Sigma receptor ligand fused to a proteasome-impairing scaffold shows promise against glioblastoma and myeloma cells
- Four hybrid molecules join a sigma receptor modulator (RC-106) to a proteasome-directed fragment (IP24) through PEG spacers, testing different attachment points and linker lengths.
- All kept sigma receptor binding; where the linker was attached on the RC-106 core steered S1R versus S2R preference.
- Hybrids outperformed their parents in glioblastoma and myeloma lines, with the best one active at low-micromolar level and also in 3D spheroids.
- They did not block purified 20S proteasome but impaired proteasome function in intact cells, suggesting an indirect, context-dependent mechanism.
💡 Points Based on the abstract
Where is the unconjugated 1:1 mixture of RC-106 and IP24? Without it, I can't tell whether the hybrids' edge over the parents reflects true bifunctionality or just two lipophilic fragments adding up. Since they spare purified 20S yet impair proteasome function in cells, I'd also want a sigma-dead analogue with the same PEG linker to show receptor engagement actually drives the effect.