IL-15-secreting CAR natural killer cells directed toward the pan-cancer target CD70 eliminate both cancer cells and cancer-associated fibroblasts.

BACKGROUND: It remains challenging to obtain positive outcomes with chimeric antigen receptor (CAR)-engineered cell therapies in solid malignancies, like colorectal cancer (CRC) and pancreatic ductal adenocarcinoma (PDAC). A major obstacle is the lack of targetable surface antigens that are not shared by healthy tissues. CD70 emerges as interesting target, due to its stringent expression pattern in healthy tissue and its apparent role in tumor progression in a considerable amount of malignancies. Moreover, CD70 is also expressed on cancer-associated fibroblasts (CAFs), another roadblock for treatment efficacy in CRC and PDAC. We explored the therapeutic potential of CD70 as target for CAR natural killer (NK) cell therapy in CRC, PDAC, focusing on tumor cells and CAFs, and lymphoma. METHODS: RNA-seq data and immunohistochemical analysis of patient samples were used to explore CD70 expression in CRC and PDAC patients. In addition, CD70-targeting CAR NK cells were developed to assess cytotoxic activity against CD70+ tumor cells and CAFs, and the effect of cytokine stimulation on their efficacy was evaluated. The in vitro functionality of CD70-CAR NK cells was investigated against a panel of tumor and CAF cell lines with varying CD70 expression. Lymphoma-bearing mice were used to validate in vivo potency of CD70-CAR NK cells. Lastly, to consider patient variability, CD70-CAR NK cells were tested on patient-derived organoids containing CAFs. RESULTS: In this study, we identified CD70 as a target for tumor cells and CAFs in CRC and PDAC patients. Functional evaluation of CD70-directed CAR NK cells indicated that IL-15 stimulation is essential to obtain effective elimination of CD70+ tumor cells and CAFs, and to improve tumor burden and survival of mice bearing CD70+ tumors. Mechanistically, IL-15 stimulation resulted in improved potency of CD70-CAR NK cells by upregulating CAR expression and increasing secretion of pro-inflammatory cytokines, in a mainly autocrine or intracellular manner. CONCLUSIONS: We disclose CD70 as an attractive target both in hematological and solid tumors. IL-15 armored CAR NK cells act as potent effectors to eliminate these CD70+ cells. They can target both tumor cells and CAFs in patients with CRC and PDAC, and potentially other desmoplastic solid tumors.

Sizing nanomatter in biological fluids by fluorescence single particle tracking.

Accurate sizing of nanoparticles in biological media is important for drug delivery and biomedical imaging applications since size directly influences the nanoparticle processing and nanotoxicity in vivo. Using fluorescence single particle tracking we have succeeded for the first time in following the aggregation of drug delivery nanoparticles in real time in undiluted whole blood. We demonstrate that, by using a suitable surface functionalization, nanoparticle aggregation in the blood circulation is prevented to a large extent.

Statistical analysis of tablet breakability methods.

PURPOSE: Using a model tablet, the influence of breakability methodology on mass uniformity of half- and quarter-tablets as well as the comparison of different data acquisition and evaluation approaches were investigated. Moreover, different breakability evaluation criteria were compared based upon distribution as well as distribution-free models. METHODS: A cross-scored tablet, i.e. having two break-marks, was broken by different methods by different persons, and the masses determined for the whole (unbroken) tablets, the half-tablets and quarter-tablets. RESULTS: Beside the possible interaction between the methodology and the person breaking the tablets, the major factor significantly influencing the mass uniformity of broken tablets is the breakability methodology. The best results, i.e. smallest loss and smallest variability, are obtained when the breaking force applied by the thumbs is directed towards the score side of the tablet, i.e. by "opening" the score. Using our model tablet, significant differences between the different evaluation criteria are observed, with the USP/NF approach being best in line with the detailed analysis of all broken tablets. CONCLUSIONS: Assuming that for this model tablet the variance is a linear function of the break-line length, the standard deviation of quarter-tablets is theoretically calculated to be 0.87 times the standard deviation of the half-tablets. As the absolute standard deviation, expressed in mass units, will thus remain approximately identical, the relative standard deviation will nearly double as the mean mass of the quarter-tablets will be half of the mean mass of the half-tablets. This was experimentally confirmed.