Chehyun Nam

Differential H3K27ac peak analysis.

Transcriptional intratumoral heterogeneity (ITH) is a hallmark of aggressive cancers. Investigation into the ITH programs that drive tumor metastasis and immune evasion could help identify potential treatment and prevention approaches. Through single-cell RNA sequencing analysis of upper aerodigestive squamous cell carcinoma (UASCC) cells and patient tumors, we uncovered a hybrid epithelial–mesenchymal transition (hEMT) ITH program linked to metastatic dissemination. The transcription factor ETS1 was identified as a master regulator of the hEMT program, directly activating prometastatic genes and promoting distant spread in vivo. Unexpectedly, ETS1 also orchestrated an immune-cold tumor microenvironment by transcriptionally activating STAT1 and CD274 (PD-L1), suppressing T lymphocyte infiltration, and elevating immune checkpoint molecules. Clinically, high ETS1 expression in tumors strongly correlated with poor survival and resistance to immune checkpoint blockade across multiple cohorts. Drug screening demonstrated that ETS1-high cancers were vulnerable to HSP90 inhibitors (e.g., alvespimycin), which suppress ETS1 by disrupting hypoxia-inducible factor 1 alpha–mediated transcriptional activation. Together, this work reveals ETS1 as a dual driver of tumor distal metastasis and immune evasion in UASCC, while nominating HSP90 inhibition as a tailored treatment strategy for ETS1-driven tumors. These findings provide a roadmap for targeting aggressive ITH subsets and overcoming immunotherapy resistance. Significance:Transcriptional intratumoral heterogeneity drives metastasis and immune evasion via an ETS1-regulated hybrid EMT program, which can be targeted with HSP90 inhibitors to treat aggressive, immunotherapy-resistant tumors.

Overlapped genes between ETS1 ChIP-Seq data.

Functional validation of ETS1 in UASCC cell lines.

Immune profiling in ETS1-driven tumor models.

HSP90 inhibition suppresses ETS1-driven cell migration in UASCC cells.

Correlation between ETS1 expression and protein levels of its target genes.

ETS1 modulates sensitivity to HSP90 inhibition in UASCC cells.

ETS1 expression is associated with poor immunotherapy response.

Regulation of ETS1 and its association with HIF1A–HSP90 signaling.