CLL cells constitutively express phosphoserine-Stat3 and Ror1 protein, and IL-6 upregulates phosphotyrosine-Stat3 and Ror1 protein levels in MM1 cells.

A. Western immunoblotting of unstimulated CLL cells from 7 different patients shows constitutive expression of phosphoserine-Stat3 and both the 105- and 130-Kd variants of the Ror1 protein. B. MM1 cells were incubated for 2 hours with increasing concentrations of IL-6. As determined by western immunoblotting, IL-6 induced Stat3 tyrosine phosphorylation and upregulated Ror1 protein levels in a dose-dependent manner. C. MM1 cells were incubated with 20 ng/ml IL-6 and harvested at different time points for further analysis. As determined by western immunoblotting, IL-6 induced Stat3 tyrosine phosphorylation and upregulated Ror1 protein levels in a time-dependent manner.