Activated Natural Killer Cells in Combination with Anti-GD2 Antibody Dinutuximab Improve Survival of Mice after Surgical Resection of Primary Neuroblastoma.

PURPOSE: Immunotherapy of neuroblastoma that remains after myeloablative chemotherapy with anti-GD2 antibody dinutuximab has increased the two-year event-free and overall survival of high-risk neuroblastoma patients; however, 40% of patients develop recurrent disease during or after this treatment. To determine the potential of such antibody-based immunotherapy earlier in treatment, a mouse model was developed in which surgical resection of the primary tumor was followed by therapy of residual disease with dinutuximab combined with ex vivo-activated human natural killer (aNK) cells. EXPERIMENTAL DESIGN: The effect of combining dinutuximab with human aNK cells was determined in vitro with cellular cytotoxicity and Matrigel invasion assays. The in vivo efficacy of dinutuximab and aNK cells against neuroblastoma was assessed following resection of primary tumors formed by two cell lines or a patient-derived xenograft (PDX) in immunodeficient NOD-scid gamma mice. RESULTS: In vitro, the combination of aNK cells and dinutuximab caused cytotoxicity and decreased invasiveness of three human neuroblastoma cell lines. Treatment of mice with dinutuximab combined with aNK cells after surgical resection of primary intrarenal tumors formed by two cell lines or a PDX decreased tumor cells in liver and bone marrow as evaluated by histopathology and bioluminescence imaging. Survival of mice after resection of these tumors was most significantly increased by treatment with dinutuximab combined with aNK cells compared with that of untreated mice. CONCLUSIONS: The combination of dinutuximab and adoptively transferred human aNK cells following surgical resection of primary neuroblastomas significantly improves survival of immunodeficient mice.

Colony stimulating factor 1 receptor blockade improves the efficacy of chemotherapy against human neuroblastoma in the absence of T lymphocytes.

Tumor-associated macrophages can promote growth of cancers. In neuroblastoma, tumor-associated macrophages have greater frequency in metastatic versus loco-regional tumors, and higher expression of genes associated with macrophages helps to predict poor prognosis in the 60% of high-risk patients who have MYCN-non-amplified disease. The contribution of cytotoxic T-lymphocytes to anti-neuroblastoma immune responses may be limited by low MHC class I expression and low exonic mutation frequency. Therefore, we modelled human neuroblastoma in T-cell deficient mice to examine whether depletion of monocytes/macrophages from the neuroblastoma microenvironment by blockade of CSF-1R can improve the response to chemotherapy. In vitro, CSF-1 was released by neuroblastoma cells, and topotecan increased this release. In vivo, neuroblastomas formed by subcutaneous co-injection of human neuroblastoma cells and human monocytes into immunodeficient NOD/SCID mice had fewer human CD14+ and CD163+ cells and mouse F4/80+ cells after CSF-1R blockade. In subcutaneous or intra-renal models in immunodeficient NSG or NOD/SCID mice, CSF-1R blockade alone did not affect tumor growth or mouse survival. However, when combined with cyclophosphamide plus topotecan, the CSF-1R inhibitor BLZ945, either without or with anti-human and anti-mouse CSF-1 mAbs, inhibited neuroblastoma growth and synergistically improved mouse survival. These findings indicate that depletion of tumor-associated macrophages from neuroblastomas can be associated with increased chemotherapeutic efficacy without requiring a contribution from T-lymphocytes, suggesting the possibility that combination of CSF-1R blockade with chemotherapy might be effective in patients who have limited anti-tumor T-cell responses.

TGFßR1 Blockade with Galunisertib (LY2157299) Enhances Anti-Neuroblastoma Activity of the Anti-GD2 Antibody Dinutuximab (ch14.18) with Natural Killer Cells.

PURPOSE: Immunotherapy of high-risk neuroblastoma using the anti-GD2 antibody dinutuximab induces antibody-dependent cell-mediated cytotoxicity (ADCC). Galunisertib, an inhibitor of TGFßR1, was examined for its ability to enhance the efficacy of dinutuximab in combination with human ex vivo activated NK (aNK) cells against neuroblastoma. EXPERIMENTAL DESIGN: TGFB1 and TGFBR1 mRNA expression was determined for 249 primary neuroblastoma tumors by microarray analysis. The ability of galunisertib to inhibit SMAD activity induced by neuroblastoma patient blood and bone marrow plasmas in neuroblastoma cells was tested. The impact of galunisertib on TGFß1-induced inhibition of aNK cytotoxicity and ADCC in vitro and on anti-neuroblastoma activity in NOD-scid gamma (NSG) mice was determined. RESULTS: Neuroblastomas express TGFB1 and TGFBR1 mRNA. Galunisertib suppressed SMAD activation in neuroblastoma cells induced by exogenous TGFß1 or by patient blood and bone marrow plasma, and suppressed SMAD2 phosphorylation in human neuroblastoma cells growing in NSG mice. In NK cells treated in vitro with exogenous TGFß1, galunisertib suppressed SMAD2 phosphorylation and restored the expression of DNAM-1, NKp30, and NKG2D cytotoxicity receptors and the TRAIL death ligand, the release of perforin and granzyme A, and the direct cytotoxicity and ADCC of aNK cells against neuroblastoma cells. Addition of galunisertib to adoptive cell therapy with aNK cells plus dinutuximab reduced tumor growth and increased survival of mice injected with two neuroblastoma cell lines or a patient-derived xenograft. CONCLUSIONS: Galunisertib suppresses activation of SMAD2 in neuroblastomas and aNK cells, restores NK cytotoxic mechanisms, and increases the efficacy of dinutuximab with aNK cells against neuroblastoma tumors. Clin Cancer Res; 23(3); 804-13. ©2016 AACRSee related commentary by Zenarruzabeitia et al., p. 615.

The clinical management and outcomes of cervical neuroblastic tumors.

BACKGROUND: Although patients with peripheral neuroblastoma (NB; pelvic and thoracic) typically have better outcomes and less aggressive disease compared with patients with abdominal disease, little has been published with regard to the management and outcomes of patients with cervical NB. Herein, we sought to determine the characteristics of cervical neuroblastic tumors and the effect of extent of resection on survival and outcomes. METHODS: We performed a retrospective review of 325 children with neuroblastic tumors at Children's Hospital Los Angeles over a 15-y period (January 1990-February 2015). Data collected from the medical record included location of tumor, age at diagnosis, age at resection, extent of resection, chemotherapy course, International Neuroblastoma Staging System stage, histologic International Neuroblastoma Pathology Classification, and MYCN amplification, a poor prognostic marker. Outcome variables included postoperative complications and overall survival. RESULTS: Twelve patients (3.6%) were found to have cervical neuroblastic tumors (nine NBs, one ganglioneuroblastoma, and two ganglioneuromas). All had favorable histology, and none (0/12) had MYCN amplification. Of the NB patients, four of nine patients underwent resection, whereas the other five underwent biopsy followed by chemotherapy or observation alone. Of the 12 total patients, six underwent gross total resection, four (67%) of which developed complications. At a median follow-up of 4.4 y, there were no recurrences or deaths. CONCLUSIONS: Cervical neuroblastic tumors represent favorable lesions with good outcomes similar to other peripheral neuroblastic tumors. In our study, survival was excellent regardless of extent of tumor resection. Based on our data, we recommend a minimally aggressive surgical approach in managing children with cervical neuroblastic tumors.

A novel minimal residual disease model of neuroblastoma in mice.

INTRODUCTION: Patients with high-risk neuroblastoma rarely succumb to their primary tumor but rather from relapsed metastatic disease after surgery. We, therefore, sought to create an in vivo model of minimal residual disease (MRD), which clinically replicates tumor recurrence and metastasis after surgical resection. METHODS: Neuroblastoma cell lines CHLA-255, CHLA-136, and SH-SY5Y were used. After establishing orthotopic xenografts, mice were divided into control tumor group (sham operation at 14days) and tumor resection group (resection at 14days). Mice were monitored by bioluminescent imaging and sacrificed when institutional criteria for euthanasia were met. RESULTS: In the CHLA-255 and CHLA-136 cell lines, mice experienced significantly longer survival following tumor resection (p<0.007). There was no survival benefit seen in the SH-SY5Y cell line (p=0.29). Bioluminescent imaging demonstrated metastatic disease in 100% of all tumor resection mice and varying rates of metastasis in control mice (4 of 5 CHLA-255, 2 of 4 CHLA-136, and 7 of 7 SH-SY5Y). CONCLUSION: In this study, we describe a novel neuroblastoma model of MRD in mice. This MRD model serves as an innovative means to test preclinical therapies as well as elucidate mechanisms of metastatic disease in experimental neuroblastoma.

The xenoantibody response and immunoglobulin gene expression profile of cynomolgus monkeys transplanted with hDAF-transgenic porcine hearts.

BACKGROUND: Recent work has indicated a role for anti-Gal alpha 1-3Gal (Gal) and anti-non-Gal xenoantibodies in the primate humoral rejection response against human-decay accelerating factor (hDAF) transgenic pig organs. Our laboratory has shown that anti-porcine xenograft antibodies in humans and non-human primates are encoded by a small number of germline IgV(H) progenitors. In this study, we extended our analysis to identify the IgV(H) genes encoding xenoantibodies in immunosuppressed cynomolgus monkeys (Macaca fascicularis) transplanted with hDAF-transgenic pig organs. METHODS: Three immunosuppressed monkeys underwent heterotopic heart transplantation with hDAF porcine heart xenografts. Two of three animals were given GAS914, a poly-L-lysine derivative shown to bind to anti-Gal xenoantibodies and neutralize them. One animal rejected its heart at post-operative day (POD) 39; a second animal rejected the transplanted heart at POD 78. The third monkey was euthanized on POD 36 but the heart was not rejected. Peripheral blood leukocytes (PBL) and serum were obtained from each animal before and at multiple time points after transplantation. We analyzed the immune response by enzyme-linked immunosorbent assay (ELISA) to confirm whether anti-Gal or anti-non-Gal xenoantibodies were induced after graft placement. Immunoglobulin heavy-chain gene (V(H)) cDNA libraries were then produced and screened. We generated soluble single-chain antibodies (scFv) to establish the binding specificity of the cloned immunoglobulin genes. RESULTS: Despite immunosuppression, which included the use of the polymer GAS914, the two animals that rejected their hearts showed elevated levels of cytotoxic anti-pig red blood cell (RBC) antibodies and anti-pig aortic endothelial cell (PAEC) antibodies. The monkey that did not reject its graft showed a decline in serum anti-RBC, anti-PAEC, and anti-Gal xenoantibodies when compared with pre-transplant levels. A V(H)3 family gene with a high level of sequence similarity to an allele of V(H)3-11, designated V(H)3-11(cyno), was expressed at elevated levels in the monkey that was not given GAS914 and whose graft was not rejected until POD 78. IgM but not IgG xenoantibodies directed at N-acetyl lactosamine (a precursor of the Gal epitope) were also induced in this animal. We produced soluble scFv from this new gene to determine whether this antibody could bind to the Gal carbohydrate, and demonstrated that this protein was capable of blocking the binding of human serum xenoantibody to Gal oligosaccharide, as had previously been shown with human V(H)3-11 scFv. CONCLUSIONS: DAF-transgenic organs transplanted into cynomolgus monkeys induce anti-Gal and anti-non-Gal xenoantibody responses mediated by both IgM and IgG xenoantibodies. Anti-non-Gal xenoantibodies are induced at high levels in animals treated with GAS914. Antibodies that bind to the Gal carbohydrate and to N-acetyl lactosamine are induced in the absence of GAS914 treatment. The animal whose heart remained beating for 78 days demonstrated increased usage of an antibody encoded by a germline progenitor that is structurally related, but distinct from IGHV311. This antibody binds to the Gal carbohydrate but does not induce the rapid rejection of the xenograft when expressed at high levels as early as day 8 post-transplantation.