A-D) Real time RT-PCR measured the effect of 25 nM SDF1 and CK1α siRNA treatment for 1 and 6 hours on cell cycle regulators p21Cip1, p27Kip1, p57Kip1 and Bmi1. E) SDF1 treatment increased cyclin D1 Y286 phosphorylation and decreased total levels. Treatment with 5 μM BIO antagonized the effect of SDF1 on cyclin D1 levels. Values are the mean ± SE, n=2-3, * p<0.05, ** p<0.01 vs Scr siR, †† p<0.01 vs Veh. F) Schematic summary of SDF1 – dependent signaling through CK1α and GSK3β resulting in attenuated Bmi-1 and cyclin D1.