MicroRNA-221 silencing predisposed human bladder cancer cells to undergo apoptosis induced by TRAIL

TRAIL-mediated signaling in bladder cancer: realization of clinical efficacy of TRAIL-based therapeutics in medical oncology

Bladder cancer is a therapeutically challenging disease and wealth of knowledge has enabled researchers to develop a clear understanding of mechanisms which underlie carcinogenesis and metastasis. Excitingly, research over decades has unveiled wide-ranging mechanisms which serve as central engine in progression of bladder cancer. Loss of apoptosis, drug resistance, and pro-survival signaling are some of the highly studied cellular mechanisms. Therefore, restoration of apoptosis in resistant cancers is a valuable and attractive strategy. Discovery of TRAIL-mediated signaling cascade is an intriguing facet of molecular oncology. In this review, we have provided an overview of the translational and foundational advancements in dissecting the genomic and proteomic cartography of TRAIL signaling exclusively in the context of bladder cancer. We have also summarized how different natural products sensitized drug-resistant bladder cancer cells to TRAIL-mediated apoptosis. Interestingly, different death receptors that activate agonistic antibodies have been tested in various phases of clinical trials against different cancers. Certain clues of scientific evidence have provided encouraging results about efficacy of these agonistic antibodies (lexatumumab and mapatumumab) against bladder cancer cell lines. Therefore, multipronged approaches consisting of natural products, chemotherapeutics, and agonistic antibodies will realistically and mechanistically provide proof-of-concept for the translational potential of these combinatorial strategies in well-designed clinical trials.

Apoptosis evasion via long non-coding RNAs in colorectal cancer

Long non-coding RNA (LncRNA) is a novel and diverse class of regulatory transcripts that are frequently dysregulated in numerous tumor types. LncRNAs are involved in a complicated molecular network, regulating gene expression, and modulating diverse cellular activities in different cancers including colorectal cancer (CRC). Evidence indicates that lncRNAs can be used as a potential biomarker for the prognosis and diagnosis of CRC as they are aberrantly expressed in CRC cells. The high expression or silencing of lncRNAs is associated with cell proliferation, invasion, metastasis, chemoresistance and apoptosis in CRC. LncRNAs exert both pro-apoptotic and anti-apoptotic functions in CRC. The expression of some oncogene lncRNAs is upregulated which leads to the inhibition of apoptotic pathways, similarly, the tumor suppressor lncRNAs are downregulated in CRC. In this review, we describe the function and mechanisms of lncRNAs to regulate the expression of genes that are involved directly or indirectly in controlling cellular apoptosis in CRC. Furthermore, we also discussed the different apoptotic pathways in normal cells and the mechanisms by which CRC evade apoptosis.

The paradigm of drug resistance in cancer: an epigenetic perspective

Innate and acquired resistance towards the conventional therapeutic regimen imposes a significant challenge for the successful management of cancer for decades. In patients with advanced carcinomas, acquisition of drug resistance often leads to tumor recurrence and poor prognosis after the first therapeutic cycle. In this context, cancer stem cells (CSCs) are considered as the prime drivers of therapy resistance in cancer due to their 'non-targetable' nature. Drug resistance in cancer is immensely influenced by different properties of CSCs such as epithelial-to-mesenchymal transition (EMT), a profound expression of drug efflux pump genes, detoxification genes, quiescence, and evasion of apoptosis, has been highlighted in this review article. The crucial epigenetic alterations that are intricately associated with regulating different mechanisms of drug resistance, have been discussed thoroughly. Additionally, special attention is drawn towards the epigenetic mechanisms behind the interaction between the cancer cells and their microenvironment which assists in tumor progression and therapy resistance. Finally, we have provided a cumulative overview of the alternative treatment strategies and epigenome-modifying therapies that show the potential of sensitizing the resistant cells towards the conventional treatment strategies. Thus, this review summarizes the epigenetic and molecular background behind therapy resistance, the prime hindrance of present day anti-cancer therapies, and provides an account of the novel complementary epi-drug-based therapeutic strategies to combat drug resistance.

Epigenetic Deregulation of Apoptosis in Cancers

Cancer cells possess the ability to evade apoptosis. Genetic alterations through mutations in key genes of the apoptotic signaling pathway represent a major adaptive mechanism of apoptosis evasion. In parallel, epigenetic changes via aberrant modifications of DNA and histones to regulate the expression of pro- and antiapoptotic signal mediators represent a major complementary mechanism in apoptosis regulation and therapy response. Most epigenetic changes are governed by the activity of chromatin modifying enzymes that add, remove, or recognize different marks on histones and DNA. Here, we discuss how apoptosis signaling components are deregulated at epigenetic levels, particularly focusing on the roles of chromatin-modifying enzymes in this process. We also review the advances in cancer therapies with epigenetic drugs such as DNMT, HMT, HDAC, and BET inhibitors, as well as their effects on apoptosis modulation in cancer cells. Rewiring the epigenome by drug interventions can provide therapeutic advantage for various cancers by reverting therapy resistance and leading cancer cells to undergo apoptotic cell death.

Non-coding RNA in bladder cancer

Bladder cancer is the tenth most common cancer worldwide and has been associated with high mortality and morbidity. Although the treatment of bladder cancer is based on well-defined tumor classifications and gradings, patients still experience different clinical response. The heterogeneity of this disease calls for substantial research with more in-depth molecular characterization, with the hope of identifying new diagnostic and treatment options. In recent years, non-coding RNAs (ncRNAs), particularly, microRNAs (miRNAs), long non-coding RNA (lncRNAs), and circular RNAs (circRNAs) were found to be associated with bladder cancer occurrence and development. This review highlights the recent findings concerning ncRNAs and their relevance to the pathogenesis of bladder cancer. This may provide a foundation for developing highly specific diagnostic tools and more robust therapeutic strategies in the future.

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.

miRNAs: A Promising Target in the Chemoresistance of Bladder Cancer

Chemotherapy is an important cancer treatment method. Tumor chemotherapy resistance is one of the main factors leading to tumor progression. Like other malignancies, bladder cancer, especially muscle-invasive bladder cancer, is prone to chemotherapy resistance. Additionally, only approximately 50% of muscle-invasive bladder cancer responds to cisplatin-based chemotherapy. miRNAs are a class of small, endogenous, noncoding RNAs that regulate gene expression at the posttranscriptional level, which results in the inhibition of translation or the degradation of mRNA. In the study of miRNAs and cancer, including gastric cancer, prostate cancer, liver cancer, and colorectal cancer, it has been found that miRNAs can regulate the expression of genes related to tumor resistance, thereby promoting the progression of tumors. In bladder cancer, miRNAs are also closely related to chemotherapy resistance, suggesting that miRNAs can be a new therapeutic target for the chemotherapy resistance of bladder cancer. Therefore, understanding the mechanisms of miRNAs in the chemotherapy resistance of bladder cancer is an important foundation for restoring the chemotherapy sensitivity of bladder cancer and improving the efficacy of chemotherapy and patient survival. In this article, we review the role of miRNAs in the development of chemotherapy-resistant bladder cancer and the various resistance mechanisms that involve apoptosis, the cell cycle, epithelial-mesenchymal transition (EMT), and cancer stem cells (CSCs).

miR-221 Augments TRAIL-Mediated Apoptosis in Prostate Cancer Cells by Inducing Endogenous TRAIL Expression and Targeting the Functional Repressors SOCS3 and PIK3R1

miR-221 is regarded as an oncogene in many malignancies, and miR-221-mediated resistance towards TRAIL was one of the first oncogenic roles shown for this small noncoding RNA. In contrast, miR-221 is downregulated in prostate cancer (PCa), thereby implying a tumour suppressive function. By using proliferation and apoptosis assays, we show a novel feature of miR-221 in PCa cells: instead of inducing TRAIL resistance, miR-221 sensitized cells towards TRAIL-induced proliferation inhibition and apoptosis induction. Partially responsible for this effect was the interferon-mediated gene signature, which among other things contained an endogenous overexpression of the TRAIL encoding gene TNFSF10. This TRAIL-friendly environment was provoked by downregulation of the established miR-221 target gene SOCS3. Moreover, we introduced PIK3R1 as a target gene of miR-221 in PCa cells. Proliferation assays showed that siRNA-mediated downregulation of SOCS3 and PIK3R1 mimicked the effect of miR-221 on TRAIL sensitivity. Finally, Western blotting experiments confirmed lower amounts of phospho-Akt after siRNA-mediated downregulation of PIK3R1 in PC3 cells. Our results further support the tumour suppressing role of miR-221 in PCa, since it sensitises PCa cells towards TRAIL by regulating the expression of the oncogenes SOCS3 and PIK3R1. Given the TRAIL-inhibiting effect of miR-221 in various cancer entities, our results suggest that the influence of miR-221 on TRAIL-mediated apoptosis is highly context- and entity-dependent.

MicroRNAs: Key Players in Bladder Cancer

Bladder cancer (BC) is the second highest morbid malignancy of the urinary tract and the fifth most common cancer worldwide. BC is highly malignant with significant morbidity and mortality, especially muscle-invasive BC (MIBC), which has a poor prognosis and frequently recurs after the first resection. Therefore, more sensitive diagnostic tools and effective therapeutic methods are urgently needed. MicroRNAs (miRNAs) are small noncoding RNAs that regulate the expression of protein-coding genes by repressing their translation or cleaving RNA transcripts in a sequence-specific manner. miRNAs play very important roles in regulating genes related to tumorigenesis, tumor development, progression, metastasis and angiogenesis. With the rapid development of high-throughput sequencing technology, an increasing number of miRNAs with aberrant expression between either BC patients and healthy volunteers or between BC tumor tissues and matched peripheral control tissues have been recently examined. The tumor etiopathogenesis must be determined to promote the development of new markers as diagnostic and prognostic tools and targets for bladder tumor therapy, it is therefore vital to elucidate the function of miRNAs with aberrant expression in BC. In the present study, we examined the published data of BC-related miRNAs by reviewing their expression levels, possible functions, potential target genes, related molecular regulatory networks, candidate markers for prognosis and diagnosis, and prospective therapeutic cases, and we summarized the status of research on BC-related miRNAs in recent years.

Generic Neutravidin Biosensor for Simultaneous Multiplex Detection of MicroRNAs via Electrochemically Encoded Responsive Nanolabels

Current electrochemical biosensors for multiple miRNAs require tedious immobilization of various nucleic acid probes. Here, we demonstrate an innovative approach using a generic neutravidin biosensor combined with electrochemically encoded responsive nanolabels for facile and simultaneous multiplexed detection of miRNA-21 and miRNA-141. The selectivity of the biosensor arises from the intrinsic properties of the electrochemically encoded responsive nanolabels, comprising biotinylated molecular beacons (biotin-MB) and metal nanoparticles (metal-NPs). The procedure is a simple one-pot assay, where the targeted miRNA causes the opening of biotin-MB followed by capturing of the biotin-MB-metal-NPs by the neutravidin biosensor and simultaneous detection of the captured metal-NPs by stripping square-wave voltammetry (SSWV). The multiplexed detection of miRNA-21 and miRNA-141 is achieved by differentiation of the electrochemical signature (i.e., the peak current) for the different metal-NP labels. The biosensor delivers simultaneous detection of miRNAs with a linear range of 0.5-1000 pM for miRNA-21 and a limit of detection of 0.3 pM (3σ/sensitivity,  n = 3), and a range of 50-1000 pM for miRNA-141, with a limit of detection of 10 pM. Furthermore, we demonstrate multiplexed detection of miRNA-21 and miRNA-141 in a spiked serum sample.

MicroRNA-940 Targets INPP4A or GSK3β and Activates the Wnt/β-Catenin Pathway to Regulate the Malignant Behavior of Bladder Cancer Cells

In this report, we aimed to explore the role and regulatory mechanism of microRNA-940 (miR-940) in bladder cancer development. The expressions of miR-940 in bladder cancer tissues and cells were measured. miR-940 mimics, miR-940 inhibitor small interference RNA against INPP4A (si-INPP4A), and GSK3β (si-GSK3β) and their corresponding controls were then transfected into cells. We investigated the effects of miR-940, INPP4A, or GSK3β on cell proliferation, migration, invasion, and apoptosis. Additionally, target prediction and luciferase reporter assays were performed to investigate the targets of miR-940. The regulatory relationship between miR-940 and the Wnt/β-catenin pathway was also investigated. miR-940 was upregulated in bladder cancer tissues and cells. Overexpression of miR-940 significantly increased bladder cancer cell proliferation, promoted migration and invasion, and inhibited cell apoptosis. INPP4A and GSK3β were the direct targets of miR-940, and knockdown of INPP4A or GSK3β significantly increased cancer cell proliferation, migration, and invasion and inhibited cell apoptosis. After miR-940 overexpression, the protein expression levels of c-Myc, cyclin D1, and β-catenin were significantly increased, and the expression levels of p27 and p-β-catenin were markedly decreased. The opposite effects were obtained after suppression of miR-940. XAV939, a tankyrase 1 inhibitor that could inhibit Wnt/β-catenin signaling, significantly reversed the effects of miR-940 overexpression on cell migration and invasion. Our results indicate that overexpression of miR-940 may promote bladder cancer cell proliferation, migration, and invasion and inhibit cell apoptosis via targeting INPP4A or GSK3β and activating the Wnt/β-catenin pathway. Our findings imply the key roles of suppressing miRNA-940 in the therapy of bladder cancer.

Inflammatory microenvironment in the initiation and progression of bladder cancer

Accumulating evidence suggests the idea that chronic inflammation may play a critical role in various malignancies including bladder cancer and long-term treatment with non-steroidal anti-inflammatory drugs (NSAIDs) is significantly effective in reducing certain cancer incidence and mortality. However, the molecular mechanisms leading to malignant transformation and the progression of bladder cancer in a chronically inflammatory environment remain largely unknown. In this review, we will describe the role of inflammation in the formation and development of bladder cancer and summarize the possible molecular mechanisms by which chronic inflammation regulates cell immune response, proliferation and metastasis. Understanding the novel function orchestrating inflammation and bladder cancer will hopefully provide us insights into their future clinical significance in preventing bladder carcinogenesis and progression.

Clinical potential of miRNA-221 as a novel prognostic biomarker for hepatocellular carcinoma

miRNA-221 is one of the over 700 kinds of currently known microRNAs (miRNAs) and is up-regulated in multiple tumors, suggesting that it may be a potential carcinogenic miRNA. Few studies have explored the relationship between miRNA-221 and hepatocellular carcinoma (HCC). We performed real-time quantitative polymerase chain reaction (qPCR) to detect miRNA-221 expression in HCC and para-carcinoma tissues and to explore the relationship between abnormal expression of miRNA-221 and clinicopathological features of HCC patients. miRNA-221 expression was significantly higher in HCC tissues than in adjacent tissues (P < 0.001). We analyzed the relationship between miRNA-221 expression level and clinicopathological characteristics of HCC patients. Our results suggested that miRNA-221 expression level was closely related to tumor stage (P = 0.012), number of tumor nodes (P = 0.018), and microvascular invasion (P = 0.010) in HCC patients. The results of survival analysis suggested that HCC patients with up-regulated miRNA-221 expression had a shorter survival time. The high miRNA-221 expression indicates the poor prognosis of HCC patients; thus, miRNA-221 can be regarded an important molecular marker for HCC prognosis.

[Recent advances in bladder urothelial carcinogenesis]

Bladder cancer is the sixth cause of cancer mortality in France and prognosis of muscle-invasive tumors remains poor due to lack of effective treatments. Recent advances in molecular biology applied to tumors and results of recent genome-wide studies have brought a important impact on the understanding of bladder carcinogenesis. Main molecular alterations concern FGFR3, TP53 and HER2, and it is now possible to distinguish three subgroups of tumors according to molecular profile. This paper proposes a review of different genetic and epigenetic alterations in bladder cancer, their potential role as theranostic markers in clinical oncology and new targeted therapies according to the concept of personalized medicine.

miR-221 facilitates the TGFbeta1-induced epithelial-mesenchymal transition in human bladder cancer cells by targeting STMN1

Background

Distant metastasis is the major cause of cancer-related death, and epithelial-to-mesenchymal transition (EMT) has a critical role in this process. Accumulating evidence indicates that EMT can be regulated by microRNAs (miRNAs). miR-221, as oncogenes in several human cancers, was significantly up-regulated in bladder cancers. However, the role of miR-221 in the progression of bladder cancer metastasis remains largely unknown.

Methods

We used qRT-PCR and western blot to accurately measure the levels of miR-221, STMN1 and EMT markers in TGFβ1 induced EMT of bladder cancer cells. miR-221 inhibitors were re-introduced into bladder cancer cells to investigate its role on tumor metastasis which was measured by MTT, wound healing, transwell invasion and adherent assays. Luciferase reporter assay was used to reveal the target gene of miR-221.

Results

miR-221 expression was greatly increased by TGFβ1 in bladder cancer cell. miR-221 inhibition reversed TGFβ1 induced EMT by sharply increasing the expression of the epithelial marker E-cadherin and decreasing the expression of the mesenchymal markers vimentin, Fibroactin and N-cadherin. Furthermore, miR-221 expression is positively correlated with malignant potential of bladder cancer cell through promoting loss of cell adhesion and prometastatic behavior. Luciferase reporter assay revealed that miR-221 negatively regulates STMN1 expression by direct targeting to the 3′UTR region of STMN1.

Conclusions

Our study demonstrated that miR-221 facilitated TGFβ1-induced EMT in human bladder cancer cells by targeting STMN1 and represented a promising therapeutic target in the process of metastasis.

Systems analysis reveals down-regulation of a network of pro-survival miRNAs drives the apoptotic response in dilated cardiomyopathy

Apoptosis is a hallmark of multiple etiologies of heart failure, including dilated cardiomyopathy. Since microRNAs are master regulators of cardiac development and key effectors of intracellular signaling, they represent novel candidates for understanding the mechanisms driving the increased dysfunction and loss of cardiomyocytes during cardiovascular disease progression. To determine the role of cardiac miRNAs in the apoptotic response, we used microarray technology to monitor miRNA levels in a validated murine phospholambam mutant model of dilated cardiomyopathy. 24 miRNAs were found to be differentially expressed, most of which have not been previously linked to dilated cardiomyopathy. We showed that individual silencing of 7 out of 8 significantly down-regulated miRNAs (mir-1, -29c, -30c, -30d, -149, -486, -499) led to a strong apoptotic phenotype in cell culture, suggesting they repress pro-apoptotic factors. To identify putative miRNA targets most likely relevant to cell death, we computationally integrated transcriptomic, proteomic and functional annotation data. We showed the dependency of prioritized target abundance on miRNA expression using RNA interference and quantitative mass spectrometry. We concluded that down regulation of key pro-survival miRNAs causes up-regulation of apoptotic signaling effectors that contribute to cardiac cell loss, potentially leading to system decompensation and heart failure.

Antisense therapeutics in oncology: current status

There is increasing progress in translational oncology and tremendous breakthroughs have been made as evidenced by preclinical and clinical trials. Data obtained from high-throughput technologies are deepening our understanding about the molecular and gene network in cancer cells and rapidly emerging in vitro and in vivo evidence is highlighting the role of antisense agents as specific inhibitors of the expression of target genes, thus modulating the response of cancer cells to different therapeutic strategies. Much information is continuously being added into various facets of molecular oncology and it is now understood that overexpression of antiapoptotic proteins, oncogenes, oncogenic microRNAs (miRNA), and fusion proteins make cancer cells difficult to target. Delivery of antisense oligonucleotides has remained a challenge and technological developments have helped in overcoming hurdles by improving the ability to penetrate cells, effective and targeted binding to gene sequences, and downregulation of target gene function. Different delivery systems, including stable nucleic acid lipid particles, have shown potential in enhancing the delivery of cargo to the target site. In this review, we attempt to summarize the current progress in the development of antisense therapeutics and their potential in medical research. We partition this multicomponent review into introductory aspects about recent breakthroughs in antisense therapeutics. We also discuss how antisense therapeutics have shown potential in resensitizing resistant cancer cells to apoptosis by targeted inhibition of antiapoptotic proteins, oncogenic miRNAs, and BCR-ABL.

Expression patterns of miR-221 and its target Caspase-3 in different cancer cell lines

Caspases are important initiators and most well-known finishers of apoptosis. By changing the death propagation homeostatic equilibrium, their different expression patterns might trigger the progression of hazardous diseases like cancer. miR-221 is an oncogenic miRNA. It is known to have both anti-angiogenic and angiogenic effect. The aim of this work was to compare the expression levels of miR-221 and its target caspase-3 in different cancer cell lines and to find out a relationship between these two. We also tried to establish a prominent relationship between miR-221 and its role in apoptosis by studying their expression levels. Our results indicate that expression of caspase-3 is quite lower as compared to miR-221 expression in all of the selected cancer cell lines. As a result, we conclude that miR-221 may have a crucial role in repressing the expression of caspase-3 which may contribute to a lower apoptotic rate, thus supporting the selection of more aggressive cancer cells. To our knowledge, this is the first study related to the expression levels of caspase-3 and miR-221 in different cell lines at the same time. We expect that our study might pave the way for better understanding the role of miR-221 in apoptotic regulation of caspase-3.

Integrated gene network analysis and text mining revealing PIK3R1 regulated by miR-127 in human bladder cancer

BACKGROUND

Cancer is the result of a complex multistep process that involves the accumulation of sequential alterations of several genes, including those encoding microRNAs (miRNAs) that have critical roles in the regulation of gene expression.In this study, we aimed to predict potential mechanisms of bladder cancer related miRNAs and target genes by bioinformatics analyses.

METHODS

Here we used the method of text mining to identify nine miRNAs in bladder cancer and adopted protein-protein interaction analysis to identify interaction sites between these miRNAs and related-target genes.

RESULTS

There are two relationship types between bladder cancer and its related miRNAs: causal and unspecified. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment test showed that there were three pathways related to four miRNA targeted genes. The remaining five miRNAs annotated to disease are not enriched in the KEGG pathways. Of these, PIK3R1 is the overlapping gene among 38 genes in the cancer and bladder cancer pathways.

CONCLUSIONS

These findings provide new insights into the role of miRNAs in the pathway of cancer and give us a hypothesis that miR-127 might play a similar role in regulation and control of PIK3R1.

The evolving understanding of microRNA in bladder cancer

PURPOSE

Micro ribonucleic acid (miR) expression is altered in urologic malignancies, including bladder cancer (BC). Individual miRs have been shown to modulate multiple signaling pathways that contribute to BC. We reviewed the primary literature on the role of miRs in BC; we provide a general introduction to the processing, regulation, and function of miRs as tumor suppressors and oncogenes and critically evaluate the literature on the implications of altered miR expression in BC.

MATERIALS AND METHODS

We searched the English language literature for original and review articles in PubMed from 1993 to March 2013, using the terms "microRNA" and "bladder cancer," "transitional cell carcinoma," or "urothelial carcinoma." This search yielded 133 unique articles with more than 85% of them published within the last 3 years.

RESULTS

To date, the majority of miR studies in BC use profiling to describe dynamic changes in miR expression across stage and grade. Generalized down-regulation of miRs, including those that target the fibroblast growth factor 3 pathway, such as miR-145, miR-101, miR-100, and miR-99a, has been observed in low-grade, non-muscle invasive BC. In contrast, generalized increased expression of miRs is observed in high-grade, muscle-invasive BC compared with adjacent normal bladder urothelium, including miRs predicted to target p53, such as miR-21 and miR-373. Furthermore, p53 suppresses transcriptional factors that promote mesenchymal differentiation, ZEB-1 and ZEB-2, through regulation of the miR200 family.

CONCLUSIONS

Aberrations in miR expression identified between non-muscle invasive BC and muscle-invasive BC provide insight into the molecular alterations known to distinguish the two parallel pathways of bladder carcinogenesis. The heterogeneity of tumor specimens and research methods limits the reproducibility of changes in miR expression profiles between studies and underscores the importance of in vivo validation in a field that utilizes in silico miR target-prediction models.

Increased miR-221 expression in hepatocellular carcinoma tissues and its role in enhancing cell growth and inhibiting apoptosis in vitro

Background

MiR-221 is over-expressed in human hepatocellular carcinoma (HCC), but its clinical significance and function in HCC remains uncertain. The aim of the study was to investigate the relationship between miR-221 overexpression and clinicopathological parameters in HCC formalin-fixed paraffin-embedded (FFPE) tissues, and the effect of miR-221 inhibitor and mimic on different HCC cell lines in vitro.

Methods

MiR-221 expression was detected using real time RT-qPCR in FFPE HCC and the adjacent noncancerous liver tissues. The relationship between miR-221 level and clinicopathological features was also analyzed. Furthermore, miR-221 inhibitor and mimic were transfected into HCC cell lines HepB3, HepG2 and SNU449. The effects of miR-221 on cell growth, cell cycle, caspase activity and apoptosis were also investigated by spectrophotometry, fluorimetry, fluorescence microscopy and flow cytometry, respectively.

Results

The relative expression of miR-221 in clinical TNM stages III and IV was significantly higher than that in the stages I and II. The miR-221 level was also upregulated in the metastatic group compared to the nonmetastatic group. Furthermore, miR-221 over-expression was related to the status of tumor capsular infiltration in HCC clinical samples. Functionally, cell growth was inhibited, cell cycle was arrested in G1/S-phase and apoptosis was increased by miR-221 inhibitor in vitro. Likewise, miR-221 mimic accelerated the cell growth.

Conclusions

Expression of miR-221 in FFPE tissues could provide predictive significance for prognosis of HCC patients. Moreover, miR-221 inhibitor could be useful to suppress proliferation and induce apoptosis in HCC cells. Thus miR-221 might be a critical targeted therapy strategy for HCC.

miRNA-100 inhibits human bladder urothelial carcinogenesis by directly targeting mTOR

miRNAs are involved in cancer development and progression, acting as tumor suppressors or oncogenes. In this study, miRNA profiling was conducted on 10 paired bladder cancer tissues using 20 GeneChip miRNA Array, and 10 differentially expressed miRNAs were identified in bladder cancer and adjacent noncancerous tissues of any disease stage/grade. After being validated on expanded cohort of 67 paired bladder cancer tissues and 10 human bladder cancer cell lines by quantitative real-time PCR (qRT-PCR), it was found that miR-100 was downregulated most significantly in cancer tissues. Ectopic restoration of miR-100 expression in bladder cancer cells suppressed cell proliferation and motility, induced cell-cycle arrest in vitro, and inhibited tumorigenesis in vivo both in subcutaneous and in intravesical passage. Bioinformatic analysis showed that the mTOR gene was a direct target of miR-100. siRNA-mediated mTOR knockdown phenocopied the effect of miR-100 in bladder cancer cell lines. In addition, the cancerous metastatic nude mouse model established on the basis of primary bladder cancer cell lines suggested that miR-100/mTOR regulated cell motility and was associated with tumor metastasis. Both mTOR and p70S6K (downstream messenger) presented higher expression levels in distant metastatic foci such as in liver and kidney metastases than in primary tumor. Taken together, miR-100 may act as a tumor suppressor in bladder cancer, and reintroduction of this mature miRNA into tumor tissue may prove to be a therapeutic strategy by reducing the expression of target genes.

While at Rome miRNA and TRAIL do whatever BCR-ABL commands to do

It is a well-acclaimed fact that proteins expressed as a consequence of oncogenic fusions, mutations or amplifications can facilitate ectopic protein-protein interactions that re-wire signal dissemination pathways, in a manner that escalates malignancy. BCR-ABL-mediated signal transduction cascades in leukemic cells are assembled and modulated by a finely controlled network of protein-protein interactions, mediated by characteristic signaling domains and their respective binding motifs. BCR-ABL functions in a cell context-specific and cell type-specific manner to integrate signals that affect uncontrolled cellular proliferation. In this review, we draw attention to the recent progress made in outlining resistance against TRAIL-mediated apoptosis and diametrically opposed roles of miRNAs in BCR-ABL-positive leukemic cells. BCR-ABL governs carcinogenesis through well-organized web of antiapoptotic proteins and over-expressed oncomirs which target death receptors and pro-apoptotic genes. Set of oncomirs which inversely correlate with expression of TRAIL via suppression of SMAD is an important dimension which is gradually gaining attention of the researchers. Contrary to this, some current findings show a new role of BCR-ABL in nucleus with spotlight on apoptosis. It seems obvious that genetic heterogeneity of leukemias poses therapeutic challenges, and pharmacological agents that target components of the cancer promoting nano-machinery still need broad experimental validation to be considered competent as a component of the therapeutic arsenal for this group of diseases. Rapidly developing technologies are empowering us to explain the molecular "nature" of a patient and/or tumor and with this integration of personalized medicine, with maximized efficacy, cost effectiveness will hopefully improve survival chances of the patient.

Targeting microRNAs to modulate TRAIL-induced apoptosis of cancer cells

MicroRNAs (miRNAs) are endogenously expressed small non-coding RNAs, which are evolutionarily conserved and function as regulators of gene expression. These molecules are involved in numerous biological processes including differentiation, development, proliferation and apoptosis. Further investigation identifies that miRNAs may act as either potent oncogenes or tumor-suppressor genes, linking to cancer initiation and progression. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), as a member of the TNF family, is an attractive therapeutic target in cancer because it directly induces tumor cell apoptosis and has no cytotoxicity to normal cell types in vitro or in vivo. However, the resistance to TRAIL-induced apoptosis limits its clinical effectiveness. Interestingly, several studies convincingly demonstrate a role of miRNAs in modulating sensitive/resistant phenotypes to TRAIL. Here, we review the current findings about miRNAs involved in TRAIL-induced apoptosis in different cancers.

The role of microRNA-binding site polymorphisms in DNA repair genes as risk factors for bladder cancer and breast cancer and their impact on radiotherapy outcomes

MicroRNAs (miRNAs) are involved in post-transcriptional regulation of gene expression through binding to messenger RNAs (mRNA) thereby promoting mRNA degradation or altered translation. A single-nucleotide polymorphism (SNP) located within a miRNA-binding site could thus alter mRNA translation and influence cancer risk and treatment response. The common SNPs located within the 3'-untranslated regions of 20 DNA repair genes were analysed for putative miRNA-binding sites using bioinformatics algorithms, calculating the difference in Gibbs free binding energy (ΔΔG) for each wild-type versus variant allele. Seven SNPs were selected to be genotyped in germ line DNAs both from a bladder cancer case-control series (752 cases and 704 controls) and 202 muscle-invasive bladder cancer radiotherapy cases. The PARP-1 SNP rs8679 was also genotyped in a breast cancer case-control series (257 cases and 512 controls). Without adjustment for multiple testing, multivariate analysis demonstrated an association with increased bladder cancer risk with PARP1 rs8679 (P(trend) = 0.05) while variant homozygotes of PARP1 rs8679 were also noted to have an increased breast cancer risk (P = 0.03). In the radiotherapy cases, carriers of the RAD51 rs7180135 minor allele had improved cancer-specific survival (hazard ratio 0.52, 95% confidence interval 0.31-0.87, P = 0.01). This is the first report of associations between DNA repair gene miRNA-binding site SNPs with bladder and breast cancer risk and radiotherapy outcomes. If validated, these findings may give further insight into the biology of bladder carcinogenesis, allow testing of the RAD51 SNP as a potential predictive biomarker and also reveal potential targets for new cancer treatments.

Biomarkers for drug-induced renal damage and nephrotoxicity-an overview for applied toxicology

The detection of acute kidney injury (AKI) and the monitoring of chronic kidney disease (CKD) is becoming more important in industrialized countries. Because of the direct relation of kidney damage to the increasing age of the population, as well as the connection to other diseases like diabetes mellitus and congestive heart failure, renal diseases/failure has increased in the last decades. In addition, drug-induced kidney injury, especially of patients in intensive care units, is very often a cause of AKI. The need for diagnostic tools to identify drug-induced nephrotoxicity has been emphasized by the ICH-regulated agencies. This has lead to multiple national and international projects focusing on the identification of novel biomarkers to enhance drug development. Several parameters related to AKI or CKD are known and have been used for several decades. Most of these markers deliver information only when renal damage is well established, as is the case for serum creatinine. The field of molecular toxicology has spawned new options of the detection of nephrotoxicity. These new developments lead to the identification of urinary protein biomarkers, including Kim-1, clusterin, osteopontin or RPA-1, and other transcriptional biomarkers which enable the earlier detection of AKI and deliver further information about the area of nephron damage or the underlying mechanism. These biomarkers were mainly identified and qualified in rat but also for humans, several biomarkers have been described and now have to be validated. This review will give an overview of traditional and novel tools for the detection of renal damage.

TRAIL-mediated signaling in prostate, bladder and renal cancer

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is a death receptor ligand that has the ability to preferentially initiate apoptosis in malignant cells with minimal toxicity to normal cells. TRAIL-based therapeutics, including recombinant TRAIL, TRAIL-receptor agonistic antibodies and TRAIL gene therapy, have now entered clinical trials. Although these therapeutics are promising, concerns regarding TRAIL resistance are causing research efforts to shift towards the identification of effective combination therapies. Small-molecule inhibitors, natural compounds, and drugs approved for treatment of diseases other than cancer have been shown to affect TRAIL receptors, antiapoptotic proteins and survival pathways in prostate, bladder and renal cell lines and in preclinical models. Changes in endogenous TRAIL and TRAIL receptor expression during the development of genitourinary malignancies and the way in which the expression pattern is affected by treatment are of great interest, and understanding the biological consequences of such changes will be important to maximize the potential of TRAIL-based therapeutics.

MicroRNA in prostate, bladder, and kidney cancer: a systematic review

CONTEXT

MicroRNAs (miRNA) are noncoding RNAs that post-transcriptionally regulate gene expression. Their altered expression and function have been observed in most urologic cancers. MiRNAs represent potential disease biomarkers and novel therapeutic targets.

OBJECTIVE

To review and evaluate the evidence implicating miRNAs in the pathogenesis of prostate cancer (PCa), bladder cancer (BCa), and renal cancer.

EVIDENCE ACQUISITION

A systematic review was performed using PubMed and Embase to search for reports using strings for microRNA, non-coding RNA, cancer, prostate, bladder, and renal cancer. Identified manuscripts were retrieved and references searched. Selected studies were required to concentrate on the role of miRNA in these urologic cancers.

EVIDENCE SYNTHESIS

We reviewed articles that focus on this topic. More than 40 miRNAs have been implicated in urologic cancer and many target common carcinogenic pathways. In particular, apoptosis avoidance, cell proliferation, epithelial-to-mesenchymal transition, angiogenic signalling, and the generation of androgen independence are targeted or facilitated by more than one miRNA. Little work has been done to evaluate the translational applications for this knowledge to date. Novel therapeutic strategies have been developed and are under investigation to selectively modulate miRNAs; such work would potentially enable personalised tumour therapy.

CONCLUSIONS

MiRNAs appear to be important modulators of urologic cancer. Their expression is frequently altered in these tumours, and many are functionally implicated in their pathogenesis. They require evaluation to determine the translational role and therapeutic potential for this knowledge.

Epigenetic regulation of cell life and death decisions and deregulation in cancer

For every cell, there is a time to live and a time to die. It is apparent that cell life and death decisions are taken by individual cells based on their interpretation of physiological or non-physiological stimuli, or their own self-assessment of internal damage or changes in their environment. Apoptosis or programmed cell death is a key regulator of physiological growth control and regulation of tissue homoeostasis. One of the most important advances in cancer research in recent years is the recognition that cell death, mostly by apoptosis, is crucially involved in the regulation of tumour formation and also critically determines treatment response. The initiation and progression of cancer, traditionally seen as a genetic disease, is now realized to involve epigenetic abnormalities along with genetic alterations. The study of epigenetic mechanisms in cancer, such as DNA methylation, histone modifications and microRNA expression, has revealed a plethora of events that contribute to the neoplastic phenotype through stable changes in the expression of genes critical to cell death pathways. A better understanding of the epigenetic molecular events that regulate apoptosis, together with the reversible nature of epigenetic aberrations, should contribute to the emergence of the promising field of epigenetic therapy.

Diagnostic, prognostic and therapeutic implications of microRNAs in urologic tumors

MicroRNAs (miRNAs) are small, non-coding RNAs that have an important role in the regulation of carcinogenic pathways. The observations that miRNAs are differentially expressed in tumor versus corresponding normal tissue, and that they regulate important breakpoints during carcinogenesis, are of interest for urologic oncologists. As biomarkers, they might be helpful tools for diagnostic, prognostic and monitoring purposes. Furthermore, miRNAs might be potential targets for novel therapeutic strategies, especially in patients with tumor subtypes that do not respond to currently available therapies. In this Review, we will focus on the current proceedings of miRNA research in urologic tumors. In the past decade, the number of published articles related to miRNAs in urologic oncology has increased, highlighting the ongoing importance of miRNAs in this field. Current studies support the hypothesis that miRNA will gain influence in clinical practice. Here, therefore, we illustrate the current knowledge of miRNA function in urologic tumors and draw the attention of urologists to the future opportunities and challenges of this research field.