Discovery of CLKs inhibitors for the treatment of non-small cell lung cancer

Targeted inhibition of the Wnt pathway is a promising strategy for treating NSCLC. CDC2-like kinase 2 (CLK2), a dual-specificity kinase responsible for phosphorylating serine/arginine-rich (SR) proteins, can modulate Wnt signaling through the alternative splicing of Wnt target genes, making CLK2 an attractive therapeutic target for NSCLC. In this study, we report the synthesis, optimization, and evaluation of CLK2 inhibitors that effectively suppress the proliferation of NSCLC cells, with the identification of the lead compound LBM22. Notably, compound LBM22 demonstrated potent inhibition of CLK2 (IC₅₀ = 3.9 nM), leading to broad suppression of NSCLC cells proliferation and induction of apoptosis. Furthermore, LBM22 dose-dependently suppressed SR protein phosphorylation (pSRSF4, pSRSF5, and pSRSF6) in NSCLC cells, while downregulating the expression of Wnt pathway-related proteins (p-β-catenin, Axin 2, and c-Myc) as well as anti-apoptotic proteins (Bcl-2 and Mcl-1). Additionally, significant antiproliferative activity was observed for LBM22 in 3D cultured H1975OR cells. In conclusion, LBM22 emerges as a promising CLK2 inhibitor for the treatment of NSCLC.