BI-D1870 is a small molecule, which inhibits RSK1, RSK2, RSK3 and RSK4 in vitro with an IC(50) of 10-30 nM, but does not significantly inhibit ten other AGC kinase members and over 40 other protein kinases tested at 100-fold higher concentrations. BI-D1870 is cell permeant and prevents the RSK-mediated phorbol ester- and EGF (epidermal growth factor)-induced phosphorylation of glycogen synthase kinase-3beta and LKB1 in human embryonic kidney 293 cells and Rat-2 cells. BI-D1870 exhibited a dose-responsive antiproliferative effect on OSCC cells with relative sparing of normal human oral keratinocytes. The compound inhibited the downstream RSK target YB-1 and caused apoptosis. In addition, BI-D1870 also induced G2/M arrest by modulating the expression of p21 and other cell cycle regulators. BI-D1870 may be of useful in oral squamous cell carcinoma therapy. BI-D1870 has being shown to ameliorate experimental autoimmune encephalomyelitis in mice. BI-D1870 administration protected mice from EAE by reducing the infiltration of TH1 and TH17 cells into the CNS and decreasing mRNA levels of Ccr6 in TH17 cells. These results suggest that RSK inhibition is a promising strategy for the treatment of MS.