Proliferation Of Myeloid Leukemia Cells Research Articles

Bone Marrow Mesenchymal Stem Cells-Derived Exosomal miR-425-5p Inhibits Acute Myeloid Leukemia Cell Proliferation, Apoptosis, Invasion and Migration by Targeting WTAP.

IntroductionAcute myeloid leukemia (AML) is a predominant blood malignancy with high mortality and severe morbidity. AML is affected by microRNAs (miRNAs) loaded in exosomes derived from bone marrow mesenchymal stem cells (BM-MSCs). MiR-425-5p has been reported to participate in different cancer models. However, the function of BM-MSCs-derived exosomal miR-425-5p in AML is unclear.MethodsThe expression of miR-425-5p was measured by qRT-PCR in clinical AML samples. The immunophenotype of BM-MSCs was analyzed using antibodies against CD44, CD90, and CD105. The exosome was isolated from BM-MSCs. The effect of BM-MSCs-derived exosomal miR-425-5p on AML was analyzed by CCK-8 assay, Edu assay, transwell assay, flow cytometry in AML cells. qRT-PCR, luciferase reporter gene assay and Western blot analysis were also conducted in AML cells.ResultsThe expression levels of miR-425-5p were decreased in CD34 + CD38-AML cells from primary AML patients compared to that from the bone marrow of healthy cases, and were reduced in exosomes from AML patients compared that from healthy cases. Similarly, miR-425-5p was also down-regulated in AML cell lines compared with BM-MSCs. MiR-425-5p was able to express in exosomes from BM-MSCs. CCK-8, Edu, transwell assay and flow cytometry analysis revealed that BM-MSCs-derived exosomal miR-425-5p significantly inhibited cell viability, Edu positive cells, invasion and migration, and induced apoptosis of AML cells. Meanwhile, the expression levels of cleaved PARP and cleaved caspase3 were increased by BM-MSCs-derived exosomal miR-425-5p in cells. MiR-425-5p inhibited the expression of Wilms tumor 1-associated protein (WTAP). Moreover, overexpression of WTAP could reverse the miR-425-5p-induced inhibition effect on AML cell proliferation, apoptosis, migration and invasion.ConclusionBM-MSCs-derived exosomal miR-425-5p inhibits proliferation, invasion and migration of AML cells and induced apoptosis of AML cells by targeting WTAP. Therapeutically, BM-MSCs-derived exosomal miR-425-5p may serve as a potential target for AML therapy.

RanBP3 Regulates Proliferation, Apoptosis and Chemosensitivity of Chronic Myeloid Leukemia Cells via Mediating SMAD2/3 and ERK1/2 Nuclear Transport.

Abnormal subcellular localization of proteins is an important cause of tumorigenesis and drug resistance. Chromosome region maintenance 1 (CRM1), the nuclear export regulator of most proteins, has been confirmed to be over-expressed in various malignancies and is regarded as an efficient target. But the potential role of the CRM1 cofactor RanBP3 (Ran Binding Protein 3) is left unrevealed in chronic myeloid leukemia (CML). Here, we first detected the level of RanBP3 in CML and found an elevated RanBP3 expression in CML compared with control. Then we used shRNA lentivirus to down-regulated RanBP3 in imatinib sensitive K562 cells and resistant K562/G01 cells and found RanBP3 silencing inhibited cell proliferation by up-regulating p21, induced caspase3-related cell apoptosis, and enhanced the drug sensitivity of IM in vitro. Notably, we observed that RanBP3 silencing restored imatinib sensitivity of K562 cells in NOD/SCID mice. Mechanistically, the nuclear aggregation of SMAD2/3 revealed that tumor suppressor axis (TGF-β)-SMAD2/3-p21 was the anti-proliferation program related to RanBP3 knockdown, and the decrease of cytoplasmic ERK1/2 caused by RanBP3 interference leaded to the down-regulation of anti-apoptosis protein p(Ser112)-BAD, which was the mechanism of increased cell apoptosis and enhanced chemosensitivity to imatinib in CML. In summary, this study revealed the expression and potential role of RanBP3 in CML, suggesting that targeting RanBP3 alone or combined with TKIs could improve the clinical response of CML.

Myeloid-Derived Suppressor Cells and Mesenchymal Stem/Stromal Cells in Myeloid Malignancies.

Myeloid malignancies arise from an altered hematopoietic stem cell and mainly comprise acute myeloid leukemia, myelodysplastic syndromes, myeloproliferative malignancies, and chronic myelomonocytic leukemia. Myeloid neoplastic leukemic cells may influence the growth and differentiation of other hematopoietic cell lineages in peripheral blood and bone marrow. Myeloid-derived suppressor cells (MDSCs) and mesenchymal stromal cells (MSCs) display immunoregulatory properties by controlling the innate and adaptive immune systems that may induce a tolerant and supportive microenvironment for neoplasm development. This review analyzes the main features of MDSCs and MSCs in myeloid malignancies. The number of MDSCs is elevated in myeloid malignancies exhibiting high immunosuppressive capacities, whereas MSCs, in addition to their immunosuppression contribution, regulate myeloid leukemia cell proliferation, apoptosis, and chemotherapy resistance. Moreover, MSCs may promote MDSC expansion, which may mutually contribute to the creation of an immuno-tolerant neoplasm microenvironment. Understanding the implication of MDSCs and MSCs in myeloid malignancies may favor their potential use in immunotherapeutic strategies.

Targeting FEN1 Suppresses the Proliferation of Chronic Myeloid Leukemia Cells Through Regulating Alternative End-Joining Pathways.

Chronic myeloid leukemia (CML) is characterized by the formation of the BCR-ABL fusion gene. The BCR-ABL protein leads to an increased level of reactive oxygen species, which is a major cause of endogenous DNA double-strand breaks (DSBs). CML cells are prone to rely on a highly mutagenic alternative end-joining (Alt-EJ) pathway to cope with enhanced DSBs, which aggravates chromosomal instability. Hence, targeting dysregulated DNA repair proteins provides new insights into cancer treatment. In this study, we discovered the abnormal upregulation of Flap endonuclease 1 (FEN1) in CML, as well as FEN1's participation in the error-prone Alt-EJ repair pathway and its interplay with DNA Ligase1 and proliferating cell nuclear antigen in DSB repair. Knockdown of FEN1 by shRNA not only inhibited the proliferation and induced apoptosis but also enhanced the efficacy of imatinib (IM) in drug-resistant CML cell K562/G01. Moreover, excessive DSB accumulation was detected after FEN1 inhibition. In summary, our results demonstrated that FEN1 is a promising therapeutic target in CML treatment. This work extends the understanding of regulating abnormal DSB repair for cancer treatment.

Positive interactions between STAP-1 and BCR-ABL influence chronic myeloid leukemia cell proliferation and survival

Chronic myeloid leukemia (CML) is a clonal disease characterized by the presence of the Philadelphia chromosome and its oncogenic product, BCR-ABL, which activates multiple pathways involved in cell survival, growth promotion, and disease progression. We recently reported that signal-transducing adaptor protein 1 (STAP-1) is upregulated in CML stem cells (LSCs) and functions to reduce the apoptosis of CML LSCs by upregulating the STAT5-downstream anti-apoptotic genes. In this study, we demonstrate the detailed molecular interactions among BCR-ABL, STAP-1, and signal transducer and activator of transcription 5 (STAT5). Studies with deletion mutants have revealed that STAP-1 interacts with BCR-ABL and STAT5a through its SH2 and PH domains, respectively, suggesting the possible role of STAP-1 as a scaffold protein. Furthermore, the binding of STAP-1 to BCR-ABL stabilizes the BCR-ABL protein in CML cells. Since STAP-1 is highly expressed in CML cells, we also analyzed the STAP-1 promoter activity using a luciferase reporter construct and found that NFATc1 is involved in activating the STAP-1 promoter and inducing STAP-1 mRNA expression. Our results demonstrate that STAP-1 contributes to the BCR-ABL/STAT5 and BCR-ABL/Ca2+/NFAT signals to induce proliferation and STAP-1 mRNA expression in CML cells, respectively.

Exosomes from BM-MSCs promote acute myeloid leukemia cell proliferation, invasion and chemoresistance via upregulation of S100A4

BackgroundBM-MSCs play an important role in cancer development through the release of cytokines or exosomes. Studies have shown that extracellular exosomes derived from BM-MSCs are a key pro-invasive factor. However, how BM-MSC-exos influence AML cell proliferation, invasion and chemoresistance remains poorly understood.MethodsWe isolated exosomes from BM-MSCs and used electron microscopy, particle size separation and western blots to identify the exosomes. The invasion of leukemia cells was observed with a transwell assay. The stemness traits and chemoresistance of the leukemia cells were detected by FCM, colony formation and CCK-8 assays. TCGA database was used to investigate the prognostic relevance of S100A4 and its potential role in AML.ResultsIn this study, we found that BM-MSC-exos increased the metastatic potential, maintained the stemness and contributed to the chemoresistance of leukemia cells. Mechanistically, BM-MSC-exos promoted the proliferation, invasion and chemoresistance of leukemia cells via upregulation of S100A4. Downregulating S100A4 clearly suppressed the proliferation, invasion, and chemoresistance of leukemia cells after treatment with BM-MSC-exos. Bioinformatic analysis with data in TCGA database showed that S100A4 was associated with poor prognosis in AML patients, and functional enrichment revealed its involvement in the processes of cell–cell adhesion and cytokine regulation.ConclusionsS100A4 is vital in the BM-MSC-exo-driven proliferation, invasion and chemoresistance of leukemia cells and may serve as a potential target for leukemia therapy.

YBX1 is required for maintaining myeloid leukemia cell survival by regulating BCL2 stability in an m6A-dependent manner

AbstractRNA-binding proteins (RBPs) are critical regulators of transcription and translation that are often dysregulated in cancer. Although RBPs are increasingly recognized as being important for normal hematopoiesis and for hematologic malignancies as oncogenes or tumor suppressors, RBPs that are essential for the maintenance and survival of leukemia remain elusive. Here we show that YBX1 is specifically required for maintaining myeloid leukemia cell survival in an N6-methyladenosine (m6A)-dependent manner. We found that expression of YBX1 is significantly upregulated in myeloid leukemia cells, and deletion of YBX1 dramatically induces apoptosis and promotes differentiation coupled with reduced proliferation and impaired leukemic capacity of primary human and mouse acute myeloid leukemia cells in vitro and in vivo. Loss of YBX1 has no obvious effect on normal hematopoiesis. Mechanistically, YBX1 interacts with insulin-like growth factor 2 messenger RNA (mRNA)-binding proteins (IGF2BPs) and stabilizes m6A-tagged RNA. Moreover, YBX1 deficiency dysregulates the expression of apoptosis-related genes and promotes mRNA decay of MYC and BCL2 in an m6A-dependent manner, which contributes to the defective survival that results from deletion of YBX1. Thus, our findings have uncovered a selective and critical role of YBX1 in maintaining myeloid leukemia survival, which might provide a rationale for the therapeutic targeting of YBX1 in myeloid leukemia.

Structure-Based Identification of Potent Lysine-Specific Demethylase 1 Inhibitor Peptides and Temporary Cyclization to Enhance Proteolytic Stability and Cell Growth-Inhibitory Activity.

Peptides are attractive drug candidates, but their utility is greatly limited by their inherent susceptibility to proteolytic degradation and their inability to pass through the cell membrane. Here, we employ a strategy of temporary cyclization to develop a cell-active lysine-specific demethylase 1 (LSD1/KDM1A) inhibitor peptide. We first identified a highly potent LSD1-inhibitory linear peptide, with the assistance of X-ray crystal structure data of inhibitor peptide-bound LSD1·CoREST. The peptide was converted to a redox-activatable cyclic peptide incorporating cell-penetrating peptide (CPP), expecting selective activation under intracellular reducing conditions. The cyclic peptide moiety exhibited enhanced stability to protease and was converted to the linear, unmodified LSD1 inhibitor peptide under reducing conditions. The cyclic peptide with CPP inhibited the proliferation of human acute myeloid leukemia cells (HL-60) in the low micromolar concentration range.

Small-sized extracellular vesicles (EVs) derived from acute myeloid leukemia bone marrow mesenchymal stem cells transfer miR-26a-5p to promote acute myeloid leukemia cell proliferation, migration, and invasion.

Bone marrow mesenchymal stem cells (BMSCs) in acute myeloid leukemia (AML) microenvironment undergo modification that includes expression of contents in the small-sized extracellular vesicles (EVs) they secrete. This study aims to investigate whether small-sized EVs from BMSCs of AML patients regulate AML progression by modifying the expression of miR-26a-5p. Small-sized EVs from BMSCs of AML patients (AML-BMSC-EVs) or healthy controls (HC-BMSC-EVs) were isolated by ultra-centrifugation and administered to AML cells (OCI/AML-2 and THP-1). Cell proliferation, migration, and invasion were evaluated by CCK-8 assay, Transwell migration and invasion assays, respectively. Compared with HC-BMSC-EVs, AML-BMSC-EVs contained higher expression of miR-26a-5p and promoted AML cell proliferation, migration, and invasion. Inhibition of miR-26a-5p expression in AML-BMSC-EVs could abrogate the promoting effects of AML-BMSC-EVs on AML cell proliferation, migration, and invasion. Furthermore, GSK3β was a direct target of miR-26a-5p. Moreover, AML-BMSC-EVs inhibited GSK3β expression and activated Wnt/β-catenin signaling in AML cells. Additionally, GSK3β overexpression in THP-1 cells counteracted the promoting effects of AML-BMSCs-EVs on THP-1 cell proliferation, migration, and invasion. AML-BMSC-EVs promoted AML progression by transferring miR-26a-5p to AML cells and subsequently activating the Wnt/β-catenin pathway.

LncRNA-SNHG16 promotes proliferation and migration of acute myeloid leukemia cells via PTEN/PI3K/AKT axis through suppressing CELF2 protein

The silence of lncRNA small nucleolar RNA host gene 16 (SNHG16) suppressed acute lymphoblastic leukemia (ALL) cell proliferation and migration, whereas its role in acute myeloid leukemia (AML) still lacks clarity. This study showed that SNHG16 was upregulated in AML patients and cells. And SNHG16 overexpression remarkably enhanced the proliferation and migration capacities of HL60 and AML-193 cells, while SNHG16 knockdown acted the opposite way. Subsequently, we revealed that SNHG16 directly bound to CELF2 (CUGBP Elav-like family member 2) protein, and caused CELF2 mRNA unstably and proteins reducing. CELF2 was decreased both in AML patients and cells. CELF2 overexpression or interference weakened the effect of overexpressing or silencing SNHG16 on proliferation and migration. Moreover, the transfection of pcDNA-CELF2 elevated PTEN (phosphatase and tensin homolog) activity and hindered the phosphoinositide 3-kinase (PI3K)/AKT signaling. And SNHG16 reduced PTEN activity and promoted the PI3K/AKT pathway activation by restraining CELF2. Furthermore, GDC-0941 (a specific inhibitor of the PI3K/AKT pathway) impeded the effect of SNHG16 increase, and bpV(pic) (a specific PTEN inhibitor) declined the effect of SNHG16 decrease on cell proliferation and migration. Taken together, the present study indicated that SNHG16 promoted proliferation and migration of AML cells via PTEN/PI3K/AKT axis through suppressing CELF2 protein.

LINC01255 combined with BMI1 to regulate human mesenchymal stromal senescence and acute myeloid leukemia cell proliferation through repressing transcription of MCP-1.

Long non-coding RNAs (lncRNAs) govern fundamental biochemical and cellular biology processes, for example, participate in chromatin remodeling, imprinting, splicing, transcriptional regulation and translation. Dysregulation of lncRNA expression is act as a feature of various diseases and cancers, including hematopoietic malignancies. However, the clinical relevance of myelodysplastic syndrome (MDS) and acute myeloid leukemia preceded by MDS (MDS-AML) requires further research. Recently, lncRNAs have been demonstrated, which play an important role in hematopoiesis, thus, to further finding more functional lncRNA seemed particularly important. Western blotting, real-time PCR, RNA-pulldown, RIP (RNA immunoprecipitation), Chromatin immunoprecipitation (ChIP), cellular compartments extraction assays, SA-β-gal staining, lentivirus transfection, cell viability assay and cell proliferation assays were used to examine the relationship between lncRNA LINC01255 and its regulation of p53-p21 pathway in human mesenchymal stromal and acute myeloid leukemia cells. LncRNA LINC01255 is highly expressed in bone marrow cells of AML patients, CD34+ cells of MDS-AML patients and AML cell lines and the higher expression of LINC01255 is associated with poor survival rate of AML patients. LINC01255 can interact with BMI1 and repress the transcription of MCP-1 to active p53-p21 pathway, thus inhibiting the senescence of human mesenchymal stromal and proliferation of acute myeloid leukemia cell. We discovered a novel functional lncRNA LINC01255, which can regulate the senescence of human mesenchymal stromal and the proliferation of acute myeloid leukemia cell through inhibiting the transcription of MCP-1.

RETRACTED: LncRNA CCDC26 Interacts with CELF2 Protein to Enhance Myeloid Leukemia Cell Proliferation and Invasion via the circRNA_ANKIB1/miR-195-5p/PRR11 Axis

LncRNA CCDC26 is aberrantly expressed in myeloid leukemia (ML) and promotes myeloid leukemia progression, but the potential mechanism of CCDC26 in regulating ML progression is unclear. In this study, we observed that lncRNA CCDC26 was upregulated in both chronic and acute ML cell lines. LncRNA CCDC26 promoted the proliferation and invasion of K562 and HL-60 cells, which was determined by cell counting kit-8 test and Transwell invasion assay. Flow cytometry showed that lncRNA CCDC26 inhibited cell apoptosis. Bioinformatics and expression correlation analyses revealed that there was a potential interaction between CCDC26 and CUGBP Elav-like family member 2 (CELF2) protein, an RNA bind protein (RBP). Then the relationship between CCDC26 and the RBP CELF2 was identified by using RNA pull-down and RNA immunoprecipitation (RNA-IP) assays. Further analysis showed that overexpression of CCDC26 could noticeably upregulate circRNA_ANKIB1 expression via sponging CELF2. Subsequently, we found that overexpressed circRNA_ANKIB1 could significantly promote proline rich 11 (PRR11) protein expression by sponging miR-195a-5p. Moreover, PRR11 was also upregulated by CCDC26 and downregulated by CELF2. Mechanically, we uncovered that the miR-195a-5p inhibitor activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways through upregulating PRR11 protein expression. Furthermore, the inhibitors of AKT, p65-NF-κB, or Bcl-2 could inhibit the effect of the miR-195a-5p inhibitor on ML cell behaviors. In conclusion, lncRNA CCDC26 could upregulate PRR11 protein expression by sponging miR-195a-5p, thereby activating the PI3K/AKT and NF-κB pathways to enhance ML cell proliferation and invasion and suppress cell apoptosis.

Circular RNA circCRKL inhibits the proliferation of acute myeloid leukemia cells via the miR-196a-5p/miR-196b-5p/p27 axis

ABSTRACT As a new type of non-coding RNA, the role of circular RNA (circRNA) in various diseases and tumors has received considerable attention. Studies have shown that circRNAs play an important role in the progression of acute myeloid leukemia (AML) via different mechanisms. However, the specific underlying molecular mechanism of circRNAs in the proliferation of AML cells remians unclear. This study aimed to clarify the biological role and mechanism of circCRKL in AML. The results indicated low circCRKL expression in AML cell lines and samples. Moreover, the overexpression of circCRKL inhibited the proliferation and colony-forming ability of AML cells, while its silencing promoted them. In addition, bioinformatics tools and luciferase assays revealed that circCRKL could sponge miR-196a-5p and miR-196b-5p to promote the expression of p27. Furthermore, circCRKL inhibited AML cell proliferation via the miR-196a-5p/miR-196b-5p/p27 axis, suggesting a potential new target for AML therapy.

Inhibitory effect of PI3Kδ inhibitor idelalisib on proliferation of human myeloid leukemia cells and the reversal effect on drug resistance to adriamycin.

To investigate the effect of adriamycin (ADM), idelalisib or ADM and their combination on cell proliferation and intracellular concentration of ADM, and to explore the reversal effect of idelalisib on drug resistance to ADM. The K562 and K562/ADM cells were respectively treated with ADM and idelalisib at different concentrations. The 50% inhibitory concentration (IC50) and drug resistance index (RI) of ADM to the 2 kinds of cells were measured by methyl thiazolyl tetrazolium (MTT) assay. Non-cytotoxic dose (cell inhibition rate <5%) of idelalisib in the 2 kinds of cells was determined. Then the K562 and k562/ADM cells were divided into the following groups: a K562 cells + ADM group, a K562 cells + ADM + idelalisib group, a K562/ADM cells + ADM group, and a K562/ADM cells + ADM + idelalisib group. The survival rates, the intracellular ATP levels, and the relative concentration of intracellular ADM were detected by MTT method, ATP bioluminescence assay (ATP-BLA) and flow cytometry (FCM), respectively. The cell survival rates were significantly decreased in a dose-dependent manner when the cells were treated with different doses of ADM (0.001-10.000 mg/L ). The IC50 value of ADM in the K562 and K562/ADM cells were 0.2 mg/L and 1.0 mg/L, respectively. The RI value was 5. The cell survival rates were also significantly decreased in a dose-dependent manner when the cells were treated with different doses of idelalisib (1-50 μmol/L). The non-cytotoxic dose of idelalisib in the K562 and K562/ADM cells were 25 μmol/L and 15 μmol/L, respectively. The cell survival rates in the ADM+ idelalisib group was less than that in the ADM group (P<0.05)；while there was no statistical difference between the ADM+ idelalisib group and the ADM group in the K562 cells (P>0.05). The intracellular ATP level in the K562 cells was about (91.502±0.479) mmol/L, and that in the K562/ADM cells was about (24.311±0.349) mmol/L. The intracellular ATP level in the ADM+ idelalisib group in the K562/ADM cells was less than that in the ADM group (P<0.05); but there was no statistical difference between the ADM + idelalisib group and the ADM group in the K562 cells (P>0.05). The absorption of intracellular ADM in the ADM + idelalisib group in the K562/ADM cells was more than that in the ADM group (P<0.05); but there was no statistical difference in the K562 cells between the 2 groups (P>0.05). The exclusion of intracellular ADM in the ADM + idelalisib group in the K562/ADM cells was less than that in the ADM group (P<0.05 or P<0.01)；but there was no statistical difference in the K562 cells between the 2 groups (P>0.05). Idelalisib exerts effect on inhibition of the proliferation in myeloid leukemia K562 and K562/ADM cells, which may partially reverse the drug resistance of K562/ADM cells to ADM. The mechanisms for the effect of idelalisib may be related to increasing the accumulation of ADM and inducing the cell apoptosis in the K562 and K562/ADM cells.

MicroRNAs of bone marrow mesenchymal stem cell-derived exosomes regulate acute myeloid leukemia cell proliferation and apoptosis.

Acute myeloid leukemia (AML) is a malignant hematological disease, originating from hematopoiesis stem cell differentiation obstruction and clonal proliferation. New reagents or biologicals for the treatment of AML are urgently needed, and exosomes have been identified as candidate biomarkers for disease diagnosis and prognosis. This study aimed to investigate the effects of exosomes from bone marrow mesenchymal stem cells (BMSCs) on AML cells as well as the underlying microRNA (miRNA)-mediated mechanisms. Exosomes were isolated using a precipitation method, followed by validation using marker protein expression and nanoparticle tracking analysis. Differentially expressed miRNAs were identified by deep RNA sequencing and confirmed by quantitative real-time polymerase chain reaction (qPCR). Cell proliferation was assessed by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt method, and cell cycle progression and apoptosis were detected by flow cytometry. Functional gene expression was analyzed by qPCR and Western blotting (WB). Significant differences were determined using Student's t test or analysis of variance. BMSCs-derived exosomes effectively suppressed cell proliferation (both P < 0.0001 at 10 and 20 μg/mL) and cell cycle progression (P < 0.01 at G0-G1 stage), and also significantly enhanced cell apoptosis (P < 0.001) in KG-1a cells. There were 1167 differentially expressed miRNAs obtained from BMSCs-derived exosomes compared with KG-1a cell-derived exosomes (P < 0.05). Knockdown of hsa-miR-124-5p in BMSCs abrogated the effects of BMSCs-derived exosomes in regulating KG-1a such as the change in cell proliferation (both P < 0.0001 vs. normal KG-1a cell [NC] at 48 and 72 h). KG-1a cells treated with BMSCs-derived exosomes suppressed expression of structural maintenance of chromosomes 4 (P < 0.001 vs. NC by qPCR and P < 0.0001 vs. NC by WB), which is associated with the progression of various cancers. This BMSCs-derived exosomes effect was significantly reversed with knockdown of hsa-miR-124-5p (P < 0.0001 vs. NC by WB). BMSCs-derived exosomes suppress cell proliferation and cycle progression and promote cell apoptosis in KG-1a cells, likely acting through hsa-miR-124-5p. Our study establishes a basis for a BMSCs-derived exosomes-based AML treatment.

Effect of GÖ6976 on Proliferation of Chronic Myeloid Leukemia Cells and Its Toxicity on Normal Cells and Mice

To investigate the effect of GÖ6976 on the proliferation of chronic myeloid leukemia cells and its toxic effect on normal cells and mice, so as to provide experimental basis for the effectiveness and safety of its clinical application. Different concentrations of GÖ6976 were applied to the K562 cells, human peripheral blood mononuclear cells (PBMNC) and normal BaF3 cells, MTT assay was used to detect the effect on cell proliferation. BALB/C mice were used to investigate the toxicity in vivo. The general situation, body weight and the number of white blood cells in peripheral blood were monitored during administration, the blood collected from eyeballs before and after administration was used for biochemical examination, at the same time, the liver, kidney and femurs were examined pathologically. GÖ6976 could significantly inhibit the proliferation of K562 cells, inhibition effect increased with increasing dose (r=0.9623). However, there was no significant change in the inhibitory effect on PBMNC and BaF3 cells. The pathological examination of organs in each group showed no abnormal manifestations such as inflammatory infiltration, while the change rate of leukocyte count in peripheral blood of high dose group fluctuated greatly (P＜0.05), which might be related to the inhibition of intracellular protein kinase C, and no abnormality was observed in blood biochemical indexes. In the low dose group, there was no significant difference in peripheral blood leukocyte count, blood biochemical index and histopathology during administration drug as compared with the control group. GÖ6976 possesses a significant inhibitory effect on the proliferation of K562 cells, and the inhibitory effect increases with increasing dose. Long-term application of 5.0 μmol/L and below concentrations of GÖ6976 shows no obvious inhibitory effect on PBMNC, BaF3 cells. Long-term application of 10 mg/kg and below concentrations of GÖ6976 shows no obvious toxic effect on BALB/c mice.

Effect of MiR-29b-3p Targeting STAT3 on Proliferation and Apoptosis of Acute Myeloid Leukemia Cells

To investigate the effect of miR-29b-3p on apoptosis and proliferation of acute myeloid leukemia (AML) cells by targeting signal transducer and activator of transcription 3 (STAT3). TargetScan and miRanda online databases were used to predict the binding sites of miR-29b-3p and STAT3 3'UTR. The targeting relationship between them was estimated by Dual-Luciferase reporter assay experiment. After miR-29b-3p over-expression, qPCR and Western blot were used to detect the expression of STAT3 mRNA and proteins, flow cytometry to determine the apoptosis of AML cells, and MTS to detect the changes of cell proliferation in each group. Dual-Luciferase reporter assay confirmed that STAT3 was the target gene of miR-29b-3p. After miR-29b-3p overexpression, the expression of STAT3 mRNA and protein decreased. Compared with the control groups, the proliferation of AML cells in the overexpression group decreased and the apoptosis increased (P<0.05). MiR-29b-3p can inhibit the proliferation and induce apoptosis of AML cells by down-regulating STAT3.

Inhibitory Effects of Agaricus Blazei Murrill (FA-2-b-β) on Proliferation of Chronic Myeloid Leukemia Cells in vivo and Its Mechanism

To investigated the anti-tumor in vivo effect and mechanism of the acid RNA protein complex (FA-2-b-β) of Agaricus blazei Murrill extract. CCK-8 method was used to detected the inhibitory effect of FA-2-b-β on proliferation of primary CML cells from newly diagnosed CML patients, the CML mouse model was established by trail-venous injection of primary CML cells, and the survival time, blood cell count and body weight were observed, the immunoflouresence and immunehistochemistry analysis, RT-qPCR, Western bolt were used to detemine the expression of caspase-3 signal pathway-related apoptosis genes and proteins. The experiments in vitro showed that the proliferative inhibitory rate in drug-treated group increased with concentration- and time-dependent manner (r24=0.9092, r48=0.9442, r72=0.9546), the inter group comparison showed the statistical difference of results. The experiments in vitro showed that the survival time prolonged, blood cell count increased and body weight recovered in FA-2-b-β-treated group and imatinib-treated group, despite the WBC count is still high. The RT-qPCR and Western blot showed that the expression of BAX and caspase-3 gene and protein were up-regulated, the expression of BCL-2, cytochroime C, caspase-8, caspase-9 and BCL-ABL gene and protein were down-regulated. The FA-2-b-β can induce apoptosis of primary CML cells and prolong the survival time of CML model mouse, which may be related with the caspase-3 signal pathway related genes and proteins.

MiR-4792 Inhibits Acute Myeloid Leukemia Cell Proliferation and Invasion and Promotes Cell Apoptosis by Targeting Kindlin-3.

It has been reported that kindlin-3 expression is closely associated with progression of many cancers and microRNA (miRNA) processing. However, the effects and precise mechanisms of kindlin-3 in acute myeloid leukemia (AML) have not been well clarified. Our study aimed to explore the interaction between kindlin-3 and miR-4792 in AML. In our study, we found that the expression of kindlin-3 was dramatically increased in AML samples and cell lines, and the miR-4792 level was significantly downregulated. Interestingly, the low miR-4792 level was closely associated with upregulated kindlin-3 expression in AML samples. Moreover, introduction of miR-4792 dramatically suppressed proliferation and invasion and induced apoptosis of AML cells. We demonstrated that miR-4792 could directly target kindlin-3 by using both bioinformatics analysis and luciferase reporter assay. In addition, kindlin-3 silencing had similar effects with miR-4792 overexpression on AML cells. Overexpression of kindlin-3 in AML cells partially reversed the inhibitory effects of miR-4792 mimic. miR-4792 inhibited cell proliferation and invasion and induced apoptosis of AML cells by directly downregulating kindlin-3 expression, and miR-4792 targeting kindlin-3 was responsible for the regulation of the proliferation, invasion, and apoptosis of AML cells.

Long Non-Coding RNA Taurine Upregulated Gene 1 Targets miR-185 to Regulate Cell Proliferation and Glycolysis in Acute Myeloid Leukemia Cells in vitro.

BackgroundAcute myeloid leukemia (AML) is a group of malignant hematopoietic system diseases. Taurine-upregulated gene 1 (TUG1) is a long non-coding RNA that has been associated with human cancers, including AML. However, the role and molecular mechanisms of TUG1 in AML remains to be defined.MethodsExpression of TUG1 and miR-185 was detected using RT-qPCR. Cell viability and apoptotic rate were measured by MTT assay and flow cytometry, respectively. Glycolysis was determined by commercial glucose and lactate assay kits and Western blot. The target binding between TUG1 and miR-185 was predicted on Starbase online database and confirmed by luciferase reporter assay and RNA immunoprecipitation.ResultsTUG1 was upregulated and miR-185 was downregulated in the peripheral blood mononuclear cells of AML specimens and cells (HL-60, KG-1, MOLM-14, and MOLM-13). Both TUG1 knockdown and miR-185 overexpression via transfection could suppress cell viability, glucose consumption, lactate production, and hexokinase 2 expression, but promote apoptotic rate in HL-60 and KG-1 cells. Notably, TUG1 functioned as a sponge of miR-185 by target binding. Moreover, downregulation of miR-185 could partially overturn the effect of TUG1 knockdown on cell proliferation and glycolysis in HL-60 and KG-1 cells.ConclusionExpression of TUG1 was upregulated in AML patients and cells, and its knockdown repressed cell proliferation and glycolysis in AML cells in vitro by targeting miR-185.