MicroRNA Expression Profiling in Clear Cell Renal Cell Carcinoma: Identification and Functional Validation of Key miRNAs

LncRNA GABPB1-IT1 inhibits the tumorigenesis of renal cancer via the miR-21/PTEN axis

Long noncoding RNA (lncRNA) (GABPB1-IT1) has been reported to be downregulated in lung cancer, while its expression and function in other cancers are unknown. In this study, the expression levels of GABPB1-IT1 in tissue samples from 62 ccRCC patients were measured by performing RT-qPCR. Potential base pairing formed between GABPB1-IT1 and miR-21 was explored using the online program IntaRNA 2.0 and further confirmed by Dual-luciferase activity assay and RNA pulldown assay. The role of GABPB1-IT1 and miR-21 in regulating the expression of PTEN was evaluated by RT-qPCR and Western blot. The role of GABPB1-IT1, miR-21, and PTEN in regulating the proliferation of Caki-2 cells was explored by CCK-8 assay. It was observed that GABPB1-IT1 was downregulated in ccRCC and predicted poor survival. GABPB1-IT1 directly interacted with miR-21, while it did not regulate the expression of each other. Moreover, upregulation of PTEN, which is a target of miR-21, was observed in ccRCC cells with overexpression of GABPB1-IT1. Overexpression of GABPB1-IT1 and PTEN decreased the proliferation rates of ccRCC cells. In addition, overexpression of GABPB1-IT1 reduced the enhancing effects of miR-21 on cell proliferation. Therefore, GABPB1-IT1 may upregulate PTEN by sponging miR-21 in ccRCC to inhibit cancer cell proliferation. Our study characterized a novel GABPB1-IT1/miR-21/PTEN axis in ccRCC.

MicroRNA-452: a double-edged sword in multiple human cancers

MicroRNAs (miRNAs) are small, noncoding RNAs with important functions in development, cell differentiation, and regulation of cell cycle and apoptosis. MiRNA expression is deregulated in various pathological processes including tumorigenesis and cancer progression through various mechanisms including amplification or deletion of miRNA genes, mutations, and epigenetic silencing and defects in the miRNA biogenesis machinery. Several studies have now shown abnormal miRNA profiles and proved their involvement in the initiation and progression of cancer. Since miR-452 has diverse roles (as suppressor or oncogene) in different cellular processes including epithelial-mesenchymal transition (EMT), proliferation, migration, and invasion, in this review we highlight a brief overview of the biological function and regulatory mechanism of miR-452 and its involvement as a potential biomarker for diagnosis and treatment of various cancer types.

Pan-cancer analysis of mRNA stability for decoding tumour post-transcriptional programs

Measuring mRNA decay in tumours is a prohibitive challenge, limiting our ability to map the post-transcriptional programs of cancer. Here, using a statistical framework to decouple transcriptional and post-transcriptional effects in RNA-seq data, we uncover the mRNA stability changes that accompany tumour development and progression. Analysis of 7760 samples across 18 cancer types suggests that mRNA stability changes are ~30% as frequent as transcriptional events, highlighting their widespread role in shaping the tumour transcriptome. Dysregulation of programs associated with >80 RNA-binding proteins (RBPs) and microRNAs (miRNAs) drive these changes, including multi-cancer inactivation of RBFOX and miR-29 families. Phenotypic activation or inhibition of RBFOX1 highlights its role in calcium signaling dysregulation, while modulation of miR-29 shows its impact on extracellular matrix organization and stemness genes. Overall, our study underlines the integral role of mRNA stability in shaping the cancer transcriptome, and provides a resource for systematic interrogation of cancer-associated stability pathways.

The role of mRNA stability in shaping the cancer transcriptome is revealed using a statistical analysis of transcriptomic data.

LINC00174 promotes cell proliferation and metastasis in renal clear cell carcinoma by regulating miR-612/FOXM1 axis

BACKGROUND

Kidney renal clear cell carcinoma (KIRC) is the most common pathological subtype of kidney tumor. Reportedly, LINC00174 is a key regulator in cancer progression. This study aims to clarify the role and molecular mechanism of LINC00174 in the progression of KIRC.

METHODS

LINC00174 expression in KIRC and its prognostic value were analyzed by bioinformatics. LINC00174, miR-612 and FOXM1 mRNA expression levels in KIRC clinical samples and cell lines were detected by qRT-PCR. After LINC00174 was overexpressed or knocked down, CCK-8, BrdU and Transwell assays were adopted to evaluate the proliferation and metastatic potential of KIRC cells. Bioinformatics and dual luciferase reporter assays were employed to validate the targeting relationship between miR-612 and LINC00174 or FOXM1 mRNA, respectively. Western blot assay was performed to detect FOXM1 protein expression in KIRC cells.

RESULTS

LINC00174 expression and FOXM1 expression were up-regulated in 42 cases of KIRC tissues (P < 0.001), while miR-612 expression was down-regulated (P < 0.001). LINC00174 overexpression or miR-612 inhibitor promoted the viability and proliferation of KIRC cells (P < 0.01). Migration and invasion of KIRC cells were promoted when the cells were transfected with LINC00174 overexpression or miR-612 inhibitor (P < 0.05). LINC00174 can competitively bind with miR-612 to repress the expression of miR-612, in turn up-regulate the expression of FOXM1 mRNA.

CONCLUSION

LINC00174 facilitates the proliferation and metastatic potential of KIRC cells via regulating the miR-612/FOXM1 axis.

Circulating microRNAs from the Molecular Mechanisms to Clinical Biomarkers: A Focus on the Clear Cell Renal Cell Carcinoma

microRNAs (miRNAs) are emerging as relevant molecules in cancer development and progression. MiRNAs add a post-transcriptional level of control to the regulation of gene expression. The deregulation of miRNA expression results in changing the molecular circuitry in which miRNAs are involved, leading to alterations of cell fate determination. In this review, we describe the miRNAs that are emerging as innovative molecular biomarkers from liquid biopsies, not only for diagnosis, but also for post-surgery management in cancer. We focus our attention on renal cell carcinoma, in particular highlighting the crucial role of circulating miRNAs in clear cell renal cell carcinoma (ccRCC) management. In addition, the functional deregulation of miRNA expression in ccRCC is also discussed, to underline the contribution of miRNAs to ccRCC development and progression, which may be relevant for the identification and design of innovative clinical strategies against this tumor.

The miR-199a/214 Cluster Controls Nephrogenesis and Vascularization in a Human Embryonic Stem Cell Model

MicroRNAs (miRNAs) are gene expression regulators and they have been implicated in acquired kidney diseases and in renal development, mostly through animal studies. We hypothesized that the miR-199a/214 cluster regulates human kidney development. We detected its expression in human embryonic kidneys by in situ hybridization. To mechanistically study the cluster, we used 2D and 3D human embryonic stem cell (hESC) models of kidney development. After confirming expression in each model, we inhibited the miRNAs using lentivirally transduced miRNA sponges. This reduced the WT1+ metanephric mesenchyme domain in 2D cultures. Sponges did not prevent the formation of 3D kidney-like organoids. These organoids, however, contained dysmorphic glomeruli, downregulated WT1, aberrant proximal tubules, and increased interstitial capillaries. Thus, the miR-199a/214 cluster fine-tunes differentiation of both metanephric mesenchymal-derived nephrons and kidney endothelia. While clinical implications require further study, it is noted that patients with heterozygous deletions encompassing this miRNA locus can have malformed kidneys.

MiR-125b promotes migration and invasion by targeting the vitamin D receptor in renal cell carcinoma

Purpose: To investigate the expression of miR-125b and vitamin D receptor (VDR) in renal cell carcinoma (RCC) and assess the biological function of miR-125b in RCC. Methods: We used quantitative real-time polymerase chain reaction (RT-PCR) to detect the expression of nucleic acids and western blotting to analyze the protein abundance in RCC cell lines. MiR-125b mimic and inhibitor were employed to investigate the function and behavior of miR-125b in RCC cell lines. The relationship between miR-125 and VDR was verified using luciferase assays. Results: Overexpression of miR-125b promoted migration and invasion and prevent cell apoptosis in ACHN cells. In contrast, miR-125b deficiency suppressed migration and invasion and induced cell apoptosis in 786-O cells. Luciferase assays indicated the interaction between miR-125b and VDR. In collected samples, miR-125b was significantly higher in RCC tissues and negatively correlated to VDR (r=-0.444, p=0.04). Conclusion: MiR-125b displays an oncogene profile in RCC, patients with high expression of miR-125b should be a more frequent follow-up. MiR-125B may be a potential therapeutic target for RCC.

MicroRNA Signature in Renal Cell Carcinoma

Renal cell carcinoma (RCC) includes 2.2% of all diagnosed cancers and 1.8% of cancer-related mortalities. The available biomarkers or screening methods for RCC suffer from lack of sensitivity or high cost, necessitating identification of novel biomarkers that facilitate early diagnosis of this cancer especially in the susceptible individuals. MicroRNAs (miRNAs) have several advantageous properties that potentiate them as biomarkers for cancer detection. Expression profile of miRNAs has been assessed in biological samples from RCC patients. Circulatory or urinary levels of certain miRNAs have been proposed as markers for RCC diagnosis or follow-up. Moreover, expression profile of some miRNAs has been correlated with response to chemotherapy, immunotherapy or targeted therapeutic options such as sunitinib. In the current study, we summarize the results of studies that assessed the application of miRNAs as biomarkers, therapeutic targets or modulators of response to treatment modalities in RCC patients.

MiR-125b-2-3p associates with prognosis of ccRCC through promoting tumor metastasis via targeting EGR1

Clear cell renal cell carcinoma (ccRCC) is an aggressive tumor with frequent metastatic rate. In order to explore the mechanisms, we determined the roles of miR-125b-2-3p in metastatic ccRCC progression. In the study, both clinical and experimental evidences supported the critical role of miR-125b-2-3p in accelerating ccRCC metastasis. Elevated miR-125b-2-3p expression correlated with lymphatic invasion, distant metastasis and poor survival. Functional study showed that high miR-125b-2-3p expression significantly increased ccRCC cell migration in vitro and lung metastasis in vivo. Furthermore, we demonstrated that miR-125b-2-3p directly targeted EGR1, and miR-125b-2-3p accelerated ccRCC cell migration through down-regulating EGR1. Taken together, this study demonstrated that miR-125b-2-3p associates with ccRCC prognosis via promoting tumor metastasis through targeting EGR1.

MIR205HG acts as a ceRNA to expedite cell proliferation and progression in lung squamous cell carcinoma via targeting miR-299-3p/MAP3K2 axis

INTRODUCTION

Long noncoding RNAs (lncRNAs) have been associated with many types of cancers, but their molecular mechanisms in lung squamous cell carcinoma (LUSC) have not been fully studied. Therefore, the current study investigated the regulation role of microRNA-205 host gene (MIR205HG) in LUSC and recognized the target genes managed by this lncRNA.

METHODS

MIR205HG expression was assessed by the quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The effects of silenced MIR205HG on cell biological behaviors were detected by colony formation assay, transwell assay, flow cytometry analysis and western blot analysis. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were utilized to proof the binding relationship between miR-299-3p and MIR205HG/mitogen-activated protein kinase kinase kinase 2 (MAP 3 K2).

RESULTS

The expression levels of MIR205HG in LUSC tissues and cell lines were obviously up-regulated. Down-regulation of MIR205HG expression remarkably reduced cell proliferation, migration and epithelial-to-mesenchymal transition (EMT) progression, whereas promoted cell apoptosis. MIR205HG could bind with miR-299-3p and down-regulation of MIR205HG elevated miR-299-3p expression. MAP 3 K2 acted as the target gene of miR-299-3p and was up-regulated by MIR205HG overexpression. Overexpressing MAP 3 K2 could counteract the effects of down-regulating MIR205HG on LUSC progression to some degree.

CONCLUSION

MIR205HG acts as a competing endogenous RNA (ceRNA) to expedite cell proliferation and progression via targeting miR-299-3p in LUSC.

Inhibition of TUG1/miRNA-299-3p Axis Represses Pancreatic Cancer Malignant Progression via Suppression of the Notch1 Pathway

BACKGROUND AND AIMS

Taurine-upregulated gene 1 (TUG1) is reported to be upregulated and contributes to the progression of Pancreatic cancer (PC) by serving as an oncogene. Our aims were to explore the precise mechanism of TUG1 involved in PC pathogenesis.

METHODS

TUG1 and miR-299-3p expression profiles were measured by qRT-PCR. The direct interaction between TUG1 and miR-299-3p was explored by luciferase reporter assay. MTT assay, flow cytometry analysis, caspase-3 activity assay, Transwell invasion assay and wound healing assay were performed to evaluate cell proliferative ability, apoptosis, caspase-3 activity, invasion and migration, respectively. Western blot was conducted to examine the expressions of Ki67, Bax, Bcl-2, matrix metalloproteinase-2 (MMP-2), MMP-9, E-cadherin, N-cadherin, Snail, Notch1, Survivin, and CyclinD1. In addition, animal experiments were also implemented.

RESULTS

TUG1 was highly expressed, while miR-299-3p was underexpressed in PC tissues and PC cells. Furthermore, the significant increase of TUG1 in PC tissues of advanced patients (stage 3/4) was observed compared to patients (stage 1/2). TUG1 was negatively correlated with miR-299-3p expression in PC tissues. Moreover, TUG1 functioned as a molecular sponge of miR-299-3p to repress its expression. TUG1 knockdown suppressed cell proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT), and induced apoptosis in PC cells, and repressed tumor growth and EMT in PC xenograft models, which were reversed following reintroduction with anti-miR-299-3p. Furthermore, we found that TUG1 silencing inactivated the Notch1 pathway in PC by upregulating miR-299-3p.

CONCLUSIONS

The results reported that inhibition of TUG1/miR-299-3p axis suppressed PC malignant progression via suppression of the Notch1 pathway.

miR-429-CRKL axis regulates clear cell renal cell carcinoma malignant progression through SOS1/MEK/ERK/MMP2/MMP9 pathway

The pathogenesis and tumorigenesis of clear cell renal cell carcinoma (ccRCC) remain unclear. The deregulations of miR-429, a member of miR-200 family, and v-crk sarcoma virus CT10 oncogene homologue (avian)-like (CRKL), an adaptor protein of CRK family, are involved in the development, metastasis and prognosis of various cancers. Current study aimed to demonstrate the differential expressions of miR-429 and CRKL with their correlationship and molecular regulation mechanism in ccRCC malignancy. miR-429 and CRKL separately showed suppressing and promoting effects in ccRCC. Lower miR-429 expression and higher CRKL expression were negatively correlated in surgical cancerous tissues by promoting the advance of ccRCC. By binding to the 3'-UTR of CRKL, miR-429 reversely regulated CRKL for its functionalities in ccRCC cells. CRKL knockdown and overexpression separately decreased and increased the in vitro migration and invasion of 786-O cells, which were consistent with the influences of miR-429 overexpression and knockdown on 786-O through respectively downregulating and upregulating CRKL via SOS1/MEK/ERK/MMP2/MMP9 pathway. The enhancements of CRKL expression, migration and invasion abilities and SOS1/MEK/ ERK/MMP2/MMP9 activation induced by TGF-β stimulation in 786-O cells could be antagonized by miR-429 overexpression. Exogenous re-expression of CRKL abrogated miR-429 suppression on the migration and invasion of 786-O cells. Collectively, miR-429 deficiency negatively correlated with CRKL overexpression promoted the aggressiveness of cancer cells and advanced the clinical progression of ccRCC patients. miR-429-CRKL axial regulation provides new clues to the fundamental research, diagnosis and treatment of ccRCC.

PGC1α suppresses kidney cancer progression by inhibiting collagen-induced SNAIL expression

The transcriptional events that promote invasive and metastatic phenotypes in renal cell carcinoma (RCC) remain poorly understood. Here we report that the decreased expression of peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC1α) and the increased expression of several genes encoding collagen family members are associated with RCC tumor progression. PGC1α restoration attenuates invasive phenotypes and suppresses tumor progression in vivo. In contrast, collagens produced by RCC cells promote invasive and migratory phenotypes. PGC1α restoration suppresses the expression of collagens and tumor phenotypes via the induction of miR-29a. Furthermore, decreased collagens via the PGC1α/miR-29a axis suppresses collagen-mediated activation of discoidin domain receptor 1 (DDR1)/ERK signaling. In turn, the suppression of collagen/DDR1 signaling by PGC1α leads to decreased levels of the known EMT regulators SNAIL1 and 2. Collectively, our results demonstrate a novel role for PGC1α in the regulation of proinvasive SNAIL proteins.

Knockdown of circ_0084043 suppresses the development of human melanoma cells through miR-429/tribbles homolog 2 axis and Wnt/β-catenin pathway

AIMS

Circular RNAs (circRNAs) have been emerged as novel regulators in multiple tumorigenesis, including melanoma. CircRNA_0084043 was recently demonstrated to be deregulated in human melanoma cells. Nevertheless, its role and mechanism are largely unrevealed in melanoma.

MATERIALS AND METHODS

Expression of circ_0084043, miRNA (miR)-429 and tribbles homolog 2 (TRIB2) was detected using reverse transcription-quantitative PCR quantitative PCR (RT-qPCR) and western blotting. Cell proliferation, apoptosis, migration and invasion were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry and transwell assays, respectively. The activation of Wnt/β-catenin pathway was evaluated by western blotting. The target binding among circ_0084043, miR-429 and TRIB2 was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation. In vivo, mice xenograft model was generated to investigate tumor growth.

KEY FINDINGS

Expression of circ_0084043 and TRIB2 was upregulated in human melanoma tissues and cell lines. Both circ_0084043 knockdown and TRIB2 silencing could decrease cell proliferation, migration and invasion, but facilitate apoptosis in A375 and SK-MEL-28 cells. Furthermore, TRIB2 restoration partially abrogated the tumor-suppressive role of circ_0084043 knockdown in melanoma cells in vitro. Then, we verified that circ_0084043 positively and physically controlled TRIB2 expression through sponging miR-429. Besides, expression of β-catenin, c-Myc and cyclinD1 was inhibited in A375 and SK-MEL-28 cells when circ_0084043 was knocked down, accompanied with increased miR-429 and decreased TRIB2. Notably, circ_0084043 downregulation impeded tumor growth of A375 cells in vivo.

SIGNIFICANCE

Knockdown of circ_0084043 suppressed the malignant development of melanoma presumably through modulating miR429/TRIB2 axis and inactivating Wnt/β-catenin signaling pathway.

MicroRNA-532 exerts oncogenic functions in t(4;14) multiple myeloma by targeting CAMK2N1

Multiple myeloma (MM) is a plasma cell neoplasm which is characterized by widespread genetic heterogeneity. The MMs with t(4;14) translocation exhibit poor outcomes. However, the mechanism underlying has not been well dissected. Our study aimed to identify key microRNA involved in the oncogenesis of t(4;14) MM. We here performed an integrated analysis to screen important regulators in the pathogenesis of t(4;14) MM. We used real-time quantitative polymerase chain reaction and western blotting to evaluate the mRNA and protein expression of the indicated microRNA or protein. Cell proliferation assay, colony formation assay, and transwell assay were used to examine the cell growth and metastasis. More importantly, the tumor growth and metastasis were analyzed in nude mice injected with MM cells. The integrated analysis indicated that miR-532 functioned as a pivotal regulator in t(4;14) MM. miR-532 was upregulated in t(4;14) MMs and promotes cell growth and metastasis in vitro and in vivo. Notably, though combing bioinformatics analysis and functional assays, CAMK2N1 was revealed as a functional target of miR-532 in MM cells. CAMK2N1 plays an anti-proliferative and anti-migration role in MM cells, and miR-532 exerts its oncogenic role though inhibiting CAMK2N1 expression in MMs. miR-532 promotes cell proliferation and invasion in t(4;14) MMs by targeting CAMK2N1. Our study, thus, provides possible targets for t(4;14) MM therapy.

Molecular Mechanisms in Clear Cell Renal Cell Carcinoma: Role of miRNAs and Hypermethylated miRNA Genes in Crucial Oncogenic Pathways and Processes

Clear cell renal cell carcinoma (ccRCC) is the third most common urological cancer, and it has the highest mortality rate. The increasing drug resistance of metastatic ccRCC has resulted in the search for new biomarkers. Epigenetic regulatory mechanisms, such as genome-wide DNA methylation and inhibition of protein translation by interaction of microRNA (miRNA) with its target messenger RNA (mRNA), are deeply involved in the pathogenesis of human cancers, including ccRCC, and may be used in its diagnosis and prognosis. Here, we review oncogenic and oncosuppressive miRNAs, their putative target genes, and the crucial pathways they are involved in. The contradictory behavior of a number of miRNAs, such as suppressive and anti-metastatic miRNAs with oncogenic potential (for example, miR-99a, miR-106a, miR-125b, miR-144, miR-203, miR-378), is examined. miRNAs that contribute mostly to important pathways and processes in ccRCC, for instance, PI3K/AKT/mTOR, Wnt-β, histone modification, and chromatin remodeling, are discussed in detail. We also separately consider their participation in crucial oncogenic processes, such as hypoxia and angiogenesis, metastasis, and epithelial-mesenchymal transition (EMT). The review also considers the interactions of long non-coding RNAs (lncRNAs) and miRNAs of significance in ccRCC. Recent advances in the understanding of the role of hypermethylated miRNA genes in ccRCC and their usefulness as biomarkers are reviewed based on our own data and those available in the literature. Finally, new data and perspectives concerning the clinical applications of miRNAs in the diagnosis, prognosis, and treatment of ccRCC are discussed.

A genetic variant located in the miR-532-5p-binding site of TGFBR1 is associated with the colorectal cancer risk

BACKGROUND

Genome-wide association studies have identified genes in the transforming growth factor-β (TGFβ) signaling pathway that are responsible for regulating carcinogenesis.

METHODS

We searched for single-nucleotide polymorphisms (SNPs) located within 3'-untranslated regions (3'-UTRs) that might affect the ability of miRNAs to bind genes in the TGFβ pathway for further analysis. We used TaqMan technology to genotype these SNPs in a population-based case-control study of 1147 colorectal cancer patients and 1203 matched controls in a Chinese population.

RESULTS

The rs1590 variant of TGFBR1 exhibited a significant association with colorectal cancer risk. Compared with individuals carrying the rs1590 TT genotype, individuals carrying the GT/GG genotypes had a decreased risk of colorectal cancer [odd ratio (OR) = 0.82, 95% confidence interval (CI) = 0.68-0.97], which was more evident among older individuals with a family history of cancer. Luciferase assays confirmed that the rs1590 T allele altered the capacity of miR-532-5p to bind TGFBR1.

CONCLUSIONS

Based on these findings, the rs1590 variant in the 3'-UTR of TGFBR1 may contribute to the susceptibility to colorectal cancer, predominantly by altering miR-532-5p binding.

Dysregulation of ncRNAs located at the DLK1‑DIO3 imprinted domain: involvement in urological cancers

Genomic imprinting has been found to be involved in human physical development and several diseases. The DLK1-DIO3 imprinted domain is located on human chromosome 14 and contains paternally expressed protein-coding genes (DLK1, RTL1, DIO3) and numerous maternally expressed ncRNA genes (MEG3, MEG8, antisense RTL1, miRNAs, piRNAs, and snoRNAs). Emerging evidence has implicated that dysregulation of the DLK1-DIO3 imprinted domain especially the imprinted ncRNAs is critical for tumor progressions. Multiple miRNAs and lncRNAs have been investigated in urological cancers, of which several are transcribed from this domain. In this review, we present current data about the associated miRNAs, lncRNAs, and piRNAs and the regulation of differentially methylated regions methylation status in the progression of urological cancers and preliminarily propose certain concepts about the potential regulatory networks involved in DLK1-DIO3 imprinted domain.

Global and Targeted miRNA Expression Profiling in Clear Cell Renal Cell Carcinoma Tissues Potentially Links miR-155-5p and miR-210-3p to both Tumorigenesis and Recurrence

About 30% of patients undergoing nephrectomy for renal cell carcinoma (RCC) experience disease recurrence. We profiled miRNAs dysregulated in clear-cell (cc) RCC tumor tissues and predictive of recurrence. The expression levels of 800 miRNAs were assessed in paired tumor and normal tissues from a discovery cohort of 18 ccRCC patients. miRNAs found to be differentially expressed were examined in a validation set of 205 patients, using real-time quantitative PCR. Tumor-normal data from 64 patients in The Cancer Genome Atlas were used for external validation. Twenty-eight miRNAs were consistently dysregulated in tumor tissues. On dichotomized analysis, patients with high levels of miR-155-5p and miR-210-3p displayed an increased risk for ccRCC recurrence (hazard ratio, 2.64; 95% CI, 1.49 to 4.70; P = 0.0009; and hazard ratio, 1.80; 95% CI, 1.04 to 3.12; P = 0.036, respectively) and a shorter median recurrence-free survival time than did patients with low levels [P < 0.01 (log rank test)]. A risk score was generated based on the expression levels of miR-155-5p and miR-210-3p, and the trend test was significant (P = 0.005). On pathway analysis, target genes regulated by miR-155-5p and miR-210-3p were mainly enriched in inflammation-related pathways. We identified and validated multiple miRNAs dysregulated in ccRCC tissues; miR-155-5p and miR-210-3p were predictive of ccRCC recurrence, pointing to potential utility as biomarkers and underlying biological mechanisms.

miR-487a promotes progression of gastric cancer by targeting TIA1

Gastric cancer (GC) is one of the most common malignancies as well as the third leading cause for cancer-related death. Molecular basis of GC are essential and critical for its therapeutic treatment, but still remain poorly understood. T-cell intracellular antigen-1 (TIA1) extensively involves in cancer progression, whereas its role and regulation mechanism in GC have not been revealed. In the present study, we found that TIA-1 protein level was down-regulated in GC tissues and TIA1 inhibited proliferation and promoted apoptosis of GC cells. Then, we used bioinformatics to predict miR-487a as the upstream regulator of TIA1 and we also observed an inverse correlation between miR-487a level and TIA-1 protein level in GC tissues. Next, we demonstrated that miR-487a directly targeted TIA1 via binding to its 3'-untranslated region. Furthermore, we investigated the role of miR-487a-TIA1 pathway in the growth of GC cells both in vitro and in vivo. The repression of TIA-1 by miR-487a promoted cell proliferation and suppressed cell apoptosis in vitro, and the knockdown of miR-487a had the opposite effects. Finally, we demonstrated that miR-487a promoted the development of gastric tumor growth in xenograft mice by targeting TIA-1. These effects could be partially reversed by restoring the expression of TIA-1. Overall, our results reveal that TIA1 is a tumor suppressor gene and is directly regulated by miR-487a in GC, which may offer new therapeutic targets for GC treatment.

Ankyrin repeat and single KH domain 1 (ANKHD1) drives renal cancer cell proliferation via binding to and altering a subset of miRNAs

Clear cell renal cell carcinoma (ccRCC) represents the most common kidney cancer worldwide. Increased cell proliferation associated with abnormal microRNA (miRNA) regulation are hallmarks of carcinogenesis. Ankyrin repeat and single KH domain 1 (ANKHD1) is a highly conserved protein found to interact with core cancer pathways in Drosophila; however, its involvement in RCC is completely unexplored. Quantitative PCR studies coupled with large-scale genomics data sets demonstrated that ANKHD1 is significantly up-regulated in kidneys of RCC patients when compared with healthy controls. Cell cycle analysis revealed that ANKHD1 is an essential factor for RCC cell division. To understand the molecular mechanism(s) utilized by ANKHD1 to drive proliferation, we performed bioinformatics analyses that revealed that ANKHD1 contains a putative miRNA-binding motif. We screened 48 miRNAs with tumor-enhancing or -suppressing activities and found that ANKHD1 binds to and regulates three tumor-suppressing miRNAs (i.e. miR-29a, miR-205, and miR-196a). RNA-immunoprecipitation assays demonstrated that ANKHD1 physically interacts with its target miRNAs via a single K-homology domain, located in the C terminus of the protein. Functionally, we discovered that ANKHD1 positively drives ccRCC cell mitosis via binding to and suppressing mainly miR-29a and to a lesser degree via miR-196a/205, leading to up-regulation in proliferative genes such as CCDN1. Collectively, these data identify ANKHD1 as a new regulator of ccRCC proliferation via specific miRNA interactions.

Expanding the Utilization of Formalin-Fixed, Paraffin-Embedded Archives: Feasibility of miR-Seq for Disease Exploration and Biomarker Development from Biopsies with Clear Cell Renal Cell Carcinoma

Novel predictive tools for clear cell renal cell carcinoma (ccRCC) are urgently needed. MicroRNAs (miRNAs) have been increasingly investigated for their predictive value, and formalin-fixed paraffin-embedded biopsy archives may potentially be a valuable source of miRNA sequencing material, as they remain an underused resource. Core biopsies of both cancerous and adjacent normal tissues were obtained from patients (n = 12) undergoing nephrectomy. After small RNA-seq, several analyses were performed, including classifier evaluation, obesity-related inquiries, survival analysis using publicly available datasets, comparisons to the current literature and ingenuity pathway analyses. In a comparison of tumour vs. normal, 182 miRNAs were found with significant differential expression; miR-155 was of particular interest as it classified all ccRCC samples correctly and correlated well with tumour size (R² = 0.83); miR-155 also predicted poor survival with hazard ratios of 2.58 and 1.81 in two different TCGA (The Cancer Genome Atlas) datasets in a univariate model. However, in a multivariate Cox regression analysis including age, sex, cancer stage and histological grade, miR-155 was not a statistically significant survival predictor. In conclusion, formalin-fixed paraffin-embedded biopsy tissues are a viable source of miRNA-sequencing material. Our results further support a role for miR-155 as a promising cancer classifier and potentially as a therapeutic target in ccRCC that merits further investigation.

microRNA-302c-3p inhibits renal cell carcinoma cell proliferation by targeting Grb2-associated binding 2 (Gab2)

The expression and biological function of Grb2-associated binding 2 (Gab2) in renal cell carcinoma (RCC) cells was tested here. We showed that Gab2 expression was significantly elevated in human RCC tissues and RCC cells. It was correlated with over-activation of Akt and downregulation of microRNA-302c-3p ("miR-302c-3p"), a putative Gab2-targeting microRNA. Knockdown of Gab2 inhibited Akt activation and 786-O RCC cell proliferation. Reversely, forced over-expression of Gab2 led to Akt hyper-activation to facilitate 786-O cell proliferation. Exogenous expression of miR-302c caused Gab2 downregulation, Akt inhibition and 786-O cell proliferation inhibition. On the other hand, miR-302c-3p depletion by expressing its anti-sense ("antagomiR-302c") led to Gab2 upregulation, Akt activation and increased 786-O cell proliferation. Significantly, miR-302c-3p failed to affect the proliferation of 786-O cells with shRNA-depleted Gab2. Together, we suggest that miR-302c-3p depletion in human RCC cells leads to Gab2 over-expression, Akt hyper-activation and cell proliferation.

MicroRNA-452 promotes stem-like cells of hepatocellular carcinoma by inhibiting Sox7 involving Wnt/β-catenin signaling pathway

The decrease of microRNA-452 (miR-452) in gliomas promoted stem-like features and tumorigenesis. However, the role of miR-452, especially in regulating cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) remains ambiguous. We enriched stem-like HCC cells by serial passages of hepatospheres with chemotherapeutic agents. Stem-like characteristics including the capabilities of chemo-resistance, stemness-related gene expression profiling, self-renewal, tumorigenicity and metastasis formation were detected. MiR-452 was markedly increased in the chemo-resistant hepatospheres and human HCC tissues. and the overexpression of miR-452 in HCC patients predicted poor overall survival. MiR-452 significantly promoted stem-like characteristics in vitro and in vivo. Further, Sox7 was identified as the direct target of miR-452, which could physically bind with β-catenin and TCF4 in the nucleus and then inhibit the activity of Wnt/β-catenin signaling pathway. Finally, the combined chemotherapy of doxorubicin and all-trans retinoic acid (ATRA) showed dramatically efficiency in suppressing HCC metastasis. These data suggested that miR-452 promoted stem-like traits of HCC, which might be a potential therapeutic target for HCC. The combination of doxorubicin and ATRA might be a promising therapy in HCC management.

The biological roles and clinical implications of microRNAs in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) accounts for about 3% of tumors in adults as well as 85% of all primary renal carcinoma. And it is the third most predominant urological carcinoma, but it has the maximum mortality rate. Early diagnosis and proper follow-up of ccRCC patients may improve the prognosis of the illness. Thus, it is imperative to understand the new biomarkers of ccRCC and study new method for the modern therapy of this deadly disease. Furthermore, a large number of microRNAs (miRNAs), small non-coding RNAs, have been relevant to tumor type, stage, or survival and miRNAs might be progressed as the markers of diagnosis or prognosis in ccRCC. A growing body of data also advised the rationality of regarding miRNAs as therapeutic targets for ccRCC treatment. In this review, we tried to summarize biogenesis of miRNAs and their expression profiles, biological roles, and clinical implications in ccRCC.

Long non-coding RNA H19 regulates E2F1 expression by competitively sponging endogenous miR-29a-3p in clear cell renal cell carcinoma

Background

Numerous recent studies indicate that the long non-coding RNAs (lncRNAs) are frequently abnormal expressed and take critical roles in many cancers. Renal cell carcinoma is the secondary malignant tumors in the urinary system and has high mortality and morbidity. Around 80% of RCCs is clear cell renal cell carcinoma (ccRCC) and is characterized by high metastasis and relapse rate. However, the clinical significances of lncRNAs in ccRCC are still unknown.

Methods

The human cancer lncRNA PCR array (Yingbio) was performed to detect the differentially expressed lncRNAs in human ccRCC samples. Real-time PCR (RT-PCR), dual-luciferase assay, RNA binding protein immunoprecipitation (RIP) assay, transwell assay, CCK-8 assay, and western blot were performed to explore the molecular mechanism of lncRNAs in ccRCC cell migration and invasion.

Results

In this study, lncRNA-H19 was high expressed and negatively correlated with miR-29a-3p in ccRCC. By bioinformatics software, dual-luciferase reporter and RIP assays, we verified that miR-29a-3p was identified as a direct target of lncRNA-H19. RT-PCR and western blot demonstrated that down-regulated lncRNA-H19 could affect the expression of miR-29a-3p targeting E2F1 with competitively binding miR-29a-3p. Furthermore, transwell assays indicated that lncRNA-H19 knockdown inhibited cells migration and invasion, but this effect was attenuated by co-transfection of lncRNA-H19 siRNA and miR-29a-3p inhibitor. Over expression of E2F1 could rescue lncRNA-H19 siRNA induced suppression on cell migration and invasion in ccRCC cells.

Conclusions

These results show a possible competing endogenous RNAs regulatory network involving lncRNA-H19 regulates E2F1 expression by competitively sponging endogenous miR-29a-3p in ccRCC. This mechanism may contribute to a better understanding of ccRCC pathogenesis, and lncRNA-H19 may be further considered as a potential therapeutic target for ccRCC intervention.

Plasma exosomal miRNAs-based prognosis in metastatic kidney cancer

Plasma exosomal miRNAs were evaluated for prognosis in an initial set of 44 metastatic renal cell cancer (mRCC) patients by RNA sequencing. Among ∼3.49 million mappable reads per patient, miRNAs accounted for 93.1% of the mapped RNAs. 227 miRNAs with high abundance were selected for survival analysis. Cox regression analysis identified association of 6 miRNAs with overall survival (OS) (P<0.01, False discovery rate (FDR) < 0.3). Five of the associated miRNAs were quantified in an independent follow-up cohort of 65 mRCC patients by TaqMan-based miRNA assays. Kaplan-Meier analysis confirmed the significant OS association of three miRs; miR-let-7i-5p (P=0.018, HR=0.49, 95% CI=0.21-0.84), miR-26a-1-3p (P=0.025, HR=0.43, 95% CI=0.10-0.84) and miR-615-3p (P=0.0007, HR=0.36, 95% CI=0.11-0.54). A multivariate analysis of miR-let-7i-5p with the clinical factor-based Memorial Sloan-Kettering Cancer Center (MSKCC) score improved survival prediction from an area under the curve (AUC) of 0.58 for MSKCC score to an average AUC of 0.64 across 48-month follow-up time. The multivariate model was able to define a high-risk group with median survival of 14 months and low risk group of 39 months (P=0.0002, HR=3.43, 95%CI, 2.73-24.15). Further validation of miRNA-based prognostic biomarkers are needed to improve current clinic-pathologic based prognostic models in patients with mRCC.

A three-microRNA signature as a diagnostic and prognostic marker in clear cell renal cancer: An In Silico analysis

Accumulating evidence has demonstrated that some specific miRNAs were aberrantly expressed in renal clear cell carcinoma and participated in many biological processes. The aim of this study was to investigate a panel of miRNA signature for diagnosis and prognosis of renal clear cell carcinoma (KIRC). Here, we performed a comprehensive analysis for miRNA expression profiles and corresponding clinical information of 516 KIRC patients from The Cancer Genome Atlas (TCGA). In the study, a total of 63 differentially expressed miRNAs were identified, of which 34 were up-regulated and 29 were down-regulated. We constructed a panel of three-miRNA that were significantly associated with KIRC diagnosis and KIRC patients' prognosis. The three-miRNA signature reached a sensitivity of 98.3% and a specificity of 97.2% in the diagnosis of KIRC. Using the three-miRNA signature, we classified the KIRC patients into high-risk group and low-risk group. The Kaplan- Meier curves showed that KIRC patients with high risk scores had significantly worsen overall survival (OS) and disease free survival (DFS) than KIRC patients with low risk scores. In the univariate and multivariate Cox regression analysis, three-miRNA signature was an independent prognostic factor in OS. In conclusion, the three-miRNA signature could be used as a diagnostic and prognostic biomarker in KIRC, and therefore, may help to provide significant clinical implication for the treatment of KIRC.

LINC00052 upregulates EPB41L3 to inhibit migration and invasion of hepatocellular carcinoma by binding miR-452-5p

Numerous studies have demonstrated that a class of long noncoding RNAs (lncRNAs) are dysregulated in hepatocellular carcinoma (HCC) and they are closely related with tumorigenesis. Our previous studies indicated that LINC00052 was a downregulated lncRNA in HCC and acted as a tumor suppressor gene. Using transcription microarray analysis, we found that knockdown of LINC00052 resulted in EPB41L3 downregulation. However, the function of EPB41L3 and the mechanism of LINC00052 downregulating EPB41L3 in HCC remain unclear. In this study, we found that overexpression of LINC00052 could upregulate the EPB41L3 expression and it might serve as a tumor suppressor gene in HCC. Database analysis showed that miR-452-5P could target LINC00052. The binding regions between LINC00052 and miR-452-5P were confirmed by luciferase assays. Moreover, LINC00052 inhibited cell malignant behavior by increasing miR-452-5P expression, suggesting that LINC00052 was negatively regulated by miR-452-5P. In addition, overexpression of miR-452-5P resulted in a decrease of EPB41L3 expression, suggesting that EPB41L3 was as a target of miR-452-5P. In conclusion, these results demonstrated that a novel pathway was mediated by LINC00052 in HCC.

Thyroid transcription factor-1-regulated microRNA-532-5p targets KRAS and MKL2 oncogenes and induces apoptosis in lung adenocarcinoma cells

Thyroid transcription factor‐1 (TTF‐1), also known as NKX2‐1, plays a role as a lineage‐survival oncogene in lung adenocarcinoma that possesses double‐edged sword characteristics. Although evidence from previous studies has steadily accumulated regarding the roles of TTF‐1 in transcriptional regulation of protein‐coding genes, little is known about its regulatory relationship with microRNAs. Here, we utilized an integrative approach designed to extract maximal information from expression profiles of both patient tumors in vivo and TTF‐1‐inducible cell lines in vitro, which identified microRNA (miR)‐532‐5p as a novel transcriptional target of TTF‐1. We found that miR‐532‐5p is directly regulated by TTF‐1 through its binding to a genomic region located 8 kb upstream of miR‐532‐5p, which appears to impose transcriptional regulation independent of that of CLCN5, a protein‐coding gene harboring miR‐532‐5p in its intron 3. Furthermore, our results identified KRAS and MKL2 as novel direct targets of miR‐532‐5p. Introduction of miR‐532‐5p mimics markedly induced apoptosis in KRAS‐mutant as well as KRAS wild‐type lung adenocarcinoma cell lines. Interestingly, miR‐532‐5p showed effects on MEK‐ERK pathway signaling, specifically in cell lines sensitive to siKRAS treatment, whereas those miR‐532‐5p‐mediated effects were clearly rendered as phenocopies by repressing expression or inhibiting the function of MKL2 regardless of KRAS mutation status. In summary, our findings show that miR‐532‐5p is a novel transcriptional target of TTF‐1 that plays a tumor suppressive role by targeting KRAS and MKL2 in lung adenocarcinoma.

miR-125b is associated with renal cell carcinoma cell migration, invasion and apoptosis

MicroRNA (miR)-125b has been identified as deregulated in a number of types of cancer. Previous studies have detected the expression of miR-125b in clear cell renal cell carcinoma (ccRCC) tissues by in situ hybridization and revealed that miR-125b was upregulated in ccRCC tissues, and was associated with recurrence and survival of patients with ccRCC. However, the function of miR-125b in RCC remains unclear. Thus, the expression of miR-125b was detected with quantitative polymerase chain reaction (qPCR) in 24 paired RCC and adjacent normal tissues. The result of qPCR showed that miR-125b was upregulated in RCC tissues. Furthermore, the function of miR-125b in RCC (786-O and ACHN) cells was detected by transfecting miR-125 mimic or inhibitor to upregulate or downregulate miR-125b expression. Cell proliferation assays (MTT and Cell Counting Kit-8), cell mobility assays (cell scratch and Transwell assay) and a cell apoptotic assay (flow cytometry assay) were performed to assess the function of miR-125b on RCC cells. Results from the assays demonstrated that overexpression of miR-125b could promote cell migration and invasion, and reduce the cell apoptotic rate. It was also revealed that downregulation of miR-125b could reduce cell migration and invasion, and induce cell apoptosis. However, the results of the cell proliferation assay revealed that miR-125b had no significant effect on cell proliferation. Not only could miR-125b predict recurrence and survival of ccRCC; the present study revealed that miR-125b could regulate RCC cell migration, invasion and apoptosis. Additional studies are required to determine the mechanism of miR-125b in RCC cells and define the target genes of miR-125b in RCC.

Effects of a 28-day dietary co-exposure to melamine and cyanuric acid on the levels of serum microRNAs in male and female Fisher 344 rats

We showed previously that a 28-day combined dietary exposure to melamine and cyanuric acid (MEL&CYA) induced kidney lesions in NCTR Fisher 344 (F344) rats. Histopathological changes were significant in females dosed with ≥240 ppm MEL&CYA and in males dosed with ≥180 ppm MEL&CYA; however, the nephrotoxicity biomarkers blood urea nitrogen (BUN) and serum creatinine (SCr) were increased only by ≥240 ppm MEL&CYA. The serum miRNome has been reported to reflect toxicity of several organs, including the kidney. Here, we compared the dose-response of alterations in serum miRNAs to those of BUN, SCr, and kidney histopathology in rats co-exposed to MEL&CYA. The serum miRNome of male F344 rats dosed with 0, 180, or 240 ppm MEL&CYA was screened using quantitative real-time RT-PCR (qRT-PCR) and the levels of selected serum miRNAs were analyzed further in both sexes over the full dose range. The levels of several miRNAs were significantly reduced in rats treated with 240 ppm MEL&CYA versus control. In addition, miR-128-3p and miR-210-3p were decreased in males treated with 180pm MEL&CYA, a dose at which the levels of BUN and SCr were not yet affected by treatment. These data suggest that the serum miRNome is affected by nephrotoxic doses of MEL&CYA in male and female rats.

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.

High Expression of miR-532-5p, a Tumor Suppressor, Leads to Better Prognosis in Ovarian Cancer Both In Vivo and In Vitro

Ovarian cancer is the leading cause of death for gynecologic cancers, ranking fifth overall for cancer-related death among women. The identification of biomarkers and the elucidation of molecular mechanisms for improving treatment options have received extensive efforts in ovarian cancer research. miRNAs have high potential to act as both ovarian cancer biomarkers and as critical regulators of ovarian tumor behavior. We comprehensively analyzed global mRNA, miRNA expression, and survival data for ovarian cancer from The Cancer Genome Atlas (TCGA) to pinpoint miRNAs that play critical roles in ovarian cancer survival through their effect on mRNA expression. We performed miRNA overexpression and gene knockdown experiments to confirm mechanisms predicted in our bioinformatics approach. We established that overexpression of miR-532-5p in OVCAR-3 cells resulted in a significant decrease in cell viability over a 96-hour time period. In the TCGA ovarian cancer dataset, we found 67 genes whose expression levels were negatively correlated with miR-532-5p expression and correlated with patient survival, such as WNT9A, CSNK2A2, CHD4, and SH3PXD2A The potential miR-532-5p-regulated gene targets were found to be enriched in the Wnt pathway. Overexpression of miR-532-5p through miRNA mimic caused downregulation of CSNK2A2, CHD4, and SH3PXD2A in the OVCAR-3 cell line. We have discovered and validated the tumor-suppressing capabilities of miR-532-5p both in vivo through TCGA analysis and in vitro through ovarian cancer cell lines. Our work highlights the potential clinical importance of miR-532-5p expression in ovarian cancer patients. Mol Cancer Ther; 15(5); 1123-31. ©2016 AACR.

MiR-487a Promotes TGF-β1-induced EMT, the Migration and Invasion of Breast Cancer Cells by Directly Targeting MAGI2

Tumor metastasis is a complex and multistep process and its exact molecular mechanisms remain unclear. We attempted to find novel microRNAs (miRNAs) contributing to the migration and invasion of breast cancer cells. In this study, we found that the expression of miR-487a was higher in MDA-MB-231breast cancer cells with high metastasis ability than MCF-7 breast cancer cells with low metastasis ability and the treatment with transforming growth factor β1 (TGF-β1) significantly increased the expression of miR-487a in MCF-7 and MDA-MB-231 breast cancer cells. Subsequently, we found that the transfection of miR-487a inhibitor significantly decreased the expression of vimentin, a mesenchymal marker, while increased the expression of E-cadherin, an epithelial marker, in both MCF-7 cells and MDA-MB-231 cells. Also, the inactivation of miR-487a inhibited the migration and invasion of breast cancer cells. Furthermore, our findings demonstrated that miR-487a directly targeted the MAGI2 involved in the stability of PTEN. The down-regulation of miR-487a increased the expression of p-PTEN and PTEN, and reduced the expression of p-AKT in both cell lines. In addition, the results showed that NF-kappaB (p65) significantly increased the miR-487a promoter activity and expression, and TGF-β1 induced the increased miR-487a promoter activity via p65 in MCF-7 cells and MDA-MB-231 cells. Moreover, we further confirmed the expression of miR-487a was positively correlated with the lymph nodes metastasis and negatively correlated with the expression of MAGI2 in human breast cancer tissues. Overall, our results suggested that miR-487a could promote the TGF-β1-induced EMT, the migration and invasion of breast cancer cells by directly targeting MAGI2.

Expression of microRNA-452 via adenoviral vector inhibits non-small cell lung cancer cells proliferation and metastasis

The microRNA miR-452 has been shown to function as a tumor suppressor. However, the cellular mechanism and potential application of miR-452-mediated cancer suppression remain great unknown. This study aims to identify how miR-452 acts in regulating non-small cell lung cancer (NSCLC) proliferation and metastasis. Expression of miR-452 via adenoviral (Ad) vector inhibits the proliferation, invasion, and migration of NSCLC cells A549 or H460. Our data also shows that miR-452 down-regulates the expression of Bmi-1 as well as pro-survival or anti-apoptosis regulators Survivin, cIAP-1, and cIAP-2. By such gene interference, miR-452 modulates NSCLC cell epithelial-mesenchymal transition (EMT) and further disrupts their migration and invasion. Moreover, miR-452 blocks the activation of PI3K/AKT pathway, which is also required for EMT process. These data reveal that miR-452 treatment could be a novel target or strategy for NSCLC treatment.

Loss of miR-532-5p in vitro promotes cell proliferation and metastasis by influencing CXCL2 expression in HCC

MicroRNAs (miRNAs) have been widely reported, which play important roles in cancer development. CXCL2 acts as an oncogene, however, its regulation by miRNAs is not clear in hepatocellular carcinoma (HCC). In our research, it is aimed to study the role of CXCL2 in HCC and the regulation of its expression by miRNAs. Firstly, we found that CXCL2 was up-regulated in the blood of patients with HCC and cell lines compared with the normal controls. CXCL2 could enhance HCC cell proliferation and metastasis. miR-532-5p was predicted as a regulatory miRNA of CXCL2 in HCC, and negatively associated with CXCL2 in HCC samples. It was also verified that miR-532-5p inhibited cell proliferation and metastasis of HCC cells by inhibition CXCL2. Collectively, our findings suggested that miR-532-5p may function as a tumor suppressor in HCC by targeting CXCL2.

MicroRNA-22 functions as a tumor suppressor by targeting SIRT1 in renal cell carcinoma

Accumulating evidence demonstrates that microRNA-22 (miR-22) was deregulated in many types of cancers and was involved in various cellular processes related to carcinogenesis. However, the exact roles and mechanisms of miR-22 remain unknown in human renal cell carcinoma (RCC). Here, the relationship between miR-22 expression pattern and clinicopathological features of patients with EOC were determined by real-time quantitative RT-PCR (qRT-PCR). Furthermore, the role of miR-22 and possible molecular mechanisms in EOC were investigated by several in vitro approaches and in a nude mouse model. Results from qRT-PCR showed that miR-22 was significantly downregulated in RCC samples compared with corresponding non-cancerous tissues, which was significantly associated with tumor stage and lymph node metastasis. Functional study demonstrated that enforced overexpression of miR-22 in renal cancer cells inhibited proliferation, migration and invasion, and induced cell apoptosis in vitro, and suppressed tumor growth in vivo. In addition, SIRT1 was identified as a direct target of miR-22 by a luciferase reporter assay. Overexpression of miR-22 activated p53 and its downstream target p21 and PUMA, and the apoptosis markers cleaved CASP3 and PARP, and inhibited epithelial-mesenchymal transition (EMT). These findings showed that miR-22 functioned as tumor suppressor in RCC and blocked RCC growth and metastasis by directly targeting SIRT1 in RCC, indicating a potential novel therapeutic role in RCC treatment.