Aly as a Key Regulator of DNA Repair and Immune Evasion in Esophageal Squamous Cell Carcinoma Radioresistance.

Abstract

ESCC is frequently refractory to radiotherapy, in part due to efficient DNA damage repair and an immunosuppressive tumor microenvironment. We investigated whether ALYREF (Aly) coordinates radioresistance and immune evasion in ESCC. Aly expression and clinical associations were analyzed in TCGA cohorts and validated by immunohistochemistry in an independent ESCC cohort. Aly was genetically silenced or overexpressed in ESCC cell lines followed by irradiation, clonogenic survival, ROS and apoptosis assays. Multi-omics analyses and mechanistic studies (protein interaction modeling, immunofluorescence, and DNA damage readouts) were performed to define pathways linking Aly to radioresponse and immune contexture. Aly was overexpressed in ESCC and associated with adverse clinical outcomes. Aly depletion suppressed ESCC growth and enhanced radiosensitivity, characterized by increased radiation-induced ROS and apoptosis and reduced clonogenic survival. Aly loss was accompanied by changes consistent with impaired resolution of DNA double-strand break repair and activation of inflammatory signaling. Mechanistically, Aly engaged REV7-associated nuclear programs and Hsp70-linked cytoprotective signaling, supporting DNA damage tolerance and survival after irradiation, and correlated with an immunosuppressive contexture. Aly functions as a dual regulator of ESCC radioresistance by integrating DNA repair competence and immune suppression. Targeting Aly may represent a strategy to radiosensitize ESCC and potentially improve responses to combined radiotherapy-immunotherapy.