IL-10 and ARG-1 concentrations in bone marrow and peripheral blood of metastatic neuroblastoma patients do not associate with clinical outcome

A biomaterial-based therapy for lower limb ischemia using Sr/Si bioactive hydrogel that inhibits skeletal muscle necrosis and enhances angiogenesis

Muscle necrosis and angiogenesis are two major challenges in the treatment of lower-limb ischemic diseases. In this study, a triple-functional Sr/Si-containing bioceramic/alginate composite hydrogel with simultaneous bioactivity in enhancing angiogenesis, regulating inflammation, and inhibiting muscle necrosis was designed to treat lower-limb ischemic diseases. In particular, sodium alginate, calcium silicate and strontium carbonate were used to prepare injectable hydrogels, which was gelled within 10 min. More importantly, this composite hydrogel sustainedly releases bioactive Sr²⁺ and SiO₃ ^2- ions within 28 days. The biological activity of the bioactive ions released from the hydrogels was verified on HUVECs, SMCs, C2C12 and Raw 264.7 cells in vitro, and the therapeutic effect of the hydrogel was confirmed using C57BL/6 mouse model of femoral artery ligation in vivo. The results showed that the composite hydrogel stimulated angiogenesis, developed new collateral capillaries, and re-established the blood supply. In addition, the bioactive hydrogel directly promoted the expression of muscle-regulating factors (MyoG and MyoD) to protect skeletal muscle from necrosis, inhibited M1 polarization, and promoted M2 polarization of macrophages to reduce inflammation, thereby protecting skeletal muscle cells and indirectly promoting vascularization. Our results indicate that these bioceramic/alginate composite bioactive hydrogels are effective biomaterials for treating hindlimb ischemia and suggest that biomaterial-based approaches may have remarkable potential in treating ischemic diseases.

Bone Marrow Environment in Metastatic Neuroblastoma

The study of the interactions occurring in the BM environment has been facilitated by the peculiar nature of metastatic NB. In fact: (i) metastases are present at diagnosis; (ii) metastases are confined in a very specific tissue, the BM, suggestive of a strong attraction and possibility of survival; (iii) differently from adult cancers, NB metastases are available because the diagnostic procedures require morphological examination of BM; (iv) NB metastatic cells express surface antigens that allow enrichment of NB metastatic cells by immune-magnetic separation; and (v) patients with localized disease represent an internal control to discriminate specific alterations occurring in the metastatic niche from generic alterations determined by the neoplastic growth at the primary site. Here, we first review the information regarding the features of BM-infiltrating NB cells. Then, we focus on the alterations found in the BM of children with metastatic NB as compared to healthy children and children with localized NB. Specifically, information regarding all the BM cell populations and their sub-sets will be first examined in the context of BM microenvironment in metastatic NB. In the last part, the information regarding the soluble factors will be presented.

Tumor-tagging by oncolytic viruses: A novel strategy for CAR-T therapy against solid tumors

Chimeric antigen receptor (CAR) T cell therapy is one of the most promising immunotherapies in the past decade. It brings hope for cure to patients with previously refractory hematological malignancies. However, when translating this strategy into non-hematologic malignancies, the antitumor activity from multiple clinical studies seemed to be subtle or transient. The less satisfying efficacy in solid tumors might at least due to antigen heterogeneity, suboptimal CAR-T cell trafficking and tumor immunosuppressive environment. Here, we will review the updating strategies to challenge the therapeutic impediments of CAR-T therapy in non-hematologic malignancies. We mainly focus on the combination with oncolytic viruses (OV), the born allies for CAR-T cells. In addition to previously reported OVs-arming strategy, we discuss recently proposed tumor-tagging concept by OVs as CAR-T targets, as well as the possible improvements. Overall, tumor-tagging strategy by OVs combination with CAR-T would be a novel and promising solution for the heterogeneity and immunosuppressive microenvironment of solid tumors.

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.

Up-regulation of MiR-145-5p promotes the growth and migration in LPS-treated HUVECs through inducing macrophage polarization to M2

MiR-145-5p is high-expressed in human vascular endothelial cells (HUVECs) and alternatively activated macrophages (M2). However, whether miR-145-5p can reduce HUVEC damage by regulating macrophage immunophenotype is less reported. THP-1 was stimulated by Phorbolate-12-myristate-13-acetate, LPS and IFN-γ, and IL-4 to differentiate into macrophages (M0, M1 and M2). The expressions of macrophage markers were detected by Western blotting, and the expressions of miR-145-5p and kruppel-like factor-14 (KLF14) were detected by qRT-PCR. Dual-luciferase reporter assay was used to analyze the targeted relationship of miR-145-5p and KLF14. HUVEC injury was induced by LPS and then co-cultured with M1 transfected by miR-145-5p mimic. The effect of miR-145-3p on proliferation and metastasis of LPS-induced HUVECs was detected by MTT, clone formation, scratch assay and Transwell. We found that the expression of miR-145-5p was higher in M2 than that in M1. MiR-145-5p expression was down-regulated during M2-to-M1, but up-regulated during M1-to-M2. The expressions of IL-1β and iNOS were down-regulated, while the protein expressions of CCL17 and Arg-1 were up-regulated by miR-145-5p mimic in M0. The viability, proliferation, migration and invasion of HUVECs were promoted, however, LDH activity of the HUVECs was inhibited by mimics. In addition, KLF14 was predicted as the target gene for miR-145-5p in HUVECs. Collectively, our results demonstrate that miR-145-5p inhibited cell proliferation of LPS-treated HUVECs possibly through regulating macrophage polarization to M2.

"Re-educating" Tumor Associated Macrophages as a Novel Immunotherapy Strategy for Neuroblastoma

Neuroblastoma is the most common extracranial pediatric tumor and often presents with metastatic disease, and patients with high-risk neuroblastoma have survival rates of ~50%. Neuroblastoma tumorigenesis is associated with the infiltration of various types of immune cells, including myeloid derived suppressor cells, tumor associated macrophages (TAMs), and regulatory T cells, which foster tumor growth and harbor immunosuppressive functions. In particular, TAMs predict poor clinical outcomes in neuroblastoma, and among these immune cells, TAMs with an M2 phenotype comprise an immune cell population that promotes tumor metastasis, contributes to immunosuppression, and leads to failure of radiation or checkpoint inhibitor therapy. This review article summarizes the role of macrophages in tumor angiogenesis, metastasis, and immunosuppression in neuroblastoma and discusses the recent advances in "macrophage-targeting strategies" in neuroblastoma with a focus on three aspects: (1) inhibition of macrophage recruitment, (2) targeting macrophage survival, and (3) reprogramming of macrophages into an immunostimulatory phenotype.

Targeting the Tumor Microenvironment in Neuroblastoma: Recent Advances and Future Directions

Neuroblastoma (NB) is the most common pediatric tumor malignancy that originates from the neural crest and accounts for more than 15% of all the childhood deaths from cancer. The neuroblastoma cancer research has long been focused on the role of MYCN oncogene amplification and the contribution of other genetic alterations in the progression of this malignancy. However, it is now widely accepted that, not only tumor cells, but the components of tumor microenvironment (TME), including extracellular matrix, stromal cells and immune cells, also contribute to tumor progression in neuroblastoma. The complexity of different components of tumor stroma and their resemblance with surrounding normal tissues pose huge challenges for therapies targeting tumor microenvironment in NB. Hence, the detailed understanding of the composition of the TME of NB is crucial to improve existing and future potential immunotherapeutic approaches against this childhood cancer. In this review article, I will discuss different components of the TME of NB and the recent advances in the strategies, which are used to target the tumor microenvironment in neuroblastoma.

Monitoring Immune Responses in Neuroblastoma Patients during Therapy

Neuroblastoma (NBL) is the most common extracranial solid tumor in childhood. Despite intense treatment, children with this high-risk disease have a poor prognosis. Immunotherapy showed a significant improvement in event-free survival in high-risk NBL patients receiving chimeric anti-GD2 in combination with cytokines and isotretinoin after myeloablative consolidation therapy. However, response to immunotherapy varies widely, and often therapy is stopped due to severe toxicities. Objective markers that help to predict which patients will respond or develop toxicity to a certain treatment are lacking. Immunotherapy guided via immune monitoring protocols will help to identify responders as early as possible, to decipher the immune response at play, and to adjust or develop new treatment strategies. In this review, we summarize recent studies investigating frequency and phenotype of immune cells in NBL patients prior and during current treatment protocols and highlight how these findings are related to clinical outcome. In addition, we discuss potential targets to improve immunogenicity and strategies that may help to improve therapy efficacy. We conclude that immune monitoring during therapy of NBL patients is essential to identify predictive biomarkers to guide patients towards effective treatment, with limited toxicities and optimal quality of life.

Secretory High-Mobility Group Box 1 Protein Affects Regulatory T Cell Differentiation in Neuroblastoma Microenvironment In Vitro

Neuroblastoma (NB) is the most common extracranial tumor of childhood with poor prognosis in a high-risk group. An obstacle in the development of treatment for solid tumors is the immunosuppressive nature of the tumor microenvironment (TME). Regulatory T cells (Tregs) represent a T cell subset with specialized function in immune suppression and maintaining self-tolerance. Tregs resident within the tumor milieu is believed to play an important role in immune escape mechanisms. The role of the NB microenvironment in promoting Treg phenotype has never been elucidated. Herein, we demonstrated that the NB microenvironment promoted T cell activation and one NB cell line, SK-N-SH, manifested an ability to induce Treg differentiation. We identified tumor-derived HMGB1 as a potential protein responsible for Treg phenotype induction. By neutralizing HMGB1, Treg differentiation was abolished. Finally, we adopted a dataset of 498 pediatric NB via the NCBI GEO database, accession GSE49711, to validate clinical relevance of HMGB1 overexpression. Up to 11% of patients had HMGB1-overexpressed tumors. Moreover, this patient subpopulation showed higher risks of tumor progression, relapse, or death. Our findings emphasize the importance of immunological signature of tumor cells for appropriate therapeutic approach. Upregulation of secretory HMGB1 may contribute to suppression of antitumor immunity through induction of Tregs in the NB microenvironment.

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.

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.

Immune Escape Mechanisms and Future Prospects for Immunotherapy in Neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood with 5-year survival rate of 40% in high-risk patients despite intensive therapies. Recently, adoptive cell therapy, particularly chimeric antigen receptor (CAR) T cell therapy, represents a revolutionary treatment for hematological malignancies. However, there are challenges for this therapeutic strategy with solid tumors, as a result of the immunosuppressive nature of the tumor microenvironment (TME). Cancer cells have evolved multiple mechanisms to escape immune recognition or to modulate immune cell function. Several subtypes of immune cells that infiltrate tumors can foster tumor development, harbor immunosuppressive activity, and decrease an efficacy of adoptive cell therapies. Therefore, an understanding of the dual role of the immune system under the influences of the TME has been crucial for the development of effective therapeutic strategies against solid cancers. This review aims to depict key immune players and cellular pathways involved in the dynamic interplay between the TME and the immune system and also to address challenges and prospective development of adoptive T cell transfer for neuroblastoma.

Combined immunotherapy with anti-PDL-1/PD-1 and anti-CD4 antibodies cures syngeneic disseminated neuroblastoma

Anti-PD-1 or anti-PD-L1 blocking monoclonal antibodies (mAbs) have shown potent anti-tumor effects in adult cancer patients and clinical studies have recently been started in pediatric cancers, including high-risk/relapsing neuroblastoma (NB). Therefore, we studied the effects of anti-PD-1/PD-L1 mAbs in two syngeneic models of disseminated NB generated by the injection of either Neuro2a or NXS2 cells, which express PD-L1. In addition, we tested the combination of these agents with the immune-enhancing cytokine IL-21, the Ecto-NTPDase inhibitor POM-1, an anti-CD25 mAb targeting Treg cells, or an anti-CD4 mAb. We previously showed that CD4-transient depletion removes CD4⁺CD25⁺ Treg cells and other CD4⁺CD25⁻ regulatory subsets. Here we show that mono-therapy with anti-PD-1/PD-L1 mAbs had no effect on systemic NB progression in vivo, and also their combination with IL-21, POM-1 or anti-CD25 mAb was ineffective. The combined use of anti-PD-1 with an anti-CD4 mAb mediated a very potent, CD8-dependent, synergistic effect leading to significant elongation of tumor-free survival of mice, complete tumor regression and durable anti-NB immunity. Similar results were obtained by combining the anti-PD-L1 and anti-CD4 mAbs. These findings indicate that both PD-1/PD-L1 and CD4⁺ T cell-related immune-regulatory mechanisms must be simultaneously blocked to mediate therapeutic effects in these models.

Neuroblastoma causes alterations of the intestinal microbiome, gut hormones, inflammatory cytokines, and bile acid composition

OBJECTIVE

To assess the effect of neuroblastoma (NB) on the intestinal microbiome, metabolism, and inflammatory parameters in a murine model.

MATERIALS AND METHODS

Athymic Hsd:Fox1nu mice received subperitoneal implantation of human NB cells (MHH-NB11) (tumor group, TG) or culture medium (sham group). Following 10 weeks of tumor growth, all animals were sacrificed to collect total white adipose tissue (WAT). Luminex assays were performed for gut hormone and inflammation marker analysis. Bile acids were measured by high-performance liquid chromatography-mass spectrometry in feces and serum. The microbiome of the ileal content was determined by 16S rDNA next-generation sequencing.

RESULTS

At 10 weeks, tumors masses in the TG reached a mean weight of 1.10 g (interquartile range 3.45 g) associated with a significant reduction in WAT. Furthermore, in the TG, there was a marked reduction in leptin and an increase in glucagon-like peptide 1 serum levels. Moreover, the TG mice displayed a pro-inflammatory profile, with significant increases in monocyte chemotactic protein 1, tumor necrosis factor alpha, and interleukin-10. Lithocholic acid, deoxycholic acid, and ursodeoxycholic acid were significantly decreased in the stool of TG mice. Significant alterations of the intestinal microbiome were found in the ileal contents of the TG.

CONCLUSIONS

The present study provides a first glimpse that human NB in a murine model induces tumor cachexia associated with alterations in metabolic and inflammatory parameters, as well as changes in the intestinal microbiota. Since the intestinal microbiome is known to contribute to the host's ability to harvest energy, a favorable modulation of the intestinal microbiome in tumor patients could potentially represent a novel therapeutic target to prevent tumor-associated cachexia.

CD4+CD25hiCD127- Treg and CD4+CD45R0+CD49b+LAG3+ Tr1 cells in bone marrow and peripheral blood samples from children with neuroblastoma

Metastatic spread in the bone marrow (BM) at diagnosis is the worst prognostic factor for neuroblastoma (NB) patients. Here, we analyzed the presence of two immunosuppressive cell subsets, CD4⁺CD25^hiCD127^- regulatory T (Treg) cells and CD4⁺CD45R0⁺CD49b⁺LAG3⁺ type 1 regulatory (Tr1) cells, in BM and peripheral blood (PB) samples from NB patients and controls. Frequency of both regulatory cell subsets was lower in BM and PB samples from NB patients than in respective healthy controls. No correlation was found between the frequency of Treg and Tr1 cells and prognostic factors at diagnosis, such as age and stage. Only MYCN amplification correlated to a higher number of Treg in BM and of Tr1 in PB. These findings suggested an altered trafficking of regulatory T cells in NB, but delineated a limited role of these subsets in BM microenvironment and/or periphery in NB. These observations should be considered designing immunotherapeutic approaches for metastatic NB.