The prognostic value of miRNA-18a-5p in clear cell renal cell carcinoma and its function via the miRNA-18a-5p/HIF1A/PVT1 pathway

Regulation of the HIF switch in human endothelial and cancer cells

Hypoxia-inducible factors (HIFs) are transcription factors that reprogram the transcriptome for cells to survive hypoxic insults and oxidative stress. They are important during embryonic development and reprogram the cells to utilize glycolysis when the oxygen levels are extremely low. This metabolic change facilitates normal cell survival as well as cancer cell survival. The key feature in survival is the transition between acute hypoxia and chronic hypoxia, and this is regulated by the transition between HIF-1 expression and HIF-2/HIF-3 expression. This transition is observed in many human cancers and endothelial cells and referred to as the HIF Switch. Here we discuss the mechanisms involved in the HIF Switch in human endothelial and cancer cells which include mRNA and protein levels of the alpha chains of the HIFs. A major continuing effort in this field is directed towards determining the differences between normal and tumor cell utilization of this important pathway, and how this could lead to potential therapeutic approaches.

MicroRNA Expression Signatures in Clear Cell Renal Cell Carcinoma: High-Throughput Searching for Key miRNA Markers in Patients from the Volga-Ural Region of Eurasian Continent

Clear cell renal cell carcinoma (ccRCC) is characterized by high molecular genetic heterogeneity, metastatic activity and unfavorable prognosis. MicroRNAs (miRNA) are 22-nucleotide noncoding RNAs that are aberrantly expressed in cancer cells and have gained serious consideration as non-invasive cancer biomarkers. We investigated possible differential miRNA signatures that may differentiate high-grade ccRCC from primary disease stages. High-throughput miRNAs expression profiling, using TaqMan OpenArray Human MicroRNA panel, was performed in a group of 21 ccRCC patients. The obtained data was validated in 47 ccRCC patients. We identified nine dysregulated miRNAs (miRNA-210, -642, -18a, -483-5p, -455-3p, -487b, -582-3p, -199b and -200c) in tumor ccRCC tissue compared to normal renal parenchyma. Our results show that the combination of miRNA-210, miRNA-483-5p, miRNA-455 and miRNA-200c is able to distinguish low and high TNM ccRCC stages. Additionally, miRNA-18a, -210, -483-5p and -642 showed statistically significant differences between the low stage tumor ccRCC tissue and normal renal tissue. Contrariwise, the high stages of the tumor process were accompanied by alteration in the expression levels of miRNA-200c, -455-3p and -582-3p. Although the biological roles of these miRNAs in ccRCC are not totally clear, our findings need additional investigations into their involvement in the pathogenesis of ccRCC. Prospective studies with large study cohorts of ccRCC patients are important to further establish the clinical validity of our miRNA markers to predict ccRCC.

An Integrative Analysis Framework for Identifying the Prognostic Markers from Multidimensional RNA Data of Clear Cell Renal Cell Carcinoma

The altered regulatory status of long noncoding RNA (lncRNA), miRNA, and mRNA and their interactions play critical roles in tumor proliferation, metastasis, and progression, which ultimately influence cancer prognosis. However, there are limited studies of comprehensive identification of prognostic biomarkers from combined data sets of the three RNA types in the highly metastatic clear cell renal cell carcinoma (ccRCC). The current study employed an integrative analysis framework of functional genomics approaches and machine learning methods to the lncRNA, miRNA, and mRNA data and identified 16 RNAs (3 lncRNAs, 6 miRNAs, and 7 mRNAs) of prognostic value, with 9 of them novel. A 16 RNA-based score was established for prognosis prediction of ccRCC with significance (P < 0.0001). The area under the curve for the score model was 0.868 to 0.870 in the training cohort and 0.714 to 0.778 in the validation cohort. Construction of the lncRNA-miRNA-mRNA interaction network showed that the downstream mRNAs and upstream lncRNAs in the network initiated from the miRNA or lncRNA markers exhibit significant enrichment in functional classifications associated with cancer metastasis, proliferation, progression, or prognosis. The functional analysis provided clear support for the role of the RNA biomarkers in predicting cancer prognosis. This study provides promising biomarkers for predicting prognosis of ccRCC using multidimensional RNA data, and these findings are expected to facilitate potential clinical applications of the biomarkers.

MicroRNA as a Biomarker for Diagnostic, Prognostic, and Therapeutic Purpose in Urinary Tract Cancer

The incidence of urologic cancers, including kidney, upper tract urothelial, and bladder malignancies, is increasing globally, with a high percentage of cases showing metastasis upon diagnosis and low five-year survival rates. MicroRNA (miRNA), a small non-coding RNA, was found to regulate the expression of oncogenes and tumor suppressor genes in several tumors, including cancers of the urinary system. In the current review, we comprehensively discuss the recently reported up-or down-regulated miRNAs as well as their possible targets and regulated pathways involved in the development, progression, and metastasis of urinary tract cancers. These miRNAs represent potential therapeutic targets and diagnostic/prognostic biomarkers that may help in efficient and early diagnosis in addition to better treatment outcomes.

Testicular Nuclear Receptor 4 Regulates Proliferation and Apoptosis of Bladder Cancer via Bcl-2

Testicular nuclear receptor 4 (TR4) is a member of the nuclear hormone receptor family and acts as a ligand-activated transcription factor and functions in many biological processes, such as development, cellular differentiation, and homeostasis. Recent studies have shown that TR4 plays an important role in prostate cancer, renal cell carcinoma, and hepatocellular carcinoma; however, its potential link to bladder cancer (BC) remains unknown. This study found that bladder cancer exhibited a higher expression of TR4 compared to normal tissues. Overexpressed TR4 promoted the bladder cancer cell proliferation, and knocked down TR4 with TR4-siRNA suppressed the bladder cancer cell proliferation. Mechanistic studies reveal that TR4 functions by altering the expression of Bcl-2 to regulate apoptosis in bladder cancer cells. Furthermore, knocking down Bcl-2 reversed the BC proliferation induced by TR4. In vivo, we also confirmed that TR4 knockdown mice (TR4^+/−) showed slower bladder cancer growth than wild-type mice (TR4^+/+) induced by the carcinogenic chemicals. Moreover, TR4^+/− mice showed a lower grade of histopathology than the control group. In conclusion, these results indicate that TR4 plays a key role in bladder cancer proliferation, and targeting TR4 would probably be a potential strategy for bladder cancer treatment.

Positive feedback regulation of lncRNA PVT1 and HIF2α contributes to clear cell renal cell carcinoma tumorigenesis and metastasis

Long noncoding RNAs (lncRNAs) have been reported to exert important roles in tumors, including clear cell renal cell carcinoma (ccRCC). PVT1 is an important oncogenic lncRNA which has critical effects on onset and development of various cancers, however, the underlying mechanism of PVT1 functioning in ccRCC remains largely unknown. VHL deficiency-induced HIF2α accumulation is one of the major factors for ccRCC. Here, we identified the potential molecular mechanism of PVT1 in promoting ccRCC development by stabilizing HIF2α. PVT1 was significantly upregulated in ccRCC tissues and high PVT1 expression was associated with poor prognosis of ccRCC patients. Both gain-of-function and loss-of function experiments revealed that PVT1 enhanced ccRCC cells proliferation, migration, and invasion and induced tumor angiogenesis in vitro and in vivo. Mechanistically, PVT1 interacted with HIF2α protein and enhanced its stability by protecting it from ubiquitination-dependent degradation, thereby exerting its biological significance. Meanwhile, HIF2α bound to the enhancer of PVT1 to transactivate its expression. Furthermore, HIF2α specific inhibitor could repress PVT1 expression and its oncogenic functions. Therefore, our study demonstrates that the PVT1/ HIF2α positive feedback loop involves in tumorigenesis and progression of ccRCC, which may be exploited for anticancer therapy.

lncRNA PVT1 in the Pathogenesis and Clinical Management of Renal Cell Carcinoma

LncRNA PVT1 (plasmacytoma variant translocation 1) has become a staple of the lncRNA profile in patients with renal cell carcinoma (RCC). Common dysregulation in renal tumors outlines the essential role of PVT1 in the development of RCC. There is already a plethora of publications trying to uncover the cellular mechanisms of PVT1-mediated regulation and its potential exploitation in management of RCC. In this review, we summarize the literature focused on PVT1 in RCC and aim to synthesize the current knowledge on its role in the cells of the kidney. Further, we provide an overview of the lncRNA profiling studies that have identified a more or less significant association of PVT1 with the clinical behavior of RCC. Based on our search, we analyzed the 17 scientific papers discussed in this review that provide robust support for the indispensable role of PVT1 in RCC development and future personalized therapy.

Dual miRNases for Triple Incision of miRNA Target: Design Concept and Catalytic Performance

Irreversible destruction of disease-associated regulatory RNA sequences offers exciting opportunities for safe and powerful therapeutic interventions against human pathophysiology. In 2017, for the first time we introduced miRNAses–miRNA-targeted conjugates of a catalytic peptide and oligonucleotide capable of cleaving an miRNA target. Herein, we report the development of Dual miRNases against oncogenic miR-21, miR-155, miR-17 and miR-18a, each containing the catalytic peptide placed in-between two short miRNA-targeted oligodeoxyribonucleotide recognition motifs. Substitution of adenines with 2-aminoadenines in the sequence of oligonucleotide “shoulders” of the Dual miRNase significantly enhanced the efficiency of hybridization with the miRNA target. It was shown that sequence-specific cleavage of the target by miRNase proceeded metal-independently at pH optimum 5.5–7.5 with an efficiency varying from 15% to 85%, depending on the miRNA sequence. A distinct advantage of the engineered nucleases is their ability to additionally recruit RNase H and cut miRNA at three different locations. Such cleavage proceeds at the central part by Dual miRNase, and at the 5′- and 3′-regions by RNase H, which significantly increases the efficiency of miRNA degradation. Due to increased activity at lowered pH Dual miRNases could provide an additional advantage in acidic tumor conditions and may be considered as efficient tumor-selective RNA-targeted therapeutic.

Knockdown of KRT17 decreases osteosarcoma cell proliferation and the Warburg effect via the AKT/mTOR/HIF1α pathway

Keratins are fibrous structural proteins that serve essential roles in forming the stratum corneum and protect the cells in this layer of skin from damage. Keratin 17 (KRT17) is a key member of the keratins, and dysregulated expression of KRT17 has been reported in various types of cancer, such as lung and gastric cancer. The present study aimed to identify the role of KRT17 in osteosarcoma and the underlying molecular mechanism. The expression of KRT17 in osteosarcoma tissues and cell lines was detected using reverse transcription‑quantitative PCR (RT‑qPCR) and western blotting. The effects of KRT17 on osteosarcoma cell proliferation and the Warburg effect in vitro were detected using CCK‑8 and colony formation assays, cell cycle distribution analysis and metabolic measures. The effects of KRT17 on osteosarcoma cell proliferation in vivo were detected using a subcutaneous tumorigenesis model. The association between KRT17 and the AKT/mTOR/hypoxia‑inducible factor 1α (HIF1α) pathway was detected using RT‑qPCR and western blotting. The results demonstrated that KRT17 was highly expressed in osteosarcoma tissues and cell lines. Knockdown of KRT17 decreased osteosarcoma cell proliferation and colony formation, induced G1 phase arrest and inhibited glycolysis in vitro. Similarly, the suppression of KRT17 decreased osteosarcoma tumor growth in vivo. Knockdown of KRT17 decreased the expression of phosphorylated (p)‑AKT, p‑mTOR, HIF1α and the target gene of HIF1α glucose transporter 1. Restoring the expression of p‑AKT, p‑mTOR or HIF1α reversed the effect of KRT17 inhibition on cell proliferation and glycolysis. These results indicated that knockdown of KRT17 may be an effective method for treating osteosarcoma through inhibiting osteosarcoma cell proliferation and the Warburg effect by suppressing the AKT/mTOR/HIF1α pathway.