Immune checkpoint molecules in neuroblastoma: A clinical perspective

The neuroblastoma tumor microenvironment: From an in-depth characterization towards novel therapies

Neuroblastoma is a cancer of the sympathetic nervous system that develops in young children, either as low-risk or high-risk disease. The tumor microenvironment (TME) is now recognized as an important player of the tumor ecosystem that may promote drug resistance and immune escape. Targeting the TME in combination with therapies directly targeting tumor cells therefore represents an interesting strategy to prevent the emergence of resistance in cancer and improve patient's outcome. The development of such strategies however requires an in-depth understanding of the TME landscape, due to its high complexity and intra and inter-tumoral heterogeneity. Various approaches have been used in the last years to characterize the immune and non-immune cell populations present in tumors of neuroblastoma patients, both quantitatively and qualitatively, in particular with the use of single-cell transcriptomics. It is anticipated that in the near future, both genomic and TME information in tumors will contribute to a precise approach to therapy in neuroblastoma. Deciphering the mechanisms of interaction between neuroblastoma cells and stromal or immune cells in the TME is key to identify novel therapeutic combinations. Over the last decade, numerous in vitro studies and in vivo pre-clinical experiments in immune-competent and immune-deficient models have identified therapeutic approaches to circumvent drug resistance and immune escape. Some of these studies have formed the basis for early phase I and II clinical trials in children with recurrent and refractory high-risk neuroblastoma. This review summarizes recently published data on the characterization of the TME landscape in neuroblastoma and novel strategies targeting various TME cellular components, molecules and pathways activated as a result of the tumor-host interactions.

Review of Patient Gene Profiles Obtained through a Non-Negative Matrix Factorization-Based Framework to Determine the Role Inflammation Plays in Neuroblastoma Pathogenesis

Neuroblastoma is the most common extracranial solid tumor in children. It is a highly heterogeneous tumor consisting of different subcellular types and genetic abnormalities. Literature data confirm the biological and clinical complexity of this cancer, which requires a wider availability of gene targets for the implementation of personalized therapy. This paper presents a study of neuroblastoma samples from primary tumors of untreated patients. The focus of this analysis is to evaluate the impact that the inflammatory process may have on the pathogenesis of neuroblastoma. Eighty-eight gene profiles were selected and analyzed using a non-negative matrix factorization framework to extract a subset of genes relevant to the identification of an inflammatory phenotype, whose targets (PIK3CG, NFATC2, PIK3R2, VAV1, RAC2, COL6A2, COL6A3, COL12A1, COL14A1, ITGAL, ITGB7, FOS, PTGS2, PTPRC, ITPR3) allow further investigation. Based on the genetic signals automatically derived from the data used, neuroblastoma could be classified according to stage rather than as a "cold" or "poorly immunogenic" tumor.

Checkpoint Immunotherapy in Pediatric Oncology: Will We Say Checkmate Soon?

Immune checkpoint inhibitors (ICIs) are a relatively new class of immunotherapy which bolsters the host immune system by "turning off the brakes" of effector cells (e.g., CTLA-4, PD-1, PD-L1). Although their success in treating adult malignancy is well documented, their utility in pediatric cancer has not yet been shown to be as fruitful. We review ICIs, their use in pediatric malignancies, and active pediatric clinical trials, exemplifying some of adult efforts that could be related to pediatric future trials and complications of ICI therapy. Through our review, we propose the consideration of ICI as standard therapy in lymphoma and various solid tumor types, especially in relapsed or refractory (R/R) disease. However, further studies are needed to demonstrate ICI effectiveness in pediatric leukemia.

Functionalized GD2 Electrochemical Immunosensor to Diagnose Minimum Residual Disease of Bone Marrow in Neuroblastoma Effectively

Neuroblastoma (NB) is known as the "king of childhood tumors" due to its highly metastatic, recurrence-prone, and difficult-to-treat characteristics. International Neuroblastoma Risk Grading Group (INRG) has recommended GD2, a disialoganglioside expressed on neuroectodermal tumor cells, as the target for detecting minimal residual disease in bone marrow metastases of high-risk neuroblastoma in children. Therefore, accurately identifying GD2-positive cells is crucial for diagnosing children with high-risk NB. Here, we designed a graphene/AuNP/GD2 Ab-functionalized electrochemical biosensor for GD2 detection. A three-electrode system was processed using a screen-printed technique with a working electrode of indium tin oxide, a counter electrode of carbon, and a reference electrode of silver/silver chloride. Graphene/AuNPs were modified on the indium tin oxide electrode using chronoamperometric scans, and then, the GD2 antibody was modified on the biosensor by electrostatic adsorption to achieve sensitive and specific detection of GD2-positive cells in bone marrow fluid. The results showed that a graphene/AuNP/GD2 Ab-functionalized electrochemical biosensor achieved GD2-positive cell detection in the range of 102 cells/mL~105 cells/mL by differential pulse voltammetry. Bone marrow fluid samples from 12 children with high-risk NB were retained for testing on our biosensor and showed 100% compliance with the clinical application of the gold-standard immunocytochemical staining technique for detecting GD2-positive cells qualitatively. The GD2-based electrochemical assay can accurately detect children with high-risk NB, providing a rapidly quantitative basis for clinical diagnosis and treatment.

Model for predicting prognosis and immunotherapy based on CD+8 T cells infiltration in neuroblastoma

BACKGROUND

Neuroblastoma (NBL) is an extracranial malignant tumor in children deriving from the neural crest in the sympathetic nervous system. Although various immunotherapy interventions have made significant breakthroughs in many adult cancers, the efficacy of these immunotherapies was still limited in NBL. NBL has low immunogenicity which results in a lack of tumor-infiltrating T lymphocytes in the tumor microenvironment (TME). Moreover, tumor cells can wield many immune evasion strategies both in the TME and systemically to impede lymphocyte infiltration and activation. All these factors hamper the anti-tumor effects of CD8+ T cells during immunotherapy and the levels of infiltrating CD8+ T cells correlate with therapy response.

MATERIALS AND METHODS

In this study, we utilized multidimensional bioinformatic methods to establish a risk model based on CD8+ T cells -related genes (CD8+ TRGs).

RESULTS

We obtained 33 CD8+ TRGs with well-predictive ability for prognosis in both GSE49711 and E-MTAB-8248 cohorts. Then, 12 CD8+ TRGs including HK2, RP2, HPSE, ELL2, GFI1, SLC22A16, FCGR3A, CTSS, SH2D1A, RBP5, ATF5, and ADAM9 were finally identified for risk model construction and validation. This model revealed a stable performance in prognostic prediction of the overall survival (OS) and event-free survival (EFS) in patients with NBL. Additionally, our research indicated that the immune and stromal scores, immune-related pathways, immune cell infiltration, the expression of major histocompatibility complex (MHC) and immune checkpoint molecules, immunotherapy response, and drug susceptibility revealed significant differences between high and low-risk groups.

CONCLUSIONS

According to our analyses, the constructed CD8+ TRGs-based risk model may be promising for the clinical prediction of anti-tumor therapy responses and prognoses in NBL.

Long-Term Survival of Neuroblastoma Patients Receiving Surgery, Chemotherapy, and Radiotherapy: A Propensity Score Matching Study

Neuroblastoma is the most common extracranial solid malignancy in children. This study was undertaken to determine the long-term survival of neuroblastoma patients receiving conventional therapeutics (surgery, chemotherapy, and radiotherapy). The neuroblastoma patients examined were registered in the Surveillance, Epidemiology and End Results (SEER) database (1975-2016). Using propensity score matching analysis, the patients were paired by record depending on whether they received surgery, chemotherapy, or radiotherapy. Univariate and multivariate analyses of the disease-specific survival of the paired patients were performed by the log-rank test and Cox regression assay. A total of 4568 neuroblastoma patients were included in this study. During 1975-2016, the proportion of histopathological grade III/IV cases receiving surgery gradually increased, while the number of patients with tumors of grade I to IV undergoing chemotherapy or radiotherapy was stable or even decreased. After propensity score analysis, for Grade I + II and Grade III tumors, surgery obviously improved the disease-specific survival of patients, while chemotherapy was unfavorable for patient prognosis, and radiotherapy exerted no obvious effect on the patients. However, no matter what treatment was chosen, the patients with advanced-histopathological-grade tumors had a poor prognosis. Meanwhile, for all histopathological grades, the patients receiving surgery and subsequent chemotherapy or radiotherapy suffered from worsen disease-specific survival than those simply undergoing surgery. Fortunately, the negative effects of surgery, chemotherapy, or radiotherapy improved gradually over time. Surgery improved the long-term survival of the neuroblastoma patients, while chemotherapy and radiotherapy exerted an unfavorable impact on patient outcome. These results provide an important reference for the clinical treatment of neuroblastoma.

The deubiquitinating enzyme MINDY2 promotes pancreatic cancer proliferation and metastasis by stabilizing ACTN4 expression and activating the PI3K/AKT/mTOR signaling pathway

The pathogenic mechanisms of pancreatic cancer (PC) are still not fully understood. Ubiquitination modifications have a crucial role in tumorigenesis and progression. Yet, the role of MINDY2, a member of the motif interacting with Ub-containing novel DUB family (MINDY), as a newly identified deubiquitinating enzyme, in PC is still unclear. In this study, we found that MINDY2 expression is elevated in PC tissue (clinical samples) and was associated with poor prognosis. We also found that MINDY2 is associated with pro-carcinogenic factors such as epithelial-mesenchymal transition (EMT), inflammatory response, and angiogenesis; the ROC curve suggested that MINDY2 has a high diagnostic value in PC. Immunological correlation analysis suggested that MINDY2 is deeply involved in immune cell infiltration in PC and is associated with immune checkpoint-related genes. In vivo and in vitro experiments further suggested that elevated MINDY2 promotes PC proliferation, invasive metastasis, and EMT. Meanwhile, actinin alpha 4 (ACTN4) was identified as a MINDY2-interacting protein by mass spectrometry and other experiments, and ACTN4 protein levels were significantly correlated with MINDY2 expression. The ubiquitination assay confirmed that MINDY2 stabilizes the ACTN4 protein level by deubiquitination. The pro-oncogenic effect of MINDY2 was significantly inhibited by silencing ACTN4. Bioinformatics Analysis and Western blot experiments further confirmed that MINDY2 stabilizes ACTN4 through deubiquitination and thus activates the PI3K/AKT/mTOR signaling pathway. In conclusion, we identified the oncogenic role and mechanism of MINDY2 in PC, suggesting that MINDY2 is a viable candidate gene for PC and may be a therapeutic target and critical prognostic indicator.

Combined mitoxantrone and anti-TGFβ treatment with PD-1 blockade enhances antitumor immunity by remodelling the tumor immune landscape in neuroblastoma

Background

Poor infiltration of functioning T cells renders tumors unresponsive to checkpoint-blocking immunotherapies. Here, we identified a combinatorial in situ immunomodulation strategy based on the administration of selected immunogenic drugs and immunotherapy to sensitize poorly T-cell-infiltrated neuroblastoma (NB) to the host antitumor immune response.

Methods

975A2 and 9464D NB cell lines derived from spontaneous tumors of TH-MYCN transgenic mice were employed to study drug combinations able of enhancing the antitumor immune response using in vivo and ex vivo approaches. Migration of immune cells towards drug-treated murine-derived organotypic tumor spheroids (MDOTS) were assessed by microfluidic devices. Activation status of immune cells co-cultured with drug-treated MDOTS was evaluated by flow cytometry analysis. The effect of drug treatment on the immune content of subcutaneous or orthotopic tumors was comprehensively analyzed by flow-cytometry, immunohistochemistry and multiplex immunofluorescence. The chemokine array assay was used to detect soluble factors released into the tumor microenvironment. Patient-derived organotypic tumor spheroids (PDOTS) were generated from human NB specimens. Migration and activation status of autologous immune cells to drug-treated PDOTS were performed.

Results

We found that treatment with low-doses of mitoxantrone (MTX) recalled immune cells and promoted CD8⁺ T and NK cell activation in MDOTS when combined with TGFβ and PD-1 blockade. This combined immunotherapy strategy curbed NB growth resulting in the enrichment of a variety of both lymphoid and myeloid immune cells, especially intratumoral dendritic cells (DC) and IFNγ- and granzyme B-expressing CD8⁺ T cells and NK cells. A concomitant production of inflammatory chemokines involved in remodelling the tumor immune landscape was also detected. Interestingly, this treatment induced immune cell recruitment against PDOTS and activation of CD8⁺ T cells and NK cells.

Conclusions

Combined treatment with low-dose of MTX and anti-TGFβ treatment with PD-1 blockade improves antitumor immunity by remodelling the tumor immune landscape and overcoming the immunosuppressive microenvironment of aggressive NB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02525-9.