Figure 3

Δ1–9-G129R-hPrl reduces the MCF-7 cell number in combination with doxorubicin or paclitaxel. (a) Sulphorhodamine B assay of MCF-7 cells treated for 48 hours with chemotherapy or control medium (10% charcoal stripped serum (CON)) alone (empty bars) or in combination with 1,000 ng/ml Δ1–9-G129R-hPrl (Δ1–9) (filled bars). *P < 0.05 by Student t test between paired bars. Forty-eight-hour MCF-7 dose–response curves to (b) doxorubicin, and (c) paclitaxel alone (▲) or in combination with 1,000 ng/ml Δ1–9 (■). (d) MCF-7 cells in monolayer culture treated with 1 μM doxorubicin for pulse durations of 2, 6 and 12 hours before removal of doxorubicin and subsequent culture in control medium in the absence (solid lines) or presence (broken lines) of 1,000 ng/ml Δ1–9. Medium was refreshed every 2 to 3 days thereafter. P < 0.05 by Student t test at 5 days (*) and 10 days (†). (e) MCF-7 cells treated with 1 μM doxorubicin (DOX) for 24 hours were cultured until exponential growth resumed (5 to 6 weeks) and were analysed for prolactin (PRL) mRNA expression. ARPP0, acidic ribosomal phosphoprotein P0.