Cyclophosphamide-induced GPX4 degradation triggers parthanatos by activating AIFM1.

Cyclophosphamide is an alkylating agent used to treat a variety of cancers, including leukemia. Here, we show a previously unrecognized role of cyclophosphamide in triggering the protein degradation of glutathione peroxidase 4 (GPX4), a phospholipid hydroperoxidase that protects cells from oxidative damage. Mechanistically, we found that the ubiquitin-proteasome system, but not autophagy, mediates cyclophosphamide-induced degradation of GPX4 in human leukemia cell lines. Surprisingly, cyclophosphamide-induced degradation of GPX4 leads to caspase-independent parthanatos, but not lipid peroxidation-mediated ferroptosis, through the nuclear translocation of apoptosis-inducing factor mitochondria-associated 1 (AIFM1). Consequently, the overexpression of GPX4 or the knockdown of AIFM1 limits the anticancer activity of cyclophosphamide in vitro and in xenograft tumor models. These findings establish a new framework for understanding the central role of GPX4 in blocking oxidative cell death.

microRNA-155-5p initiates childhood acute lymphoblastic leukemia by regulating the IRF4/CDK6/CBL axis.

Acute lymphoblastic leukemia (ALL) is a common malignancy in children. In this study, we aimed to explore putative mechanisms of microRNA-155-5p (miR-155-5p) involvement in childhood ALL (cALL) via interactions with casitas B-lineage lymphoma (CBL), interferon regulatory factor 4 (IRF4), and cyclin-dependent kinase 6 (CDK6). Bioinformatic analysis was performed initially to identify differentially expressed genes in cALL. The expression levels of miR-155-5p, CBL, IRF4, and CDK6 in peripheral blood lymphocytes from clinical ALL samples were determined using RT-qPCR and Western blot assays. A dual-luciferase reporter gene assay was used to ascertain a possible targeting relationship between miR-155-5p and CBL, CCK-8 assay and flow cytometry were used to measure cell activity and apoptosis of ALL cells. Co-IP was performed to investigate the interaction between CBL and IRF4 and the ubiquitination level of IRF4. Furthermore, in vivo validation was performed inducing xenograft tumor models with ALL cells in nude mice. As indicated by bioinformatic analysis, miR-155-5p and CDK6 were upregulated and CBL was downregulated in ALL. miR-155-5p was found to target CBL to inhibit CBL expression. miR-155-5p promoted the proliferation of ALL cells and inhibited their apoptosis by inhibiting the expression of CBL, which otherwise degraded IRF4 protein through ubiquitination, leading to inhibited CDK6 expression. Collectively, the results show that miR-155-5p can promote the development of cALL via the regulation on CBL-mediated IRF4/CDK6 axis.

Polyethylene glycol diacrylate scaffold filled with cell-laden methacrylamide gelatin/alginate hydrogels used for cartilage repair.

Natural cartilage tissue has excellent mechanical properties and has certain cellular components. At this stage, it is a great challenge to produce cartilage scaffolds with excellent mechanical properties, biocompatibility, and biodegradability. Hydrogels are commonly used in tissue engineering because of their excellent biocompatibility; however, the mechanical properties of commonly used hydrogels are difficult to meet the requirements of making cartilage scaffolds. The mechanical properties of high concentration polyethylene glycol diacrylate (PEGDA) hydrogel are similar to those of natural cartilage, but its biocompatibility is poor. Low concentration hydrogel has better biocompatibility, but its mechanical properties are poor. In this study, two different hydrogels were combined to produce cartilage scaffolds with good mechanical properties and strong biocompatibility. First, the PEGDA grid scaffold was printed with light curing 3D printing technology, and then the low concentration GelMA/Alginate hydrogel with chondral cells was filled into the PEGDA grid scaffold. After a series of cell experiments, the filling hydrogel with the best biocompatibility was screened out, and finally the filled hydrogel with cells and excellent biocompatibility was obtained. Cartilage tissue engineering scaffolds with certain mechanical properties were found to have a tendency of cartilage formation in in vitro culture. Compared with the scaffold obtained by using a single hydrogel, this molding method can produce a tissue engineering scaffold with excellent mechanical properties on the premise of ensuring biocompatibility, which has a certain potential application value in the field of cartilage tissue engineering.

Drug release evaluation of Paclitaxel/Poly-L-Lactic acid nanoparticles based on a microfluidic chip.

Paclitaxel is a commonly used drug in the medical field because of its strong anticancer effect. However, it may produce relatively severe side effects (i.e., allergic reactions). A major characteristic of paclitaxel is low solubility in water. Special solvents are used for dissolving paclitaxel and preparing the paclitaxel drugs, while the solvents themselves will cause certain effects. Polyoxyethylene castor oil, for example, can cause severe allergic reactions in some people, and the clinical use is limited. In this study, we developed a new Paclitaxel/Poly-L-Lactic Acid (PLLA) nanoparticle drug, which is greatly soluble in water, and carried out in vitro drug sustained release research on it and the original paclitaxel drug. However, because the traditional polymer drug carrier usually uses dialysis bag and thermostatic oscillation system to measure the drug release degree in vitro, the results obtained are greatly different from the actual drug release results in human body. Therefore, this paper adopts the microfluidic chip we previously developed to mimic the human blood vessels microenvironment to study the sustained-release of Paclitaxel/PLLA nanoparticles to make the results closer to the release value in human body. The experimental results showed that compared with the original paclitaxel drug, Paclitaxel/PLLA nanoparticles have a long-sustained release time and a slow drug release, realizing the sustained low-dose release of paclitaxel, a cell cycle-specific anticancer drug, and provided certain reference significance and theoretical basis for the research and development of anticancer drugs.

[Analgesic Efficacy of Compound Lidocaine Cream in the Lumbar Puncture of Children with Hematologic Tumor].

OBJECTIVE: To assess the analgesic efficacy of compound lidocaine cream in lumbar puncture of children with leukemia and lymphoma. METHODS: 312 leukemia and lymphoma children necessarily undergone lumbar puncture were divided into compound lidocaine cream (cream) group and compound lidocaine injection (injation) group as control with 156 cases respectively according to the will of inpatient children and their family. For cream group, compound lidocaine cream was smeared on the skin around the lumbar puncture point evenly and covered with sterile and transparent dressing for about one hour before lumbar puncture. Then the cream and transparent dressing were removed and lumbar puncture was performed after regular disinfection. For control group, 2% compound lidocaine was injected as local anesthesia before lumbar puncture. The extent of pain was evaluated by Wong-Baker Faces Pain Rating Scale and FLACC Scale as well as children's physiological indexes (heart rate, breathing, blood pressure). The lumbar puncture success rate and the discomfortableness as well as family satisfaction were recorded by special person. RESULTS: Compared with control group, the incidence of pain and discomfortableness in cream group significantly reduced, and the family satisfaction significantly increased (P＜0.05). There were obviously differences in the physiological indexes (heart rate, breathing, systolic blood pressure) before and after lumbar puncture in control group (P＜0.05). However, the physiological indexes in cream group had no obvious change. There was no difference on the success rate of lumbar puncture between the two methods of anesthesia. CONCLUSION: Compound lidocaine cream has significantly analgesic effect which can relieving pain caused by lumbar puncture for children.

[Influence of HMGB1/MAPK/m-TOR signaling pathway on cell autophagy and chemotherapy resistance in K562 cells].

OBJECTIVE: To observe the effect of high-mobility group box 1 (HMGB1) on autophagy and chemotherapy resistance in human leukemiacell line (K562) cells, and to explore the underlying mechanisms.
 Methods: The K562 cells were cultured in vitro and divided into 6 groups: a chemotherapeutic group, a chemotherapeutic control group, a HMGB1 preconditioning group, a HMGB1 preconditioning control group, a HMGB1 siRNA group and a siRNA control group. The chemotherapeutic group was further divided into a vincristine (VCR) group, an etoposide (VP-16) group, a cytosine arabinoside (Ara-C) group, a adriamycin (ADM) group and a arsenic trioxide (As2O3) group. The cell activity was evaluated by cell counting kit-8. The protein levels of HMGB1, microtubule-associate protein1light chain3 (LC3), AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (m-TOR) were determined by Western blotting. The level of serum HMGB1 was evaluated by enzyme-linked immunosorbent assay (ELISA). The autophagy was examined by monodansylcadaverine staining and observed under transmission electron microscopy.
 Results: Compared with the control group, the cell activity was significantly decreased and the level of serum HMGB1 was significantly increased in the chemotherapeutic (VCR, VP-16, Ara-C, ADM and As2O3) groups (all P<0.05). Compared with the control group, the cell activity and the level of serum HMGB1 were significantly increased in the HMGB1 preconditioning group (both P<0.05). Compared with the siRNA control group, the cell activity and the level of serum HMGB1 were significantly decreased in the HMGB1 siRNA group (both P<0.05). Compared with the control group, the expression of LC3-II and the formation of autophagic bodies were increased in the HMGB1 preconditioning group (both P<0.05), the p-AMPK expression was increased and p-mTOR expression was decreased (both P<0.05).
 Conclusion: HMGB1 can increase the autophagy and promote chemotherapy resistance through the pathway of AMPK/m-TOR in K562 cells.

Behavioural and emotional outcomes in school-aged children after surgery or transcatheter closure treatment for ventricular septal defect.

OBJECTION: We aimed to assess and compare the behavioural and emotional outcomes of school-aged children after surgery or transcatheter closure for ventricular septal defect and investigate the risk factors for developing abnormal behavioural problems with the condition. METHODS: In this study, we included 29 children, including 20 boys, with ventricular septal defect who underwent surgery and 35 children, including 21 boys, who underwent transcatheter closure (6-13 years old) and their age- and sex-matched best friends (n = 56) and their parents. The Child Behavior Checklist was used to obtain standardised parents' reports of behavioural and emotional problems in children. The 28-item version of the General Health Questionnaire was used to assess parents' psychological distress. Pearson correlation and logistic regression were used to analyse risk factors for developing behaviour problems. RESULTS: Behavioural problems were greater for boys and girls undergoing surgery or transcatheter closure than controls. The behavioural problems were mainly depression, somatic complaints, and social withdrawal for boys and thought problems, depression, somatic complaints, and social withdrawal for girls. Depression and somatic complaints were greater for boys undergoing surgery than for boys undergoing transcatheter closure. Behavioural problems did not differ between treatment groups for girls. Risk factors for developing behavioural problems were age at the time of ventricular septal defect repair (p = 0.03; odds ratio = 2.35), skin scar (p = 0.04; odds ratio = 3.12), post-operative atrioventricular block (p = 0.03; odds ratio = 2.81), and maternal anxiety (p < 0.01; odds ratio = 4.5). CONCLUSION: School-aged children who underwent repair of ventricular septal defect regardless of the type of treatment (surgery or transcatheter closure) exhibit internalising behavioural problems. Risk factors for developing problems are young age, scarring, post-operative atrioventricular block, and maternal anxiety. In particular, maternal anxiety is the most important risk factor.

Cognitive P300-evoked potentials in school-age children after surgical or transcatheter intervention for ventricular septal defect.

BACKGROUND: Some studies have suggested that neurological development may be adversely affected in children with severe coronary heart disease who have undergone long periods of deep hypothermic cardiopulmonary bypass (CPB). Reports of cognitive function in VSD patients in whom surgical repair required only a relatively brief period of CPB are rare. Also, CPB is unnecessary for VSD patients undergoing transcatheter closure. The aim of this study was to assess the cognitive function in patients with ventricular septal defect. METHODS: A total of 29 patients treated with surgery, and 35 treated with transcatheter closure and their age- and sex-matched best friends completed the cognitive P300 auditory-evoked potentials test and the intelligence test. RESULTS: The patients and their best friends had normal intelligence quotient; however, the patients had longer P300 peak latencies in cranial frontal lobe and cranial vertex leads (329.2 ± 24.8 and 335.1 ± 20.0 ms) than the healthy controls did (319.1 ± 20.6 and 313 ± 18.2 ms) (P < 0.05). Patients who underwent surgery had longer P300 peak latency in the cranial frontal lobe and cranial vertex leads than did those with transcatheter closure and controls. When cardiopulmonary bypass and aortic clamping were used, the duration was associated with P300 peak latency for patients (P < 0.05). CONCLUSION: VSD patients, especially those undergoing surgery, showed poor cognitive function, which may be associated with duration of cardiopulmonary bypass or aortic-clamping.