Extracellular vesicle-mediated regulation of imatinib resistance in chronic myeloid leukemia via the miR-629-5p/SENP2/PI3K/AKT/mTOR axis.

BACKGROUND: Imatinib (IM) is the primary treatment for patients with chronic-phase CML (CML-CP). However, an increasing number of CML-CP patients have developed resistance to IM. Our study aims to explore the expression of miR-629-5p in extracellular vesicles (EVs) from both IM-sensitive (K562) and resistant (K562-Re) CML cell lines and to investigate the impact of regulating miR-629-5p expression on the biological characteristics of K562 and K562-Re cells. METHODS: Assess miR-629-5p expression levels in IM-sensitive and resistant CML cell lines. Separate EVs and verify it. EVs from K562-Re cells were co-cultured with K562 cells to detect the expression level of miR-629-5p. Target genes of miR-629-5p were determined and validated through luciferase experiments. Examined by manipulating miR-629-5p expression in cells using transfection techniques. The expression level of phosphorylated proteins in the PI3K/AKT/mTOR signaling pathway after IM was detected in CML cell lines. In K562-Re cells, the expression level of phosphorylated protein in the PI3K/AKT/mTOR signaling pathway was detected after single transfection of miR-629-5p inhibitor and cotransfection of miR-629-5p inhibitor and siSENP2. RESULTS: Increasing concentrations of EVs from K562-Re cells elevated miR-629-5p expression levels. The expression levels of miR-629-5p in CML cells varied with IM concentration and influenced the biological characteristics of cells. SENP2 was identified as a target gene of miR-629-5p. Furthermore, miR-629-5p was found to modulate the SENP2/PI3K/AKT/mTOR pathway, impacting IM resistance in CML cells. CONCLUSION: EVs from IM-resistant CML cells alter the expression of miR-629-5p in sensitive cells, activating the SENP2/PI3K/AKT/mTOR pathway and leading to IM resistance.

[Clinical Effect of Tyrosine Kinase Inhibitors in the Treatment of P230 Chronic Myeloid Leukemia].

OBJECTIVE: To observe the curative efficacy of tyrosine kinase inhibitors (TKIs) in the treatment of e19a2 transcript (P230) CML chronic phase (CML-CP) patients. METHODS: The clinical data of 11 P230 CML-CP patients were collected from July 2008 to December 2019. Blood routine examination, bone marrow cytology, chromosome, and BCR-ABL qualitative and quantitative tests were performed at initial diagnosis. After TKIs treatment, BCR-ABL (P230)/ABL in peripheral blood was regularly detected to evaluate molecular response by real-time quantitative PCR. RESULTS: There were 11 patients (7 males and 4 females) in chronic phase from 6 domestic hospitals enrolled, their median age was 46 years old (range from 19 to 56 years old). Among 4 patients treated with imatinib (400 mg, qd) firstly, 3 cases switched to nilotinib (400 mg, bid) and 1 case switched to dasatinib (100 mg, qd) due to failure to achieve best molecular response at the landmark time or mutation of ABL kinase. Then major molecular response (MMR) was obtained within 1 year. In addition, 5 patients were treated with nilotinib (300 mg, bid) and 2 patients with dasatinib (100 mg, qd) as first-line treatment, all of them got MMR within 6 months. CONCLUSION: For intolerance or resistance to imatinib, second-generation TKIs can enable P230 CML patients to achieve deeper molecular response, and MMR in a short time.

miR-621 May Suppress Cell Proliferation via Targeting lncRNA SNHG10 in Acute Myeloid Leukemia.

BACKGROUND: It has been reported that lncRNA SNHG10 (SNHG10) promotes the progression of liver cancer and osteosarcoma; however, the role of SNHG10 in acute myeloid leukemia (AML) remains unknown. This study was to explore the role of SNHG10 in AML. METHODS: The expression of SNHG10 and miR-621 in BM mononuclear cells (BMMNCs) isolated from 60 AML patients and 60 healthy controls were determined by RT-qPCR. Correlation between SNHG10 and miR-621 was analyzed by Pearson correlation coefficient. The overexpression of SNHG10 and miR-621 in transfected AML cells was detected by RT-qPCR, and the regulatory relationship between them was explored. Methylation-specific PCR (MSP) was applied to detect the methylation of miR-621 induced by the overexpression of SNHG10. CCK-8 assay was conducted to evaluate cell proliferation. RESULTS: In this study, we found that the expression of SNHG10 was upregulated and the expression of miR-621 was downregulated in AML samples. Moreover, SNHG10 and miR-621 were inversely correlated across AML samples, and a high level of SNHG10 predicted poor survival of AML patients. Bioinformatics analysis showed that SNHG10 could be targeted by miR-621. In AML cells, miR-621 overexpression downregulated the expression of SNHG10, while SNHG10 overexpression could not affect the expression of miR-621. However, it was found that the reduction of miR-621 caused by SNHG10 overexpression might be due to the increase of miR-621 methylation. In addition, SNHG10 overexpression significantly promoted BMMNC proliferation, whereas miR-621 overexpression inhibited BMMNC proliferation and abolished the effect of SNHG10 overexpression on BMMNC proliferation. CONCLUSION: miR-621 targets SNHG10 to suppress cell proliferation in AML.

LncRNA VPS9D1-AS1 promotes cell proliferation in acute lymphoblastic leukemia through modulating GPX1 expression by miR-491-5p and miR-214-3p evasion.

Alterations in messenger RNAs (mRNAs) of protein-coding genes can influence the malignant behaviors of acute lymphoblastic leukemia (ALL) cells. According to the prediction from The Cancer Genome Atlas (TCGA) database, we discovered that glutathione peroxidase 1 (GPX1) was up-regulated in acute myeloid leukemia (LAML) tissues, which pushed us to explore the feasible role and its related modulatory mechanism of GPX1 in ALL. In this research, we first proved the high expression of GPX1 in ALL cells compared with normal cells. Functional assays further revealed that the proliferation was obstructed and the apoptosis was facilitated in ALL cells with silenced GPX1. Then, both miR-491-5p and miR-214-3p that were down-regulated in ALL cells were affirmed to target GPX1. Subsequently, VPS9D1 antisense RNA 1 (VPS9D1-AS1) was recognized as the upstream regulator of miR-491-5p-miR-214-3p/GPX1 axis in a competing endogenous RNA (ceRNA) model. Importantly, we proved that VPS9D1-AS1 served as a tumor promoter in ALL through elevating GPX1. In conclusion, VPS9D1-AS1 contributed to ALL cell proliferation through miR-491-5p-miR-214-3p/GPX1 axis, hinting an optional choice for the treatment of ALL.

[Effect of Regulating A20 Expression on NF-κB Expression and Biological Characteristics of Jurkat Cells].

OBJECTIVE: To explore the effect of regulating A20 expression on NF-κB and biological characteristics of Jurkat cells with glucocorticoid (GC) resistance. METHODS: CCRF CEM and Jurkat cells were treated with dexamethasone (DEX) at concentrations of 100、10、1、0.1、0.01 and 0.001 µmol/L, and cultured for 24、48 and 72 h. The proliferation inhibition rate of Jurkat cell was detected by CCK-8. A20 plasmid was constructed, A20-siRNA was designed and synthesized, and transfected into Jurkat cells by liposome. CCK-8 was used to detect the proliferation rates of Jurkat cells in different concentrations of DEX group, DEX combined with A20 plasmid group and A20-siRNA group. The mRNA expression level of NF-κB was detected by RT-qPCR, the protein expression level of NF-κB was detected by Western blot, and the apoptosis of Jurkat cells was examined by flow cytometry. RESULTS: The inhibitory effects of DEX at different concentrations on the growth of CCRF CEM cells were time-dependent (r=0.984, P＜0.05) and concentration-dependent (r=0.966, P＜0.05). At the point of 24 hour, the IC50 approached 1 µmol/L in CCRF CEM cells. Great large differences began to appear between 1 and 10 µmol/L, the proliferation rate of Jurkat cells treated with 1 µmol/L DEX did not show a significant change. Therefore, 1 µmol/L was selected as control group. The cell proliferation rate of A20 plasmid transfection combined with different concentrations of DEX group was lower than that of DEX group and A20-siRNA combined with DEX group. After transfection of A20 plasmid, the expression level of NF-κB was significantly lower than that of control group (P＜0.05), and the apoptotic rate was significantly higher than that of control group (P＜0.05). After transfection of Jurkat cells with A20-siRNA, the expression level of NF-κB was significantly higher than that of control group (P＜0.05). The apoptotic rate of cells in A20-siRNA group was not significantly changed (P＞0.05). CONCLUSION: Jurkat cells are resistant to DEX. A20 overexpression combined with DEX can increase sensitivity of Jurkat cells with GC resistance and decrease the proliferation rate of Jurkat cells, down-regulate the expression level of NF-κB and promote the apoptosis of Jurkat cells.

Leucine-Rich Alpha-2-Glycoprotein1 Gene Interferes with Regulation of Apoptosis in Leukemia KASUMI-1 Cells.

BACKGROUND Leukemia cells have strong proliferation and anti-apoptosis capabilities. The purpose of this study was to investigate the effect of silencing the leucine-rich alpha-2-glycoprotein1 (LRG1) gene, which was found to regulate tumor proliferation and apoptosis in acute myeloid leukemia (AML) cell lines. MATERIAL AND METHODS Plasmid interference technique was used to silence the LRG1 gene in the KASUMI-1 cell line. The cell counting kit-8 (CCK-8) assay was used to test the effect of transduction on cell viability. Cell cycle and apoptosis were detected by flow cytometry. Western blot and quantitative real-time polymerase chain reaction (RT-qPCR) were applied to detect the expression levels of proteins and mRNA, respectively. RESULTS KASUMI-1 cells with the CD34⁺CD38⁻ phenotype were sorted by flow cytometry. After transfection of the siLRG1 plasmid, the level of LRG1 expression was downregulated and cell viability was reduced. Silencing of LRG1 gene blocked KASUMI-1 cells in G0/G1 phase and promoted apoptosis. Further experiments found that LRG1 gene silencing significantly downregulated cell cycle-associated proteins and anti-apoptotic proteins, while upregulating pro-apoptotic proteins. Downregulation of LRG1 gene expression also inhibits signal transduction of the JAK-STAT pathway. CONCLUSIONS LRG1 gene silencing regulates the expression of cyclin and apoptosis-related proteins to reduce cell viability and promote apoptosis, probably through inhibition of the JAK-STAT pathway.

LncRNA ZEB1-AS1 contributes to STAT3 activation by associating with IL-11 in B-lymphoblastic leukemia.

OBJECTIVE: To investigate the role of lncRNA ZEB1-AS1 in B-lineage acute lymphoblastic leukemia (B-ALL). RESULTS: ZEB1-AS1 levels were aberrantly up-regulated in B-ALL. All correlated with STAT3 activation and IL-11 production. Moreover, a high level of ZEB1-AS1 predicted poor prognosis of B-ALL patients. Mechanistically, ZEB1-AS1 could bind to IL-11 and promote IL-11 stability. Down-regulation of ZEB1-AS1 decreased IL-11 production of human bone marrow stromal cells (BMSCs), which led to suppressed proliferation and inhibited IL-11/STAT3 pathway in BALL-1 cells. CONCLUSIONS: ZEB1-AS1 promotes the activation of IL-11/STAT3 signaling pathway by associating with IL-11 in B-ALL.