A novel lncRNA-mediated signaling axis governs cancer stemness and splicing reprogramming in hepatocellular carcinoma with therapeutic potential.

[BACKGROUND] Aberrant alternative splicing (AS) contributes to cancer stemness and progression in hepatocellular carcinoma (HCC). However, the regulatory roles of long noncoding RNAs (lncRNAs) in linking AS dysregulation to tumor stemness remain elusive.

[METHODS] We performed integrated bulk and single-cell RNA-Seq analyses combined with functional assays to identify key lncRNAs associated with splicing regulation and cancer stemness in HCC. Mechanistic studies were conducted to elucidate the molecular interplay between lncRNAs, splicing factors, and transcriptional regulators. Drug sensitivity assays were used to evaluate therapeutic potential.

[RESULTS] Global analysis revealed increased splicing regulator activity during hepatocellular carcinoma (HCC) progression, which correlated with poor prognosis. This splicing dysregulation led us to identify 28 lncRNAs that connect aberrant splicing with cancer stemness. Among these, RAB30-DT was significantly overexpressed in malignant epithelial cells and associated with advanced tumor stage, stemness features, genomic instability, and poor patient prognosis. Functional assays demonstrated that RAB30-DT promotes proliferation, migration, invasion, colony and sphere formation in vitro, and tumor growth in vivo. Mechanistically, RAB30-DT is transcriptionally activated by CREB1 and directly binds and stabilizes the splicing kinase SRPK1, facilitating its nuclear localization. This interaction broadly reshapes the AS landscape, including splicing of the cell cycle regulator CDCA7, to drive tumor stemness and malignancy. Importantly, pharmacological disruption of the CREB1-RAB30-DT-SRPK1 axis sensitizes HCC cells to targeted therapies.

[CONCLUSIONS] Our study reveals a novel lncRNA-mediated signaling axis that integrates transcriptional regulation and splicing reprogramming to sustain cancer stemness and progression in HCC. Targeting this axis offers promising therapeutic opportunities for HCC treatment.