Differential effects of SRPK1 inhibition on HPV⁺ and HPV⁻ in cervical cancer: Transcriptome and splicing rewiring

Background: Cervical cancer (CCa) remains a major cause of cancer-related mortality worldwide, largely driven by persistent infection with high-risk human papillomavirus (hrHPV) types such as HPV16 and HPV18. The viral E6 and E7 oncoproteins disrupt the p53 and Rb tumour suppressor pathways and reprogram host RNA processing, resulting in the production of tumour-promoting splice isoforms. Serine/arginine protein kinase 1 (SRPK1), a key regulator of splicing factor phosphorylation, has emerged as a potential therapeutic target. This study aimed to identify and evaluate splicing patterns in cervical cancer in response to SRPK1 inhibition. Materials and Methods: HeLa (HPV18⁺), SiHa (HPV16⁺), and C33A (HPV⁻) cervical cancer cell lines were treated with the SRPK1 inhibitor SPHINX31 (0.3-10 μM). Cell viability was assessed using the Alamar Blue assay, while cell cycle progression and apoptosis were evaluated by flow cytometry using fluorescence-activated cell sorting (FACS) and Annexin V/propidium iodide staining. Transcriptomic profiling was performed by RNA sequencing to identify differentially expressed genes and alternative splicing (AS) events, followed by pathway enrichment and protein-protein interaction (PPI)/MCODE network analyses. Molecular docking was used to assess the binding of SPHINX31 within the SRPK1 ATP pocket. Results and Discussion: Treatment of cervical cancer cells with SPHINX31 resulted in a non-significant cellular response, with no effect on cell viability, cell cycle progression, or induction of apoptosis. In HPV-negative C33A cells, SRPK1 inhibition upregulated genes involved in translation, RNA processing, and glycosylation, which revealed ribosomal network hubs suggesting possible translational and metabolic adaptation. C33A also displayed skipped exon (SE) and retained intron (RI) events along with alternative 5' splice site (A5SS) alterations. In contrast, HPV16⁺ SiHa cells exhibited downregulation of oncogenic signalling pathways, including Hippo, Wnt, PI3K-AKT, and ERK1/2. SiHa exhibited fewer overall AS events but with greater effect sizes. Molecular docking analyses supported a computationally predicted binding. Conclusion: This study provides insight into the effects of SRPK1 inhibition on cellular response, splicing patterns, and the transcriptomic landscape. Overall, SRPK1 inhibition in CCa may induce changes that differ according to HPV status, with HPV⁺ cells exhibiting vulnerability, while HPV⁻ cells may display a possible metabolic adaptation.