Ewing sarcoma breakpoint region 1-Friend leukemia integration 1 transcription factor complex (EWS-FLI1 complex)

The EWS-FLI1-dependent transcriptional complex is the primary oncogenic driver of Ewing sarcoma, resulting from a chromosomal translocation t(11;22)(q24;q12) that fuses the EWSR1 gene with the FLI1 gene. This fusion protein acts as an aberrant transcription factor that both activates and represses a vast network of genes by binding to GGAA-microsatellite response elements and recruiting various co-regulators, such as RNA Helicase A (DHX9), LSD1, and the BAF complex (Riggi et al., 2014, Cancer Discovery). By altering the epigenetic landscape and transcriptional output of the cell, the complex promotes uncontrolled proliferation, survival, and the characteristic undifferentiated phenotype of Ewing sarcoma cells (Sankar et al., 2014, Genes & Development). Because EWS-FLI1 is unique to tumor cells and essential for their survival, it is a highly specific therapeutic target. Current pharmacological approaches focus on disrupting its interaction with essential protein partners, inhibiting its downstream enzymatic effectors, or inducing its degradation (Grohar et al., 2011, JNCI; Hong et al., 2014, Cancer Research).

Other names

EWSR1-FLI1 fusion protein complexEWS-FLI1 oncoprotein complexEWS-FLI1 transcriptional apparatust(11;22)(q24;q12) fusion product

Small molecule inhibitors like TK216 and YK-4-279 disrupt the protein-protein interaction between EWS-FLI1 and RNA Helicase A (RHA/DHX9), leading to apoptosis in Ewing sarcoma cells (Erkizan et al., 2009, Nature Medicine; Ludwig et al., 2021, JCO). Other strategies include inhibiting associated epigenetic modifiers like LSD1 (Seclidemstat) to reverse EWS-FLI1-mediated transcriptional repression (Pishas et al., 2018, Cancer Research) or using Lurbinectedin to redistribute the fusion protein from active chromatin sites (Harlow et al., 2016, Cancer Cell).