piR-1919609 Is an Ideal Potential Target for Reversing Platinum Resistance in Ovarian Cancer.

PURPOSE: PIWI-interacting RNAs (piRNAs) are a type of noncoding small RNA that can interact with PIWI-like RNA-mediated gene silencing (PIWIL) proteins to affect biological processes such as transposon silencing through epigenetic effects. Recent studies have found that piRNAs are widely dysregulated in tumors and associated with tumor progression and a poor prognosis. Therefore, this study aimed to investigate the effect of piR-1919609 on the proliferation, apoptosis, and drug resistance of ovarian cancer cells. METHODS: In this study, we used small RNA sequencing to screen and identify differentially expressed piRNAs in primary ovarian cancer, recurrent ovarian cancer, and normal ovaries. A large-scale verification study was performed to verify the expression of piR-1919609 in different types of ovarian tissue, including ovarian cancer tissue and normal ovaries, by RT-PCR and to analyze its association with the clinical prognosis of ovarian cancer. The expression of PIWILs in ovarian cancer was verified by RT-PCR, Western blotting and immunofluorescence. The effects of piR-1919609 on ovarian cancer cell proliferation, apoptosis and drug resistance were studied through in vitro and in vivo models. RESULTS: (1) piR-1919609 was highly expressed in platinum-resistant ovarian cancer tissues (p < 0.05), and this upregulation was significantly associated with a poor prognosis and a shorter recurrence time in ovarian cancer patients (p < 0.05). (2) PIWIL2 was strongly expressed in ovarian cancer tissues (p < 0.05). It was expressed both in the cytoplasm and nucleus of ovarian cancer cells. (3) Overexpression of piR-1919609 promoted ovarian cancer cell proliferation, inhibited apoptosis, and promoted tumor growth in nude mice. (4) Inhibition of piR-1919609 effectively reversed ovarian cancer drug resistance. CONCLUSION: In summary, we showed that piR-1919609 is involved in the regulation of drug resistance in ovarian cancer cells and might be an ideal potential target for reversing platinum resistance in ovarian cancer.

ARRDC3 as a Diagnostic and Prognostic Biomarker for Epithelial Ovarian Cancer Based on Data Mining.

PURPOSE: The dysregulation of arrestin domain containing 3 (ARRDC3) has an important effect on oncogenesis and tumor progression in many cancers, including renal cell carcinoma and breast cancer. However, the role of ARRDC3 in ovarian cancer (OC) has not been reported. METHODS: The present study explored the diagnostic and prognostic roles of ARRDC3 in ovarian cancer using GEPIA, ONCOMINE, GEO, and Kaplan-Meier Plotter databases for training and validation. Then, we conducted a stratified analysis for clinicopathological factors using Kaplan-Meier Plotter and GEPIA databases. To further explore the mechanisms, we also used the MIST database to visualize the protein-protein interaction network of ARRDC3 associated with OC. The gene-gene interaction network was visualized by GeneMANIA plugin in Cytoscape 3.8.0 software, and the associated co-expression genes of ARRDC3 were analyzed by the cBioPortal database. The 100 top co-expression genes chosen for gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used by the DAVID website. RESULTS: A significant difference in ARRDC3 mRNA expression was found between OC and normal ovary tissues. ARRDC3 could potentially be implicated in the diagnosis of OC. A high ARRDC3 mRNA expression level was associated with poor overall survival and progression-free survival. However, no significance was reported in respect to post progression survival. Except for histology, which had no prognostic value for PPS in stratified analysis, stratified analysis of other factors had prognostic value for OS, PFS, and PPS. Interestingly, we found a positive correlation between ARRDC3 expression and CD8+ T cells, macrophages, neutrophils, and dendritic cells, indicating that ARRDC3 might be associated with immune infiltration of these immune cells. Co-expression genes enrichment analysis found that they were involved in the Renin-angiotensin system pathway. CONCLUSION: Differentially expressed ARRDC3 might be a potential prognostic and diagnostic marker in Ovarian Cancer.