ETS1-Driven Nucleolar Stress Orchestrates OLR1+ Macrophage Crosstalk to Sustain Immunosuppressive Microenvironment in Clear Cell Renal Cell Carcinoma.

While hypoxia-driven nucleolar stress (NS) has been recognized as a critical modulator of the immunosuppressive tumor microenvironment in clear cell renal cell carcinoma (ccRCC), its mechanistic contribution to disease progression remains poorly defined. To address this gap, we systematically mapped NS-associated molecular landscapes through integrated spatial transcriptomics and single-cell RNA sequencing of ccRCC specimens. Our analysis stratified tumors into two distinct NS subtypes, revealing that high-NS tumors exhibit aggressive clinical behavior, elevated expression of immunosuppressive checkpoints, and significantly reduced survival. At single-cell resolution, high-NS malignant cells displayed enhanced proliferative activity, glycolytic metabolic reprograming, and marked chromosomal instability. Mechanistic investigations demonstrated that hypoxia-induced ETS1 activation orchestrates NS via the MYC/NPM1/DDX17 signaling axis, directly promoting tumor proliferation and metabolic adaptation in preclinical models. Spatial multiomics further uncovered coordinated niche formation between high-NS cells and OLR1+ macrophages, with ligand-receptor profiling identifying the EDN1-EDNRA-OLR1 axis as a central mediator of this immunosuppressive crosstalk. Functional validation in syngeneic mouse models confirmed that ETS1 overexpression accelerates tumor growth while enriching OLR1+ macrophages with immunosuppressive phenotypes. Clinically, high OLR1+ macrophage infiltration correlated with shorter survival across independent cohorts. These findings establish a hypoxia-ETS1-NS-macrophage axis as a key mechanism sustaining ccRCC progression and highlight actionable targets for disrupting protumorigenic immune niches through modulation of the NS pathway.