Abstract 3039: Elucidating hsa_circ_0001038 and circRNA_400029 circular RNAs mechanisms in response to splicing factor 3 inhibitor in cervical cancer cells

Abstract Cervical cancer (CCa) is the fourth leading cause of cancer-related death among women worldwide. Around 90% of CCa cases are reported in low- and middle-income countries (LMICs), with Sub-Saharan Africa (SSA) bearing over 80% of the global burden. CircRNAs hsa_circ_0001038 and circRNA_400029 have been implicated in cervical cancer. Splicing factor 3 key a key factor in circRNA generation. However, mechanisms of these ceRNAs in CCa is poorly understood. This study aimed at elucidating hsa_circ_0001038 and circRNA_400029 mechanisms in response to splicing factor 3 inhibitor, theophylline in CCa. Using bioinformatics, CircAtlas, the study identified miRNA binding sites for hsa_circ_0001038, selecting miR-205-5p for further analysis due to its tumor-suppressive role. Similarly, miRTarBase predicted miR-16-5p as a key interacting miRNA for circRNA_400029. The downstream gene targets of these miRNAs were explored, focusing on those associated with CCa. Cell cycle FACS analysis and apoptosis assay were used to study cell biological response of theophylline to CCa cells SiHa and C33A. Furthermore, gene specific primers of hsa_circ_0001038, circRNA_400029 and SRSF3 were used to study gene expression in drug treated and control groups. Interestingly, ceRNA network was constructed, showing that one gene can be targeted by more than one miRNA. Additionally, pathway analysis using KEGG, STRING, and Reactome highlighted key signaling pathways, such as the HPV E5-EGFR-RAS-ERK and HPV E6-Notch pathways, which are implicated in cell proliferation, survival, and oncogenesis in CCa. Cell cycle analysis revealed G2/M arrest in response to theophylline treatment, while there was no significant cytotoxic effects of the drug, as revealed by apoptosis FACS analysis. hsa_circ_0001038, circRNA_400029 and SRSF3 were downregulated by theophylline treatment. Understanding circular RNAs and their interaction with splicing factors holds potential translational and clinical applications. Citation Format: Amahle Nyalambisa, Zodwa Dlamini, Rahaba Makgotso Marima. Elucidating hsa_circ_0001038 and circRNA_400029 circular RNAs mechanisms in response to splicing factor 3 inhibitor in cervical cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3039.