CLK2 inhibitor Indazole1 is a novel potent, selective inhibitor of CLK2 with IC50 of 2.7 nM, 60-fold selectivity over PKA and >600-fold selectivity over a panel of 34 kinases.

ML167 is a highly selective Cdc2-like kinase 4 (Clk4) inhibitor with IC50 of 136 nM, >10-fold selectivity for closely related kinases Clk1-3 and Dyrk1A/1B.

CaNDY is a highly potent rectifier of the aberrant splicing, potently inhibits DYRK1A, DYRK1B, CLK1/CLK2/ with IC50 of 21.6/68.3/116 nM in in vitro kinase assays.CaNDY is a potent and selective inhibitor of DYRK family kinases, CaNDY induces selective degradation of DYRK1A, and inhibits catalytic activity of recombinant DYRK1A with IC50 value of 7.9 nM by competing with ATP, antagonizes the CDC37 interaction with DYRK1A.CaNDY demonstrated CFTR pseudo exon suppression with EC50 of 1.2 uM, 20.4 times lower than that of TG003.Splice modulation by CaNDY is mediated by its CLK-inhibition activity.CaNDY, but not CFTR modulator VX-809, rescues mature CFTR expression from the CFTR gene with the 3,849 + 10 kb C>T mutation, suppresses SRSF phosphorylation.CaNDY (3 uM) treatment rescued CFTR channel activity from CFTRC>T-GFP at an extent comparable to that of CFTRWT-GFP, demonstrating a restoration of functional CFTR expression.

CLK4 inhibitor 96 is a novel potent CLK4 inhibitor with IC50 of 57.5 nM.

GPS167 is a specific small molecule splicing regulator SRSF10 inhibitor, modulates BCLAF1 splicing with IC50 of 2 uM in human colorectal HCT116 cells, directly inhibits CLK1, CLK2 and CLK4, but not SRPK1 and DYRK1A.GPS167 promotes the dephoshorylation of SRSF10 and changes its interaction with partner proteins.GPS167 treatment leads to a partial dephosphorylation of SRSF10 and increases the recovery of CLK1 and CLK4.GPS167 impairs the growth of cancer cell line, elicits p53-dependent cytotoxicity.GPS167 is cytotoxic for human colorectal cancer organoids but not normal organoids.