Decreased expression of microRNA-122 is associated with an unfavorable prognosis in childhood acute myeloid leukemia and function analysis indicates a therapeutic potential

A novel therapeutic strategy: the significance of exosomal miRNAs in acute myeloid leukemia

Acute myeloid leukemia (AML) is a fast-growing blood cancer that interferes with the normal growth of blood cells in the bone marrow and blood. It is characterized by its unpredictable outlook and high death rate. The main treatment for AML is chemotherapy, but this often results in drug resistance and the possibility of the disease returning. For this reason, new biomarkers are necessary to diagnose, predict, and treat this disease. Research has demonstrated that cells responsible for AML release exosomes that interact with the disease's microenvironment. These exosomes have significant roles in promoting leukemia growth, suppressing normal hematopoiesis, facilitating angiogenesis, and contributing to drug resistance in AML. Further investigations have shown that these exosomes contain miRNAs, which are transferred to target cells and have functional roles. Biomarkers are utilized to assess various aspects of tumor cell behavior, including proliferation, apoptosis, angiogenesis, changes in the microenvironment, transfer of drug resistance, and stability in serum and blood plasma. In this research, we showed that exosomal miRNAs and exosomes have the potential to be used as indicators for detecting various phases of AML and can aid in its medical treatment. Furthermore, they can be specifically targeted for therapeutic purposes in addressing this condition.

MicroRNA-122 in human cancers: from mechanistic to clinical perspectives

MicroRNAs (miRNAs) are endogenous short non-coding RNAs that can regulate the expression of target genes post-transcriptionally and interact with mRNA-coding genes. MiRNAs play vital roles in many biological functions, and abnormal miRNA expression has been linked to various illnesses, including cancer. Among the miRNAs, miR-122, miR-206, miR-21, miR-210, miR-223, and miR-424 have been extensively studied in various cancers. Although research in miRNAs has grown considerably over the last decade, much is yet to be discovered, especially regarding their role in cancer therapies. Several kinds of cancer have been linked to dysregulation and abnormal expression of miR-122, indicating that miR-122 may serve as a diagnostic and/or prognostic biomarker for human cancer. Consequently, in this review literature, miR-122 has been analyzed in numerous cancer types to sort out the function of cancer cells miR-122 and enhance patient response to standard therapy.

Expression analysis of circulating miR-22, miR-122, miR-217 and miR-367 as promising biomarkers of acute lymphoblastic leukemia

BACKGROUND

The role of serum-based biomarkers such as microRNAs in cancer diagnosis has been extensively established. This study aimed to determine the expression levels of bioinformatically selected miRNAs and whether they can be used as biomarkers or a new therapeutic target in patients with acute lymphoblastic leukemia (ALL).

MATERIALS AND METHODS

The expression levels of serum miR-22, miR-122, miR-217, and miR-367 in 21 ALL patients and 21 healthy controls were measured using quantitative real-time PCR. The receiver operating characteristic (ROC) curve and the associated area under the curve (AUC) was used to assess candidate miRNAs' diagnostic value as a biomarker.

RESULTS

The results showed that miR-217 was markedly decreased in patients with ALL compared to controls. Moreover, miR-22, miR-122, and miR-367 were found to be upregulated. Furthermore, ROC analysis showed that serum miR-217 and miR-367 could differentiate ALL patients from healthy individuals, while miR-22 has approximate discriminatory power that requires further investigation.

CONCLUSION

These results provide promising preliminary evidence that circulating miR-217 and miR-367 could be considered potent diagnostic biomarkers and therapeutic goals in this disease.

Regulation of miR-126 and miR-122 Expression and Response of Imatinib Treatment on Its Expression in Chronic Myeloid Leukemia Patients

BACKGROUND

MicroRNAs (miRNAs) have been observed to exhibit altered expression patterns in chronic myeloid leukemia (CML). Therefore, this study was aimed to evaluate the clinical importance of miR-126 and miR-122 expression in concert to imatinib response in CML patients.

METHODS

The present study included 100 CML and 100 healthy subjects. The expression of the 2 miRNAs was performed using TaqMan probe chemistry, and snU6 was used as internal control.

RESULTS

The expression of miR-126 and miR-122 was downregulated in CML patients, with a mean fold change ± SD 0.20 ± 0.33 and 0.22 ± 0.37, respectively. While the expression of both miRNAs was analysed before and after imatinib treatment, it was observed that the expression levels of both were increased after imatinib treatment by 26.25-fold (5.33 against 0.20) and 13.95-fold (3.07 against 0.22) and the increase was statistically significant (p < 0.0001 and p < 0.0001, respectively). The expression of miR-126 was not conclusive when compared in different clinical stages of the CML disease as it showed a decreased expression in patients with accelerated phase compared to chronic phase (mean fold change = 0.03 and 0.27, respectively), but patients with chronic phase and blastic phase had comparable expression (mean fold change = 0.27 and 0.24, respectively). We also observed an increased expression of both miRNAs after imatinib therapy in each clinical phase.

CONCLUSION

The study concludes that expression of miR-126 and miR-122 increases after imatinib treatment in CML patients and that miR-126 defines the good responders of imatinib therapy.

Long non‑coding RNA ZEB2‑AS1 affects cell proliferation and apoptosis via the miR‑122‑5p/PLK1 axis in acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous disease featured by the clonal accumulation of immature myeloid cells. Zinc finger E‑box binding homeobox 2 (ZEB2)‑antisense RNA 1 (AS1) has been verified to participate in the progression of several types of cancer, including AML. However, the potential mechanisms of ZEB2‑AS1 in AML have not yet been fully elucidated. The present study aimed to elucidate the role and regulatory mechanisms of ZEB2‑AS1 in AML. The expression of ZEB2‑AS1, microRNA‑122‑5p (miRNA/miR‑122‑5p) and polo‑like kinase 1 (PLK1) was detected by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) in AML tissues or cells. Cell proliferation and apoptosis were examined by methyl thiazolyl tetrazolium (MTT) assay and apoptosis assay, respectively. The protein levels were examined by western blot analysis. The targeted sequence between miR‑122‑5p and ZEB2‑AS1 or PLK1 was predicted using an online database and verified by dual‑luciferase reporter assay. A mouse tumor xenograft model was established to confirm the effects of ZEB2‑AS1 on tumor growth in vivo. The results revealed that the expression levels of ZEB2‑AS1 and PLK1 were upregulated, while those of miR‑122‑5p were downregulated in AML tissues and cells. The knockdown of ZEB2‑AS1 inhibited proliferation and induced apoptosis in vitro, and inhibited tumor growth in vivo. By experimental verification, ZEB2‑AS1 was found to negatively regulate miR‑122‑5p expression and PLK1 was found to be a target gene of miR‑122‑5p. Furthermore, ZEB2‑AS1 was verified to regulate the expression of PLK1 by sponging miR‑122‑5p in AML cells. On the whole, the findings of the present study demonstrate that ZEB2‑AS1 promotes cell proliferation and inhibits apoptosis, at least partly by targeting PLK1 mediated by miR‑122‑5p in AML cells.

MiR-100 regulates cell viability and apoptosis by targeting ATM in pediatric acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common pediatric malignancy and a major cause of morbidity and mortality in children. miR-100 is associated with progression of various diseases including AML. The aim of this study was to explore the underlying molecule mechanisms of miR-100 involved in AML. The expressions of miR-100 and ataxia telangiectasia mutated (ATM) in pediatric AML patients and cell lines were monitored using qRT-PCR and western blot assays. MTT assay was carried to evaluate cell viability. Cell apoptosis was measured by flow cytometry. The binding sites between miR-100 and ATM were predicted by mirtarbase database. Luciferase reporter assay was used to confirm the relationship between miR-100 and ATM. miR-100 expression was highly expressed in bone marrow of AML patients and cell lines. Moreover, Knockdown of miR-100 led to the inhibition of viability and promotion of apoptosis in Kasumi-1 and MV-4-11 cells. miR-100 harbored the 3'UTR of ATM. Meanwhile, the expression of ATM was downregulated in bone marrow of AML patients and AML cell lines. Subsequently, a negative correlation between miR-100 and ATM in bone marrow of AML patients was also observed. Furthermore, ectopic expression of ATM repressed cell viability while enhanced apoptosis. Notably, loss of ATM attenuated the effect of miR-100 depletion on cell viability and apoptosis in AML cells. miR-100 participates in cell viability and apoptosis by targeting ATM in pediatric AML.

Role of microRNAs, circRNAs and long noncoding RNAs in acute myeloid leukemia

Acute myeloid leukemia (AML) is a malignant tumor of the immature myeloid hematopoietic cells in the bone marrow (BM). It is a highly heterogeneous disease, with rising morbidity and mortality in older patients. Although researches over the past decades have improved our understanding of AML, its pathogenesis has not yet been fully elucidated. Long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) are three noncoding RNA (ncRNA) molecules that regulate DNA transcription and translation. With the development of RNA-Seq technology, more and more ncRNAs that are closely related to AML leukemogenesis have been discovered. Numerous studies have found that these ncRNAs play an important role in leukemia cell proliferation, differentiation, and apoptosis. Some may potentially be used as prognostic biomarkers. In this systematic review, we briefly described the characteristics and molecular functions of three groups of ncRNAs, including lncRNAs, miRNAs, and circRNAs, and discussed their relationships with AML in detail.

Clinical value of miRNA-122 in the diagnosis and prognosis of various types of cancer

The present study aimed to systematically analyze the value of microRNA-122 (miRNA-122) in the diagnosis and prognosis of hepatocellular carcinoma (HCC) and other types of cancer. First, the reverse transcription-quantitative polymerase chain reaction method was used to detect the expression levels of miRNA-122 in the serum samples of patients with HCC, benign lesions and healthy volunteers. Next, miRNA-seq data of miRNA-122 from The Cancer Genome Atlas database were used to analyze the differential expression and overall survival rate associated with a variety of types of cancer. Meanwhile, the target gene prediction of miRNA-122 was performed using four different software programs. Finally, 353 significant target genes were identified for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis. Finally, it was demonstrated that the expression levels of miRNA-122 in the HCC group were increased compared with the healthy group (P<0.001), but decreased with respect to the benign group (P<0.001). In addition, the combination of the miRNA-122 and a fetoprotein may further improve the diagnostic accuracy between the HCC and healthy groups (area under the curve, 0.980; 95% confidence interval, 0.958–1.000). It was also demonstrated that miRNA-122 exhibited significantly differential expression and the overall survival rate was predicted for various other types of cancer, including colorectal cancer, renal carcinoma, cholangiocarcinoma, prostate cancer and thyroid carcinoma. Functional enrichment analysis demonstrated that the target genes of miRNA-122 may contribute to the composition of the nucleus and cytoplasm, and regulate a variety of biological processes, including cardiac muscle cell differentiation and glucose metabolic processes via protein biosynthesis, estrogen and glucagon associated signaling pathways. These results revealed that miRNA-122 may be an indispensable biomarker for the diagnosis, prognostic evaluation and targeted therapy in pan-cancer.

MicroRNA in leukemia: Tumor suppressors and oncogenes with prognostic potential

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

MiRNA Dysregulation in Childhood Hematological Cancer

For decades, cancer biology focused largely on the protein-encoding genes that have clear roles in tumor development or progression: cell-cycle control, apoptotic evasion, genome instability, drug resistance, or signaling pathways that stimulate growth, angiogenesis, or metastasis. MicroRNAs (miRNAs), however, represent one of the more abundant classes of cell modulators in multicellular organisms and largely contribute to regulating gene expression. Many of the ~2500 miRNAs discovered to date in humans regulate vital biological processes, and their aberrant expression results in pathological and malignant outcomes. In this review, we highlight what has been learned about the roles of miRNAs in some of the most common human pediatric leukemias and lymphomas, along with their value as diagnostic/prognostic factors.

Lower expression of bone marrow miR-122 is an independent risk factor for overall survival in cytogenetically normal acute myeloid leukemia

BACKGROUND

The liver-enriched microRNA-122 (miR-122) plays a crucial role in pathogenesis of hepatocellular carcinoma (HCC) with prognostic value. Recently, miR-122 was also found to be related to many other cancers besides HCC. However, less study determined miR-122 expression and its clinical significance in acute myeloid leukemia (AML).

METHODS

Real-time quantitative PCR was performed to detect the level of bone marrow (BM) miR-122 in de novo AML patients. The clinical significance of miR-122 expression in AML was further investigated.

RESULTS

Among whole-cohort AML, lower expression of BM miR-122 was associated with male patients, higher hemoglobin and favorable-karyotypes (P = 0.038, 0.006, and 0.038, respectively). Among cytogenetically normal AML (CN-AML), lower expression of BM miR-122 was correlated with DNMT3A wild type (P = 0.043). Moreover, patients with lower expression of BM miR-122 presented lower complete remission (CR) rate and shorter overall survival (OS) than those with higher expression of BM miR-122 in CN-AML (P = 0.025 and 0.013, respectively). Cox regression analyses further confirmed the prognostic value of BM miR-122 expression in CN-AML (P = 0.024). In follow-up patients, BM miR-122 expression level in CR time was increased compared to diagnosis time, and was returned to primary level when in relapse time again (P = 0.062 and 0.049, respectively).

CONCLUSIONS

Our findings indicated that lower expression of BM miR-122 acted as an independent risk factor for OS in CN-AML.

MicroRNAs as New Biomarkers for Diagnosis and Prognosis, and as Potential Therapeutic Targets in Acute Myeloid Leukemia

Acute myeloid leukemias (AML) are clonal disorders of hematopoietic progenitor cells which are characterized by relevant heterogeneity in terms of phenotypic, genotypic, and clinical features. Among the genetic aberrations that control disease development there are microRNAs (miRNAs). miRNAs are small non-coding RNAs that regulate, at post-transcriptional level, translation and stability of mRNAs. It is now established that deregulated miRNA expression is a prominent feature in AML. Functional studies have shown that miRNAs play an important role in AML pathogenesis and miRNA expression signatures are associated with chemotherapy response and clinical outcome. In this review we summarized miRNA signature in AML with different cytogenetic, molecular and clinical characteristics. Moreover, we reviewed the miRNA regulatory network in AML pathogenesis and we discussed the potential use of cellular and circulating miRNAs as biomarkers for diagnosis and prognosis and as therapeutic targets.