P-Element-Induced Wimpy Testis (PIWI)-Interacting RNA-823/PIWIL1/DNMT3B/CDH1 as Potential Axis to Drive EMT, Stemness, and Tumor Aggressiveness in Ovarian Cancer Tissue Samples: An Integrative Computational and Clinical Insights

Ovarian cancer (OC) remains the leading cause of death among gynecologic cancers. Most women diagnosed with OC at advanced stages eventually develop relapse and chemoresistance, leading to poor clinical outcomes. While piRNAs have emerged as critical regulators of gene expression and tumor biology, their specific roles in OC remain to be fully elucidated. This study integrated clinical and computational analyses to investigate the expression pattern and functional relevance of P-element-induced wimpy testis (PIWI)-interacting RNA-823 (piR-823) and its associated protein piwi-like RNA-mediated gene silencing 1 (PIWIL1)/DNA methyltransferase 3B (DNMT3B)/E-cadherin (CDH1) axis in OC tissues from 40 patients, with 20 non-cancer control samples. Expression profiling was performed using qPCR on OC and normal ovarian tissues, followed by correlation and regression analyses. Public databases, including GEPIA, TNM plot, and MethBank, were explored to validate gene expression, methylation status, and pathway enrichment. Our results revealed that piR-823, PIWIL1, and DNMT3B were significantly upregulated in OC tissues (<i>p</i> < 0.001, <i>p</i> = 0.009, and <i>p</i> < 0.001, respectively), and they correlated positively with each other and inversely with CDH1 expression. CDH2, OCT4, and NANOG were significantly upregulated (<i>p</i> = 0.011, <i>p</i> = 0.03, and <i>p</i> < 0.001, respectively), whereas CDH1 expression was significantly downregulated (<i>p</i> < 0.001) in OC tissues. In silico analyses supported DNMT3B-mediated CDH1 promoter methylation, epithelial-mesenchymal transition (EMT), and stemness pathway enrichment. Our integrated computational and clinical analyses indicate that the piR-823/PIWIL1/DNMT3B/CDH1 axis is a putative epigenetic regulator of EMT and cancer stemness in ovarian cancer. Additionally, piR-823 may serve as a promising prognostic biomarker and therapeutic target, offering novel insights into OC pathogenesis and treatment.