Introduction:Macrophages are key regulators of immune responses and exhibit remarkable plasticity, ranging from the pro-inflammatory M1 to the anti-inflammatory M2 phenotype.In the tumor microenvironment, macrophages are frequently polarized toward an M2-like profile, contributing to immune suppression and tumor progression.Thus, strategies capable of reprogramming macrophages toward an M1 phenotype represent promising approaches in cancer immunotherapy.Objectives: To evaluate the immunomodulatory effects of phosphatidylserine (PS) and phosphatidylserine/7-ketocholesterol (PS/7-KC) nanoparticles on macrophage polarization and viability.Methodology: Nanoparticles presented diameters between 100-200 nm and negative zeta potential.Murine J774 macrophages were cultured in RPMI 1640 supplemented with fetal bovine serum at 37C and 5% CO 2 .Cells were treated with PS/7-KC nanoparticles (125, 232, and 468 M) for gene expression analysis by RT-PCR.Cytotoxicity and viability were assessed by MTT assay in quadruplicate using PS and PS/7-KC concentrations ranging from 4.6875 to 300 g/100 L at 24 and 72 hours.Statistical analysis was performed using GraphPad Prism 9 with 95% confidence.Results: PS/7-KC nanoparticles induced significant, dose-dependent modulation of macrophage gene expression.The highest concentration (468 M) markedly increased iNOS (log 2 FC +3.4) and IL-12a (log 2 FC +1.66), consistent with M1 polarization.Intermediate and low concentrations strongly repressed MCR and IL-10 expression, with 232 M also promoting moderate IL-12a upregulation.Multivariate analysis revealed significant differences among treatments (p < 0.0001), with iNOS and MCR as the main discriminating markers.MTT assays demonstrated that 72-hour incubation significantly increased cell viability in both PS and PS/7-KC groups, with the highest viability observed in the 72-hour PS/7-KC condition.Conclusion: PS/7-KC nanoparticles effectively promote dose-dependent macrophage reprogramming toward a pro-inflammatory phenotype while enhancing cell viability.These findings support their potential application as an immunotherapeutic strategy for tumor-associated macrophage re-education in cancer.
Favero et al. (Thu,) studied this question.