Evaluation of natural killer cell tumor homing and effector function in response to CDK4/6 and AURKA inhibition in a melanoma tumor-on-a-chip platform

Natural killer (NK) cells have emerged as an important clinical tool cellular immunotherapy. Whereas immune checkpoint blockade (ICB) or chimeric antigen receptor (CAR) T-cell therapy (CAR-T) therapy have been adopted as a first line treatments in different malignancies, such as melanoma, these approaches do not work for all patients. T cells require proper antigen presentation on tumor cells for recognition and to carry out their corresponding cytotoxic functions. Deficiency of tumor antigens, or high variability in those present, make T cell-based CAR-T and ICB ineffective. By contrast, NK cells are not limited by antigen presentation deficiencies, offering a potential alternative approach, yet their efficacy can suffer from immunosuppressive signals. Herein, we sought to develop in vitro and on-chip platforms to identify strategies for enhance, rather than suppress, NK cell homing to tumor cells. We explored the use of inhibition of kinases such as CK4/6 and AURKA to induce tumor cell production of chemokines that NK cells migrate towards in aggressive melanoma models. We evaluated chemokine-aided NK cell migration-homing capabilities and their therapeutic efficacy and found that treatment of both melanoma cell line and patient-tumor constructs (PTCs) with CDK4/6 and AURKA generally resulted in improved NK cell homing to tumor cells and accompanying tumor cell killing. Interestingly, this chemokine-guided NK cell migration did not generate as effective outcomes in models using a mildly aggressive melanoma cell line. For our studies, we used 3D tumor constructs in both static Transwell models and then in a bioengineered NK cell-functionalized tumor-on-a-chip (NK-TOC) platform.