No abstract

PIWI-interacting RNAs (piRNAs) are small noncoding RNAs that play important roles in germline development and carcinogenesis. In this study, we used the deep sequencing of small RNA Transcriptome to explore the piRNA expression in six clear cell renal carcinoma (ccRCC) tissues and matched adjacent normal tissues and found that six piRNAs were upregulated and sixteen were downregulated in ccRCC tissues. Among them, piRNA-31115 (NCBI accession number: DQ571003) was the most upregulated piRNA in ccRCC tissues compared with matched adjacent normal tissues. Quantitative real-time PCR (qRT-PCR) was used to confirm piR-31115 expression in other ccRCC tissues ( n = 40 ) and ccRCC cell lines. Besides, function analysis demonstrated that silencing of piR-31115 inhibited ccRCC cell proliferation, motility, and invasiveness. Mechanistic investigations showed that piRNA-31115 may activate epithelial-mesenchymal transition (EMT) via the PI3K/AKT signaling pathway. Hence, piR-31115 may represent an oncogene in the development of ccRCC.

As one of the most common cancer chemotherapy drugs, cisplatin is widely used in cancer management. However, cisplatin-induced nephrotoxicity occurs in patients who receive this drug. This study is aimed at developing therapeutic agents that effectively alleviate the nephrotoxic effects during cisplatin treatment. We identified a compound named pyrocatechol (PCL) from a natural product library that significantly alleviated cisplatin-induced cytotoxicity in vitro. Pyrocatechol treatment substantially ameliorated cisplatin (20 mg · kg-1) treatment-induced neuropathological indexes, including inflammatory cell infiltration and apoptosis, in vivo. Mechanistically, pyrocatechol significantly prevented oxidative stress-induced apoptosis by activating glutathione peroxidase 4 (GPX4) to reduce reactive oxygen species (ROS) accumulation in cisplatin-treated cells. In addition, pyrocatechol significantly inhibited ROS-induced JNK/P38 activation. Thus, we found that pyrocatechol prevents ROS-mediated JNK/P38 MAPK activation, apoptosis, and cytotoxicity through GPX4. Our study demonstrated that pyrocatechol is a novel therapeutic agent against cisplatin-induced kidney injury.

Circular RNAs (circRNAs), a novel class of noncoding RNAs, have been shown to play critical regulatory roles in clear cell renal cell carcinoma (ccRCC). Metastasis is the main contributor to the poor prognosis of patients with ccRCC. However, the role of circRNAs in ccRCC metastasis has not been fully elucidated. In this study, microarray and RNA-seq analyses revealed that circPSD3 (hsa_circ_0002111) was dramatically downregulated in ccRCC tissues compared to adjacent nontumor tissues. A qRT-PCR analysis performed on our ccRCC cohorts confirmed the downregulation of circPSD3 in ccRCC tissues and further suggested that a low level of circPSD3 expression was associated with tumor metastasis in patients with ccRCC. Based on the results of functional studies, circPSD3 significantly inhibited cell migration, invasion, and the epithelial-mesenchymal transition (EMT) in vitro and blocked pulmonary metastasis in vivo. Mechanistically, circPSD3 functioned as a competing endogenous RNA for microRNA 25-3p (miR-25-3p) to regulate F-box and WD repeat domain-containing 7 (FBXW7) expression. Further verification indicated that circPSD3 overexpression restrained an EMT-like phenotype in cells, while miR-25-3p partially rescued these effects. In summary, circPSD3 inhibits tumor metastasis by repressing the miR-25-3p/FBXW7-EMT axis and might be developed as a potential diagnostic and therapeutic target for ccRCC.

Background. Clear cell renal cell carcinoma (ccRCC) is one of the most lethal malignancies in the urinary system, yet effective diagnostic and prognostic markers are lacking. Recently, several of piRNA pathway genes have been reported to be associated with cancer diagnosis and prognosis, but their role in ccRCC is still unclear. Methods. We analysed the expression of 27 piRNA pathway genes in 539 kidney renal clear cell carcinoma (KIRC) and 72 nontumor tissue samples (data from TCGA), and 12 mRNAs were significantly different. The aim was to sift the piRNA pathway genes that are correlated with ccRCC patient survival and to construct a piRNA pathway gene risk prognostic model using Kaplan-Meier survival curve and ROC curve, respectively. Results. 5 piRNA pathway genes (TDRD7, GPAT2, PLD6, SUV39H1, and DOM3Z) were picked out and used to construct the piRNA pathway gene risk model. Kaplan-Meier survival curve analysis showed that compared with that of the low-risk group of ccRCC patients, the OS of the high-risk group of ccRCC patients was significantly reduced. The predictive performance of the prognostic risk model was measured using a ROC curve, which individually showed AUC values for 1 year of 0.707, for 3 years of 0.713, and for 5 years of 0.701. Moreover, the mRNA and protein expression levels of TDRD7 were overexpressed in the ccRCC datasets (data from our cohort, TCGA, GEO, and CPTAC) and ccRCC cell lines, and the expression levels correlated with the clinicopathological characteristics in ccRCC. The Tumor Immune Estimation Resource (TIMER) showed that the mRNA expression level of TDRD7 was positively related to tumor immune infiltrating cells (TICs) in ccRCC. Mechanistically, gene set enrichment analysis (GSEA) was performed to uncover the mechanism of TDRD7 in ccRCC. In summary, the piRNA pathway genes,especially TDRD7, may be potential cancer diagnostic and prognostic biomarkers of ccRCC.