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

Celecoxib is a selective inhibitor of cyclooxygenase-2 (COX-2) that is a critical factor in carcinogenesis, but precise mechanism of its action remains to be elucidated. Here we evaluated the inhibitory effect of celecoxib on cell growth of human oral squamous cell carcinoma (OSCC) YD-10B, which was established to be used as in vitro OSCC model, and identified celecoxib-regulated protein by proteomics techniques. Celecoxib (IC50=37 micrometer) inhibited the growth of YD-10B cells with the decrease of COX-2 protein expression. Its inhibition could be linked in the arrest of G1 phase with increased levels of p(27)protein, a specific CDK inhibitor. Using proteomics, the 10- to 20-fold increase of heterogeneous nuclear ribonuclear protein C (hnRNP C), which has been suggested to be related with the translation of p(27)mRNA, was observed in celecoxib-treated YD-10B cells. In summary, celecoxib has a potential to induce the protein expression of hnRNP C and its increase subsequently induce the translation of p(27)mRNA, which trigger the inhibition of cell growth via p(27)-regulated cell cycle arrest in YD-10B cells. In addition, YD-10B cells could be useful to study the pathological mechanism of OSCC.
Tumor Cells, Cultured ; Tongue Neoplasms/metabolism/pathology ; Sulfonamides/*pharmacology ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Pyrazoles/*pharmacology ; Proteomics/methods ; Male ; Immunoblotting ; Humans ; Heterogeneous-Nuclear Ribonucleoprotein Group C/analysis/*metabolism ; Electrophoresis, Gel, Two-Dimensional ; Cyclooxygenase Inhibitors/pharmacology ; Cyclooxygenase 2/metabolism ; Cyclin-Dependent Kinase Inhibitor p27/analysis/metabolism ; Cell Survival/drug effects ; Cell Proliferation/*drug effects ; Cell Line, Tumor ; Cell Cycle/drug effects ; Carcinoma, Squamous Cell/metabolism/pathology ; Aged ; Actins/metabolism