RNA sequencing and bioinformatics analysis revealed PACSIN3 as a potential novel biomarker for platinum resistance in epithelial ovarian cancer

Background: Failure to respond to treatment in epithelial ovarian cancer can often be attributed to platinum-based chemotherapy resistance. However, the possible mechanisms or candidate biomarkers associated with platinum resistance are yet to be elucidated, even though many researchers have performed related studies. Methods: We performed RNA sequencing of clinical specimens obtained from patients with platinum-sensitive or resistant epithelial ovarian cancer (EOC). Furthermore, various bioinformatics approaches, including spatial analysis of functional enrichment, were used to identify key regulators and associated underlying mechanisms of platinum resistance in EOC. Results: Through RNA-sequencing, we identified 263 differentially expressed genes (98 upregulated and 165 downregulated) and subjected them to Gene Oncology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, which were characterized to the traditional platinum-resistant characteristics. Subsequently, the gene interaction network and module analysis by spatial analysis of functional enrichment software demonstrated protein kinase C and casein kinase substrate in neurons 3 (PACSIN3) as the only upregulated hub gene, and neurotensin (NTS) and KIAA0319 as downregulated hub genes in platinum-resistant EOC. We selected PACSIN3 for further analysis because it has not been studied in relation to response to platinum-based chemotherapy. PACSIN3 was significantly upregulated in ovarian cancer cells compared to immortalized human ovarian surface epithelial cells. In addition, cisplatin-induced apoptosis was measured in PACSIN3 knockout OVCA433 and BRCA-mutated EOC cell line, SNU251, by a fluorescence-activated cell sorting-based Annexin-V/propium iodide double staining assay, which revealed a significant increase in apoptosis. Conclusions: Taken together, the present study presents PACSIN3 as a promising predictive biomarker associated with platinum resistance, especially in BRCA-mutated epithelial ovarian cancersrestrictio