Genotypes of NK cell KIR receptors, their ligands, and Fcγ receptors in the response of neuroblastoma patients to Hu14.18-IL2 immunotherapy

Natural killer cell-based therapies in neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor of childhood forming around 15 % of all pediatric tumors. Despite advances in the treatment of NB, high-risk patients still face a grave prognosis. Adoptive cell therapies based on NK cells are becoming an assistive treatment for such cases. Moreover, there is also evidence that NKT-based therapies have promising results in the management of NB. Lower complications in comparison with adoptive T cell therapies, various cell sources, and miscellaneous tumor recognition mechanisms are some of the advantages of NK- and NKT-based therapies. This review is dedicated to searching for recent advances in this field.

Natural killer cells in neuroblastoma: immunological insights and therapeutic perspectives

Natural killer (NK) cells have multifaceted roles within the complex tumor milieu. They are pivotal components of innate immunity and shape the dynamic landscape of tumor-immune cell interactions, and thus can be leveraged for use in therapeutic interventions. NK-based immunotherapies have had remarkable success in hematological malignancies, but these therapies are met with many challenges in solid tumors, including neuroblastoma (NB), a childhood tumor arising from the sympathetic nervous system. With a focus on NB, this review outlines the mechanisms employed by NK cells to recognize and eliminate malignant cells, delving into the dynamic relationship between ligand-receptor interactions, cytokines, and other molecules that facilitate the cross talk between NK and NB cells. We discuss the immunomodulatory functions of NK cells and the mechanisms that contribute to loss of this immunosurveillance in NB, with a focus on how this dynamic has been utilized in recent immunotherapy advancements for NB.

Effectiveness of radiotherapy and targeted radionuclide therapy for melanoma in preclinical mouse models: A combination treatments overview

Cutaneous melanoma is an aggressive and highly metastatic skin cancer. In recent years, immunotherapy and targeted small-molecule inhibitors have improved the overall survival of patients. Unfortunately, most patients in advanced stages of disease exhibit either intrinsically resistant or rapidly acquire resistance to these approved treatments. However, combination treatments have emerged to overcome resistance, and novel treatments based on radiotherapy (RT) and targeted radionuclide therapy (TRT) have been developed to treat melanoma in the preclinical mouse model, raising the question of whether synergy in combination therapies may motivate and increase their use as primary treatments for melanoma. To help clarify this question, we reviewed the studies in preclinical mouse models where they evaluated RT and TRT in combination with other approved and unapproved therapies from 2016 onwards, focusing on the type of melanoma model used (primary tumor and or metastatic model). PubMed® was the database in which the search was performed using mesh search algorithms resulting in 41 studies that comply with the inclusion rules of screening. Studies reviewed showed that synergy with RT or TRT had strong antitumor effects, such as tumor growth inhibition and fewer metastases, also exhibiting systemic protection. In addition, most studies were carried out on antitumor response for the implanted primary tumor, demonstrating that more studies are needed to evaluate these combined treatments in metastatic models on long-term protocols.

Biology of GD2 ganglioside: implications for cancer immunotherapy

Part of the broader glycosphingolipid family, gangliosides are composed of a ceramide bound to a sialic acid-containing glycan chain, and locate at the plasma membrane. Gangliosides are produced through sequential steps of glycosylation and sialylation. This diversity of composition is reflected in differences in expression patterns and functions of the various gangliosides. Ganglioside GD2 designates different subspecies following a basic structure containing three carbohydrate residues and two sialic acids. GD2 expression, usually restrained to limited tissues, is frequently altered in various neuroectoderm-derived cancers. While GD2 is of evident interest, its glycolipid nature has rendered research challenging. Physiological GD2 expression has been linked to developmental processes. Passing this stage, varying levels of GD2, physiologically expressed mainly in the central nervous system, affect composition and formation of membrane microdomains involved in surface receptor signaling. Overexpressed in cancer, GD2 has been shown to enhance cell survival and invasion. Furthermore, binding of antibodies leads to immune-independent cell death mechanisms. In addition, GD2 contributes to T-cell dysfunction, and functions as an immune checkpoint. Given the cancer-associated functions, GD2 has been a source of interest for immunotherapy. As a potential biomarker, methods are being developed to quantify GD2 from patients' samples. In addition, various therapeutic strategies are tested. Based on initial success with antibodies, derivates such as bispecific antibodies and immunocytokines have been developed, engaging patient immune system. Cytotoxic effectors or payloads may be redirected based on anti-GD2 antibodies. Finally, vaccines can be used to mount an immune response in patients. We review here the pertinent biological information on GD2 which may be of use for optimizing current immunotherapeutic strategies.

Principles and current clinical landscape of NK cell engaging bispecific antibody against cancer

Monoclonal antibody-based targeted therapies have greatly improved treatment options for patients by binding to the innate immune system. However, the long-term efficacy of such antibodies is limited by mechanisms of drug resistance. Over the last 50 years, with advances in protein engineering technology, more and more bispecific antibody (bsAb) platforms have been engineered to meet diverse clinical needs. Bispecific NK cell engagers (BiKEs) or tri-specific NK cell engagers (TriKEs) allow for direct targeting of immune cells to tumors, and therefore resistance and serious adverse effects are greatly reduced. Many preclinical and clinical trials are currently underway, depicting the promise of antibody-based natural killer cell engager therapeutics. In this review, we compile worldwide efforts to explore the involvement of NK cells in bispecific antibodies. With a particular emphasis on lessons learned, we focus on preclinical and clinical studies in malignancies and discuss the reasons for the limited success of NK-cell engagers against solid tumors, offering plausible new ideas for curing some advanced cancers shortly.

Aberrant Glycosylation as Immune Therapeutic Targets for Solid Tumors

Glycosylation occurs at all major types of biomolecules, including proteins, lipids, and RNAs to form glycoproteins, glycolipids, and glycoRNAs in mammalian cells, respectively. The carbohydrate moiety, known as glycans on glycoproteins and glycolipids, is diverse in their compositions and structures. Normal cells have their unique array of glycans or glycome which play pivotal roles in many biological processes. The glycan structures in cancer cells, however, are often altered, some having unique structures which are termed as tumor-associated carbohydrate antigens (TACAs). TACAs as tumor biomarkers are glycan epitopes themselves, or glycoconjugates. Some of those TACAs serve as tumor glyco-biomarkers in clinical practice, while others are the immune therapeutic targets for treatment of cancers. A monoclonal antibody (mAb) to GD2, an intermediate of sialic-acid containing glycosphingolipids, is an example of FDA-approved immune therapy for neuroblastoma indication in young adults and many others. Strategies for targeting the aberrant glycans are currently under development, and some have proceeded to clinical trials. In this review, we summarize the currently established and most promising aberrant glycosylation as therapeutic targets for solid tumors.

Associations between KIR/KIR-ligand genotypes and clinical outcome for patients with advanced solid tumors receiving BEMPEG plus nivolumab combination therapy in the PIVOT-02 trial

Bempegaldesleukin (BEMPEG), a CD122-preferential IL2 pathway agonist, has been shown to induce proliferation and activation of NK cells. NK activation is dependent on the balance of inhibitory and excitatory signals transmitted by NK receptors, including Fc-gamma receptors (FCγRs) and killer immunoglobulin-like receptors (KIRs) along with their KIR-ligands. The repertoire of KIRs/KIR-ligands an individual inherits and the single-nucleotide polymorphisms (SNPs) of FCγRs can influence NK function and affect responses to immunotherapies. In this retrospective analysis of the single-arm PIVOT-02 trial, 200 patients with advanced solid tumors were genotyped for KIR/KIR-ligand gene status and FCγR SNP status and evaluated for associations with clinical outcome. Patients with inhibitory KIR2DL2 and its ligand (HLA-C1) observed significantly greater tumor shrinkage (TS, median change -13.0 vs. 0%) and increased PFS (5.5 vs. 3.3 months) and a trend toward improved OR (31.2 vs. 19.5%) compared to patients with the complementary genotype. Furthermore, patients with KIR2DL2 and its ligand together with inhibitory KIR3DL1 and its ligand (HLA-Bw4) had improved OR (36.5 vs. 19.6%), greater TS (median change -16.1 vs. 0%), and a trend toward prolonged PFS (8.4 vs. 3.6 months) as compared to patients with the complementary genotype. FCγR polymorphisms did not influence OR/PFS/TS.These data show that clinical response to BEMPEG plus nivolumab treatment in the PIVOT-02 trial may be associated with the repertoire of KIR/KIR-ligands an individual inherits. Further investigation and validation of these results may enable KIR/KIR-ligand genotyping to be utilized prospectively for identifying patients likely to benefit from certain cancer immunotherapy regimens.

MHC Class I Ligands of Rhesus Macaque Killer Cell Ig-like Receptors

Definition of MHC class I ligands of rhesus macaque killer cell Ig-like receptors (KIRs) is fundamental to NK cell biology in this species as an animal model for infectious diseases, reproductive biology, and transplantation. To provide a more complete foundation for studying NK cell responses, rhesus macaque KIRs representing common allotypes of lineage II KIR genes were tested for interactions with MHC class I molecules representing diverse Macaca mulatta (Mamu)-A, -B, -E, -F, -I, and -AG alleles. KIR-MHC class I interactions were identified by coincubating reporter cell lines bearing chimeric KIR-CD3ζ receptors with target cells expressing individual MHC class I molecules and were corroborated by staining with KIR IgG-Fc fusion proteins. Ligands for 12 KIRs of previously unknown specificity were identified that fell into three general categories: interactions with multiple Mamu-Bw4 molecules, interactions with Mamu-A-related molecules, including allotypes of Mamu-AG and the hybrid Mamu-B*045:03 molecule, or interactions with Mamu-A1*012:01. Whereas most KIRs found to interact with Mamu-Bw4 are inhibitory, most of the KIRs that interact with Mamu-AG are activating. The KIRs that recognize Mamu-A1*012:01 belong to a phylogenetically distinct group of macaque KIRs with a 3-aa deletion in the D0 domain that is also present in human KIR3DL1/S1 and KIR3DL2. This study more than doubles the number of rhesus macaque KIRs with defined MHC class I ligands and identifies interactions with Mamu-AG, -B*045, and -A1*012. These findings support overlapping, but nonredundant, patterns of ligand recognition that reflect extensive functional diversification of these receptors.

KIR/KIR-ligand genotypes and clinical outcomes following chemoimmunotherapy in patients with relapsed or refractory neuroblastoma: a report from the Children's Oncology Group

BACKGROUND

In the Children's Oncology Group ANBL1221 phase 2 trial for patients with first relapse/first declaration of refractory high-risk neuroblastoma, irinotecan and temozolomide (I/T) combined with either temsirolimus (TEMS) or immunotherapy (the anti-GD2 antibody dinutuximab (DIN) and granulocyte macrophage colony stimulating factory (GM-CSF)) was administered. The response rate among patients treated with I/T/DIN/GM-CSF in the initial cohort (n=17) was 53%; additional patients were enrolled to permit further evaluation of this chemoimmunotherapy regimen. Potential associations between immune-related biomarkers and clinical outcomes including response and survival were evaluated.

METHODS

Patients were evaluated for specific immunogenotypes that influence natural killer (NK) cell activity, including killer immunoglobulin-like receptors (KIRs) and their ligands, Fc gamma receptors, and NCR3. Total white cells and leucocyte subsets were assessed via complete blood counts, and flow cytometry of peripheral blood mononuclear cells was performed to assess the potential association between immune cell subpopulations and surface marker expression and clinical outcomes. Appropriate statistical tests of association were performed. The Bonferroni correction for multiple comparisons was performed where indicated.

RESULTS

Of the immunogenotypes assessed, the presence or absence of certain KIR and their ligands was associated with clinical outcomes in patients treated with chemoimmunotherapy rather than I/T/TEMS. While median values of CD161, CD56, and KIR differed in responders and non-responders, statistical significance was not maintained in logistic regression models. White cell and neutrophil counts were associated with differences in survival outcomes, however, increases in risk of event in patients assigned to chemoimmunotherapy were not clinically significant.

CONCLUSIONS

These findings are consistent with those of prior studies showing that KIR/KIR-ligand genotypes are associated with clinical outcomes following anti-GD2 immunotherapy in children with neuroblastoma. The current study confirms the importance of KIR/KIR-ligand genotype in the context of I/T/DIN/GM-CSF chemoimmunotherapy administered to patients with relapsed or refractory disease in a clinical trial. These results are important because this regimen is now widely used for treatment of patients at time of first relapse/first declaration of refractory disease. Efforts to assess the role of NK cells and genes that influence their function in response to immunotherapy are ongoing.

TRIAL REGISTRATION NUMBER

NCT01767194.

Strategies for Potentiating NK-Mediated Neuroblastoma Surveillance in Autologous or HLA-Haploidentical Hematopoietic Stem Cell Transplants

Simple Summary

High-risk neuroblastomas (HR-NB) are malignant tumors of childhood that are treated with a very aggressive and life-threatening approach; this includes autologous hemopoietic stem cell transplantation (HSCT) and the infusion of a mAb targeting the GD2 tumor-associated antigen. Although the current treatment provided benefits, the 5-year overall survival remains below 50% due to relapses and refractoriness to therapy. Thus, there is an urgent need to ameliorate the standard therapeutic protocol, particularly improving the immune-mediated anti-tumor responses. Our review aims at summarizing and critically discussing novel immunotherapeutic strategies in HR-NB, including NK cell-based therapies and HLA-haploidentical HSCT from patients’ family.

Abstract

High-risk neuroblastomas (HR-NB) still have an unacceptable 5-year overall survival despite the aggressive therapy. This includes standardized immunotherapy combining autologous hemopoietic stem cell transplantation (HSCT) and the anti-GD2 mAb. The treatment did not significantly change for more than one decade, apart from the abandonment of IL-2, which demonstrated unacceptable toxicity. Of note, immunotherapy is a promising therapeutic option in cancer and could be optimized by several strategies. These include the HLA-haploidentical αβT/B-depleted HSCT, and the antibody targeting of novel NB-associated antigens such as B7-H3, and PD1. Other approaches could limit the immunoregulatory role of tumor-derived exosomes and potentiate the low antibody-dependent cell cytotoxicity of CD16 dim/neg NK cells, abundant in the early phase post-transplant. The latter effect could be obtained using multi-specific tools engaging activating NK receptors and tumor antigens, and possibly holding immunostimulatory cytokines in their construct. Finally, treatments also consider the infusion of novel engineered cytokines with scarce side effects, and cell effectors engineered with chimeric antigen receptors (CARs). Our review aims to discuss several promising strategies that could be successfully exploited to potentiate the NK-mediated surveillance of neuroblastoma, particularly in the HSCT setting. Many of these approaches are safe, feasible, and effective at pre-clinical and clinical levels.

Phase 2 study of anti-disialoganglioside antibody, dinutuximab, in combination with GM-CSF in patients with recurrent osteosarcoma: A report from the Children's Oncology Group

PURPOSE

Novel effective therapies are urgently needed in recurrent osteosarcoma. GD2 is expressed in human osteosarcoma tumours and cell lines. This study evaluated the disease control rate (DCR) in patients with recurrent osteosarcoma treated with the anti-GD2 antibody dinutuximab plus cytokine therapy as compared to historical outcomes.

METHODS

AOST1421 was a single-arm Phase 2 study for patients with recurrent pulmonary osteosarcoma in complete surgical remission. Patients received up to five cycles of dinutuximab (70 mg/m2/cycle) with granulocyte-macrophage colony-stimulating factor (GM-CSF). Two different dinutuximab infusion schedules were studied: 35 mg/m2/day over 20 h (2 days) and 17.5 mg/m2/day over 10 h (4 days). Primary end point was DCR, defined as a proportion of patients event free at 12 months from enrolment. The historical benchmark was 12-month DCR of 20% (95% CI 10-34%). Dinutuximab would be considered effective if ≥ 16/39 patients remained event free. Secondary objectives included toxicity evaluation and pharmacokinetics.

RESULTS

Thirty-nine eligible patients were included in the outcome analysis. Dinutuximab did not demonstrate evidence of efficacy as 11/39 patients remained event free for a DCR of 28.2% (95% CI 15-44.9%). One of 136 administered therapy cycles met criteria for unacceptable toxicity when a patient experienced sudden death of unknown cause. Other ≥ Grade 3 toxicities included pain, diarrhoea, hypoxia, and hypotension. Pharmacokinetic parameters were similar in the two schedules.

CONCLUSIONS

The combination of dinutuximab with GM-CSF did not significantly improve DCR in recurrent osteosarcoma. Dinutuximab toxicity and pharmacokinetics in adolescent and young adult osteosarcoma patients were similar to younger patients. Other strategies for targeting GD2 in osteosarcoma are being developed.

Immune checkpoint molecules in neuroblastoma: A clinical perspective

High-risk neuroblastoma (NB) is challenging to treat with 5-year long-term survival in patients remaining below 50% and low chances of survival after tumor relapse or recurrence. Different strategies are being tested or under evaluation to destroy resistant tumors and improve survival outcomes in NB patients. Immunotherapy, which uses certain parts of a person's immune system to recognize or kill tumor cells, effectively improves patient outcomes in several types of cancer, including NB. One of the immunotherapy strategies is to block immune checkpoint signaling in tumors to increase tumor immunogenicity and anti-tumor immunity. Immune checkpoint proteins put brakes on immune cell functions to regulate immune activation, but this activity is exploited in tumors to evade immune surveillance and attack. Immune checkpoint proteins play an essential role in NB biology and immune escape mechanisms, which makes these tumors immunologically cold. Therapeutic strategies to block immune checkpoint signaling have shown promising outcomes in NB but only in a subset of patients. However, combining immune checkpoint blockade with other therapies, including conjugated antibody-based immunotherapy, radioimmunotherapy, tumor vaccines, or cellular therapies like modified T or natural killer (NK) cells, has shown encouraging results in enhancing anti-tumor immunity in the preclinical setting. An analysis of publicly available dataset using computational tools has unraveled the complexity of multiple cancer including NB. This review comprehensively summarizes the current information on immune checkpoint molecules, their biology, role in immune suppression and tumor development, and novel therapeutic approaches combining immune checkpoint inhibitors with other therapies to combat high-risk NB.

P10s-PADRE vaccine combined with neoadjuvant chemotherapy in ER-positive breast cancer patients induces humoral and cellular immune responses

Breast cancer patients diagnosed with HR+/HER2– tumors face a persistent risk of distant recurrence long after completion of their treatment. Strategies to induce anti-tumor immune responses could complement standard-of-care therapies for these patients. The current study was performed to examine the feasibility, safety and immunogenicity of adding P10s-PADRE to standard-of-care chemotherapy in HR+/HER2− early-stage breast cancer patients. Twenty-five subjects were treated in a single-arm Phase Ib clinical trial. Five different immunization schedules were considered to evaluate the feasibility of eliciting an immune response. The primary immunogenicity endpoint was antibody titer. The expression of several activation markers on natural killer (NK) cells and serum concentrations of Th1/Th2 cytokines were also examined. The percentage of tumor-infiltrating lymphocytes (TILs) was determined. Antibody response was superior in schedule C where 3 weekly immunizations preceded the first dose of chemotherapy. A significant change in CD16, NKp46 and CD94 expression levels on NK cells and a rise in serum content of IFN-γ was observed after treatment. Schedule C showed an increase in TILs in residual lesions. The combination therapy is safe and immunogenic with treatment schedule C being immunologically promising. Randomized trials focused on long-term survival outcomes are needed to evaluate clinical benefits.

Combining Immunocytokine and Ex Vivo Activated NK Cells as a Platform for Enhancing Graft-Versus-Tumor Effects Against GD2+ Murine Neuroblastoma

Management for high-risk neuroblastoma (NBL) has included autologous hematopoietic stem cell transplant (HSCT) and anti-GD2 immunotherapy, but survival remains around 50%. The aim of this study was to determine if allogeneic HSCT could serve as a platform for inducing a graft-versus-tumor (GVT) effect against NBL with combination immunocytokine and NK cells in a murine model. Lethally irradiated C57BL/6 (B6) x A/J recipients were transplanted with B6 bone marrow on Day +0. On day +10, allogeneic HSCT recipients were challenged with NXS2, a GD2+ NBL. On days +14-16, mice were treated with the anti-GD2 immunocytokine hu14.18-IL2. In select groups, hu14.18-IL2 was combined with infusions of B6 NK cells activated with IL-15/IL-15Rα and CD137L ex vivo. Allogeneic HSCT alone was insufficient to control NXS2 tumor growth, but the addition of hu14.18-IL2 controlled tumor growth and improved survival. Adoptive transfer of ex vivo CD137L/IL-15/IL-15Rα activated NK cells with or without hu14.18-IL2 exacerbated lethality. CD137L/IL-15/IL-15Rα activated NK cells showed enhanced cytotoxicity and produced high levels of TNF-α in vitro, but induced cytokine release syndrome (CRS) in vivo. Infusing Perforin-/- CD137L/IL-15/IL-15Rα activated NK cells had no impact on GVT, whereas TNF-α-/- CD137L/IL-15/IL-15Rα activated NK cells improved GVT by decreasing peripheral effector cell subsets while preserving tumor-infiltrating lymphocytes. Depletion of Ly49H+ NK cells also improved GVT. Using allogeneic HSCT for NBL is a viable platform for immunocytokines and ex vivo activated NK cell infusions, but must be balanced with induction of CRS. Regulation of TNFα or activating NK subsets may be needed to improve GVT effects.

Downregulation of NKG2DLs by TGF-β in human lung cancer cells

Background

Transforming growth factor beta (TGF-β) is a typical immuno-inhibitory cytokine and highly secreted by lung cancer cells. It was supposed that its immunosuppressive effects to NK cell might be related with the altered expression of activating and inhibitory molecules in lung cancer cells. In this study, we examined the expression of NKG2DLs, PD-L1 and PD-L2 in lung cancer cells after treatment of TGF-β and a TGF-β inhibitor, Galunisertib (LY2157299).

Results

TGF-β reduced the level of surface proteins of five NKG2DLs without altered transcription levels in lung cancer cells. Galunisertib reversed the effect of TGF-β on the expression of NKG2DLs. Since MMP inhibitors, MMPi III and MMP2 inhibitor I, restored the reduced expression of NKG2DLs after treatment of TGF-β, it was thought that TGF-β induced the expression of MMP2 which facilitated the shedding of the NKG2DLs in cancer cells. However, the expression of PD-L1, L2 were not changed by treatment with TGF-β or Galunisertib.

Conclusions

Therefore, inhibition of TGF-β might reverse the immunosuppressive status on immune cells and restore NK cell mediated anticancer immune responses by upregulation of NKG2DLs in cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00434-8.

Low number of KIR ligands in lymphoma patients favors a good rituximab-dependent NK cell response

The antibody-dependent cellular cytotoxicity (ADCC) effector function of natural killer (NK) cells is one of the known mechanisms of action for rituximab-based anti-cancer immunotherapy. Inhibition of the ADCC function of NK cells through interactions between inhibitory killer cell immunoglobulin-like receptors (KIRs) and HLA class I ligands is associated with resistance of cancers to rituximab. In this study, we deeply investigated the impact of KIR, HLA class I, and CD16 genotypes on rituximab-dependent NK cell responses in both an in vitro cellular model from healthy blood donors and ex vivo rituximab-treated non-Hodgkin lymphoma (NHL) patients. We highlight that an HLA environment with limited KIR ligands is beneficial to promoting a higher frequency of KIR⁺ NK cells including both educated and uneducated NK cells, two NK cell compartments that demonstrate higher rituximab-dependent degranulation than KIR⁻ NK cells. In contrast, a substantial KIR ligand environment favors a higher frequency of poorly effective KIR⁻ NK cells and numerous functional KIR/HLA inhibitions of educated KIR⁺ NK cells. These phenomena explain why NHL patients with limited KIR ligands respond better to rituximab. In this HLA environment, CD16 polymorphism appears to have a collateral effect. Furthermore, we show the synergic effect of KIR2DS1, which strongly potentiates NK cell ADCC from C2⁻ blood donors against C2⁺ target cells. Taken together, these results pave the way for stronger prediction of rituximab responses for NHL patients. HLA class I typing and peripheral blood KIR⁺ NK cell frequency could be simple and useful markers for predicting rituximab response.

Natural killer cell exhaustion in lung cancer

OBJECTIVES

Lung cancer is one of the most frequently diagnosed cancers worldwide. However, the potential causes of lung cancer oncogenesis are still unclear. This study aims to explore the phenomenon and mechanism of NK cell exhaustion in lung cancer and lay the foundation for developing a targeting strategy to ameliorate immune cell exhaustion in cancer.

MATERIALS AND METHODS

NK cells were isolated from the blood samples of lung cancer patients and healthy volunteers. After culture in vitro, the colony forming ability, cytotoxicity, apoptosis and receptor expression of NK cells in the peripheral blood from the lung cancer patients and the volunteers were analyzed by flow cytometry and the corresponding methods. The correlation between the NK cell profile and lung cancer occurrence was analyzed as well.

RESULTS

The colony formation and cytotoxicity of the NK cells from the lung cancer group were significantly decreased compared to whose of the NK cells from volunteers. The expression of NKG2A was upregulated and CD226 was downregulated significantly in the lung cancer group compared with the control group. Furthermore, through correlation analysis, the colony forming level, cytotoxicity and CD226 expression level were significantly negatively correlated with lung cancer, and the expression level of NKG2A was significantly positively correlated with lung cancer. Moreover, the impaired colony formation of NK cells was significantly correlated with NK cell functional exhaustion in lung cancer.

CONCLUSIONS

The downregulated CD226 expression and the upregulated NKG2A expression may serve as potential markers of NK cells exhaustion in lung cancer.

Utilizing Immunocytokines for Cancer Therapy

Cytokine therapy for cancer has indicated efficacy in certain diseases but is generally accompanied by severe toxicity. The field of antibody-cytokine fusion proteins (immunocytokines) arose to target these effector molecules to the tumor environment in order to expand the therapeutic window of cytokine therapy. Pre-clinical evidence has shown the increased efficacy and decreased toxicity of various immunocytokines when compared to their cognate unconjugated cytokine. These anti-tumor properties are markedly enhanced when combined with other treatments such as chemotherapy, radiotherapy, and checkpoint inhibitor antibodies. Clinical trials that have continued to explore the potential of these biologics for cancer therapy have been conducted. This review covers the in vitro, in vivo, and clinical evidence for the application of immunocytokines in immuno-oncology.

Natural Killer cells and monoclonal antibodies: Two partners for successful antibody dependent cytotoxicity against tumor cells

Monoclonal antibodies targeting tumors are one of the most important discoveries in the field of cancer. Although several effective antibodies have been developed, a relapse may occur. One of their mechanisms of action is Antibody Dependent Cell Cytotoxicity (ADCC), by engaging the Fc γ receptor CD16 expressing Natural Killer cells, innate lymphoid cells involved in cancer immunosurveillance and able to kill tumor cells. A lack of NK cells observed in many cancers may therefore be a cause of the low efficacy of antibodies observed in some clinical situations. Here we review clear evidences of the essential partnership between NK cells and antibodies showed in vitro, in vivo, and in clinical trials in different indications, describe the hurdles and ways to enhance ADCC and the evolution of monoclonal antibody therapy. NK cell adoptive immunotherapy combined with monoclonal antibodies may overcome the resistance to the treatment and enhance their efficacy.

Pembrolizumab plus allogeneic NK cells in advanced non-small cell lung cancer patients

BACKGROUNDThe anti-programmed cell death 1 (anti-PD-1) antibody pembrolizumab is clinically active against non-small cell lung cancer (NSCLC). In addition to T cells, human natural killer (NK) cells, reported to have the potential to prolong the survival of patients with advanced NSCLC, also express PD-1. This study aimed to investigate the safety and efficacy of pembrolizumab plus allogeneic NK cells in patients with previously treated advanced NSCLC.METHODSIn total, 109 enrolled patients with a programmed death ligand 1 (PD-L1) tumor proportion score (TPS) of 1% or higher were randomly allocated to group A (n = 55 patients given pembrolizumab plus NK cells) or group B (n = 54 patients given pembrolizumab alone). The patients received i.v. pembrolizumab (10 mg/kg) once every 3 weeks and continued treatment until the occurrence of tumor progression or unacceptable toxicity. The patients in group A continuously received 2 cycles of NK cell therapy as 1 course of treatment.RESULTSIn our study, patients in group A had longer survival than did patients in group B (median overall survival [OS]: 15.5 months vs. 13.3 months; median progression-free survival [PFS]: 6.5 months vs. 4.3 months; P < 0.05). In group A patients with a TPS of 50% or higher, the median OS and PFS was significantly longer. Moreover, the patients in group A treated with multiple courses of NK cell infusion had better OS (18.5 months) than did those who received a single course of NK cell infusion (13.5 months).CONCLUSIONPembrolizumab plus NK cell therapy yielded improved survival benefits in patients with previously treated PD-L1+ advanced NSCLC.TRIAL REGISTRATIONClinicalTrials.gov NCT02843204.FUNDINGThis work was supported by grants from the National Natural Science Foundation of China (NSFC) - Guangdong Joint Foundation of China (no. U1601225); the NSFC (no. 81671965); the Guangdong Provincial Key Laboratory Construction Project of China (no. 2017B030314034); and the Key Scientific and Technological Program of Guangzhou City (no. 201607020016).

The Current Landscape of Antibody-based Therapies in Solid Malignancies

Over the past three decades, monoclonal antibodies (mAbs) have revolutionized the landscape of cancer therapy. Still, this benefit remains restricted to a small proportion of patients due to moderate response rates and resistance emergence. The field has started to embrace better mAb-based formats with advancements in molecular and protein engineering technologies. The development of a therapeutic mAb with long-lasting clinical impact demands a prodigious understanding of target antigen, effective mechanism of action, gene engineering technologies, complex interplay between tumor and host immune system, and biomarkers for prediction of clinical response. This review discusses the various approaches used by mAbs for tumor targeting and mechanisms of therapeutic resistance that is not only caused by the heterogeneity of tumor antigen, but also the resistance imposed by tumor microenvironment (TME), including inefficient delivery to the tumor, alteration of effector functions in the TME, and Fc-gamma receptor expression diversity and polymorphism. Further, this article provides a perspective on potential strategies to overcome these barriers and how diagnostic and prognostic biomarkers are being used in predicting response to mAb-based therapies. Overall, understanding these interdependent parameters can improve the current mAb-based formulations and develop novel mAb-based therapeutics for achieving durable clinical outcomes in a large subset of patients.

The immune landscape of neuroblastoma: Challenges and opportunities for novel therapeutic strategies in pediatric oncology

Immunotherapy holds great promise for the treatment of pediatric cancers. In neuroblastoma, the recent implementation of anti-GD2 antibody Dinutuximab into the standard of care has improved patient outcomes substantially. However, 5-year survival rates are still below 50% in patients with high-risk neuroblastoma, which has sparked investigations into novel immunotherapeutic approaches. T cell-engaging therapies such as immune checkpoint blockade, antibody-mediated therapy and adoptive T cell therapy have proven remarkably successful in a range of adult cancers but still meet challenges in pediatric oncology. In neuroblastoma, their limited success may be due to several factors. Neuroblastoma displays low immunogenicity due to its low mutational load and lack of MHC-I expression. Tumour infiltration by T and NK cells is especially low in high-risk neuroblastoma and is prognostic for survival. Only a small fraction of tumour-infiltrating lymphocytes shows tumour reactivity. Moreover, neuroblastoma tumours employ a variety of immune evasion strategies, including expression of immune checkpoint molecules, induction of immunosuppressive myeloid and stromal cells, as well as secretion of immunoregulatory mediators, which reduce infiltration and reactivity of immune cells. Overcoming these challenges will be key to the successful implementation of novel immunotherapeutic interventions. Combining different immunotherapies, as well as personalised strategies, may be promising approaches. We will discuss the composition, function and prognostic value of tumour-infiltrating lymphocytes (TIL) in neuroblastoma, reflect on challenges for immunotherapy, including a lack of TIL reactivity and tumour immune evasion strategies, and highlight opportunities for immunotherapy and future perspectives with regard to state-of-the-art developments in the tumour immunology space.

Evolving insights into the mechanisms of toxicity associated with immune checkpoint inhibitor therapy

Immune checkpoint inhibitors have emerged as a revolutionary treatment option for patients with various types of malignancy. Although these agents afford a significant improvement in outcomes for melanoma and other previously untreatable malignancies, their novel mechanism of action may predispose patients to immune-related adverse effects (irAEs). In the tumour neoantigen environment, these irAEs are due to the activation of the immune system by the blockade of suppressive checkpoints, leading to increases in T-cell activation and proliferation. IrAEs have been reported in almost any organ and at any point in time, even months to years after discontinuation of therapy. Certain populations with distinct physiological changes, genetic risk factors, and specific antigen exposures may be more highly predisposed to develop irAEs. This review discusses the incidence and mechanisms of irAEs and the relationship between host factors and irAE occurrence.

In situ vaccination at a peripheral tumor site augments response against melanoma brain metastases

BACKGROUND

Immune checkpoint inhibition (ICI) alone is not efficacious for a large number of patients with melanoma brain metastases. We previously established an in situ vaccination (ISV) regimen combining radiation and immunocytokine to enhance response to ICIs. Here, we tested whether ISV inhibits the development of brain metastases in a murine melanoma model.

METHODS

B78 (GD2+) melanoma 'primary' tumors were engrafted on the right flank of C57BL/6 mice. After 3-4 weeks, primary tumors were treated with ISV (radiation (12 Gy, day 1), α-GD2 immunocytokine (hu14.18-IL2, days 6-10)) and ICI (α-CTLA-4, days 3, 6, 9). Complete response (CR) was defined as no residual tumor observed at treatment day 90. Mice with CR were tested for immune memory by re-engraftment with B78 in the left flank and then the brain. To test ISV efficacy against metastases, tumors were also engrafted in the left flank and brain of previously untreated mice. Tumors were analyzed by quantitative reverse transcription-PCR, immunohistochemistry, flow cytometry and multiplex cytokine assay.

RESULTS

ISV+α-CTLA-4 resulted in immune memory and rejection of B78 engraftment in the brain in 11 of 12 mice. When B78 was engrafted in brain prior to treatment, ISV+α-CTLA-4 increased survival compared with ICI alone. ISV+α-CTLA-4 eradicated left flank tumors but did not elicit CR at brain sites when tumor cells were engrafted in brain prior to ISV. ISV+α-CTLA-4 increased CD8+ and CD4+ T cells in flank and brain tumors compared with untreated mice. Among ISV + α-CTLA-4 treated mice, left flank tumors showed increased CD8+ infiltration and CD8+:FOXP3+ ratio compared with brain tumors. Flank and brain tumors showed minimal differences in expression of immune checkpoint receptors/ligands or Mhc-1. Cytokine productions were similar in left flank and brain tumors in untreated mice. Following ISV+α-CTLA-4, production of immune-stimulatory cytokines was greater in left flank compared with brain tumor grafts.

CONCLUSION

ISV augmented response to ICIs in murine melanoma at brain and extracranial tumor sites. Although baseline tumor-immune microenvironments were similar at brain and extracranial tumor sites, response to ISV+α-CTLA-4 was divergent with reduced infiltration and activation of immune cells in brain tumors. Additional therapies may be needed for effective antitumor immune response against melanoma brain metastases.

CD155 immunoregulation as a target for natural killer cell immunotherapy in glioblastoma

Natural killer (NK) cells are powerful immune effectors, modulating their anti-tumor function through a balance activating and inhibitor ligands on their cell surface. Though still emerging, cancer immunotherapies utilizing NK cells are proving promising as a modality for the treatment of a number of solid tumors, including glioblastoma (GBM) and other gliomas, but are often limited due to complex immunosuppression associated with the GBM tumor microenvironment which includes overexpression of inhibitory receptors on GBM cells. CD155, or poliovirus receptor (PVR), has recently emerged as a pro-tumorigenic antigen, overexpressed on GBM and contributing to increased GBM migration and aggressiveness. CD155 has also been established as an immunomodulatory receptor, able to both activate NK cells through interactions with CD226 (DNAM-1) and CD96 and inhibit them through interaction with TIGIT. However, NK cell TIGIT expression has been shown to be upregulated in cancer, establishing CD155 as a predominantly inhibitory receptor within the context of GBM and other solid tumors, and rendering it of interest as a potential target for antigen-specific NK cell-based immunotherapy. This review will explore the function of CD155 within GBM as it relates to tumor migration and NK cell immunoregulation, as well as pre-clinical and clinical targeting of CD155/TIGIT and the potential that this pathway holds for the development of emerging NK cell-based immunotherapies.

Enhancing Neuroblastoma Immunotherapies by Engaging iNKT and NK Cells

Neuroblastoma (NB) is the most common extracranial solid tumor in children and, in the high-risk group, has a 5-year mortality rate of ~50%. The high mortality rate and significant treatment-related morbidities associated with current standard of care therapies belie the critical need for more tolerable and effective treatments for this disease. While the monoclonal antibody dinutuximab has demonstrated the potential for immunotherapy to improve overall NB outcomes, the 5-year overall survival of high-risk patients has not yet substantially changed. The frequency and type of invariant natural killer T cells (iNKTs) and natural killer cells (NKs) has been associated with improved outcomes in several solid and liquid malignancies, including NB. Indeed, iNKTs and NKs inhibit tumor associated macrophages (TAMs) and myeloid derived suppressor cells (MDSCs), kill cancer stem cells (CSCs) and neuroblasts, and robustly secrete cytokines to recruit additional immune effectors. These capabilities, and promising pre-clinical and early clinical data suggest that iNKT- and NK-based therapies may hold promise as both stand-alone and combination treatments for NB. In this review we will summarize the biologic features of iNKTs and NKs that confer advantages for NB immunotherapy, discuss the barriers imposed by the NB tumor microenvironment, and examine the current state of such therapies in pre-clinical models and clinical trials.

Dinutuximab Synergistically Enhances the Cytotoxicity of Natural Killer Cells to Retinoblastoma Through the Perforin-Granzyme B Pathway

Purpose

Conventional chemotherapy and enucleation usually fail to cure advanced retinoblastoma. We investigated the retinoblastoma immune microenvironment and the efficacy of the combination of dinutuximab and CD16-expressing NK-92MI (NK-92MI^hCD16-GFP) cells on retinoblastoma cells in this study.

Patients and Methods

Immunohistochemistry and flow cytometry (FC) were performed to assess the expression level of GD2 in retinoblastoma tissues and cells. Gene set enrichment analysis (GSEA), immunohistochemisrztry and immunocytochemistry were conducted to assess the retinoblastoma immune microenvironment and the integrity of the blood-retinal barrier (BRB). After overexpressing CD16 in NK-92MI cells, fluorescence-activated cell sorting (FACS) was applied to select the positive subpopulation. LDH assays and FC were used to detect LDH release and apoptosis in retinoblastoma cells subjected to a combination of dinutuximab and NK-92MI^hCD16-GFP cells. Finally, the release of perforin-granzyme B and the expression of CD107a in NK-92MI^hCD16-GFP stimulated by retinoblastoma cells were assessed via enzyme-linked immunosorbent assays (ELISAs) and FC in the presence of dinutuximab or an isotype control.

Results

GD2 was heterogeneously expressed in retinoblastoma tissues and cell lines and positively correlated with proliferation and staging. GSEA revealed the immunosuppressive status of retinoblastoma microenvironment. The immune cell profile of retinoblastoma tissues and vitreous bodies suggested BRB destruction. LDH release and apoptosis in retinoblastoma cells caused by NK-92MI^hCD16-GFP cells were significantly enhanced by dinutuximab. Finally, the release of perforin-granzyme B and the expression of CD107a in NK-92MI^hCD16-GFP cells stimulated by retinoblastoma cells were obviously increased by dinutuximab.

Conclusion

This study indicates that retinoblastoma impairs the integrity of the BRB and contributes to dysregulated immune cell infiltrates. GD2 is a specific target for natural killer (NK) cell-based immunotherapy and that the combination of dinutuximab and NK-92MI^hCD16-GFP cells exerts potent antitumor effects through antibody-dependent cell-mediated cytotoxicity.

Targets and Antibody Formats for Immunotherapy of Neuroblastoma

Neuroblastoma (NB) is a malignant embryonal tumor of the sympathetic nervous system that is most commonly diagnosed in the abdomen, often presenting with signs and symptoms of metastatic spread. Three decades ago, high-risk NB metastatic to bone and bone marrow in children was not curable. Today, with multimodality treatment, 50% of these patients will survive, but most suffer from debilitating treatment-related complications. Novel targeted therapies to improve cure rates while minimizing toxicities are urgently needed. Recent molecular discoveries in oncology have spawned the development of an impressive array of targeted therapies for adult cancers, yet the paucity of recurrent somatic mutations or activated oncogenes in pediatric cancers poses a major challenge to the evolving paradigm of personalized medicine. Although low tumor mutational burden is a major hurdle for immune checkpoint inhibitors, an immature or impaired immune system and inhibitory tumor microenvironment can further complicate the prospects for successful immunotherapy. In this regard, despite the poor immunogenic properties of NB, the success of antibody-based immunotherapy and radioimmunotherapy directed at single targets (eg, GD2 and B7-H3) is both encouraging and surprising, given that most solid tumor antibodies that use Fc-dependent mechanisms or radioimmunotargeting have largely failed. Here, we summarize the current information on the immunologic properties of this tumor, its potential immunotherapeutic targets, and novel antibody-based strategies on the horizon.

HMGA2 Gene rs8756 A>C Polymorphism Reduces Neuroblastoma Risk in Chinese Children: A Four-Center Case-Control Study

BACKGROUND

Neuroblastoma, mainly affecting children, is a lethal malignancy arising from the developing sympathetic nervous system. The genetic etiology of neuroblastoma remains mostly obscure. High mobility group AT-hook 2 (HMGA2), an oncogenic gene, is up-regulated in many tumors. Single nucleotide polymorphisms (SNPs) often modify cancer susceptibility. However, no studies are investigating the association between HMGA2 SNPs and neuroblastoma susceptibility.

METHODS

We conducted a four-center case-control study to evaluate the association between three HMGA2 polymorphisms (rs6581658 A>G, rs8756 A>C and rs968697 T>C) and neuroblastoma susceptibility in a Chinese population with 505 cases and 1070 controls. Logistic regression was performed to evaluate the strength of the association.

RESULTS

We found that the rs8756 AC/CC genotypes were associated with a reduced neuroblastoma risk when compared to rs8756 AA genotype [Adjusted odds ratio (OR)=0.74, 95% confidence interval (CI)=0.56-0.99, P=0.039]. Carriers with 3 protective genotypes have lower neuroblastoma susceptibility than those without or with 0-2 protective genotypes. The stratified analysis revealed that the protective effects of rs8756 AC/CC genotypes were more predominant among children of age > 18 months, males, and subgroups with the tumor in the mediastinum. Furthermore, haplotype analysis uncovered that haplotype ACC significantly reduced neuroblastoma risk.

CONCLUSION

Our study indicated HMGA2 rs8756 A>C polymorphism is significantly associated with decreased neuroblastoma risk.

NK cells clear α-synuclein and the depletion of NK cells exacerbates synuclein pathology in a mouse model of α-synucleinopathy

The pathological hallmark of synucleinopathies, including Lewy body dementia and Parkinson's disease (PD), is the presence of Lewy bodies, which are primarily composed of intracellular inclusions of misfolded α-synuclein (α-syn) among other proteins. α-Syn is found in extracellular biological fluids in PD patients and has been implicated in modulating immune responses in the central nervous system (CNS) and the periphery. Natural killer (NK) cells are innate effector lymphocytes that are present in the CNS in homeostatic and pathological conditions. NK cell numbers are increased in the blood of PD patients and their activity is associated with disease severity; however, the role of NK cells in the context of α-synucleinopathies has never been explored. Here, we show that human NK cells can efficiently internalize and degrade α-syn aggregates via the endosomal/lysosomal pathway. We demonstrate that α-syn aggregates attenuate NK cell cytotoxicity in a dose-dependent manner and decrease the release of the proinflammatory cytokine, IFN-γ. To address the role of NK cells in PD pathogenesis, NK cell function was investigated in a preformed fibril α-syn-induced mouse PD model. Our studies demonstrate that in vivo depletion of NK cells in a preclinical mouse PD model resulted in exacerbated motor deficits and increased phosphorylated α-syn deposits. Collectively, our data provide a role of NK cells in modulating synuclein pathology and motor symptoms in a preclinical mouse model of PD, which could be developed into a therapeutic for PD and other synucleinopathies.

The Roles of Alternative Splicing in Tumor-immune Cell Interactions

Alternative splicing (AS) plays a significant role in the hallmarks of cancer and can provide neoantigens for immunotherapy. Here, we summarize recent advances in immune system associated tumor specific-antigens (TSAs) produced by AS. We further discuss the regulating mechanisms involved in AS-mediated innate and adaptive immune responses and the anti-tumoral and protumoral roles in different types of cancer. For example, ULBP1_RI, MLL5Δ21spe, NKp44-1Δ5, MHC-IΔ7, CD200SΔ1, 2, PVR α/β/γ/δ and IL-33 variants 1/2/3 act as regulators in solid tumors and IPAK4-L and, FOXP1ΔN100 exhibit functions in hematological cancers.

Ex Vivo-expanded Natural Killer Cells Derived From Long-term Cryopreserved Cord Blood are Cytotoxic Against Primary Breast Cancer Cells

With over 600,000 units of umbilical cord blood (CB) stored on a global scale, it is important to elucidate the therapeutic abilities of this cryopreserved reservoir. In the advancing field of natural killer (NK) cell cancer immunotherapy, CB has proven to be a promising and noninvasive source of therapeutic NK cells. Although studies have proven the clinical efficacy of using long-term cryopreserved CB in the context of hematopoietic stem cell transplantations, little is known about its use for the ex vivo expansion of effector immune cells. Therefore, our group sought to derive ex vivo-expanded NK cells from long-term cryopreserved CB, using an artificial antigen presenting cell-mediated expansion technique. We compared the expansion potential and antitumor effector function of CB-derived NK (CB-NK) cells expanded from fresh (n=4), short-term cryopreserved (<1-year old, n=5), and long-term cryopreserved (1-10-year old, n=5) CB. Here, we demonstrated it is possible to obtain an exponential amount of expanded CB-NK cells from long-term cryopreserved CB. Ex vivo-expanded CB-NK cells had an increased surface expression of activating markers and showed potent antitumor function by producing robust levels of proinflammatory cytokines, interferon-γ, and tumor necrosis factor-α. Moreover, expanded CB-NK cells (n=3-5) demonstrated cytotoxicity towards primary breast cancer cells (n=2) derived from a triple-negative breast cancer and an estrogen receptor-positive/progesterone receptor-positive breast cancer patient. Long-term cryopreservation had no effect on the expansion potential or effector function of expanded CB-NK cells. Therefore, we propose that long-term cryopreserved CB remains clinically useful for the ex vivo expansion of therapeutic NK cells.

The Role of Natural Killer Cells as a Platform for Immunotherapy in Pediatric Cancers

PURPOSE OF REVIEW

We aim to review the most recent findings in the use of NK cells in childhood cancers.

RECENT FINDINGS

Natural killer cells are cytotoxic to tumor cells. In pediatric leukemias, adoptive transfer of NK cells can bridge children not in remission to transplant. Interleukins (IL2, IL15) can enhance NK cell function. NK cell-CAR therapy has advantages of shorter life span that lessens chronic toxicities, lower risk of graft versus host disease when using allogeneic cells, ability of NK cells to recognize tumor cells that have downregulated MHC to escape T cells, and possibly less likelihood of cytokine storm. Cytotoxicity to solid tumors (rhabdomyosarcoma, Ewing's sarcoma, neuroblastoma) is seen with graft versus tumor effect in transplant and in combination with antibodies. Challenges lie in the microenvironment which is suppressive for NK cells. NK cell immunotherapy in childhood cancers is promising and recent works aim to overcome challenges.

Impact of Tumor and Immunological Heterogeneity on the Anti-Cancer Immune Response

Metastatic tumors are the primary cause of cancer-related mortality. In recent years, interest in the immunologic control of malignancy has helped establish escape from immunosurveillance as a critical requirement for incipient metastases. Our improved understanding of the immune system's interactions with cancer cells has led to major therapeutic advances but has also unraveled a previously unsuspected level of complexity. This review will discuss the vast spatial and functional heterogeneity in the tumor-infiltrating immune system, with particular focus on natural killer (NK) cells, as well as the impact of tumor cell-specific factors, such as secretome composition, receptor-ligand repertoire, and neoantigen diversity, which can further drive immunological heterogeneity. We emphasize how tumor and immunological heterogeneity may undermine the efficacy of T-cell directed immunotherapies and explore the potential of NK cells to be harnessed to circumvent these limitations.

Safety, tolerability, pharmacokinetics, and pharmacodynamics of the afucosylated, humanized anti-EPHA2 antibody DS-8895a: a first-in-human phase I dose escalation and dose expansion study in patients with advanced solid tumors

Background

Erythropoietin-producing hepatocellular receptor A2 (EPHA2) is overexpressed on the cell surface in many cancers and predicts poor prognosis. DS-8895a is a humanized anti-EPHA2 IgG1 monoclonal antibody afucosylated to enhance antibody-dependent cellular cytotoxicity activity. We conducted a two-step, phase I, multicenter, open-label study to determine the safety, tolerability, and pharmacokinetics of DS-8895a in patients with advanced solid tumors.

Methods

Step 1 was a dose escalation cohort in advanced solid tumor patients (six dose levels, 0.1–20 mg/kg) to determine Step 2 dosing. Step 2 was a dose expansion cohort in EPHA2-positive esophageal and gastric cancer patients. DS-8895a was intravenously administered every 2 weeks for the duration of the study, with a 28-day period to assess dose-limiting toxicity (DLT). Safety, pharmacokinetics, tumor response, and potential biomarkers were evaluated.

Results

Thirty-seven patients (Step 1: 22, Step 2: 15 [9: gastric cancer, 6: esophageal cancer]) were enrolled. Although one DLT (Grade 4 platelet count decreased) was observed in Step 1 (dose level 6, 20 mg/kg), the maximum tolerated dose was not reached; the highest dose (20 mg/kg) was used in Step 2. Of the 37 patients, 24 (64.9%) experienced drug-related adverse events (AEs) including three (8.1%) with Grade ≥ 3 AEs. Infusion-related reactions occurred in 19 patients (51.4%) but were manageable. All patients discontinued the study (evident disease progression, 33; AEs, 4). Maximum and trough serum DS-8895a concentrations increased dose-dependently. One gastric cancer patient achieved partial response and 13 patients achieved stable disease. Serum inflammatory cytokines transiently increased at completion of and 4 h after the start of DS-8895a administration. The proportion of CD16-positive natural killer (NK) cells (CD3⁻CD56⁺CD16⁺) decreased 4 h after the start of DS-8895a administration, and the ratio of CD3⁻CD56⁺CD137⁺ to CD3⁻CD56⁺CD16⁺ cells increased on day 3.

Conclusions

Twenty mg/kg DS-8895a infused intravenously every 2 weeks was generally safe and well tolerated in patients (n = 21) with advanced solid tumors. The exposure of DS-8895a seemed to increase dose-dependently and induce activated NK cells.

Trial registration

Phase 1 Study of DS-8895a in patients with advanced solid tumors (NCT02004717; 7 November 2013 to 2 February 2017); retrospectively registered on 9 December 2013.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0679-9) contains supplementary material, which is available to authorized users.

Preparation of highly activated natural killer cells for advanced lung cancer therapy

Background: Natural killer (NK) cells can be used as an adoptive immunotherapy to treat cancer patients. Purpose: In this study, we evaluated the efficacy of highly activated NK (HANK) cell immunotherapy in patients with advanced lung cancer. Patients and methods: Between March 2016 and September 2017, we enrolled 13 patients who met the enrollment criteria. Donor peripheral blood monocytes were isolated from patients and the NK cells were expanded. After 12 days of culture, the cells were collected and infused intravenously on days 13 to 15. The enrolled patients received at least one course including three times of infusions. The lymphocyte subsets, cytokine production, and the expression of carcinoembryonic antigen (CEA) and thymidine kinase 1 (TK1) were measured before treatment and after the last infusion. Results: No side effects were observed. After a three-month follow-up, the percentage of patients who achieved stable disease and progressive disease was 84.6% and 15.4%. Moreover, the level of IFN-γ was significantly higher after treatment and the level of CEA decreased substantially. The overall immune function of the patients who received the NK cell therapy remained stable. Conclusion: This is the first study to describe the efficacy of NK cell therapy of patients with advanced lung cancer. These clinical observations demonstrated that NK cell is safe and efficient for advanced lung cancer therapy.

Stage IV Neuroblastoma with Metastatic Spread to the Mandible in a Young Child: Case Report and Review of the Literature

BACKGROUND

Infants and young children with neuroblastoma (NB) may present with metastases. The primary tumor most commonly originates in the abdomen and metastasizes to lymph nodes, liver, and bone marrow. Infants and young children presenting with multiple skull metastases are rare.

METHODS

We present a rare case of a 20-month-old child who presented with metastatic neuroblastoma and multiple skull lesions. The child responded well to induction chemotherapy followed by myeloablative busulfan/melphalan consolidation.

RESULTS

The child had substantial tumor reduction after chemotherapy was started. There was a significant decrease in tumor sizes and uptake, as seen in the metaiodobenzylguanidine study. The 6-month follow-up examination showed complete remission, and the remission continues.

CONCLUSIONS

Infants and young children with neuroblastoma rarely present with metastatic lesions to the skull. Even large lesions involving the skull base may be successfully treated with chemotherapy. The use of myeloablative busulfan/melphalan consolidation after induction chemotherapy can decrease the overall metastatic tumor burden. Craniofacial specialists should be aware of treatment options for these young children.

Feasibility and Safety of Treosulfan, Melphalan, and Thiotepa-Based Megachemotherapy with Autologous or Allogeneic Stem Cell Transplantation in Heavily Pretreated Children with Relapsed or Refractory Neuroblastoma

The prognosis of resistant or relapsing children with neuroblastoma remains very poor, and the search for new therapies is ongoing. In this analysis, we assessed the toxicity of a treosulfan, melphalan, and thiotepa (TMT) regimen in 17 children with recurrent or refractory neuroblastoma who underwent stem cell transplantation (SCT). For allogeneic SCT, fludarabine and antithymocyte globulin were added. The stem cell source was autologous in 8 patients, haploidentical in 8 patients, and a matched unrelated donor in 1 patient. The reported nonhematologic toxicities included grade 3 mucositis, grade 1 to 3 hypertransaminasemia, and in 3 patients, veno-occlusive disease. No neurologic, cardiac, or dermatologic toxicities were observed. The probability of overall survival (OS) in patients with primary resistance was superior to that in patients with relapsed disease (100% versus 22.6%; P = .046). Post-transplantation dinutuximab beta immunotherapy was associated with superior 5-year OS (66.7% versus 11.4%; P = .0007). The use of an allogeneic donor, previous autologous SCT with busulfan and melphalan, and pretreatment with high-dose metaiodobenzylguanidine therapy demonstrated no effect on outcomes. In 4 patients, TMT megatherapy alone was enough to achieve complete remission. The TMT conditioning regimen was well tolerated in heavily pretreated patients with neuroblastoma. The manageable toxicity and addition of new anticancer drugs with optional post-SCT immunotherapy or chemotherapy support further trials with the TMT regimen in patients with neuroblastoma.

Follicular lymphoma patients with KIR2DL2 and KIR3DL1 and their ligands (HLA-C1 and HLA-Bw4) show improved outcome when receiving rituximab

BACKGROUND

The ECOG-ACRIN Cancer Research Group evaluated rituximab treatment schedules for patients with newly-diagnosed low-tumor-burden follicular-lymphoma (FL). All patients received 4-weekly rituximab treatments as induction therapy. Clinically-responding patients were randomized to receive rituximab every 13 weeks ("maintenance") vs. no additional rituximab until progression ("non-maintenance"). Based on "time-to-rituximab-failure (TTRF)", the study-committee reported there was no overall-benefit for maintenance rituximab in this setting. Tumor-reactive mAbs, like rituximab, trigger natural killer (NK) cells. NK-cell responses are regulated, in part, by interactions between killer immunoglobulin-like receptors (KIRs) on NK cells and their interactions with KIR-ligands. In a separate study of children with neuroblastoma treated with a different mAb, we found certain KIR/KIR-ligand genotypes associated with improved outcome. Here, we assessed whether a subset of FL patients show improved outcome from the maintenance rituximab based on these same KIR/KIR-ligand genotypes.

METHODS

Genotypes for KIR/KIR-ligand were determined and assessed for associations with outcome [duration of response, TTRF and % tumor shrinkage] as a post-hoc analysis of this phase III trial. Our primary objective was to assess specific KIR/KIR-ligand genotype associations, followed by separate prespecified KIR/KIR-ligand genotype associations in follow-up analyses. Statistical analyses for association of genotype with clinical outcome included: Log-rank tests and Cox proportional hazards regression models to assess duration of response and TTRF; analysis of variance (ANOVA) was used for assessment of % tumor shrinkage.

RESULTS

We found that patients inheriting KIR2DL2 and its ligand (HLA-C1) along with KIR3DL1 and its ligand (HLA-Bw4) had improved outcome over patients without this genotype. In addition, patients with KIR2DL2 and HLA-C1 along with KIR3DL1 and HLA-Bw4 also showed improved duration of response and tumor shrinkage if they received maintenance, while patients without this genotype showed no such improvement when receiving maintenance.

CONCLUSIONS

The data presented here indicate that a subset of FL patients, identified by certain KIRs/KIR-ligands, have improved outcome and may benefit from additional rituximab treatment. Taken together, this suggests that the efficacy of tumor-reactive mAb treatment for some patients is influenced by KIRs on NK cells. However, prior to considering these genotypes in a clinically-actionable manner, these findings need independent validation in other studies.

Spotlight on dinutuximab in the treatment of high-risk neuroblastoma: development and place in therapy

Neuroblastoma (NB) is a pediatric cancer of the sympathetic nervous system which accounts for 8% of childhood cancers. Most NBs express high levels of the disialoganglioside GD2. Several antibodies have been developed to target GD2 on NB, including the human/mouse chimeric antibody ch14.18, known as dinutuximab. Dinutuximab used in combination with granulocyte-macrophage colony-stimulating factor, interleukin-2, and isotretinoin (13-cis-retinoic acid) has a US Food and Drug Administration (FDA)-registered indication for treating high-risk NB patients who achieved at least a partial response to prior first-line multi-agent, multimodality therapy. The FDA registration resulted from a prospective randomized trial assessing the benefit of adding dinutuximab + cytokines to post-myeloablative maintenance therapy for high-risk NB. Dinutuximab has also shown promising antitumor activity when combined with temozolomide and irinotecan in treating NB progressive disease. Clinical activity of dinutuximab and other GD2-targeted therapies relies on the presence of the GD2 antigen on NB cells. Some NBs have been reported as GD2 low or negative, and such tumor cells could be nonresponsive to anti-GD2 therapy. As dinutuximab relies on complement and effector cells to mediate NB killing, factors affecting those components of patient response may also decrease dinutuximab effectiveness. This review summarizes the development of GD2 antibody-targeted therapy, the use of dinutuximab in both up-front and salvage therapy for high-risk NB, and the potential mechanisms of resistance to dinutuximab.

Anti-cancer Therapies Employing IL-2 Cytokine Tumor Targeting: Contribution of Innate, Adaptive and Immunosuppressive Cells in the Anti-tumor Efficacy

Antibody-cytokine fusion proteins (immunocytokine) exert a potent anti-cancer effect; indeed, they target the immunosuppressive tumor microenvironment (TME) due to a specific anti-tumor antibody linked to immune activating cytokines. Once bound to the target tumor, the interleukin-2 (IL-2) immunocytokines composed of either full antibody or single chain Fv conjugated to IL-2 can promote the in situ recruitment and activation of natural killer (NK) cells and cytotoxic CD8+ T lymphocytes (CTL). This recruitment induces a TME switch toward a classical T helper 1 (Th1) anti-tumor immune response, supported by the cross-talk between NK and dendritic cells (DC). Furthermore, some IL-2 immunocytokines have been largely shown to trigger tumor cell killing by antibody dependent cellular cytotoxicity (ADCC), through Fcγ receptors engagement. The modulation of the TME can be also achieved with immunocytokines conjugated with a mutated form of IL-2 that impairs regulatory T (Treg) cell proliferation and activity. Preclinical animal models and more recently phase I/II clinical trials have shown that IL-2 immunocytokines can avoid the severe toxicities of the systemic administration of high doses of soluble IL-2 maintaining the potent anti-tumor effect of this cytokine. Also, very promising results have been reported using IL-2 immunocytokines delivered in combination with other immunocytokines, chemo-, radio-, anti-angiogenic therapies, and blockade of immune checkpoints. Here, we summarize and discuss the most relevant reported studies with a focus on: (a) the effects of IL-2 immunocytokines on innate and adaptive anti-tumor immune cell responses as well as immunosuppressive Treg cells and (b) the approaches to circumvent IL-2-mediated severe toxic side effects.

Novel Therapies for Relapsed and Refractory Neuroblastoma

While recent increases in our understanding of the biology of neuroblastoma have allowed for more precise risk stratification and improved outcomes for many patients, children with high-risk neuroblastoma continue to suffer from frequent disease relapse, and despite recent advances in our understanding of neuroblastoma pathogenesis, the outcomes for children with relapsed neuroblastoma remain poor. These children with relapsed neuroblastoma, therefore, continue to need novel treatment strategies based on a better understanding of neuroblastoma biology to improve outcomes. The discovery of new tumor targets and the development of novel antibody- and cell-mediated immunotherapy agents have led to a large number of clinical trials for children with relapsed neuroblastoma, and additional clinical trials using molecular and genetic tumor profiling to target tumor-specific aberrations are ongoing. Combinations of these new therapeutic modalities with current treatment regimens will likely be needed to improve the outcomes of children with relapsed and refractory neuroblastoma.

Killer immunoglobulin-like receptor genotype did not correlate with response to anti-PD-1 antibody treatment in a Japanese cohort

Immune checkpoint blockade (ICB) induces a remarkable response in patients with certain cancers. However, the response rate is not yet satisfactory. Biomarkers that help physicians identify patients who would benefit from ICB need to be developed. Killer immunoglobulin-like receptors (KIRs) are a class of receptors that are mainly expressed by natural killer cells. KIR genotypes have been shown to influence the outcomes of patients with neuroblastoma and hematopoietic malignancies. KIRs may thus influence the clinical outcomes of melanoma patients receiving nivolumab. We aimed to identify the KIR genotype, or KIR/KIR-ligand combinations, which influence the outcomes of melanoma patients receiving nivolumab. We genotyped 112 melanoma patients who were treated with nivolumab for KIR and human leukocyte antigen. The clinical records of the patients were analyzed to determine if they showed a response to nivolumab, and whether or not they experienced adverse events. Our analysis showed that no KIR gene was associated with a response to nivolumab. The KIR/KIR-ligand combination did not correlate with a response to nivolumab. KIR genes were not predictive of experiencing adverse events of grade 2 or greater. We conclude that the KIR genotype or KIR/KIR-ligand genotype do not show predictive value in melanoma patients receiving nivolumab.

Iodine-125 seed implantation and allogenic natural killer cell immunotherapy for hepatocellular carcinoma after liver transplantation: a case report

For advanced hepatocellular carcinoma (HCC) patients, liver transplantation (LT) is an optimal treatment with limitation of high risk of tumor recurrence related to the immunosuppressive chemotherapy as usually recommended. In this study, a 29-year-old man suffered from HCC recurrence after LT. He underwent radiotherapy (total dose: 45 Gy) but had no significant response. Then, he received iodine-125 seed implantation combined with allogenic natural killer (NK) cell immunotherapy. Liver function, immune function, circulating tumor cell counts and computed tomography scans were evaluated to determine the clinical effect. We found that this combined treatment produced enhanced immune function of the patient and reduction in tumor size. This is the first report of an efficacy and safety study about clinical regimen comprising allogenic NK cell immunotherapy combined with iodine-125 seed implantation for the treatment of HCC recurrence after LT.

CAR T Cell Therapy for Neuroblastoma

Patients with high risk neuroblastoma have a poor prognosis and survivors are often left with debilitating long term sequelae from treatment. Even after integration of anti-GD2 monoclonal antibody therapy into standard, upftont protocols, 5-year overall survival rates are only about 50%. The success of anti-GD2 therapy has proven that immunotherapy can be effective in neuroblastoma. Adoptive transfer of chimeric antigen receptor (CAR) T cells has the potential to build on this success. In early phase clinical trials, CAR T cell therapy for neuroblastoma has proven safe and feasible, but significant barriers to efficacy remain. These include lack of T cell persistence and potency, difficulty in target identification, and an immunosuppressive tumor microenvironment. With recent advances in CAR T cell engineering, many of these issues are being addressed in the laboratory. In this review, we summarize the clinical trials that have been completed or are underway for CAR T cell therapy in neuroblastoma, discuss the conclusions and open questions derived from these trials, and consider potential strategies to improve CAR T cell therapy for patients with neuroblastoma.

Diversification of Bw4 Specificity and Recognition of a Nonclassical MHC Class I Molecule Implicated in Maternal-Fetal Tolerance by Killer Cell Ig-like Receptors of the Rhesus Macaque

The rhesus macaque is an important animal model for AIDS and other infectious diseases; however, studies to address NK cell function in this species have been limited by the lack of defined ligands for killer cell Ig-like receptors (KIRs). To identify ligands for rhesus macaque KIRs, we adopted a novel approach based on a pair of stable cell lines. NFAT-responsive luciferase reporter cell lines expressing the extracellular domains of macaque KIRs fused to the transmembrane and cytoplasmic domains of CD28 and CD3ζ were incubated with target cells expressing individual MHC class I molecules, and ligand recognition was detected by the MHC class I-dependent upregulation of luciferase. Using this approach, we found that Mamu-KIR3DL01, -KIR3DL06, -KIR3DL08, and -KIR3DSw08 all recognize Mamu-Bw4 molecules but with differing allotype specificity. In contrast, Mamu-KIR3DL05 recognizes Mamu-A and Mamu-A-related molecules, including Mamu-A1*002 and -A3*13, Mamu-B*036, the product of a recombinant Mamu-B allele with α1 and α2 domain sequences derived from a MHC-A gene, and Mamu-AG*01, a nonclassical molecule expressed on placental trophoblasts that originated from an ancestral duplication of a MHC-A gene. These results reveal an expansion of the lineage II KIRs in macaques that recognize Bw4 ligands and identify a nonclassical molecule implicated in placental development and pregnancy as a ligand for Mamu-KIR3DL05. In addition to offering new insights into KIR-MHC class I coevolution, these findings provide an important foundation for investigating the role of NK cells in the rhesus macaque as an animal model for infectious diseases and reproductive biology.

Altered NKp30, NKp46, NKG2D, and DNAM-1 Expression on Circulating NK Cells Is Associated with Tumor Progression in Human Gastric Cancer

Natural killer (NK) cell activity is influenced by a complex integration of signaling pathways activated downstream of both activating and inhibitory surface receptors. The tumor microenvironment can suppress NK cell activity, and there is a great clinical interest in understanding whether modulating tumor-mediated NK cell suppression and/or boosting preexisting NK cell numbers in cancer patients is therapeutically viable. To this light, we characterized the surface receptor phenotypes of peripheral blood NK cells and examined their clinical relevance to human gastric cancer (GC). We found that the proportion of peripheral blood NK cells which expressed the activating receptors NKp30, NKp46, NKG2D, and DNAM-1 was significantly decreased in GC patients compared to healthy donors, and that this decrease was positively associated with tumor progression. At the same time, plasma TGF-β1 concentrations were significantly increased in GC patients and negatively correlated with the proportion of NKp30, NKp46, NKG2D, and DNAM-1 expressing NK cells. Furthermore, TGF-β1 significantly downregulated the expression of NKp30, NKp46, NKG2D, and DNAM-1 on NK cells in vitro, and the addition of galunisertib, an inhibitor of the TGF-β receptor subunit I, reversed this downregulation. Altogether, our data suggest that the decreased expression of activating receptors NKp30, NKp46, NKG2D, and DNAM-1 on peripheral blood NK cells is positively associated with GC progression, and that TGF-β1-mediated NK cell suppression may be a therapeutically targetable characteristic of GC.

Expression of Disialoganglioside (GD2) in Neuroblastic Tumors: A Prognostic Value for Patients Treated With Anti-GD2 Immunotherapy

Neuroblastoma, a malignant neoplasm of the sympathetic nervous system, is one of the most aggressive pediatric cancers. Patients with stage IV high-risk neuroblastoma receive an intensive multimodal therapy ending with an immunotherapy based on a chimeric monoclonal antibody ch14.18. Although the use of ch14.18 monoclonal antibody has significantly increased the survival rate of high-risk neuroblastoma patients, about 33% of these patients still relapse and die from their disease. Ch14.18 targets the disialoganglioside, GD2, expressed on neuroblastic tumor (NT) cells. To better understand the causes of tumor relapse following ch14.18 immunotherapy, we have analyzed the expression of GD2 in 152 tumor samples from patients with NTs using immunohistochemical stainings. We observed GD2 expression in 146 of 152 samples (96%); however, the proportion of GD2-positive cells varied among samples. Interestingly, low percentage of GD2-positive cells before immunotherapy was associated with relapse in patients receiving ch14.18 immunotherapy. In addition, we demonstrated in vitro that the sensitivity of neuroblastoma cell lines to natural killer-mediated lysis was dependent on the proportion of GD2-positive cells, in the presence of ch14.18 antibody. In conclusion, our results indicate that the proportion of tumor cells expressing GD2 in NTs should be taken in consideration, as a prognostic marker, for high-risk neuroblastoma patients receiving anti-GD2 immunotherapy.