Effects of ▵STAT5 expression and coincubation with cytarabine and hydroxyurea on viability of Ba/F3p210 cells.

(A) The effects of ΔSTAT5 expression on viability were tested after cells were incubated with various concentrations of cytarabine (1000-31.6 nmol/L) for 36 hours. When coincubated with doxycycline (1 μg/mL) (▪), Ba/F3p210ΔSTAT5 cells were more susceptible to killing induced by cytarabine than were cells maintained in the absence of doxycycline (•). No significant effect on viability was observed when Ba/F3p210Ctrl cells were coincubated with doxycycline and cytarabine. (B) Ba/F3p210ΔSTAT5 cells were coincubated in either the presence (▪) or absence (•) of doxycycline (1 μg/mL) with various doses of hydroxyurea for 5 hours. After 36 hours, they were analyzed for viability. Coincubation with doxycycline enhanced killing induced by various doses of hydroxyurea. No effect of doxycycline on viability was observed when Ba/F3p210Ctrl cells were coincubated with hydroxyurea.