Abstract PR001: Immunocompetent models reveal lineage state-specific immune escape mechanisms in neuroblastoma
Piotr K. Jung, Matthew Shapiro, Sridhar M. Veluvolu, Kevin Bayingana, Alaa Narch, Cara Toland, Annette Vu, Hamid Bassiri, Michael D. Hogarty, Timour Baslan, Adam J. WolpawAbstract
Introduction
Cell state heterogeneity has a profound impact on tumor development, progression, and treatment resistance. In neuroblastoma (NB), two lineage states have been described: an adrenergic (ADRN) state that comprises the majority of tumor cells and a mesenchymal (MES) population that is therapy-resistant and enriched in relapse. We and others have shown that the human MES state has higher antigen presentation and is more susceptible to immune cell killing than the ADRN state. However, immunocompetent models of these states have not been available to investigate how these distinctions impact tumors in vivo. Here we define and characterize fully immunocompetent, isogenic lineage state models and use them to identify state-specific mechanism of immune escape. Methods We isolated 15 tumors that developed spontaneously in homozygous Th-MYCN transgenic mice, subcutaneously passaged a portion directly into wild-type mice, created a tumor-derived cell line, and implanted the cell line to form a cell line allograft. Cell lines and tumors were characterized by immunoblotting, immunohistochemistry, RNAseq, and low pass WGS. Tumors were also analyzed by CUT&Tag for H3K27Ac and by spectral flow cytometry to evaluate surface target expression and immune microenvironment composition. A subset of tumors were treated with an anti-GD2 antibody. Results We found that spontaneous Th-MYCN tumors and directly passaged allografts had strong protein expression of ADRN lineage markers, high surface GD2, high levels of transcripts in a previously defined ADRN gene signature, and a network of H3K27Ac-marked transcription factors that overlapped with human ADRN cell lines and tumors. Directly passaged tumors responded robustly to anti-GD2 antibody treatment. In contrast, cell lines and cell line allografts had strong protein expression of MES lineage markers, lacked GD2, and expressed transcripts in a previously defined MES signature. Cell line allografts had a network of H3K27Ac-marked transcription factors consistent with those found in human MES cell lines and tumors. Murine allografts with MES features had stronger signatures of inflammation and antigen presentation than ADRN-like tumors. Comparing the tumors with MES features to those with ADRN features, we found that MES tumors had a much higher percentage of CD45+ immune cells overall and notably a higher percentage of CD163+/MHCII- M2-like macrophages and more CD4+/CD25+ regulatory T cells. Conclusions We have developed tractable, isogenic NB lineage state models in immunocompetent mice that transcriptionally and epigenetically phenocopy the human lineage states. ADRN tumors have limited antigen presentation and immune infiltration. In contrast, MES tumors have high levels of antigen presentation and immune infiltration, but the infiltrating cells are dominated by immunosuppressive cell populations. These finding support lineage-specific mechanisms of immune escape. Ongoing experiments focusing on the impact of elimination of immunosuppressive immune cells on the growth of these tumors are underway.
Citation Format:
Piotr K. Jung, Matthew Shapiro, Sridhar M. Veluvolu, Kevin Bayingana, Alaa Narch, Cara Toland, Annette Vu, Hamid Bassiri, Michael D. Hogarty, Timour Baslan, Adam J. Wolpaw. Immunocompetent models reveal lineage state-specific immune escape mechanisms in neuroblastoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Bridging Discovery and Clinical Impact in Pediatric Cancer; 2026 Sep 22-25; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86(18_Suppl_1):Abstract nr PR001.