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

Anti-tumor efficacy of Tγ9δ2 lymphocytes expressing anti-O-acetylated GD2 CAR in pediatric brain tumors

International audience• 2,500 characters maximum, including spaces, • no figures or tables, • abstracts should include the following separated parts: objective, methods, results and conclusion

CIBLAGE DU GANGLIOSIDE GD2 O-ACÉTYLÉ COMME NOUVELLE STRATÉGIE THÉRAPEUTIQUE ET DIAGNOSTIQUE DANS LE CANCER À CELLULES SOUCHES TUMORALES

Type de la demande A1 N° et date de dépôt EP14723706

CAR T Cell Therapy’s Potential for Pediatric Brain Tumors

International audienceMalignant central nervous system tumors are the leading cause of cancer death in children. Progress in high-throughput molecular techniques has increased the molecular understanding of these tumors, but the outcomes are still poor. Even when efficacious, surgery, radiation, and chemotherapy cause neurologic and neurocognitive morbidity. Adoptive cell therapy with autologous CD19 chimeric antigen receptor T cells (CAR T) has demonstrated remarkable remission rates in patients with relapsed refractory B cell malignancies. Unfortunately, tumor heterogeneity, the identification of appropriate target antigens, and location in a growing brain behind the blood–brain barrier within a specific suppressive immune microenvironment restrict the efficacy of this strategy in pediatric neuro-oncology. In addition, the vulnerability of the brain to unrepairable tissue damage raises important safety concerns. Recent preclinical findings, however, have provided a strong rationale for clinical trials of this approach in patients. Here, we examine the most important challenges associated with the development of CAR T cell immunotherapy and further present the latest preclinical strategies intending to optimize genetically engineered T cells’ efficiency and safety in the field of pediatric neuro-oncology

Public Health Impact of Using Biosimilars, Is Automated Follow up Relevant?

International audienceBiologic reference drugs and their copies, biosimilars, have a complex structure. Biosimilars need to demonstrate their biosimilarity during development but unpredictable variations can remain, such as micro-heterogeneity. The healthcare community may raise questions regarding the clinical outcomes induced by this micro-heterogeneity. Indeed, unwanted immune reactions may be induced for numerous reasons, including product variations. However, it is challenging to assess these unwanted immune reactions because of the multiplicity of causes and potential delays before any reaction. Moreover, safety assessments as part of preclinical studies and clinical trials may be of limited value with respect to immunogenicity assessments because they are performed on a standardised population during a limited period. Real-life data could therefore supplement the assessments of clinical trials by including data on the real-life use of biosimilars, such as switches. Furthermore, real-life data also include any economic incentives to prescribe or use biosimilars. This article raises the question of relevance of automating real life data processing regarding Biosimilars. The objective is to initiate a discussion about different approaches involving Machine Learning. So, the discussion is established regarding implementation of Neural Network model to ensure safety of biosimilars subject to economic incentives. Nevertheless, the application of Machine Learning in the healthcare field raises ethical, legal and technical issues that require further discussion

Potentiation of Anticancer Antibody Efficacy by Antineoplastic Drugs: Detection of Antibody-drug Synergism Using the Combination Index Equation

International audiencePotentiation of hostile monoclonal antibodies (mAb) by chemotherapeutic agents constitutes a valuable strategy for designing effective and safer therapy against cancer. Here we provide a protocol to identify a rational combination at the preclinical step. First, we describe a cell-based assay to assess the synergism between anticancer mAb and cytotoxic drugs, that uses the combination index equation of Chou and Talalay 1. This includes the measurement of tumor cell drug-and antibody-sensitivity using an MTT assay, followed by an automated computer analysis to calculate the combination index (CI) values. CI values of <1 indicate synergism between tested mAbs and cytotoxic agents 1. To corroborate the in vitro findings in vivo, we further describe a method to assess the combination regimen efficacy in a xenograft tumor model. In this model, the combined regimen significantly delays tumor growth, which results in a significant extended survival in comparison to single-agent controls. Importantly, the in vivo experimentation reveals that the combination regimen is well tolerated. This protocol allows the effective evaluation of anticancer drug combinations in preclinical models and the identification of rational combination to evaluate in clinical trials

UTILISATION D'UN ANTICORPS CONTRE LE GANGLIOSIDE GD2 O-ACÉTYLÉ DANS LE BUT D'AMÉLIORER LE POTENTIEL THÉRAPEUTIQUE DE MÉDICAMENTS

Type de la demande A1 N° et date de dépôt EP1782959

SIRPα-specific monoclonal antibody enables antibody-dependent phagocytosis of neuroblastoma cells

International audienceImmunotherapy with anti-GD2 monoclonal antibodies (mAbs) provides some benefits for patients with neuroblastoma (NB). However, the therapeutic efficacy remains limited, and treatment is associated with significant neuropathic pain. Targeting O-acetylated GD2 (OAcGD2) by 8B6 mAb has been proposed to avoid pain by more selective tumor cell targeting. Thorough understanding of its mode of action is necessary to optimize this treatment strategy. Here, we found that 8B6-mediated antibody-dependent cellular phagocytosis (ADCP) performed by macrophages is a key effector mechanism. But efficacy is limited by upregulation of CD47 expression on neuroblastoma cells in response to OAcGD2 mAb targeting, inhibiting 8B6-mediated ADCP. Antibody specific for the CD47 receptor SIRPα on macrophages restored 8B6-induced ADCP of CD47-expressing NB cells and improved the antitumor activity of 8B6 mAb therapy. These results identify ADCP as a critical mechanism for tumor cytolysis by anti-disialoganglioside mAb and support a combination with SIRPα blocking agents for effective neuroblastoma therapy

Targeting O-Acetyl-GD2 Ganglioside for Cancer Immunotherapy

Target selection is a key feature in cancer immunotherapy, a promising field in cancer research. In this respect, gangliosides, a broad family of structurally related glycolipids, were suggested as potential targets for cancer immunotherapy based on their higher abundance in tumors when compared with the matched normal tissues. GD2 is the first ganglioside proven to be an effective target antigen for cancer immunotherapy with the regulatory approval of dinutuximab, a chimeric anti-GD2 therapeutic antibody. Although the therapeutic efficacy of anti-GD2 monoclonal antibodies is well documented, neuropathic pain may limit its application. O-Acetyl-GD2, the O-acetylated-derivative of GD2, has recently received attention as novel antigen to target GD2-positive cancers. The present paper examines the role of O-acetyl-GD2 in tumor biology as well as the available preclinical data of anti-O-acetyl-GD2 monoclonal antibodies. A discussion on the relevance of O-acetyl-GD2 in chimeric antigen receptor T cell therapy development is also included