RGS2 inhibits Flt3-ITD– and IL-3–mediated proliferation of 32D cells. (A) Lac-inducible expression of RGS2. The 32D/Flt3-ITD cells were stably transfected with a Lac-inducible RGS2 construct or a control vector. Cells were cultured in the presence or absence of IPTG (for induction of RGS2). RGS2 expression was measured by real-time RT-PCR. The amplification plot shows the amount of RGS2 cDNA (ΔRn) during each cycle of the PCR reaction. (B) RGS2 inhibits Flt3-ITD– and IL-3–mediated autonomous proliferation of 32D cells. The 32D/Flt3-ITD cells were stably transfected with a Lac-inducible RGS2 construct (right) or a control vector (left). Cells were starved of IL-3 for 12 hours. Subsequently, the indicated cytokine with (▪) or without IPTG (▦) was added. DNA synthesis was detected by 3H-thymidine incorporation. (C) RGS2 inhibits Flt3-ITD–induced clonal growth of 32D cells. The 32D cells stably transfected with Flt3-ITD were transiently cotransfected with RGS2 (with or without IL-3 stimulation) or with an empty vector. One day after transfection, 1 × 105 cells were plated per dish in the presence of G418 as selection marker. Colonies were analyzed on day 8.
