Effect of embryonic mouse cells BALB/c-3T3 on the proliferation of the human mammary cancer cell line T-47D

Abstract

In the present study, we explore the effect of the cellular extracts and culture medium of the embryonic mouse cell line BALB/c-3T3 (clone A31) on the proliferation and DNA content of the human T-47D breast cancer cell line. These effects were also studied in the presence of the potent anti-estrogen ICI 164,384. All experiments were prepared in MEM medium containing 5% fetal calf serum treated with dextran charcoal, as well as the homogenization of the BALB/c-3T3 cells to obtain the cellular extract. Aliquots of cellular extracts (2%) corresponding to 2 × 10 6 cells, or culture medium (16%), are incubated with the T-47D cells. After 9 days of culture, cellular extracts and culture medium provoke an intense proliferative effect corresponding respectively to 2 and 5 times the control value of T-47D cells. These effects on cell proliferation are correlated with DNA content. Although the anti-estrogen ICI 164,384 (5 × 10 −8 M) alone decreases the proliferation of T-47D cells by half, the presence of the culture medium from the BALB/c-3T3 cells abolishes this effect and, on the contrary, increases the cell proliferation 4-fold. It is concluded that mouse embryonic cells (BALB/c-3T3) contain factor(s) which stimulate very intensively the proliferation of hormone-dependent T-47D mammary cancer cells. This factor(s) is present in both the cell and the culture medium and can antagonize the anti-proliferative effect of the anti-estrogen ICI 164,384.