miR-181a modulates acute myeloid leukemia susceptibility to natural killer cells

The Effects of Resveratrol, Gallic Acid, and Piperine on the Expression of miR-17, miR-92b, miR-181a, miR-222, BAX, BCL-2, MCL-1, WT1, c-Kit, and CEBPA in Human Acute Myeloid Leukemia Cells and Their Roles in Apoptosis

MicroRNAs (miRs) play a crucial role in the leukemogenesis and the prognosis of acute myeloid leukemia (AML). This study investigated the therapeutic effects of resveratrol, gallic acid, and piperine as natural anticancer agents on the HL-60 cell line and their roles in apoptosis. In this experimental study, quantitative analysis of miRs, including miR-17, miR-92b, miR-181a, and miR-222, were performed in 150 newly diagnosed patients with AML by real-time PCR assay. HL-60 cell viability as well as the expression of miRs, BAX, BCL-2, MCL-1, WT1, c-Kit, and CEBPA, were also assessed after transfection with the LNA-miRs and treatment with resveratrol, gallic acid, and piperine. The expression of miR-17 and miR-181a decreased significantly in LNA-anti-miRs. Although HL-60 cell viability decreased in LNA-anti-miR-222, miR-17, and miR-92b, blockade of miR-181a increased the cell viability. Besides, the cell viability increased merely in the piperine-treated group. Compared to untreated cells, miR-17 and miR-92b expression significantly increased in gallic acid- and resveratrol-treated cells. In HL-60 cells treated with resveratrol, gallic acid, and piperine, the expression of miR-181a was also increased significantly. The expression of BAX was also increased in resveratrol and piperine-treated groups. Compared to untreated cells, the expression of c-Kit increased significantly in the piperine-treated group; however, it decreased in the resveratrol-treated group. LNA-anti-miRs may be a promising agent for the treatment of AML. All three compounds used in this study showed anticancer effects, which can exert the desired outcome in patients with AML.

microRNA expression in acute myeloid leukaemia: New targets for therapy?

Recent studies have shown that short non-coding RNAs, known as microRNAs (miRNAs) and their dysregulation, are implicated in the pathogenesis of acute myeloid leukaemia (AML). This is due to their role in the control of gene expression in a variety of molecular pathways. Therapies involving miRNA suppression and replacement have been developed. The normalisation of expression and the subsequent impact on AML cells have been investigated for some miRNAs, demonstrating their potential to act as therapeutic targets. Focussing on miRs with therapeutic potential, we have reviewed those that have a significant impact on the aberrant biological processes associated with AML, and crucially, impact leukaemic stem cell survival. We describe six miRNAs in preclinical trials (miR-21, miR-29b, miR-126, miR-181a, miR-223 and miR-196b) and two miRNAs that are in clinical trials (miR-29 and miR-155). However none have been used to treat AML patients and greater efforts are needed to develop miRNA therapies that could benefit AML patients in the future.

miR-149-3p suppressed epithelial-mesenchymal transition and tumor development in acute myeloid leukemia

OBJECTIVE

Acute myeloid leukemia (AML) is a form of primary acute leukemia with high mortality. Our previous study demonstrated that miR-149-3p was down-regulated in chemoresistant acute leukemia cells. However, the biological function of miR-149-3p in AML needs to be further explored.

METHODS

Herein, the expression of miR-149-3p was overexpressed/silenced in U-937 human AML cells via transfection with miR-149-3p agomir/antagomir. The effect of miR-149-3p on U-937-induced tumor growth was investigated using a xenograft nude mouse model.

RESULTS

The results showed that miR-149-3p overexpression inhibited the proliferation and increased the apoptosis of U-937 cells. In addition, miR-149-3p suppressed epithelial-mesenchymal transition in U-937 cells, as demonstrated by the miR-149-3p agomir-induced increase in E-cadherin expression and decrease in vimentin expression. The in vivo experiments demonstrated that miR-149-3p suppressed tumor progression.

CONCLUSION

In conclusion, the findings revealed the association of miR-149-3p with the development of AML and suggest that miR-149-3p is a potential therapeutic candidate for AML.

Identification of Acute Myeloid Leukemia Bone Marrow Circulating MicroRNAs

BACKGROUND

In addition to their roles in different biological processes, microRNAs in the tumor microenvironment appear to be potential diagnostic and prognostic biomarkers for various malignant diseases, including acute myeloid leukemia (AML). To date, no screening of circulating miRNAs has been carried out in the bone marrow compartment of AML. Accordingly, we investigated the circulating miRNA profile in AML bone marrow at diagnosis (AMLD) and first complete remission post treatment (AMLPT) in comparison to healthy donors (HD).

METHODS

Circulating miRNAs were isolated from AML bone marrow aspirations, and a low-density TaqMan miRNA array was performed to identify deregulated miRNAs followed by quantitative RT-PCR to validate the results. Bioinformatic analysis was conducted to evaluate the diagnostic and prognostic accuracy of the highly and significantly identified deregulated miRNA(s) as potential candidate biomarker(s).

RESULTS

We found several deregulated miRNAs between the AMLD vs. HD vs. AMLPT groups, which were involved in tumor progression and immune suppression pathways. We also identified significant diagnostic and prognostic signatures with the ability to predict AML patient treatment response.

CONCLUSIONS

This study provides a possible role of enriched circulating bone marrow miRNAs in the initiation and progression of AML and highlights new markers for prognosis and treatment monitoring.

MN1, FOXP1 and hsa-miR-181a-5p as prognostic markers in acute myeloid leukemia patients treated with intensive induction chemotherapy and autologous stem cell transplantation

BACKGROUND

The meningioma-1 (MN1) gene is expressed in hematopoietic CD34+ cells and down-regulated during myeloid differentiation. MN1 overexpression has been linked to shorter overall and disease free survival in AML patients treated with intensive induction chemotherapy. MN1 overexpression may still be an adverse prognostic marker in AML patients treated with autologous stem cell transplant (auto-SCT) after intensive induction chemotherapy.

METHODS

We retrospectively analysed 54 peripheral blood mononuclear cell (PBMC) samples of AML patients who received auto-SCT at remission (CR1) after intensive induction chemotherapy. MN1 and putative MN1-associated mRNAs, as well as MN1-associated micro-RNAs were assessed at diagnosis in peripheral blood mononuclear cells using Taqman gene expression assays.

RESULTS

AML patients with elevated MN1 or FoxP1 gene expression at diagnosis had a significantly shorter progression-free and overall survival after intensive induction chemo-therapy and auto-SCT. The presence of the favourable risk NPM1 mutation associated with reduced MN1 gene expression. In contrast to MN1 and FOXP1, elevated expression of the putative tumor suppressive micro-RNA hsa-miR-181a-5p was predictive for positive outcome. Correlation analysis of MN1 with myeloid gene expression levels revealed association of MN1 and BMI-1, CD34, FOXP1 and MDM2 expression. Analysis of non-coding RNAs revealed an inverse correlation of MN1 with hsa-miR-20a-5p and hsa-miR-181b-5p expression.

CONCLUSIONS

MN1, FOXP1 and hsa-miR-181a-5p are prognostic markers in AML patients treated with intensive induction chemotherapy and auto-SCT. While MDM2 is a validated therapeutic target, the transcription factors MN1 and FOXP1, and the chromatin modulator BMI-1 are potential therapeutic targets in the treatment of AML. The tumor suppressor hsa-miR-181a-5p may be a candidate miRNA mimic for therapeutic use.

Altered expression of miR-181 affects cell fate and targets drug resistance-related mechanisms

MicroRNAs (miRNAs) are non-coding transcripts which regulate genetic and epigenetic events by interfering with mRNA translation. miRNAs are involved in regulation of cell fate due to their ability of interfering with physiological or pathological processes. In this review paper, we evaluate the role of miR-181 family members as prognostic or diagnostic markers or therapeutic targets in malignant pathologies in connection with the main hallmarks of cancer that are modulated by the family. Also, we take over the dual role of this family in dependency with the tumour suppressor and oncogenic features presented in cell and cancer type specific manner. Restoration of the altered expression levels contributes to the activation of cell death pathways or to a reduction in the invasion and migration mechanism; moreover, the mechanism of drug resistance is also modulated by miR-181 sequences with important applications in therapeutic strategies for malignant cells sensitisation. Overall, the main miR-181 family regulatory mechanisms are presented in a cancer specific context, emphasizing the possible clinical application of this family in terms of novel diagnosis and therapy approaches.

MicroRNA regulation of natural killer cell development and function in leukemia

MicroRNAs (miRNAs) are now recognized as important regulators of all cellular processes, including immune function and cancer survival. These evolutionary preserved, single-stranded, non-coding RNA molecules mediate important functional effects primarily through post-transcriptional regulation of protein expression. MiRNAs are known to mediate multiple oncogenic pathways in tumor cells, both tumor promoting and tumor suppressing. In addition to a direct tumor cell effect, miRNAs have also been shown to play a critical role in immune cell development, function and survival. Here we expand on previous reports to evaluate miRNA regulation in natural killer (NK) cells primarily in humans and focus on their influence on NK cell development and function in the setting of hematologic malignancies. In addition, we highlight the most recent miRNA discoveries in hematologic malignancies and discuss areas of future exploration relevant to the translational field of innate immunology and miRNA-based therapeutic intervention.

Hypoxia- and MicroRNA-Induced Metabolic Reprogramming of Tumor-Initiating Cells

Colorectal cancer (CRC), the second most common cause of cancer mortality in the Western world, is a highly heterogeneous disease that is driven by a rare subpopulation of tumorigenic cells, known as cancer stem cells (CSCs) or tumor-initiating cells (TICs). Over the past few years, a plethora of different approaches, aimed at identifying and eradicating these self-renewing TICs, have been described. A focus on the metabolic and bioenergetic differences between TICs and less aggressive differentiated cancer cells has thereby emerged as a promising strategy to specifically target the tumorigenic cell compartment. Extrinsic factors, such as nutrient availability or tumor hypoxia, are known to influence the metabolic state of TICs. In this review, we aim to summarize the current knowledge on environmental stress factors and how they affect the metabolism of TICs, with a special focus on microRNA (miRNA)- and hypoxia-induced effects on colon TICs.

Selection of three miRNA signatures with prognostic value in non-M3 acute myeloid leukemia

BACKGROUND

MiRNAs that are potential biomarkers for predicting prognosis for acute myeloid leukemia (AML) have been identified. However, comprehensive analyses investigating the association between miRNA expression profiles and AML survival remain relatively deficient.

METHOD

In the present study, we performed multivariate Cox's analysis and principal component analysis (PCA) using data from The Cancer Genome Atlas (TCGA) to identify potential molecular signatures for predicting non-M3 AML prognosis.

RESULT

We found that patients who were still living were significantly younger at diagnosis than those who had died (P = 0.001). In addition, there was a marked difference in living status among different risk category groups (P = 0.022). A multivariate Cox model suggested that three miRNAs were potential biomarkers of non-M3 AML prognosis, including miR-181a-2, miR-25 and miR-362. Subsequently, PCA analyses were conducted to comprehensively represent the expression levels of these three miRNAs in each patient with a PCA value. According to the log-rank test, AML outcome for patients with lower PCA values was significantly different from those with higher PCA values (P < 0.001). Further bioinformatic analysis revealed the biological functions of the selected miRNAs.

CONCLUSION

We conducted a comprehensive analysis of TCGA non-M3 AML data, identifying three miRNAs that are significantly correlated with AML survival. PCA values for the identified miRNAs are valuable for predicting AML prognosis.

miR-181a-5p suppresses invasion and migration of HTR-8/SVneo cells by directly targeting IGF2BP2

Pre-eclampsia is a pregnancy-related disease that may cause maternal, neonatal and fetal morbidity and mortality and exists in 3–5% of pregnancies worldwide. The discovery of dysregulated microRNAs and their roles in placental development has provided a new avenue for elucidating the mechanism involved in this pregnancy-specific disorder. Here, the roles of human miR-181a-5p, a microRNA that is increased in both the plasma and placenta of severe pre-eclamptic patients, in invasion and migration of trophoblasts were investigated. Ectopic-expression of miR-181a-5p impaired the invasion and migration of HTR-8/SVneo cells, whereas miR-181a-5p inhibition had the opposite effects. IGF2BP2, which harbors a highly conserved miR-181a-5p-binding site within its 3ʹ-UTR, was identified to be directly inhibited by miR-181a-5p. Moreover, siRNAs targeting IGF2BP2 imitated the effects of overexpressed miR-181a-5p on HTR-8/SVneo cell invasion and migration, whereas restoring IGF2BP2 expression by overexpressing a plasmid encoding IGF2BP2 partially reversed the studied inhibitory functions of miR-181a-5p. Thus, we demonstrated here that miR-181a-5p suppresses the invasion and migration of cytotrophoblasts, and its inhibitory effects were at least partially mediated by the suppression of IGF2BP2 expression, thus shedding new light on the roles of miR-181a-5p in the pathogenesis of severe pre-eclampsia.

microRNAs and Acute Myeloid Leukemia Chemoresistance: A Mechanistic Overview

Up until the early 2000s, a functional role for microRNAs (miRNAs) was yet to be elucidated. With the advent of increasingly high-throughput and precise RNA-sequencing techniques within the last two decades, it has become well established that miRNAs can regulate almost all cellular processes through their ability to post-transcriptionally regulate a majority of protein-coding genes and countless other non-coding genes. In cancer, miRNAs have been demonstrated to play critical roles by modifying or controlling all major hallmarks including cell division, self-renewal, invasion, and DNA damage among others. Before the introduction of anthracyclines and cytarabine in the 1960s, acute myeloid leukemia (AML) was considered a fatal disease. In decades since, prognosis has improved substantially; however, long-term survival with AML remains poor. Resistance to chemotherapy, whether it is present at diagnosis or induced during treatment is a major therapeutic challenge in the treatment of this disease. Certain mechanisms such as DNA damage response and drug targeting, cell cycling, cell death, and drug trafficking pathways have been shown to be further dysregulated in treatment resistant cancers. miRNAs playing key roles in the emergence of these drug resistance phenotypes have recently emerged and replacement or inhibition of these miRNAs may be a viable treatment option. Herein, we describe the roles miRNAs can play in drug resistant AML and we describe miRNA-transcript interactions found within other cancer states which may be present within drug resistant AML. We describe the mechanisms of action of these miRNAs and how they can contribute to a poor overall survival and outcome as well. With the precision of miRNA mimic- or antagomir-based therapies, miRNAs provide an avenue for exquisite targeting in the therapy of drug resistant cancers.

MicroRNA-181 as a prognostic biomarker for survival in acute myeloid leukemia: a meta-analysis

Accumulating evidence has indicated that microRNA-181 (miR-181) is dysregulated in hematological malignancies, and associates with the clinical outcomes. However, the association of miR-181 expression levels with acute myeloid leukemia (AML) remains inconclusive, as publications from different groups have reported contradictory results. In this manuscript, a meta-analysis was performed to assess the prognostic significance of miR-181 in AML patients. Eligible studies were retrieved from PubMed, Embase and Cochrane Library databases, and a total of 6 studies including 815 AML patients were included in the final analysis. Hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were extracted and pooled to investigate the correlation between miR-181 and the survival of AML patients. Our results showed that elevated miR-181 expression was associated with increased survival in 395 American patients, and reduced survival in 325 Chinese patients. Both subgroup analyses and meta-regression indicated that the origin of AML patients contributed to the heterogeneity in the datasets evaluating the correlation between overall survival (OS) and miR-181. These results indicate that miR-181 can be used as a promising prognostic biomarker in AML patients, which may depend on the origin of patient population.

An overview of the potential strategies for NK cell-based immunotherapy for acute myeloid leukemia

Patients with acute myeloid leukemia (AML) have relatively low survival rates compared to patients with other pediatric cancers. Relapse is frequent with conventional treatment and is a major cause of morbidity and mortality. Natural killer (NK) cells offer an alternative approach to chemotherapy that combats relapse by substantially eradicating AML blasts. New methods for enhancing NK cell activation and expression of the activating ligand on target malignant cells will increase the likelihood of success with this approach. We review these latest discoveries in NK cell-based therapy for AML and delineate recent advances in sensitizing AML cells to NK cell-mediated immunosurveillance.

Underground Adaptation to a Hostile Environment: Acute Myeloid Leukemia vs. Natural Killer Cells

Acute myeloid leukemia (AML) is a heterogeneous group of malignancies which incidence increases with age. The disease affects the differentiation of hematopoietic stem or precursor cells in the bone marrow and can be related to abnormal cytogenetic and/or specific mutational patterns. AML blasts can be sensitive to natural killer (NK) cell antitumor response. However, NK cells are frequently defective in AML patients leading to tumor escape. NK cell defects affect not only the expression of the activating NK receptors, including the natural cytotoxicity receptors, the NK group 2, member D, and the DNAX accessory molecule-1, but also cytotoxicity and IFN-γ release. Such perturbations in NK cell physiology could be related to the adaptation of the AML to the immune pressure and more generally to patient’s clinical features. Various mechanisms are potentially involved in the inhibition of NK-cell functions in AML, including defects in the normal lymphopoiesis, reduced expression of activating receptors through cell-to-cell contacts, and production of immunosuppressive soluble agents by leukemic blasts. Therefore, the continuous cross-talk between AML and NK cells participates to the leukemia immune escape and eventually to patient’s relapse. Methods to restore or stimulate NK cells seem to be attractive strategies to treat patients once the complete remission is achieved. Moreover, our capacity in stimulating the NK cell functions could lead to the development of preemptive strategies to eliminate leukemia-initiating cells before the emergence of the disease in elderly individuals presenting preleukemic mutations in hematopoietic stem cells.