Enhanced CCR2 expression by ACKR2-deficient NK cells enhances increases tumoricidal cell therapy efficacy

Chemokines regulate leukocyte navigation to inflamed sites and specific tissue locales and may therefore be useful for ensuring accurate homing of cell therapeutic products. We, and others, have shown that atypical chemokine receptor 2 (ACKR2)-deficient mice (ACKR2−/−) are protected from metastasis development in cell line and spontaneous mouse models. We have shown that this relates to enhanced CCR2 expression on ACKR2−/− natural killer cells, allowing them to home more effectively to CCR2 ligand-expressing metastatic deposits. Here we demonstrate that the metastatic-suppression phenotype in ACKR2−/− mice is not a direct effect of the absence of ACKR2. Instead, enhanced natural killer cell CCR2 expression is caused by passenger mutations that originate from the creation of the ACKR2−/− mouse strain in 129 embryonic stem cells. We further demonstrate that simple selection of CCR2+ natural killer cells enriches for a population of cells with enhanced antimetastatic capabilities. Given the widespread expression of CCR2 ligands by tumors, our study highlights CCR2 as a potentially important contributor to natural killer cell tumoricidal cell therapy

Natural Antioxidant-Loaded Nanoemulsions for Sun Protection Enhancement

The aim of this study was to formulate nanodispersions to encapsulate antioxidants extracted from olive mill wastewater (OMW) and phycocyanin extracted from Spirulina maxima to act as enhancers for the skin’s protection against UV radiation. For this purpose, two water-in-oil nanoemulsions were prepared using a low-energy homogenization method. Both systems were based on isopropyl myristate as the continuous phase, while water or a mixture of glycerol and water was used as the dispersed phase. Then, antioxidants extracted from OMW and phycocyanin from Spirulina maxima were encapsulated in the water core of the nanoemulsions. The empty and antioxidant-loaded systems were then structurally studied using dynamic light scattering for the detection of their droplet size and stability over time. Electron paramagnetic resonance (EPR) spectroscopy using adequate probes was applied for the characterization of the surfactants’ monolayer in the presence and absence of antioxidants. It was found that the mean droplet diameter of the emulsions was 200 nm. The nanoemulsions remained stable for over 2 months. The encapsulated antioxidants were assessed for their scavenging activity of a model stable radical by applying EPR spectroscopy. It was found that the loaded systems exhibited an increased antioxidant capacity compared with the empty ones. Finally, the most stable system was added to commercial sunscreen lotions and the overall sun protection factor (SPF) was assessed. The sunscreen lotions that contained the nanoemulsions loaded with OMW extracts or phycocyanin showed an increase in their SPF value