Immune Profile of the Neuro-2a Mouse Neuroblastoma Model by Flow Cytometry

Neuroblastoma is an extracranial tumor that arises from neural crest-derived progenitor cells. It is the most prevalent solid tumor in childhood and the most common tumor in infants less than one year of age. With up to 800 new cases diagnosed each year, in spite of aggressive multi-modal therapeutic approaches, the 5-year survival rate in patients with high-risk neuroblastoma remains poor at <50 percent.1 This necessitates novel therapies that improve clinical outcome. To this end, the development of drugs that boost host anti-tumor responses to overcome the immunosuppressive environment in neuroblastoma has drawn attention.

For example, treatment with dinutuximab, an anti-GD2 monoclonal antibody, has been demonstrated to trigger neuroblastoma regression through an antibody-dependent cellular cytotoxicity mechanism that involves natural killer (NK) T cells and macrophages. Dinutuximab has been shown to increase the two-year event free and overall survival rates in patients with high-risk neuroblastoma and has been approved by the FDA.2 Furthermore, preclinical studies using anti-CTLA-4 antibody therapy has demonstrated that immune checkpoint blockade can control tumor growth in Neuro-2a tumor-bearing mice via an NK and CD8+ T cell-dependent mechanism.3 As the mechanism of host defense against neuroblastoma becomes more clear, opportunities are created for the development of new single agent and combination therapies that bolster anti-tumor defense.

Figure 1: Analysis of lymphocyte subsets in Neuro-2a-derived tumors by flow cytometry.

Flow cytometry is an ideal methodology for the analysis of immunomodulatory effects triggered by drug candidates in vivo. In the Neuro-2a mouse model for neuroblastoma, the figure above illustrates how the Covance MI-CompT™ and MI-NK™ panels can be utilized to quantify baseline immune profiles, which can be instrumental in model selection and for the determination of how these profiles may shift with treatment. Tumor-derived CD4+ T cells are quantified and further analyzed for regulatory T cells (Tregs) (Fig. 1 A&B). CD8+ T cells are interrogated for proliferation and exhaustion markers (Ki-67 and PD-1, respectively) (Fig. 1 A&C). NK cells are analyzed following myeloid-derived suppressor (MDSC) cell exclusion (Fig. 1D).

Figure 2: Analysis of myeloid subsets in Neuro-2a-derived tumors by flow cytometry.

Myeloid subsets including MDSCs and M2 polarized tumor-associated macrophages (TAM) promote neuroblastoma growth and are an attractive target for novel therapies.4 The above figure illustrates how the MI-TAM™ panel can be used to profile various myeloid subsets within Neuro-2a tumors. Tumor-derived monocytic (M-) and granulocytic (G-) MDSCs are quantified (Fig 2A). Following MDSC exclusion, cells that are positive for the macrophage marker F4/80 are further analyzed for pro-tumor M2 TAMs and anti-tumor M1 TAMs (Fig. 2 B&C).

Contact Covance to learn more about how flow cytometry can advance your pre-clinical research in neuroblastoma.

Outside of Neuro-2a, Covance has evaluated the immune profile of a number of syngeneic tumor models. Click here to inquire about other models.

Covance has standardized 10-flow cytometry panels to interrogate both lymphoid and myeloid cell lineages. If your needs require specialized panels, consult with our experts to design a custom panel to meet your specific needs.

Written by: David Draper, PhD, Sr. Associate Scientist, In Vitro Services

1Speleman, F., J. R. Park, and T. O. Henderson. “Neuroblastoma: A Tough Nut to Crack.” American Society of Clinical Oncology educational book/ASCO. American Society of Clinical Oncology. Meeting. Vol. 35. 2015.

2Ploessl, Cady, et al. “Dinutuximab An Anti-GD2 Monoclonal Antibody for High-Risk Neuroblastoma.” Annals of Pharmacotherapy 50.5 (2016): 416-422.

3Williams, Emily L., et al. “Immunomodulatory monoclonal antibodies combined with peptide vaccination provide potent immunotherapy in an aggressive murine neuroblastoma model.” Clinical Cancer Research 19.13 (2013): 3545-3555.

4Pistoia, Vito, et al. “Immunosuppressive microenvironment in neuroblastoma.” Frontiers in oncology 3 (2013): 167.