Abstract Background: Radiotherapy remains one of the principal therapeutic modalities for non-small cell lung cancer (NSCLC), yet its therapeutic efficacy is frequently compromised by tumor recurrence, metastasis, and the development of radioresistance. Accumulating evidence identifies cancer stem cells (CSCs) as a critical driver of radioresistance. Therefore, elucidating the underlying molecular mechanisms and developing therapeutic targets to enhance radiosensitivity are of critical importance. Methods: To identify key mediators of adaptive radioresistance in NSCLC, we established radioresistant NSCLC cell lines through repeated cycles of irradiation and subsequently performed RNA-seq analysis comparing them with their parental counterparts. The effects of SLFN5 on radiosensitivity were evaluated by flow cytometry and colony formation assays, and further validated in vivo using a nude mouse xenograft tumor model. Cancer stem-like properties were assessed by RT-PCR, Western blot, flow cytometry, sphere formation assay, and in vivo limiting dilution tumorigenesis assays. Subsequently, we employed mass spectrometry, co-immunoprecipitation, and proximity ligation assay to identify the interaction between SLFN5 and NOTCH1. Furthermore, phase separation assay, fluorescence recovery after photobleaching, CUT Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2192.
Tang et al. (Fri,) studied this question.