, estradiol, or hydrocortisone; or in
combination with estradiol and insulin in the assay did not significantly
increase colony formation. However, EGF added to the cultures containing
hydrocortisone with insulin and/or estradiol significantly increased colony
formation and reversed the negative effect of insulin and estradiol on
hydrocortisone activity. Thus, under conditions of our assay, the most
effective combination in promoting colony growth contained all four
factors.
