Transcriptome profiling of Ewing sarcomas - treatment resistance pathways and IGF-dependency

Area of Science:

• Oncology
• Molecular Biology
• Genomics

Background:

• Ewing sarcomas (ESs) are aggressive cancers driven by EWS fusion genes.
• Predicting treatment response and tumor progression in ES remains a clinical challenge.

Purpose of the Study:

• To investigate whole-transcriptome sequencing (RNA-seq) for detecting patterns linked to chemotherapy response and progression in ES.
• To explore the role of Insulin-like Growth Factor 2 (IGF2) in ES clinical behavior and treatment outcomes.

Main Methods:

• RNA-sequencing was performed on 13 ES patient samples.
• Analysis of differentially expressed genes and pathways associated with clinical outcomes.
• Functional investigation of IGF2 effects on ES cell lines and validation in 14 additional patients.

Main Results:

• RNA-seq identified distinct gene signatures associated with chemotherapy response, overall survival, and post-treatment progression.
• Imprinting-independent IGF2 expression via promoter P3 was linked to aggressive clinical courses.
• High IGF2 expression correlated with shorter overall survival and induced proliferation in ES cell lines.

Conclusions:

• Transcriptome analysis, particularly IGF2 expression patterns, can predict Ewing sarcoma clinical behavior.
• An IGF-dependent signature suggests a stem cell-like phenotype in a subset of ES.
• IGF inhibition presents a potential therapeutic strategy for select ES patients when combined with standard treatment.