NK-cell surveillance mechanisms [9, 10] and NK cell stimulation with interleukin (IL)-2 [11] can also contribute to the antitumor effect. NK cells against neuroblastoma cells and could lower the antibody dose required for efficacy, thereby reducing toxicity. The effect of IL-2 may vary among individuals and a biomarker would be useful to predict ADCC following IL-2 activation. Sub-populations of NK cells may have different levels of activity dependent on their licensing status, KIR expression, and HLA-KIR interaction. Better understanding of HLA-KIR interactions and the molecular changes following retinoid-induced differentiation is necessary to delineate their role in ADCC. Keywords: anti-GD2 antibody, IL-2, neuroblastoma, NK cells, missing-self Introduction Decades of research have improved our understanding of the interactions Angiotensin 1/2 (1-5) between the immune system and tumors. Consequently, numerous therapeutic advances for adult cancers have made their way into the clinic in the past 30 years, including interventions to modulate immune systemCmediated ablation of tumor cells with antibodies that target tumor-specific antigens for antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity [1]. Other strategies are geared towards chimeric antigen receptor T cells [2] and immune check-point inhibitors [3] to exploit T Angiotensin 1/2 (1-5) cellCmediated tumor cell ablation. In addition, antibodies that abrogate cell receptor signaling (e.g., human epidermal growth factor receptor 2 [4]) or interfere with the tumor microenvironment (e.g., neutralizing antibodies against vascular endothelial growth factor [5]) are routinely used to provide therapeutic benefit. Although several successful Angiotensin 1/2 (1-5) immunotherapy trials have been conducted for pediatric leukemias and lymphomas, far fewer have been conducted for pediatric solid tumors. To date, the most significant immunotherapy study for pediatric solid tumors investigated the efficacy of anti-disialoganglioside (GD2) antibody for neuroblastoma [6]. GD2 is a suitable target for antibody therapy because it is abundantly expressed in most neuroblastoma cells and its expression is restricted in normal cells, including peripheral nerves [7]. Anti-GD2 antibodies induce ADCC via natural killer (NK) cells [8]. NK-cell surveillance mechanisms [9, 10] and NK cell stimulation with interleukin (IL)-2 [11] can also contribute to the antitumor effect. This has led to clinical trials incorporating IL-2, anti-GD2 antibodies, and adoptive transfer of haploidentical NK cells for the treatment of neuroblastoma (“type”:”clinical-trial”,”attrs”:”text”:”NCT01576692″,”term_id”:”NCT01576692″NCT01576692, “type”:”clinical-trial”,”attrs”:”text”:”NCT02650648″,”term_id”:”NCT02650648″NCT02650648, “type”:”clinical-trial”,”attrs”:”text”:”NCT00877110″,”term_id”:”NCT00877110″NCT00877110, and “type”:”clinical-trial”,”attrs”:”text”:”NCT01857934″,”term_id”:”NCT01857934″NCT01857934). Retinoid-based differentiation therapy has been used for children with neuroblastoma [6, 12]. Because GD2 is a marker of mature neurons, anti-GD2 antibody is currently administered in combination with retinoic acid (ATRA), which is used with anti-GD2 antibody therapy in the Rabbit Polyclonal to SLC16A2 clinic [6]. These studies are the first to use O-PDXs and patient-matched NK cells. Together, our data suggest that IL-2 is an important component of anti-GD2 Angiotensin 1/2 (1-5) antibody therapy in neuroblastoma. Moreover, we found that ADCC contributes more to NK-cell degranulation ex vivo than does NK cell surveillance. By using our ADCC assay with patient-match O-PDXs and NK cells, we demonstrate the feasibility of studying immunotherapy strategies for individual patients with neuroblastoma. Materials and methods Tumor cells Neuroblastoma cell lines were maintained in Roswell Park Memorial Institute 1640 medium (Lonza, Walkersville, MD; CHLA90, NBLS, SK-N-BE2, SK-N-JCI, SK-N-MM), Dulbeccos Modified Eagle Medium (Lonza; NB-1691, SK-N-NAS, SK-N-NFI), Eagles Minimum Essential Medium (EMEM; American Type Culture Collection [ATCC], Manassas, VA; IMR32, SK-N-SH), and EMEM/Kaighns modification of Hams F12 media (ATCC; SH-SY5Y) supplemented with 10% heat-inactivated fetal bovine serum Angiotensin 1/2 (1-5) (Biowest, Kansas City, MO), 100 IU/mL penicillin, 100 g/mL streptomycin, and 2 mM L-glutamine if base medium did not contain L-glutamine (all.
