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IMMUNOTHERAPY OF SOLID TUMORS WITH IMMUNOMETABOLICALLY-RETARGETED NATURAL KILLER CELLS
thesisposted on 06.04.2021, 13:45 by Andrea M ChambersAndrea M Chambers
Cancer is responsible for the second highest cause of death in the United States, and lung cancer accounts for 13% of new cancer diagnoses, with the highest rate of cancer death at 24%. Almost 85% of these cases represent non-small cell lung cancer (NSCLC), which includes lung adenocarcinoma, the most common NSCLC subtype. Traditional cancer treatments often only temporarily stop the spread of the disease, but immunotherapies, which are becoming a standard of care, are much more promising. Natural killer (NK) cells are powerful effectors of innate immunity, and genetically engineered NK cells as immunotherapies have had encouraging clinical responses in the treatment of various cancers. However, more progress is needed for solid tumor treatment, especially for lung adenocarcinoma. The activation of cancer-associated ectoenzymes, CD39 and CD73 catalyze the phosphorylation of ATP to AMP to produce extracellular adenosine (ADO), which is a highly immunosuppressive mechanism contributing to the pathogenesis of solid tumors. Understanding adenosine effects on NK cells will help develop more robust immunotherapeutic treatments to improve cytotoxicity against solid tumors. Here, we established that tumor microenvironment ADO results in impaired metabolic and anti-tumor functions of cytokine-primed NK cells. Specifically, peripheral blood-derived NK cells stimulated with IL-2, IL-15, or a combination of IL-12 and IL-15 showed suppressed anti-tumor immunity due to ADO. This was observed by the downregulation of activation receptor expression, cytotoxicity inhibition, impairment of metabolic activity, and alterations in gene expression. To target ADO-producing CD73 on cancer cells, we redirected NK cells by fusing CD73 ScFv with intracellular and transmembrane regions of NK cell specific signaling components derived from FCyRIIIa (CD16). Engineered NK cells were shown to be cytotoxic against lung adenocarcinoma in vitro and impede tumor growth in a lung adenocarcinoma mouse model in vivo. Engineered cells also had higher levels of degranulation and cytokine release, as well as more infiltration into tumors and longer survival time in mice. In summary, the microenvironment of solid tumors is highly immunosupressive, and redirecting NK cell function using a NK-specific anti-CD73 targeting construct will help to promote anti-tumor immunity and
inhibit cancer growth for a potentially powerful new immunotherapy against solid tumors.