Figure 6

Reversible effects of long-term retinoid treatment of WT culture ws568li. (A) WT cells were continuously cultivated in the presence of 10 μM ATRA for 4 weeks. From time point t₁ on cells were either kept in ATRA containing medium (ATRA) or cultivated in normal medium (D10). At time point t₂ ATRA was given again (D10→ATRA) to one of the cultures. (B) WT cells were continuously cultivated in 10 μM 4HPR for 2 month. At time point t₁ two cultures were switched to normal medium (D10), leading to an increase in proliferation after 5 days. If 4HPR was given again from time point t₂ on cell growth was reduced again.