Molecular insights into uterine fibroids: crosstalk between SHH and Wnt pathways, DNA methylation, and miRNAs regulation.

Uterine leiomyomas (ULMs) are the most common benign gynecological tumors affecting women in reproductive age. Symptoms such as abnormal uterine bleeding, pelvic pain, and infertility may occur, leading to a significant decline in patients' quality of life. In addition, ULMs represent the second leading indication for gynecological surgery in Brazil, imposing a substantial economic burden on the public healthcare system. However, despite their high prevalence and clinical impact, there is still no curative clinical treatment for these tumors, and the molecular mechanisms underlying their development and clinical behavior remain poorly understood. Recent studies have demonstrated the involvement of the Sonic Hedgehog (SHH) signaling pathway in uterine mesenchymal tumors. Therefore, the aim of this study was to investigate the expression profile and regulation of the SHH and Wnt signaling pathways in ULMs, as well as to evaluate their potential role in tumor progression through integrative analyses of promoter methylation, mRNA expression, and microRNA-mediated regulation. Initially, 106 genes related to SHH, Wnt signaling pathways were examined in ULM, compared to normal myometrium (MM) by real-time PCR. Interactions among SHH pathway genes were assessed through multivariate analysis. In addition, methylation profiles of nine key SHH-related genes were evaluated using methylation-specific assays, and the expression of 84 microRNAs (miRNAs) was analyzed in association with differentially expressed genes potentially involved in tumorigenesis. Differential expression analysis identified 23 dysregulated genes, including 13 upregulated and 10 downregulated genes. Multivariate analysis suggested that SHH pathway activation in ULMs occurs independently of SHH-PTCH1 binding and may involve GLI1, CCND1, and BCL-2. Significant DNA methylation alterations were detected in PTCH1, SMO, GLI1, GLI3, GREM1, and WNT1. Furthermore, 16 miRNAs were differentially expressed, eight of which showed significant correlations with their predicted target genes. Collectively, these findings suggest that ULM pathogenesis involves a complex regulatory network integrating SHH and Wnt signaling pathways, epigenetic modifications, and microRNA-mediated post-transcriptional regulation. These results provide novel insights into the molecular mechanisms underlying ULM development and identify candidate regulatory elements that may serve as potential biomarkers or therapeutic targets in future functional studies on uterine fibroids.