MRI-guided neutron capture therapy by use of a dual gadolinium/boron agent targeted at tumour cells through upregulated low-density lipoprotein transporters

The upregulation of low-density lipoprotein (LDL) transporters in tumour cells has been exploited to deliver a sufficient amount of gadolinium/boron/ligand (Gd/B/L) probes for neutron capture therapy, a binary chemio-radiotherapy for cancer treatment. The Gd/B/L probe consists of a carborane unit (ten B atoms) bearing an aliphatic chain on one side (to bind LDL particles), and a Gd(III)/1,4,7,10-tetraazacyclododecane monoamide complex on the other (for detection by magnetic resonance imaging (MRI)). Up to 190 Gd/B/L probes were loaded per LDL particle. The uptake from tumour cells was initially assessed on cell cultures of human hepatoma (HepG2), murine melanoma (B16), and human glioblastoma (U87). The MRI assessment of the amount of Gd/B/L taken up by tumour cells was validated by inductively coupled plasma-mass-spectrometric measurements of the Gd and B content. Measurements were undertaken in vivo on mice bearing tumours in which B16 tumour cells were inoculated at the base of the neck. From the acquisition of magnetic resonance images, it was established that after 4-6 hours from the administration of the Gd/B/L-LDL particles (0.1 and 1 mmol kg(-1) of Gd and (10)B, respectively) the amount of boron taken up in the tumour region is above the threshold required for successful NCT treatment. After neutron irradiation, tumour growth was followed for 20 days by MRI. The group of treated mice showed markedly lower tumour growth with respect to the control group.     

Isoginkgetin—A Natural Compound to Control U87MG Glioblastoma Cell Growth and Migration Activating Apoptosis and Autophagy

Isoginkgetin (Iso) is a natural bioflavonoid isolated from the leaves of Ginkgo biloba, this natural substance exhibits many healing properties, among which the antitumor effect stands out. Here we tested the effect of Iso on the growth of U87MG glioblastoma cells. Growth curves and MTT toxicity assays showed time and dose-dependent growth inhibition of U87MG after treatment with Iso (15/25 µM) for 1, 2, and 3 days. The cell growth block of U87MG was further investigated with the colony formation test, which showed that iso treatment for 24 h reduced colony formation. The present study also aimed to evaluate the effect of Iso on U87MG glioblastoma cell migration. The FACS analysis, on the other hand, showed that treatment with Iso 15 µM determines a blockage of the cell cycle in the S1 phase. Further investigation shows that Iso treatment of U87MG altered the protein pathways of homeostasis including autophagy and apoptosis. The present study demonstrated, for the first time, that Iso could represent an excellent adjuvant drug for the treatment of glioblastoma by simultaneously activating multiple mechanisms that control the growth and migration of neoplastic cells.     

Catanionic solid lipid nanoparticles carrying doxorubicin for inhibiting the growth of U87MG cells

Catanionic solid lipid nanoparticles (CASLNs), loaded with doxorubicin (Dox) and grafted with anti-epithelial growth factor receptor (EGFR) (anti-EGFR/Dox-CASLNs), were applied to suppressing propagation of malignant U87MG cells. U87MG cells were cultured with anti-EGFR/Dox-CASLNs for assessing the cell viability and EGFR expression. When the concentration of catanionic surfactants, containing hexadecyltrimethylammonium bromide and sodium anionic sodium dodecylsulfate, was 1mM, CASLNs entrapped the largest quantity of Dox. The order of cacao butter (CB) in the entrapment efficiency of Dox was 50% CB>0% CB>100% CB. In addition, the release rate of Dox and the antiproliferative effect on U87MG cells were in the following order: 100% CB>0% CB>50% CB. A high level of CB in anti-EGFR/Dox-CASLNs reduced the cytotoxicity to human brain-microvascular endothelial cells. The immunochemical staining revealed that the crosslinked anti-EGFR on the surface of Dox-CASLNs preserved a high specificity in recognizing EGFR on U87MG cells and inducing growth-inhibition effect. The innovated anti-EGFR/Dox-CASLNs can be an effective delivery system with high targeting efficacy against the growth of brain glioblastomas carcinoma.     

The preparation and thermoelectric properties of molten salt electrodeposited boron wafers

We have prepared electrodeposited boron wafer by molten salts with KBF₄-KF at 680°C using graphite crucible for anode and silicon wafer and nickel plate for cathodes. Experiments were performed by various molar ratios KBF₄/KF and current densities. Amorphous p-type boron wafers with purity 87% was deposited on nickel plate for 1 h. Thermal diffusivity by ring-flash method and heat capacity by DSC method produced thermal conductivity showing amorphous behavior in the entire temperature range. The systematical results on thermoelectric properties were obtained for the wafers prepared with KBF₄-KF (66-34 mol%) under various current densities in the range 1-2 A/cm². The temperature dependencies of electrical conductivity showed thermal activated type with activation energy of 0.5 eV. Thermoelectric power tended to increase with increasing temperature up to high temperatures with high values of (1-10) mV/K. Thermoelectric figure-of-merit was 10⁻⁴/K at high temperatures. Estimated efficiency of thermoelectric energy conversion would be calculated to be 4-5%.     

Voltammetry and controlled-potential coulometry with boron carbide electrodes

With the boron carbide electrode, E_{p$\text{p}\text{2}$} values were determined for the reduction of the following ions: Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II), Ru(IV), Sb(V), and U(VI). The linear dependence of peak current on concentration is demonstrated for the U(VI) → U(IV) and Fe(III) → Fe(II) reductions at the boron carbide electrode. The suitability of the electrode for the controlled-potential coulometric ti trations of Fe(II) → Fe(III), Fe(III) → Fe(II), and U(VI) → U(IV) was studied; the results were inconclusive because of the small surface area that could be used conveniently and the possibility of oxygen leaks in the cell.     

Wnt/GSK3β/β-catenin signaling pathway regulates calycosin-mediated anticancer effects in glioblastoma multiforme cells

Calycosin, an O-methylated isoflavone, has been widely reported to induce anticancer activity in different cancer cells in vitro. Nonetheless, the associated mechanism of calycosin in glioblastoma multiforme cells (U87) still remains unknown. To explore the anticancer effects, the apoptotic mechanism of calycosin via Wnt/GSK3β/β-catenin signaling was explored in U87 cells. Different assays including: cytotoxicity, free radical determination, SOD and CAT activity, GSH content, qPCR, mitochondrial membrane potential, caspase activity, and western blotting assays were performed. It was shown that calycosin mitigated cell viability in U87 cells, whereas it showed no apparent effect on BV2 microglial cells. Calycosin triggered apoptosis via upregulating the mitochondria-associated caspase pathway in U87 cells. Calycosin induced the reduction of the mitochondrial membrane potential, overexpression of Bax, downexpression of Bcl-2, and activation of caspase-9 and caspase-3. Calycosin-stimulated apoptosis was associated with the upregulation of free radical scavenging through the modulation of antioxidant enzymes, such as SOD and CAT as well as the level of GSH. The apoptotic activity of calycosin was mediated by suppression of pGSK-3βser9, β-catenin, and c-Myc at protein level. The present study suggested that calycosin triggers U87 cell death through an antioxidant effect mediated by Wnt/GSK3β/β-catenin signaling pathway.     

Harnessing the Potential Synergistic Interplay Between Photosensitizer Dark Toxicity and Chemotherapy

The combination of photodynamic therapy and taxol- or platinum-based chemotherapy (photochemotherapy) is an effective and promising cancer treatment. While the mechanisms of action of photochemotherapy are actively studied, relatively little is known about the cytotoxicity and molecular alterations induced by the combination of chemotherapy and photosensitizers without light activation in cancer cells. This study investigates the interplay between the photosensitizer benzoporphyrin derivative (BPD) without light activation and cisplatin or paclitaxel in two glioblastoma lines, U87 and U251. The combination effect of BPD and cisplatin in U87 cells is slightly synergistic (combination index, CI = 0.93), showing 1.8- to 2.6-fold lower half-maximal inhibitory concentrations (IC₅₀) compared to those of individual drugs. In contrast, combining BPD and paclitaxel is slightly antagonistic (CI = 1.14) in U87 cells. In U251 cells, the combinations of BPD and cisplatin or paclitaxel are both antagonistic (CI = 1.24 and 1.34, respectively). Western blotting was performed to investigate changes in the expression levels of YAP, TAZ, Bcl-2 and EGFR in U87 and U251 cells treated with BPD, cisplatin and paclitaxel, both as monotherapies and in combination. Our study provides insights into the molecular alterations in two glioma lines caused by each monotherapy and the combinations, in order to inform the design of effective treatments.     

激光-时间分辨荧光法测定U3O8中痕量硼

本文提出了一种测定U3O8中痕量硼的激光-时间分辨荧光法, 在适当介质中, 用小型氮分子激光器激发硼与二苯甲酰基甲烷配合物的荧光, 发现此配合物的荧光寿命为2ms, 它比铀的荧光寿命长得多, 从而可将荧光的时间分辨技术应用于铀中硼的测定, 不经分离基体铀即可进行测定, 方法简单而快速, 检测下限达到0.02ng.mL^-^1(硼),当取样10mg铀时, 能测定0.01ppm的硼。用本法分析了含量在0.04-0.5ppm几个U3O8样品, 结果与其他方法相符。     

Photodynamic Therapy of Human Glioma (U87) in the Nude Rat

Abstract— We measured the response of normal brain and the human U87 glioma implanted in the brain of rats (n = 65) to photodynamic therapy (PDT) using Photofrin as the sensitizer. Normal brain and U87 tumor implanted within brain of athymic (nude) rats were subjected to PDT (12.5 mg/kg of Photofrin) at increasing optical energy doses (35 J/cm², 140 J/cm², 280 J/cm²) of 632 nm light. Photofrin concentration in tumor, brain adjacent to tumor and normal brain were measured in a separate population of rats. Twenty-four hours after PDT, the brains were removed, sectioned, stained with hematoxylin and eosin (H&E), and the volumes of the PDT-induced lesion measured. Photofrin concentration in tumor greatly exceeded that of normal brain and brain adjacent to tumor (>20×). Both normal brain and U87 tumor exhibited superficial tissue damage with PDT at 35 J/cm². However, both normal and tumor-implanted brain exhibited tissue damage with increasing optical dose. A heterogeneous pattern of pannecrosis along with a uniform volume of pannecrosis was detected in the tumor. In contrast, normal brain exhibited a uniform sharply demarcated volume of necrosis. Our data indicate that the U87 human brain tumor model and the normal brain in the athymic rat are sensitive to PDT and Photofrin with an optical dose-dependent response to treatment.     

Strengthening Anti-Glioblastoma Effect by Multi-Branched Dendrimers Design of a Scorpion Venom Tetrapeptide

Glioblastoma is the most aggressive and invasive form of central nervous system tumors due to the complexity of the intracellular mechanisms and molecular alterations involved in its progression. Unfortunately, current therapies are unable to stop its neoplastic development. In this context, we previously identified and characterized AaTs-1, a tetrapeptide (IWKS) from Androctonus autralis scorpion venom, which displayed an anti-proliferative effect against U87 cells with an IC₅₀ value of 0.57 mM. This peptide affects the MAPK pathway, enhancing the expression of p53 and altering the cytosolic calcium concentration balance, likely via FPRL-1 receptor modulation. In this work, we designed and synthesized new dendrimers multi-branched molecules based on the sequence of AaTs-1 and showed that the di-branched (AaTs-1-2B), tetra-branched (AaTs-1-4B) and octo-branched (AaTs-1-8B) dendrimers displayed 10- to 25-fold higher effects on the proliferation of U87 cells than AaTs-1. We also found that the effects of the newly designed molecules are mediated by the enhancement of the ERK1/2 and AKT phosphorylated forms and by the increase in p53 expression. Unlike AaTs-1, AaTs-1-8B and especially AaTs-1-4B affected the migration of the U87 cells. Thus, the multi-branched peptide synthesis strategy allowed us to make molecules more active than the linear peptide against the proliferation of U87 glioblastoma cells.     

Microbicide Containing Ellagic Acid Can Inhibit HIV-1 Infection

Objectives: Ellagic acid (EA) has a wide range of biological effects. The purpose of this study was to investigate the in vitro effects of EA on HIV-1 replication, viral enzyme activity and cytokine secretion by infected cells. Methods: The anti-HIV-1 activity of EA in solution was determined in vitro using the infection of TZM-bl cells by the nano luciferase-secreting R5-tropic JRCSF strain of HIV-1, which allows for the quantification of viral growth by measuring nano luciferase in the culture supernatants. The effect of EA on the cytokine secretion of TZM-bl cells was determined by a multiplexed bead array after 48 h of HIV-1 exposure. The antiviral effect of EA in the gel formulation (Ellagel), as would be used for vaginal application, was investigated by the inhibition of infection of UC87.CD4.CCR5 cells with R5-tropic pBaLEnv-recombinant HIV-1. Results: EA in solutions of up to 100 µM was not toxic to TZM-bl cells. EA added either 1 h before or 4 h after HIV-1 exposure suppressed the replication of R5-tropic HIV-1 in TZM-bl cells in a dose-dependent manner, with up to 69% inhibition at 50 µM. EA-containing solutions also exhibited a dose-dependent inhibitory effect on HIV-1 replication in U87 cells. When EA was formulated as a gel, Ellagel containing 25 µM and 50 µM EA inhibited HIV-1 replication in U87 cells by 56% and 84%, respectively. In assays of specific HIV-1 enzyme activity, Ellagel inhibited HIV-1 integrase but not protease. EA did not significantly modulate cytokine secretion. Conclusions: We conclude that EA either in solution or in a gel form inhibits HIV infection without adverse effects on target cells. Thus, gel containing EA can be tested as a new microbicide against HIV infection.     

Structure and stability of small boron and boron oxide clusters

To rationally design and explore a potential energy source based on the highly exothermic oxidation of boron, density functional theory (DFT) was used to characterize small boron clusters with 0-3 oxygen atoms and a total of up to ten atoms. The structures, vibrational frequencies, and stabilities were calculated for each of these clusters. A quantum molecular dynamics procedure was used to locate the global minimum for each species, which proved to be crucial given the unintuitive structure of many of the most stable isomers. Additionally, due to the plane-wave, periodic DFT code used in this study a straightforward comparison of these clusters to the bulk boron and B2O3 structures was possible despite the great structural and energetic differences between the two forms. Through evaluation of previous computational and experimental work, the relevant low-energy structures of all but one of the pure boron clusters can be assigned with great certainty. Nearly all of the boron oxide clusters are described here for the first time, but there are strong indications that the DFT procedure chosen is particularly well suited for the task. Insight into the trends in boron and boron oxide cluster stabilities, as well as the ultimate limits of growth for each, are also provided. The work reported herein provides crucial information towards understanding the oxidation of boron at a molecular level.     

Green synthesis of Zn nanoparticles and in situ hybridized with BSA nanoparticles for Baicalein targeted delivery mediated with glutamate receptors to U87-MG cancer cell lines

Glioblastoma multiforme (GBM) is the most aggressive malignant tumor of the brain. It has different glutamate receptor types. So, these receptors can be a suitable target for GBM treatment. The current study investigated the anticancer effects of bovine serum albumin (BSA)-Baicalein @Zn-Glu nanostructure mediated-GluRs in human glioblastoma U87 cells. BSA-Ba@Zn-Glu hybrid nanoparticles (NPs) were set and considered transporters for Baicalein (Ba) active compound delivery. BSA-Ba@Zn-Glu NPs were synthesized by a single-step reduction process. The successful production was confirmed through transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), and hemolysis test. The cytotoxic efficacy and apoptosis rate of the nanostructures on U87 glioblastoma cells were investigated by 3-(4,5-dimethylthialzol-a-yl)-2,5 diphenyltetrazolium bromide (MTT) and flow cytometry assays, respectively. The synthesized BSA-Ba@Zn-Glu nanostructures with a diameter of 142.40 ± 1.91 to 177.10 ± 1.87 nm and zeta potential of −10.57 ± 0.71 to −35.77 ± 0.60 mV are suitable for extravasation into tumor cells. The drug release from the BSA-Ba@Zn NPs showed controlled and pH-dependent behavior. In vitro results indicated that the BSA-Ba@Zn-Glu NPs significantly reduce cell viability and promote apoptosis of U87 cancer cells. It revealed the cytotoxic effect of the Baicalein and an increase in cellular uptake of nanoparticles by Glu receptors. Zn NPs were synthesized based on a green synthesis method. BSA NPs were used as a nano-platform for Glu conjugation and Ba drug delivery. BSA-Ba@Zn-Glu NPs induce cytotoxicity and apoptosis in human brain cancer cells (U87) in a dose-dependent manner. Finally, this nanostructure could be served in targeted drug delivery in vivo studies and applied along with other strategies such as X-ray irradiation as combinational therapies in future studies.     

99mTc-radiolabeled imidazo[2,1-b]benzothiazole derivatives as potential radiotracers for glioblastoma

This study presents [^99mTc]BPTG-1 and [^99mTc]BPTG-2 for glioblastoma imaging. In vitro cellular uptakes of these radiotracers were examined in SKOV-3, MCF-7, U87-MG, HT-29, and A549 cell lines. U87-MG cell line displayed the highest radiotracers uptakes. Biodistribution study in U87-MG tumor bearing mice revealed higher uptake of radiotracers in tumor than muscle and brain. Liver, intestine, and kidneys displayed the highest radioactivity uptakes. The main route of radiotracers elimination was hepatobiliary. Due to the brain uptake of these radiotracers, they are promising radiotracers for future studies in the diagnosis of glioblastoma.

     

Choice of boron shield in epithermal neutron activation determinations

Boron trioxide, boron nitride, boron carbide and elemental boron giving different boron surface densities have been used as neutron shields in epithermal neutron activation determinations. Boron ratios and advantage factors for 29 nuclides have been determined. A new expression of the advantage factor has been derived from statistics of radioactive decay viewpoint. A real improvement, in comparison with classical neutron activation methods, can be obtained for the determination of As, Br, Cd, I, Mo. Sb, Sn, Th, W and U by use of boron shields.     

Direct fluorescence monitoring of the delivery and cellular uptake of a cancer-targeted RGD peptide-appended naphthalimide theragnostic prodrug

Presented here is a multicomponent synthetic strategy that allows for the direct, fluorescence-based monitoring of the targeted cellular uptake and release of a conjugated therapeutic agent. Specifically, we report here the design, synthesis, spectroscopic characterization, and preliminary in vitro biological evaluation of a RGD peptide-appended naphthalimide pro-CPT (compound 1). Compound 1 is a multifunctional molecule composed of a disulfide bond as a cleavable linker, a naphthalimide moiety as a fluorescent reporter, an RGD cyclic peptide as a cancer-targeting unit, and camptothecin (CPT) as a model active agent. Upon reaction with free thiols in aqueous media at pH 7.4, disulfide cleavage occurs. This leads to release of the free CPT active agent, as well as the production of a red-shifted fluorescence emission (λ(max) = 535 nm). Confocal microscopic experiments reveal that 1 is preferentially taken up by U87 cells over C6 cells. On the basis of competition experiments involving okadaic acid, an inhibitor of endocytosis, it is concluded that uptake takes place via RGD-dependent endocytosis mechanisms. In U87 cells, the active CPT payload is released within the endoplasmic reticulum, as inferred from fluorescence-based colocalization studies using a known endoplasmic reticulum-selective dye. The present drug delivery system (DDS) could represent a new approach to so-called theragnostic agent development, wherein both a therapeutic effect and drug uptake-related imaging information are produced and can be readily monitored at the subcellular level. In due course, the strategy embodied in conjugate 1 could allow for more precise monitoring of dosage levels, as well as an improved understanding of cellular uptake and release mechanisms.     

Photodynamic Efficacy of Cercosporin in 3D Tumor Cell Cultures

In the present work, we study the photodynamic action of cercosporin (cerco), a naturally occurring photosensitizer, on human cancer multicellular spheroids. U87 spheroids exhibit double the uptake of cerco than T47D and T98G spheroids as shown by flow cytometry on the single cell level. Moreover, cerco is efficiently internalized by cells throughout the spheroid as shown by confocal microscopy, for all three cell lines. Despite their higher cerco uptake, U87 spheroids show the least vulnerability to cerco-PDT, in contrast to the other two cell lines (T47D and T98G). While 300 μm diameter spheroids consistently shrink and become necrotic after cerco PDT, bigger spheroids (>500 μm) start to regrow following blue-light PDT and exhibit high viability. Cerco-PDT was found to be effective on bigger spheroids reaching 1mm in diameter especially under longer exposure to yellow light (~590 nm). In terms of metabolism, T47D and T98G undergo a complete bioenergetic collapse (respiration and glycolysis) as a result of cerco-PDT. U87 spheroids also experienced a respiratory collapse following cerco-PDT, but retained half their glycolytic activity.     

Monitoring the Glutathione Redox Reaction in Living Human Cells by Combining Metabolic Labeling with Heteronuclear NMR

The glutathione (GSH) redox reaction is critical for defense against cellular reactive oxygen species (ROS). However, direct and real‐time monitoring of this reaction in living mammalian cells has been hindered by the lack of a facile method. Herein, we describe a new approach that exploits the GSH biosynthetic pathway and heteronuclear NMR. [U‐¹³C]‐labeled cysteine was incorporated into GSH in U87 glioblastoma cells, and the oxidation of GSH to GSSG by a ROS‐producing agent could be monitored in living cells. Further application of the approach to cells resistant to temozolomide (TMZ), an anti‐glioblastoma drug, suggested a possible new resistance mechanism involving neutralization of ROS. This result was corroborated by the observation of up‐regulation of glutathione peroxidase 3 (GPx3). This new approach could be easily applied to redox‐dependent signaling pathways and drug resistance involving ROS.     

Controllable Assembly and Properties of Brain Targeting Peptides with Tetrahedral Framework Nucleic Acids北大核心CSCD

In this study,the armed tetrahedral DNA nanostructures（TDN）are designed to bind single or three complementary strands of armed chain（1-ANG-TDN,3-ANG-TDN）which is modified with angiopep-2 or other brain targeting peptides（TAT,TGN）. We compare the cell viability and cellular uptake of 1-ANG-TDN or 3-ANG-TDN in brain capillary endothelial（bEnd. 3）cells and Uppsala 87 malignant glioma（U87） cells. In addition,the cell viability and cellular uptake of ANG-TDN,TAT-TDN and TGN-TDN in bEnd. 3 cells are investigated respectively. The results show that these probes are not cytotoxic to bEnd. 3 cells and U87 cells at concentrationsbelow 100 nmol/L. After being incubated with bEnd. 3cells for 0. 5 h,the cellular uptake of 3-ANG-TDN is higher than that of 1-ANG-TDN（P<0. 01）. After being incubated with U87 cells for 1h,the cellular uptake of 3-ANG-TDN is higher than that of 1-ANG-TDN（P<0. 01）. After 2 h,there is no obvious difference in cellular uptake between 1-ANG-TDN and 3-ANG-TDN. ANG-TDN,TAT-TDN and TGN-TDN are up-taken by bEnd. 3 cells much more than TDN（P<0. 01）. However,there isno statistical difference among ANG-TDN,TAT-TDN and TGN-TDN（P>0. 05）. These results indicate that the targeting of ANG-TDN probe can be improved by increasing the number of peptides or prolonging the co-incubation time. This discovery providesareference for the multifunctional modification of tetrahedral framework nucleic acid. When a single peptidelinked with TDN achieves the brain targeting,other sites of TDN can be modified by other functional groups to expand the structure and function. Tetrahedral framework nucleic acids can be used not only as an assembly platform for ANG peptides,but also for the assembly of other brain-targeting peptides （TAT and TGN）to design brain-targeting probes. © 2022, Science Press (China). All rights reserved.