Abstract 6680: Androgen-regulated miRNA-mRNA interactions in luminal A breast cancer: Insights into metastasis, anoikis resistance, and metabolic pathways

Abstract Background: Luminal A breast cancer (BC), the most common subtype of BC, often expresses the androgen receptor. This study explores androgen-regulated miRNA-mRNA interactions and their roles in metastasis, anoikis resistance, and metabolism. Methods: Luminal A cell lines, MCF-7 and T47D, and the luminal androgen receptor (LAR) MDA-MB-453 cells, were treated with dihydrotestosterone for 48 hrs, followed by microarray analysis of mRNA and miRNA expression. Expression data were normalized and differentially expressed (DE) transcripts were identified. Gene Set Enrichment Analysis was utilized, and miRNA-mRNA interaction networks were built using multiMiR. Survival analyses, coexpression, and therapy response comparisons were done on luminal A cohorts in TCGA, 'ROC Plotter', and ‘KMplotter’. MAVISTO's algorithm was used for network motif discovery. Results: Seven DEmiRNAs were found in MCF-7 cells and 20 in T47D, both of which were fewer than the 66 found in LAR. A 17-gene androgen response signature was derived by overlapping DEmiRNA-targeted DEmRNAs in luminal A cells with the 'Hallmark Androgen Response' set, including 16 upregulated mRNAs like FKBP5, a hub mRNA regulated by hsa-miR-429, and TPD52, both of which were in T47D and MCF-7. The mean expression of the signature correlated with better overall survival (OS) in luminal A BC (HR = 0.67, 95% CI: 0.45-0.99, n = 1,504) and was higher in endocrine therapy responders compared with non-responders (p = 0.041). However, only three genes in the signature had significant negative epithelial-mesenchymal transition (EMT) scores, while 11 were EMT-promoting. Bi-fan network motifs in signature-related network, featuring two miRNAs co-regulating two mRNAs, were the most enriched. Negative regulation of anoikis, an enriched term, had two upregulated EMT-promoting genes, SNAI2 and CAV1 in MCF-7, both with significant coexpression with downregulated hsa-miR-429 (correlations ≤ -0.29); DEmRNA signature from this term predicted poor OS (HR = 1.8, p = 0.038). Syndecan-mediated signaling was enriched, with SDC2 upregulated and interacting with the downregulated miRNAs hsa-miR-429, hsa-miR-4490, and hsa-miR-890 upon androgen treatment. Similarly, RND3 GTPase was upregulated and interacted with hsa-miR-429. Syndecan and RND3, linked to metastasis, may share a regulatory pathway. Insulin signaling was also enriched; Insulin Receptor Substrate 1 (IRS1) was downregulated and interacted with hsa-miR-429 and hsa-miR-890. In T47D, estrogen response, linked to DEmRNAs FKBP5 and FASN, and previously related to invasion and anoikis resistance, emerged as a key enriched term from miRNA-regulated mRNAs. Conclusion: We found significant androgen-regulated miRNA-mRNA interactions influencing anoikis suppression, metastasis, and metabolic shifts in luminal A breast cancer, with hsa-miR-429 as a key regulator. Citation Format: Jehad A. Yasin, Osama M. Younis, Leen A. AlKuttob, Ramez M. Odat, Sofia Adwan, Mohammad Abdulla, Afaf Mansour, Dana Alsafadi, Mamoun Ahram. Androgen-regulated miRNA-mRNA interactions in luminal A breast cancer: Insights into metastasis, anoikis resistance, and metabolic pathways [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 6680.