CD73 expression on (A) A549 and (B) GBM10 cells after treatment with TGF-1 for 24 h. deaminase inhibitor (ADAi) EHNA (30 M), respectively. Physique S9. CD73 expression on (A) A549 and (B) GBM10 cells after treatment with TGF-1 for 24 h. Physique S10. (A) CD73 expression on K562 cells. (B) Lytic activity of NK-92 and piggyBac-NKG2D.CAR-NK-92 cells against CD73- K562 cells. (DOCX 914 kb) 40425_2018_441_MOESM1_ESM.docx (915K) GUID:?965E9CCD-D599-4208-A354-CE0AB4DAB4E2 Data Availability StatementThe data presented in this study is usually available upon affordable request to the corresponding authors. Abstract Background The anti-tumor immunity of natural killer (NK) cells can be paralyzed by the CD73-induced generation of immunosuppressive adenosine from precursor ATP within the hypoxic microenvironment of solid tumors. In an effort to redirect purinergic immunosuppression of NK cell anti-tumor function, we showed, for the first time, that immunometabolic combination treatment with NKG2D-engineered CAR-NK cells alongside blockade of CD73 ectonucleotidase activity can result in significant anti-tumor responses in L-Mimosine vivo. Methods NK cells were designed non-virally with NKG2D. CAR-presenting vectors based on the piggyBac transposon system with DAP10 and CD3 co-signaling domains. The anti-tumor immunity of NKG2D.CAR.NK cells in combination with CD73 targeting was evaluated against multiple solid tumor targets in vitro and humanized mouse xenografts in immunodeficient tumor-bearing mice in vivo. Intratumoral migration was evaluated via immunohistochemical staining, while degranulation capacity and IFN- production of NK cells were measured in response to solid tumor targets. Results Our results showed that CD73 blockade can mediate effective purinergic reprogramming and L-Mimosine enhance anti-tumor cytotoxicity both in vitro and in vivo by enhancing the killing ability of CAR-engineered NK cells against CD73+ solid L-Mimosine tumor targets via mechanisms that might imply alleviation from adenosinergic immunometabolic suppression. CD73 blockade improved the intratumoral homing of CD56+ CAR-NK cells in vivo. These designed NK cells showed synergistic therapeutic efficacy in combination with CD73 targeting against CD73+ human lung malignancy xenograft models. Interestingly, CD73 blockade could inhibit tumor growth in vivo independently of adaptive immune cells, innate immunity L-Mimosine or NK cell-mediated ADCC. Conclusions Immunotherapies targeting the adenosinergic signaling cascade, which take action by neutralizing CD73 ectoenzymatic activity, experienced thus far not been evaluated in humanized tumor models, nor experienced the implication of innate immunity been investigated. Taken together, our pre-clinical efficacy data demonstrate, for the first time, the potential of targeting CD73 to modulate purinergic signaling and enhance adoptive NK cell immunotherapy via mechanisms that could implicate autocrine tumor control as well as by mediating adenosinergic signaling. Electronic supplementary material The online version of this article (10.1186/s40425-018-0441-8) contains supplementary material, which is available to authorized users. < 0.05; IFN-+ (%):*< 0.05). In addition, exocytosis of lytic granules made up of granzymes and perforin is usually a prerequisite for the killing ability of NK cells, with CD107a molecules appearing temporarily on the surface. Their expression can be detected as a read-out system for NK cell degranulation . As shown in Fig. ?Fig.4b4b and Additional file 1: Physique S6B (**< 0.01; *< 0.05), NKG2D.CAR-NK-92 cells displayed significantly enhanced surface CD107a expression in response to the target A549 cells). Open in a separate windows Fig. 4 Cytotoxicity and lytic ability of piggyBac-NK2GD.CAR-NK cells against CD73+ targets. a Mean fluorescence intensity (MFI) of intracellular IFN- production by both NK-92 and piggyBac-NKG2D.CAR-NK-92 cells. b Degranulation as measured via CD107a expression (MFI) by both NK-92 and piggyBac-NKG2D.CAR-NK-92 cells. c Lytic activity of NK-92 Rabbit Polyclonal to ACTR3 and piggyBac-NKG2D.CAR-NK-92 cells against CD73+ GBM43, GBM10, A549 or PC3 cells, respectively. Data are offered as the mean??SEM (< 0.05, **<.