Poster abstracts
Poster number 86 submitted by Zac LaRocca-Stravalle
Unveiling the Alternative Splicing Landscape in Hepatoblastoma: Enhancing Prognostic and Therapeutic Approaches
Zac LaRocca-Stravalle (Center for Childhood Cancer at Nationwide Childrens Hospital), Safiya Khurshid (Center for Childhood Cancer at Nationwide Childrens Hospital), Dawn Chandler (Center for Childhood Cancer at Nationwide Childrens Hospital)
Abstract:
Objectives
Hepatoblastoma (HB), the most common pediatric liver cancer, has a 3-year event-free survival rate above 80% with chemotherapy and surgery, yet outcomes for advanced tumors remain poor. While molecular stratifications based on genomic, transcriptomic, and epigenomic data have been proposed to predict prognosis, the alternative splicing (AS) landscape in HB remains unexplored. Since pediatric cancers, including HB, typically have a low mutational burden but are enriched for AS events, investigating AS could reveal new biomarkers and therapeutic targets.
Methods
We used RNA-sequencing data from 30 matched tumor-normal HB patients (GEO: GSE133039) to perform differential splicing analysis with rMATS. Significant genes were further analyzed using R, and unsupervised hierarchical clustering of patients and their PSI values was conducted with correlation distanced. Differential gene expression was assessed using edgeR, and key AS events were validated in HepG2 cells and normal tissue using RT-PCR.
Results
We identified 1,876 significant AS events, including 55% skipped exons (SE), 8% retained introns, 24% mutually exclusive exons, 6% alternative 5’ splice sites, and 7% alternative 3’ splice sites. Hierarchical clustering revealed two tumor subgroups. One cluster, comprising 5 out of 30 patients, was characterized by the skipping of exon 11 in INSR, which is linked to tumor growth and angiogenesis. This cluster also exhibited elevated levels of splicing factors CELF5, PTBP1, and FUS, while the other cluster showed upregulation of MBNL1, MBNL2, and CELF2.
Conclusion
These findings suggest that HB tumors can be stratified based on AS profiles, with distinct tumor clusters showing differential splicing factor expression. Further research is needed to explore the clinical implications of these clusters, including associations with metastasis, PRETEXT stage, histology, and survival. This study opens new pathways for the molecular characterization of HB, providing insights into AS mechanisms that could lead to novel biomarkers and therapies.
References:
Carrillo-Reixach, J., et al. (2020). Epigenetic footprint enables molecular risk stratification of hepatoblastoma with clinical implications. Journal of Hepatology, 73(2), 328–341. https://doi.org/10.1016/j.jhep.2020.03.025
Hooks, K. B., et al. (2018). New insights into diagnosis and therapeutic options for proliferative hepatoblastoma. Hepatology, 68(1), 89–102. https://doi.org/10.1002/hep.29672
Venkataramany, A.S., et al. (2022). Alternative RNA splicing defects in pediatric cancers: New insights in tumorigenesis and potential therapeutic vulnerabilities. Annals of Oncology, 33(6), 578–592. https://doi.org/10.1016/j.annonc.2022.03.011
Keywords: Alternative Splicing , Hepatoblastoma , RNA therapeutics