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Oral Presentation

Tumor

Comparative Single-Cell Sequencing of Primary Versus Recurrent Glioblastoma Defines Cellular States Associated with Therapy Resistance

Saturday, May 4, 2024
2:04 PM – 2:08 PM CT
Location:  S401ab
Disclosure(s):
Arushi Tripathy, Neurosurgery Resident: No financial relationships to disclose
Introduction: Glioblastoma (GBM) is an aggressive tumor composed of multiple clonal populations. Resistance to therapy is a GBM hallmark. Radiation and temozolomide treatment are found to induce intratumoral heterogeneity and glial stem cell plasticity within the primary tumor. This reprogramming of transcriptional activity generates therapy-resistant clonal populations.
Single-cell RNA sequencing studies of primary GBM have defined various tumor cellular states: AC-like (astrocyte-like), NPC-like (neuronal precursor-like), OPC-like (oligodendrocyte precursor-like) and MES-like (mesenchymal-like). These studies have also defined the immune components and the normal brain cells associated with primary GBM. However, no prior studies perform single-cell analysis of recurrent GBM.

Methods: To define the tumor landscape at recurrence, we performed single-cell RNA sequencing of 180K cells from stereotactic biopsy samples obtained from 11 patients after failure of therapeutic interventions. A corresponding cohort of 240K cells were sequenced from primary tumors obtained from 13 patients. We performed cellular state analyses of tumor cells in both the primary and recurrent samples, including matched longitudinal samples.

Results: Primary GBM demonstrated higher fractions of AC-like (0.55), compared to NPC-like (0.10), OPC-like (0.20) and MES-like (0.15) cells. Conversely, recurrent tissues demonstrated very low AC-like (0.09) but elevated NPC-like (0.23), OPC-like (0.40) and MES-like (0.27) cells.

Conclusion : Our analysis reveals a significant decrease in AC-like cells and corresponding increase in MES-like, OPC-like, NPC-like cells at recurrence. Experimentally, using known markers for each cellular state we have also performed immunofluorescence analysis and validated this change in proportions of each cellular state between primary and recurrent GBM. We are currently performing trajectory analysis to identify genes and transcription programs activated during recurrence. Our efforts to generate a comprehensive recurrent GBM atlas will allow further investigation into the genetic and tumor microenvironmental determinants of therapeutic resistance, which in turn will provide insights crucial to the development of novel therapeutic mechanisms.