miR-125a regulates cell cycle, proliferation, and apoptosis by targeting the ErbB pathway in acute myeloid leukemia

Correlation analysis of bone marrow microvessel density and miRNA expression on drug resistance in patients with chronic myelogenous leukemia after tyrosine kinase inhibitor treatment

OBJECTIVE

This study analyzed the relationship between bone marrow microvessel density (MVD) and the expression of four miRNAs with chronic myelogenous leukemia (CML) resistance after tyrosine kinase inhibitor (TKI) treatment.

METHODS

234 CML patients were divided into resistance and non-resistance groups in terms of the results of the 5-year follow-up. Patients were divided into the Optimum response group and the Warning/Failure group based on TKI response. MVD was determined by immunohistochemistry, and the expression levels of four miRNAs (miR-106a, miR-155, miR-146a, and miR-340) in bone marrow biopsy specimens were examined by qPCR. We evaluated the association of MVD with four miRNAs and them predictive value for CML resistance after TKI treatment.

RESULTS

The MVD and the levels of miR-106a, miR-155, and miR-146a were significantly higher while the miR-340 level was lower in the resistance group than the non-resistance group. Besides, MVD had a significant correlation with the levels of miR-340 and miR-155. According to the results of survival analysis, MVD as well as miR-340 and miR-155 levels were observably correlated with 5-year survival of patients without TKI resistance. The results of the ROC curve indicated that the MVD, miR-106a, miR-340, and miR-155 had good predictive accuracy for CML resistance after TKI treatment. As for the results of multivariate analysis, disease stage, risk level (high risk), high MVD, low miR-340 expression, and high miR-155 expression were all independent risk factors for CML resistance.

CONCLUSION

MVD and the expression of miR-340 and miR-155 are closely associated with CML resistance after TKI treatment.

Circ_0058058 Knockdown Inhibits Acute Myeloid Leukemia Progression by Sponging miR-4319 to Regulate EIF5A2 Expression

Background: Acute myeloid leukemia (AML) is the most common acute leukemia in adults. Circular RNAs (circRNAs) participate in the deterioration of many hominine cancers, including AML. In this study, the authors investigated the role and potential mechanism of circ_0058058 in AML progression. Methods: The expression of circ_0058058, microRNA-4319 (miR-4319), and eukaryotic initiation factor 5A2 (EIF5A2) was determined by quantitative real-time polymerase chain reaction. Cell proliferation, apoptosis, migration, and invasion were evaluated by cell counting kit-8 (CCK-8), cell colony formation, flow cytometry, and transwell assay, respectively. Levels of the relative proteins were detected by Western blot. The connection among circ_0058058, miR-4319, and EIF5A2 was verified by dual-luciferase reporter assay. Results: Circ_0058058 and EIF5A2 were enhanced, whereas miR-4319 was declined in AML. Circ_0058058 knockdown inhibited cell proliferation, migration, and invasion, and facilitated cell apoptosis by targeting miR-4319 in AML cells. Moreover, as a target of miR-4319, EIF5A2 overexpression overturned the inhibitory effects of miR-4319 upregulation on AML progression. Besides, circ_0058058 sponged miR-4319 to upregulate EIF5A2 expression in AML cells. Conclusion: Circ_0058058 knockdown inhibited cell proliferation, migration, and invasion, but accelerated cell apoptosis by reducing EIF5A2 expression by targeting miR-4319, suggesting that circ_0058058 could be a therapeutic target for the treatment of AML.

Evaluation of MicroRNA as Minimal Residual Disease in Leukemia: Diagnostic and Prognostic Approach: A Review

Various factors are effective in the development of minimal residual disease (MRD), one of which is MicroRNAs (miRNAs). miRNAs and their dysfunction in gene expression have influential role in the pathogenesis of leukemia. Nowadays, treatments that lead to the suppression or replacement of miRNAs have been developed. Focusing on the role of miRNAs in managing the treatment of leukemia, in this review article we have investigated the miRNAs and signaling pathways involved in the process of apoptosis and cell proliferation, as well as miRNAs with oncogenic function in malignant leukemia cells. Among the studied miRNAs, miR-99a, and miR-181a play an essential role in apoptosis, proliferation and oncogenesis via AKT, MAPK, RAS, and mTOR signaling pathways. miR-223 and miR-125a affect apoptosis and oncogenesis via Wnt/B-catenin, PTEN/PI3K, and STAT5/AKT/ERK/Src signaling pathways. miR-100 also affects both apoptosis and oncogenesis; it acts via IGF1 and mTOR signaling pathways.

Targeting Signaling Pathway by Curcumin in Osteosarcoma

The most prevalent primary bone malignancy among children and adolescents is osteosarcoma. The high mortality rate of osteosarcoma is due to lung metastasis. Despite the development of multi-agent chemotherapy and surgical resection, patients with osteosarcoma have a high metastasis rate and poor prognosis. Thus, it is necessary to identify novel therapeutic agents to improve the 5-year survival rate of these patients. Curcumin, a phytochemical compound derived from Curcuma longa, has been employed in treating several types of cancers through various mechanisms. Also, in vitro studies have demonstrated that curcumin could inhibit cell proliferation and induce apoptosis in osteosarcoma cells. Development in identifying signaling pathways involved in the pathogenesis of osteosarcoma has provided insight into finding new therapeutic targets for the treatment of this cancer. Targeting MAPK/ERK, PI3k/AKT, Wnt/β-catenin, Notch, and MircoRNA by curcumin has been evaluated to improve outcomes in patients with osteosarcoma. Although curcumin is a potent anti-cancer compound, it has rarely been studied in clinical settings due to its congenital properties such as hydrophobicity and poor bioavailability. In this review, we recapitulate and describe the effect of curcumin in regulating signaling pathways involved in osteosarcoma.

Expression profiling of N6-methyladenosine modified circRNAs in acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults, associated with poor prognosis and easy relapse of disease. Circular RNAs (circRNAs) were detected to be m⁶A modified and the role of m⁶A circRNAs has been reported in other diseases including cancers, however, their role has not been elucidated in AML yet. In the present study, we aimed to investigate the expression profiling of m⁶A circRNAs in AML. We performed m⁶A circRNAs microarray analysis to identify differentially expressed m⁶A circRNAs in bone marrow samples from AML patients and healthy individuals (control). Furthermore, bioinformatics analysis predicted the potential functions and relevant pathways that may be associated with the m⁶A circRNAs. The circRNA m⁶A methylation levels were found to be positively associated with the circRNAs expression, suggesting circRNA m⁶A modification could contribute to circRNA regulation in AML. Further analysis demonstrated that circRNA m⁶A modification might influence the circRNA-miRNA-mRNA co-expression network that may contribute to the circRNA regulatory network in AML. Our findings provide evidence of the differential expression profile of m⁶A circRNAs in AML, and circRNA m⁶A modification may contribute to circRNA regulatory function in AML.

Rs12976445 polymorphism is associated with the risk of post-SAH re-bleeding by modulating the expression of microRNA-125 and ET-1

This study aimed to study the association between rs12976445 polymorphism and the incidence of IA re-bleeding. Genotype and allele frequency analysis was performed to study the association between rs12976445 polymorphism and the risk of IA re-bleeding. Western blot, ELISA and real-time RT-PCR were conducted to measure the relative expression of miR-125a, ET1 mRNA and ET1 protein. Computational analysis and luciferase assays were utilized to investigate the association between the expression of miR-125a and ET1 mRNA. No significant differences were observed between IA patients with or without symptoms of re-bleeding. Subsequent analyses indicated that the T allele was significantly associated with the reduced risk of IA re-bleeding. In patients carrying the CC genotype, miR-125a level was up-regulated while ET1 mRNA/protein levels were reduced compared with those in patients carrying the CT or TT genotype. And ET1 mRNA was identified as a virtual target gene of miR-125a with a potential miR-125a binding site located on its 3’UTR. Accordingly, the ET mRNA/protein levels could be suppressed by the transfection of miR-125a precursors, but the transfection of ET1 siRNA exhibited no effect on the expression of miR-125a. Therefore, an increased level of miR-125a can lead to the increased risk of IA re-bleeding. Since miR-125a level is higher in CC-genotyped patients, it can be concluded that the presence of T allele in the rs12976445 polymorphism is associated with a lower risk of IA re-bleeding, and miR-125a may be used as a novel diagnostic and therapeutic target for IA rupture.

Regulatory noncoding RNAs: potential biomarkers and therapeutic targets in acute myeloid leukemia

The noncoding RNAs (ncRNA) comprise a substantial segment of the human transcriptome and have emerged as key elements of cellular homeostasis and disease pathogenesis. Dysregulation of these ncRNAs by alterations in the primary RNA motifs and/or aberrant expression levels is relevant in various diseases, especially cancer. The recent research advances indicate that ncRNAs regulate vital oncogenic processes, including hematopoietic cell differentiation, proliferation, apoptosis, migration, and angiogenesis. The ever-expanding role of ncRNAs in cancer progression and metastasis has sparked interest as potential diagnostic and prognostic biomarkers in acute myeloid leukemia. Moreover, advances in antisense oligonucleotide technologies and pharmacologic discoveries of small molecule inhibitors in targeting RNA structures and RNA-protein complexes have opened newer avenues that may help develop the next generation anti-cancer therapeutics. In this review, we have discussed the role of ncRNA in acute myeloid leukemia and their utility as potential biomarkers and therapeutic targets.

MiR-125a-3p and MiR-320b Differentially Expressed in Patients with Chronic Myeloid Leukemia Treated with Allogeneic Hematopoietic Stem Cell Transplantation and Imatinib Mesylate

Chronic myeloid leukemia (CML), a hematopoietic neoplasm arising from the fusion of BCR (breakpoint cluster region) gene on chromosome 22 to the ABL (Abelson leukemia virus) gene on chromosome 9 (BCR-ABL1 oncogene), originates from a small population of leukemic stem cells with extensive capacity for self-renewal and an inflammatory microenvironment. Currently, CML treatment is based on tyrosine kinase inhibitors (TKIs). However, allogeneic hematopoietic stem cell transplantation (HSCT-allo) is currently the only effective treatment of CML. The difficulty of finding a compatible donor and high rates of morbidity and mortality limit transplantation treatment. Despite the safety and efficacy of TKIs, patients can develop resistance. Thus, microRNAs (miRNAs) play a prominent role as biomarkers and post-transcriptional regulators of gene expression. The aim of this study was to analyze the miRNA profile in CML patients who achieved cytogenetic remission after treatment with both HSCT-allo and TKI. Expression analyses of the 758 miRNAs were performed using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Bioinformatics tools were used for data analysis. We detected miRNA profiles using their possible target genes and target pathways. MiR-125a-3p stood out among the downregulated miRNAs, showing an interaction network with 52 target genes. MiR-320b was the only upregulated miRNA, with an interaction network of 26 genes. The results are expected to aid future studies of miRNAs, residual leukemic cells, and prognosis in CML.

High expression of long noncoding RNA NORAD is associated with poor clinical outcomes in non-M3 acute myeloid leukemia patients

OBJECTIVE/BACKGROUND

Dysregulation of long noncoding RNA NORAD has been identified in human solid tumors. However, the expression profile of NORAD and its clinical implications in acute myeloid leukemia (AML) is unclear. The current study aimed to explore the NORAD expression status and its clinical significance in non-M3 AML patients.

METHODS

NORAD expression was evaluated in 60 de novo non-M3 AML patients and 49 healthy individuals using quantitative reverse transcription-polymerase chain reaction method. The correlation between NORAD transcription levels and clinicopathologic characteristics was statistically studied.

RESULTS

Compared with the healthy controls, NORAD was consistently higher in non-M3 AML patients (p = .01). Furthermore, initial NORAD upregulation occurred more frequently in patients with unfavorable cytogenetic risk (p = .02). The non-M3 AML patients were divided into NORAD high-expressing (NORADhigh) and NORAD low-expressing (NORADlow) groups based on the median NORAD expression level. Univariate analyses revealed that patients with high expression levels of NORAD had relatively poor overall survival (p = .03) and relapse-free survival (RFS) (p = .01). Additionally, multivariate analysis highlighted that NORAD upregulation was an independent risk factor for RFS.

CONCLUSION

Our observations indicate the fact that high expression of NORAD could be an unfavorable risk factor in non-M3 AML patients, and NORAD might be a novel therapeutic candidate for future treatments targeting AML.

EGFR inhibitors regulate Ca2+ concentration and apoptosis after PM2.5 exposure based on a lung-mimic microfluidic system

Air pollution has side effects on human health. Epidemiology studies indicate a positive association between ambient fine particle (PM_2.5, or particles less than 2.5 μm in diameter) concentration and lung cancer. However, how fine particles affect lung cancer at the molecular level and related therapeutic methods to address these diseases are unclear. Here, the multi-omics analysis (DNA methylation and transcriptomic) was used to detect human bronchial epithelial cells (HBE), that were exposed to PM_2.5 using a quantified, small, portable, and organ-level air-liquid interface microfluidic system that mimics lung functions. The results indicate that 36,838 differentially methylated genes were detected. Of these 33,796 genes were hypomethylated (beta < 0), and 2862 genes were hypermethylated (beta > 0). RNA-Seq analysis demonstrated that 19,489 genes were upregulated (log₂FC > 0), and 16,659 were downregulated. Furthermore, the calcium and apoptosis pathways were activated according to multi-omics analysis. The change in EGFR gene expression after PM_2.5 exposure was the result of alterations of the cellular DNA methylome in the promoter. Inhibition or down-regulation of EGFR could result in the regulation of the downstream intracellular Ca²⁺ concentration and apoptosis via the EGFR/PLCγ and EGFR/STAT/Bcl-XL pathways after PM_2.5 exposure. EGFR inhibitors decrease the Ca²⁺ concentration of cells, thereby strengthening the effects of fine particles on apoptosis. In short, the Ca²⁺ concentration and the apoptosis of cells can be regulated via EGFR related pathway after PM_2.5 exposure. The EGFR may be a potentially promising therapeutic target for the treatment of air pollution-induced lung cancer through regulation of the intracellular Ca²⁺ concentration and apoptosis.

A Facile Total Synthesis of Mubritinib

A five-step, practical, and concise total synthesis of mubritinib is described. The synthesis utilized Friedel–Crafts acylation, click reaction, reduction, and demethylation for the construction of the triazole ring system as key steps. Another important feature of this synthesis is the Bredereck oxazole synthesis. The main advantages of this process are the improved yield and decreased number of reaction steps, which paves the way for the industrial-scale synthesis of mubritinib.

MicroRNAs Associated With a Good Prognosis of Acute Myeloid Leukemia and Their Effect on Macrophage Polarization

Acute myeloid leukemia (AML) is an aggressive myeloid malignancy with poor outcomes despite very intensive therapeutic approaches. For the majority of patients which are unfit and treated less intensively, the prognosis is even worse. There has been unspectacular progress in outcome improvement over the last decades and the development of new approaches is of tremendous interest. The tumor microenvironment is credited with an important role in supporting cancer growth, including leukemogenesis. Macrophages are part of the tumor microenvironment and their contribution in this setting is increasingly being deciphered, these cells being credited with a tumor supporting role. Data on macrophage role and polarization in leukemia is scarce. MicroRNAs (miRNAs) have a role in the post-transcriptional regulation of gene expression, by impending translation and promoting degradation of messenger RNAs. They are important modulators of cellular pathways, playing major roles in normal hematopoietic differentiation. miRNA expression is significantly correlated with the prognosis of hematopoietic malignancies, including AML. Oncogenic miRNAs correlate with poor prognosis, while tumor suppressor miRNAs, which inhibit the expression of proto-oncogenes, are correlated with a favorable prognosis. miRNAs are proposed as biomarkers for diagnosis and prognosis and are regarded as therapeutic approaches in many cancers, including AML. miRNAs with epigenetic or modulatory activity, as well as with synergistic activity with chemotherapeutic agents, proved to be promising therapeutic targets in experimental, pre-clinical approaches. The clinical availability of emerging compounds with mimicking or suppressor activity provides the opportunity for future therapeutic targeting of miRNAs. The present paper is focusing on miRNAs which, according to current knowledge, favorably impact on AML outcomes, being regarded as tumor suppressors, and reviews their role in macrophage polarization. We are focusing on miRNA expression in the setting of AML, but data on correlations between miRNA expression and macrophage polarization is mostly coming from studies involving normal tissue.

Micro-RNA-125a mediates the effects of hypomethylating agents in chronic myelomonocytic leukemia

BACKGROUND

Chronic myelomonocytic leukemia (CMML) is an aggressive hematopoietic malignancy that arises from hematopoietic stem and progenitor cells (HSPCs). Patients with CMML are frequently treated with epigenetic therapeutic approaches, in particular the hypomethylating agents (HMAs), azacitidine (Aza) and decitabine (Dec). Although HMAs are believed to mediate their efficacy via re-expression of hypermethylated tumor suppressors, knowledge about relevant HMA targets is scarce. As silencing of tumor-suppressive micro-RNAs (miRs) by promoter hypermethylation is a crucial step in malignant transformation, we asked for a role of miRs in HMA efficacy in CMML.

RESULTS

Initially, we performed genome-wide miR-expression profiling in a Kras^G12D-induced CMML mouse model. Selected candidates with prominently decreased expression were validated by qPCR in CMML mice and human CMML patients. These experiments revealed the consistent decrease in miR-125a, a miR with previously described tumor-suppressive function in myeloid neoplasias. Furthermore, we show that miR-125a downregulation is caused by hypermethylation of its upstream region and can be reversed by HMA treatment. By employing both lentiviral and CRISPR/Cas9-based miR-125a modification, we demonstrate that HMA-induced miR-125a upregulation indeed contributes to mediating the anti-leukemic effects of these drugs. These data were validated in a clinical context, as miR-125a expression increased after HMA treatment in CMML patients, a phenomenon that was particularly pronounced in cases showing clinical response to these drugs.

CONCLUSIONS

Taken together, we report decreased expression of miR-125a in CMML and delineate its relevance as mediator of HMA efficacy within this neoplasia.

Silencing of long noncoding RNA TUG1 inhibits viability and promotes apoptosis of acute myeloid leukemia cells by targeting microRNA-221-3p/KIT axis

OBJECTIVE: Acute myeloid leukemia (AML) is a hematological malignancy. This study was attempted to uncover the effects of long noncoding RNA taurine-upregulated gene1 (TUG1) on the viability and apoptosis of AML cells. METHODS: QRT-PCR was implemented to examine the expression of TUG1, miR-221-3p and KIT in AML. The correlation between TUG1 and clinicopathological features of AML patients was evaluated. The effect of TUG1 on AML cells were studied by RNA interference approach. AML cells were transfected with miR-221-3p mimic and miR-221-3p inhibitor, respectively. Then the viability and apoptosis of AML cells were examined by MTT and flow cytometry assay, respectively. Additionally, dual-luciferase reporter assay was used to confirm the interactions among TUG1, miR-221-3p and KIT. Western blot was applied to analyze protein expression of KIT. RESULTS: The expression of TUG1 and KIT was up-regulated in AML, but miR-221-3p was down-regulated. TUG1 expression had obviously correlation with World Health Organization (WHO) grade in AML patients. The functional experiment stated that TUG1 silencing suppressed the viability and accelerated the apoptosis of AML cells. Moreover, the mechanical experiment demonstrated that TUG1 and KIT were both targeted by miR-221-3p with the complementary binding sites at 3’UTR. Up-regulation of miR-221-3p inhibited the protein expression of KIT. Furthermore, in the feedback experiment, miR-221-3p inhibition or KIT overexpression reversed the repression of tumor behavior induced by TUG1 silencing. CONCLUSIONS: TUG1 silencing retarded viability and promoted apoptosis of AML cells via regulating miR-221-3p/KIT axis, providing a potential therapeutic target for AML.

Role of microRNA dysregulation in childhood acute leukemias: Diagnostics, monitoring and therapeutics: A comprehensive review

MicroRNAs (miRNAs) are short noncoding RNAs that regulate the expression of genes by sequence-specific binding to mRNA to either promote or block its translation; they can also act as tumor suppressors (e.g., let-7b, miR-29a, miR-99, mir-100, miR-155, and miR-181) and/or oncogenes (e.g., miR-29a, miR-125b, miR-143-p3, mir-155, miR-181, miR-183, miR-196b, and miR-223) in childhood acute leukemia (AL). Differentially expressed miRNAs are important factors associated with the initiation and progression of AL. As shown in many studies, they can be used as noninvasive diagnostic and prognostic biomarkers, which are useful in monitoring early stages of AL development or during therapy (e.g., miR-125b, miR-146b, miR-181c, and miR-4786), accurate classification of different cellular or molecular AL subgroups (e.g., let-7b, miR-98, miR-100, miR-128b, and miR-223), and identification and development of new therapeutic agents (e.g., mir-10, miR-125b, miR-203, miR-210, miR-335). Specific miRNA patterns have also been described for commonly used AL therapy drugs (e.g., miR-125b and miR-223 for doxorubicin, miR-335 and miR-1208 for prednisolone, and miR-203 for imatinib), uncovering miRNAs that are associated with treatment response. In the current review, the role of miRNAs in the development, progression, and therapy monitoring of pediatric ALs will be presented and discussed.

Exosomes-mediated Transfer of miR-125a/b in Cell-to-cell Communication: A Novel Mechanism of Genetic Exchange in the Intestinal Microenvironment

Glucagon-like peptide-2 (GLP-2), a key factor in intestinal rehabilitation therapy of short bowel syndrome (SBS), may require cell-to-cell communication to exert its biological functions. However, understanding of the mechanism remains elusive. Here, we report participation of exosomal miR-125a/b in GLP-2 mediated intestinal epithelial cells-myofibroblasts cross-talk in intestinal microenvironment.

Methods: The effects of GLP-2 on the proliferation and apoptosis of intestinal epithelial cells in SBS rat models were evaluated. Exosomes were extracted from residual jejunum tissue of GLP-2 or vehicle treated SBS rats using ultracentrifugation method, and identified by nanoparticle trafficking analysis (NTA), transmission electron microscopy and western blotting. miRNA sequencing combined with qRT-PCR validation were used to identify differentially expressed miRNAs. miRNAs, which might be involved in proliferation and apoptosis of intestinal epithelial cells, were screened and further verified by miRNA functional experiments. Moreover, the proliferation-promoting and anti-apoptosis effects of GLP-2 on intestinal myofibroblasts, which expressing GLP-2 receptor, and whether GLP-2 could influence the content of miRNAs in the derived exosomes were studied. The downstream pathways were explored by miRNA function recovery experiment, luciferase reporter assay, pull down experiment, knockdown and overexpression of target gene and other experiments based on the bioinformatics prediction of miRNA target gene.

Results: GLP-2 significantly promoted intestinal growth, facilitated the proliferation of intestinal crypt epithelial cells and inhibited the apoptosis of intestinal villi epithelial cells in type II SBS rats. GLP-2 significantly down-regulated exosomal miR-125a/b both in residual jejunums derived exosomes and in exosomes secreted by GLP-2R positive cells. Exosomal miR-125a/b was responsible for GLP-2 mediated intestinal epithelial cells proliferation promotion and apoptosis attenuation. miR-125a/b inhibited the proliferation and promotes apoptosis of intestinal epithelial cells by suppressing the myeloid cell leukemia-1 (MCL1).

Conclusions: miR-125a/b shuttled by intestinal myofibroblasts derived exosomes regulate the proliferation and apoptosis of intestinal epithelial cells. GLP-2 treatment significantly decreases the level of miR-125a/b in the exosomes of intestinal myofibroblasts. miR-125a/b modulates the proliferation and apoptosis of intestinal epithelial cells by targeting the 3'UTR region of MCL1. Hence, this study indicates a novel mechanism of genetic exchange between cells in intestinal microenvironment.

Effects of p-coumaric acid on microRNA expression profiles in SNU-16 human gastric cancer cells

BACKGROUND

p-Coumaric acid (p-CA), a phenolic compound abundantly found in edible plants, was found to induce apoptosis in SNU-16 gastric cancer cells. However, the effects of p-CA on the microRNA expression pattern in SNU-16 cells have not been reported.

OBJECTIVES

The primary objective of this study was to investigate microRNA expression profiles in p-CA-treated SNU-16 cells.

METHODS

SNU-16 cells were treated with 1.5 mM p-CA for 48 h. High-throughput RNA sequencing was performed. The accuracy and validity of the RNA sequencing results were tested by real-time PCR. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using the differentially expressed microRNAs (DEMs).

RESULTS

Thirty-two DEMs were identified between p-CA-treated and control cells, 9 of which were upregulated, and 23 downregulated. GO and KEGG pathway analyses of the target genes indicated that these genes were involved in a variety of biological functions and several cancer-related pathways. The miRNA interactive network analysis identified hsa-miR-125a-5p, hsa-miR-30a-5p, and hsa-miR-7-5p as the major nodes.

CONCLUSIONS

Our findings indicated that p-CA exerted its anticancer effects in SNU-16 gastric cancer cells by modulating the expression of certain microRNAs, providing a better understanding of the anticancer properties of p-CA in gastric cancer cells.

miR-362-5p promotes cell proliferation and cell cycle progression by targeting GAS7 in acute myeloid leukemia

Recently, miR-362-5p has attracted special interest as a novel prognostic predictor in acute myeloid leukemia (AML). However, its biological function and underlying molecular mechanism in AML remain to be further defined. Herein, we found that a significant increase in miR-362-5p expression was observed in AML patients and cell lines using quantitative real-time PCR. The expression of miR-362-5p was altered in THP-1 and HL-60 cells by transfecting with miR-362-5p mimic or inhibitor. A series of experiments showed that inhibition of miR-362-5p expression significantly suppressed cell proliferation, induced G0/G1 phase arrest and attenuated tumor growth in vivo. On the contrary, ectopic expression of miR-362-5p resulted in enhanced cell proliferation, cell cycle progression and tumor growth. Moreover, growth arrest-specific 7 (GAS7) was confirmed as a direct target gene of miR-362-5p and was negatively modulated by miR-362-5p. GAS7 overexpression imitated the tumor suppressive effect of silenced miR-362-5p on THP-1 cells. Furthermore, miR-362-5p knockdown or GAS7 overexpression obviously down-regulated the expression levels of PCNA, CDK4 and cyclin D1, but up-regulated p21 expression. Collectively, our findings demonstrate that miR-362-5p exerts oncogenic effects in AML by directly targeting GAS7, which might provide a promising therapeutic target for AML.

Genome-wide miRNA profiling and pivotal roles of miRs 125a-5p and 17-92 cluster in human neutrophil maturation and differentiation of acute myeloid leukemia cells

MicroRNAs (miRNAs, miRs) are short non-coding post-transcriptional regulators of gene expression in normal physiology and disease. Acute myeloid leukemia is characterized by accumulation of malignantly transformed immature myeloid precursors, and differentiation therapy, used to overcome this differentiation blockage, has become a successful therapeutic option. The human HL-60 acute leukemia cell line serves as a cell culture model for granulocytic maturation, and dimethyl sulfoxide (DMSO) incubation leads to its differentiation towards neutrophil-like cells, as assessed by biochemical, functional and morphological parameters. DMSO-induced HL-60 cell differentiation constitutes an excellent model to examine molecular processes that turn a proliferating immortal leukemic cell line into mature non-proliferating and apoptosis-prone neutrophil-like end cells. By performing genome-wide miRNA profiling and functional assays, we have identified a signature of 86 differentially expressed canonical miRNAs (51 upregulated; 35 downregulated) during DMSO-induced granulocytic differentiation of HL-60 cells. Quantitative real-time PCR was used to validate miRNA expression. Among these differentially expressed canonical miRNAs, we found miR-125a-5p upregulation and miR-17-92 cluster downregulation acted as major regulators of granulocytic differentiation in HL-60 cells. Enforced expression of miR-125a-5p promoted granulocytic differentiation in HL-60 cells, whereas miR-17-92 ectopic expression inhibited DMSO-induced HL-60 granulocytic differentiation. Ectopic expression of miR-125a-5p also promoted granulocytic differentiation in human acute promyelocytic leukemia NB4 cells, as well as in naïve human primary CD34⁺-hematopoietic progenitor/stem cells. These findings provide novel molecular insights into the identification of miRNAs regulating granulocytic differentiation of human leukemia cells and normal CD34⁺-hematopoietic progenitor/stem cells, and may assist in the development of novel miRNA-targeted therapies for leukemia.

Mutational spectrum and associations with clinical features in patients with acute myeloid leukaemia based on next‑generation sequencing

The aim of the present study was to examine the associations between 112 acute myeloid leukaemia (AML)-associated genes and the prognosis and clinical features of AML using bioinformatics analysis in 62 patients with AML. A total of 61 gene mutations were identified, and ≥1 mutations were detected in 96.77% of the patients. A total of 11 frequent mutations were identified, including nucleophosmin 1 (NPM1), Fms related tyrosine kinase 3 (FLT3), DNA methyltransferase 3α (DNMT3A) and Notch 2 (NOTCH2), with a mutation rate of ≥10%. The FLT3 mutation was significantly associated with the white blood cell count at the time of diagnosis, and DNMT3A was significantly associated with the French-American-British subtype and cytogenetics of patients with AML. The FLT3, NPM1 and DNMT3A mutations were significantly associated with a poor overall survival (OS) in patients with AML. In addition, the co-mutation of DNMT3A-CCAAT enhancer binding protein α (CEBPA) was observed to be significantly associated with a poor OS in patients with AML. Furthermore, the functional enrichment analysis revealed that the co-mutations of FLT3-NOTCH2, SETBP1-CREBBP and DNMT3A-CEBPA were significantly enriched in processes of ‘negative regulation of cell differentiation’ and ‘immune system development’, indicating that these mutations may serve crucial roles in the diagnosis and treatment of AML.

Silence of long noncoding RNA NEAT1 exerts suppressive effects on immunity during sepsis by promoting microRNA-125-dependent MCEMP1 downregulation

Accumulating studies have recognized microRNAs (miRs) and long noncoding RNAs (lncRNAs) as important molecules involved in the mediation of various biological processes, including innate immunity. In this study, we investigated a novel noncoding RNA regulatory circuitry in the immunity during sepsis. A cecal ligation and puncture-induced sepsis mouse model was established to determine the expression of mast cell expression membrane protein 1 (MCEMP1). The RNA crosstalk among lncRNA nuclear enriched abundant transcript 1 (NEAT1), miR-125, and MCEMP1 was validated. Subsequently, the levels of lncRNA NEAT1, miR-125, and MCEMP1 in T lymphocytes isolated from sepsis mice were up- or downregulated by exogenous transfection in an attempt to investigate their effects on the release of inflammatory factors, the expression of immunoglobulins, the activity of T cell subsets and natural killer (NK) cells, as well as T lymphocyte apoptosis. In sepsis mice, MCEMP1 was highly expressed and verified to be a target gene of miR-125. RNA crosstalk experiment revealed that lncRNA NEAT1 directly inhibited miR-125 to upregulate MCEMP1. We also observed that elevation of miR-125, depletion of MCEMP1, or downregulation of lncRNA NEAT1 resulted in promoted T lymphocyte activity, immunoglobulin expression, and NK cell activity, and inhibited release of inflammatory factors and T lymphocyte apoptosis. Taken together, these findings provided evidence that the downregulation of lncRNA NEAT1 could promote miR-125 to exert an inhibitory effect on the immunity in septic mice by suppressing MCEMP1, highlighting a potential target for the treatment of sepsis. © 2019 IUBMB Life, 2019.

Antiproliferative Activity of microRNA-125a and its Molecular Targets

BACKGROUND

MicroRNA-125a is present in all animals with bilateral symmetry and displays a conserved nucleotide sequence with a section of 11 bases including the seed region that is identical in all considered species. It primarily downregulates the expression of LIN28, thereby promoting cell differentiation and larval phase transitions in nematodes, mammals and insects.

OBJECTIVE

In this review, we focus on the cellular control of miR-125a expression and its antiproliferative activity.

RESULTS

In mammalians, microRNA-125a is present in most adult organs and tissues in which it targets proteins involved in the mitogenic response, such as membrane receptors, intracellular signal transducers, or transcription factors, with the overall effect of inhibiting cell proliferation. Tissue levels of miR-125a generally raise during differentiation but it is often downregulated in cancers, e.g. colon, cervical, gastric, ovarian, lung, and breast cancers, osteosarcoma, neuroblastoma, glioblastoma, medulloblastoma, retinoblastoma and hepatocellular carcinoma.

CONCLUSION

The antiproliferative activity of miR-125a, demonstrated in many cell types, together with the notion that this miRNA is downregulated in several kinds of cancers, give a substantial support to the concept that miR-125a plays an oncosuppressive role.

OncomiR or antioncomiR: Role of miRNAs in Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is a hematopoietic progenitor/stem cell disorder in which neoplastic myeloblasts are stopped at an immature stage of differentiation and lost the normal ability of proliferation and apoptosis. MicroRNAs (miRNAs) are small noncoding, single-stranded RNA molecules that can mediate the expression of target genes. While miRNAs mean to contribute the developments of normal functions, abnormal expression of miRNAs and regulations on their corresponding targets have often been found in the developments of AML and described in recent years. In leukemia, miRNAs may function as regulatory molecules, acting as oncogenes or tumor suppressors. Overexpression of miRNAs can down-regulate tumor suppressors or other genes involved in cell differentiation, thereby contributing to AML formation. Similarly, miRNAs can down-regulate different proteins with oncogenic activity as tumor suppressors. We herein review the current data on miRNAs, specifically their targets and their biological function based on apoptosis in the development of AML.

The Network of Non-coding RNAs in Cancer Drug Resistance

Non-coding RNAs (ncRNAs) have been implicated in most cellular functions. The disruption of their function through somatic mutations, genomic imprinting, transcriptional and post-transcriptional regulation, plays an ever-increasing role in cancer development. ncRNAs, including notorious microRNAs, have been thus proposed to function as tumor suppressors or oncogenes, often in a context-dependent fashion. In parallel, ncRNAs with altered expression in cancer have been reported to exert a key role in determining drug sensitivity or restoring drug responsiveness in resistant cells. Acquisition of resistance to anti-cancer drugs is a major hindrance to effective chemotherapy and is one of the most important causes of relapse and mortality in cancer patients. For these reasons, non-coding RNAs have become recent focuses as prognostic agents and modifiers of chemo-sensitivity. This review starts with a brief outline of the role of most studied non-coding RNAs in cancer and then highlights the modulation of cancer drug resistance via known ncRNAs based mechanisms. We identified from literature 388 ncRNA-drugs interactions and analyzed them using an unsupervised approach. Essentially, we performed a network analysis of the non-coding RNAs with direct relations with cancer drugs. Within such a machine-learning framework we detected the most representative ncRNAs-drug associations and groups. We finally discussed the higher integration of the drug-ncRNA clusters with the goal of disentangling effectors from downstream effects and further clarify the involvement of ncRNAs in the cellular mechanisms underlying resistance to cancer treatments.

Epigenetics and Epi-miRNAs: Potential markers/therapeutics in leukemia

Epigenetic variations can play remarkable roles in different normal and abnormal situations. Such variations have been shown to have a direct role in the pathogenesis of various diseases either through inhibition of tumor suppressor genes or increasing the expression of oncogenes. Enzymes involving in epigenetic machinery are the main actors in tuning the epigenetic-based controls on gene expressions. Aberrant expression of these enzymes can trigger a big chaos in the cellular gene expression networks and finally lead to cancer progression. This situation has been shown in different types of leukemia, where high or low levels of an epigenetic enzyme are partly or highly responsible for involvement or progression of a disease. DNA hypermethylation, different histone modifications, and aberrant miRNA expressions are three main epigenetic variations, which have been shown to play a role in leukemia progression. Epigenetic based treatments now are considered as novel and effective therapies in order to decrease the abnormal epigenetic modifications in patient cells. Different epigenetic-based approaches have been developed and tested to inhibit or reverse the unusual expression of epigenetic agents in leukemia. The reciprocal behavior of miRNAs in the regulation of epigenetic modifiers, while being regulated by them, unlocks a new opportunity in order to design some epigenetic-based miRNAs able to silence or sensitize these effectors in leukemia.

Evaluation of the effect of TIM-3 suppression by miR-498 and its effect on apoptosis and proliferation rate of HL-60 cell line

BACKGROUND

Acute Myeloid Leukemia (AML) is a Cancer of hematopoietic stem cells with a rapid progression. TIM-3 is expressed on leukemic stem cells (LSCs) in most types of AML and might have a positive effect on maintenance of malignant phenotype. MicroRNAs play important roles in either cancer progression or suppression. In this study were evaluated, the inhibitory effect of miR-498 on TIM-3 expression and its impact on proliferation and survival of HL-60 cell line.

METHODS

Firstly, the probable inhibitory effect of miR-498 on TIM-3 expression was predicted. HL-60 cells were cultured and expression of TIM-3 was induced on the cells using phorbol miristate acetate. The cells were transfected with miR-498 and expression level of TIM-3 were measured using with q-RT-PCR and flow cytometry methods. In addition, the effect of suppression of TIM-3 expression in HL-60 cell line was analyzed with apoptosis and cell proliferation assays.

RESULTS

Bioinformatics analyses predicted that miR-498 has high ability to silence TIM-3 gene expression. Our experiments confirmed that miR-498 was able to strongly silence TIM-3 expression (68% silencing) in HL-60 cell line (P < 0.002). Also, the cells with suppressed expression of TIM-3 had a lower proliferation and higher apoptosis rates.

CONCLUSION

Based on our results, the miR-498 can effectively suppress TIM-3 expression in the AML cell line. TIM-3 suppression, in turn, inhibits malignant cell proliferation and induces its apoptosis. Collectively, suppression of TIM-3 by miR-498 can be considered as a potential powerful way for treatment of AML.

Knockdown of LncRNA-UCA1 suppresses chemoresistance of pediatric AML by inhibiting glycolysis through the microRNA-125a/hexokinase 2 pathway

Dysregulation of lncRNAs is implicated in chemoresistance in varieties of tumor including acute myeloid leukemia (AML). LncRNA urothelial carcinoma-associated 1 (UCA1) was reported to play an oncogenic role in AML. However, whether UCA1 was involved in chemoresistance in pediatric AML remains unclear. UCA1 expression in AML patients after adriamycin (ADR)-based chemotherapy and ADR-resistant AML cells was examined by qRT-PCR. The effects of UCA1 on the cytotoxicity of ADR and glycolysis were evaluated by MTT assay and measuring the glucose consumption and lactate production in HL60 and HL60/ADR cells, repectively. The protein levels of hypoxia-inducible factor 1α (HIF-1α) and hexokinase 2 (HK2) were determined by Western blot. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to confirm the relationships between UCA1, HK2, and miR-125a. We found that UCA1 expression was upregulated following ADR-based chemotherapy. Knockdown of UCA1 increased the cytotoxic effect of ADR and inhibited HIF-1α-dependent glycolysis in ADR-resistant AML cells. Additionally, UCA1 functioned as a ceRNA of miR-125a by directly binding to miR-125a. HK2, a target of miR-125a, was positively regulated by UCA1 in HL60 and HL60/ADR cells. More notably, UCA1 overexpression overturned miR-125-mediated inhibition on HIF-1α-dependent glycolysis in HL60 and HL60/ADR cells. Furthermore, 2-deoxy-glucose (2-DG) exposure inhibited HIF-1α-dependent glycolysis, and attenuated UCA1-induced increase of chemoresistance in HL60 and HL60/ADR cells. We conclude that knockdown of UCA1 plays a positive role in overcoming the chemoresistance of pediatric AML, through suppressing glycolysis by the miR-125a/HK2 pathway, contributing to a better understanding of the molecular mechanism of chemoresistance in AML.

Lowered expression of microRNA-125a-5p in human hepatocellular carcinoma and up-regulation of its oncogenic targets sirtuin-7, matrix metalloproteinase-11, and c-Raf

Human microRNA-125a-5p (miR-125a) is expressed in most tissues where it downregulates the expression of membrane receptors or intracellular transductors of mitogenic signals, thus limiting cell proliferation. Expression of this miRNA generally increases with cell differentiation whereas it is downregulated in several types of tumors, such as breast, lung, ovarian, gastric, colon, and cervical cancers, neuroblastoma, medulloblastoma, glioblastoma, and retinoblastoma. In this study, we focused on hepatocellular carcinoma and used real-time quantitative PCR to measure miR-125a expression in 55 tumor biopsies and in matched adjacent non-tumor liver tissues. This analysis showed a downregulation of miR-125a in 80 % of patients, with a mean decrease of 4.7-fold. Comparison of miRNA downregulation with clinicopathological parameters of patients didn't yield significant correlations except for serum bilirubin. We then evaluated the expression of known targets of miR-125a and found that sirtuin-7, matrix metalloproteinase-11, and c-Raf were up-regulated in tumor tissue by 2.2-, 3-, and 1.7-fold, respectively. Overall, these data support a tumor suppressor role for miR-125a and encourage further studies aimed at the comprehension of the molecular mechanisms governing its expression, eventually leading to treatments to restore its expression in tumor cells.

miRNAs in acute myeloid leukemia

MicroRNAs (miRNAs) are small, non-coding RNAs found throughout the eukaryotes that control the expression of a number of genes involved in commitment and differentiation of hematopoietic stem cells and tumorigenesis. Widespread dysregulation of miRNAs have been found in hematological malignancies, including human acute myeloid leukemia (AML). A comprehensive understanding of the role of miRNAs within the complex regulatory networks that are disrupted in malignant AML cells is a prerequisite for the development of therapeutic strategies employing miRNA modulators. Herein, we review the roles of emerging miRNAs and the miRNAs regulatory networks in AML pathogenesis, prognosis, and miRNA-directed therapies.

MicroRNA, an Antisense RNA, in Sensing Myeloid Malignancies

Myeloid malignancies, including myelodysplastic syndromes and acute myeloid leukemia, are clonal diseases arising in hematopoietic stem or progenitor cells. In recent years, microRNA (miRNA) expression profiling studies have revealed close associations of miRNAs with cytogenetic and molecular subtypes of myeloid malignancies, as well as outcome and prognosis of patients. However, the roles of miRNA deregulation in the pathogenesis of myeloid malignancies and how they cooperate with protein-coding gene variants in pathological mechanisms leading to the diseases have not yet been fully understood. In this review, we focus on recent insights into the role of miRNAs in the development and progression of myeloid malignant diseases and discuss the prospect that miRNAs may serve as a potential therapeutic target for leukemia.

miR-125a suppresses viability and glycolysis and induces apoptosis by targeting Hexokinase 2 in laryngeal squamous cell carcinoma

Background

miR-125a usually functions as a tumor suppressor in cancers. However, the role of miR-125a in laryngeal squamous cell carcinoma (LSCC) has not been determined.

Methods

qRT-PCR was applied to measure the expression of miR-125a and HK2 mRNA in LSCC tissues and cells. CCK-8 kit and flow cytometry analysis were performed to detect cell viability and apoptosis. Luciferase reporter assay and RNA immunoprecipitation (RIP) were conducted to confirm the relationship between miR-125a and HK2. Commercial test kits were used to determine the concentrations of glucose and l-lactate. Xenograft in mice was constructed to validate the function and mechanism of miR-125a in LSCC tumor growth.

Results

A negative correlation was found between miR-125a expression and the level of Hexokinase 2 (HK2) mRNA in LSCC tissues. Functional experiments found that miR-125a inhibited viability and glycolysis and induced apoptosis in LSCC cells. Similarly, HK2 downregulation led to viability and glycolysis inhibition and induction of apoptosis in LSCC cells in vitro. Moreover, miR-125a overexpression suppressed LSCC xenograft growth in vivo. Mechanically, HK2 was verified to be a target of miR-125a by luciferase reporter assays and RNA immunoprecipitation (RIP) assays. Furthermore, restored HK2 expression reversed miR-125a-mediated proliferation and glycolysis inhibition and induction of apoptosis in LSCC cells.

Conclusions

miR-125a suppressed LSCC progression by targeting HK2 in vitro and in vivo, suggesting that miR-125a may be a potential molecular target for LSCC treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13578-017-0178-y) contains supplementary material, which is available to authorized users.

Investigating the microRNA-mRNA regulatory network in acute myeloid leukemia

Acute myeloid leukemia (AML) is a common myelogenous malignancy in adults that is often characterized by disease relapse. The pathophysiological mechanism of AML has not yet been elucidated. The present study aimed to identify the crucial microRNAs (miRNAs/miRs) and target genes in AML, and to uncover the potential oncogenic mechanism of AML. miRNA and mRNA expression-profiling microarray datasets were downloaded from the Gene Expression Omnibus database. Differential expression analysis was performed and a regulatory network between miRNAs and target genes was constructed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were used to predict the biological functions of the differentially expressed genes. Reverse transcription-quantitative polymerase chain reaction analysis was employed to verify the expression levels of miRNAs and target genes in AML patient samples. A total of 86 differentially expressed miRNAs and 468 differentially expressed mRNAs between AML and healthy blood samples were identified. In total, 47 miRNAs and 401 mRNAs were found to be upregulated, and 39 miRNAs and 67 mRNAs were found to be downregulated in AML. A total of 223 miRNA-target genes pairs were subjected to the construction of a regulatory network. Differentially expressed target genes were significantly enriched in the Wnt signaling pathway (hsa04310), melanogenesis (hsa04916) and pathways in cancer (hsa05200). Significantly differentially expressed miRNAs and genes, including hsa-miR-155, hsa-miR-192, annexin A2 (ANXA2), frizzled class receptor 3 (FZD3), and pleomorphic adenoma gene 1 (PLAG1), may serve essential roles in AML oncogenesis. Overall, hsa-miR-155, hsa-miR-192, ANXA2, FZD3 and PLAG1 may be associated with the development of AML via the involvement of the Wnt signaling pathway, melanogenesis and other cancer-associated signaling pathways.

Molecular mechanisms governing microRNA-125a expression in human hepatocellular carcinoma cells

MicroRNA-125a-5p (miR-125a) is a vertebrate homolog of lin-4, the first discovered microRNA, and plays a fundamental role in embryo development by downregulating Lin-28 protein. MiR-125a is also expressed in differentiated cells where it generally acts as an antiproliferative factor by targeting membrane receptors or intracellular transductors of mitogenic signals. MiR-125a expression is downregulated in several tumors, including hepatocellular carcinoma (HCC) where it targets sirtuin-7, matrix metalloproteinase-11, VEGF-A, Zbtb7a, and c-Raf. In this study, we have isolated the transcription promoter of human miR-125a and characterized its activity in HCC cells. It is a TATA-less Pol II promoter provided with an initiator element and a downstream promoter element, located 3939 bp upstream the genomic sequence of the miRNA. The activity of the promoter is increased by the transcription factor NF-kB, a master regulator of inflammatory response, and miR-125a itself was found to strengthen this activation through inhibition of TNFAIP3, a negative regulator of NF-kB. This finding contributes to explain the increased levels of miR-125a observed in the liver of patients with chronic hepatitis B.

miR-125b predicts childhood acute lymphoblastic leukaemia poor response to BFM chemotherapy treatment

BACKGROUND

Despite the favourable survival rates of childhood acute lymphoblastic leukaemia (ALL), a significant number of patients present resistance to antileukaemic agents and dismal prognosis. In this study, we analysed miR-125b expression in childhood ALL and evaluated its clinical utility for patients treated with Berlin-Frankfurt-Münster (BFM) protocol.

METHODS

The study included 272 bone marrow specimens obtained on diagnosis and on BFM day 33 from 125 patients and 64 healthy children. Following extraction, RNA was polyadenylated and reverse transcribed. miR-125b levels were quantified by quantitative PCR. Cytogenetics, immunohistotype and MRD were analysed according to international guidelines.

RESULTS

Downregulated miR-125b levels were detected in childhood ALL patients and correlated with adverse prognosis. Following BFM induction, miR-125b levels were significantly increased, however, elevated day 33/diagnosis miR-125b ratio was associated with unfavourable disease features. Loss of miR-125b during diagnosis and higher day 33/diagnosis ratio were correlated with stronger risk for disease short-term relapse and patients' worse survival. Moreover, multivariate regression models highlighted the independent prognostic value of miR-125b for childhood ALL. Finally, the combination of miR-125b with clinically used disease markers clearly enhanced the prediction of patients' resistance to BFM chemotherapy.

CONCLUSIONS

miR-125b significantly improves the prognosis of childhood ALL patients' outcome under BFM treatment.

High expression of CPNE3 predicts adverse prognosis in acute myeloid leukemia

CPNE3, a member of a Ca²⁺‐dependent phospholipid‐binding protein family, was identified as a ligand of ERBB2 and has a more general role in carcinogenesis. Here, we identified the prognostic significance of CPNE3 expression in acute myeloid leukemia (AML) patients based on two datasets. In the first microarray dataset (n = 272), compared to low CPNE3 expression (CPNE3^low), high CPNE3 expression (CPNE3^high) was associated with adverse overall survival (OS, P < 0.001) and event‐free survival (EFS, P < 0.001). In the second independent group of AML patients (TCGA dataset, n = 179), CPNE3^high was also associated with adverse OS and EFS (OS, P = 0.01; EFS, P = 0.036). Notably, among CPNE3^high patients, those received allogenic hematopoietic cell transplantation (HCT) had longer OS and EFS than those with chemotherapy alone (allogeneic HCT, n = 40 vs chemotherapy, n = 46), but treatment modules played an insignificant role in the survival of CPNE3^low patients (allogeneic HCT, n = 32 vs chemotherapy, n = 54). These results indicated that CPNE3^high is an independent, adverse prognostic factor in AML and might guide treatment decisions towards allogeneic HCT. To understand its inherent mechanisms, we investigated genome‐wide gene/microRNA expression signatures and cell signaling pathways associated with CPNE3 expression. In conclusion, CPNE3^high is an adverse prognostic biomarker for AML. Its effect may be attributed to the distinctive genome‐wide gene/microRNA expression and related cell signaling pathways.

Cancer Hallmarks and MicroRNAs: The Therapeutic Connection

Human cancers are characterized by a number of hallmarks, including sustained proliferative signaling, evasion of growth suppressors, activated invasion and metastasis, replicative immortality, angiogenesis, resistance to cell death, and evasion of immune destruction. As microRNAs (miRNAs) are deregulated in virtually all human cancers, they show involvement in each of the cancer hallmarks as well. In this chapter, we describe the involvement of miRNAs in cancer from a cancer hallmarks and targeted therapeutics point of view. As no miRNA-based cancer therapeutics are available to date, and the only clinical trial on miRNA-based cancer therapeutics (MRX34) was terminated prematurely due to serious adverse events, we are focusing on protein-coding miRNA targets for which targeted therapeutics in oncology are already approved by the FDA. For each of the cancer hallmarks, we selected major protein-coding players and describe the miRNAs that target them.

MicroRNA: an important regulator in acute myeloid leukemia

MicroRNAs (miRNAs) are a general class of endogenous non-coding RNAs with a length of 22 nucleotides, widely existing in diverse species and playing important roles in malignancies initiation and progression. MiRNAs are essential to many in vivo biological processes such as cell proliferation, apoptosis, immune response, and tumorigenesis. Significant progress till date has been made in understanding the roles of microRNAs in normal hematopoiesis and hematopoietic malignant diseases. In this review, we summarize the particular signatures of microRNAs in acute myeloid leukemia (AML) patients with specific karyotype and the clinical significance of microRNAs in early diagnosis and treatment. MicroRNAs hypermethylation was also proved to correlate with the pathogenesis of AML. However, the target genes and exact pathways of microRNAs participating in these processes are still unknown and more efforts need to be made in the near future.

Involvement of miR-125a in resistance to daunorubicin by inhibiting apoptosis in leukemia cell lines

In this study, we investigated whether miR-125a participated in the resistance of the leukemia cell lines to the chemotherapeutic agent daunorubicin. Higher expression of miR-125a is correlated with lower treatment response and shorter overall survival in acute leukemia patients. Overexpression of miR-125a induced drug resistance in HL-60, K562, and THP-1cell lines through reducing apoptosis. We also showed that miR-125a mediated daunorubicin resistance in leukemia cell lines through the decrease of GRK2 and Puma which were proved to be direct targets of miR-125a. This study may provide novel therapeutic targets for therapy and improve predictions of therapeutic responses in leukemia to daunorubicin.

Curcumin Promotes Osteosarcoma Cell Death by Activating miR-125a/ERRα Signal Pathway

Curcumin has demonstrated valuable therapeutic potential against a variety of human cancers including osteosarcoma. However, the molecular mechanisms underlying its anti-tumor effect remain to be poorly understood. By RNA sequence profiling, we found that curcumin significantly down-regulates the expression of estrogen-related receptor alpha (ERRα) in osteosarcoma cells. Overexpression of ERRα diminished curcumin-activated apoptotic cell death and scavenged curcumin-induced reactive oxygen species (ROS), while ERRα silencing sensitized osteosarcoma cells to curcumin, resulting in increased inhibition of cell proliferation. In addition, we found that curcumin suppressed the ERRα gene expression through upregulation of miR-125a. Data from this study revealed a novel mechanism for curcumin-mediated apoptotic cell death, which involves tumor cell killing via activating miR-125a/ERRα pathway. Our studies also provide further support for osteosarcoma therapy by targeting ERRα alone or in combination with curcumin. J. Cell. Biochem. 118: 74-81, 2017. © 2016 Wiley Periodicals, Inc.

Therapeutic Resistance in Acute Myeloid Leukemia: The Role of Non-Coding RNAs

Acute myeloid leukemia (AML) is caused by malignant transformation of hematopoietic stem or progenitor cells and displays the most frequent acute leukemia in adults. Although some patients can be cured with high dose chemotherapy and allogeneic hematopoietic stem cell transplantation, the majority still succumbs to chemoresistant disease. Micro-RNAs (miRNAs) and long non-coding RNAs (lncRNAs) are non-coding RNA fragments and act as key players in the regulation of both physiologic and pathologic gene expression profiles. Aberrant expression of various non-coding RNAs proved to be of seminal importance in the pathogenesis of AML, as well in the development of resistance to chemotherapy. In this review, we discuss the role of miRNAs and lncRNAs with respect to sensitivity and resistance to treatment regimens currently used in AML and provide an outlook on potential therapeutic targets emerging thereof.

Comparison of microRNA expression profiles in K562-cells-derived microvesicles and parental cells, and analysis of their roles in leukemia

Microvesicles (MVs) are 30-1,000-nm extracellular vesicles that are released from a multitude of cell types and perform diverse cellular functions, including intercellular communication, antigen presentation, and transfer of proteins, messenger RNA and microRNA (also known as miR). MicroRNAs have been demonstrated to be aberrantly expressed in leukemia, and the overall microRNA expression profile may differentiate normal blood cells vs. leukemia cells. MVs containing microRNAs may enable intercellular cross-talk in vivo. This prompted us to investigate specific variations of microRNA expression patterns in MVs derived from leukemia cells. The present study examined the microRNA expression profile of MVs from chronic myeloid leukemia K562 cells and that of MVs from normal human volunteers' peripheral blood cells. The potential targets of the differentially expressed microRNAs were predicted using computational searches. Bioinformatic analyses of the predicted target genes were performed for further evaluation. The present study analyzed microRNAs of MVs derived from leukemia and normal cells, and characterized specific microRNAs expression. The results revealed that MVs derived from K562 cells expressed 181 microRNAs of the 888 microRNAs assessed. Further analysis revealed that 16 microRNAs were downregulated, while 7 were upregulated in these MVs. In addition, significant differences in microRNA expression profiles between MVs derived from K562 cells and K562 cells were identified. The present results revealed that 77 and 122 microRNAs were only expressed in MVs derived from K562 cells and in K562 cells, respectively. There were 104 microRNAs co-expressed in MVs derived from K562 cells and in K562 cells. Target gene-related pathway analyses demonstrated that the majority of the dysregulated microRNAs were involved in pathways associated with leukemia, particularly the mitogen-activated protein kinase (MAPK) and the p53 signaling pathways. By further conducting microRNA gene network analysis, the present study revealed that the miR-15a/b, miR-16, miR-17 and miR-30 families were likely to play a role in the regulation of the MAPK signaling pathway. Since K562 cells presented the t(9;22) translocation, the current study further examined the predicted function of 12 microRNAs located in chromosomes 9 [Homo sapiens (hsa)-let-7a, hsa-let-7f, miR-126, miR-126*, miR-23b, miR-24, miR-27b and miR-7] and 22 (hsa-let-7b, miR-1249, miR-130b and miR-185), which were expressed both in MVs derived from K562 cells and in K562 cells. The present study identified microRNAs of MVs from leukemia and normal cells, and characterized the expression of specific microRNAs. The current study is also the first to identify and characterize distinct microRNA expression between MVs derived from K562 cells and K562 cells. These findings highlight that a number of microRNAs from leukemia-derived MVs may contribute to the development of hematopoietic malignancies. Further investigation may reveal the function of these differentially expressed microRNAs and may provide potential targets for novel therapeutic strategies.

The miR-125a-3p Inhibits TIM-3 Expression in AML Cell Line HL-60 In Vitro

Acute Myeloid Leukemia is a cancer of leukemic stem cells (LSCs) with a rapid progression. It is characterized by overproduction of immature myeloid cells in bone marrow which crowds out normal hematopoietic stem cells (HSC). TIM-3, an immune regulatory molecule, is an LSC specific surface marker in AML with high expression on these cells compared to HSCs. Studies have indicated that micro RNAs (miRNAs) may play an important role in either cancer progression or suppression. Based on bioinformatics assessments, we have predicted that miR-125a-3p could be a miRNA with high suppressive activity on TIM-3 expression. The purpose of this study was to investigate the inhibitory effect of miR-125a-3p on TIM-3 gene expression in an AML cell line, HL-60, in vitro. HL-60 cells were cultured in RPMI 1640 supplied with 10 % FBS. TIM-3 expression was induced on the cells using phorbol miristate acetate. The cells were transfected with miR-125-3p for 24 h and the gene and protein expression of TIM-3 were measured using q-RT-PCR and flow-cytometery methods, respectively. The results of this study showed that miR-125a-3p has a strong silencing effect on TIM-3 gene and protein expression on HL-60 cell line. Based to our results, miR125a-3p can strongly silence TIM-3 expression in AML cell line. Thus, our results have confirmed the bioinformatics prediction of suppressive effect of miR-125a-3p on TIM-3with Mirwalk and Target Scan softwares.

Gender Differences in Adipocyte Metabolism and Liver Cancer Progression

Liver cancer is the third most common cancer type and the second leading cause of deaths in men. Large population studies have demonstrated remarkable gender disparities in the incidence and the cumulative risk of liver cancer. A number of emerging risk factors regarding metabolic alterations associated with obesity, diabetes and dyslipidemia have been ascribed to the progression of non-alcoholic fatty liver diseases (NAFLD) and ultimately liver cancer. The deregulation of fat metabolism derived from excessive insulin, glucose, and lipid promotes cancer-causing inflammatory signaling and oxidative stress, which eventually triggers the uncontrolled hepatocellular proliferation. This review presents the current standing on the gender differences in body fat compositions and their mechanistic linkage with the development of NAFLD-related liver cancer, with an emphasis on genetic, epigenetic and microRNA control. The potential roles of sex hormones in instructing adipocyte metabolic programs may help unravel the mechanisms underlying gender dimorphism in liver cancer and identify the metabolic targets for disease management.

SVCT2, a potential therapeutic target, protects against oxidative stress during ethanol-induced neurotoxicity via JNK/p38 MAPKs, NF-κB and miRNA125a-5p

Sodium vitamin C transporter 2 (SVCT2) plays a key role in transporting ascorbic acid (AA), an important intracellular antioxidant, into neurons. It is well known that ethanol (EtOH) abuse causes significant neurodegeneration, as well as endogenous AA release in certain encephalic regions. Here, we identified that SVCT2 forms part of a self-defense mechanism that protects against oxidative stress in binge drinking rats, and SVCT2 levels are correlated with antioxidants and neuronal injury. Four days of binge drinking led to massive neuron degeneration in prefrontal cortex (PFC), accompanied by increased levels of 4-hydroxynonenal (4-HNE)-adducted proteins and SVCT2 expression, as well as dramatic changes in AA levels in rat brain. AA levels were decreased in PFC and increased in cerebrospinal fluid (CSF) after binge drinking, but returned to normal on the 7th day following EtOH withdrawal. These processes were further evaluated in primary cortical neurons exposed to 100mM EtOH in vitro. Neurons transfected with SVCT2 siRNA were more susceptible than controls to certain aspects of EtOH-induced injury, including cell death, dendrite damage and increased oxidative stress. EtOH-induced up-regulation of SVCT2 was associated with activation of JNK and p38 MAPKs and the NF-κB pathway. More importantly, miRNA-125a-5p was down-regulated in PFC of 4-day binge drinking rats and negatively regulated protein expression during EtOH-induced neuronal injury. MiR-125a-5p over-expression attenuated intracellular AA levels, promoted cell death and suppressed the EtOH-induced up-regulation of p38 MAPK and SVCT2, which suggested that miR-125a-5p plays an important role in SVCT2 function in EtOH-induced neuronal injury. We speculate that SVCT2, possibly regulated by JNK/p38 MAPKs, NF-κB signaling and miR-125a-5p, has a neuroprotective effect against EtOH-induced oxidative stress. Promotion of SVCT2 expression or stimulation of SVCT2 activity may be a promising therapeutic strategy for the prevention of EtOH-associated neurodegeneration.

Neuregulin-1 signaling is essential for nerve-dependent axolotl limb regeneration

The Mexican axolotl (Ambystoma mexicanum) is capable of fully regenerating amputated limbs, but denervation of the limb inhibits the formation of the post-injury proliferative mass called the blastema. The molecular basis behind this phenomenon remains poorly understood, but previous studies have suggested that nerves support regeneration via the secretion of essential growth-promoting factors. An essential nerve-derived factor must be found in the blastema, capable of rescuing regeneration in denervated limbs, and its inhibition must prevent regeneration. Here, we show that the neuronally secreted protein Neuregulin-1 (NRG1) fulfills all these criteria in the axolotl. Immunohistochemistry and in situ hybridization of NRG1 and its active receptor ErbB2 revealed that they are expressed in regenerating blastemas but lost upon denervation. NRG1 was localized to the wound epithelium prior to blastema formation and was later strongly expressed in proliferating blastemal cells. Supplementation by implantation of NRG1-soaked beads rescued regeneration to digits in denervated limbs, and pharmacological inhibition of NRG1 signaling reduced cell proliferation, blocked blastema formation and induced aberrant collagen deposition in fully innervated limbs. Taken together, our results show that nerve-dependent NRG1/ErbB2 signaling promotes blastemal proliferation in the regenerating limb and may play an essential role in blastema formation, thus providing insight into the longstanding question of why nerves are required for axolotl limb regeneration.

The downregulation of miR‑125a‑5p functions as a tumor suppressor by directly targeting MMP‑11 in osteosarcoma

Osteosarcoma is one of the most common primary malignant bone cancers in juveniles and adults. Increasingly, reports indicate that microRNAs (miRNAs) may provide novel therapeutic targets for cancer treatment. The aim of the present study was to investigate the expression of miR‑125a‑5p and to identify its functional significance in osteosarcoma. This indicated that miR‑125a‑5p was downregulated in osteosarcoma tissue and cell lines using reverse transcription‑quantitative polymerase chain reaction. Following transfection with miR‑125a‑5p mimics or the negative control, cell migration, invasion and epithelial‑mesenchymal transition (EMT) assays were conducted in osteosarcoma cells. These results indicated that the overexpression of miR‑125a‑5p resulted in inhibited osteosarcoma cell migration, invasion and EMT in vitro. Furthermore, mechanistic studies showed that matrix metallopeptidase‑11 (MMP‑11), was a direct target of miR‑125a‑5p in osteosarcoma. Taken together, the data demonstrate that miR‑125a‑5p functions as a tumor suppressor gene and serves an important role in inhibiting osteosarcoma cell migration, invasion and EMT by targeting MMP‑11.

The HER2 inhibitor TAK165 Sensitizes Human Acute Myeloid Leukemia Cells to Retinoic Acid-Induced Myeloid Differentiation by activating MEK/ERK mediated RARα/STAT1 axis

The success of all-trans retinoic acid (ATRA) in differentiation therapy for patients with acute promyelocytic leukemia (APL) highly encourages researches to apply this therapy to other types of acute myeloid leukemia (AML). However, AML, with the exception of APL, fails to respond to differentiation therapy. Therefore, research strategies to further sensitize cells to retinoids and to extend the range of AMLs that respond to retinoids beyond APLs are urgently needed. In this study, we showed that TAK165, a HER2 inhibitor, exhibited a strong synergy with ATRA to promote AML cell differentiation. We observed that TAK165 sensitized the AML cells to ATRA-induced cell growth inhibition, G0/G1 phase arrest, CD11b expression, mature morphologic changes, NBT reduction and myeloid regulator expression. Unexpectedly, HER2 pathway might not be essential for TAK165-enhanced differentiation when combined with ATRA, while the enhanced differentiation was dependent on the activation of the RARα/STAT1 axis. Furthermore, the MEK/ERK cascade regulated the activation of STAT1. Taken together, our study is the first to evaluate the synergy of TAK165 and ATRA in AML cell differentiation and to assess new opportunities for the combination of TAK165 and ATRA as a promising approach for future differentiation therapy.

Particulate Air Pollution Exposure and Expression of Viral and Human MicroRNAs in Blood: The Beijing Truck Driver Air Pollution Study

BACKGROUND

MicroRNAs (miRNAs) are post-transcriptional gene suppressors and potential mediators of environmental effects. In addition to human miRNAs, viral miRNAs expressed from latent viral sequences are detectable in human cells.

OBJECTIVE

In a highly exposed population in Beijing, China, we evaluated the associations of particulate air pollution exposure on blood miRNA profiles.

METHODS

The Beijing Truck Driver Air Pollution Study (BTDAS) included 60 truck drivers and 60 office workers. We investigated associations of short-term air pollution exposure, using measures of personal PM2.5 (particulate matter ≤ 2.5 μm) and elemental carbon (EC), and ambient PM10 (≤ 10 μm), with blood NanoString nCounter miRNA profiles at two exams separated by 1-2 weeks.

RESULTS

No miRNA was significantly associated with personal PM2.5 at a false discovery rate (FDR) of 20%. Short-term ambient PM10 was associated with the expression of 12 miRNAs in office workers only (FDR < 20%). Short-term EC was associated with differential expression of 46 human and 7 viral miRNAs, the latter including 3 and 4 viral miRNAs in office workers and truck drivers, respectively. EC-associated miRNAs differed between office workers and truck drivers with significant effect modification by occupational group. Functional interaction network analysis suggested enriched cellular proliferation/differentiation pathways in truck drivers and proinflammation pathways in office workers.

CONCLUSIONS

Short-term EC exposure was associated with the expression of human and viral miRNAs that may influence immune responses and other biological pathways. Associations between EC exposure and viral miRNA expression suggest that latent viral miRNAs are potential mediators of air pollution-associated health effects. PM2.5/PM10 exposures showed no consistent relationships with miRNA expression.