Long noncoding RNAs (lncRNAs) are implicated in renal cell carcinoma (RCC), but remain largely unclear. Using publicly available transcriptome sequencing data from renal cancer (n = 703) and integrating bioinformatics analyses, we screened and identified a valuable lncRNA, EGFR-AS1. In our validation cohort (n = 204), EGFR-AS1 was significantly upregulated in RCC tissues (P < 0.001). Gain-of-function and loss-of-function studies showed that EGFR-AS1 promoted cell proliferation and invasion in vitro and in vivo. Based on previous studies and sequence complementarity of EGFR with EGFR-AS1, we demonstrated that EGFR-AS1 directly bound to EGFR mRNA and inhibited its degradation. Furthermore, RNA pull-down and mass spectrometry analyses showed that EGFR-AS1 interacted with HuR, which was responsible for the mRNA stability of EGFR. Multivariate analysis suggested that higher EGFR-AS1 expression predicted a poor prognosis in RCC patients (high vs low: P = 0.018, HR = 2.204, 95% CI: 1.145–4.241). In conclusion, EGFR-AS1 enhances the malignant phenotype of RCC cells by enhancing HuR-mediated mRNA stability of EGFR. Our data also provide biological rationales for EGFR-AS1 as a prognostic biomarker and a potential therapeutic target for RCC.
Rationale: Although sunitinib has been shown to improve the survival rate of advanced renal cell carcinoma (RCC) patients, poor drug response is a major challenge that reduces patient benefit. It is important to elucidate the underlying mechanism so that the therapeutic response to sunitinib can be restored.Methods: We used an Illumina HumanMethylation 850K microarray to find methylation-differentiated CpG sites between sunitinib-nonresponsive and -responsive RCC tissues and Sequenom MassARRAY methylation analysis to verify the methylation chip results. We verified glutaminyl peptide cyclotransferase (QPCT) expression in sunitinib-nonresponsive and -responsive RCC tissues via qRT-PCR, western blot and immunohistochemical assays. Then, cell counting kit 8 (CCK-8), plate colony formation and flow cytometric assays were used to verify the function of QPCT in RCC sunitinib resistance after QPCT intervention or overexpression. Chromatin immunoprecipitation (ChIP) was performed to clarify the upstream regulatory mechanism of QPCT. A human proteome microarray assay was used to identify downstream proteins that interact with QPCT, and co-immunoprecipitation (co-IP) and confocal laser microscopy were used to verify the protein chip results.Results: We found that the degree of methylation in the QPCT promoter region was significantly different between sunitinib-nonresponsive and -responsive RCC tissues. In the sunitinib-nonresponsive tissues, the degree of methylation in the QPCT promoter region was significantly reduced, and the expression of QPCT was upregulated, which correlated with a clinically poor response to sunitinib. A knockdown of QPCT conferred sunitinib sensitivity traits to RCC cells, whereas an overexpression of QPCT restored sunitinib resistance in RCC cells. Mechanistically, reducing the methylation degree of the QPCT promoter region by 5-aza-2'-deoxycytidine (decitabine) in RCC cells could increase the expression of QPCT and NF-κB (p65) bound to the QPCT promoter region, positively regulating its expression, while the hypermethylation in the QPCT promoter region could inhibit the binding of NF-κB (p65). QPCT could bind to HRAS and attenuate the ubiquitination of HRAS, thus increasing its stability and leading to the activation of the ERK pathway in RCC cells.Conclusion: QPCT may be a novel predictor of the response to sunitinib therapy in RCC patients and a potential therapeutic target.
Accumulating evidence indicates that eukaryotic translation elongation factor 1 alpha 1 (eEF1A1) is involved in cancer, while the clinical significance and the exact role of eEF1A1 in renal cell carcinoma (RCC) remain obscure. The aim of the present study was to evaluate the clinical significance of eEF1A1 in RCC and to investigate its effective mechanisms in order to identify a potential therapeutic target. The expression levels of eEF1A1 in RCC were explored by immunohistochemistry in tissues from 184 patients. eEF1A1 was knocked down, and cell proliferation and apoptosis were then investigated. The MAPK pathway-related proteins were detected by western blot. Our results revealed that eEF1A1 was highly expressed in RCC tissues and associated with poor prognosis. Knockdown of eEF1A1 attenuated proliferation and promoted the apoptosis of RCC cells. Furthermore, eEF1A1 knockdown decreased the phosphorylation level of AKT and ERK. In conclusion, eEF1A1 may serve as a valuable prognostic biomarker and promising therapeutic target of RCC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.