PKM2 Interacts With the Cdk1-CyclinB Complex to Facilitate Cell Cycle Progression in Gliomas.

PKM2 is a phosphotyrosine-binding glycolytic enzyme upregulated in many cancers, including glioma, and contributes to tumor growth by regulating cell cycle progression. We noted, however, that in multiple glioma cell lines, PKM2 knock-down resulted in an accumulation of cells in G2-M phase. Moreover, PKM2 knock-down decreased Cdk1 activity while introducing a constitutively active Cdk1 reversed the effects of PKM2 knock-down on cell cycle progression. The means by which PKM2 increases Cdk1 activity have not been described. Transient interaction of T14/Y15-phosphorylated Cdk1 with cyclin B allows Cdk7-mediated pT161 Cdk1 phosphorylation followed by cdc25C-mediated removal of pT14/Y15 and activation of Cdk1 in cycling cells. In the present course of investigation, PKM2 modulation did not influence Cdk7 activity, but phosphotyrosine binding forms of PKM2 co-immunoprecipitated with pY15-containing Cdk1-cyclinB and enhanced formation of active pT161 Cdk1-cyclin B complexes. Moreover, exogenous expression of phosphotyrosine binding forms of PKM2 reversed the effects of PKM2 knock-down on G2-M arrest. We here show that PKM2 binds and stabilize otherwise transient pY15-containing Cdk1-cyclinB complexes that in turn facilitate Cdk1-cyclin B activation and entry of cells into mitosis. These results, therefore, establish metabolic enzyme PKM2 as a direct interactor and activator of Cdk1-cyclin B complex and thereby directly controls mitotic progression and the growth of brain tumor cells.

MRE11 and UBR5 Co-Operate to Suppress RNF168-Mediated Fusion of Dysfunctional Telomeres.

TRF2 is part of the shelterin complex that hides telomeric DNA ends and prevents the activation of the cNHEJ pathway that can lead to chromosomal fusion. TRF2, however, also actively suppresses the cNHEJ pathway by recruiting two proteins, MRE11 and UBR5. MRE11 binds BRCC3, which in turn deubiquitinates γH2AX deposited at exposed telomeric DNA ends and limits RNF168 recruitment to the telomere. UBR5, in contrast directly ubiquitinates and destroys RNF168. The loss of telomeric RNF168 in turn blocks the subsequent recruitment of 53BP1 and prevents the cNHEJ-mediated fusion of chromosomes with exposed telomeric DNA ends. Although MRE11 and UBR5 are both involved in the control of telomeric RNF168 levels and the chromosome fusion process, their relative contributions have not been directly addressed. To do so we genetically suppressed MRE11 and UBR5 alone or in combination in glioma cell lines which we previously showed contained dysfunctional telomeres that were dependent on TRF2 for suppression of telomeric fusion and monitored the effects on events associated with telomere fusion. We here show that while suppression of either MRE11 or UBR5 alone had minimal effects on RNF168 telomeric accumulation, 53BP1 recruitment, and telomeric fusion, their combined suppression led to significant increases in RNF168 and 53BP1 telomeric recruitment and telomeric fusion and eventually cell death, all of which were reversible by suppression of RNF168 itself. These results show that MRE11 and UBR5 co-operate to suppress fusion at dysfunctional telomeres.

RETRACTED: A subset of PARP inhibitors induces lethal telomere fusion in ALT-dependent tumor cells.

About 10% of all tumors, including most lower-grade astrocytoma, rely on the alternative lengthening of telomere (ALT) mechanism to resolve telomeric shortening and avoid limitations on their growth. Here, we found that dependence on the ALT mechanism made cells hypersensitive to a subset of poly(ADP-ribose) polymerase inhibitors (PARPi). We found that this hypersensitivity was not associated with PARPi-created genomic DNA damage as in most PARPi-sensitive populations but rather with PARPi-induced telomere fusion. Mechanistically, we determined that PARP1 was recruited to the telomeres of ALT-dependent cells as part of a DNA damage response. By recruiting MRE11 and BRCC3 to stabilize TRF2 at the ends of telomeres, PARP1 blocked chromosomal fusion. Exposure of ALT-dependent tumor cells to a subset of PARPi induced a conformational change in PARP1 that limited binding to MRE11 and BRCC3 and delayed release of the TRF2-mediated block on lethal telomeric fusion. These results therefore provide a basis for PARPi treatment of ALT-dependent tumors, as well as establish chromosome fusion as a biomarker of their activity.

A novel integrated system using patient-derived glioma cerebral organoids and xenografts for disease modeling and drug screening.

A physiologically relevant glioma tumor model is important to the study of disease progression and screening drug candidates. However, current preclinical glioma models lack the brain microenvironment, and the established tumor cell lines do not represent glioma biology and cannot be used to evaluate the therapeutic effect. Here, we reported a real-time integrated system by generating 3D ex vivo cerebral organoids and in vivo xenograft tumors based on glioma patient-derived tissues and cells. Our system faithfully recapitulated the histological features, response to chemotherapy drugs, and clinical progression of their corresponding parental tumors. Additionally, our model successfully identified a case from a grade II astrocytoma patient with typical grade IV GBM features in both organoids and xenograft models, which mimicked the disease progression of this patient. Further genomic and transcriptomic characterization was associated with individual clinical features. We have demonstrated the "GBM-&Normal-like" signature to predict prognosis. In conclusion, we developed an integrated system of parallel models from patient-derived glioma cerebral organoids and xenografts for understanding the glioma biology and prediction of response to chemotherapy drugs, which might lead to a new strategy for personalized treatment for this deadly disease.

High-Performance Zwitterionic Nanofiltration Membranes Fabricated via Microwave-Assisted Grafting of Betaine.

The thin-film composite (TFC) nanofiltration (NF) membrane is a very important method in solving the water crisis. However, the fabrication and industrialization of high-performance NF membranes still remains challenging. In this work, zwitterionic NF membranes via microwave-assisted grafting of betaine was first proposed. The resulting polyamide layer showed leaflike nanostructures after modification. Because of the enlarged permeation area and enhanced hydrophilicity derived from the unique leaflike structure, the optimal membrane permeability reached 40.8 L m-1 h-1 bar-1. This water permeance was 2.2 times as high as the original polypiperazine-amide membrane, with a Na2SO4 rejection maintained at 97.0%. More importantly, the membrane demonstrated excellent selectivity to monovalent and divalent anions. This zwitterionic membrane fabricated by microwave-assisted grafting of betaine provides new insight for industrial scalable NF membranes with great potentials.

Exosomal hsa-miR-21-5p derived from growth hormone-secreting pituitary adenoma promotes abnormal bone formation in acromegaly.

Growth hormone-secreting pituitary adenoma (GHPA), a benign endocrine tumor located in the base of the skull, results in acromegaly. In addition to the mass effect of the tumor itself in the sellar region, GHPA can lead to the overgrowth of almost every organ. Previous findings indicated that the processes underlying acromegaly were partly attributable to hyperactivity of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis. However, the mechanisms driving this syndrome remains largely unknown. Additionally, the roles of GHPA-derived exosomes, which contain functional microRNAs and proteins that manipulate target cell proliferation and differentiation in distal extremities, are also unknown. In this study, we demonstrated that GHPA exosomes promote bone formation in vitro and trabecula number in vivo. The mechanism of increased trabecula formation may be attributable to GHPA exosome-induced osteoblast proliferation via increased cell viability and DNA replication. We further discovered that exosomal hsa-miR-21-5p plays a distinct role from the GH/IGF-1 axis in these processes. Accordingly, the results of this study provide a novel mechanism whereby GHPA influences distal extremities and a new perspective for treating GHPA.

Fabriction of ZnO Nanorods with Strong UV Absorption and Different Hydrophobicity on Foamed Nickel under Different Hydrothermal Conditions.

ZnO nanorods have been grown on the surface of foamed nickel by a two-step method. Firstly, a layer of ZnO seed is sputtered on the surface of the foamed nickel by magnetron sputtering, and then the hydrothermal method is used to grow ZnO nanorods at different conditions (solution concentration, reaction time and reaction temperature). The results show that the morphology of ZnO nanorods is closely related to the solution concentration, reaction time, and reaction temperature. The energy band structure formed by the foamed nickel and ZnO seed layers and the growth mechanism of ZnO nanorods are discussed. The samples are characterized by Energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and Raman spectroscopy. The absorption characteristics of samples to light are characterized by ultraviolet-to-visible (UV⁻VIS) absorption. The hydrophilicity of the samples is characterized by the static contact angle. By analyzing the performance characteristics of the samples at different conditions, we finally obtained the optimal growth parameters. At the optimal parameters, the morphology of the grown nanorods is regular, the ultraviolet band has strong absorption, and the surface of the samples forms a superhydrophobic surface.

Fabrication of WO3·2H2O/BC Hybrids by the Radiation Method for Enhanced Performance Supercapacitors.

In this study, we described a facile process for the fabrication of tungsten oxide dihydrate/bamboo charcoal hybrids (WO3·2H2O/BC) by the γ-irradiation method. The structural, morphological, and electrochemical properties of WO3·2H2O/BC hybrids were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. The combination of BC (electrical double layer charge) and WO3·2H2O (pseudocapacitance) created a combined effect, which enhanced the specific capacitance and superior cyclic stability of the WO3·2H2O/BC hybrid electrode. The WO3·2H2O/BC hybrids showed the higher specific capacitance (391 F g-1 at 0.5 A g-1 over the voltage range from -1 to 0 V), compared with BC (108 F g-1) in 6 M KOH solution. Furthermore, the hybrid electrode showed superior long-term performance with 82% capacitance retention even after 10,000 cycles. The experimental results demonstrated that the high performance of WO3·2H2O/BC hybrids could be a potential electrode material for supercapacitors.

A Novel Radiation Method for Preparing MnO2/BC Monolith Hybrids with Outstanding Supercapacitance Performance.

A novel facile process for fabrication of amorphous MnO2/bamboo charcoal monolith hybrids (MnO2/BC) for potential supercapacitor applications using γ-irradiation methods is described. The structural, morphological and electrochemical properties of the MnO2/BC hybrids have been investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. The combination of BC (electrical double layer charge) and MnO2 (pseudocapacitance) created a complementary effect, which enhanced the specific capacitance and good cyclic stability of the MnO2/BC hybrid electrodes. The MnO2/BC hybrids showed a higher specific capacitance (449 F g-1 at the constant current density of 0.5 A g-1 over the potential range from ⁻0.2 V to 0.8 V), compared with BC (101 F g-1) in 1 M of Na2SO4 aqueous electrolyte. Furthermore, the MnO2/BC hybrid electrodes showed superior cycling stability with 78% capacitance retention, even after 10,000 cycles. The experimental results demonstrated that the high performance of MnO2/BC hybrids could be a potential electrode material for supercapacitors.

Fibroblasts play a potential role in bone destruction via osteopontin related caldesmon expression and polymerization in human non-functioning pituitary adenomas.

Non-functioning pituitary adenomas (NFPAs) are the most frequent pituitary tumors. The elucidation of the mechanisms of aggressive NFPAs in bone destruction is required in order to guide the clinical diagnosis and treatment of NFPAs. In the present study, we investigated the differential proteomics of fibroblasts isolated from clinical specimens of NFPAs with or without bone destruction. Proteomic analysis revealed a group of molecules associated with cytoskeleton organization, including caldesmon, were differentially expressed between fibroblasts isolated from bone destruction NFPAs (BD-NFPAs) and fibroblasts isolated from non-bone destruction NFPAs (NBD-NFPAs). The secreted proteins analysis found that osteopontin was significantly upregulated in BD-NFPAs fibroblasts. Furthermore, immunohistochemical staining of the NFPAs clinical samples showed that the expression of caldesmon in stromal cells and the expression of osteopontin in both tumor cells and stroma were significantly increased in BD-NFPAs. Taken together, our results indicate a possible way that osteopontin secreted from both NFPA cells and surrounding fibroblasts modify caldesmon expression and polymerization in fibroblasts, which may contribute to bone destruction in NFPA patients.

Polypiperazine-amide Nanofiltration Membrane Modified by Different Functionalized Multiwalled Carbon Nanotubes (MWCNTs).

In this work, three modified multiwalled carbon nanotubes (MWCNTs) with carboxyl (MWCNT-COOH), hydroxyl (MWCNT-OH) and amino groups (MWCNT-NH), respectively, were added into the aqueous phase containing piperazine (PIP) to fabricate the nanocomposite nanofiltration (NF) membranes via interfacial polymerization. The influences of functional groups of MWCNTs on the performance of modified NF membrane were investigated. The MWCNTs were characterized by TEM, FT-IR and TGA; meanwhile, the properties of the membranes were evaluated by XPS, TEM, AFM and contact angle. The XPS results proved the successful incorporation of MWCNT in the active layer of modified NF membrane. When the MWCNT concentration is 0.01% (w/v), all the nanocomposite membranes possessed the optimal separation properties, among which the membrane incorporated with MWCNT-OH demonstrated the highest water flux of 41.4 L·m(-2)·h(-1) and the Na2SO4 rejection of 97.6% whereas the one with MWCNT-COOH had the relative lowest rejection of 96.6%. Furthermore, the increased hydrophilicity of functional groups in modified MWCNTs resulted in different nodular surface morphologies, thicknesses and hydrophilicities of the nanocomposite membranes. All the membranes possessed a molecular weight cutoff (MWCO) within 300 Da and good operation stability.