MicroRNA-145 directly targets the insulin-like growth factor receptor I in human bladder cancer cells

The role of miR-143/miR-145 in the development, diagnosis, and treatment of diabetes

Objectives

Diabetes mellitus [DM], is a multifaceted metabolic disease, which has become a worldwide threat to human wellness. Over the past decades, an enormous amount of attention has been devoted to understanding how microRNAs [miRNAs], a class of small non-coding RNA regulators of gene expression at the post-transcriptional level, are tied to DM pathology. It has been demonstrated that miRNAs control insulin synthesis, secretion, and activity. This review aims to provide an evaluation of the use of miR-143 and miR-145 as biomarkers for the diagnosis and prognosis of diabetes.

Methods

The use of miR-143 and miR-145 as biomarkers for the diagnosis and prognosis of diabetes has been studied, and research that examined this link was sought after in the literature. In addition, we will discuss the cellular and molecular pathways of insulin secretion regulation by miR-143/145 expression and finally their role in diabetes.

Results

In the current review, we emphasize recent findings on the miR-143/145 expression profiles as novel DM biomarkers in clinical studies and animal models and highlight recent discoveries on the complex regulatory effect and functional role of miR-143/145 expression in DM.

Conclusion

A novel clinical treatment that alters the expression and activity of miR-143/miR-145 may be able to return cells to their natural state of glucose homeostasis, demonstrating the value of using comprehensive miRNA profiles to predict the beginning of diabetes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01317-y.

Circular STAG2 RNA Modulates Bladder Cancer Progression via miR-145-5p/TAGLN2 and Is Considered as a Biomarker for Recurrence

The current study aimed to elucidate the regulatory mechanisms of the circRNA hsa_circ_0139697 (circSTAG2(16-25)) in BCa and to consider the opportunity of using circSTAG2(16-25) isolated from BCa patient urine as a marker for disease development prediction. The selection of this circRNA was determined by the special role of its parental gene STAG2 in BCa biology. The circRNA hsa_circ_0139697 was chosen from 25 STAG2 circRNAs due to its differential expression in the urine of BCa patients and healthy volunteers. Higher levels of circSTAG2(16-25) were detected in urine samples obtained from patients with recurrent tumors. A higher expression of circSTAG2(16-25) was also detected in more tumorigenic BCa cell lines. The overexpression of circSTAG2(16-25) in BCa cells induced the elevation of proliferation, motility, and invasion. To study the mechanisms of circSTAG2(16-25) activity, we confirmed that circSTAG2(16-25) can bind miR-145-5p in vitro as was predicted by bioinformatic search. miR-145-5p was shown to suppress some genes that promoted BCa progression. One of these genes, TAGLN2, encodes the protein Transgelin 2, which plays a role in BCa cell motility and invasion. Therefore, the possible mechanism of action of circSTAG2(16-25) could be sponging the tumor suppressor miR-145-5p, which results in activation of TAGLN2. In addition, circSTAG2(16-25) might be considered as a potential biomarker for recurrence prediction.

Targeting microRNA-145-mediated progressive phenotypes of early bladder cancer in a molecularly defined in vivo model

A progressive subclass of early-stage non-muscle-invasive bladder cancer (NMIBC) frequently recurs and progress into invasive carcinoma, thus decreasing the overall survival rate of NMIBC. However, therapeutic development for progressive NMIBC has been challenging due to the lack of molecularly validated in vivo models and agents targeting its genetic vulnerability. We herein molecularly characterized an interventional model of progressive NMIBC and revealed the principal functions and therapeutic potential of microRNA-145 (miR-145) in early bladder tumorigenesis. N-butyl-N-(4-hydroxybutyl)nitrosamine-induced premalignant lesions (BiPLs) in rats exhibited downregulated expression of miR-145 as well as highly similar mutation/expression profiles to those of the human progressive NMIBC subclass with the worst prognosis. The expression patterns of miR-145 inversely correlated with those of BC-related oncogenes in BiPLs. We also demonstrated that miR-145 dominantly regulated interferon pathways and c-Myc expression, which play a crucial role in the pathogenesis of progressive NMIBC. Furthermore, we demonstrated that miR-145 replacement with a novel miR-145-based intravesical agent (miR-145S1) significantly inhibited the progression of BiPLs in vivo. These results provide insights into the essential role of miR-145 as the earliest-acting oncogenic driver of bladder tumorigenesis as well as a validated interventional model and novel miR-145-based nucleic acid therapeutic agent for progressive NMIBC.

miRNAs role in bladder cancer pathogenesis and targeted therapy: Signaling pathways interplay - A review

Bladder cancer (BC) is the 11th most popular cancer in females and 4th in males. A lot of efforts have been exerted to improve BC patients' care. Besides, new approaches have been developed to enhance the efficiency of BC diagnosis, prognosis, therapeutics, and monitoring. MicroRNAs (miRNAs, miRs) are small chain nucleic acids that can regulate wide networks of cellular events. They can inhibit or degrade their target protein-encoding genes. The miRNAs are either downregulated or upregulated in BC due to epigenetic alterations or biogenesis machinery abnormalities. In BC, dysregulation of miRNAs is associated with cell cycle arrest, apoptosis, proliferation, metastasis, treatment resistance, and other activities. A variety of miRNAs have been related to tumor kind, stage, or patient survival. Besides, although new approaches for using miRNAs in the diagnosis, prognosis, and treatment of BC have been developed, it still needs further investigations. In the next words, we illustrate the recent advances in the role of miRNAs in BC aspects. They include the role of miRNAs in BC pathogenesis and therapy. Besides, the clinical applications of miRNAs in BC diagnosis, prognosis, and treatment are also discussed.

MicroRNAs as the critical regulators of protein kinases in prostate and bladder cancers

Background

Bladder cancer (BCa) and prostate cancer (PCa) are frequent urothelial and genital malignancies with a high ratio of morbidity and mortality which are more common among males. Since BCa and PCa cases are mainly diagnosed in advanced stages with clinical complications, it is required to introduce the efficient early detection markers. Protein kinases are critical factors involved in various cellular processes such as cell growth, motility, differentiation, and metabolism. Deregulation of protein kinases can be frequently observed through the neoplastic transformation and tumor progression. Therefore, kinases are required to be regulated via different genetic and epigenetic processes. MicroRNAs (miRNAs) are among the critical factors involved in epigenetic regulation of protein kinases. Since miRNAs are noninvasive and more stable factors in serum and tissues compared with mRNAs, they can be used as efficient diagnostic markers for the early detection of PCa and BCa.

Main body

In present review, we have summarized all of the reported miRNAs that have been associated with regulation of protein kinases in bladder and prostate cancers.

Conclusions

For the first time, this review highlights the miRNAs as critical factors in regulation of protein kinases during prostate and bladder cancers which paves the way of introducing a noninvasive kinase-specific panel of miRNAs for the early detection of these malignancies. It was observed that the class VIII receptors of tyrosine kinases and non-receptor tyrosine kinases were the most frequent targets for the miRNAs in bladder and prostate cancers, respectively.

CASC11 promotes aggressiveness of prostate cancer cells through miR-145/IGF1R axis

BACKGROUND

Prostate cancer (PCa) is the most common malignancy diagnosed among men after lung cancer in developed countries. Investigation of the underlying molecular mechanisms of PCa is urgently needed in order to develop better therapeutic strategies and to reveal more effective therapeutic targets. In this study, we aimed at exploring the potential functions of CASC11 in association with miR-145 and IGF1R during the malignant progression of PCa cells.

METHODS

We initially investigated the oncogenic potential of noncoding members of CASC gene family and analyzed the effects of CASC11 overexpression on proliferation, migration, and colony formation ability of DU145, LNCaP, and PC3 PCa cells. We, then, exprlored the association of CASC11, miR-145, and IGF1R expression and their impacts on PI3K/AKT/mTOR signaling pathway in in vitro models.

RESULTS

In silico analysis revealed that of the CASC family only CASC11 showed consistent results considering its differential expression as well as its association with the overall survival of patients. We demonstrated that ectopic overexpression of CASC11 significantly increased the proliferation, colony formation, and migration capacity in all three cell lines. CASC11 overexpression caused suppression of miR-145 and overexpression of IGF1R, leading to activation of PI3K/AKT/mTOR signaling pathway.

CONCLUSION

In summary, we found that CASC11 is upregulated in PCa cells and clinical tumor samples in comparison to corresponding controls and revealed that ectopic CASC11 overexpression promotes cellular phenotypes associated with PCa progression through CASC11/miR-145/IGF1R axis.

Propofol modulates the proliferation, invasion and migration of bladder cancer cells through the miR‑145‑5p/TOP2A axis

Propofol‑based anesthesia has been reported to reduce the recurrence and metastasis of a number of cancer types following surgical resection. However, the effects of propofol in bladder cancer (BC) are yet to be fully elucidated. The aim of the present study was to investigate the functions of propofol in BC and their underlying mechanisms. In the study, the expression of microRNA (miR)‑145‑5p in BC tissues and cell lines was evaluated using reverse transcription‑quantitative PCR, and the effects of propofol on BC cells were determined using cell viability, wound healing and Transwell cell invasion assays, bioinformatics analysis, western blotting, immunohistochemistry and in vivo tumor xenograft models. It was found that propofol significantly suppressed the proliferation, migration and invasion of BC cells in vitro. In addition, propofol induced miR‑145‑5p expression in a time‑dependent manner, and miR‑145‑5p knockdown attenuated the inhibitory effects of propofol on the proliferation, migration and invasion of BC cells. Topoisomerase II α (TOP2A) was a direct target of miR‑145‑5p, and silencing TOP2A reversed the effects of miR‑145‑5p knockdown in propofol‑treated cells. Furthermore, propofol suppressed tumor xenograft growth, which was partially attenuated by miR‑145‑5p knockdown. The present study provided novel insight into the advantages of surgical intervention with propofol anesthesia in patients with BC.

Genome-wide identification and functional prediction of circular RNAs in response to heat stress in Chinese Holstein cows

Heat stress (HS) leads to substantial economic loss of dairy industry each year. The negative effect of HS in dairy cows is becoming one of the more urgent issue due to accelerating side-effects of global warming. Various genes are involved in HS response but the information about the role of noncoding RNAs, especially circular RNAs (circRNAs) is largely unknown. In our study, we aimed to investigate the different expression profile of circRNAs between HS and Non-heat-stressed condition (NC) of Chinese Holstein cow's mammary gland. CircRNAs were identified using RNA sequencing and bioinformatics analysis. In total, 37405 circRNAs were detected and 95 were differentially expressed (DE), including 15 downregulated and 80 upregulated circRNAs in HS group compared to NC. Eight circRNAs were randomly selected to verify the RNA sequencing result. Further, Sanger sequencing validated the backsplicing site of the eight circRNAs. Moreover, results obtained from the Quantitative real time PCR (qRT-PCR) showed consistent expression trend with that of RNA sequencing. GO annotation and KEGG analysis suggested that these DE circRNAs probably involved in the energy metabolic regulation. Furthermore, we constructed ceRNA network and the result indicated that these DE circRNAs could regulate lactation through IGF1 and PRL signaling pathway.

MicroRNAs and target molecules in bladder cancer

Bladder cancer (BC) is considered as one of the most common malignant tumors in humans with complex pathogenesis including gene expression variation, protein degradation, and changes in signaling pathways. Many studies on involved miRNAs in BC have demonstrated that they could be used as potential biomarkers in the prognosis, response to treatment, and screening before the cancerous phenotype onset. MicroRNAs (miRNAs) regulate many cellular processes through their different effects on special targets along with modifying signaling pathways, apoptosis, cell growth, and differentiation. The diverse expression of miRNAs in cancerous tissues could mediate procedures leading to the oncogenic or suppressor behavior of certain genes in cancer cells. Since a specific miRNA may have multiple targets, an mRNA could also be regulated by multiple miRNAs which further demonstrates the actual role of miRNAs in cancer. In addition, miRNAs can be utilized as biomarkers in some cancers that cannot be screened in the early stages. Hence, finding blood, urine, or tissue miRNA biomarkers by novel or routine gene expression method could be an essential step in the prognosis and control of cancer. In the present review, we have thoroughly evaluated the recent findings on different miRNAs in BC which can provide comprehensive information on better understanding the role of diverse miRNAs and better decision making regarding the new approaches in the diagnosis, prognosis, prevention, and treatment of BC.

MicroRNAs: potential biomarkers for diagnosis and prognosis of different cancers

A thorough understanding of the tumor environment and underlying genetic factors helps in the better formulation of cancer management strategies. Availability of efficient diagnostic and prognostic biomarkers facilitates early detection and progression of the disease. MicroRNAs affect different biological processes participating in tumorigenesis through regulation of their target genes. An expanding list of unique RNAs and understanding of their regulatory role has opened up a new field in cancer research. Based on a comprehensive literature search, we identified 728 miRNAs dysregulated in sixteen cancer types namely bladder cancer (BC), breast cancer (BrC), cervical cancer (CC), colorectal cancer (CRC), esophageal cancer (EC), endometrial cancer (EnC), gastric cancer (GC), hepatocellular cancer (HCC), head and neck squamous cell cancer (HNSCC), lung cancer (LC), ovarian cancer (OC), pancreatic cancer (PC), prostate cancer (PrC), renal cell cancer (RCC), skin cancer (SC), and thyroid cancer (TC). Expression of 43 miRNAs was either upregulated or downregulated in six or more of these cancers. Finally, seven miRNAs namely mir-18a, mir-21, mir-143/145, mir-210, mir-218, mir-221, showing maximum dysregulation, either up- or down-regulation in the majority of cancers, were selected for a detailed presentation of their expression and evaluation of their potential as biomarkers in the diagnosis and prognosis of different cancers.

Regulation of IRS-1, insulin signaling and glucose uptake by miR-143/145 in vascular smooth muscle cells

Regulation of insulin signaling by microRNAs in smooth muscle cells may contribute to diabetic vascular disease. The two smooth muscle enriched miRNAs miR-143 and miR-145 have been reported to target mediators of insulin signaling in non-smooth muscle cells. In this study, we aimed to determine the importance of this regulation in vascular smooth muscle cells, where expression of miR-143/145 is much higher than in other cell types. Smooth muscle cells deficient of the miR-143/145 cluster were used, as well as smooth muscle cells transfected with mimics/inhibitors for either miR-143 or miR-145. We found that deletion of miR-143/145 in smooth muscle results in a dramatic upregulation IRS-1 expression and insulin signaling, and an increased insulin-induced glucose uptake. Furthermore, specific modulation of either miR-145 or miR-143 expression regulated specific targets (IRS-1, ORP8 and the IGF-1 receptor) in the insulin signaling pathway. Consequently, transient inhibition or overexpression of either miR-143 or miR-145 was sufficient to regulate insulin signaling in smooth muscle cells. In conclusion, the results of this study support an important role for both miR-143 and miR-145 in the regulation of insulin signaling and glucose uptake in vascular smooth muscle cells.

LINC00958 Involves in Bladder Cancer Through Sponging miR-378a-3p to Elevate IGF1R

Background: LINC00958 is involved in bladder cancer, but its mechanism of action remains indistinct. This study further analyzed its potential targets, aiming to search for therapeutic targets. Materials and Methods: miR-378a-3p was predicted to bind to LINC00958 and IGF1R, which was verified by double-luciferase reporter analysis. The levels of LINC00958 and miR-378a-3p in bladder cancer tissues and cells, and their correlation were further analyzed. Then LINC00958, miR-378a-3p, and IGF1R in bladder cancer cells were up- or downregulated, and their effects on cell viability, migration, and invasion of cells were detected, respectively. Results: LINC00958 binds to miR-378a-3p whose target gene was IGF1R. The expression of miR-378a-3p was negative relative with the level of LINC00958 and IGF1R. Overexpressed miR-378a-3p restrained the activity, migration, and invasion of bladder cancer cells, which was the same as the effects of silent LINC00958 and downregulated IGF1R. Nonetheless, upregulated LINC00958 rescued the antitumor effect of overexpressed miR-378a-3p, whereas miR-378a-3p inhibitor acted as a cancer promoter to reverse the inhibition of downregulated IGF1R on cell activity, migration, and invasion. Conclusion: LINC00958 accelerated the propagation and metastasis of bladder cancer cells through sponging miR-378a-3p to elevate IGF1R, which might trigger a new direction for the treatment of bladder cancer.

Comprehensive circular RNA profiling reveals the regulatory role of circ_100242/miR-145 pathway in bladder cancer

Bladder cancer is a common genitourinary carcinoma with high morbidity and mortality rates. Circular RNAs (circRNAs), which are a type of single-stranded RNAs, have been characterized as stable, conserved and tissue-specific molecules in mammalian cells. The present study explored the circRNA expression profile in four bladder cancer tissues and matched normal samples by using microarray analysis. Furthermore, bioinformatics analyses were performed to investigate the potential function of dysregulated circRNAs in bladder cancer. The results demonstrated that 89 circRNAs were downregulated and 210 circRNAs were upregulated in bladder cancer tissues. The results from RT-qPCR demonstrated that hsa_circ_100241, hsa_circ_100242 and hsa_circ_101303 were markedly upregulated whereas hsa_circ_104510 was significantly downregulated in bladder cancer tissues compared with normal tissue. Following circRNA/microRNA (miRNA) interaction network generation via Cytoscape, it was demonstrated that hsa_circ_100242 contained a miRNA response element for miR-145-5p, which is a tumor suppressor in bladder carcinoma. In addition, results from the Kyoto Encyclopedia of Genes and Genomes analysis showed that the MAPK signaling pathway was the most significant pathway of the differentially expressed circRNAs in bladder cancer tissues. In conclusion, the present study demonstrated that circRNAs were dysregulated in bladder cancer tissues compared with matched normal samples. Pathway analysis was also performed to predict the binding of miRNAs to the dysregulated circRNAs. The results revealed that hsa_circ_100242 may be involved in bladder cancer initiation and progression by sponging miR-145. These findings may provide further insights into the functional and therapeutic roles of circRNAs in bladder cancer.

Celecoxib inhibits the epithelial-to-mesenchymal transition in bladder cancer via the miRNA-145/TGFBR2/Smad3 axis

Celecoxib, a selective cyclooxygenase-2 inhibitor, has chemo-preventive activity against different cancer types, including bladder cancer (BC). However, the mechanisms by which celecoxib exerts its cancer preventative effects have yet to be completely understood. In the present study, the effect of celecoxib on the epithelial-to-mesenchymal transition (EMT) of BC cells and its potential molecular mechanisms were investigated. The results of the present study demonstrated that celecoxib inhibited the proliferation, migration, invasion and EMT of BC cells. Further investigation of the underlying mechanism revealed that celecoxib inhibited EMT by upregulating microRNA (miR)-145 and downregulating the expression of transforming growth factor β receptor 2 and SMAD family member 3. Furthermore, the combination of celecoxib with miR-145 mimics demonstrated an additive migration and invasion-inhibitory effect in BC cell lines.

miR‑145 suppresses ovarian cancer progression via modulation of cell growth and invasion by targeting CCND2 and E2F3

MicroRNAs (miRNA/miRs) have been demonstrated to be critical post‑transcriptional modulators of gene expression during tumorigenesis. Numerous miRNAs have been revealed to be downregulated in human epithelial ovarian cancer (EOC). In the present study, it was observed that the expression of miR‑145 was decreased in EOC tissues and cell lines. Overexpression of miR‑145 inhibited the proliferation, migration and invasion of EOC cells. The D‑type cyclin 2, cyclin D2 (CCND2), and E2F transcription factor 3 (E2F3) were confirmed to be targets of miR‑145. In addition, restoration of these 2 genes significantly reversed the tumor suppressive effects of miR‑145. Collectively, the results indicated that miR‑145 serves a critical role in suppressing the biological behavior of EOC cells by targeting CCND2 and E2F3. Therefore, miR‑145 was suggested to be a potential miRNA‑based therapeutic target in ovarian cancer.

Function of microRNA-145 and mechanisms underlying its role in malignant tumor diagnosis and treatment

miRNAs are single-stranded small RNAs that do not encode proteins. They can combine complementarily with the 3′-UTRs of target gene mRNA molecules to promote targeted mRNA degradation or inhibit mRNA translation, thereby regulating gene expression at the post-transcriptional level. MiRNAs participate in regulation of cell cycling, growth, apoptosis, differentiation, and stress responses. MiRNA-145 (miR-145) is a tumor suppressor that targets various tumor-specific genes and proteins, thereby influencing related signaling pathways. MiR-145 not only regulates tumor growth, invasion, and metastasis, but is also important for tumor angiogenesis and tumor stem cell proliferation. Here, we review the roles and mechanisms of miR-145 in the diagnosis and treatment of malignant tumors. Published data confirm that miR-145 expression in various tumors is significantly lower than that in normal tissues and that overexpression of miR-145 inhibits the growth of different tumor cells, significantly reduces the ability of tumors to spread, and improves sensitivity to chemotherapeutic drugs. We conclude that miR-145 is a potential marker for use in the early diagnosis and prognostic evaluation of patients with cancer, has a role as a tumor suppressor, and is a promising cancer treatment target candidate.

MicroRNA-31 functions as a tumor suppressor and increases sensitivity to mitomycin-C in urothelial bladder cancer by targeting integrin α5

Urothelial bladder cancer (UBC) is a common genitourinary malignancy. MiR-31, a well-identified miRNA, exhibits diverse properties in different cancers. However, the specific functions and mechanisms of miR-31 in UBC have not been investigated. In this study, tumor samples, especially invasive UBC, showed significantly reduced level of miR-31, as compared with normal urothelium. Prognostic analysis using the EORTC model showed that down-regulation of miR-31 correlated with higher risks of recurrence and progression in noninvasive UBC cases. Remarkably, overexpression of miR-31 mimics in UBC cell lines inhibited cell proliferation, migration and invasion. Integrin α5 (ITGA5), an integrin family member, was subsequently identified as a direct target of miR-31 in UBC cells. When treated with mitomycin-C (MMC), miR-31-expressing UBC cells displayed lower survival and higher apoptotic rates, and deactivated Akt and ERK. These effects arising from miR-31 overexpression were abrogated by ITGA5 restoration. Furthermore, miR-31 markedly inhibited tumor growth and increased the effectiveness of MMC in UBC xenografts. In summary, our data suggest that miR-31 is a prognostic predictor and can serve as a potential therapeutic target of UBC.

Role of downregulated miR-133a-3p expression in bladder cancer: a bioinformatics study

It has been discovered that miR-133a-3p acts as a tumor suppressor in bladder cancer (BC). Nevertheless, the function of miR-133a-3p in BC remains unclarified. Thus, we carried out this study to validate the expression of miR-133a-3p in BC and provide insights into the molecular mechanism underlying it. To assess the expression of miR-133a-3p in BC, we searched eligible studies from literature and Gene expression Omnibus (GEO) to perform a meta-analysis. We also plotted the summary receiver operating characteristic (SROC) curve to evaluate the diagnostic ability of miR-133a-3p in BC. Additionally, the potential target genes of miR-133a-3p were acquired from 14 online software programs and GEO database. Protein-protein interaction (PPI) network was created to identify the hub genes. Then, Gene Ontology (GO) functional annotation analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were carried out to investigate the regulatory network of the target genes. From the meta-analysis, miR-133a-3p was remarkably downregulated in BC tissues compared with that in non-cancer tissues (standard mean difference =−3.84, 95% confidence interval =−6.99–0.29). Moreover, results from SROC suggested that miR-133a-3p exhibited the ability to diagnose BC (area under curve =0.8418). As for the bioinformatics study, 488 genes were chosen as the potential targets of miR-133a-3p in BC, among which 10 genes were defined as hub genes (all degrees >5). Further GO and KEGG pathway analysis indicated that the target genes of miR-133a-3p aggregated in specific biological process and pathways. In conclusion, miR-133a-3p possessed great diagnostic potential with its downregulation in BC, and miR-133a-3p might serve as a novel biomarker for BC.

Understanding the Role of Non-Coding RNAs in Bladder Cancer: From Dark Matter to Valuable Therapeutic Targets

The mortality and morbidity that characterize bladder cancer compel this malignancy into the category of hot topics in terms of biomolecular research. Therefore, a better knowledge of the specific molecular mechanisms that underlie the development and progression of bladder cancer is demanded. Tumor heterogeneity among patients with similar diagnosis, as well as intratumor heterogeneity, generates difficulties in terms of targeted therapy. Furthermore, late diagnosis represents an ongoing issue, significantly reducing the response to therapy and, inevitably, the overall survival. The role of non-coding RNAs in bladder cancer emerged in the last decade, revealing that microRNAs (miRNAs) may act as tumor suppressor genes, respectively oncogenes, but also as biomarkers for early diagnosis. Regarding other types of non-coding RNAs, especially long non-coding RNAs (lncRNAs) which are extensively reviewed in this article, their exact roles in tumorigenesis are—for the time being—not as evident as in the case of miRNAs, but, still, clearly suggested. Therefore, this review covers the non-coding RNA expression profile of bladder cancer patients and their validated target genes in bladder cancer cell lines, with repercussions on processes such as proliferation, invasiveness, apoptosis, cell cycle arrest, and other molecular pathways which are specific for the malignant transformation of cells.

Demethylation of the MIR145 promoter suppresses migration and invasion in breast cancer

miR-145 has been implicated in the progression of breast cancer. Here, we report that its expression is decreased in breast cancer specimens and cell lines and that this low level of expression is associated with DNA methylation of its gene, MIR145. Methylation of MIR145 has previously been correlated with cell migration and invasion, both in vivo and in vitro. We found that demethylation of MIR145 reactivates miR-145 and contributes to the anti-cancer properties of 5-aza-2'-deoxyazacytidine (5-AzaC). Therefore, miR-145 is a potentially valuable biomarker for breast cancer.

miR-143 inhibits bladder cancer cell proliferation and enhances their sensitivity to gemcitabine by repressing IGF-1R signaling

microRNAs (miRNAs) are a class of small RNAs that regulate gene expression. It has been demonstrated that aberrant miRNA expression is associated with cancer development and carcinogenesis. Altered miRNA expression has been suggested to occur in bladder cancer. In other cancer systems, studies have indicated that miR-143, as a tumor suppressor gene, plays essential roles in cancer progression. However, its role in bladder cancer has yet to be elucidated. In the present study, we observed that miR-143 expression was downregulated in human bladder cancer tissues and cells, and that its levels were negatively correlated with bladder cancer clinical stages. We further demonstrated that insulin-like growth factor-1 receptor (IGF-1R) is a functional target of miR-143. Their expression levels were inversely correlated in bladder cancer samples. Overexpression of miR-143 inhibited cell proliferation and promoted chemosensitivity of bladder cancer 5637 cells to gemcitabine. Consistently, small interfering RNA-mediated knockdown of IGF-1R phenocopied miR-143 overexpression. Notably, the expression of IGF-1R is a predictor of patient prognosis. Collectively, our findings indicate that miR-143 is a valuable biomarker for bladder cancer. The miR-143/IGF-1R axis is associated with bladder cancer drug resistance and patient survival.

MiRNA-145 increases therapeutic sensibility to gemcitabine treatment of pancreatic adenocarcinoma cells

Pancreatic adenocarcinoma is one of the most leading causes of cancer-related deaths worldwide. Although recent advances provide various treatment options, pancreatic adenocarcinoma has poor prognosis due to its late diagnosis and ineffective therapeutic multimodality. Gemcitabine is the effective first-line drug in pancreatic adenocarcinoma treatment. However, gemcitabine chemoresistance of pancreatic adenocarcinoma cells has been a major obstacle for limiting its treatment effect. Our study found that p70S6K1 plays an important role in gemcitabine chemoresistence. MiR-145 is a tumor suppressor which directly targets p70S6K1 for inhibiting its expression in pancreatic adenocarcinoma, providing new therapeutic scheme. Our findings revealed a new mechanism underlying gemcitabine chemoresistance in pancreatic adenocarcinoma cells.

MiR-145 functions as a tumor suppressor via regulating angiopoietin-2 in pancreatic cancer cells

Background

Pancreatic cancer is currently one of the leading causes of cancer deaths without any effective therapies. Mir-145 has been found to be tumor-suppressive in various types of cancers. The aim of this study is to investigate the role of miR-145 in pancreatic cancer cells and explore its underlying mechanism.

Methods

Quantitative real time PCR was used to determine the expression level of miR-145 and angiopoietin-2 (Ang-2) mNRA, and the expression level of Ang-2 protein was measured by western blotting. The anti-cancer activities of miR-145 were tested both in in vitro by using cell invasion and colony formation assay and in vivo by using xenograft assay. The direct action of miR-145 on Ang-2 was predicted by TargetScan and confirmed by luciferase report assay. The vascularization of xenografts were performed by immunohistochemical analysis.

Results

The expression level of miR-145 was significantly lower and the expression levels of Ang-2 mRNA and protein was significantly higher in the more aggressive pancreatic cancer cells (MiaPaCa-2 and Panc-1) when compared to that in BxPC3 cells. Overexpression of miR-145 in the BxPC3, MiaPaCa-2 and Panc-1 cells suppressed the cell invasion and colony formation ability, and the expression level of Ang-2 protein in MiaPaCa-2 and Panc-1 cells was also suppressed after pre-miR-145 transfection. Intratumoral delivery of miR-145 inhibited the growth of pancreatic cancer xenografts and angiogenesis in vivo, and also suppressed the expression level of angiopoietin-2 protein. Luciferase report assay showed that Ang-2 is a direct target of miR-145, and down-regulation of angiopoietin-2 by treatment with Ang-2 siRNA in the BxPC3, MiaPaCa-2 and Panc-1 cells suppressed cell invasion and colony formation ability. The reverse transcription PCR results also showed that Tie1 and Tie2 were expressed in BxPC3, MiaPaCa-2 and Panc-1 cells.

Conclusion

MiR-145 functions as a tumor suppressor in pancreatic cancer cells by targeting Ang-2 for translation repression and thus suppresses pancreatic cancer cell invasion and growth, which suggests that restoring of miR-145 may be a potential therapeutic target for pancreatic cancer.

A Functional rs353293 Polymorphism in the Promoter of miR-143/145 Is Associated with a Reduced Risk of Bladder Cancer

BACKGROUND AND OBJECTIVES

MicroRNA (miR)-143/145, known as tumor suppressors, can promote cell apoptosis and differentiation, and suppress cell proliferation, invasion and migration. We performed a case-control study to investigate the association of rs353293 in the promoter region of miR-143/145 with bladder cancer risk.

METHODS

In total, 869 subjects including 333 cases and 536 controls were enrolled in this study, and the rs353293 polymorphism was genotyped by using a Taqman assay. The promoter activity was measured by the Dual-Luciferase Assay System.

RESULTS

We calculated an adjusted odds ratio of 0.64 for the presence of either AA/AG genotypes (95% CI 0.46-0.90) and 0.64 (95% CI 0.47-0.87) for carrying at least one A allele in bladder cancer. Stratified analyses showed that the AA/AG genotypes and the A allele were less prevalent in patients with low grade tumors, compared to those harboring higher grade bladder cancers (adjusted OR = 0.53, 95% CI, 0.30-0.94, P = 0.03 and adjusted OR = 0.54, 95% CI, 0.32-0.92, P = 0.02, respectively). In vitro luciferase reporter analysis showed that rs353293A allele had a lower activity compared with the rs353293G allele (P < 0.001).

CONCLUSION

These findings suggest that the functional rs353293 polymorphism may be a useful biomarker to predict the risk of bladder cancer.

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.

MicroRNA‑335 inhibits bladder cancer cell growth and migration by targeting mitogen‑activated protein kinase 1

The abnormal expression of microRNAs (miRs) as oncogenes or tumor‑suppressor genes has been widely investigated in various tumor types. However, the roles of miR‑335 in bladder cancer cells have remained elusive. The aim of the present study was to assess the expression of miR‑335 in bladder cancer as well as the effects of miR‑335 on bladder cancer cell proliferation, metastasis and apoptosis. PCR and western blot analyses revealed that miR‑335 was significantly downregulated in bladder cancer tissues, and low levels of miR‑335 were associated with more aggressive phenotypes of bladder cancer. Overexpression of miR‑335 in T24 cells inhibited cell proliferation and induced apoptosis as indicated by an MTT assay and flow cytometric analysis, respectively. Furthermore, overexpression of miR‑335 significantly suppressed cell migration, as indicated by a Transwell assay. The expression of mitogen‑activated protein kinase (MAPK)1 was decreased after overexpression of miR‑335, indicating that MAPK1 may be a target gene of miR‑335. In addition, silencing of MAPK1 inhibited the proliferation and migration of bladder cancer cells. In conclusion, the results of the present study demonstrated that miR‑335 was significantly downregulated in bladder cancer, and may act as a tumor suppressor through repression of MAPK1.

The role of microRNAs in bladder cancer

Bladder cancer (BC) is the fifth most common cancer worldwide and is associated with significant morbidity and mortality. The prognosis of muscle invasive BC is poor, and recurrence is common after radical surgery or chemotherapy. Therefore, new diagnostic methods and treatment modalities are critical. MicroRNAs (miRNAs), a class of small noncoding RNAs, regulate the expression of protein-coding genes by repressing translation or cleaving RNA transcripts in a sequence-specific manner. miRNAs have important roles in the regulation of genes involved in cancer development, progression, and metastasis. The availability of genomewide miRNA expression profiles by deep sequencing technology has facilitated rapid and precise identification of aberrant miRNA expression in BC. Indeed, several miRNAs that are either upregulated or downregulated have been shown to have associations with significant cancer pathways. Furthermore, many miRNAs, including those that can be detected in urine and blood, have been studied as potential noninvasive tumor markers for diagnostic and prognostic purposes. Here, we searched PubMed for publications describing the role of miRNAs in BC by using the keywords "bladder cancer" and "microRNA" on March 1, 2016. We found 374 papers and selected articles written in English in which the level of scientific detail and reporting were sufficient and in which novel findings were demonstrated. In this review, we summarize these studies from the point of view of miRNA-related molecular networks (specific miRNAs and their targets) and miRNAs as tumor markers in BC. We also discuss future directions of miRNA studies in the context of therapeutic modalities.

Optimization of a cationic liposome-based gene delivery system for the application of miR-145 in anticancer therapeutics

In order to improve the delivery efficiency of microRNA (miRNA or miR)-145, the present study examined several factors which may affect cationic liposome (CL)-based transfection, including the hydration medium used for the preparation of liposomes, the quantity of the plasmid, the molar ratio of N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP)/cholesterol (chol), or DOTAP/chol, and the weight ratio of DOTAP/DNA. In order to enhance the transfection efficiency, protamine was selected as a DNA-condensing agent to form liposome‑protamine‑DNA (LPD) ternary complexes. An agarose gel retardation assay was used to examine the DNA binding affinity of the CLs. Following transfection, GFP fluorescence images were captured and flow cytometry was performed to determine the transfection efficiency. Furthermore, an MTT assay was performed to determine the cytotoxicity of the liposome complexes. The final optimal conditions were as follows: 5% glucose as the hydration medium, a molar ratio of DOTAP/chol at 3:1 for the preparation of CLs, a weight ratio of DOTAP/protamine/DNA of 3:0.5:1, with 8 µg plasmid added for the preparation of the LPD complexes. In vitro, the LPD complexes exhibited an enhanced transfection efficiency and low cytotoxicity, which indicated that the presented LPD vector enhanced the transfection efficiency of the CLs. The HepG2 cells were found to have the lowest expression levels of miR‑145 out of the cell lines tested (A549, BGC-823, HepG2, HeLa, LoVo and MCF-7). Following the transient transfection of the HepG2 cells with miR‑145, the results revealed that the overexpression of miR‑145 inhibited the proliferation of the HepG2 cells and downregulated the expression of cyclin-dependent kinase 6 (CDK6), cyclinD1, c-myc, and Sp1 transcription factor (Sp1). In conclusion, in this study, we optimized a liposome‑based delivery system for the efficient delivery of miR‑145 into cancer cells. This may provide a foundation for further research into the use of miR‑145 in anticancer therapeutics.

Chloroquine enhances the efficacy of cisplatin by suppressing autophagy in human adrenocortical carcinoma treatment

BACKGROUND

It has been demonstrated that chloroquine (CQ) enhances the efficacy of chemotherapy. However, little is known about whether CQ could enhance the efficacy of cisplatin (DDP) in the treatment of adrenocortical carcinoma (ACC). In this study, we explore the efficacy and mechanism by which CQ affects DDP sensitivity in human ACC in vitro and in vivo.

METHODS

The autophagic gene Beclin-1 expression was detected by immunohistochemistry, and the protein levels were analyzed using immunoblotting assays of ACC tissues and normal adrenal cortex tissues. The ACC SW13 cells were treated with DDP and/or CQ. The cell viability assay was performed using the MTT method. Qualitative autophagy detection was performed by monodansylcadaverine staining of autophagic vacuoles. Annexin V-fluorescein isothiocyanate/propidium iodide double staining was used to count cell apoptosis by flow cytometry. The autophagy-related protein (Beclin-1, LC3, and p62) and apoptosis relative protein (Bax and Bcl-2) levels were evaluated with Western blot analysis. Furthermore, a murine model of nude BALB/c mice bearing SW13 cell xenografts was established to evaluate the efficacy of concomitant therapy.

RESULTS

The expression of the autophagic gene Beclin-1 was significantly downregulated in ACC tissues compared to normal adrenal cortex tissues. The Beclin-1 protein level in ACC tissues was lower than that in normal adrenal cortex tissues (P<0.05). In vitro concomitant therapy (DDP and CQ) was more effective in restraining SW13 cell proliferation. DDP could promote cell apoptosis and induce autophagy in SW13 cells. Concomitant therapy further promoted cell apoptosis by inhibiting autophagy. In vivo, we found that concomitant therapy was more potent than DDP monotherapy in inhibiting the growth of xenografted tumors and prolonging the survival of tumor-bearing mice.

CONCLUSION

The antitumor ability of DDP was related to autophagy activity, and the concomitant therapy (DDP and CQ) could be an optimal strategy for treating ACC.

Cisplatin and Paclitaxel Alter the Expression Pattern of miR-143/145 and miR-183/96/182 Clusters in T24 Bladder Cancer Cells

Although cisplatin-based chemotherapy is considered to be the treatment of choice for metastatic bladder cancer, its efficacy and tolerability has proven to be limited. MicroRNAs are small noncoding RNAs, whose genes are frequently organized in clusters. These molecules constitute posttranscriptional regulators of mRNA expression and are claimed to be deregulated in cancer. miR-143/145 and miR-183/96/182 clusters have been extensively studied in bladder cancer cells. Herein, we tried to add up to this knowledge by assessing the expression levels of the five mature microRNAs derived from the aforementioned clusters in T24 bladder cancer cells exposed to either cisplatin or paclitaxel. For both compounds, the viability of treated T24 cells was estimated via the MTT colorimetric assay and the Trypan Blue exclusion method, while a fraction of the cells was left to recover. The expression levels of all mature microRNAs were finally quantified both in treated and in recovered cells by performing real-time PCR. According to our data, cisplatin and paclitaxel strongly decreased T24 cells' viability, showing in parallel the ability to significantly down-regulate miR-143 levels, and up-regulate the expression levels of miR-145, miR-183, miR-96, and miR-182, which, in their total, demonstrated case-specific variations after recovery period.

Identification of a hypoxia-regulated miRNA signature in bladder cancer and a role for miR-145 in hypoxia-dependent apoptosis

BACKGROUND

Hypoxia leads to the stabilisation of the hypoxia-inducible factor (HIF) transcription factor that drives the expression of target genes including microRNAs (miRNAs). MicroRNAs are known to regulate many genes involved in tumourigenesis. The aim of this study was to identify hypoxia-regulated miRNAs (HRMs) in bladder cancer and investigate their functional significance.

METHODS

Bladder cancer cell lines were exposed to normoxic and hypoxic conditions and interrogated for the expression of 384 miRNAs by qPCR. Functional studies were carried out using siRNA-mediated gene knockdown and chromatin immunoprecipitations. Apoptosis was quantified by annexin V staining and flow cytometry.

RESULTS

The HRM signature for NMI bladder cancer lines includes miR-210, miR-193b, miR-145, miR-125-3p, miR-708 and miR-517a. The most hypoxia-upregulated miRNA was miR-145. The miR-145 was a direct target of HIF-1α and two hypoxia response elements were identified within the promoter region of the gene. Finally, the hypoxic upregulation of miR-145 contributed to increased apoptosis in RT4 cells.

CONCLUSIONS

We have demonstrated the hypoxic regulation of a number of miRNAs in bladder cancer. We have shown that miR-145 is a novel, robust and direct HIF target gene that in turn leads to increased cell death in NMI bladder cancer cell lines.

MicroRNA-145 targets MUC13 and suppresses growth and invasion of pancreatic cancer

Pancreatic cancer has a poor prognosis due to late diagnosis and ineffective therapeutic multimodality. MUC13, a transmembrane mucin is highly involved in pancreatic cancer progression. Thus, understanding its regulatory molecular mechanisms may offer new avenue of therapy for prevention/treatment of pancreatic cancer. Herein, we report a novel microRNA (miR-145)-mediated mechanism regulating aberrant MUC13 expression in pancreatic cancer. We report that miR-145 expression inversely correlates with MUC13 expression in pancreatic cancer cells and human tumor tissues. miR-145 is predominantly present in normal pancreatic tissues and early Pancreatic Ductal Adenocarcinoma (PDAC) precursor lesions (PanIN I) and is progressively suppressed over the course of development from PanIN II/III to late stage poorly differentiated PDAC. We demonstrate that miR-145 targets 3′ untranslated region of MUC13 and thus downregulates MUC13 protein expression in cells. Interestingly, transfection of miR-145 inhibits cell proliferation, invasion and enhances gemcitabine sensitivity. It causes reduction of HER2, P-AKT, PAK1 and an increase in p53. Similar results were found when MUC13 was specifically inhibited by shRNA directed at MUC13. Additionally, intratumoral injections of miR-145 in xenograft mice inhibited tumor growth via suppression of MUC13 and its downstream target, HER2. These results suggest miR-145 as a novel regulator of MUC13 in pancreatic cancer.

Regulation of microRNA during cardiomyocyte maturation in sheep

Background

There is a limited capacity to repair damage in the mammalian heart after birth, which is primarily due to the inability of cardiomyocytes to proliferate after birth. This is in contrast to zebrafish and salamander, in which cardiomyocytes retain the ability to proliferate throughout life and can regenerate their heart after significant damage. Recent studies in zebrafish and rodents implicate microRNA (miRNA) in the regulation of genes responsible for cardiac cell cycle progression and regeneration, in particular, miR-133a, the miR-15 family, miR-199a and miR-590. However, the significance of these miRNA and miRNA in general in the regulation of cardiomyocyte proliferation in large mammals, including humans, where the timing of heart development relative to birth is very different than in rodents, is unclear. To determine the involvement of miRNA in the down-regulation of cardiomyocyte proliferation occurring before birth in large mammals, we investigated miRNA and target gene expression in sheep hearts before and after birth. The experimental approach included targeted transcriptional profiling of miRNA and target mRNA previously identified in rodent studies as well as genome-wide miRNA profiling using microarrays.

Results

The cardiac expression of miR-133a increased and its target gene IGF1R decreased with increasing age, reaching their respective maximum and minimum abundance when the majority of ovine cardiomyocytes were quiescent. The expression of the miR-15 family members was variable with age, however, four of their target genes decreased with age. These latter profiles are inconsistent with the direct involvement of this family of miRNA in cardiomyocyte quiescence in late gestation sheep. The expression patterns of ‘pro-proliferative’ miR-199a and miR-590 were also inconsistent with their involvement in cardiomyocyte quiescence. Consequently, miRNA microarray analysis was undertaken, which identified six discrete clusters of miRNA with characteristic developmental profiles. The functions of predicted target genes for the miRNA in four of the six clusters were enriched for aspects of cell division and regulation of cell proliferation suggesting a potential role of these miRNA in regulating cardiomyocyte proliferation.

Conclusion

The results of this study show that the expression of miR-133a and one of its target genes is consistent with it being involved in the suppression of cardiomyocyte proliferation, which occurs across the last third of gestation in sheep. The expression patterns of the miR-15 family, miR-199a and miR-590 were inconsistent with direct involvement in the regulation cardiomyocyte proliferation in sheep, despite studies in rodents demonstrating that their manipulation can influence the degree of cardiomyocyte proliferation. miRNA microarray analysis suggests a coordinated and potentially more complex role of multiple miRNA in the regulation of cardiomyocyte quiescence and highlights significant differences between species that may reflect their substantial differences in the timing of this developmental process.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1693-z) contains supplementary material, which is available to authorized users.

A prostate cancer-targeted polyarginine-disulfide linked PEI nanocarrier for delivery of microRNA

Recent advances in efficient microRNA (miRNA) delivery techniques using prostate cancer-targeted nanoparticles offer critical information for understanding the functional role of miRNAs in vivo, and for supporting targeted gene therapy in terms of treating miRNA-associated prostate cancer. Here, we report the polyarginine peptide (R11)-labeled non-toxic SSPEI nanomaterials capable of prostate cancer-specific miR-145 delivery to prostate cancer in vivo where they display full bioactivity at completely nontoxic concentrations. The R11-labeled BPEI-SS (R11-SSPEI) nanocarrier showed less toxicity in prostate cancer, and electrostatic interaction of R11-SSPEI with miR-145 exhibited optimal transfection efficacy. The R11-SSPEI/miR-145 polymer could be specifically uptaken in prostate cancer using FAM-miR-145 mixed with R11-SSPEI. The functional action of miR-145 oligomers released from polyplexes was evaluated by a reporter vector containing a miR-145-binding sequence, and showed a significantly reduced reporter signal in a dose-dependent manner. More importantly, in a peritoneal mouse tumor model, the systemic administration of the R11-SSPEI/FAM-miR-145 complex leads to the delivery of miR-145 into the tumors, dramatically inhibiting tumor growth and prolonged survival time. Hence, we establish a novel and prostate cancer-specific targeting system for the systemic in vivo application of microRNAs through R11-SSPEI complexation as a powerful tool for future therapeutic use.

A panel of eight-miRNA signature as a potential biomarker for predicting survival in bladder cancer

BACKGROUND

There is increasing evidence to suggest that miRNAs play an important role in predicting cancer survival. To identify a panel of miRNA signature that can divided tumor from normal bladder using miRNA expression levels, and to assess the prognostic value of this specific miRNA markers in bladder cancer (BCa).

METHODS

A comprehensive meta-review of published miRNA expression profiles that compared BCa and adjacent normal tissues was performed to determine candidate miRNAs as prognostic biomarkers for BCa. Vote-counting strategy and Robust Rank Aggregation method were used to identify significant meta-signature miRNAs.

RESULTS

We identified an eight-miRNA signature including three upregulated (miR-141, miR-200c, miR-21) and five downregulated (miR-145, miR-125, miR-199a, let-7c and miR-99a) miRNAs for the prediction of overall survival (OS) using TCGA dataset, and validated in our 48 BCa patients. X-tile plot was used to generate the optimum cut-off point and Kaplan-Meier method was used to calculate OS. A linear prognostic model of eight miRNAs was constructed and weighted by the importance scores from the supervised principal component method to divide patients into high- and low-risk groups. Patients assigned to the high-risk group were associated with poor OS compared with patients in the low-risk group (HR = 5.21, p < 0.001). Our validation cohort of 48 patients confirmed the panel of 8-miRNAs as a reliable prognostic tool for OS in patients with BCa (HR = 5.04, p < 0.001).

CONCLUSION

The present meta-analysis identified eight highly significant and consistently dysregulated miRNAs from 19 datasets. We also constructed an eight-miRNA signature which provided predictive and prognostic value that complements traditional clinicopathological risk factors.

Uncovering the clinical utility of miR-143, miR-145 and miR-224 for predicting the survival of bladder cancer patients following treatment

Accurate prognosis is a key factor in establishing optimal therapeutic decisions; yet in the case of bladder cancer (BlCa) current prognostic indicators cannot ensure optimal disease management. Here, we aimed to evaluate the previously unexplored clinical potential of the urological cancer-related miR-145, miR-143 and miR-224 in BlCa. A total of 279 bladder tissue specimens were included in this study (133 BlCa, 107 adjacent normal and 39 healthy samples). Total RNA was extracted from tissues, it was polyadenylated and reverse transcribed to cDNA. The expression of target molecules was measured via quantitative real-time PCR. The expression levels of both miR-143 and miR-145 were significantly decreased, whereas those of miR-224 were increased in BlCa. Receiver operating characteristic curve analysis indicated a significant discriminatory capacity for miR-143/miR-145 levels. Important associations with disease aggressiveness were observed for all three microRNAs; elevated levels were observed in tumors of higher stage and grade, as well as in 'high-risk' TaT1 patients. More importantly, high miR-143/145 levels could effectively prognose inferior overall survival for muscle-invasive patients and could independently predict the progression of superficial tumors. Finally, the combination of miR-143/145 overexpression with the widely used prognostic markers of European Organization for Research and Treatment of Cancer-risk groups or recurrence at the first follow-up cystoscopy resulted to a superior positive prediction of non-muscle-invasive bladder cancer short-term progression compared with the use of the abovementioned markers alone. The cancer-related miR-143, miR-145 and miR-224 were investigated for the first time in the clinical setting of BlCa, and miR-143/145 cluster constitutes a novel marker helpful for providing an enhanced prediction of oncologic outcome for BlCa patients.

Regulation of IGF -1 signaling by microRNAs

The insulin-like growth factor 1 (IGF-1) signaling pathway regulates critical biological processes including development, homeostasis, and aging. Dysregulation of this pathway has been implicated in a myriad of diseases such as cancers, neurodegenerative diseases, and metabolic disorders, making the IGF-1 signaling pathway a prime target to develop therapeutic and intervention strategies. Recently, small non-coding RNA molecules in ∼22 nucleotide length, microRNAs (miRNAs), have emerged as a new regulator of biological processes in virtually all organ systems and increasing studies are linking altered miRNA function to disease mechanisms. A miRNA binds to 3'UTRs of multiple target genes and coordinately downregulates their expression, thereby exerting a profound influence on gene regulatory networks. Here we review the components of the IGF-1 signaling pathway that are known targets of miRNA regulation, and highlight recent studies that suggest therapeutic potential of these miRNAs against various diseases.

MiR-143 and MiR-145 regulate IGF1R to suppress cell proliferation in colorectal cancer

Insulin-like growth factor 1 receptor (IGF1R) is a transmembrane receptor that is activated by insulin-like growth factor 1 (IGF-1) and by a related hormone called IGF-2. It belongs to the large class of tyrosine kinase receptors and plays an important role in colorectal cancer etiology and progression. In this study, we used bioinformatic analyses to search for miRNAs that potentially target IGF1R. We identified specific target sites for miR-143 and miR-145 (miR-143/145) in the 3'-untranslated region (3'-UTR) of the IGF1R gene. These miRNAs are members of a cluster of miRNAs that have been reported to exhibit tumor suppressor activity. Consistent with the bioinformatic analyses, we identified an inverse correlation between miR-143/145 levels and IGF1R protein levels in colorectal cancer tissues. By overexpressing miR-143/145 in Caco2, HT29 and SW480 colorectal cancer cells, we experimentally validated that miR-143/145 directly recognizes the 3'-UTR of the IGF1R transcript and regulates IGF1R expression. Furthermore, the biological consequences of the targeting of IGF1R by miR-143/145 were examined by cell proliferation assays in vitro. We demonstrated that the repression of IGF1R by miR-143/145 suppressed the proliferation of Caco2 cells. Taken together, our findings provide evidence for a role of the miR-143/145 cluster as a tumor suppressor in colorectal cancer through the inhibition of IGF1R translation.