Tetraarsenic tetrasulfide triggers ROS-induced apoptosis and ferroptosis in B-cell acute lymphoblastic leukaemia by targeting HK2.

PURPOSE: Acute lymphoblastic leukemia (ALL) is the most common type of cancer diagnosed in children. Despite cure rates of higher than 85 %, refractory or relapsed ALL still exhibits a bleak prognosis indicative of the dearth of treatment modalities specific for relapsed or refractory ALL. Prior research has implicated metabolic alterations in leukemia pathogenesis, and literature on the therapeutic efficacy of arsenic compounds targeting metabolic pathways in B-cell acute lymphoblastic leukemia (B-ALL) cells is scarce. METHODS: A compound extracted from realgar, tetraarsenic tetrasulfide (As4S4), and its antitumor effects on B-ALL were experimentally examined in vitro and in vivo. RESULTS: As4S4 apparently targets B-ALL cells by inducing specific cellular responses, including apoptosis, G2/M arrest, and ferroptosis. Interestingly, these effects are attributed to reactive oxygen species (ROS) accumulation, and increased ROS levels have been linked to both the mitochondria-dependent caspase cascade and the activation of p53 signaling. The ROS scavenger N-acetylcysteine (NAC) can counteract the effects of As4S4 treatment on Nalm-6 and RS4;11 cells. Specifically, by targeting Hexokinase-2 (HK2), As4S4 induces alterations in mitochondrial membrane potential and disrupts glucose metabolism, leading to ROS accumulation, and was shown to inhibit B-ALL cell proliferation in vitro and in vivo. Intriguingly, overexpression of HK2 can partially desensitize B-ALL cells to As4S4 treatment. CONCLUSION: Tetraarsenic tetrasulfide can regulate the Warburg effect by controlling HK2 expression, a finding that provides both new mechanistic insight into metabolic alterations and pharmacological evidence for the clinical treatment of B-ALL.

HDAC5 promotes Mycoplasma pneumoniae-induced inflammation in macrophages through NF-κB activation.

Excessive inflammation is fundamental in the pathophysiology of Mycoplasma pneumoniae (MP)-induced respiratory infection in children. Histone deacetylase 5 (HDAC5) is involved in the regulation of inflammation, however, whether it associates with immunity against MP infection is not determined. We report here that HDAC5 expression is decreased in peripheral blood mononuclear cells (PBMCs) from Mycoplasma pneumoniae pneumonia (MPP) children as well as in MP-infected peritoneal and THP-1 macrophages. Functionally, HDAC5 overexpression promotes and its depletion inhibits MP-induced proinflammatory cytokine production in THP-1 macrophages. Mechanistically, HDAC5 modulates NF-κB activation in MP-infected THP-1 macrophages, and moreover, inhibition of NF-κB activity via pharmacological inhibitor Bay 11-7082 attenuates the promotive effect of HDAC5 on MP-induced proinflammatory cytokine production in THP-1 macrophages, hence suggesting that HDAC5 promotes MP-induced inflammatory response in macrophages through NF-κB activation. Together, this study reveals a novel function of HDAC5 in promoting MP-induced inflammation and implies the possible clinical significance in controlling inflammation that underlies MMP pathophysiology.

YKL-40 levels are associated with disease severity and prognosis of viral pneumonia, but not available in bacterial pneumonia in children.

BACKGROUND: Viral pneumonia is the main type of community-acquired pneumonia (CAP) in children. YKL-40, a chitinase-like protein, is regarded as a biomarker of the degree of inflammation. METHODS: Children who were diagnosed with CAP, including viral pneumonia, bacterial pneumonia, and dual infection, were included in the cohort study. The pathogenic diagnosis depended on PCR and immunoassay test. YKL-40 levels were examined twice by enzyme-linked immunoassay (ELISA). RESULTS: Serum YKL-40 levels were higher in patients with pneumonia than in healthy controls. The admission levels of YKL-40 in serum and Bronchoalveolar lavage (BALFs) indicated a positive correlation with the serum levels of C-reactive protein and other inflammatory cytokines (IL-6 and TNF-α). The disease severity have no correlation with the admission serum levels of YKL-40. Meanwhile, reductions in YKL-40 levels from initial admission levels to day 5 post-admission were correlated with disease severity. The multiple logistic analysis indicated the decreased extent of serum YKL-40 level as an independent prognostic predictor of severe cases in patients with viral pneumonia. CONCLUSIONS: Reductions in serum YKL-40 levels on day 5 after receiving therapy is a possible prognostic biomarker for children with viral pneumonia.

Panel reactive antibody in thalassemic serum inhibits proliferation and differentiation of cord blood CD34+ cells in vitro.

Thalassemic children are at a high risk of graft rejection in cord blood transplantation. To investigate this possible mechanism, the authors evaluated the effect of panel reactive antibody on the growth of CD34(+) cells in vitro. On semisolid medium, CD34(+) cells derived from cord blood were incubated with thalassemic serum, and colony-forming units were counted after 10 days of culture. After incubation with serum-specific panel reactive antibody, profound decreases were found in the numbers of CFU-GM, CFU-GEMM and BFU-E compared with controls. The results indicated that serum-specific panel reactive antibody might have an apparent inhibition effect on proliferation and differentiation of cord blood CD34(+) cells.

[Effect of the serum panel reactive antibody on proliferation and differentiation of cord blood CD34+ cells in vitro].

OBJECTIVE: The low rate of engraftment in children with beta-thalassemia has seriously restricted the popularity of the hematopoietic stem cell transplantation (HSCT). Panel reactive antibody (PRA) has been regarded as one of the important factors for the success of kidney transplantation. Poly-transfusion before transplantation is associated with the production of PRA. Also PRA is produced in the children with beta-thalassemia major who need poly-transfusion for life. PRA might be one of factors inducing the low rate of engraftment in children with beta-thalassemia. This study focused on observing the effect of PRA on the proliferation, differentiation, apoptosis and necrosis of cord blood CD34(+) cells in vitro by incubating the cord blood CD34(+) cells with serum containing PRA. METHOD: Seven samples of cord blood were collected and the HLA typing for every sample was done. Seven sera positive for PRA and seven negative sera were selected respectively. Mononuclear cells (MNCs) were obtained by Ficoll-Hypaque density gradient centrifugation. CD34(+) cells were isolated from MNCs by positive selection using an immunomagnetic separation (CD34(+) progenitor cell isolation kit and auto-MACS). The CD34(+) cells of umbilical cord blood were incubated with the serum and complement in the following groups: A (absence of serum), B (presence of PRA positive serum), C (presence of PRA positive serum and complement), D (presence of complement), and E (presence of PRA negative serum). After incubation the samples were centrifuged and the supernatant was collected for LDH detection. At the same time the CD34(+) cells were harvested for assessing the expression of Annexin V and CD95 of the CD34(+) cells by flow cytometry and also for the detection of the DNA synthesis by (3)H-TaR incorporation. Meanwhile the cells were inoculated into the methylcellulose cultural system. The proliferation and hematopoietic potential of the CD34(+) cell of cord blood by the colony formation assay were detected on the day 10. RESULT: The concentration of LDH in group A was (20.71 +/- 2.81) U/L, which was significantly lower than that in group B (64.28 +/- 5.12) U/L and group C (84.29 +/- 4.99) U/L. The concentration of LDH in group B was significantly lower than that in group C, while there were no significant differences in the concentration of LDH among groups A, D and E (P > 0.05). The cpm in group A was (22 629 +/- 3288), which was significantly higher than that in group B (4598 +/- 2178) and group C (1626 +/- 1192). And the cpm in group B was significantly higher than that in group C. There were no significant differences in the cpm among groups A, D and E (P > 0.05). On day 10 of culture, the total colonies, granulocyte-macrophage colony forming unit (CFU-GM), mixed colony forming unit (CFU-GEMM) and erythroid burst colony forming unit (BFU-E) in group A were significantly higher than that in group B and C. The total colonies, CFU-GM and CFU-GEMM in group B were significantly higher than those in group C. No significant differences were found in the total colonies, CFU-GM, CFU-GEMM and BFU-E among groups A, D and E (P > 0.05). There were no statistically significant differences in the CD95 and Annexin V expression among all the groups (P > 0.05). CONCLUSION: PRA could impair the membrane, decrease the DNA synthesis, and inhibit the colony formation of CD34(+) cord blood cells, which could be strengthened by the presence of the complement at the given concentration in our study. PRA had no significant influence on the apoptosis of CD34(+) cells in vitro.