Adenosinergic Signaling Alters Natural Killer Cell Functional Responses

Adenosine is a potent immunosuppressive purine metabolite contributing to the pathogenesis of solid tumors. Extracellular adenosine signals on tumor-infiltrating NK cells to inhibit their proliferation, maturation, and cytotoxic function. Cytokine priming imparts upon NK cells distinct activation statuses, which modulate NK anti-tumor immunity and responses to purinergic metabolism. Here, for the first time, we investigated human NK cell responses to adenosinergic signaling in the context of distinct cytokine priming programs. NK cells were shown to be hyper-responsive to adenosine when primed with IL-12 and IL-15 compared to IL-2, exhibiting enhanced IFN-γ expression from CD56bright and CD56dim subsets while modulating the expression of activation marker NKG2D. These responses resulted in signaling that was dependent on mTOR. Adenosine induced upregulation of transcriptional signatures for genes involved in immune responses while downregulating cellular metabolism and other protein synthesis functions that correlate to inhibited oxidative phosphorylation and glycolysis. Overall, our findings show that adenosine acts on specific cellular pathways rather than inducing a broad inhibition of NK cell functions. These responses are dependent on cytokine priming signatures and are important in designing therapeutic interventions that can reprogram NK cell immunometabolism for improved immunotherapies of solid tumors

Tumor-responsive, multifunctional CAR-NK cells cooperate with impaired autophagy to infiltrate and target glioblastoma

Tumor antigen heterogeneity, a severely immunosuppressive tumor microenvironment (TME) and lymphopenia resulting in inadequate immune intratumoral trafficking have rendered glioblastoma (GBM) highly resistant to therapy. As a result, GBM immunotherapies have failed to demonstrate sustained clinical improvements in patient overall survival (OS). To overcome these obstacles, here we describe a novel, sophisticated combinatorial platform for GBM: the first multifunctional immunotherapy based on genetically-engineered, human NK cells bearing multiple anti-tumor functions, including local tumor responsiveness, that addresses key drivers of GBM resistance to therapy: antigen escape, poor immune cell homing, and immunometabolic reprogramming of immune responses. We engineered dual-specific CAR-NK cells to bear a third functional moiety that is activated in the GBM TME and addresses immunometabolic suppression of NK cell function: a tumor-specific, locally-released antibody fragment which can inhibit the activity of CD73 independently of CAR signaling and decrease the local concentration of adenosine. The multifunctional human NK cells targeted patient-derived GBM xenografts, demonstrated local tumor site specific activity in the tissue and potently suppressed adenosine production. We also unveil a complex reorganization of the immunological profile of GBM induced by inhibiting autophagy. Pharmacologic impairment of the autophagic process not only sensitized GBM to antigenic targeting by NK cells, but promoted a chemotactic profile favorable to NK infiltration. Taken together, our study demonstrates a promising new NK cell-based combinatorial strategy that can target multiple clinically-recognized mechanisms of GBM progression simultaneously