Dysregulated RNA splicing events produce transcripts that facilitate esophageal squamous cell carcinoma (ESCC) progression, but how this splicing process is abnormally regulated remains elusive. Here, we unveiled a novel alternative splicing axis of BOLA3 transcripts and its regulator HNRNPC in ESCC. The long-form BOLA3 (BOLA3-L) containing exon 3 exhibited high expression levels in ESCC and was associated with poor prognosis. Functional assays demonstrated the protumorigenic function of BOLA3-L in ESCC cells. Additionally, HNRNPC bound to BOLA3 mRNA and promoted BOLA3 exon 3 inclusion forming BOLA3-L. High HNRNPC expression was positively correlated with the presence of BOLA3-L and associated with an unfavorable prognosis. HNRNPC knockdown effectively suppressed the malignant biological behavior of ESCC cells, which were significantly rescued by BOLA3-L overexpression. Moreover, BOLA3-L played a significant role in mitochondrial structural and functional stability. E2F7 acted as a key transcription factor that promoted the upregulation of HNRNPC and inclusion of BOLA3 exon 3. Our findings provided novel insights into how alternative splicing contributes to ESCC progression.
Female ; Humans ; Male ; Mice ; Alternative Splicing ; Cell Line, Tumor ; Disease Progression ; Esophageal Neoplasms/pathology* ; Esophageal Squamous Cell Carcinoma/pathology* ; Exons/genetics* ; Gene Expression Regulation, Neoplastic ; Heterogeneous-Nuclear Ribonucleoprotein Group C/metabolism* ; Prognosis ; RNA, Long Noncoding/metabolism* ; Animals

OBJECTIVES: This work aimed to construct N6-methyladenosine (m⁶A) regulator-based prognostic signature and evaluate the prognostic value and the intervention on tumor immune microenvironment of this m⁶A risk signature. METHODS: Using transcriptome and clinical data of head and neck squamous cell carcinoma (HNSCC) from The Cancer Genome Atlas (TCGA), we profiled m⁶A regulators and constructed an m⁶A risk signature. The relationship between m⁶A modulation and immune function was studied by differential gene expression, cell type enrichment, and correlation analyses. RESULTS: Fifteen m⁶A regulators had aberrant expression in HNSCC. A three-gene m⁶A prognostic signature (i.e., YTHDC2, IGF2BP2, and HNRNPC) was constructed and identified as an independent prognostic indicator for HNSCC. The m⁶A regulator signature-based high-risk group revealed pro-tumoral immune microenvironment due to the dysregulation of immune-related gene expression, abnormal enrichment of multiple immunocytes, and production of immunoregulatory factors. CONCLUSIONS This comprehensive analysis of m⁶A regulators and tumor immune landscape in HNSCC revealed that the m⁶A signature of YTHDC2, IGF2BP2, and HNRNPC could serve as a promising biomarker for monitoring HNSCC development and may be a potential target for tumor therapy in the future.
Humans ; Squamous Cell Carcinoma of Head and Neck/genetics* ; Gene Expression Regulation, Neoplastic ; Prognosis ; Head and Neck Neoplasms/genetics* ; Tumor Microenvironment/genetics* ; RNA-Binding Proteins/genetics* ; Heterogeneous-Nuclear Ribonucleoprotein Group C/genetics* ; RNA Helicases