Identification of eight key miRNAs associated with renal cell carcinoma: A meta-analysis

miR-155-5p Promotes Cell Proliferation and Migration of Clear Cell Renal Cell Carcinoma by Targeting PEG3

OBJECTIVE

miR-155-5p as an important microRNA has been extensively studied for its biological functions and mechanisms in various cancers. However, the role and underlying mechanisms in clear cell renal cell carcinoma (ccRCC) remain to be further elucidated.

METHODS

Bioinformatics methods were implemented to analyze differentially expressed genes in the cancer genome atlas database. qRT-PCR and Western blot were employed to detect the expression of miR-155-5p and paternally expressed gene 3 (PEG3) mRNA as well as protein expression. Cell lines with miR-155-5p knockdown or miR-155-5p/PEG3 co-overexpression were constructed. A series of experiments including the MTT method, wound healing assay, and transwell assay were carried out to detect the proliferation, migration, and invasion of cancer cells in different treatment groups. Bioinformatics analysis and dual-luciferase assay were conducted to confirm the targeting relationship between PEG3 and miR-155-5p in ccRCC.

RESULTS

miR-155-5p was found to be significantly upregulated in ccRCC cells, while PEG3 exhibited significantly low expression. The downregulation of miR-155-5p could inhibit cell proliferation, migration, and invasion of ccRCC. miR-155-5p could inhibit the expression of PEG3. The overexpression of miR-155-5p could promote cell proliferation, migration, and invasion, whereas overexpression of PEG3 could significantly attenuate such effect. Therefore, miR-155-5p may promote cell growth of ccRCC via inhibiting PEG3 expression.

CONCLUSION

These findings validated the effect of miR-155-5p/PEG3 on ccRCC cells and provided novel potential targets for the prognosis and treatment of patients with ccRCC.

Identification of RCC Subtype-Specific microRNAs-Meta-Analysis of High-Throughput RCC Tumor microRNA Expression Data

Renal cell carcinoma (RCC) is one of the most common cancers worldwide with a nearly non-symptomatic course until the advanced stages of the disease. RCC can be distinguished into three subtypes: papillary (pRCC), chromophobe (chRCC) and clear cell renal cell carcinoma (ccRCC) representing up to 75% of all RCC cases. Detection and RCC monitoring tools are limited to standard imaging techniques, in combination with non-RCC specific morphological and biochemical read-outs. RCC subtype identification relays mainly on results of pathological examination of tumor slides. Molecular, clinically applicable and ideally non-invasive tools aiding RCC management are still non-existent, although molecular characterization of RCC is relatively advanced. Hence, many research efforts concentrate on the identification of molecular markers that will assist with RCC sub-classification and monitoring. Due to stability and tissue-specificity miRNAs are promising candidates for such biomarkers. Here, we performed a meta-analysis study, utilized seven NGS and seven microarray RCC studies in order to identify subtype-specific expression of miRNAs. We concentrated on potentially oncocytoma-specific miRNAs (miRNA-424-5p, miRNA-146b-5p, miRNA-183-5p, miRNA-218-5p), pRCC-specific (miRNA-127-3p, miRNA-139-5p) and ccRCC-specific miRNAs (miRNA-200c-3p, miRNA-362-5p, miRNA-363-3p and miRNA-204-5p, 21-5p, miRNA-224-5p, miRNA-155-5p, miRNA-210-3p) and validated their expression in an independent sample set. Additionally, we found ccRCC-specific miRNAs to be differentially expressed in ccRCC tumor according to Fuhrman grades and identified alterations in their isoform composition in tumor tissue. Our results revealed that changes in the expression of selected miRNA might be potentially utilized as a tool aiding ccRCC subclass discrimination and we propose a miRNA panel aiding RCC subtype distinction.

Role of the KEAP1-NRF2 Axis in Renal Cell Carcinoma

NRF2 is a transcription factor that coordinates the antioxidant response in many different tissues, ensuring cytoprotection from endogenous and exogenous stress stimuli. In the kidney, its function is essential in appropriate cellular response to oxidative stress, however its aberrant activation supports progression, metastasis, and resistance to therapies in renal cell carcinoma, similarly to what happens in other nonrenal cancers. While at the moment direct inhibitors of NRF2 are not available, understanding the molecular mechanisms that regulate its hyperactivation in specific tumor types is crucial as it may open new therapeutic perspectives. Here, we focus our attention on renal cell carcinoma, describing how NRF2 hyperactivation can contribute to tumor progression and chemoresistance. Furthermore, we highlight the mechanism whereby the many pathways that are generally altered in these tumors converge to dysregulation of the KEAP1-NRF2 axis.

miRNAs as Novel Biomarkers of Chronic Kidney Injury in Anabolic-Androgenic Steroid Users: An Experimental Study

miRNAs are a family of 20–22 non-coding nucleotides that control gene expression by inhibiting the translation of their target messenger RNAs (mRNAs). Two models have been proposed to elucidate the mechanism of action: they act either hindering mRNA translation or enhancing mRNA degradation. Anabolic-Androgenic Steroids (AASs) represent a class of drugs used to treat several diseases. In the last few years, AASs have frequently been used for aesthetic purposes, indeed, they form part of the larger group called image- and performance-enhancing drugs (IPEDs). Long-term AAS use can lead to serious health consequences. In this regard, the present study aimed to analyze the role of several microRNAs (miRNAs) in renal damage after AAS use, to better understand the underlying mechanisms. For this purpose, two miRNAs (miR-21 and miR-205) were tested in two groups: AAS group (seven males, mean age 33.28 ± 4.68 years; mean body mass index (BMI) 27.04 ± 1.07), and chronic kidney disease (CKD) group (seven males, mean age 66.2 ± 5.4 years; mean BMI 24.75 ± 1.35). Finally, the same miRNAs were tested in the “Control” group (seven males, mean age 44.85 ± 5.75 years; mean BMI 26.5 ± 1.88). Kolmogorov-Smirnov Test was used to determine the normality of data distribution. All variables were normally distributed. Student’s t-test was used for comparisons between two groups. Analyzing the results of the present study, the two tested miRNAs (miR-21 and miR-205) were significantly higher in the CKD group compared to the AAS group, with mir-21 being much more expressed than miR-205. This study represents a pilot study to define if these expression patterns could be studied in other biological samples (plasma, urine) in subjects with different kidney injury linked to chronic kidney diseases and AAS use, to identify reliable biomarkers that could be applied in clinical and forensic diagnostics, as well as a target for toxicological investigations or therapeutic treatments.

lncRNA small nucleolar RNA host gene 12 promotes renal cell carcinoma progression by modulating the miR‑200c‑5p/collagen type XI α1 chain pathway

Renal cell carcinoma (RCC) is a primary malignant kidney cancer subtype. It has been suggested that long non-coding RNAs (lncRNAs) serve important roles in the progression of kidney cancer. In fact, the lncRNA small nucleolar RNA host gene 12 (SNHG12) was discovered to be overexpressed in various types of cancer. However, to the best of our knowledge, the role of SNHG12 in RCC remains unclear. The present study aimed to investigate the function of SNHG12 and its underlying molecular mechanism of action in RCC. In patient samples and datasets from The Cancer Genome Atlas. Reverse transcription-quantitative PCR, demonstrated that SNHG12 expression levels were upregulated in RCC tumor tissues, but not in normal kidney tissues. SNHG12 upregulation was also observed in RCC cell lines. Kaplan-Meier survival analysis indicated a poor prognosis for those patients with RCC who had upregulated SNHG12 expression levels. Following lentivirus transduction, SNHG12 was successfully knocked down (validated by western blot analysis) and cell migration and invasion assays were performed. SNHG12 knockdown markedly inhibited cell viability and invasion, while increasing apoptosis in both A498 and 786O cell lines. The results of the luciferase reporter assay suggested that SNHG12 exerted its role by sponging microRNA (miR)-200c-5p, which led to the upregulation of its target gene, collagen type XI α1 chain (COL11A1). This was further validated, as miR-200c-5p inhibition reduced the effects of SNHG12 downregulation on cell viability and apoptosis, without affecting SNHG12 expression levels. Furthermore, the findings indicated that SNHG12 may partially exert its role through COL11A1, which was also upregulated in RCC. In conclusion, the results of the present study suggested that the SNHG12/miR-200c-5p/COL11A1 axis may be crucial for RCC progression, which provided an insight into potential therapeutic strategies for RCC treatment.

Comprehensive analysis of aberrantly expressed long non‑coding RNAs, microRNAs, and mRNAs associated with the competitive endogenous RNA network in cervical cancer

Cervical cancer is a common malignant disease that poses a serious health threat to women worldwide. Growing research efforts have focused on protein‑coding and non‑coding RNAs involved in the tumorigenesis and prognosis of various types of cancer. The potential molecular mechanisms and the interaction among long non‑coding RNAs (lncRNAs), microRNAs (miRNAs), and mRNAs require further investigation in cervical cancer. In the present study, lncRNA, miRNA, and mRNA expression profiles of 304 primary tumor tissues from patients with cervical cancer and 3 solid normal tissues from The Cancer Genome Atlas (TCGA) dataset were studied via RNA sequencing (RNA‑seq). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using R package clusterProfiler to annotate the principal functions of differentially expressed (DE) mRNAs. Kaplan‑Meier analysis was also conducted to investigate the effects of DElncRNAs, DEmiRNAs, and DEmRNAs on overall survival. A total of 2,255 mRNAs, 133 miRNAs, and 150 lncRNAs that were differentially expressed were identified with a threshold of P<0.05 and |fold change (FC)|>2. Functional enrichment analysis indicated that DEmRNAs were enriched in cancer‑associated KEGG pathways. Furthermore, 255 mRNAs, 15 miRNAs, and 12 lncRNAs that were significantly associated with overall survival in cervical carcinoma were also identified. Importantly, an miRNA‑mediated competitive endogenous RNA (ceRNA) network was successfully constructed based on the expression profiles of DElncRNAs and DEmRNAs. More importantly, it was found that the lncRNA EPB41L4A‑AS1 may function as a pivotal regulator in carcinoma of the uterine cervix. Taken together, the present study has provided novel insights into investigating the potential mechanisms underlying tumorigenesis, development, and prognosis of cervical cancer, and presented new potential avenues for cancer therapeutics.

MiR-362-5p, Which Is Regulated by Long Non-Coding RNA MBNL1-AS1, Promotes the Cell Proliferation and Tumor Growth of Bladder Cancer by Targeting QKI

In this study, we found miR-362-5p was upregulated in bladder cancer tissues and we predicted that QKI is potential a target of miR-362-5p and MBNL1-AS1 might be able to directly target to miR-362-5p. We attempted to evaluate whether miR-362-5p could play its roles in bladder cancer through regulating QKI (quaking) and whether the expression and function of miR-362-5p could be mediated by lncRNA MBNL1-AS1. We performed the gain- and loss-function experiments to explore the association between miR-362-5p expression and bladder cancer proliferation. In vivo, the nude mice were injected with miR-362-5p knockdown SW780 cells to assess the effects of miR-362-5p on tumor growth. The results showed upregulation of miR-362-5p promoted cell proliferation of bladder cancer cells. MBNL1-AS1 and QKI could directly bind with miR-362-5p, and knockdown of MBNL1-AS1 or QKI could abrogate the regulatory effects of miR-362-5p on bladder cancer cell proliferation. Furthermore, downregulation of miR-362-5p inhibited bladder tumor growth and increased QKI expression. Our data unveiled that miR-362-5p may play an oncogenic role in bladder cancer through QKI and MBNL1-AS1 might function as a sponge to mediate the miR-362-5p expression and function.

Cell proliferation is induced in renal cell carcinoma through miR-92a-3p upregulation by targeting FBXW7

Renal cell carcinoma (RCC) is the most common type of kidney cancer whose incidence has gradually increased worldwide. MicroRNAs (miRNAs) represent a type of short endogenous non-coding RNA containing approximately 22 nucleotides, which are capable of regulating mRNAs at the post-transcriptional level in human cells. miRNAs have been demonstrated to mediate gene expression by influencing important regulatory genes. Accumulating evidence indicates that certain miRNAs are involved in RCC development. The present study investigated the underlying mechanism and functional role of miR-92a-3p in RCC cells using reverse transcription-quantitative polymerase chain reaction, western blotting, 3′ UTR luciferase assay, cell proliferation assay and soft agar assay. The results demonstrated that miR-92a-3p expression level is significantly upregulated in RCC tissues and cell lines; however, F-box and WD repeat domain containing 7 (FBXW7) expression level was significantly downregulated in RCC tissues and cell lines. Subsequently, whether FBXW7 could be considered as a direct target of miR-92a-3p in RCC cells was investigated. The results demonstrated that miR-92a-3p overexpression significantly promoted RCC cell proliferation and colony formation. Conversely, miR-92a-3p downregulation significantly inhibited RCC cell proliferation and colony formation. In addition, FBXW7 knockdown significantly enhanced RCC cell proliferation and colony formation. Conversely, FBXW7 overexpression significantly inhibited RCC cell proliferation and colony formation. Collectively, these results demonstrated that miR-92a-3p/FBXW7 pathway may represent a novel strategy and therapeutic target for RCC.

Association of hypoxia-inducible factor-1α (HIF1α) 1790G/A gene polymorphism with renal cell carcinoma and prostate cancer susceptibility: a meta-analysis

BACKGROUND

This meta-analysis was performed to evaluate the relationship between hypoxia-inducible factor-1α (HIF1α) 1790G/A gene polymorphism and the susceptibility to renal cell carcinoma (RCC) and prostate cancer (PCa).

METHODS

Association investigations were identified and included from the Embase, Cochrane Library and PubMed databases on March 1, 2018, and eligible investigations were analyzed by meta-analysis. Odds ratios (OR) were used to express the dichotomous data, and the 95% confidence intervals (CI) were also calculated.

RESULTS

In this meta-analysis, we found that the AA genotype of HIF1α 1790G/A was positively associated with the risk of RCC in overall populations, Caucasians, but not for Asians. G allele and GG genotype were not associated with the susceptibility of RCC in overall populations, Caucasians, and Asians. The G allele was negatively associated with PCa susceptibility in overall populations, Asians, but not for Caucasians. GG genotype was negatively associated with PCa susceptibility in Asians, but not for overall populations and Caucasians. HIF1α 1790G/A AA genotype was not associated with PCa susceptibility in overall populations of Caucasians or Asians.

CONCLUSION

AA genotype of HIF1α 1790G/A was positively associated with RCC risk in overall populations and Caucasians. Furthermore, the G allele was negatively associated with prostate cancer susceptibility in overall populations, Asians, and GG genotype was negatively associated with PCa susceptibility in Asians.

MicroRNA-362-5p enhances the cisplatin sensitivity of gastric cancer cells by targeting suppressor of zeste 12 protein

Chemotherapy resistance is a major obstacle to the effective treatment of patients with gastric cancer (GC). Mounting evidence has indicated that the dysregulation of microRNAs (miRNAs) is associated with the sensitivity of cancer cells to chemotherapy. However, the mechanisms underlying miRNA-mediated chemoresistance in GC cells remain to be elucidated. The present study aimed to identify functional miRNAs that may regulate the sensitivity of human GC cells to cisplatin (DDP) treatment. miRNA microarray analysis was used to identify differentially expressed miRNAs between the human cisplatin-sensitive GC cell line SGC7901 and the corresponding cisplatin-resistant cell line SGC7901/DDP. miRNA (miR)-362-5p, which is associated with numerous types of tumors, was identified to be downregulated in the SGC7901/DDP cell line. However, the biological role of miR-362-5p in SGC7901/DDP cells remains to be explored. The expression level of miR-362-5p was demonstrated to be reduced in SGC7901/DDP cells compared with SGC7901 cells by reverse transcription-quantitative PCR. Upregulation of miR-362-5p significantly increased cisplatin sensitivity and cisplatin-induced apoptosis, whereas downregulation of miR-362-5p attenuated these effects. Databases predicted that suppressor of zeste 12 protein (SUZ12) may function as a target of miR-362-5p. In addition, the mRNA and protein expression levels of SUZ12 in SGC7901/DDP cells were significantly higher compared with SGC7901 cells and negatively associated with miR-362-5p expression. MTT and western blot analysis assays confirmed that knockdown of SUZ12 enhanced cisplatin sensitivity and decreased NF-κB/p65 protein levels in SGC7901/DDP cells. In addition, upregulation of miR-362-5p in SGC7901/DDP cells decreased the protein expression level of SUZ12, whereas downregulation of miR-362-5p increased the SUZ12 expression level. The results of the present study suggested that dysregulated miR-362-5p may target SUZ12 to promote the development of cisplatin resistance and attenuate cisplatin-induced apoptosis. Therefore, miR-362-5p upregulation combined with cisplatin treatment may serve as a promising therapeutic strategy for patients with cisplatin-resistant GC.