Integrated Single-Nucleus and Spatial Transcriptomics Elucidate Heterogeneity and Hypoxia-Driven Organization of...

Area of Science:

• Neuro-oncology
• Genomics
• Molecular Biology

Background:

• Supratentorial ependymomas are aggressive brain tumors with significant molecular variability.
• Hypoxia's role in this heterogeneity and its impact on tumor biology are not fully understood.
• Effective treatment strategies require a deeper comprehension of ependymoma's underlying biological mechanisms.

Purpose of the Study:

• To investigate the cellular and spatial landscape of supratentorial ependymoma using advanced transcriptomic techniques.
• To identify novel molecular programs and understand their association with tumor characteristics and patient outcomes.
• To elucidate the role of hypoxia in the spatial organization and higher-order architecture of these tumors.

Main Methods:

• Single-nucleus and spatial transcriptomics were applied to supratentorial ependymoma samples (n=63 and n=30, respectively).
• Transcriptional consensus programs were characterized to identify distinct molecular signatures.
• Spatial scoring algorithms were developed to analyze the spatial distribution of molecular features and identify drivers of organization.
• A generalized model of tumor architecture was constructed based on spatial associations and defined zones.

Main Results:

• Two novel transcriptional programs associated with extracellular matrix remodeling and ZFTA fusion identity were identified.
• These programs correlated with unfavorable patient outcomes and were specific to ZFTA fusion-positive ependymomas.
• Hypoxia was identified as a potential driver of spatial organization within the tumor microenvironment.
• Distinct tumor zones, including hypoxic regions, showed varying immune cell infiltration, with highest presence in hypoxic areas.

Conclusions:

• The study reveals key molecular programs and spatial organization patterns in supratentorial ependymomas.
• Hypoxia plays a significant role in shaping the tumor's spatial landscape and heterogeneity.
• Findings provide crucial insights into the biology of ZFTA fusion-positive ependymomas, potentially guiding the development of novel, targeted therapeutic strategies.