Fine-Tuning Photochemical Immunogenic Cell Death by a Panel of Verteporfin-Lipid Nanoparticles: A Data-Driven...

Immunogenic cell death (ICD) is an immunostimulatory process that can be induced by light-activated photosensitizers, but its mechanisms remain unclear, especially with lipid nanoparticle (LNP) formulations. In this study, a multivariate, data-driven analysis was conducted using a panel of five verteporfin(V)-LNPs to identify the attributes that lead to the greatest photochemically-induced exposure of ICD markers in pancreatic cancer cells. These attributes include varying production of Type I (radicals) or Type II (singlet oxygen) reactive oxygen species (ROS) upon 690 nm activation, localization in different organelles, variable cellular uptake efficiencies, and different phototoxicity levels. Using principal component analysis, we identified that, unexpectedly, Type I ROS is most strongly associated with ICD marker exposure, which leads to dendritic cell activation ex vivo, while Type II ROS shows the weakest association. Furthermore, V-LNP localization in the endoplasmic reticulum and mitochondria is most strongly associated with exposure of ICD markers, while lysosomal localization shows the weakest association. ICD marker exposure is proportional to the degree of phototoxicity and cellular uptake efficiency for all V-LNPs. These findings provide critical insights into the multiparametric mechanism underlying photochemical ICD induced by V-LNPs and can inform the rational design of photochemical LNP constructs for augmenting anticancer immune responses.