Epithelial-mesenchymal transition-related microRNA-200s regulate molecular targets and pathways in renal cell carcinoma

Epithelial-mesenchymal transition associated markers in sarcomatoid transformation of clear cell renal cell carcinoma

Epithelial-mesenchymal transition (EMT) plays a pivotal role in the development and progression of many cancers. Partial EMT (pEMT) could represent a critical step in tumor migration and dissemination. Sarcomatoid renal cell carcinoma (sRCC) is an aggressive form of renal cell carcinoma (RCC) composed of a carcinomatous (sRCC-Ca) and sarcomatous (sRCC-Sa) component. The role of (p)EMT in the progression of RCC to sRCC remains unclear. The aim of this study was to investigate the involvement of (p)EMT in RCC and sRCC. Tissue samples from 10 patients with clear cell RCC (ccRCC) and 10 patients with sRCC were selected. The expression of main EMT markers (miR-200 family, miR-205, SNAI1/2, TWIST1/2, ZEB1/2, CDH1/2, VIM) was analyzed by qPCR in ccRCC, sRCC-Ca, and sRCC-Sa and compared to non-neoplastic tissue and between both groups. Expression of E-cadherin, N-cadherin, vimentin and ZEB2 was analyzed using immunohistochemistry. miR-200c was downregulated in sRCC-Ca compared to ccRCC, while miR-200a was downregulated in sRCC-Sa compared to ccRCC. CDH1 was downregulated in sRCC-Sa when compared to any other group. ZEB2 was downregulated in ccRCC and sRCC compared to corresponding non-neoplastic kidney. A positive correlation was observed between CDH1 expression and miR-200a/b/c. Our results suggest that full EMT is not present in sRCC. Instead, discreet molecular differences exist between ccRCC, sRCC-Ca, and sRCC-Sa, possibly representing distinct intermediary states undergoing pEMT.

miR-4284 Functions as a Tumor Suppressor in Renal Cell Carcinoma Cells by Targeting Glutamate Decarboxylase 1

MicroRNAs (miRNAs) play a crucial role as oncogenic or tumor suppressors in the pathogenesis and progression of tumors. However, few studies have investigated the exact role of miR-4284 in renal cell carcinoma (RCC). We aimed to investigate the role of miR-4284 as a tumor suppressor in renal cancer cell lines. A498 and Caki-1 were transfected with miR-4284. The Cell Counting Kit-8, colony formation, apoptosis assays, and quantitative reverse transcription-polymerase chain reaction were used to evaluate tumor growth-inhibiting functions. The wound-healing, transwell, and sphere-formation assays were conducted to investigate tumorigenic characteristics. The potential target genes of miR-4284 were predicted and experimentally verified. A xenograft experiment was performed to estimate the tumor-growth-suppressive function of miR-4284. miR-4284 overexpression suppressed proliferation, induced apoptosis, and suppressed tumorigenic features of renal cancer cells. Glutamate decarboxylase 1 (GAD1) was directly targeted by miR-4284. A xenograft mouse model injected with Caki-1 cells transfected with miR-4284 showed significantly decreased tumor growth rate and volume. miR-4284 affected tumor growth, metastasis, and apoptosis of renal cancer cells in vitro and in vivo. These findings highlight the potential of miR-4284 as a target for anticancer miRNA therapeutics in RCC.

The role of miR-200 family in the regulation of hallmarks of cancer

MiRNAs are short non-coding RNAs that regulate gene expression post-transcriptionally contributing to the development of different diseases including cancer. The miR-200 family consists of five members, miR-200a, miR-200b, miR-200c, miR-141, and miR-429. Their expression is dysregulated in cancer tissue and their level is altered in the body fluids of cancer patients. Moreover, the levels of miR-200 family members correlate with clinical parameters such as cancer patients' survival which makes them potentially useful as diagnostic and prognostic biomarkers. MiRNAs can act as either oncomiRs or tumor suppressor miRNAs depending on the target genes and their role in the regulation of key oncogenic signaling pathways. In most types of cancer, the miR-200 family acts as tumor suppressor miRNA and regulates all features of cancer. In this review, we summarized the expression pattern of the miR-200 family in different types of cancer and their potential utility as biomarkers. Moreover, we comprehensively described the role of miR-200 family members in the regulation of all hallmarks of cancer proposed by Hanahan and Weinberg with the focus on the epithelial-mesenchymal transition, invasiveness, and metastasis of tumor cells.

microRNA-99a-5p induces cellular senescence in gemcitabine-resistant bladder cancer by targeting SMARCD1

Patients with advanced bladder cancer are generally treated with a combination of chemotherapeutics, including gemcitabine, but the effect is limited due to acquisition of drug resistance. Thus, in this study, we investigated the mechanism of gemcitabine resistance. First, gemcitabine‐resistant cells were established and resistance confirmed in vitro and in vivo. Small RNA sequencing analyses were performed to search for miRNAs involved in gemcitabine resistance. miR‐99a‐5p, selected as a candidate miRNA, was downregulated compared to its parental cells. In gain‐of‐function studies, miR‐99a‐5p inhibited cell viabilities and restored sensitivity to gemcitabine. RNA sequencing analysis was performed to find the target gene of miR‐99a‐5p. SMARCD1 was selected as a candidate gene. Dual‐luciferase reporter assays showed that miR‐99a‐5p directly regulated SMARCD1. Loss‐of‐function studies conducted with si‐RNAs revealed suppression of cell functions and restoration of gemcitabine sensitivity. miR‐99a‐5p overexpression and SMARCD1 knockdown also suppressed gemcitabine‐resistant cells in vivo. Furthermore, β‐galactosidase staining showed that miR‐99a‐5p induction and SMARCD1 suppression contributed to cellular senescence. In summary, tumor‐suppressive miR‐99a‐5p induced cellular senescence in gemcitabine‐resistant bladder cancer cells by targeting SMARCD1.

Molecular Mechanisms of Resistance to Immunotherapy and Antiangiogenic Treatments in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common histological subtype arising from renal cell carcinomas. This tumor is characterized by a predominant angiogenic and immunogenic microenvironment that interplay with stromal, immune cells, and tumoral cells. Despite the obscure prognosis traditionally related to this entity, strategies including angiogenesis inhibition with tyrosine kinase inhibitors (TKIs), as well as the enhancement of the immune system with the inhibition of immune checkpoint proteins, such as PD-1/PDL-1 and CTLA-4, have revolutionized the treatment landscape. This approach has achieved a substantial improvement in life expectancy and quality of life from patients with advanced ccRCC. Unfortunately, not all patients benefit from this success as most patients will finally progress to these therapies and, even worse, approximately 5 to 30% of patients will primarily progress. In the last few years, preclinical and clinical research have been conducted to decode the biological basis underlying the resistance mechanisms regarding angiogenic and immune-based therapy. In this review, we summarize the insights of these molecular alterations to understand the resistance pathways related to the treatment with TKI and immune checkpoint inhibitors (ICIs). Moreover, we include additional information on novel approaches that are currently under research to overcome these resistance alterations in preclinical studies and early phase clinical trials.

Determinants of resistance to VEGF-TKI and immune checkpoint inhibitors in metastatic renal cell carcinoma

Vascular endothelial growth factor tyrosine kinase inhibitors (VEGF-TKIs) have been the mainstay of treatment for patients with advanced renal cell carcinoma (RCC). Despite its early promising results in decreasing or delaying the progression of RCC in patients, VEGF-TKIs have provided modest benefits in terms of disease-free progression, as 70% of the patients who initially respond to the treatment later develop drug resistance, with 30% of the patients innately resistant to VEGF-TKIs. In the past decade, several molecular and genetic mechanisms of VEGF-TKI resistance have been reported. One of the mechanisms of VEGF-TKIs is inhibition of the classical angiogenesis pathway. However, recent studies have shown the restoration of an alternative angiogenesis pathway in modulating resistance. Further, in the last 5 years, immune checkpoint inhibitors (ICIs) have revolutionized RCC treatment. Although some patients exhibit potent responses, a non-negligible number of patients are innately resistant or develop resistance within a few months to ICI therapy. Hence, an understanding of the mechanisms of VEGF-TKI and ICI resistance will help in formulating useful knowledge about developing effective treatment strategies for patients with advanced RCC. In this article, we review recent findings on the emerging understanding of RCC pathology, VEGF-TKI and ICI resistance mechanisms, and potential avenues to overcome these resistance mechanisms through rationally designed combination therapies.

EHHADH contributes to cisplatin resistance through regulation by tumor-suppressive microRNAs in bladder cancer

Background

Cisplatin-based chemotherapy is recommended as the primary treatment for advanced bladder cancer (BC) with unresectable or metastatic disease. However, the benefits are limited due to the acquisition of drug resistance. The mechanisms of resistance remain unclear. Although there are some reports that some molecules are associated with cisplatin resistance in advanced BC, those reports have not been fully investigated. Therefore, we undertook a new search for cisplatin resistance-related genes targeted by tumor suppressive microRNAs as well as genes that were downregulated in cisplatin-resistant BC cells and clinical BC tissues.

Methods

First, we established cisplatin-resistant BOY and T24 BC cell lines (CDDP-R-BOY, CDDP-R-T24). Then, Next Generation Sequence analysis was performed with parental and cisplatin-resistant cell lines to search for the microRNAs responsible for cisplatin resistance. We conducted gain-of-function analysis of microRNAs and their effects on cisplatin resistance, and we searched target genes comprehensively using Next Generation mRNA sequences.

Results

A total of 28 microRNAs were significantly downregulated in both CDDP-R-BOY and CDDP-R-T24. Among them, miR-486-5p, a tumor suppressor miRNA, was negatively correlated with the TNM classification of clinical BC samples in The Cancer Genome Atlas (TCGA) database. Transfection of miRNA-486-5p significantly inhibited cancer cell proliferation, migration, and invasion, and also improved the cells’ resistance to cisplatin. Among the genes targeted by miRNA-486-5p, we focused on enoyl-CoA, hydratase/3-hydroxyacyl CoA dehydrogenase (EHHADH), which is involved in the degradation of fatty acids. EHHADH was directly regulated by miRNA-486-5p as determined by a dual-luciferase reporter assay. Loss-of-function study using EHHADH si-RNA showed significant inhibitions of cell proliferation, migration, invasion and the recovery of cisplatin sensitivity.

Conclusion

Identification of EHHADH as a target of miRNA-486-5p provides novel insights into the potential mechanisms of cisplatin resistance in BC.

m5C RNA Methylation Primarily Affects the ErbB and PI3K-Akt Signaling Pathways in Gastrointestinal Cancer

5-Methylcytosine (m⁵C) is a kind of methylation modification that occurs in both DNA and RNA and is present in the highly abundant tRNA and rRNA. It has an important impact on various human diseases including cancer. The function of m⁵C is modulated by regulatory proteins, including methyltransferases (writers) and special binding proteins (readers). This study aims at comprehensive study of the m⁵C RNA methylation-related genes and the main pathways under m⁵C RNA methylation in gastrointestinal (GI) cancer. Our result showed that the expression of m⁵C writers and reader was mostly up-regulated in GI cancer. The NSUN2 gene has the highest proportion of mutations found in GI cancer. Importantly, in liver cancer, higher expression of almost all m⁵C regulators was significantly associated with lower patient survival rate. In addition, the expression level of m⁵C-related genes is significantly different at various pathological stages. Finally, we have found through bioinformatics analysis that m⁵C regulatory proteins are closely related to the ErbB/PI3K–Akt signaling pathway and GSK3B was an important target for m⁵C regulators. Besides, the compound termed streptozotocin may be a key candidate drug targeting on GSK3B for molecular targeted therapy in GI cancer.

TNFAIP8 promotes the migration of clear cell renal cell carcinoma by regulating the EMT

Background: Clear cell renal cell carcinoma (ccRCC) is characterized by high metastatic potential, and the epithelial-mesenchymal transition (EMT) has been shown to play a key role in multiple cancer progression, migration and metastasis and is the leading cause of poor prognosis. Currently, tumor necrosis factor-α-induced protein 8 (TNFAIP8/TIPE) is a newly discovered tumorigenesis factor, and TNFAIP8 and the EMT influence the migration of renal cancer cells.

Methods: In this study, we first analyzed the relationship between TNFAIP8 and ccRCC using bioinformatics, followed by immunohistochemistry to evaluate the relationship between the two in clinical samples. Subsequently, reverse transcription PCR and western blotting confirmed the expression of TNFAIP8 in ccRCC cells. Furthermore, we measured the migration and invasion abilities by using wound healing and transwell assays after overexpression or knockdown of TNFAIP8 in cells. In addition, we verified whether TNFAIP8 affects the EMT process in ccRCC by quantitative real-time PCR, western blotting, immunohistochemistry and immunofluorescence experiments.

Results: Through database analysis, we found that TNFAIP8 was highly expressed in ccRCC patients and was positively correlated with tumor stage and grade, indicating that TNFAIP8 is associated with the development of advanced ccRCC and poor prognosis. We subsequently confirmed that TNFAIP8 was abnormally overexpressed in clinical samples and ccRCC cell lines and that TNFAIP8 promoted ccRCC cell migration and invasion in vitro. Finally, we found that TNFAIP8 regulated EMT-related molecule expression and regulated the EMT process.

Conclusion: High expression of TNFAIP8 reinforces migration and regulates the EMT in ccRCC, conferring the metastatic potential of ccRCC and suggesting that TNFAIP8 may be a potential therapeutic target for the treatment of advanced ccRCC.

The circular RNA hsa-circ-0072309 plays anti-tumour roles by sponging miR-100 through the deactivation of PI3K/AKT and mTOR pathways in the renal carcinoma cell lines

Aims: To explore the roles and regulatory mechanisms of the circular RNA (circRNA)-hsa-circ-0072309 in CAKI-1 and ACHN cells. Methods: CAKI-1 and ACHN cells were transfected with hsa-circ-0072309 overproduction vector (circRNA) and microRNA-100 (miR-100) mimic or the corresponding controls. Cell viability was detected with the CCK-8. The protein expression levels of p53, c-Myc, cleaved-caspase-3/9, matrix metalloproteinase (MMP)-2/9, vimentin, AKT, PI3K and mTOR were individually determined through western blot. qRT-PCR was used to examine the expressions of hsa-circ-0072309 and miR-100. The apoptotic rate and the migration or invasion rates were separately determined by the annexin v-FITC/PI with a flow cytometer and modified two-chamber migration assay or millicell hanging cell culture. Results: The hsa-circ-0072309 was poorly expressed in tumor tissue. Abundant hsa-circ-0072309 induced the inhibitions of cell proliferation, migration and invasion, as well as the PI3K/AKT and the mTOR cascades but enhancement of apoptosis. circRNA stimulated the down-regulation of miR-100, which was low-expressed in tumour tissue and whose overproduction abolished the impacts of circRNA on these elements mentioned above. Conclusion: The hsa-circ-0072309 played anti-tumour roles by targeting miR-100 by blocking the PI3K/AKT and mTOR cascades in the CAKI-1 and ACHN cell lines.

The miR-200 family as prognostic markers in clear cell renal cell carcinoma

OBJECTIVES

microRNAs (miRNAs) are small noncoding RNAs that regulate gene expression by mRNA cleavage or translational repression. The miR-200 family is involved in the regulation of various tumor biologic processes including apoptosis, proliferation, invasion, and metastasis. They function mainly as tumor suppressors. In this study, we aim to validate the prognostic significance of miR-200 family using large cohort of primary clear cell renal cell carcinoma (ccRCC) and matched normal tissue and to explore the role of miR-200 family in RCC pathogenesis and progression.

MATERIALS AND METHODS

We analyzed the expression of 3 members of the miR-200 family; miR-141, miR-200b, and miR-200c, between primary ccRCC, matched normal renal tissues, and nonmatched metastatic RCC. We compared clinicopathologic parameter including disease-free survival to miR-200 family expression. Additionally, we validated our results using The Cancer Genome Atlas dataset. We explored functional role of these miRNAs by bioinformatics analyses.

RESULTS AND CONCLUSIONS

Expression of miR-200 family significantly decreased in cancer compared to non-neoplastic tissues. miR-141 and miR-200b were significantly down-regulated in metastatic than primary tumors. There was statistically significant negative association between all 3 miRNAs and tumor size and stage. As binary variables, univariate analyses revealed that miR-141, miR-200b, and miR-200c-positive ccRCC patients have a statistically significant lower chance of disease-recurrence or relapse and multivariate analyses showed miR-200b and miR-200c-positive patients have longer disease-free survival. We could predict disease-free survival better when 2 or more miRNAs were used as a combination. Overall survival analysis using The Cancer Genome Atlas data revealed that miR-200b-positive patients have significantly better survival. These results suggest that miR-141, miR-200b, and miR-200c are independent prognostic markers for ccRCC. Targets of these miRNAs are associated with pathways related to cancer invasion and metastasis, including TRAIL pathway, VEGF and VEGFR signaling network, and epithelial-mesenchymal transition.

Current Concepts of Non-Coding RNAs in the Pathogenesis of Non-Clear Cell Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a relatively rare malignancy of the urinary tract system. RCC is a heterogenous disease in terms of underlying histology and its associated underlying pathobiology, prognosis and treatment schedule. The most prevalent histological RCC subtype is clear-cell renal cell carcinoma (ccRCC), accounting for about 70-80% of all RCCs. Though the pathobiology and treatment schedule for ccRCC are well-established, non-ccRCC subtypes account for 20%-30% of RCC altogether, and their underlying molecular biology and treatment options are poorly defined. The class of non-coding RNAs-molecules that are generally not translated into proteins-are new cancer drivers and suppressors in all types of cancer. Of these, small non-coding microRNAs (miRNAs) contribute to carcinogenesis by regulating posttranscriptional gene silencing. Additionally, a growing body of evidence supports the role of long non-coding RNAs (lncRNAs) in cancer development and progression. Most studies on non-coding RNAs in RCC focus on clear-cell histology, and there is a relatively limited number of studies on non-ccRCC subtypes. The aim of this review is to give an overview of the current knowledge regarding the role of non-coding RNAs (including short and long non-coding RNAs) in non-ccRCC and to highlight possible implications as diagnostic, prognostic and predictive biomarkers.

Up-regulation of microRNA-200c-3p inhibits invasion and migration of renal cell carcinoma cells via the SOX2-dependent Wnt/β-catenin signaling pathway

Background

MicroRNA-200c-3p (miR-200c-3p) has been revealed to be related to renal cell carcinoma (RCC) progression, while the inner mechanisms remain unknown. In our study, we intend to unearth the capability of miR-200c-3p in RCC development via the Wnt/β-catenin signaling pathway through binding to SOX2.

Methods

miR-200c-3p, SOX2, β-catenin and GSK3β expression in both tissues and cells of RCC were detected by RT-qPCR or western blot analysis. miR-200c-3p was restored or silenced to determine their biological functions of RCC cells. Expression of SOX2 and related proteins in the Wnt/β-catenin signaling pathway were evaluated by RT-qPCR and western blot analysis. The effect of the combination of downregulated miR-200c-3p and downregulated SOX2 on cell biological behavior change was also determined.

Results

Initially, we found that miR-200c-3p was declined while SOX2, β-catenin and GSK3β was elevated in RCC tissues and cells. A498 cells with the largest difference in miR-200c-3p expression and OS-RC-2 cells with the smallest difference were selected for subsequent experiments. Additionally, upregulated miR-200c-3p and downregulated SOX2 was determined to suppress proliferation, migration, invasion and induce apoptosis of RCC cells. Furthermore, miR-200c-3p inhibited SOX2 to inactivate the Wnt/β-catenin signaling pathway.

Conclusion

Collectively, this study highlights that upregulated miR-200c-3p inhibits expression of SOX2, thereby inhibiting development of RCC cells via modulating the Wnt/β-catenin signaling pathway activation.

MicroRNA-200b is downregulated and suppresses metastasis by targeting LAMA4 in renal cell carcinoma

Background

Metastasis is the primary cause of tumor death in renal cell carcinoma (RCC). Improved diagnostic markers of metastasis are critically needed for RCC. MicoRNAs are demonstrated to be stable and significant biomarkers for several malignancies. In this study, we aimed to explore the metastasis related microRNAs and its mechanism in RCC.

Methods

The relationship between microRNAs expression and prognosis and metastasis of RCC patients were explored by data mining through expression profiles from The Cancer Genome Atlas (TCGA). A total of 80 RCC tissues and adjacent normal kidney tissues were obtained from Department of Urology, Peking University First Hospital. Expression of microRNA-200b (miR-200b) in RCC tissues and cell lines were determined by bioinformatic data mining and quantitative real-time PCR (qRT-PCR). The effects of miR-200b on cell proliferation, migration and invasion were determined by cell counting kit-8 and colony formation assay, wound healing assay and Boyden chamber assay. Mouse cell-derived xenograft and patient-derived xenograft model were also performed to evaluate the effects of miR-200b on tumor growth and metastasis in vivo. The molecular mechanism of miR-200b function was investigated using bioinformatic target predication and high-throughput cDNA sequencing (RNA-seq) and validated by luciferase reporter assay, qRT-PCR, Western blot and immunostaining in vitro and in vivo.

Findings

Our findings indicates that miR-200b is frequently downregulated and have potential utility as a biomarker of metastasis and prognosis in RCC. Interestingly, ectopic expression of miR-200b in the Caki-1 and OSRC-2 cell lines suppresses cell migration and invasion in vitro as well as tumor metastases in vivo. However, miR-200b has no effect on cell proliferation in vitro and tumor growth in vivo. In addition, bioinformatics target predication and RNA-seq results reveals that Laminin subunit alpha 4 (LAMA4) is one target of miR-200b and significantly inhibited by miR-200b in vitro and in vivo.

Interpretation

These results demonstrate a previously undescribed role of miR-200b as a suppressor of tumor metastasis in RCC by directly destabilizing LAMA4 mRNA.

Tumor‑suppressive microRNA‑223 targets WDR62 directly in bladder cancer

miRNA‑223 (miR‑223) has been reported to function not only as a tumor suppressor, but also as an oncogenic microRNA (miRNA or miR) in various cancer cells. Therefore, the functional role of miR‑223 has not been elucidated to date, at least to the best of our knowledge. We previously performed the deep sequencing analysis of clinical bladder cancer (BC) specimens. It was revealed that miR‑223 expression was significantly downregulated in BC, suggesting that miR‑223 functions as a tumor suppressor miRNA in BC. The aim of this study was to investigate the functional roles of miR‑223 and to identify its targets in BC. The expression levels of miR‑223 were significantly decreased in our clinical BC specimens. The Cancer Genome Atlas (TCGA) database indicated that miR‑223 expression was related to lymphovascular invasion and distant metastasis. The restoration of miR‑223 expression significantly inhibited tumor aggressiveness and induced apoptosis via caspase‑3/7 activation in BC cells. WD repeat domain 62 (WDR62), a candidate target of miR‑223 according to in silico analyses, has been previously proposed to play a role in neurodevelopment. Direct binding between WDR62 and miR‑223 was confirmed by luciferase assay. The TCGA database revealed positive associations between WDR62 mRNA expression and a higher tumor grade and stage in BC. The knockdown of WDR62 significantly inhibited tumor aggressiveness and induced the apoptosis of BC cells. On the whole, the findings of this study reveal a novel miR‑223 target, oncogenic WDR62, and provided insight into the oncogenesis of BC.

TGF-β inducible epithelial-to-mesenchymal transition in renal cell carcinoma

Epithelial-to-mesenchymal transition (EMT) is a crucial step in cancer progression and the number one reason for poor prognosis and worse overall survival of patients. Although this essential process has been widely studied in many solid tumors as e.g. melanoma and breast cancer, more detailed research in renal cell carcinoma (RCC) is required, especially for the major EMT-inducer transforming growth factor beta (TGF-β). Here, we provide a study of six different RCC cell lines of two different RCC subtypes and their response to recombinant TGF-β1 treatment. We established a model system shifting the cells to a mesenchymal cell type without losing their mesenchymal character even in the absence of the external stimulus. This model system forms a solid basis for future studies of the EMT process in RCCs to better understand the molecular basis of this process responsible for cancer progression.

Key miRNAs and target genes played roles in the development of clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (CCRCC) is the most aggressive form of renal cell carcinoma (RCC).

OBJECTIVE

This study was aimed to identify the differentially expressed miRNAs and target genes in CCRCC.

METHODS

The miRNA and mRNA next-generation sequencing data were downloaded from The Cancer Genome Atlas (TCGA) dataset. Differential expression analysis was performed, followed by correlation analysis of miRNA-mRNA. Functional enrichment and survival analysis was also performed.

RESULTS

Seven hundred and eighty-seven patients with CCRCC from TCGA data portal were included in this study. A total of 52 differentially expressed miRNAs were identified in CCRCC. Then 2361 differentially expressed genes (DEGs) were identified. Prediction analysis and correlation analysis revealed that 89 miRNA-mRNA pairs were not only predicted by algorithms but also had a significant inverse relationship. Several differentially expressed miRNAs such as hsa-mir-501 and their target genes including AK1, SLC25A15 and PCDHGC3 had a significant prognostic value for CCRCC patients.

CONCLUSIONS

Alterations of differentially expressed miRNAs and target genes may be involved in the development of CCRCC and can be considered as the prognostic markers for CCRCC.

The role of focal adhesion kinase in transforming growth factor-β2 induced migration of human lens epithelial cells

The migration of lens epithelial cells towards the posterior capsule is a key event in the development of posterior capsule opacification (PCO). Accumulating evidence has described crosstalk between growth factors and adhesive signaling pathways in wound healing and cell migration. The aim of the present study was to elucidate an aberrant transforming growth factor (TGF)‑β2 signaling pathway that regulated the migration of lens epithelial cells in the pathological context of PCO. The expression of fibronectin, focal adhesion kinase (FAK) and phosphorylated (p)‑FAK in HLE‑B3 cells following TGF‑β2 treatment was determined by western blot analysis and the expression of integrin α5β1 was detected by flow cytometry. Cell migration capacity was measured by wound healing and Transwell assays in the presence of 1,2,4,5‑tetraaminobenzene tetrahydrochloride, a selective FAK inhibitor, fibronectin small interfering RNA interference, arginylglycylaspartic acid peptides or α5β1‑integrin neutralizing antibodies. The 1,2,4,5‑tetraaminobenzene tetrahydrochloride was administered daily to 16 rabbits following cataract surgery. Fibronectin and TGF‑β expression were increased in the PCO group, demonstrated by immunofluorescence assays. PCO grading was conducted by slit‑lamp biomicroscopy and evaluation of posterior capsule opacification software. It was observed that TGF‑β2 promoted HLE‑B3 cell migration and upregulated fibronectin expression, which was followed by an increased phosphorylation of FAK. In addition, TGF‑β2 treatment and fibronectin surface coating significantly increased cell migration and FAK activation, which was inhibited by disrupting fibronectin‑integrin α5β1 interaction with the arginylglycylaspartic acid peptide, α5β1‑integrin neutralizing antibody or fibronectin depletion. Finally, suppression of FAK signaling by its inhibitor significantly decreased cell migration in vitro and attenuated PCO development in vivo. In summary, TGF‑β2 was indicated to promote the migration of lens epithelial cells through the TGF‑β2/fibronectin/integrin/FAK axis. Inhibition of FAK activity decreased TGF‑β2‑mediated cell migration in vitro and improved the symptoms of PCO in a rabbit model.

MiR-429 regulates rat liver regeneration and hepatocyte proliferation by targeting JUN/MYC/BCL2/CCND1 signaling pathway

Increasing evidence indicates that miR-429 is involved in tumor suppression in various human cancers. However, its role in liver regeneration remains unexplored. Liver regeneration is a highly orchestrated process that can be regulated by microRNAs (miRNAs), although the mechanisms are largely unclear. In this study, we aimed to identify the role of miR-429 in hepatocyte proliferation during liver regeneration. First, we performed microarray analysis and qRT-PCR. Results indicated that miR-429 level in rat liver markedly decreased 30 h after partial hepatectomy, and miR-429 overexpression disrupted BRL-3A proliferation and the transition of G1 to S phase in rat hepatocyte and promoted hepatocyte apoptosis. By contrast, miR-429 down-regulation had inverse effects. MiR-429 negatively regulated JUN expression in vitro and in vivo. After using JUN siRNA, we found that JUN inhibition mediates the effect of miR-429 in hepatocyte proliferation and growth and miR-429 negatively regulates JUN/MYC/BCL2/CCND1 signaling pathways. Our results also indicated that miR-429 inhibits hepatocyte proliferation and liver regeneration by targeting JUN/MYC/BCL2/CCND1.

MiR-429 Regulated by Endothelial Monocyte Activating Polypeptide-II (EMAP-II) Influences Blood-Tumor Barrier Permeability by Inhibiting the Expressions of ZO-1, Occludin and Claudin-5

The blood-tumor barrier (BTB) hinders delivery of chemotherapeutic drugs to tumors in the brain; previous studies have shown that the BTB can be selectively opened by endothelial monocyte activating polypeptide-II (EMAP-II), but the specific mechanism involved remains elusive. In this study, we found that microRNA-429 (miR-429) expression in glioma vascular endothelial cells (GECs) was far lower than in human brain microvascular endothelial cells (ECs). miR-429 had lower expression in GECs and glioma tissues compared to ECs or normal tissues of the brain. Furthermore, miR-429 had lower expression in high grade glioma (HGG) than in low grade glioma (LGG). In in vitro BTB models, we also found that EMAP-II significantly increased BTB permeability, decreased expression of ZO-1, occludin and claudin-5 in GECs, in a time- and dose-dependent manner. EMAP-II greatly increased miR-429 expression in GECs of the BTB models in vitro. Overexpression of miR-429 in GECs significantly decreased the transepithelial electric resistance (TEER) values in BTB models, and led to enhanced horseradish peroxidase (HRP) flux. Overexpression of miR-429 in GECs significantly decreased the expression of tight junction (TJ)-associated proteins (ZO-1, occludin and claudin-5), and decreased the distribution continuity. Silencing of miR-429 in GECs increased the expression of TJ-associated proteins and the distribution continuity. The dual-luciferase reporter assay revealed that ZO-1 and occludin were target genes of miR-429, and we demonstrated that miR-429 overexpression markedly down-regulated protein expression of p70S6K, as well as its phosphorylation levels. The dual-luciferase reporter assay also showed that p70S6K was a target gene of miR-429; miR-429 overexpression down-regulated expression and phosphorylation levels of p70S6K, and also decreased phosphorylation levels of S6 and increased BTB permeability. Conversely, silencing of miR-429 increased the expression and phosphorylation levels of p70S6K, and increased phosphorylation levels of S6, while decreasing BTB permeability. In conclusion, the results indicated that EMAP-II caused an increase in miR-429 expression that directly targeted TJ-associated proteins, which were negatively regulated; on the other hand, miR-429 down-regulated the expression of TJ-associated proteins by targeting p70S6K, also negatively regulated. As a result, the BTB permeability increased.

MiR-200c-3p inhibits cell migration and invasion of clear cell renal cell carcinoma via regulating SLC6A1

In this study, we investigated the mechanism of miR-200c-3p and SLC6A1 in regulating cell activity of clear cell renal cell carcinoma (CCRCC). The mRNA and miRNA expressions of tissue specimens were analyzed by CapitalBio Corporation (Beijing, China). The expression of SLC6A1 in CCRCC cells was examined through qRT-PCR and western blot. The migration and invasion ability of 786-O cells was testified by transwell assay after transfected. 786-O cell proliferation ability was detected by MTT assay. Dual luciferase reporter assay verified the association between SLC6A1 and miR-200c-3p. SLC6A1 was high expressed and miR-200c-3p was low expressed in CCRCC tissues and cells. Besides, lower SLC6A1 expression indicated longer survival time and higher survival rate. MiR-200c-3p could directly target at SLC6A1 and reduce its expression. MiR-200c-3p inhibited the proliferation, migration and invasion in 786-O cells by down-regulating SLC6A1 expression. The results suggested that the miR-200c-3p served as a suppressor for CCRCC via down-regulating SLC6A1.

A miRNA-based classification of renal cell carcinoma subtypes by PCR and in situ hybridization

Renal cell carcinoma (RCC) constitutes an array of morphologically and genetically distinct tumors the most prevalent of which are clear cell, papillary, and chromophobe RCC. Accurate distinction between the typically benign-behaving renal oncocytoma and RCC subtypes is a frequent challenge for pathologists. This is critical for clinical decision making. Subtypes also have different survival outcomes and responses to therapy. We extracted RNA from ninety formalin-fixed paraffin-embedded (FFPE) tissues (27 clear cell, 29 papillary, 19 chromophobe, 4 unclassified RCC and 11 oncocytomas). We quantified the expression of six miRNAs (miR-221, miR-222, miR-126, miR-182, miR-200b and miR-200c) by qRT-PCR, and by in situ hybridization in an independent set of tumors. We developed a two-step classifier. In the first step, it uses expression of either miR-221 or miR-222 to distinguish the clear cell and papillary subtypes from chromophobe RCC and oncocytoma (miR-221 AUC: 0.96, 95% CI: 0.9132-1.014, p < 0.0001 and miR-222 AUC: 0.91, 95% CI: 0.8478-0.9772, p < 0.0001). In the second step, it uses miR-126 to discriminate clear cell from papillary RCC (AUC: 1, p < 0.0001) and miR-200b to discriminate chromophobe RCC from oncocytoma (AUC: 0.95, 95% CI: 0.8933-1.021, p < 0.0001). In situ hybridization showed a nuclear staining pattern. miR-126, miR-222 and miR-200b were significantly differentially expressed between the subtypes by in situ hybridization. miRNA expression could distinguish RCC subtypes and oncocytoma. miRNA expression assessed by either PCR or in situ hybridization can be a clinically useful diagnostic tool to complement morphologic renal tumor classification, improving diagnosis and patient management.

MicroRNA‑141 inhibits epithelial‑mesenchymal transition, and ovarian cancer cell migration and invasion

The effects of microRNA-141 (miR-141) on epithelial-mesenchymal transition (EMT), and ovarian cancer cell migration and invasion were investigated. SKOV3 cells were transfected with the miR-141 mimic (mimic group), inhibitor (inhibitor group) and nonspecific sequences (NC group), and left untransfected group (blank group). The reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-141 in SKOV3 cell lines. Then, mRNA levels and protein expression of EMT markers were determined by RT-qPCR and western blotting, respectively. Cell proliferation was assessed using an MTT assay, followed by analysis of cell invasion and migration. SPSS software was used for statistical analysis. The results demonstrated that miR-141 expression in the mimic group was increased compared with the NC or blank group. Compared with the NC or blank group, upregulation of epithelial-cadherin (E-cadherin) and integrin-β, and downregulation of zinc finger E-box-binding homeobox (ZEB) was observed in the mimic group. The rate of cell proliferation decreased in the mimic group and increased in the inhibitor group when compared with the NC group (P<0.05). The number of invasive cells significantly increased in the inhibitor group and decreased in the mimic group when compared with the NC group (P<0.01). Compared with the NC group, the migratory rate was decreased in the mimic group, and increased in the inhibitor group at 24 and 48 h (all P<0.01). In conclusion, overexpression of miR-141 caused upregulation of E-cadherin, inhibited cell proliferation and EMT, and decreased cell invasion and migration in the SKOV3 cell line.

The putative tumor suppressor microRNA-30a-5p modulates clear cell renal cell carcinoma aggressiveness through repression of ZEB2

Clear cell renal cell carcinoma (ccRCC), the most common subtype of renal cell carcinoma, can easily invade local tissues and metastasize, and is resistant to currently available treatments. Recent studies profiling microRNA expression in ccRCC have suggested miR-30a-5p may be deregulated in these cancer cells. To determine its role and mechanism of action in ccRCC, miR-30-5p expression levels were quantified and functions were analyzed using in vitro and in vivo experiments and bioinformatics. A decrease in miR-30a-5p expression was frequently noted in ccRCC cells and tissues. Importantly, low miR-30a-5p levels were significantly associated with a poor ccRCC patient prognosis. Stable overexpression of miR-30a-5p in 769-P cells was sufficient to prevent cellular proliferation and invasion in vitro and in vivo. Upon further examination, it was found that miR-30a-5p directly targeted the 3'-UTR of ZEB2 and suppressed ccRCC cell epithelial-mesenchymal transition. In addition, miR-30a-5p may be downregulated by the long non-coding RNA DLEU2. Taken together, these data reveal an important role for miR-30a-5p in the regulation of ccRCC proliferation and invasion, and indicate the potential for miR-30a-5p in applications furthering ccRCC prognostics and therapeutics.

Knockdown of Collagen Triple Helix Repeat Containing-1 Inhibits the Proliferation and Epithelial-to-Mesenchymal Transition in Renal Cell Carcinoma Cells

Collagen triple helix repeat containing-1 (CTHRC1), a secreted glycoprotein, is frequently upregulated in human cancers. However, the functional role of CTHRC1 in renal cell carcinoma (RCC) remains unclear. Thus, the aim of this study was to explore the role of CTHRC1 in RCC. Our results demonstrated that CTHRC1 was upregulated in RCC tissues and cell lines. Knockdown of CTHRC1 significantly inhibits the proliferation in RCCs. Furthermore, knockdown of CTHRC1 significantly inhibited the epithelial-to-mesenchymal transition (EMT) process in RCCs, as well as suppressed RCC cell migration and invasion. Mechanistically, knockdown of CTHRC1 inhibited the expression of β-catenin, c-Myc, and cyclin D1 in RCC cells. In conclusion, the results of the present study indicated that CTHRC1 downregulation inhibited proliferation, migration, EMT, and β-catenin expression in RCC cells. Therefore, CTHRC1 may be a potential therapeutic target for the treatment of RCC.

miRNA-200c and miRNA-141 as potential prognostic biomarkers and regulators of epithelial-mesenchymal transition in eyelid sebaceous gland carcinoma

BACKGROUND

MicroRNA (miRNA)-200c and miRNA-141 are tumour suppressors, which regulate epithelial-mesenchymal transition (EMT), leading to tumour invasion and metastasis in various malignancies. miRNA-200c and miRNA-141 maintain the epithelial phenotype by post-transcriptionally inhibiting the E-cadherin repressors, zinc finger E-box binding homeobox (ZEB)1 and ZEB2. The present study was performed to determine the prognostic significance of miRNA-200c and miRNA-141, and their association with EMT markers ZEB1, ZEB2 and E-cadherin in eyelid sebaceous gland carcinoma (SGC).

METHODS

Expression levels of miRNA-200c and miRNA-141 were determined in 42 eyelid SGC cases by quantitative real-time PCR (qPCR). Their association with ZEB1, ZEB2 and E-cadherin was determined by qPCR and immunohistochemistry. Kaplan-Meier plots and Spearman's rank correlation tests were applied to analyse the data. Patients were followed up for 7-44 months.

RESULTS

Low expression levels of miRNA-200c and miRNA-141 were seen in 36/42 (86%) and 28/42 (67%) cases, respectively. Low miRNA-200c correlated significantly with large tumour size (p=0.03) and poor differentiation (p=0.03). Low miRNA-141 correlated significantly with large tumour size (p=0.02) and lymph node metastasis (p=0.04). Survival analysis revealed that patients with low miRNA-200c (p<0.05) and miRNA-141 expression (p=0.07) had shorter disease-free survival. There was a significant association of both miRNA-200c and miRNA-141 with E-cadherin and ZEB2 expression.

CONCLUSIONS

Low levels of miRNA-200c and miRNA-141 in patients with eyelid SGC facilitates tumour progression by promoting EMT and miRNA-200c has emerged as a novel potential predictor of survival.

Epithelial to Mesenchymal Transition in Renal Cell Carcinoma: Implications for Cancer Therapy

Epithelial-to-mesenchymal transition (EMT) is a developmentally vital reversible process by which fully differentiated cells lose their epithelial features and acquire a migratory mesenchymal phenotype. EMT contributes to the metastatic potential of tumors. The expression profile and other biological properties of EMT suggest potential targets for cancer therapy, including in renal-cell carcinoma (RCC). The preclinical and clinical results have substantiated the promises that dysregulated elements leading to EMT can be a potential target in RCC patients. In this study, we illustrated the pathogenic and prognostic role of EMT in RCC. In addition, we reconstructed, by literature analysis, the different pathways implicated in the EMT process, thus supporting the rational for future EMT-directed therapeutic approaches for RCC patients.

LncRNA MALAT1 functions as a competing endogenous RNA to regulate ZEB2 expression by sponging miR-200s in clear cell kidney carcinoma

Long non-coding RNA (lncRNAs) play a critical role in the development of cancers. LncRNA metastasis-associated lung adenocarcinoma transcript 1(MALAT1) has recently been identified to be involved in tumorigenesis of several cancers such as lung cancer, bladder cancer and so on. Here, we found that MALAT1 exist a higher fold change (Tumor/Normal) in clear cell kidney carcinoma (KIRC) from The Cancer Genome Atlas (TCGA) Data Portal and a negative correlation with miR-200s family. We further demonstrated MALAT1 promote KIRC proliferation and metastasis through sponging miR-200s in vitro and in vivo. In addition, miR-200c can partly reverse the MALAT1's stimulation on proliferation and metastasis in KIRC. In summary we unveil a branch of the MALAT1/miR-200s/ZEB2 pathway that regulates the progression of KIRC. The inhibition of MALAT1 expression may be a promising strategy for KIRC therapy.

MiR-429 is linked to metastasis and poor prognosis in renal cell carcinoma by affecting epithelial-mesenchymal transition

MicroRNAs (miRNAs) have been proven to be important oncogenes and tumor suppressors in wide range of cancers, including renal cell carcinoma (RCC). In our study, we evaluated miRNA-429 as potential diagnostic/prognostic biomarker in 172 clear cell RCC patients and as a potential regulator of epithelial-mesenchymal transition (EMT) in vitro. We demonstrated that miR-429 is down-regulated in tumor tissue samples (P < 0.0001) and is significantly associated with cancer metastasis (P < 0.0001), shorter disease-free (P = 0.0105), and overall survival (P = 0.0020). In addition, ectopic expression of miR-429 in 786-0 RCC cells followed by TGF-β treatment led to increase in the levels of E-cadherin expression (P < 0.0001) and suppression of cellular migration (P < 0.0001) in comparison to TGF-β-treated controls. Taken together, our findings suggest that miR-429 may serve as promising diagnostic and prognostic biomarker in RCC patients. We further suggest that miR-429 has a capacity to inhibit loss of E-cadherin in RCC cells undergoing EMT and consequently attenuate their motility.

Epithelial-mesenchymal transition-associated microRNA/mRNA signature is linked to metastasis and prognosis in clear-cell renal cell carcinoma

Clear-cell renal cell carcinomas (ccRCCs) are genetically heterogeneous tumors presenting diverse clinical courses. Epithelial-mesenchymal transition (EMT) is a crucial process involved in initiation of metastatic cascade. The aim of our study was to identify an integrated miRNA/mRNA signature associated with metastasis and prognosis in ccRCC through targeted approach based on analysis of miRNAs/mRNAs associated with EMT. A cohort of 230 ccRCC was included in our study and further divided into discovery, training and validation cohorts. EMT markers were evaluated in ccRCC tumor samples, which were grouped accordingly to EMT status. By use of large-scale miRNA/mRNA expression profiling, we identified miRNA/mRNA with significantly different expression in EMT-positive tumors and selected 41 miRNAs/mRNAs for training phase of the study to evaluate their diagnostic and prognostic potential. Fifteen miRNAs/mRNAs were analyzed in the validation phase, where all evaluated miRNA/mRNA candidates were confirmed to be significantly deregulated in tumor tissue. Some of them significantly differed in metastatic tumors, correlated with clinical stage, with Fuhrman grade and with overall survival. Further, we established an EMT-based stage-independent prognostic scoring system enabling identification of ccRCC patients at high-risk of cancer-related death. Finally, we confirmed involvement of miR-429 in EMT regulation in RCC cells in vitro.

Aberrantly expressed microRNAs in bladder cancer and renal cell carcinoma

Bladder cancer (BC) and renal cell carcinoma (RCC) are frequently diagnosed urinary tract cancers. Recently developed molecular-targeted therapies for RCC have shown remarkable therapeutic efficacy; however, no targeted therapeutics are currently approved for the treatment of BC, and few effective treatment options exist. Current studies have shown that small noncoding RNA molecules have major roles in cancer cells. MicroRNAs (miRNAs) are endogenous small noncoding RNA molecules that regulate protein-/nonprotein-coding RNAs in human cells. A large body of evidence suggests that aberrantly expressed miRNAs are deeply involved in the pathogenesis of human cancers. In this paper, we review recently published miRNA expression signatures of BC and RCC. We focus on downregulated or upregulated miRNAs in multiple signatures and discuss putative target genes of miRNAs. Comparisons of RCC and BC expression signatures revealed that the two types of cancer showed opposite expression patterns for miR-200 family miRNAs (i.e., miR-141/200c and miR-200a/200b/429). We discuss in silico analysis of genes targeted by miR-200 family miRNAs and the molecular mechanisms underlying BC and RCC.

Cooperative Effect of miR-141-3p and miR-145-5p in the Regulation of Targets in Clear Cell Renal Cell Carcinoma

Background

Due to the poor prognosis for advanced renal cell carcinoma (RCC), there is an urgent need for new therapeutic targets and for prognostic markers to identify high risk tumors. MicroRNAs (miRNAs) are frequently dysregulated in tumors, play a crucial role during carcinogenesis and therefore might be promising new biomarkers. In previous studies, we identified miR-141-3p and miR-145-5p to be downregulated in clear cell RCC (ccRCC). Our objective was to investigate the functional association of these miRNAs, focusing on the cooperative regulation of new specific targets and their role in ccRCC progression.

Methods

The effect of miR-141-3p and miR-145-5p on cell migration was examined by overexpression in 786-O cells. New targets of both miRNAs were identified by miRWalk, validated in 786-O and ACHN cells and additionally characterized in ccRCC tissue on mRNA and protein level.

Results

In functional analysis, a tumor suppressive effect of miR-141-3p and miR-145-5p by decreasing migration and invasion of RCC cells could be shown. Furthermore, co-overexpression of the miRNAs seemed to result in an increased inhibition of cell migration. Both miRNAs were recognized as post-transcriptional regulators of the targets EAPP, HS6ST2, LOX, TGFB2 and VRK2. Additionally, they showed a cooperative effect again as demonstrated by a significantly increased inhibition of HS6ST2 and LOX expression after simultaneous overexpression of both miRNAs. In ccRCC tissue, LOX mRNA expression was strongly increased compared to normal tissue, allowing also to distinguish between non-metastatic and already metastasized primary tumors. Finally, in subsequent tissue microarray analysis LOX protein expression showed a prognostic relevance for the overall survival of ccRCC patients.

Conclusion

These results illustrate a jointly strengthening effect of the dysregulated miR-141-3p and miR-145-5p in various tumor associated processes. Focusing on the cooperative effect of miRNAs provides new opportunities for the development of therapeutic strategies and offers novel prognostic and diagnostic capabilities.

Tumour-suppressive miRNA-26a-5p and miR-26b-5p inhibit cell aggressiveness by regulating PLOD2 in bladder cancer

BACKGROUND

Previous studies have revealed that miR-26a-5p and miR-26b-5p act as tumour suppressors in various types of cancer tissues. Here, we aimed to investigate the functional roles of these miRNAs and to identify their regulatory targets in bladder cancer (BC).

METHODS

We performed functional assays in BC cells using transfection of mature microRNAs (miRNAs). In silico and luciferase reporter analyses were applied to identify target genes of these miRNAs. The overall survival (OS) of patients with BC was evaluated by the Kaplan-Meier method.

RESULTS

miR-26a-5p and miR-26b-5p were significantly downregulated in BC tissues. Restoration of these miRNAs inhibited cell migration and invasion in BC. The gene encoding procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a collagen crosslinking enzyme, was directly regulated by miR-26a-5p and miR-26b-5p. Kaplan-Meier analysis revealed that patients with high PLOD2 expression had significantly shorter OS compared with those with low PLOD2 expression (P=0.0153).

CONCLUSIONS

PLOD2, which is associated with the stiffness of the extracellular matrix, was directly regulated by miR-26a-5p and miR-26b-5p and may be a good prognostic marker in patients with BC.

The miRacle in Pancreatic Cancer by miRNAs: Tiny Angels or Devils in Disease Progression

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with increasing incidence and high mortality. Surgical resection is the only potentially curative treatment of patients with PDAC. Because of the late presentation of the disease, about 20 percent of patients are candidates for this treatment. The average survival of resected patients is between 12 and 20 months, with a high probability of relapse. Standard chemo and radiation therapies do not offer significant improvement of the survival of these patients. Furthermore, novel treatment options aimed at targeting oncogenes or growth factors in pancreatic cancer have proved unsuccessful. Thereby, identifying new biomarkers that can detect early stages of this disease is of critical importance. Among these biomarkers, microRNAs (miRNAs) have supplied a profitable recourse and become an attractive focus of research in PDAC. MiRNAs regulate many genes involved in the development of PDAC through mRNA degradation or translation inhibition. The possibility of intervention in the molecular mechanisms of miRNAs regulation could begin a new generation of PDAC therapies. This review summarizes the reports describing miRNAs involvement in cellular processes involving pancreatic carcinogenesis and their utility in diagnosis, survival and therapeutic potential in pancreatic cancer.

Epigenomics of clear cell renal cell carcinoma: mechanisms and potential use in molecular pathology

Clear cell renal cell carcinoma (ccRCC) is one frequent form of urologic malignancy with numerous genetic and epigenetic alterations. This review summarizes the recent major findings of epigenetic alterations including DNA methylation, histone modifications, microRNAs and recently identified long noncoding RNAs in the development and progression of ccRCC. These epigenetic profilings can provide a promising means of prognostication and early diagnosis for patients with ccRCCs. With the developed high-throughput technologies nowadays, the epigenetic analyses will have possible clinical applications in the molecular pathology of ccRCC.

Combining miRNA and mRNA Expression Profiles in Wilms Tumor Subtypes

Wilms tumor (WT) is the most common childhood renal cancer. Recent findings of mutations in microRNA (miRNA) processing proteins suggest a pivotal role of miRNAs in WT genesis. We performed miRNA expression profiling of 36 WTs of different subtypes and four normal kidney tissues using microarrays. Additionally, we determined the gene expression profile of 28 of these tumors to identify potentially correlated target genes and affected pathways. We identified 85 miRNAs and 2107 messenger RNAs (mRNA) differentially expressed in blastemal WT, and 266 miRNAs and 1267 mRNAs differentially expressed in regressive subtype. The hierarchical clustering of the samples, using either the miRNA or mRNA profile, showed the clear separation of WT from normal kidney samples, but the miRNA pattern yielded better separation of WT subtypes. A correlation analysis of the deregulated miRNA and mRNAs identified 13,026 miRNA/mRNA pairs with inversely correlated expression, of which 2844 are potential interactions of miRNA and their predicted mRNA targets. We found significant upregulation of miRNAs-183, -301a/b and -335 for the blastemal subtype, and miRNAs-181b, -223 and -630 for the regressive subtype. We found marked deregulation of miRNAs regulating epithelial to mesenchymal transition, especially in the blastemal subtype, and miRNAs influencing chemosensitivity, especially in regressive subtypes. Further research is needed to assess the influence of preoperative chemotherapy and tumor infiltrating lymphocytes on the miRNA and mRNA patterns in WT.

Regulation of the collagen cross-linking enzymes LOXL2 and PLOD2 by tumor-suppressive microRNA-26a/b in renal cell carcinoma

Our recent studies of microRNA (miRNA) expression signatures in human cancers revealed that microRNA-26a (miRNA-26a) and microRNA-26b (miRNA-26b) were significantly reduced in cancer tissues. To date, few reports have provided functional analyses of miR-26a or miR-26b in renal cell carcinoma (RCC). The aim of the present study was to investigate the functional significance of miR-26a and miR-26b in RCC and to identify novel miR-26a/b-mediated cancer pathways and target genes involved in RCC oncogenesis and metastasis. Downregulation of miR-26a or miR-26b was confirmed in RCC clinical specimens. Restoration of miR-26a or miR-26b in RCC cell lines (786-O and A498) revealed that these miRNAs significantly inhibited cancer cell migration and invasion. Our in silico analysis and luciferase reporter assays showed that lysyl oxidase-like 2 (LOXL2) and procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) were directly regulated by these miRNAs. Moreover, downregulating the PLOD2 gene significantly inhibited cell migration and invasion in RCC cells. Thus, our data showed that two genes promoting metastasis, LOXL2 and PLOD2, were epigenetically regulated by tumor-suppressive microRNAs, miR-26a and miR-26b, providing important insights into the molecular mechanisms of RCC metastasis.

MicroRNAs in the Pathogenesis of Renal Cell Carcinoma and Their Diagnostic and Prognostic Utility as Cancer Biomarkers

Purpose

To provide information about the role of microRNAs in the pathogenesis of renal cell carcinoma (RCC) and their diagnostic and prognostic utility as cancer biomarkers.

Methods

A literature search was performed in the PubMed and Web of Science databases using the keywords “renal cancer/renal cell carcinoma/kidney cancer” and “miR*/miRNA*/microRNA*”. Articles dealing with the role of miRNAs in the pathogenesis of RCC, diagnostic miRNAs and prognostic miRNAs were separated.

Results

MiRNAs act both as oncogenes and tumor suppressors. They regulate apoptosis, cell growth, migration, invasion, proliferation, colony formation and angiogenesis through target proteins involved in several signaling pathways, and they are involved in key pathogenetic mechanisms such as hypoxia (HIF/VHL dependent) and epithelial-to-mesenchymal transition. Differentially expressed miRNAs can discriminate either tumor tissue from healthy renal tissue or different RCC subtypes. Circulating miRNAs are promissing as diagnostic biomarkers of RCC. Information about urinary miRNAs associated with RCC is sparse. Detection of a relapse is another implication of diagnostic miRNAs. The expression profiles of several miRNAs correlate with the prognosis of RCC patients. Comparison between primary tumor tissue and metastasis may help identify high-risk primary tumors. Finally, response to target therapy can be estimated thanks to differences in miRNA expression in tissue and serum of therapy-resistant versus therapy-sensitive patients.

Conclusions

Our understanding of the role of microRNAs in RCC pathogenesis has been increasing dramatically. Identification and validation of their gene targets may have direct impact on developing microRNA-based anticancer therapy. Several microRNAs can serve as diagnostic and prognostic biomarkers.

miR-206 functions as a novel cell cycle regulator and tumor suppressor in clear-cell renal cell carcinoma

PURPOSE

In this study we tried to systematically investigate the tumor suppressing microRNAs in ccRCC.

MATERIALS AND METHODS

The MTS cell viability and colony formation assay were used to systematically detect the tumor suppressing ability of down-regulated miRNAs in ccRCC. Then miR-206 expression was detected by RT-qPCR and in situ hybridization in ccRCC cell lines and clinical samples. Oligonucleotides were used to overexpress or down-regulate miR-206. MTS cell viability, EdU cell proliferation, colony formation assay, flow cytometry, Xenograft subcutaneously and orthotopic implantations were done to examine tumor suppressing effects of miR-206 in vitro and in vivo. Luciferase assay was performed to verify the precise target of miR-206.

RESULTS

We reviewed and experimentally analyzed the currently available miRNA expression profiles data of ccRCC and identified miR-206 as one of the most critical tumor-suppressing microRNAs in ccRCC. In addition, miR-206 inhibited ccRCC cell proliferation through inducing cell cycle arrest by directly targeting cell cycle related gene CDK4, CDK9 and CCND1.

CONCLUSIONS

All these results suggested that miR-206 functioned as a novel cell cycle regulator and tumor suppressor in ccRCC and could be considered as a potential target for ccRCC therapy.

Molecular mechanisms of microRNAs in regulating epithelial-mesenchymal transitions in human cancers

The epithelial-mesenchymal transition (EMT) provides a strong driving force in the progression of various human cancers and the development of chemoresistance. Recently, numbers of studies have demonstrated that microRNAs (miRNAs), by post-transcriptionally silencing EMT-related molecules, can promote or inhibit the EMT process and play pivotal roles in effectively manipulating the occurrence, development, invasion, and metastasis of cancers. MiRNAs can also control the EMT or be controlled by genetic modification and mutual regulation, especially negative feedback. Therefore, miRNAs can be viewed as either oncogenes or tumor suppressor genes to facilitate or retard the EMT, resulting in far-reaching impact on tumor metastasis and effective diagnosis, treatment, and prognosis.

Transcription Factor Hepatocyte Nuclear Factor-1β (HNF-1β) Regulates MicroRNA-200 Expression through a Long Noncoding RNA

The transcription factor hepatocyte nuclear factor-1β (HNF-1β) regulates tissue-specific gene expression in the kidney and other epithelial organs. Mutations of HNF-1β produce kidney cysts, and previous studies have shown that HNF-1β regulates the transcription of cystic disease genes, including Pkd2 and Pkhd1. Here, we combined chromatin immunoprecipitation and next-generation sequencing (ChIP-Seq) with microarray analysis to identify microRNAs (miRNAs) that are directly regulated by HNF-1β in renal epithelial cells. These studies identified members of the epithelial-specific miR-200 family (miR-200b/200a/429) as novel transcriptional targets of HNF-1β. HNF-1β binds to two evolutionarily conserved sites located 28 kb upstream to miR-200b. Luciferase reporter assays showed that the HNF-1β binding sites were located within a promoter that was active in renal epithelial cells. Mutations of the HNF-1β binding sites abolished promoter activity. RT-PCR analysis revealed that a long noncoding RNA (lncRNA) is transcribed from the promoter and encodes the miR-200 cluster. Inhibition of the lncRNA with siRNAs decreased the levels of miR-200 but did not affect expression of the Ttll10 host gene. The expression of the lncRNA and miR-200 was decreased in kidneys from HNF-1β knock-out mice and renal epithelial cells expressing dominant-negative mutant HNF-1β. The expression of miR-200 targets, Zeb2 and Pkd1, was increased in HNF-1β knock-out kidneys and in cells expressing mutant HNF-1β. Overexpression of miR-200 decreased the expression of Zeb2 and Pkd1 in HNF-1β mutant cells. These studies reveal a novel pathway whereby HNF-1β directly contributes to the control of miRNAs that are involved in epithelial-mesenchymal transition and cystic kidney disease.

Tumour-suppressive microRNA-144-5p directly targets CCNE1/2 as potential prognostic markers in bladder cancer

BACKGROUND

Analysis of a microRNA (miRNA) expression signature of bladder cancer (BC) by deep-sequencing revealed that clustered miRNAs microRNA (miR)-451a, miR-144-3p, and miR-144-5p were significantly downregulated in BC tissues. We hypothesised that these miRNAs function as tumour suppressors in BC. The aim of this study was to investigate the functional roles of these miRNAs and their modulation of cancer networks in BC cells.

METHODS

The functional studies of BC cells were performed using transfection of mature miRNAs. Genome-wide gene expression analysis, in silico analysis, and dual-luciferase reporter assays were applied to identify miRNA targets. The association between miR-144-5p levels and expression of the target genes was determined, and overall patient survival as a function of target gene expression was estimated by the Kaplan-Meier method.

RESULTS

Gain-of-function studies showed that miR-144-5p significantly inhibited cell proliferation by BC cells. Four cell cycle-related genes (CCNE1, CCNE2, CDC25A, and PKMYT1) were identified as direct targets of miR-144-5p. The patients with high CCNE1 or CCNE2 expression had lower overall survival probabilities than those with low expression (P=0.025 and P=0.032).

CONCLUSION

miR-144-5p functions as tumour suppressor in BC cells. CCNE1 and CCNE2 were directly regulated by miR-144-5p and might be good prognostic markers for survival of BC patients.

Functional genomics identifies novel genes essential for clear cell renal cell carcinoma tumor cell proliferation and migration

Currently there is a lack of targeted therapies that lead to long-term attenuation or regression of disease in patients with advanced clear cell renal cell carcinoma (ccRCC). Our group has implemented a high-throughput genetic analysis coupled with a high-throughput proliferative screen in order to investigate the genetic contributions of a large cohort of overexpressed genes at the functional level in an effort to better understand factors involved in tumor initiation and progression.

Patient gene array analysis identified transcripts that are consistently elevated in patient ccRCC as compared to matched normal renal tissues. This was followed by a high-throughput lentivirus screen, independently targeting 195 overexpressed transcripts identified in the gene array in four ccRCC cell lines. This revealed 31 ‘hits’ that contribute to ccRCC cell proliferation.

Many of the hits identified are not only presented in the context of ccRCC for the first time, but several have not been previously linked to cancer. We further characterize the function of a group of hits in tumor cell invasion. Taken together these findings reveal pathways that may be critical in ccRCC tumorigenicity, and identifies novel candidate factors that could serve as targets for therapeutic intervention or diagnostic/prognostic biomarkers for patients with advanced ccRCC.

MicroRNA-429 suppresses cell proliferation, epithelial-mesenchymal transition, and metastasis by direct targeting of BMI1 and E2F3 in renal cell carcinoma

BACKGROUND

MicroRNA-429 (miR-429), a short noncoding RNA belonging to the miR-200 superfamily, plays a crucial role in tumorigenesis and tumor progression. It also acts as a modulator of epithelial-to-mesenchymal transition, a cell development regulating process that affects tumor development and metastasis. The aim of this study was to investigate the potential role of miR-429 in regulating growth and metastasis of renal cell carcinoma.

METHODS

miR-429 expression was stably up-regulated or down-regulated in the renal cell carcinoma ACHN and A498 cell lines, and cell proliferation and metastasis were assessed.

RESULTS

miR-429 overexpression inhibited cell proliferation, colony formation, migration, and invasion. Suppression of endogenous miR-429 promoted cell growth and metastasis. miR-429 was shown to directly target the 3' untranslated regions of B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) and E2F transcription factor 3 (E2F3) transcripts, regulating their expression, as well as that of the downstream epithelial-to-mesenchymal transition markers E-cadherin, N-cadherin, vimentin, p14, and p16.

CONCLUSIONS

These results revealed a tumor suppressive role for miR-429 in renal cell carcinoma through directly targeting BMI1 and E2F3.

Tumor suppressive microRNA-200a inhibits renal cell carcinoma development by directly targeting TGFB2

A large body of evidence indicates that microRNAs play a critical role in tumor initiation and progression by negatively regulating oncogenes or tumor suppressor genes. Here, we report that the expression of miR-200a was notably downregulated in 45 renal cell carcinoma (RCC) samples. Restoration of miR-200a suppressed cell proliferation, migration, and invasion in two RCC cell lines. Furthermore, we used an epithelial-to-mesenchymal transition PCR array to explore the putative target genes of miR-200a. By performing quantitative real-time PCR, ELISA, and luciferase reporter assays, transforming growth factor beta2 (TGFB2) was validated as a direct target gene of miR-200a. Moreover, siRNA-mediated knockdown of TGFB2 partially phenocopied the effect of miR-200a overexpression. These results suggest that miR-200a suppresses RCC development via directly targeting TGFB2, indicating that miR-200a may present a novel target for diagnostic and therapeutic strategies in RCC.