SNORA28 Promotes Proliferation and Radioresistance in Colorectal Cancer Cells through the STAT3 Pathway by Increasing H3K9 Acetylation in the LIFR Promoter

Abstract Radiotherapy is essential for treating colorectal cancer (CRC), especially in advanced rectal cancer. However, the low radiosensitivity of CRC cells greatly limits radiotherapy efficacy. Small nucleolar RNAs (snoRNAs) are a class of noncoding RNA that primarily direct post‐transcriptional modifications of ribosomal RNAs (rRNAs), small nuclear RNAs (snRNAs), and other cellular RNAs. While snoRNAs are involved in tumor progression and chemoresistance, their association with radiosensitivity remains largely unknown. Herein, SNORA28 is shown highly expressed in CRC and is positively associated with poor prognosis. Furthermore, SNORA28 overexpression enhances the growth and radioresistance of CRC cells in vitro and in vivo. Mechanistically, SNORA28 acts as a molecular decoy that recruits bromodomain‐containing protein 4 (BRD4), which increases the level of H3K9 acetylation at the LIFR promoter region. This stimulates LIFR transcription, which in turn triggers the JAK1/STAT3 pathway, enhancing the proliferation and radioresistance of CRC cells. Overall, these results highlight the ability of snoRNAs to regulate radiosensitivity in tumor cells and affect histone acetylation modification in the promoter region of target genes, thus broadening the current knowledge of snoRNA biological functions and the mechanism underlying target gene regulation.