MicroRNA-221 sensitizes chronic myeloid leukemia cells to imatinib by targeting STAT5

Non-coding RNAs in leukemia drug resistance: new perspectives on molecular mechanisms and signaling pathways

Like almost all cancer types, timely diagnosis is needed for leukemias to be effectively cured. Drug efflux, attenuated drug uptake, altered drug metabolism, and epigenetic alterations are just several of the key mechanisms by which drug resistance develops. All of these mechanisms are orchestrated by up- and downregulators, in which non-coding RNAs (ncRNAs) do not encode specific proteins in most cases; albeit, some of them have been found to exhibit the potential for protein-coding. Notwithstanding, ncRNAs are chiefly known for their contribution to the regulation of physiological processes, as well as the pathological ones, such as cell proliferation, apoptosis, and immune responses. Specifically, in the case of leukemia chemo-resistance, ncRNAs have been recognized to be responsible for modulating the initiation and progression of drug resistance. Herein, we comprehensively reviewed the role of ncRNAs, specifically its effect on molecular mechanisms and signaling pathways, in the development of leukemia drug resistance.

Obesity and Leukemia: Biological Mechanisms, Perspectives, and Challenges

PURPOSE OF REVIEW

To examine the epidemiological data on obesity and leukemia; evaluate the effect of obesity on leukemia outcomes in childhood acute lymphoblastic leukemia (ALL) survivors; assess the potential mechanisms through which obesity may increase the risk of leukemia; and provide the effects of obesity management on leukemia. Preventive (diet, physical exercise, obesity pharmacotherapy, bariatric surgery) measures, repurposing drugs, candidate therapeutic agents targeting oncogenic pathways of obesity and insulin resistance in leukemia as well as challenges of the COVID-19 pandemic are also discussed.

RECENT FINDINGS

Obesity has been implicated in the development of 13 cancers, such as breast, endometrial, colon, renal, esophageal cancers, and multiple myeloma. Leukemia is estimated to account for approximately 2.5% and 3.1% of all new cancer incidence and mortality, respectively, while it represents the most frequent cancer in children younger than 5 years. Current evidence indicates that obesity may have an impact on the risk of leukemia. Increased birthweight may be associated with the development of childhood leukemia. Obesity is also associated with worse outcomes and increased mortality in leukemic patients. However, there are several limitations and challenges in meta-analyses and epidemiological studies. In addition, weight gain may occur in a substantial number of childhood ALL survivors while the majority of studies have documented an increased risk of relapse and mortality among patients with childhood ALL and obesity. The main pathophysiological pathways linking obesity to leukemia include bone marrow adipose tissue; hormones such as insulin and the insulin-like growth factor system as well as sex hormones; pro-inflammatory cytokines, such as IL-6 and TNF-α; adipocytokines, such as adiponectin, leptin, resistin, and visfatin; dyslipidemia and lipid signaling; chronic low-grade inflammation and oxidative stress; and other emerging mechanisms. Obesity represents a risk factor for leukemia, being among the only known risk factors that could be prevented or modified through weight loss, healthy diet, and physical exercise. Pharmacological interventions, repurposing drugs used for cardiometabolic comorbidities, and bariatric surgery may be recommended for leukemia and obesity-related cancer prevention.

The predictive value of MiR-221 in cancer chemoresistance: a systematic review and meta-analysis

BACKGROUND

Many studies have reported that microRNA-221 (miR-221) is abnormally expressed in various cancers, and there has not been a study to systematically analyze the association between miR-221 and chemoresistance in different cancers.

METHODS

We systematically searched PubMed, Web of Science, Ovid, and Cochrane for relevant studies. The pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate.

RESULTS

A total of 30 studies with 1670 patients were enrolled in our study. Thirteen cancer types have been studied, and traditional chemotherapy, targeted drugs, endocrine therapy, chemoradiotherapy, and other treatments were used. High miR-221 expression was associated with poor chemotherapy response in most studies, and the meta-analysis confirmed this result (OR = 3.64, 95%CI: 1.73-7.62, p = 0.001). Besides, the higher level of miR-221 was related to shorter overall survival (OS) (HR = 2.16, 95%CI: 1.47-3.16, p < 0.001) and progression-free survival (PFS) (HR = 1.81, 95%CI: 1.51-2.16, p < 0.001) in patients after chemotherapy.

CONCLUSION

Our results highlight that high miR-221 expression has possible associations with chemoresistance and poor prognosis in multiple cancers. Further studies are needed to discover the molecular mechanisms underlying these associations to provide a solid evidence base for it being used as biomarkers of response to chemotherapeutic interventions in cancer.

Pharmacological impact of microRNAs in head and neck squamous cell carcinoma: Prevailing insights on molecular pathways, diagnosis, and nanomedicine treatment

Head and neck squamous cell carcinoma is a disease that most commonly produce tumours from the lining of the epithelial cells of the lips, larynx, nasopharynx, mouth, or oro-pharynx. It is one of the most deadly forms of cancer. About one to two percent of all neo-plasm-related deaths are attributed to head and neck squamous cell carcinoma, which is responsible for about six percent of all cancers. MicroRNAs play a critical role in cell proliferation, differentiation, tumorigenesis, stress response, triggering apoptosis, and other physiological process. MicroRNAs regulate gene expression and provide new diagnostic, prognostic, and therapeutic options for head and neck squamous cell carcinoma. In this work, the role of molecular signaling pathways related to head and neck squamous cell carcinoma is emphasized. We also provide an overview of MicroRNA downregulation and overexpression and its role as a diagnostic and prognostic marker in head and neck squamous cell carcinoma. In recent years, MicroRNA nano-based therapies for head and neck squamous cell carcinoma have been explored. In addition, nanotechnology-based alternatives have been discussed as a promising strategy in exploring therapeutic paradigms aimed at improving the efficacy of conventional cytotoxic chemotherapeutic agents against head and neck squamous cell carcinoma and attenuating their cytotoxicity. This article also provides information on ongoing and recently completed clinical trials for therapies based on nanotechnology.

The Promising Role of Non-Coding RNAs as Biomarkers and Therapeutic Targets for Leukemia

Early-stage leukemia identification is crucial for effective disease management and leads to an improvement in the survival of leukemia patients. Approaches based on cutting-edge biomarkers with excellent accuracy in body liquids provide patients with the possibility of early diagnosis with high sensitivity and specificity. Non-coding RNAs have recently received a great deal of interest as possible biomarkers in leukemia due to their participation in crucial oncogenic processes such as proliferation, differentiation, invasion, apoptosis, and their availability in body fluids. Recent studies have revealed a strong correlation between leukemia and the deregulated non-coding RNAs. On this basis, these RNAs are also great therapeutic targets. Based on these advantages, we tried to review the role of non-coding RNAs in leukemia. Here, the significance of several non-coding RNA types in leukemia is highlighted, and their potential roles as diagnostic, prognostic, and therapeutic targets are covered.

Intracellular angiopoietin-1 promotes TKI-resistance via activation of JAK/STAT5 pathway in chronic myeloid leukemia

Drug resistance from BCR-ABL tyrosine kinase inhibitors (TKIs) and other chemotherapeutics results in treatment failure and disease progression in chronic myeloid leukemia (CML). However, the mechanism is still uncertain. In this study, we investigated the role of angiopoietin-1 (ANG-1) as a potential prognostic factor for drug resistance in CML. Both intracellular and secretory ANG-1 (iANG-1 and sANG-1) were overexpressed in multidrug-resistant CML samples. The IC₅₀ value was higher in primary CD34⁺ CD38^- cells with more ANG-1. Silencing ANG-1significantly sensitized three TKI-resistant CML cell lines to imatinib (IM) while recombinant human ANG-1 failed to retain cell survival in vitro. This indicated the important role of iANG-1 as opposed to sANG-1 in CML drug resistance. Moreover, a similar effect was observed in xenograft mice models bearing ANG-1-silenced CML cells. Subsequently, pathway analysis and protein validation experiments showed activation of the JAK/STAT pathway and augmentation of STAT5a phosphorylation in ANG-1 restored CML cells. Upstream Src phosphorylation, which plays a crucial role in CML drug resistance, was also upregulated as a key event in iANG-1-related JAK/STAT pathway activation. In conclusion, our study elucidated a new BCR-ABL independent molecular mechanism induced by intracytoplasmic ANG-1 overexpression as a potential strategy for overcoming CML resistance.

Exosomal microRNAs in cancer: Potential biomarkers and immunotherapeutic targets for immune checkpoint molecules

Exosomes are small extracellular vesicles with a lipid bilayer structure secreted from different cell types which can be found in various body fluids including blood, pleural fluid, saliva and urine. They carry different biomolecules including proteins, metabolites, and amino acids such as microRNAs which are small non-coding RNAs that regulate gene expression and promote cell-to-cell communication. One main function of the exosomal miRNAs (exomiRs) is their role in cancer pathogenesis. Alternation in exomiRs expression could indicate disease progression and can regulate cancer growth and facilitate drug response/resistance. It can also influence the tumour microenvironment by controlling important signaling that regulating immune checkpoint molecules leading to activation of T cell anti-tumour immunity. Therefore, they can be used as potential novel cancer biomarkers and innovative immunotherapeutic agents. This review highlights the use of exomiRs as potential reliable biomarkers for cancer diagnosis, treatment response and metastasis. Finally, discuses their potential as immunotherapeutic agents to regulate immune checkpoint molecules and promote T cell anti-tumour immunity.

Antileukemic Activity of hsa-miR-203a-5p by Limiting Glutathione Metabolism in Imatinib-Resistant K562 Cells

Imatinib has been the first and most successful tyrosine kinase inhibitor (TKI) for chronic myeloid leukemia (CML), but many patients develop resistance to it after a satisfactory response. Glutathione (GSH) metabolism is thought to be one of the factors causing the emergence of imatinib resistance. Since hsa-miR-203a-5p was found to downregulate Bcr-Abl1 oncogene and also a link between this oncogene and GSH metabolism is reported, the present study aimed to investigate whether hsa-miR-203a-5p could overcome imatinib resistance by targeting GSH metabolism in imatinib-resistant CML cells. After the development of imatinib-resistant K562 (IR-K562) cells by gradually exposing K562 (C) cells to increasing doses of imatinib, resistant cells were transfected with hsa-miR-203a-5p (R+203). Thereafter, cell lysates from various K562 cell sets (imatinib-sensitive, imatinib-resistant, and miR-transfected imatinib-resistant K562 cells) were used for GC-MS-based metabolic profiling. L-alanine, 5-oxoproline (also known as pyroglutamic acid), L-glutamic acid, glycine, and phosphoric acid (Pi)-five metabolites from our data, matched with the enumerated 28 metabolites of the MetaboAnalyst 5.0 for the GSH metabolism. All of these metabolites were present in higher concentrations in IR-K562 cells, but intriguingly, they were all reduced in R+203 and equated to imatinib-sensitive K562 cells (C). Concludingly, the identified metabolites associated with GSH metabolism could be used as diagnostic markers.

Non-Coding RNAs Are Implicit in Chronic Myeloid Leukemia Therapy Resistance

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm initiated by the presence of the fusion gene BCR::ABL1. The development of tyrosine kinase inhibitors (TKIs) highly specific to p210^BCR-ABL1, the constitutively active tyrosine kinase encoded by BCR::ABL1, has greatly improved the prognosis for CML patients. Now, the survival rate of CML nearly parallels that of age matched controls. However, therapy resistance remains a persistent problem in the pursuit of a cure. TKI resistance can be attributed to both BCR::ABL1 dependent and independent mechanisms. Recently, the role of non-coding RNAs (ncRNAs) has been increasingly explored due to their frequent dysregulation in a variety of malignancies. Specifically, microRNAs (miRNAs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs) have been shown to contribute to the development and progression of therapy resistance in CML. Since each ncRNA exhibits multiple functions and is capable of controlling gene expression, they exert their effect on CML resistance through a diverse set of mechanisms and pathways. In most cases ncRNAs with tumor suppressing functions are silenced in CML, while those with oncogenic properties are overexpressed. Here, we discuss the relevance of many aberrantly expressed ncRNAs and their effect on therapy resistance in CML.

Micro-RNAs Predict Response to Systemic Treatments in Metastatic Renal Cell Carcinoma Patients: Results from a Systematic Review of the Literature

Locally advanced or metastatic renal cell carcinomas (mRCCs) account for up to 15% of all kidney cancer diagnoses. Systemic therapies (with or without surgery) represent gold standard treatments, mostly based on tyrosine kinase inhibitors in association with immunotherapy. We provide an overview of the current knowledge of miRNAs as predictors of treatment resistance. A systematic review of the literature was carried out in January 2022 following the PICO methodology. Overall, we included seven studies—four testing plasmatic miRNAs, two exosomal miRNAs, and one urinary miRNA. A total of 789 patients were included (354 for plasmatic miRNAs, 366 for urinary miRNAs, and 69 for exosomal miRNAs). Several miRNAs were tested within the included studies, but six plasmatic (miR9-5-p¸ miR-192, miR193-3p, miR-501-3p¸ miR-221, miR-376b-3p) one urinary (miR-30a-5p), and three exosomal (miR-35-5p, miR-301a-3p, miR-1293) were associated with resistance to systemic treatments or treatment failure in mRCC patients. Results showed a fair accuracy of these biomarkers in predicting treatment resistance and overall survival. However, to date, the biomarkers tested have not been validated and their clinical uses are not recommended. Nevertheless, the literature results are encouraging; future large clinical trials are warranted to validate the effectiveness of these tools in clinical decision-making.

Implication of microRNAs in Carcinogenesis with Emphasis on Hematological Malignancies and Clinical Translation

MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs, that are involved in the multistep process of carcinogenesis, contributing to all established hallmarks of cancer. In this review, implications of miRNAs in hematological malignancies and their clinical utilization fields are discussed. As components of the complex regulatory network of gene expression, influenced by the tissue microenvironment and epigenetic modifiers, miRNAs are “micromanagers” of all physiological processes including the regulation of hematopoiesis and metabolic pathways. Dysregulated miRNA expression levels contribute to both the initiation and progression of acute leukemias, the metabolic reprogramming of malignantly transformed hematopoietic precursors, and to the development of chemoresistance. Since they are highly stable and can be easily quantified in body fluids and tissue specimens, miRNAs are promising biomarkers for the early detection of hematological malignancies. Besides novel opportunities for differential diagnosis, miRNAs can contribute to advanced chemoresistance prediction and prognostic stratification of acute leukemias. Synthetic oligonucleotides and delivery vehicles aim the therapeutic modulation of miRNA expression levels. However, major challenges such as efficient delivery to specific locations, differences of miRNA expression patterns between pediatric and adult hematological malignancies, and potential side effects of miRNA-based therapies should be considered.

A Systematic Review of Candidate miRNAs, Its Targeted Genes and Pathways in Chronic Myeloid Leukemia-An Integrated Bioinformatical Analysis

Chronic myeloid leukaemia is blood cancer due to a reciprocal translocation, resulting in a BCR-ABL1 oncogene. Although tyrosine kinase inhibitors have been successfully used to treat CML, there are still cases of resistance. The resistance occurred mainly due to the mutation in the tyrosine kinase domain of the BCR-ABL1 gene. However, there are still many cases with unknown causes of resistance as the etiopathology of CML are not fully understood. Thus, it is crucial to figure out the complete pathogenesis of CML, and miRNA can be one of the essential pathogeneses. The objective of this study was to systematically review the literature on miRNAs that were differentially expressed in CML cases. Their target genes and downstream genes were also explored. An electronic search was performed via PubMed, Scopus, EBSCOhost MEDLINE, and Science Direct. The following MeSH (Medical Subject Heading) terms were used: chronic myeloid leukaemia, genes and microRNAs in the title or abstract. From 806 studies retrieved from the search, only clinical studies with in-vitro experimental evidence on the target genes of the studied miRNAs in CML cells were included. Two independent reviewers independently scrutinised the titles and abstracts before examining the eligibility of studies that met the inclusion criteria. Study design, sample size, sampling type, and the molecular method used were identified for each study. The pooled miRNAs were analysed using DIANA tools, and target genes were analysed with DAVID, STRING and Cytoscape MCODE. Fourteen original research articles on miRNAs in CML were included, 26 validated downstream genes and 187 predicted target genes were analysed and clustered into 7 clusters. Through GO analysis, miRNAs’ target genes were localised throughout the cells, including the extracellular region, cytosol, and nucleus. Those genes are involved in various pathways that regulate genomic instability, proliferation, apoptosis, cell cycle, differentiation, and migration of CML cells.

MiR-199a-3p Overexpression Suppressed Cell Proliferation and Sensitized Chronic Myeloid Leukaemia Cells to Imatinib by Inhibiting mTOR Signalling

INTRODUCTION

Chronic myeloid leukaemia (CML) is a myeloproliferative neoplasm characterized by constitutive activity of the tyrosine kinase BCR-ABL1. Drug resistance remains one of the major challenges in CML therapy. MicroRNA (miR)-199a-3p plays an important role in many tumours but has rarely been investigated in CML. We aimed to analyse the role and mechanism of miR-199a-3p in regulating imatinib resistance in CML.

METHODS

The expression of miR-199a-3p and mammalian target of rapamycin (mTOR) in the serum of CML patients and CML cells was examined by quantitative real-time polymerase chain reaction. The levels of apoptosis-related proteins were determined using western blot. The relative cell survival rate and cell proliferation were determined using a CCK-8 assay and a bromodeoxyuridine (BrdU) assay, respectively. Cell cycle and apoptosis were analysed using flow cytometry. Moreover, a dual-luciferase reporter assay was performed to verify the correlation between miR-199a-3p and mTOR.

RESULTS

MiR-199a-3p was downregulated in the serum of CML patients and in CML cells, while mTOR was upregulated. Both miR-199a-3p overexpression and mTOR silencing inhibited CML cell proliferation, promoted CML cell apoptosis, and sensitized these cells to imatinib. mTOR silencing reversed the promoting effect of miR-199a-3p inhibition on the proliferation of CML cells and the inhibitory effects on cell apoptosis and sensitivity to imatinib. MiR-199a-3p directly targeted mTOR.

CONCLUSION

MiR-199a-3p suppressed cell propagation, facilitated apoptosis of CML cells, and sensitized CML cells to imatinib by downregulating mTOR signalling.

miR-221/222 as biomarkers and targets for therapeutic intervention on cancer and other diseases: A systematic review

Among deregulated microRNAs (miRs) in human malignancies, miR-221 has been widely investigated for its oncogenic role and as a promising biomarker. Moreover, recent evidence suggests miR-221 as a fine-tuner of chronic liver injury and inflammation-related events. Available information also supports the potential of miR-221 silencing as promising therapeutic intervention. In this systematic review, we selected papers from the principal databases (PubMed, MedLine, Medscape, ASCO, ESMO) between January 2012 and December 2020, using the keywords "miR-221" and the specific keywords related to the most important hematologic and solid malignancies, and some non-malignant diseases, to define and characterize deregulated miR-221 as a valuable therapeutic target in the modern vision of molecular medicine. We found a major role of miR-221 in this view.

Lessons from microRNA biology: Top key cellular drivers of Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Numerous microRNAs (miRs), small RNAs that target several pathways, have been implicated in the development of Autosomal Dominant Polycystic Kidney Disease (ADPKD), which is the most common genetic cause of kidney failure. The hallmark of ADPKD is tissue overgrowth and hyperproliferation, eventually leading to kidney failure.

SCOPE OF THE REVIEW

Many miRs are dysregulated in disease, yet the intracellular pathways regulated by miRs are less well described in ADPKD. Here, I summarise all the differentially expressed miRs in ADPKD and highlight the top miR-regulated cellular driver of disease.

MAJOR CONCLUSIONS

Literature review has identified 53 abnormally expressed miRs in ADPKD. By performing bioinformatics analysis of their target genes I present 10 key intracellular pathways that drive ADPKD progression. The top key drivers are divided into three main areas: (i) hyperproliferation and the role of JAK/STAT and PI3K pathways (ii) DNA damage and (iii) inflammation and NFκB.

GENERAL SIGNIFICANCE

The description of the 10 top cellular drivers of ADPKD, derived by analysis of miR signatures, is of paramount importance in better understanding the key processes resulting in pathophysiological changes that underlie disease.

Proteomics analysis reveals the correlation of programmed ROS-autophagy loop and dysregulated G1/S checkpoint with imatinib resistance in chronic myeloid leukemia cells

Although tyrosine kinase inhibitors (TKIs), including imatinib, have greatly improved clinical treatment of patients with chronic myeloid leukemia (CML), drug resistance remains a major obstacle. Studies on the mechanisms underlying imatinib resistance and other alternative drugs are urgently needed. Liquid chromatography tandem mass spectrometry was applied to investigate the differences in proteomics and phosphoproteomics between K562 and K562/G (imatinib resistant K562). Multiple bioinformatics analyses were performed to unveil the differential signal pathways. CCK-8 was used to detect cell proliferation. Flow cytometry was performed to analyze reactive oxygen species (ROS), cell cycle, and cell apoptosis. Western blotting and quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) were used to observe the changes of ROS and autophagy associated with imatinib resistance in CML. Our results indicated that ROS-autophagy formed one negative feedback loop and was associated with imatinib resistance. Additionally, the limited-rate enzymes of serine synthesis pathway were escalated in K562/G, which could contribute to the increased cyclin-dependent kinases and cell proliferation index. According to phosphoproteomics data, K562/G cells exhibited abnormal phosphorylation of splicing signals. These results revealed that it could be one useful strategy to correct metabolism shift and oxidative stress, or moderately regulate autophagy. Future research should focus on the discovery of potential targets in ROS-autophagy loop.

MicroRNA as a Novel Biomarker in the Diagnosis of Head and Neck Cancer

Head and neck squamous cell carcinoma is the sixth most common cancer worldwide, with 890,000 new cases and 450,000 deaths in 2018, and although the survival statistics for some patient groups are improving, there is still an urgent need to find a fast and reliable biomarker that allows early diagnosis. This niche can be filled by microRNA, small single-stranded non-coding RNA molecules, which are expressed in response to specific events in the body. This article presents the potential use of microRNAs in the diagnosis of HNSCC, compares the advances in this field to other diseases, especially other cancers, and discusses the detailed use of miRNA as a biomarker in profiling and predicting the treatment outcome with radiotherapy and immunotherapy. Potential problems and difficulties related to the development of this promising technology, and areas on which future research should be focused in order to overcome these difficulties, were also indicated.

miRNAs mediated drug resistance in hematological malignancies

Despite improvements in the therapeutic approaches for hematological malignancies in the last decades, refractory disease still occurs, and cancer drug resistance still remains a major hurdle in the clinical management of these cancer patients. The investigation of this problem has been extensive and different mechanism and molecules have been associated with drug resistance. MicroRNAs (miRNAs) have been described as having an important action in the emergence of cancer, including hematological tumors, and as being major players in their progression, aggressiveness and response to treatments. Moreover, miRNAs have been strongly associated with cancer drug resistance and with the modulation of the sensitivity of cancer cells to a wide array of anticancer drugs. Furthermore, this role has also been reported for miRNAs packaged into extracellular vesicles (EVs-miRNAs), which in turn have been described as essential for the horizontal transfer of drug resistance to sensitive cells. Several studies have been suggesting the use of miRNAs as biomarkers for drug response and clinical outcome prediction, as well as promising therapeutic tools in hematological diseases. Indeed, the combination of miRNA-based therapeutic tools with conventional drugs contributes to overcome drug resistance. This review addresses the role of miRNAs in the pathogenesis of hematological malignances, namely multiple myeloma, leukemias and lymphomas, highlighting their important action (either in their cell-free circulating form or within circulating EVs) in drug resistance and their potential clinical applications.

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.

Long Noncoding RNA SOCS2-AS Promotes Leukemogenesis in FLT3-ITD+ Acute Myeloid Leukemia Through miRNA-221

Background

LncRNAs play an important role in tumorigenesis and development in tumors, but the function of lncRNA SOCS2-AS in acute myeloid leukemia (AML) is unknown.

Materials and Methods

In the present study, we used RT-PCR to detect the expression of SOCS2-AS in FLT3-ITD+, FLT3-ITD- AML patients and different AML cell lines. The colony formation and CCK-8 assay were performed to analyze the proliferation ability, and the flow cytometry was performed to analyze the capacity of apoptosis in Molm-13 and MV4-11 cells. The Western blot was applied to detect the expression of STAT5 and p-STAT5. The RNA pull-down and luciferase activity were used to investigate the interaction between SOCS2-AS and miR-221.

Results

The results indicate that SOCS2-AS shows overexpression in FLT3-ITD+ AML patients compared to FLT3-ITD- AML patients. Si-SOCS2-AS can inhibit the proliferation, boost the apoptosis and induce the cycle arrest in Molm-13 cells, and SOCS2-AS overexpression promotes proliferation and colony formation in MV4-11 cells. The miR-221 shows overexpression in FLT3-ITD+ AML patients compared to FLT3-ITD- AML patients. And the expression level of miR-221 and SOCS2-AS shows negative correlation in FLT3-ITD+ AML patients. Functionally, SOCS2-AS could be interacted with miR-221 in AML cells. After SOCS2-AS knockdown, the phosphorylation level of STAT5 was significantly decreased. Moreover, miR-221 inhibitor can rescue the viability in cells after si-SOCS2-AS transfection. And it is stated that SOCS2-AS regulates the STAT5 signal transduction pathway with sponging miR-221.

Conclusion

In conclusion, this study confirms the molecular mechanism of SOCS2-AS in AML by targeting the miR-221/STAT5 signaling pathway. This indicates SOCS2-AS may serve as a potential therapeutic target for the treatment of AML.

Role of non-coding RNA networks in leukemia progression, metastasis and drug resistance

Early-stage detection of leukemia is a critical determinant for successful treatment of the disease and can increase the survival rate of leukemia patients. The factors limiting the current screening approaches to leukemia include low sensitivity and specificity, high costs, and a low participation rate. An approach based on novel and innovative biomarkers with high accuracy from peripheral blood offers a comfortable and appealing alternative to patients, potentially leading to a higher participation rate.

Recently, non-coding RNAs due to their involvement in vital oncogenic processes such as differentiation, proliferation, migration, angiogenesis and apoptosis have attracted much attention as potential diagnostic and prognostic biomarkers in leukemia. Emerging lines of evidence have shown that the mutational spectrum and dysregulated expression of non-coding RNA genes are closely associated with the development and progression of various cancers, including leukemia. In this review, we highlight the expression and functional roles of different types of non-coding RNAs in leukemia and discuss their potential clinical applications as diagnostic or prognostic biomarkers and therapeutic targets.

Insulin-like growth factor-binding proteins play a significant role in the molecular response to imatinib in chronic myeloid leukemia patients

Imatinib (IM) is successfully used in the majority of patients with chronic myeloid leukemia (CML), but some patients develop resistance to drug treatment. Insufficient apoptosis results in uncontrolled cell proliferation, which is closely associated with the occurrence of drug resistance. Therefore, it is crucial to identify new biomarkers related to drug resistance. This aim of the present study was to investigate the profile of apoptosis-related proteins in K562 and K562/G (IM-resistant K562 cells) cells, in order to identify new biomarkers. A human apoptosis antibody array was used to screen 46 proteins in the two cells lines, among which 20 proteins were found to be differentially expressed between K562 and K562/G cells. The major proteins included secreted caspase-8, insulin-like growth factor-binding protein (IGFBP)-1, IGFBP-2, IGFBP-3, caspase-3 and p27. IGFBP-1 IGFBP-2 and IGFBP-3 were selected for the follow-up study. Subsequently, reverse transcription-quantitative PCR analysis and western blotting were used to detect the expression levels of the IGFBPs. The results revealed that the expression levels of IGFBP-2 and IGFBP-3 in K562/G cells were significantly decreased compared with those in K562 cells, whereas the IGFBP-1 level was higher. Moreover, no significant correlation was observed between IGFBP-1 or IGFBP-2 and the level of the BCR-ABL fusion protein, whereas decreasing IGFBP-3 levels were associated with increasing BCR-ABL levels. These results suggested that IGFBP-1, IGFBP-2 and IGFBP-3 could be useful novel biomarkers for IM resistance in CML.

MiRNAs as Novel Adipokines: Obesity-Related Circulating MiRNAs Influence Chemosensitivity in Cancer Patients

Adipose tissue is an endocrine organ, capable of regulating distant physiological processes in other tissues via the release of adipokines into the bloodstream. Recently, circulating adipose-derived microRNAs (miRNAs) have been proposed as a novel class of adipokine, due to their capacity to regulate gene expression in tissues other than fat. Circulating levels of adipokines are known to be altered in obese individuals compared with typical weight individuals and are linked to poorer health outcomes. For example, obese individuals are known to be more prone to the development of some cancers, and less likely to achieve event-free survival following chemotherapy. The purpose of this review was twofold; first to identify circulating miRNAs which are reproducibly altered in obesity, and secondly to identify mechanisms by which these obesity-linked miRNAs might influence the sensitivity of tumors to treatment. We identified 8 candidate circulating miRNAs with altered levels in obese individuals (6 increased, 2 decreased). A second literature review was then performed to investigate if these candidates might have a role in mediating resistance to cancer treatment. All of the circulating miRNAs identified were capable of mediating responses to cancer treatment at the cellular level, and so this review provides novel insights which can be used by future studies which aim to improve obese patient outcomes.

Protective autophagy or autophagic death: effects of BEZ235 on chronic myelogenous leukemia

Purpose

To investigate the effects of BEZ235 on chronic myeloid leukemia (CML) cells.

Methods

MTS assay was used to detect the proliferation of CML cells. The proteins expression were detected by Western blot assay. The effects of BEZ235 on autophagy in CML cells were verified through transmission electron microscopy and evaluated by laser confocal microscopy. Annexin V-FITC/PI double staining flow cytometry was used to detect apoptosis. A xenograft model was established to observe the therapeutic effect of BEZ235 in vivo.

Results

BEZ235 could inhibit the proliferation of CML cells; CQ and 3-MA could increase the proliferation inhibition and Z-VAD-FMK can reduce the proliferation inhibition of BEZ235 on CML cells (P<0.05). Results of TEM showed that the autophagosomes of CML cells treated with BEZ235 increased (P<0.05). The results by confocal microscopy showed that the autophagic activity of K562 cells increased with BEZ235 treatment. When BEZ235 combined with CQ, BEZ235-induced autophagic flow was blocked. FCM results showed that BEZ235 could induces apoptosis in CML cells. Z-VAD-FMK could decrease the apoptosis of CML cells induced by BEZ235. CQ increased the apoptosis of CML cells induced by BEZ235 (P<0.05). Western blot showed that BEZ235 inhibited the phosphorylation of AKT and S6K. BEZ235 alone could upregulate the expression of cleaved caspase-3 and LC3II. When combined with Z-VAD-FMK, the expression of cleaved caspase-3 was lower than that of BEZ235 alone. When combined with CQ, the expression of cleaved caspase-3 and LC3II were higher than those of BEZ235 alone (P<0.05). BEZ235 could inhibit the growth of xenografts of CML cell line.

Conclusion

BEZ235 can inhibit the proliferation of CML cells, induce apoptosis, and enhance autophagy activity. It induces protective autophagy. The combination of CQ can enhance the apoptosis and proliferation inhibition of CML cells induced by BEZ235.