MicroRNA 34b inhibits cell proliferation in pediatric acute myeloid leukemia via regulating LDHA.

OBJECTIVE: To elucidate the regulatory effect of microRNA-34b on the occurrence of pediatric acute myeloid leukemia and the underlying mechanism. PATIENTS AND METHODS: The expression of microRNA-34b in the bone marrow of 72 children with newly diagnosed acute myeloid leukemia (AML) was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The relationship between microRNA-34b expression and pathological characteristics was analyzed. Kaplan-Meier curve was introduced for evaluating the prognostic value of microRNA-34b in pediatric AML. The regulatory effects of microRNA-34b on proliferation, cell cycle, and apoptosis of leukemia cells were accessed by cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. Bioinformatics prediction and dual-luciferase reporter gene assay were conducted to evaluate the binding between microRNA-34b and lactate dehydrogenase A (LDHA). LDHA expression after overexpression of microRNA-34b was determined by qRT-PCR and Western blot. Rescue experiments were conducted to verify whether microRNA-34b could regulate proliferative and apoptotic behaviors of leukemia cells by suppressing LDHA expression. RESULTS: MicroRNA-34b was markedly downregulated in AML children. Low expression of microRNA-34b was correlated to FAB typing, cytogenetic abnormality, and day 7 response to the treatment of pediatric AML. By collecting the follow-up data, it was found that low expression of microRNA-34b was correlated to the poor prognosis of AML. Overexpression of microRNA-34b inhibited proliferative ability and cell cycle progression, but accelerated apoptosis of AML cells. Dual-luciferase reporter gene assay verified that microRNA-34b could bind to LDHA, thereafter inhibiting LDHA expression. Overexpression of LDHA reversed the regulatory effects of microRNA-34b on proliferation, cell cycle, and apoptosis of AML cells. CONCLUSIONS: We found that microRNA-34b is lowly expressed in pediatric AML patients, and low expression of microRNA-34b may serve as an indicator of malignant progression and poor prognosis of pediatric AML. MicroRNA-34b may affect the proliferation and apoptosis of leukemia cells by regulating the expression of LDHA.

MiR-410 regulates malignant biological behavior of pediatric acute lymphoblastic leukemia through targeting FKBP5 and Akt signaling pathway.

OBJECTIVE: The aim of this study was to investigate the role of miR-410 in regulating the proliferation and apoptosis of pediatric acute lymphoblastic leukemia (ALL) cells and to explore the possible underlying mechanism. PATIENTS AND METHODS: The expression level of miR-410 in ALL cases and cells was detected by real-time fluorescence quantitative polymerase chain reaction (qRT-PCR). Luciferase reporter gene assay was performed to evaluate the interaction between miR-410 and FKBP5. MTT and colony formation assay were used to determine the effect of miR-410 on the proliferation and colony formation ability of ALL cells. The effect of miR-410 on cell apoptosis was measured by Annexin V-fluorescein isothiocyanate 1 (FITC) and propidium iodide (PI). Western blot was used to analyze the effect of miR-410 on the protein expression levels of phosphorylated Akt (p-Akt) and cleaved caspase-3. RESULTS: In our investigation, miR-410 was significantly up-regulated in ALL cases and cells. We searched three public databases to predict the potential target of miR-410, and found that FKBP5 was a direct target of miR-410. Meanwhile, Luciferase reporter gene assay confirmed our hypothesis. The overexpression of miR-410 accelerated the proliferation and colony formation ability of ALL cells, whereas remarkably decreased cell apoptosis rate. Western blotting showed that miR-410 inhibited the activation of Akt signaling pathway. However, FKBP5 could reverse the effects of miR-410. CONCLUSIONS: MiR-410 regulated the proliferation, colony formation and apoptosis of ALL cells through targeting FKBP5 and Akt signal pathway, indicating that miR-410 might be a potential therapeutic target for the treatment of ALL.

Long noncoding RNA LINC00265 predicts the prognosis of acute myeloid leukemia patients and functions as a promoter by activating PI3K-AKT pathway.

OBJECTIVE: Mounting evidence suggests that long noncoding RNAs (lncRNAs) function in multiple cancers. This study aimed to determine the expression, clinical significance, and possible biological function of a novel lncRNA LINC00265 in acute myeloid leukemia (AML). PATIENTS AND METHODS: The expression levels of LINC00265 were systematically evaluated in TCGA datasets. RT-PCR was performed to examine the expression level of LINC00265 in bone marrow and serum obtained from AML patients and healthy controls. The clinical data were interpreted by x2 test, Kaplan-Meier analyses, univariate analysis, and multivariate analysis. The functional role of LINC00265 was verified using cell experiments. Western blotting was used to examine the modulatory effect of LINC00265 on AKT/PI3K pathway in AML. RESULTS: LINC00265 was significantly highly expressed in the bone marrow and serum of AML patients. High serum LINC00265 was significantly associated with FAB classification and cytogenetics. ROC analyses showed that serum LINC00265 levels were reliable in distinguishing patients with AML from normal controls. Clinical assay indicated that AML patients with higher serum LINC00265 expression suffered poorer overall survival. Functionally, overexpression of LINC00265 suppressed the capability of proliferation, migration and invasion in AML cell lines. By using Western blot, we further illustrated that LINC00265 activated PI3K/AKT signaling in AML cell lines. CONCLUSIONS: Our findings not only demonstrated that LINC00265 contributes to AML proliferation, migration and invasion via modulation of PI3K/AKT signaling, but also suggested the potential value of LINC00265 as a clinical prognostic and a diagnostic marker for AML.