miR-181a-5p, an inducer of Wnt-signaling, facilitates cell proliferation in acute lymphoblastic leukemia

An in-silico approach to understand the potential role of Wnt inhibitory factor-1 (WIF-1) in the inhibition of the Wnt signalling pathway

WIF1 (Wnt inhibitory factor 1) is a potent tumour suppressor gene which is epigenetically silenced in numerous malignancies. The associations of WIF1 protein with the Wnt pathway molecules have not been fully explored, despite their involvement in the downregulation of several malignancies. In the present study, a computational approach encompassing the expression, gene ontology analysis and pathway analysis is employed to obtain an insight into the role of the WIF1 protein. Moreover, the interaction of the WIF1 domain with the Wnt pathway molecules was carried out to ascertain the tumour-suppressive role of the domain, along with the determination of their plausible interactions. Initially, the protein-protein interaction network analysis endowed us with the Wnt ligands (such as Wnt1, Wnt3a, Wnt4, Wnt5a, Wnt8a and Wnt9a), along with the Frizzled receptors (Fzd1 and Fzd2) and the low-density lipoprotein complex (Lrp5/6) as the foremost interactors of the protein. Further, the expression analysis of the aforementioned genes and proteins was determined using The Cancer Genome Atlas to comprehend the significance of the signalling molecules in the major cancer subtypes. Moreover, the associations of the aforementioned macromolecular entities with the WIF1 domain were explored using the molecular docking studies, whereas the dynamics and stability of the assemblage were investigated using 100 ns molecular dynamics simulations. Therefore, providing us insights into the plausible roles of WIF1 in inhibiting the Wnt pathways in various malignancies.Communicated by Ramaswamy H. Sarma.

Role of miR‑181a‑5p in cancer (Review)

MicroRNAs (miRNAs) are non‑coding RNAs (ncRNAs) that can post‑transcriptionally suppress targeted genes. Dysregulated miRNAs are associated with a variety of diseases. MiR‑181a‑5p is a conserved miRNA with the ability to regulate pathological processes, such as angiogenesis, inflammatory response and obesity. Numerous studies have demonstrated that miR‑181a‑5p exerts regulatory influence on cancer development and progression, acting as an oncomiR or tumor inhibitor in various cancer types by impacting multiple hallmarks of tumor. Generally, miR‑181a‑5p binds to target RNA sequences with partial complementarity, resulting in suppression of the targeted genes of miR‑181a‑5p. However, the precise role of miR‑181a‑5p in cancer remains incompletely understood. The present review aims to provide a comprehensive summary of recent research on miR‑181a‑5p, focusing on its involvement in different types of cancer and its potential as a diagnostic and prognostic biomarker, as well as its function in chemoresistance.

An integrated analysis of dysregulated SCD1 in human cancers and functional verification of miR-181a-5p/SCD1 axis in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC), one of the most lethal cancers, has become a global health issue. Stearoyl-coA desaturase 1 (SCD1) has been demonstrated to play a crucial role in human cancers. However, pan-cancer analysis has revealed little evidence to date. In the current study, we systematically inspected the expression patterns and potential clinical outcomes of SCD1 in multiple human cancers. SCD1 was dysregulated in several types of cancers, and its aberrant expression acted as a diagnostic biomarker, indicating that SCD1 may play a role in tumorigenesis. We used ESCC as an example to demonstrate that SCD1 was dramatically upregulated in tumor tissues of ESCC and was associated with clinicopathological characteristics in ESCC patients. Furthermore, Kaplan-Meier analysis showed that high SCD1 expression was correlated with poor progression-free survival (PFS) and disease-free survival (DFS) in ESCC patients. The protein-protein interaction (PPI) network and module analysis by PINA database and Gephi were performed to identify the hub targets. Meanwhile, the functional annotation analysis of these hubs was constructed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Functionally, the gain-of-function of SCD1 in ESCC cells promoted cell proliferation, migration, and invasion; in contrast, loss-of-function of SCD1 in ESCC cells had opposite effects. Bioinformatic, QPCR, Western blotting and luciferase assays indicated that SCD1 was a direct target of miR-181a-5p in ESCC cells. In addition, gain-of-function of miR-181a-5p in ESCC cells reduced the cell growth, migratory, and invasive abilities. Conversely, inhibition of miR-181a-5p expression by its inhibitor in ESCC cells had opposite biological effects. Importantly, reinforced SCD1 in miR-181a-5p mimic ESCC transfectants reversed miR-181a-5p mimic-prevented malignant phenotypes of ESCC cells. Taken together, these results indicate that SCD1 expression influences tumor progression in a variety of cancers, and the miR-181a-5p/SCD1 axis may be a potential therapeutic target for ESCC treatment.

Analysis of self-renewing and differentiation-related microRNAs and transcription factors in multilineage mouse hematopoietic stem/progenitor cells induced by 1,4-benzoquinone

Background

HSPCs are targets for benzene-induced hematotoxicity and leukemogenesis. However, benzene toxicity targeting microRNAs (miRNAs) and transcription factors (TF) that are involve in regulating self-renewing and differentiation of HSPCs comprising of different hematopoietic lineages remains poorly understood. In this study, the effect of a benzene metabolite, 1,4-benzoquinone (1,4-BQ) exposure, in HSPCs focusing on the self-renewing (miRNAs: miR-196b and miR-29a; TF: HoxB4, Bmi-1) and differentiation (miRNAs: miR-181a, TF: GATA3) pathways were investigated.

Methods

Freshly isolated mouse BM cells were initially exposed to 1,4-BQ at 1.25 to 5 µM for 24 h, followed by miRNAs and TF studies in BM cells. Then, the miRNAs expression was further evaluated in HSPCs of different lineages comprised of myeloid, erythroid and pre-B lymphoid progenitors following 7-14 days of colony forming unit (CFU) assay.

Results

Exposure to 1,4-BQ in BM cells significantly (p < 0.05) reduced the miR-196b (2.5 and 5 µM), miR-181a (1.25, 2.5 and 5 µM) and miR-29a (1.25 µM) along with upregulation of miR-29a at 2.5 µM. Meanwhile, 1,4-BQ exposure in HSPCs significantly increased the miR-196b expression level (p < 0.05) only in myeloid and pre-B lymphoid progenitors at 2.5 and 5 µM. Significant (p < 0.05) reduction in expression of miR-181a in myeloid (1.25 µM), erythroid (5 µM) progenitors along with miR-29a in myeloid (1.25 µM) and pre-B lymphoid (5 µM) progenitors were noted following exposure to 1,4-BQ. Meanwhile, increased expression of miR-181a was observed in pre-B lymphoid progenitor upon exposure to 1,4-BQ, but only at 5 µM. As for TF studies, expression of HoxB4 protein was significantly increased (p < 0.05) at all 1,4-BQ concentrations as compared to Bmi-1 and GATA3, which were significantly (p < 0.05) elevated starting at 2.5 µM of 1,4-BQ.

Conclusion

1,4-BQ induces aberration of miRNAs and transcription factors protein expression that are involved in regulating self-renewing and differentiation pathways of HSPCs. Moreover, epigenetic toxicity as evidenced from the miRNAs expression was found to be mediated by a lineage-driven mechanism. The role of cell lineage in governing the toxicity of 1,4-BQ in HSPCs lineages deserves further investigation.

A Comprehensive Overview of Recent Advances in Epigenetics in Pediatric Acute Lymphoblastic Leukemia

Recent years have brought a novel insight into our understanding of childhood acute lymphoblastic leukemia (ALL), along with several breakthrough treatment methods. However, multiple aspects of mechanisms behind this disease remain to be elucidated. Evidence suggests that leukemogenesis in ALL is widely influenced by epigenetic modifications. These changes include: DNA hypermethylation, histone modification and miRNA alteration. DNA hypermethylation in promoter regions, which leads to silencing of tumor suppressor genes, is a common epigenetic alteration in ALL. Histone modifications are mainly caused by an increased expression of histone deacetylases. A dysregulation of miRNA results in changes in the expression of their target genes. To date, several hundred genes were identified as suppressed by epigenetic mechanisms in ALL. What is promising is that epigenetic alterations in ALL may be used as potential biomarkers for classification of subtypes, predicting relapse and disease progression and assessing minimal residual disease. Furthermore, since epigenetic lesions are potentially reversible, an activation of epigenetically silenced genes with the use of hypomethylating agents or histone deacetylase inhibitors may be utilized as a therapeutic strategy for ALL. The following review summarizes our current knowledge about epigenetic modifications in ALL and describes potential uses of epigenetics in the clinical management of this disease.

MiRNA-181b-5p Modulates Cell Proliferation, Cell Cycle and Apoptosis by Targeting SSX2IP in Acute Lymphoblastic Leukemia

Objective:

Accumulating evidence indicates that miRNAs can negatively influence the expression of their downstream genes, thereby affecting the development of human cancers. The pathogenesis of acute lymphoblastic leukemia (ALL) is complex and more biomarkers and functional molecules need to be found. We attempted to reveal the specific mechanisms and functions of miRNA-181b-5p in ALL and investigated the effects of the miRNA-181b-5p/SSX2IP axis on ALL.

Materials and Methods:

Bioinformatics analyses were initially performed to screen out differentially expressed miRNAs in ALL and determine the research subject. qRT-PCR and western blotting were applied to evaluate the expression levels of target genes. Cell function experiments and mouse experiments were conducted to analyze the roles of the target genes in ALL.

Results:

miRNA-181b-5p was highly and differentially expressed in ALL and may target SSX2IP. The upregulation of miRNA-181b-5p and downregulation of SSX2IP were observed in ALL cells. miRNA-181b-5p could control multiple pathological processes of ALL, including cell proliferation, the cell cycle, and apoptosis, and miRNA-181b-5p could also facilitate tumor growth in vivo.

Conclusion:

miRNA-181b-5p promoted the malignant progression of ALL by downregulating SSX2IP. The miRNA-181b-5p/SSX2IP axis may be a promising target for intervention against the malignant behaviors of ALL.

The role of miRNAs as a big master regulator of signaling pathways involved in lymphoblastic leukemia

MicroRNAs (miRNAs) belong to small noncoding RNAs, which have long attracted researchers' attention because of their potency in acting either as oncogenes or tumor-suppressors in cancers. acute lymphocytic leukemia (ALL) and chronic lymphocytic leukemia (CLL) are two known types of leukemia with high mortality rates in adults and children. On a molecular basis, various signaling pathways are active in both types, making researchers consider the potential role of miRNAs in activating or suppressing these pathways to further hinder cancer development. In this review, we summarized the potential miRNAs, especially circulating ones, involved in essential signaling pathways in the ALL and CLL patients which serve as biomarkers and valuable targets in the treatment fields.

Exosomal miRNA-181a-5p from the cells of the hair follicle dermal papilla promotes the hair follicle growth and development via the Wnt/β-catenin signaling pathway

Exosomal miRNAs are verified critical biomarkers, which participate in several biological processes. The growth and development of the hair follicle (HF) are typically controlled by the exosomal miRNAs via cell-to-cell communication. This study identified a high expression of miR-181a-5p in the low-passage DPC-Exos (exosomes derived from dermal papilla cell), revealing the transportation patterns of the DPC-Exos-derived miR-181a-5p entering the HFSC (hair follicle stem cell). The exosomal miR-181a-5p activates the Wnt/β-catenin signaling pathway by targeting the Wnt inhibitor WIF1 and thereby regulates the proteins and genes related to HF growth and development. Moreover, the exosomal miR-181a-5p was found to suppress the HFSC apoptosis but promoted the HFSC proliferation. The in vitro culture of the HF organ revealed that the exosomal miR-181a-5p possesses a positive role in hair growth. Collectively, the exosomal miR-181a-5p affects the HF growth and development through the Wnt/β-catenin signaling pathway. The exosomal miR-181a-5p might, therefore, act as the novel biomarker and therapeutic target for treating hair-related diseases and wool production in mammals.

miRNA-seq and clinical evaluation in multiple myeloma: miR-181a overexpression predicts short-term disease progression and poor post-treatment outcome

BACKGROUND

Despite significant advances in multiple myeloma (MM) therapy, disease relapse and treatment resistance remain major obstacles in clinical management. Herein, we have studied the clinical utility of miRNAs in improving patients' risk-stratification and prognosis.

METHODS

miRNA-seq was performed in CD138+ plasma cells of MM, smoldering multiple myeloma (sMM) and monoclonal gammopathy of undetermined significance (MGUS) patients. The screening MM cohort consisted of 138 patients. miRNA levels of CD138+ plasma cells were quantified by RT-qPCR following 3'-end RNA polyadenylation. Disease progression and patients' death were used as clinical end-point events. Internal validation was conducted by bootstrap analysis. Clinical net benefit on disease prognosis was assessed by decision curve analysis. Kruykov et al. 2016 served as validation cohort (n = 151).

RESULTS

miRNA-seq highlighted miR-181a to be upregulated in MM vs. sMM/MGUS, and R-ISS III vs. I patients. Screening and validation cohorts confirmed the significantly higher risk for short-term progression and worse survival of the patients overexpressing miR-181a. Multivariate models integrating miR-181a with disease established markers led to superior risk-stratification and clinical benefit for MM prognosis.

CONCLUSIONS

CD138+ overexpression of miR-181a was strongly correlated with inferior disease outcome and contributed to superior prediction of MM patients early progression, supporting personalised prognosis and treatment decisions.

microRNA-181a-5p impedes the proliferation, migration, and invasion of retinoblastoma cells by targeting the NRAS proto-oncogene

OBJECTIVES

Accumulating research have reported that microRNAs (miRNAs) play important roles in Retinoblastoma (RB). Nonetheless, the function and underlying mechanism of miR-181a-5p in RB remain ambiguous.

METHODS

The relative expression levels of miR-181a-5p and NRAS mRNA were detected by quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). RB cell proliferation was measured using the Cell Counting Kit-8 (CCK-8) and 5'-Bromo-2'-deoxyuridine (BrdU) assays. Transwell assays and flow cytometry were performed to detect the migration, invasion, and apoptosis of RB cells. The interaction between miR-181a-5p and NRAS was explored using luciferase experiments, western blotting, and qRT-PCR.

RESULTS

miR-181a-5p expression was found to be decreased in RB tissues and cell lines, and its expression was correlated with unfavorable pathological features of the patients. In vitro experiments revealed that miR-181a-5p reduced RB cell proliferation, migration, and invasion while enhancing apoptosis. Further research confirmed that NRAS is a direct target of miR-181a-5p. miR-181a-5p inhibited NRAS expression at both the mRNA and protein levels. Co-transfection of pcDNA-NRAS or NRAS small interfering RNA (siRNA) reversed the effects of miR-181a-5p mimics or miR-181a-5p inhibitors on RB cells.

CONCLUSION

miR-181a-5p was significantly downregulated during the development of RB, and it suppressed the malignant behaviors of RB cells by targeting NRAS.

Extracellular vesicles carrying miRNA-181b-5p affects the malignant progression of acute lymphoblastic leukemia

Objective

To investigate how serum extracellular vesicles (EVs)-carried miRNA-181b-5p affected the proliferation, cell cycle and apoptosis of acute lymphoblastic leukemia (ALL) cells.

Methods

Differentially expressed miRNAs related to ALL were screened by bioinformatics analysis, and the localization of target miRNA was searched by its expression. qRT-PCR was adopted to confirm the expression of miRNA-181b-5p. Flow cytometry and fluorescence microscopy were applied to evaluate EVs internalization. MTT assay was employed to verify the proliferation of ALL cells. Cell cycle and apoptosis were analyzed by flow cytometry. Transwell assay was applied to evaluate migration and invasion abilities.

Results

High expression of miRNA-181b-5p was proved in ALL cell lines, and miRNA-181b-5p enriched in the exosomes and vesicles of blood cells. In the meantime, it was found that EVs carrying miRNA-181b-5p could be internalized by ALL cells and thus the expression of miRNA-181b-5p was up-regulated. Cell function assays showed that the proliferation, migration, invasion abilities of ALL cell lines were promoted in miRNA-181b-5p mimic group or the group co-culturing ALL-derived EVs and BALL-1 cell lines. The percentage of cells in G0/G1 phase was reduced and cell apoptosis was also inhibited.

Conclusion

miRNA-181b-5p carried by EVs in peripheral blood of ALL patients can enter ALL cells and thus promote the malignancy of ALL cells.

Identification of Potential Signatures and Their Functions for Acute Lymphoblastic Leukemia: A Study Based on the Cancer Genome Atlas

Objective

Acute lymphoblastic leukemia (ALL) is a malignant disease most commonly diagnosed in adolescents and young adults. This study aimed to explore potential signatures and their functions for ALL.

Methods

Differentially expressed mRNAs (DEmRNAs) and differentially expressed long non-coding RNAs (DElncRNAs) were identified for ALL from The Cancer Genome Atlas (TCGA) and normal control from Genotype-Tissue Expression (GTEx). DElncRNA-microRNA (miRNA) and miRNA-DEmRNA pairs were predicted using online databases. Then, a competing endogenous RNA (ceRNA) network was constructed. Functional enrichment analysis of DEmRNAs in the ceRNA network was performed. Protein-protein interaction (PPI) network was then constructed. Hub genes were identified. DElncRNAs in the ceRNA network were validated using Real-time qPCR.

Results

A total of 2,903 up- and 3,228 downregulated mRNAs and 469 up- and 286 downregulated lncRNAs were identified for ALL. A ceRNA network was constructed for ALL, consisting of 845 lncRNA-miRNA and 395 miRNA-mRNA pairs. These DEmRNAs in the ceRNA network were mainly enriched in ALL-related biological processes and pathways. Ten hub genes were identified, including SMAD3, SMAD7, SMAD5, ZFYVE9, FKBP1A, FZD6, FZD7, LRP6, WNT1, and SFRP1. According to Real-time qPCR, eight lncRNAs including ATP11A-AS1, ITPK1-AS1, ANO1-AS2, CRNDE, MALAT1, CACNA1C-IT3, PWRN1, and WT1-AS were significantly upregulated in ALL bone marrow samples compared to normal samples.

Conclusion

Our results showed the lncRNA expression profiles and constructed ceRNA network in ALL. Furthermore, eight lncRNAs including ATP11A-AS1, ITPK1-AS1, ANO1-AS2, CRNDE, MALAT1, CACNA1C-IT3, PWRN1, and WT1-AS were identified. These results could provide a novel insight into the study of ALL.

Long Non-Coding RNAs as Functional Codes for Oral Cancer: Translational Potential, Progress and Promises

Oral cancer is one of the leading malignant tumors worldwide. Despite the advent of multidisciplinary approaches, the overall prognosis of patients with oral cancer is poor, mainly due to late diagnosis. There is an urgent need to develop valid biomarkers for early detection and effective therapies. Long non-coding RNAs (lncRNAs) are recognized as key elements of gene regulation, with pivotal roles in various physiological and pathological processes, including cancer. Over the past few years, an exponentially growing number of lncRNAs have been identified and linked to tumorigenesis and prognosis outcomes in oral cancer, illustrating their emerging roles in oral cancer progression and the associated signaling pathways. Herein, we aim to summarize the most recent advances made concerning oral cancer-associated lncRNA, and their expression, involvement, and potential clinical impact, reported to date, with a specific focus on the lncRNA-mediated molecular regulation in oncogenic signaling cascades and oral malignant progression, while exploring their potential, and challenges, for clinical applications as biomarkers or therapeutic targets for oral cancer.

A Survival-Related Competitive Endogenous RNA Network of Prognostic lncRNAs, miRNAs, and mRNAs in Wilms Tumor

Wilms tumor (WT) commonly occurs in infants and children. We evaluated clinical factors and the expression of multiple RNAs in WT samples in the TARGET database. Eight long non-coding RNAs (lncRNAs; AC079310.1, MYCNOS, LINC00271, AL445228.3, Z84485.1, AC091180.5, AP002518.2, and AC007879.3), two microRNAs (miRNAs; hsa-mir-152 andhsa-mir-181a), and nine messenger RNAs (mRNAs; TCTEX1D4, RNF133, VRK1, CCNE1, HEY1, C10orf71, SPRY1, SPAG11A, and MAGEB18) were screened from differentially expressed RNAs and used to construct predictive survival models. These models showed good prognostic ability and were highly correlated with tumor stage and histological classification. Additionally, survival-related ceRNA network was constructed using 35 RNAs (15 lncRNAs, eight miRNAs, and 12 mRNAs). KEGG pathway analysis suggested the "Wnt signaling pathway" and "Cellular senescence" as the main pathways. In conclusion, we established a multinomial predictive survival model and a survival-related ceRNA network, which provide new potential biomarkers that may improve the prognosis and treatment of WT patients.

The miR-181a-SFRP4 Axis Regulates Wnt Activation to Drive Stemness and Platinum Resistance in Ovarian Cancer

Wnt signaling is a major driver of stemness and chemoresistance in ovarian cancer, yet the genetic drivers that stimulate its expression remain largely unknown. Unlike other cancers, mutations in the Wnt pathway are not reported in high-grade serous ovarian cancer (HGSOC). Hence, a key challenge that must be addressed to develop effective targeted therapies is to identify nonmutational drivers of Wnt activation. Using an miRNA sensor-based approach, we have identified miR-181a as a novel driver of Wnt/β-catenin signaling. miR-181a^high primary HGSOC cells exhibited increased Wnt/β-catenin signaling, which was associated with increased stem-cell frequency and platinum resistance. Consistent with these findings, inhibition of β-catenin decreased stem-like properties in miR-181a^high cell populations and downregulated miR-181a. The Wnt inhibitor SFRP4 was identified as a novel target of miR-181a. Overall, our results demonstrate that miR-181a is a nonmutational activator of Wnt signaling that drives stemness and chemoresistance in HGSOC, suggesting that the miR-181a-SFRP4 axis can be evaluated as a novel biomarker for β-catenin-targeted therapy in this disease. SIGNIFICANCE: These results demonstrate that miR-181a is an activator of Wnt signaling that drives stemness and chemoresistance in HGSOC and may be targeted therapeutically in recurrent disease.

Gene Methylation and Silencing of WIF1 Is a Frequent Genetic Abnormality in Mantle Cell Lymphoma

We have previously shown that the Wnt canonical pathway (WCP) is constitutively active in most cases of mantle cell lymphoma (MCL). Here, we aimed to elucidate the mechanisms underlying this biochemical deregulation. We hypothesized that gene methylation/silencing of WIF1 (Wnt inhibitory factor-1), a physiologic inhibitor of WCP, contributes to the deregulation of WCP and promotes cell growth in MCL. In support of this hypothesis, we found that the expression of WIF1 was detectable in none of the 4 MCL cell lines, and in only 2 of 5 tumors (40%) examined. Using methylation-specific PCR, we found evidence of gene methylation of WIF1 in 4 of 5 cell lines (80%) and in 24 of 29 (82%) tumors. The addition of the demethylation agent 5-aza-2′-deoxycytidine to Mino and JeKo-1, two WIF1-negative cell lines, restored the expression of WIF1 mRNA in these cells. Gene transfection of WIF1 into JeKo-1 and Mino cells significantly reduced cell growth, and this finding correlated with substantial downregulations of various proteins in WCP, such as β-catenin and pGSK-3β. In conclusion, our results support the concept that gene methylation/silencing of WIF1 is a frequent event in MCL, and this abnormality contributes to the aberrant activation of WCP. These results have provided further evidence that aberrant Wnt signaling is pathogenetically important in MCL and it may represent a potential therapeutic target.

Pinostilbene hydrate suppresses hepatic stellate cell activation via inhibition of miR-17-5p-mediated Wnt/β-catenin pathway

BACKGROUND

In the development of liver fibrosis, activated hepatic stellate cells (HSCs) contribute to the synthesis and deposition of extracellular matrix (ECM) proteins. HSC activation is considered as a central driver of liver fibrosis. Recently, microRNAs (miRNAs) have been reported to act as key regulators in HSC activation.

PURPOSE

Pinostilbene hydrate (PSH), a methylated derivative of resveratrol, has demonstrated anti-inflammatory, antioxidant and anti-tumour activities. However, the effects of PSH on HSC activation remain unclear.

METHODS

The effects of PSH on HSC activation were examined. Moreover, the roles of WNT inhibitory factor 1 (WIF1) and miR-17-5p in the effects of PSH on HSC activation were examined.

RESULTS

PSH induced a significant reduction in HSC proliferation. PSH also effectively inhibited HSC activation, with reduced α-SMA and collagen expression. Notably, it was found that Wnt/β-catenin signalling was involved in the effects of PSH on HSC activation. PSH resulted in Wnt/β-catenin signalling inactivation, with a reduction in TCF activity as well as β-catenin nuclear translocation. Further studies showed that PSH inhibited Wnt/β-catenin signalling via regulation of WIF1 and miR-17-5p. Reduced HSC activation caused by PSH could be restored by loss of WIF1 or miR-17-5p mimics. Luciferase reporter assays further confirmed that WIF1 was a target of miR-17-5p.

CONCLUSION

PSH has a significant protective effect against HSC activation. In addition, we demonstrate that PSH enhances WIF1 expression and inhibits Wnt/β-catenin signalling via miR-17-5p, contributing to the suppression of HSC activation.

Silencing of Exosomal miR-181a Reverses Pediatric Acute Lymphocytic Leukemia Cell Proliferation

Exosomes are cell-generated nano-vesicles found in most biological fluids. Major components of their cargo are lipids, proteins, RNA, DNA, and non-coding RNAs. The miRNAs carried within exosomes reveal real-time information regarding disease status in leukemia and other cancers, and therefore exosomes have been studied as novel biomarkers for cancer. We investigated the impact of exosomes on cell proliferation in pediatric acute lymphocytic leukemia (PALL) and its reversal by silencing of exo-miR-181a. We isolated exosomes from the serum of PALL patients (Exo-PALL) and conditioned medium of leukemic cell lines (Exo-CM). We found that Exo-PALL promotes cell proliferation in leukemic B cell lines by gene regulation. This exosome-induced cell proliferation is a precise event with the up-regulation of proliferative (PCNA, Ki-67) and pro-survival genes (MCL-1, and BCL2) and suppression of pro-apoptotic genes (BAD, BAX). Exo-PALL and Exo-CM both show over expression of miR-181a compared to healthy donor control exosomes (Exo-HD). Specific silencing of exosomal miR-181a using a miR-181a inhibitor confirms that miR-181a inhibitor treatment reverses Exo-PALL/Exo-CM-induced leukemic cell proliferation in vitro. Altogether, this study suggests that exosomal miR-181a inhibition can be a novel target for growth suppression in pediatric lymphatic leukemia.

Long Noncoding RNA SNHG7 Accelerates Proliferation, Migration and Invasion of Non-Small Cell Lung Cancer Cells by Suppressing miR-181a-5p Through AKT/mTOR Signaling Pathway

Purpose

Non-small cell lung cancer (NSCLC) is a typical epithelial lung cancer with high metastasis, incidence and mortality. In recent years, long noncoding RNA small nucleolar RNA host gene 7 (SNHG7) has been identified as significant regulator in different cancer types, including NSCLC. However, the underlying molecular mechanism of SNHG7 during NSCLC tumorigenesis and progression remains largely unclear.

Methods

SNHG7 and miR-181a-5p expression in NSCLC tumors and cells were detected by qRT-PCR. Cell viability, migration, invasion and apoptosis were evaluated by CCK-8, transwell and flow cytometry assay, respectively. A549 and NCI-H1299 xenograft mice model was constructed by subcutaneously injecting cells stably transfected with sh-SNHG7 and sh-NC. The interaction between SNHG7 and miR-181a-5p was validated by luciferase reporter system, RIP and RNA pull down assay. Protein expression of cleaved caspase 3, proliferating cell nuclear antigen (PCNA), AKT, p-AKT, mammalian target of rapamycin (mTOR) and p-mTOR was analyzed by Western blot.

Results

SNHG7 expression was up-regulated while miR-181a-5p expression was down-regulated in NSCLC tumors, especially those from patients at Phase III+IV, compared with normal tissues. However, SNHG7 depletion attenuated tumor growth in vitro and in vivo. Moreover, miR-181a-5p inhibitor abolished SNHG7 silencing induced inhibition on proliferation, migration and invasion in NSCLC. Subsequently, we found SNHG7 modulated cell progression by targeting miR-181a-5p and activating AKT/mTOR signaling pathway.

Conclusion

SNHG7 accelerates proliferation, migration and invasion of NSCLC by suppressing miR-181a-5p through AKT/mTOR signaling pathway, thus presenting desirable biomarkers for NSCLC therapy.

Long non-coding RNA CCAT2 promotes prostate cancer cell proliferation and invasion by regulating the Wnt/β-catenin signaling pathway

Long non-coding RNA colon cancer associated transcript 2 (CCAT2) is dysregulated in a number of different types of human cancer, and affects cancer progression via the Wnt/β-catenin signaling pathway. However, the roles of CCAT2 and the Wnt/β-catenin signaling pathway in prostate cancer (PCa) are not completely understood. The present study aimed to investigate the potential mechanism of CCAT2 in PCa. In the present study, the reverse transcription-quantitative PCR (RT-qPCR) results indicated that CCAT2 expression was significantly upregulated in PCa tissues, and DU145 and PC3 cell lines compared with normal prostate tissues and the epithelial RWPE-1 cell line, respectively. Functional assays indicated that CCAT2 downregulation inhibited DU145 and PC3 cell proliferation, cell cycle, migration and invasion. In addition, the luciferase reporter assay, RT-qPCR and western blotting results indicated that CCAT2 regulated transcription factor 7 like 2 (TCF7L2) expression by binding to microRNA-217. Further western blotting and TOPFlash assays indicated that CCAT2-knockdown inhibited the Wnt/β-catenin signaling pathway in DU145 and PC3 cell lines by inhibiting the expression of TCF7L2. However, CCAT2-knockdown-mediated effects were reversed by the Wnt/β-catenin signaling pathway activator lithium chloride (LiCl). Further cell experiments suggested that LiCl treatment reversed CCAT2-knockdown-mediated inhibition of PCa cell proliferation, cell cycle, epithelial-mesenchymal transition, migration and invasion. Overall, the results indicated that CCAT2 regulated PCa via the Wnt/β-catenin signaling pathway; therefore, CCAT2 may exhibit key role during the progression of PCa and may serve as a therapeutic target for the disease.

The multiple ways Wnt signaling contributes to acute leukemia pathogenesis

WNT proteins constitute a very conserved family of secreted glycoproteins that act as short-range ligands for signaling with critical roles in hematopoiesis, embryonic development, and tissue homeostasis. These proteins transduce signals via the canonical pathway, which is β-catenin-mediated and better-characterized, or via more diverse noncanonical pathways that are β-catenin independent and comprise the planar cell polarity (PCP) pathway and the WNT/Ca⁺⁺ pathways. Several proteins regulate Wnt signaling through a variety of sophisticated mechanisms. Disorders within the pathway can contribute to various human diseases, and the dysregulation of Wnt pathways by different molecular mechanisms is implicated in the pathogenesis of many types of cancer, including the hematological malignancies. The types of leukemia differ considerably and can be subdivided into chronic, myeloid or lymphocytic, and acute, myeloid or lymphocytic, leukemia, according to the differentiation stage of the predominant cells, the progenitor lineage, the diagnostic age strata, and the specific molecular drivers behind their development. Here, we review the role of Wnt signaling in normal hematopoiesis and discuss in detail the multiple ways canonical Wnt signaling can be dysregulated in acute leukemia, including alterations in gene expression and protein levels, epigenetic regulation, and mutations. Furthermore, we highlight the different impacts of these alterations, considering the distinct forms of the disease, and the therapeutic potential of targeting Wnt signaling.

High-Throughput MicroRNA Profiling of Vitreoretinal Lymphoma: Vitreous and Serum MicroRNA Profiles Distinct from Uveitis

Purpose: Vitreoretinal lymphoma (VRL) is a non-Hodgkin lymphoma of the diffuse large B cell type (DLBCL), which is an aggressive cancer causing central nervous system related mortality. The pathogenesis of VRL is largely unknown. The role of microRNAs (miRNAs) has recently acquired remarkable importance in the pathogenesis of many diseases including cancers. Furthermore, miRNAs have shown promise as diagnostic and prognostic markers of cancers. In this study, we aimed to identify differentially expressed miRNAs and pathways in the vitreous and serum of patients with VRL and to investigate the pathogenesis of the disease. Materials and Methods: Vitreous and serum samples were obtained from 14 patients with VRL and from controls comprising 40 patients with uveitis, 12 with macular hole, 14 with epiretinal membrane, 12 healthy individuals. The expression levels of 2565 miRNAs in serum and vitreous samples were analyzed. Results: Expression of the miRNAs correlated significantly with the extracellular matrix (ECM) ‒receptor interaction pathway in VRL. Analyses showed that miR-326 was a key driver of B-cell proliferation, and miR-6513-3p could discriminate VRL from uveitis. MiR-1236-3p correlated with vitreous interleukin (IL)-10 concentrations. Machine learning analysis identified miR-361-3p expression as a discriminator between VRL and uveitis. Conclusions: Our findings demonstrate that aberrant microRNA expression in VRL may affect the expression of genes in a variety of cancer-related pathways. The altered serum miRNAs may discriminate VRL from uveitis, and serum miR-6513-3p has the potential to serve as an auxiliary tool for the diagnosis of VRL.

Extracellular vesicle-mediated crosstalk between NPCE cells and TM cells result in modulation of Wnt signalling pathway and ECM remodelling

Primary open-angle glaucoma is a leading cause of irreversible blindness, often associated with increased intraocular pressure. Extracellular vesicles (EVs) carry a specific composition of proteins, lipids and nucleotides have been considered as essential mediators of cell-cell communication. Their potential impact for crosstalk between tissues responsible for aqueous humour production and out-flow is largely unknown. The study objective was to investigate the effects of EVs derived from non-pigmented ciliary epithelium (NPCE) primary cells on the expression of Wnt proteins in a human primary trabecular meshwork (TM) cells and define the mechanism underlying exosome-mediated regulation that signalling pathway. Consistent with the results in TM cell line, EVs released by both primary NPCE cells and NPCE cell line showed diminished pGSK3β phosphorylation and decreased cytosolic levels of β-catenin in primary TM cells. At the molecular level, we showed that NPCE exosome treatment downregulated the expression of positive GSKβ regulator-AKT protein but increased the levels of GSKβ negative regulator-PP2A protein in TM cells. NPCE exosome protein analysis revealed 584 miRNAs and 182 proteins involved in the regulation of TM cellular processes, including WNT/β-catenin signalling pathway, cell adhesion and extracellular matrix deposition. We found that negative modulator of Wnt signalling miR-29b was abundant in NPCE exosomal samples and treatment of TM cells with NPCE EVs significantly decreased COL3A1 expression. Suggesting that miR-29b can be responsible for decreased levels of WNT/β-catenin pathway. Overall, this study highlights a potential role of EVs derived from NPCE cells in modulating ECM proteins and TM canonical Wnt signalling.

GAS2 Promotes Cell Proliferation and Invasion and Suppresses Apoptosis in Pediatric T-Cell Acute Lymphoblastic Leukemia and Activates Wnt/β-Catenin Pathway

Purpose

This study aimed to investigate the effect of growth arrest specific 2 (GAS2) on T-cell acute lymphoblastic leukemia (T-ALL) and its potential molecular mechanism.

Methods

The GAS2 expression level was detected by qRT-RCR and Western blot in normal T lymphocytes and T-ALL cells Jurkat and CCRF-CEM. The proliferation and invasion of Jurkat and CCRF-CEM cells were detected by MTT and Transwell assay, respectively. Apoptosis and cell cycle were measured by flow cytometry. In addition, the chemotherapeutic sensitivity of Jurkat and CCRF-CEM cells was measured MTT assay and flow cytometry.

Results

GAS2 was highly expressed in Jurkat and CCRF-CEM cells. GAS2 could promote cell proliferation and invasion, and inhibit apoptosis of Jurkat and CCRF-CEM cells. GAS2 also promoted cell cycle changes from G0/G1 phase to S phase in Jurkat and CCRF-CEM cells. In addition, GAS2 could reduce the chemotherapeutic sensitivity of Jurkat and CCRF-CEM cells. GAS2 overexpression could promote the expression levels of ki67, proliferating cell nuclear antigen (PCNA), Bcl-2, c-myc, cyclin D1 and β-catenin, while GAS2 knockdown could inhibit their expression levels. Meanwhile, GAS2 overexpression could inhibit Bax expression. Moreover, Wnt/β-catenin pathway inhibitor XAV939 could inhibit the expressions of c-myc, cyclin D1 and β-catenin, but activator LiCl could promote their expression.

Conclusion

Our study demonstrated that GAS2 could promote cell proliferation and invasion, and induce cell cycle, as well as inhibit apoptosis and could activate the Wnt/β-catenin pathway in T-ALL cells.

Divergent effects of Wnt5b on IL-3- and GM-CSF-induced myeloid differentiation

The multiple specialized cell types of the hematopoietic system originate from differentiation of hematopoietic stem cells and progenitors (HSPC), which can generate both lymphoid and myeloid lineages. The myeloid lineage is preferentially maintained during ageing, but the mechanisms that contribute to this process are incompletely understood. Here, we studied the roles of Wnt5a and Wnt5b, ligands that have previously been linked to hematopoietic stem cell ageing and that are abundantly expressed by both hematopoietic progenitors and bone-marrow derived niche cells. Whereas Wnt5a had no major effects on primitive cell differentiation, Wnt5b had profound and divergent effects on cytokine-induced myeloid differentiation. Remarkably, while IL-3- mediated myeloid differentiation was largely repressed by Wnt5b, GM-CSF-induced myeloid differentiation was augmented. Furthermore, in the presence of IL-3, Wnt5b enhanced HSPC self-renewal, whereas in the presence ofGM-CSF, Wnt5b accelerated differentiation, leading to progenitor cell exhaustion. Our results highlight discrepancies between IL-3 and GM-CSF, and reveal novel effects of Wnt5b on the hematopoietic system.

miRNA deregulation in childhood acute lymphoblastic leukemia: a systematic review

Despite remarkable improvements in survival of childhood acute lymphoblastic leukemia (ALL), nonresponding or relapsing patients still represent one of the most frequent causes of death by disease in children. Accurate patient risk stratification based on genetic markers could increases survival rates. miRNAs can represent novel candidates with diagnostic, predictive and prognostic potential; however, many groups investigated their involvement with contradictory results. Aim: To clarify the role of miRNAs as biomarkers through a systematic review. Results: From a revision of 45 manuscripts, we found that miR-128 and miR-181 overexpression could represent markers for ALL diagnosis and underexpression of miR-708 and miR-99a could be markers for bad prognosis. Conclusion: These signatures could refine classification and risk stratification of patients and improve ALL outcome.

The role of microRNAs in acute lymphoblastic leukaemia: From biology to applications

MicroRNAs (miRNAs) that are characterized by small, noncoding RNA have an essential role in the pathogenesis of human diseases, including cancer. Furthermore, miRNAs, as a new paradigm of epigenetic regulators, play an important role in normal development and cellular function. This literature review summarizes the recurrent mechanism of gene regulation through miRNAs and, consequently, the impact of regulated genes on different cellular processes, including proliferation, metastasis, prognosis, and apoptosis. Additionally, what is important to note is that the expression of miRNAs in various cancer cells is different, and miRNAs have various target genes in various cancers. Accordingly, a proper understanding of gene regulation by miRNAs contributes to new perspectives in miRNA-based therapeutic strategies. SIGNIFICANCE OF THE STUDY: MiRNAs are considered as a crucial regulator of gene expression. The genes also play an important role in the expression of miRNAs; as a result, there is a relationship between them. In recent years, targeted therapy with miRNAs has been a significant challenge. Studying the mechanisms through which miRNAs regulate various cancer cell processes, including apoptosis, proliferation, and metastasis, is very critical in the treatment of cancer through miRNAs. Definitely, a proper understanding of the impacts of aberrant expression of miRNAs on cancer cell processes leads to new therapeutic strategies in the targeted therapy with miRNAs.

Expression and Role of MicroRNA-663b in Childhood Acute Lymphocytic Leukemia and its Mechanism

Recent studies have shown that microRNAs (miRNAs) play a key role in various malignant tumors. MiR-663b has been found to have important roles in several cancers, however, the role of miR-663b in T cell acute lymphocytic leukemia (T-ALL) remains unclear. Therefore, we speculated that miR-663b might also play a crucial role in the development and process of T-ALL. In the present study, we found that miR-663b was up-regulated in the blood of children with T-ALL and T-ALL cell lines. TargetScan and dual luciferase reporter assay results showed that CD99 was a direct target of miR-663b. In order to further study the biological function of miR-663b in the development of T-ALL and to clarify its potential molecular mechanism, we detected the changes in proliferation, apoptosis, migration, and invasion of T-ALL cell line Jurkat before and after miR-663b inhibitor transfection. We found that miR-663b inhibitor inhibited Jurkat cell proliferation and induced apoptosis. In addition, miR-663b inhibitor repressed Jurkat cell migration and invasion. All these effects of miR-663b inhibitor on Jurkat cells were eliminated by CD99-silencing. These results have provided a new theoretical basis and strategy for the diagnosis and treatment of T-ALL.

Circulating microRNAs as minimal residual disease biomarkers in childhood acute lymphoblastic leukemia

Background

Treatment stratification based on bone marrow minimal residual disease (MRD) at set time points has resulted in considerably improved survival in pediatric acute lymphoblastic leukemia (ALL). Treatment response is assessed using bone marrow samples. MicroRNAs (miRs) easily traffic among fluid spaces and are more stable than most other RNA classes. We examined the role of circulating miRs as putative less invasive MRD biomarkers.

Methods

In an exploratory experiment, expression of 46 preselected miRs was studied in platelet-free blood plasma samples of 15 de novo, 5 relapsed ALL patients and 10 controls by Custom TaqMan Array Advanced MicroRNA Card. Based on their high expression in ALL compared to controls, and on the reduction observed along the induction therapy, four miRs were selected for further analyses: miR-128-3p, -181a-5p, -181b-5p and 222-3p. Their expression was measured by qPCR at 4 time points in 27 de novo ALL patients treated in the ALL IC-BFM 2009 study.

Results

The expression of all 4 miRs significantly decreased over the first week of therapy (miR-128-3p: log₂ fold change − 2.86; adjusted p 3.6 × 10⁻⁷; miR-181b-5p: log₂ fold change − 1.75; adjusted p 1.48 × 10⁻²; miR-181a-5p: log₂ fold change -1.33; adjusted p 3.12 × 10⁻²; miR-222-3p: log₂ fold change − 1.25; adjusted p 1.66 × 10⁻²). However, no significant further reduction in miR expression was found after the 8th day of therapy. Measured drop in expression of 2 miRs at day 8 strongly correlated with day 15 bone marrow flow cytometry MRD results (miR-128-3p: Pearson’s r = 0.88, adjusted p = 2.71 × 10⁻⁴; miR-222-3p: r = 0.81, adjusted p = 2.99 × 10⁻³).

Conclusion

In conclusion, these circulating miRs might act as biomarkers of residual leukemia. MiR-128-3p and miR-222-3p in blood predict day 15 flow cytometry MRD results 7 days earlier. Although, their sensitivity falls behind that of bone marrow flow cytometry MRD at day 15.

Long non-coding RNA CCAT1 is a prognostic biomarker for the progression of oral squamous cell carcinoma via miR-181a-mediated Wnt/β-catenin signaling pathway

Oral squamous cell carcinoma (OSCC) ranks as the sixth most common carcinoma worldwide, and the third most common carcinoma in developing countries as well. Recently, the aberrant expression of lncRNA CCAT1 has been revealed to play an important role in the development of several cancers. However, its role in OSCC remains unknown. The expression levels of CCAT1 and miR-181a were determined in 15 paired primary OSCC tissues and their adjacent noncancerous tissues and cell lines with qPCR. shRNA against CCAT1 was employed to investigate the impact of CCAT1 on proliferation and metastasis. Then dual luciferase reporter and RIP assays were utilized to study the interaction between CCAT1 and miR-181a. Cells transfected with sh-CCAT1 or treated with miR-181a inhibitor were subjected to western blot to investigate the role of Wnt/β-catenin signaling in CCAT1-mediated proliferation and metastasis. Finally, the role of CCAT1 in OSCC was confirmed with tumor xenografts mice model. CCAT1 was upregulated in OSCC tissues and cell lines. Knockdown of CCAT1 inhibited the proliferation, migration and invasion of OSCC cells, while the cell apoptosis was enhanced. Luciferase and RIP assays revealed that miR-181a was a direct target of CCAT1. Inhibition of miR-181a partially reversed the efficacy of sh-CCAT1. Moreover, sh-CCAT1 inhibited OSCC tissues growth through inhibiting Wnt signaling in a miR-181a-dependent manner in vivo. lncRNA CCAT1 activated Wnt/β-catenin signaling via inhibiting miR-181a, resulting in the cell proliferation, migration and invasion of OSCC, suggesting that CCAT1 might serve as a potential target of OSCC treatment. Abbreviation: LncRNA: long non-coding RNA; OSCC: oral squamous cell carcinoma; 3' UTR: 3' untranslated region; ANOVA: one-way analysis of variance; CDK: cyclin-dependent kinase; ceRNA: competing endogenous RNA; FBS: fetal bovine serum; HGF: human gingival fibroblasts; MAPK: mitogen-activated protein kinase; miRNA: micro RNA; ncRNA: noncoding RNAs; PBS: phosphate-buffered saline; PI3K: phosphatidylinositol 3-kinase.

Molecular cloning of WIF1 and HMGA2 reveals ear-preferential expression while uncovering a missense mutation associated with porcine ear size in WIF1

Considerable diversity exists in porcine ear size, which is an important morphological feature of pig breeds. Previously, we localized four crucial candidate genes-high mobility group AT-hook 2 (HMGA2), LEM domain-containing 3 (LEMD3), methionine sulfoxide reductase B3 (MSRB3) and Wnt inhibitory factor 1 (WIF1)-on Sus Scrofa chromosome 5 affecting porcine ear size, then cloned LEMD3 and MSBR3. In this study, we performed rapid amplification of cDNA ends to obtain full-length cDNA sequences of 2338-bp WIF1 and 2998-bp HMGA2. Using quantitative real-time PCR, we revealed that WIF1 expression was highest in ear cartilage of 60-day-old pigs and that this is therefore a better candidate gene for ear size than HMGA2. We further screened coding sequence variants in both genes and identified only one missense mutation (WIF1:c.1167C>G) in a conserved epidermal growth factor-like domain from the mammalian WIF1 protein. The protein-altering mutation was significantly associated with ear size across the Large White × Minzhu hybrid and Beijing Black pig populations. When WIF1:c.1167C>G was included as fixed effect in the model to re-run a genome-wide association study in the Large White × Minzhu intercross population the P-value of the peak SNP on SSC5 from re-running the genome-wide association study dropped from 2.45E-12 to 7.33E-05. Taken together, the WIF1:c.1167C>G could be an important mutation associated with ear size. Our findings provide helpful information for further studies of the molecular mechanisms controlling porcine ear size.

MicroRNA in leukemia: Tumor suppressors and oncogenes with prognostic potential

Leukemia is known as a progressive malignant disease, which destroys the blood-forming organs and results in adverse effects on the proliferation and development of leukocytes and their precursors in the blood and bone marrow. There are four main classes of leukemia including acute leukemia, chronic leukemia, myelogenous leukemia, and lymphocytic leukemia. Given that a variety of internal and external factors could be associated with the initiation and progression of different types of leukemia. One of the important factors is epigenetic regulators such as microRNAs (miRNAs) and long noncoding RNAs (ncRNA). MiRNAs are short ncRNAs which act as tumor suppressor (i.e., miR-15, miR-16, let-7, and miR-127) or oncogene (i.e., miR-155, miR-17-92, miR-21, miR-125b, miR-93, miR-143-p3, miR-196b, and miR-223) in leukemia. It has been shown that deregulation of these molecules are associated with the initiation and progression of leukemia. Hence, miRNAs could be used as potential therapeutic candidates in the treatment of patients with leukemia. Moreover, increasing evidence revealed that miRNAs could be used as diagnostic and prognostic biomarkers in monitoring patients in early stages of disease or after received chemotherapy regimen. It seems that identification and development of new miRNAs could pave to the way to the development new therapeutic platforms for patients with leukemia. Here, we summarized various miRNAs as tumor suppressor and oncogene which could be introduced as therapeutic targets in treatment of leukemia.

Long non-coding RNA-CCAT2 promotes the occurrence of non-small cell lung cancer by regulating the Wnt/β-catenin signaling pathway

The present study aimed to investigate the biological function of colon cancer-associated transcript 2 (CCAT2) in the occurrence and progression of non-small cell lung carcinoma (NSCLC) and its potential use in the early diagnosis and molecular-targeted therapy of NSCLC. The tumor tissues, para-carcinoma tissues and associated clinical data of 36 patients with NSCLC were collected in order to detect the expression of CCAT2 and assess the impact of factors including histopathological type, Tumor-Node-Metastasis stage and lymph node metastasis on CCAT2 expression. The lung cancer NCI-H1975 cell line was transfected with a small interfering RNA (siRNA) plasmid to determine the effect of si-CCAT2 on NSCLC proliferation, invasion and metastasis. The effect of si-CCAT2 on the expression of nuclear and cytoplasmic β-catenin protein in the lung cancer NCI-H1975 cell line was detected using western blot analysis. The expression levels of CCAT2 in the tumor tissues of patients with NSCLC were significantly higher than those in the normal para-carcinoma tissues (t=8.580, P<0.01). Subsequent to CCAT2 silencing, the proliferation and invasive abilities of NCI-H1975 cells were significantly decreased compared with control cells (P<0.05). In the si-CCAT2 group, the level of nuclear and cytoplasmic β-catenin proteins was decreased, and the activity of the Wnt signaling pathway was significantly inhibited compared with the control cells (P<0.01), and a synergistic effect was exerted with the Wnt signaling inhibitor FH535. CCAT2 may therefore promote the occurrence of NSCLC by regulating the Wnt/β-catenin signaling pathway.

MicroRNAs as modulators of T cell functions in cancer

MicroRNAs (miRNAs) are short RNA molecules that regulate gene expression post-transcriptionally. They have emerged as important modulators of T lymphocyte biology, influencing cell activation, differentiation and proliferation in response to environmental signals. Here, we will discuss how miRNAs expressed by T cells can influence two key aspects of tumorigenesis, namely the direct, cell-intrinsic oncogenic transformation of T lymphocytes, as well as the indirect effects on tumor growth mediated by altered immune surveillance. We will specifically focus on three miRNAs that have been shown to regulate different aspects of T cell biology in both physiological and pathological conditions, namely miR-155, miR-146a and miR-181a. We aim at providing examples of the fundamental importance of miRNA-regulated networks in determining the fate of T lymphocytes during oncogenic transformation and in the control of tumor growth.

miRNA profiling identifies deregulated miRNAs associated with osteosarcoma development and time to metastasis in two large cohorts

Osteosarcoma (OS) is an aggressive bone tumor primarily affecting children and adolescents. The etiology of OS is not fully understood. Thus, there is a great need to obtain a better understanding of OS development and progression. Alterations in miRNA expression contribute to the required molecular alterations for neoplastic initiation and progression. This study is the first to investigate miRNA expression in OS in a large discovery and validation cohort comprising a total of 101 OS samples. We established the signature of altered miRNA expression in OS by profiling the expression level of 752 miRNAs in 23 OS samples using sensitive LNA-enhanced qPCR assays. The identified miRNA expression changes were correlated with gene expression in the same samples. Furthermore, miRNA expression changes were validated in a second independent cohort consisting of 78 OS samples. Analysis of 752 miRNAs in the discovery cohort led to the identification of 33 deregulated miRNAs in OS. Twenty-nine miRNAs were validated with statistical significance in the second cohort comprising 78 OS samples. miRNA/mRNA targets were determined, and 361 genes with an inverse expression of the target miRNA were identified. Both the miRNAs and the identified target genes were associated with multiple pathways related to cancer as well as bone cell biology, thereby correlating the deregulated miRNAs with OS tumorigenesis. An analysis of the prognostic value of the 29 miRNAs identified miR-221/miR-222 to be significantly associated with time to metastasis in both cohorts. This study contributes to a more profound understanding of OS tumorigenesis, by substantiating the importance of miRNA deregulation. We have identified and validated 29 deregulated miRNAs in the - to our knowledge - largest discovery and validation cohorts used so far for miRNA analyses in OS. Two of the miRNAs showed a promising potential as prognostic biomarkers for the aggressiveness of OS.

Post-transcriptional Regulation of Genes Related to Biological Behaviors of Gastric Cancer by Long Noncoding RNAs and MicroRNAs

Noncoding RNAs play critical roles in regulating protein-coding genes and comprise two major classes: long noncoding RNAs (lncRNAs) and microRNAs (miRNAs). LncRNAs regulate gene expression at transcriptional, post-transcriptional, and epigenetic levels via multiple action modes. LncRNAs can also function as endogenous competitive RNAs for miRNAs and indirectly regulate gene expression post-transcriptionally. By binding to the 3'-untranslated regions (3'-UTR) of target genes, miRNAs post-transcriptionally regulate gene expression. Herein, we conducted a review of post-transcriptional regulation by lncRNAs and miRNAs of genes associated with biological behaviors of gastric cancer.

Up-regulation of miR-181a in clear cell renal cell carcinoma is associated with lower KLF6 expression, enhanced cell proliferation, accelerated cell cycle transition, and diminished apoptosis

OBJECTIVES

Dysregulated expression of miR-181a accompanies tumorigenesis in many human cancers. However, in clear cell renal cell carcinoma (ccRCC), the role of miR-181a remains unclear. The aim of this study was to investigate biological functions of miR-181a and its expression levels in ccRCC tissues and cancer cell lines.

MATERIAL AND METHODS

Expression levels of miR-181a in samples of ccRCC tumors and adjacent nontumor tissues from 42 patients as well as in 786-O, 769-P, A498, and CAKI-1 ccRCC cell lines were determined by quantitative real-time polymerase chain reaction. Potential targets of miR-181a were predicted using bioinformatic approaches and then verified by using the luciferase reporter assay. The effects of miR-181a on cell proliferation, colony formation, cell cycle progression, and apoptosis were investigated in ccRCC cell lines transfected with specific miR-181a mimic and inhibitor.

RESULTS

We found that miR-181a expression was up-regulated in ccRCC tissues and cell lines. The expression level of miR-181a significantly correlated with the tumor size, tumor/node/metastasis staging, and Fuhrman grade. Luciferase assays showed that KLF6 was a target of miR-181a. KLF6 expression was inversely correlated with the level of miR-181a. Overexpression of miR-181a led to reduced KLF6 mRNA and protein levels, whereas mutations of the potential miR-181a binding sites in the KLF6 gene abrogated this inhibitory effect. Furthermore, overexpression of miR-181a promoted proliferation and G1/S cell cycle transition, as well as inhibited apoptosis by down-regulating KLF6 in ccRCC cells.

CONCLUSIONS

miR-181a is up-regulated in ccRCC and may act as a tumor promoting factor by targeting KLF6 expression. Manipulating miR-181a may provide a beneficial effect in the treatment of ccRCC.