Nanoscale engagement of immune checkpoint inhibitor PD-L1 in membrane lipid rafts
Programmed death ligand 1 (PD-L1) plays a key role in several human tumors, and it has recently become a crucial target for cancer therapy. Yet, its subtle regulatory roles beside the well characterized immunosuppression in PD-1/PD-L1 immune checkpoint are still obscure and should be strictly related to its molecular properties in different cell settings. In this study we targeted the plasma membrane organization of PD-L1 in a Non-Small Cell Lung Cancer (NSCLC) cell line by a multiscale fluorescence imaging toolbox that included super-resolution microscopy approaches to reach the nanoscale. Our findings revealed for the first time that PD-L1 is prevalently engaged in the cholesterol-enriched "raft" regions of the cell membrane. Clusterization and engagement in membrane rafts may afford novel targets for the immuno-oncology strategies in the framework of NSCLC and, possibly, other tumor types.