Abstract P1-07-20: Mechanism of miR-221-3p/PARP1 regulating the progression of triple-negative breast cancer through the NF-κB pathway

Abstract Purpose: The underlying mechanisms driving the occurrence and progression of triple-negative breast cancer (TNBC) necessitate comprehensive elucidation. Our previous findings have demonstrated a significant association between low expression of miR-221-3p and unfavorable prognosis in TNBC patients, wherein it exerts inhibitory effects on TNBC cell proliferation and metastasis by negatively regulating PARP1. Prior studies have suggested that PARP1 facilitates TNBC progression through modulation of the NF-κB pathway. This study aims to elucidate the role of the miR-221-3p/PARP1/NF-κB axis in TNBC progression. Materials and Methods: We established MDA-MB-231 cell lines with either overexpression or downregulation of PARP1 by plasmid transfection. Transcriptome sequencing and KEGG(Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis were employed to identify differentially expressed genes and associated signaling pathways in the various cell lines. The effect of PARP1 on the expression of NF-κB pathway-related molecules was validated through analysis using the TCGA (The Cancer Genome Atlas) database, Real-time PCR(Polymerase Chain Reaction), and Western blot techniques. Additionally, miR-221-3p modulation by miRNA mimic or inhibitor was performed to elucidate its role in regulating the NF-κB pathway via targeting PARP1. Cell proliferation and migration abilities in TNBC cells were assessed using CCK8 assay and Transwell chamber. Results: KEGG pathway enrichment analysis revealed significant alterations in the expression of molecules related to the NF-κB signaling pathway between cell lines with differential PARP1 expression. Subsequent analysis of the TCGA database demonstrated that high expression of NF-κB signaling pathway-related molecules, particularly the NFKB1 gene, was predominantly enriched in cells overexpressing PARP1. In vitro experiments confirmed a substantial increase in both NFKB1 gene and protein levels in PARP1-overexpressing cells compared to the control group. In contrast, the knockdown of PARP1 exerted an opposite effect, thus establishing a positive correlation between PARP1 and NFKB1. Additionally, miR-221-3p exhibited a negative correlation with NFKB1. Furthermore, we observed that downregulation of PARP1 attenuated the regulatory effect of miR-221-3p on NFKB1 and improved outcomes for TNBC. In contrast, the upregulation of PARP1 exerted an opposite effect. Conclusion: PARP1 exhibits a positive correlation with NFKB1, while miR-221-3p demonstrates a negative correlation with NFKB1. The regulatory role of miR-221-3p in TNBC proliferation and migration, as well as the modulation of NFKB1 expression, is mediated through its targeting of PARP1. The miR-221-3p/PARP1/NFKB1 axis plays a crucial role in regulating the progression of TNBC cells. Citation Format: Qianqian Lei, Ye Hong, Kegui Weng, Yanyan Long, Min Ying, Jing Chen, Mengyu Hu, Deqing Liu. Mechanism of miR-221-3p/PARP1 regulating the progression of triple-negative breast cancer through the NF-κB pathway [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P1-07-20.