2026 Proffered Presentations
S159: ENRICHMENT OF CANCER ASSOCIATED FIBROBLASTS IN RADIATION-TREATED RECURRENT OLFACTORY NEUROBLASTOMA
Esmerina Tili, PhD; Amar Dabbagh, BS; Khaled Dibs, MD; Bradley Gigax, BS; Ahmed ElGuindy; Kyle VanKovering, MD; Kyle Wu, MD; Marcelo Bonomi, MD; Daniel Prevedello, MD; Ricardo Carrau, MD; Dukagjin Blakaj, MD, PHD; Ohio State University
INTRODUCTION: Olfactory neuroblastomas (ONB), comprising 3-6% of sinonasal malignancies, are rare and aggressive. Surgery followed by radiotherapy (RT) are often considered part of standard of care treatment, yet recurrence rates remain high. This study aimed to characterize the cellular and molecular characteristics of ONB and its microenvironment (TME), explore changes leading to therapy resistance, and identify therapeutic targets.
METHODOLOGY: Spatial transcriptomics (ST) was performed on paired normal and tumor samples from two ONB patients; one newly diagnosed and untreated, and the other with recurrent (R-ONB) who had undergone RT. Bulk RNA-seq, DNA-seq, and methylome analyses are ongoing on 30 samples with four patients having pre- and post- treatment failure tumors. We also prepared organoids from three untreated and three R-ONB samples. ST analyses were performed using VisiumHD (10XGenomics), with raw data processed by SpaceRanger and integrated with H&E images. Subsequent analyses were conducted in Seurat, including unbiased clustering and identification of differentially expressed genes (DEGs) within clusters. DEGs were analyzed using GO and STRING software to annotate clusters, and were compared between tumor and normal pairs, as well as untreated and recurrent tumors.
RESULTS: Analysis revealed significant differences in predominant cell types: untreated-ONB consisted of 70% neurons, while R-ONB showed a predominance of cancer-associated fibroblasts (CAFs). CAFs, linked to poor prognosis, invasiveness, and therapy resistance, were enriched for BMP, WNT signaling, and genes involved in angiogenesis. Furthermore, they were also enriched for transcripts involved in cellular response to Ultraviolet A (UV-A) and burn wound healing, suggesting that CAFs in R-ONB potentially represent body’s response to RT.
In untreated tumor, neurons expressed high levels of neuronal lineage transcriptional factors NEURODs and Cyclin D1-CDK6 complex. In contrast, R-ONB neurons were scarce, had lost many neuronal markers, and showed signs of quiescence. R-ONB demonstrated increased oxidative phosphorylation and notable reduction of genes involved in ubiquitination and protein degradation.
Immune response analysis indicated that untreated-ONB was enriched for genes involved in leukocyte and neutrophil chemotaxis. Genes associated with T cell activation and antigen presentation were underrepresented in both tumors. In R-ONB, BCR signaling, cell chemotaxis, leukocyte migration, and overall immune responses to tumor cells were diminished while a tumor-associated macrophage (TAM) phenotype was also prevalent. Concurrently, several immune checkpoints involved in immune evasion and cancer progression were highly expressed in R-ONB.
Aligning with ST results, organoids derived from untreated-ONBs exhibited a neuron cell-like phenotype, whereas those from R-ONB patients displayed fibroblast-like cells without neuronal structures, indicating changes post-treatment.
CONCLUSION: Untreated and R-ONB tumors exhibit distinct cellular composition, TME, and growth patterns, indicating the need for tailored therapeutic approaches. Cyclin D1-CDK6 inhibitors are potential targets for untreated tumors. CAFs in R-ONB may “shield” tumor cells from therapy while creating a “scaffold” for neuronal growth, necessitating investigation of their interactions with neurons and TME for therapy. Immune-suppressive markers were identified in each tumor, emphasizing the need to explore immune checkpoints as therapeutic strategies.