[Effect of Netrin-1 on VEGFA Expression in T-ALL Cells and Its Related Mechanism].

AbstractObjective: To investigate the effect of the axon guidance factor Netrin-1 on the expression of VEGFA in T cell acute lymphoblastic leukemia(T-ALL) and its related mechanism. METHODS: ELISA assays were applied to detect the levels of Netrin-1 and VEGFA in the bone marrow (BM) samples from children in the T-ALL and control group. The level of Netrin-1 and VEGFA were compared between control children and patients, and the liner correlation between Netrin-1 and VEGFA was analyzed. The T-ALL cells Jurkat and Molt-4 were culture in vitro, and the cells were treated with different concentration of Netrin-1 (0, 25, 50, 100 ng/ml) for 24 h, quantitative RT-PCR (qRT-PCR) and Western blot were used to detect the VEGFA expression in Jurkat, Molt-4 cells. The expression of Netrin-1 receptors in T-ALL cells was detected by qRT-PCR and the interaction between Netrin-1 and receptor in each cells was detected by co-IP. Furthermore, Western blot was used to detect the phosphorylation level of key prateins of AKT signal transduction pathway including Akt and mTOR in T-ALL cells treated with Netrin-1 (100 ng/ml). The expression of VEGFA and phosphorylation of AKT pathway transducers were detected by Western blot, after T-ALL cells treated with Netrin-1 (100 ng/ml) combined with inhibitors specific to Akt or mTOR. RESULTS: The expression level of Netrin-1 and VEGFA in T-ALL patients BM samples were both signi-ficantly higher than that of control group. And the expression level of Netrin-1 was positively correlated with that of VEGFA（r2=0974). With the increase of Netrin-1 concentration, the expression level of VEGFA also increased(P<0.05）. Netrin-1 interacted with its receptor, integrin-ß4 at the Netrin-1 concentration of 100 ng/ml. Further, the treatment of Netrin-1 could increase the phosphorylation of Akt and mTOR, which were the key transducers of AKT pathway. After treatment of T-ALL cells with Netrin-1 (100 ng/mL) and Akt inhibitor, the expression of VEGFA and phosphorylation of Akt or mTOR decreased. When the cells were treated with Netrin-1(100 ng/ml) and mTOR inbititor, the phosphorylation level of mTOR and the expression of VEGFA decreased, the phosphorylation level of Akt increased. CONCLUSION: The expression of Netrin-1 and VEGFA in bone marrow of childred with T-ALL were abnormal, and there was a linear relationship between them. Netrin-1 can interact with its receptor, integrin-ß4 and activate AKT transduction pathway to elevate the expression of VEGFA in T-ALL cells.

Prognostic significance of measurable residual disease based on multiparameter flow cytometry in childhood acute myeloid leukemia. / åŸºäºŽæµå¼ç»†èƒžæœ¯çš„å¯æµ‹é‡æ®‹ç•™ç— å¯¹å„¿ç«¥æ€¥æ€§é«“ç³»ç™½è¡€ç— é¢„åŽæ„ä¹‰çš„å‰çž»æ€§ç ”ç©¶.

OBJECTIVES: To study the prognostic value of measurable residual disease (MRD) for childhood acute myeloid leukemia (AML) by analyzing MRD-guided risk stratification therapy. METHODS: A total of 93 children with AML were prospectively enrolled in this study. Chemotherapy with the 2015-AML-03 regimen was completed according to the risk stratification determined by genetic abnormality at initial diagnosis and MRD and bone marrow cytology after induction therapy I. Multiparameter flow cytometry was used to dynamically monitor MRD and analyze the prognostic effect of MRD on 3-year cumulative incidence of recurrence (CIR) rate, event-free survival (EFS) rate, and overall survival (OS) rate. RESULTS: The 93 children with AML had a 3-year CIR rate of 48%±6%, a median time to recurrence of 11 months (range 2-32 months), a 3-year OS rate of 65%±6%, and a 3-year EFS rate of 50%±5%. After induction therapy I and intensive therapy I, the MRD-positive children had a significantly higher 3-year CIR rate and significantly lower 3-year EFS and OS rates than the MRD-negative children (P<0.05). There were no significant differences in 3-year CIR, EFS, and OS rates between the MRD-positive children with a low risk at initial diagnosis and the MRD-negative children after adjustment of chemotherapy intensity (P>0.05). The multivariate analysis showed that positive MRD after intensive treatment I was a risk factor for 3-year OS rate in children with AML (P<0.05). CONCLUSIONS: MRD has predictive value for the prognosis of children with AML. Based on the MRD-guided risk stratification therapy, reasonable application of chemotherapy may improve the overall prognosis of children with AML.

[Bioinformatics Analysis and Verification of Acute B-Lymphocytic Leukemia in Children with Isolated Bone Marrow Relapse].

OBJECTIVE: To analyze the hub genes affecting the solely bone marrow relapse of childish acute B-cell lymphoblastic leukemia (B-ALL). METHODS: The high-throughput RNA sequencing data were downloaded from TCGA database, the differentially expressed genes were screened by DESeq2 package of R, and the differentially expressed genes were grouped by GO function enrichment analysis and KEGG pathway enrichment analysis. Further, the data of STRING database and Cytoscape software were used to construct protein interaction network, screen hub genes and highly interaction protein sub network, perform GO and KEGG analysis of the hub genes and protein sub network respectively. JASPAR database was used to screen the upstream transcription factor of the hub gene promoter. Survival analysis based on the expression of hub genes was performed with clinical information attached to TCGA database. The bone marrow samples and clinical data of the patients were collected, the analysis results of hub genes were verified through clinical samples. RESULTS: 847 differentially expressed genes were collected, including 813 up-regulated genes, 34 down-regulated genes, 11 hub genes were screened out. The results of survival analysis showed that RPS5、RPS15、RPL23、RPL35、RPS8、RPS27A、RPS3、RPL9、RPS21、RPS7 and RPL38 showed significant effect on the survival of the children, and ZNF460 might be involved in their regulation. The high expressions of RPS3, RPS15, RPS8, RPS27A, and RPS21 had been verified in clinical samples of solely bone marrow relapsed patients. CONCLUSION: RPS3, RPS15, RPS8, RPS27A, RPS21 can be used as biomarkers to indicate the malignant event of solely bone marrow relapse, which may be regulated by ZNF460.

[Clinical features and prognosis of pediatric acute megakaryocytic leukemia].

OBJECTIVE: To study the clinical features and prognosis of children with acute megakaryocytic leukemia (AMKL) and the clinical effect of acute myeloid leukemia 03 (AML03) regimen for the treatment of pediatric AMKL. METHODS: The clinical data were collected from 47 children with AMKL who were diagnosed from May 2011 to December 2019. The treatment outcomes and prognostic factors were analyzed. The Kaplan-Meier method and the log-rank test were used for survival analysis. RESULTS: Among the 47 children with AMKL, 22 with non-Down syndrome-AMKL were treated by the AML03 regimen, with a median follow-up time of 11.4 months. For the 22 non-Down syndrome-AMKL patients, the remission rate of bone marrow cytology was 85% and the negative rate of minimal residual disease (MRD) was 79% after induction Ⅱ, with a 2-year overall survival (OS) rate of (50±13)% and a 2-year event-free survival (EFS) rate of (40±12)%. The group with positive immunophenotypic marker CD56 had significantly lower 2-year EFS and OS rates than the group with negative CD56 (P < 0.05). The group without remission of bone marrow cytology after induction Ⅱ had significantly lower 2-year EFS and OS rates than the group with remission (P < 0.05). The group with positive MRD after induction Ⅱ had a significantly lower 2-year EFS rate than the group with negative MRD (P < 0.05). There was no significant difference in 2-year OS and EFS rates between the patients with transplantation and those without transplantation (P > 0.05). CONCLUSIONS: Children with AMKL tend to have a low remission rate and a poor prognosis. Positive immunophenotypic marker CD56, bone marrow cytology during early treatment response, and MRD results are important factors influencing the prognosis. Allogeneic hematopoietic stem cell transplantation has no significant effect on the prognosis of AMKL.

[Expression of Netrin-1 in Patients with Acute Lymphoblastic Leukemia and Its Clinical Significance].

OBJECTIVE: To investigate the correlation of the Netrin-1 expression level with the clinical characteristics in children with acute lymphoblastic leukemia (ALL) and to explore its possible regulatory mechanism. METHODS: ELISA was used to detect the expression level of Netrin-1 in peripheral blood serum from 48 child ALL patients (newly diagnosed, recurrent), and its relevance with clinical indicators was statistically analyzed. The blood serum samples from 27 children with non malignant hematological diseases were choosen as controls. Leukemia cell lines of Jurkat,Molt-4,SUP-B15 and Raji were cultivated in vitro, after treated with different concentrations of recombinant human Netrin-1 protein， the invasive ability of the cells was detected by Transwell method； the effect of Netrin-1 to the proli feration of cells was detected by CCK-8 method； The expression and phosphorylation level of key molecules, such as FAK,Erk1/2,PI3K and Akt signaling pathway were detected by Western blot. RESULTS: The expression of Netrin-1 in child patients was significantly higher than that of the control group (P<0.05). With the increasing of Netrin-1 level, the level of Plt (r=0.483, P<0.05) increased, while the level of WBC (r=-0.290, P<0.05) decreased, and there were no significant correlation with age, Hb level and the proportion of immature cells in bone marrow. When the concentration of Netrin-1 was 25-50 ng/ml, the level of Netrin-1 positively correlated with WBC (r=0.886, P<0.05) ; the level of Netrin-1 significantly decreased when the patient's WBC was ＞50×109/L and Plt ＞20×109/L(P=0.042，P=0.001); The expression level of Netrin-1 was significantly different in the risk group(P=0.017), and level of Netrin-1 in high-risk group was significantly higher than that in low risk group and middle risk group, but there was no significant difference of Netrin-1 expression in sex, hepatosplenomegaly, MRD, recurrence and chromosome abnormality. Netrin-1 could promote the invasiveness of the four kinds of cells (P<0.05). With the increase of Netrin-1 concentration, the number of cells increased at first and then decreased, and the number of cells in the invading chamber was the highest when the concentration of Netrin-1 was 100 ng/ml; the survival rate of the four kinds of cells significantly increased when the concentration of Netrin-1 was 25 ng/ml(P<0.05), and SUP-B15 cells showed the highest cell survival rate at a concentration of 100 ng/ml; The survival rate of the four kinds of cells showed a tendency : survival of cells increased at low concentration of Netrin-1 and survival of cells decreased at high concentration of Netrin-1. The results of Western blot showed that Netrin-1 activated the phosphorylation level of key molecules such as FAK,Erk1/2,PI3K,Akt signaling pathway (P<0.05). CONCLUSION: There is abnormal expression of Netrin-1 in serum of children with ALL. Netrin-1 may affect the occurrence and development of ALL by increasing the proliferation and invasiveness of leukemia cells, and may become a risk factor of ALL or a potential target in biotherapy.

[E-cadherin Expression in Children with Acute Leukemia and Its Clinical Significance].

OBJECTIVE: To investigate the correlation of E-cadherin expression level with the clinical characterastics in children with acute leukemia (AL), and to explore the possible regulatory mechanism. METHODS: Real-time quantitative RT-PCR was applied to detect the expression level of E-cadherin in bone marrow samples from 135 child patients diagnosed as AL, and its relevance with clinical indicators was statistically analyzed. The expression levels of E-cadherin, ß-catenin, and Akt/p-Akt were detected by using Western blot. The bone marrow samples from 22 children with non-malignant hematological diseases were used as controls. RESULTS: The expression level of E-cadherin significantly decreased in newly diagnosed patients with all 3 types of AL as compared with bone marrow samples from control group (P<0.01). In B-ALL group, compared with standard risk group, E-cadherin expression level significantly decreased in intermediate risk group (P<0.05). Moreover,the expression level of E-cadherin mRNA was also reduced in splenomegaly group (P<0.01). However, the correlation of E-cadherin level with clinical characteristics was not found in T-ALL and AML (P>0.05). The expression level of E-cadherin in the patients from Common-B-ALL group was higher than B-ALL patients with other immunophenotypes (P<0.01), while no significant difference was found among patients grouped by FAB classification. By the correlation analysis of measured data, lower E-cadherin expression level was found to be related with high WBC count and serum lactic dehydrogenase level (LDH) (r=-0.419, r=-0.269), but with low blood platelet count in B-ALL (r=0.335). In T-ALL, expression of E-cadherin was found to be negatively correlated with LDH and percentage of immature cells in the bone marrow (r=-0.567, r=-0.557). In addition, the lower expression of E-cadherin was also found to be related with WBC count and percentage of immature cells in the bone marrow in newly diagnosed AML patients (r=-0.368, r=-0.391). Compared with control group, the expression of E-cadherin was down-regulated significantly (P<0.01), while ß-catenin, Akt significantly was up-regulated in 3 types of AL patients (P<0.01). The expression of p-Akt and p-Akt/Akt was up-regulated significantly in T-ALL (P<0.01). CONCLUSION: Lower expression of E-cadherin is related factor of unfavourable prognosis in children with acute leukemia. The expression deficiency or down-regulation of E-cadherin may activate Wnt/ß-catenin and PI3K/ Akt signaling pathways to promote the genesis and progress of haematological malignancies, thus resulting in a series of malignant biological behaviors in cells. E-cadherin may be a new prognostic indicator for pediatric acute leukemia, thus to guide individualized hemotherapy.

[Effect of 4' -Hydroxywogonin on Proliferation and Apoptosis of Human Acute Lymphoblastic Leukemia Cells].

OBJECTIVE: To investigate the effect of 4' -hydroxywogonin on proliferation and apoptosis of human acute lymphoblastic leukemia SUP-B15 and Jurkat cells, and to analyze its possible mechanism. METHODS: SUP-B15 and Jurkat cells were cultivated in vitro and treated with different concentrations of 4' -hydroxywogonin, the inhibitory effect of 4' -hydroxywogonin on the proliferation of SUP-B15 and Jurkat cells was detected by CCK-8 method; the cell apoptosis was examined by the flow cytometry with Annexin V-APC/7-AAD donble staining; the expression of C-MYC, BCL-2 and cleaved caspase 3 in SUP-B15 and Jurkat cells were measured with Western blot. RESULTS: 4' -hydroxywogonin inhibited the proliferation of SUP-B15 and Jurkat cells in a dose-dependent manner (r=0.78, r=0.89), with IC50 value of (6.32± 0.53) µg/ml in SUP-B15 cells and (12.04± 0.42) µg/ml in Jurkat cells at 24 h. The early apoptotic rate of cell was also enhanced with the increase of 4' -hydroxywogonin concentrations. The results of Western blot showed that 4' -hydroxywogonin could down-regulate the expression of proliferation-related molecule C-MYC(P<0.01) and apoptosis-related molecule BCL-2(P<0.01), the expression of apoptosis-related molecule cleaved caspase 3 was up-regulate(P<0.01). CONCLUSION: 4' -hydroxywogonin shows the effects of anti-tumor by inducing cell apoptosis and inhibiting cell proliferation, its molecular mechanism maybe relate with down-regulation of C-MYC and BCL-2 expression and up-regulation of the cleaved caspase 3 expression.

[Expression of ß-integrin family members in children with T-cell acute lymphoblastic leukemia].

OBJECTIVE: To study the expression of ß-integrin family members in children with T-cell acute lymphoblastic leukemia (T-ALL) and their significance. METHODS: Quantitative real-time PCR analyses were performed to assess the expression levels of ß-integrin family members in bone marrow samples from 22 children with newly-diagnosed T-ALL and 21 controls (16 children with non-malignant hematologic disease and 5 healthy donors with bone marrow transplantation). Jurkat cells were treated with integrin inhibitor arginine-glycine-aspartate (Arg-Gly-Asp, RGD) peptide. The cell viability and apoptosis rate were determined by CCK8 assay and flow cytometry respectively. RESULTS: The mRNA levels of integrins ß2, ß3, and ß5 were significantly lower in children with T-ALL than in controls (P<0.05). In T-ALL patients, high integrin ß3 expression was associated with lower white blood cell counts (<100×109/L), minimal residual disease (MRD) positivity, and day 33 bone marrow negative remission (P<0.05). In T-ALL patients, higher integrin ß5 expression was associated with relapse of T-ALL (P<0.05). Based on survival curve analysis, higher integrin ß3 expression was related to lower event-free survival and overall survival rates. RGD peptide treatment inhibited the proliferation of Jurkat cells and increased their apoptosis rate (P<0.05). CONCLUSIONS: ß-Integrin may play a role in the occurrence and development of T-ALL by affecting cell proliferation and apoptosis. The expression of integrin ß5 is closely related to the risk of relapse of T-ALL. The expression of integrin ß3 is closely related the treatment response and prognosis of T-ALL.

[PRPS1 Expression in Children with Acute Leukemia and Its Clinical Significance].

OBJECTIVE: To investigate the correlation between the expression level of PRPS1 and the clinical characteristics in children with acute leukemia(AL). METHODS: Real-time quantitative RT-PCR and Western blot were used to detect the level of PRPS1 mRNA and protein expression in bone marrow samples from 176 patients diagnosed as AL (126 cases were newly diagnosed and 50 cases in complete remission), and its relevance with clinical indicators was statistically analyzed. The bone marrow samples from 21 children with non-malignant hematological disease were used as controls. RESULTS: (1)In B-ALL group, the level of PRPS1 mRNA in newly diagnosed patients were significantly higher than that in control and than that in complete remission patients (both P<0.0001). In T-ALL and AML group, differences was only observed between newly diagnosed patients and complete remission patients(both P<0.0001); (2)In B-ALL group, the expression level of PRPS1 increase with along risk enhancement (P<0.01), while no significant difference was observed in T-ALL (P>0.05). In AML patients, expression difference was shown between low risk group and high risk group(P<0.05); (3)High PRPS1 mRNA expression level were associated with high WBC counts and MRD positive in B-ALL patients (P=0.020, P=0.026, respectively); (4)Expression of NT5C2, an essential gene for relapse and drug resistance, was found to be positively correlated with PRPS1 expression in AL samples(P<0.05). CONCLUSION: High expression of PRPS1 is relevant factor of unfavourable prognosis in B-ALL children, which suggest PRPS1 may be a new indicator for prognosis of pediatric B-ALL and an index to guide individualized chemotherapy.

SIRT4 accelerates Ang II-induced pathological cardiac hypertrophy by inhibiting manganese superoxide dismutase activity.

AIMS: Oxidative stress contributes to the development of cardiac hypertrophy and heart failure. One of the mitochondrial sirtuins, Sirt4, is highly expressed in the heart, but its function remains unknown. The aim of the present study was to investigate the role of Sirt4 in the pathogenesis of pathological cardiac hypertrophy and the molecular mechanism by which Sirt4 regulates mitochondrial oxidative stress. METHODS AND RESULTS: Male C57BL/6 Sirt4 knockout mice, transgenic (Tg) mice exhibiting cardiac-specific overexpression of Sirt4 (Sirt4-Tg) and their respective controls were treated with angiotensin II (Ang II, 1.1 mg/kg/day). At 4 weeks, hypertrophic growth of cardiomyocytes, fibrosis and cardiac function were analysed. Sirt4 deficiency conferred resistance to Ang II infusion by significantly suppressing hypertrophic growth, and the deposition of fibrosis. In Sirt4-Tg mice, aggravated hypertrophy and reduced cardiac function were observed compared with non-Tg mice following Ang II treatment. Mechanistically, Sirt4 inhibited the binding of manganese superoxide dismutase (MnSOD) to Sirt3, another member of the mitochondrial sirtuins, and increased MnSOD acetylation levels to reduce its activity, resulting in elevated reactive oxygen species (ROS) accumulation upon Ang II stimulation. Furthermore, inhibition of ROS with manganese 5, 10, 15, 20-tetrakis-(4-benzoic acid) porphyrin, a mimetic of SOD, blocked the Sirt4-mediated aggravation of the hypertrophic response in Ang II-treated Sirt4-Tg mice. CONCLUSIONS: Sirt4 promotes hypertrophic growth, the generation of fibrosis and cardiac dysfunction by increasing ROS levels upon pathological stimulation. These findings reveal a role of Sirt4 in pathological cardiac hypertrophy, providing a new potential therapeutic strategy for this disease.

Netrin-1 suppresses the MEK/ERK pathway and ITGB4 in pancreatic cancer.

The axon guidance factor netrin-1 promotes tumorigenesis in multiple types of cancers, particularly at their advanced stages. Here, we investigate whether netrin-1 is involved in the in vivo growth of pancreatic adenocarcinoma. We show that netrin-1 is significantly under-expressed in stage-I/II pancreatic ductal adenocarcinoma (PDAC). Netrin-1 over-expression effectively arrests the growth of xenografted PDAC cells without decreasing cell proliferation or increasing apoptosis in two-dimensional cultures in vitro. Integrin-beta4 (ITGB4) expression is significantly reduced, and ITGB4-knockdown mimics the tumor-suppressive effect of netrin-1, implying that ITGB4 is a main target of netrin-1 in constraining PDAC. We further show that netrin-1 signals to UNC5B/FAK to stimulate nitric oxide production, which promotes PP2A-mediated inhibition of the MEK/ERK pathway and decreases phosphorylated-c-Jun recruitment to the ITGB4 promoter. Our findings suggest that netrin-1 can suppress the growth of PDAC and provide a mechanistic insight into this suppression.

Overexpression of mitofilin in the mouse heart promotes cardiac hypertrophy in response to hypertrophic stimuli.

AIMS: Mitofilin was originally described as a heart muscle protein because of its abundance in the heart tissue; however, its function in the heart is still to be elucidated. Thus, this study aims at investigating the role of mitofilin in the heart in response to hypertrophic stimuli. RESULTS: In this study, a significant increase in mitofilin expression was observed in the hearts of patients with hypertrophic cardiomyopathy. Transgenic (TG) mice with cardiomyocyte-specific overexpression of mitofilin were generated, and cardiac hypertrophy was introduced by transverse aortic constriction (TAC) or chronic infusion of isoproterenol (ISO). In TG mice overexpressing mitofilin, the level of cardiac hypertrophy was significantly greater than that in wild-type (WT) mice after TAC and ISO stimulation. A detailed analysis showed that compared with WT mice, the level of reactive oxygen species was increased after TAC and ISO induction and mitochondrial oxidative phosphorylation (OXPHOS) activity in the TG hearts was lower. These alterations may contribute to the aggravated cardiac hypertrophy observed in response to TAC and ISO stimulation. CONCLUSION: Over-expression of mitofilin promotes cardiac hypertrophy under pathological conditions both in vivo and in vitro. INNOVATION: Mitofilin, a mitochondria protein, is shown to be related to cardiac hypertrophy for the first time, which enhances our understanding of the role of mitochondria in cardiac hypertrophy.