Caveolin-1 regulates context-dependent signaling and survival in Ewing sarcoma

Area of Science:

• Oncology
• Cell Biology
• Molecular Biology

Background:

• Cancer cell plasticity is crucial but poorly understood.
• Caveolin-1 (Cav-1) organizes plasma membrane domains and influences cell signaling.
• Ewing sarcoma (EwS) exhibits plasticity, necessitating investigation into survival mechanisms.

Purpose of the Study:

• To identify regulators of survival signaling in Ewing sarcoma (EwS).
• To investigate the role of Caveolin-1 (Cav-1) in EwS cell subpopulations.
• To elucidate the mechanisms underlying enhanced survival in specific EwS cell states.

Main Methods:

• Single-cell analyses to identify and characterize EwS subpopulations.
• Comparative analysis of gene expression, morphology, and survival capabilities.
• Investigation of signaling pathways, specifically PI3K/AKT, in relation to Cav-1 and CD99 expression.

Main Results:

• A distinct subpopulation of EwS cells (CD99 High) was identified, co-expressing high levels of CD99 and Caveolin-1 (Cav-1).
• CD99 High cells demonstrated enhanced survival under chemotherapy and in vivo conditions compared to CD99 Low cells.
• Elevated Cav-1 in CD99 High cells was shown to orchestrate PI3K/AKT survival signaling via spatial regulation of PI3K activity at the cell surface.

Conclusions:

• Caveolin-1 (Cav-1) acts as a context-dependent regulator of survival signaling in Ewing sarcoma (EwS).
• The CD99 High state, marked by high Cav-1, establishes a distinct survival signaling network.
• CD99 serves as a reliable marker for identifying these survival-enhanced EwS subpopulations, independent of its direct role in the pathway.