Fig. 4. The benzimidazole side-chain of SR-4835 modulates its molecular glue activity.

A Chemical structure of CR8 and SR-4835, alongside developed analogues. B A375 cells were treated with SR-4835, CU-0904, CU-0905 or CU-0906 for 2 h at indicated concentrations, and cyclin K levels were quantified by densitometric analysis and normalized to tubulin. EC₅₀ concentration for SR-4835 was 112 nM, 197 nM for CU-0904, 241 nM for CU-0905 and 333 nM for CU-0906. C Immunoblot depicting RPB1 phosphorylation levels in A375 cells treated with SR-4835, CU-0904, CU-0905 or CU-0906 (1 and 10 µM) for 6 h. D qPCR of A375 cells treated for 6 h with SR-4835, CU-0904, CU-0905 or CU-0906 (100 nM). E Immunoblot of A375 cells treated with SR-4835, CU-0904, CU-0905 or CU-0906 (100 and 300 nM) for 24 h. F Proliferation assay was performed using A375 cells treated with increasing doses of SR-4835, CU-0904, CU-0905 or CU-0906 for 72 h. IC₅₀ concentration for A375 treated with SR-4835 was 69 nM, 288 nM for CU-0904, 160 nM for CU-0905 and 240 nM for CU-0906. B Data are represented as mean ± SEM of independent experiments, n = 3. C, E, F Representative data of n = 3. Data are represented as mean ± SD of independent experiment, n = 3 (D) or independent replicate, n = 6 (F). P values signification: ns not significant; *P < 0.05; **P < 0.01; ***P < 0.01; ****P < 0.001.