Terbium-Rose Bengal Coordination Nanocrystals-Induced ROS Production under Low-Dose X-rays in Cultured Cancer Cells for Photodynamic Therapy.

X-ray-triggered scintillators (Sc) and photosensitizers (Ps) have been developed for X-ray-induced photodynamic therapy (X-PDT) to selectively destruct deep tissue tumors with a low X-ray dose. This study designed terbium (Tb)-rose bengal (RB) coordination nanocrystals (T-RBNs) by a solvothermal treatment, aiming to reduce photon energy dissipation between Tb3+ and RB and thus increase the reactive oxygen species (ROS) production efficiency. T-RBNs synthesized at a molar ratio of [RB]/[Tb] = 3 exhibited a size of 6.8 ± 1.2 nm with a crystalline property. Fourier transform infrared analyses of T-RBNs indicated successful coordination between RB and Tb3+. T-RBNs generated singlet oxygen (1O2) and hydroxyl radicals (•OH) under low-dose X-ray irradiation (0.5 Gy) via scintillating and radiosensitizing pathways. T-RBNs produced ∼8-fold higher ROS amounts than bare RB and ∼3.6-fold higher ROS amounts than inorganic nanoparticle-based controls. T-RBNs did not exhibit severe cytotoxicity up to 2 mg/mL concentration in cultured luciferase-expressing murine epithelial breast cancer (4T1-luc) cells. Furthermore, T-RBNs were efficiently internalized into cultured 4T1-luc cells and induced DNA double strand damage, as evidenced by an immunofluorescence staining assay with phosphorylated γ-H2AX. Ultimately, under 0.5 Gy X-ray irradiation, T-RBNs induced >70% 4T1-luc cell death via simultaneous apoptosis/necrosis pathways. Overall, T-RBNs provided a promising Sc/Ps platform under low-dose X-PDT for advanced cancer therapy.

Rose Bengal Decorated NaYF4:Tb Nanoparticles for Low Dose X-ray-Induced Photodynamic Therapy in Cancer Cells.

The use of scintillating nanoparticles (ScNPs) in X-ray-induced photodynamic therapy (X-PDT) is a technique for deep tissue-localized tumor therapy with few side effects. ScNPs transfer X-ray-induced energy to photosensitizers, which generate massive amounts of reactive oxygen species (ROS) and kill cancer cells. Here we fabricated rose bengal (RB)-installed, Tb3+-rich NaYF4 nanocrystals (NaYF4:Tb@RB), in which optically inert Y3+ enables highly efficient energy transfer via high amounts of Tb3+ doping. NaYF4:Tb was prepared via solvothermal synthesis to have an average size of 7.6 nm, followed by coating with poly(maleic anhydride-alt-1-octedecene)-poly(ethylene glycol) with a molecular weight of 2000 (C18PMH-PEG2k). Further, RB was covalently conjugated to carboxyl groups generated from PMH on NaYF4:Tb using an ethylenediamine linker. NaYF4:Tb@RB exhibited a hydrodynamic diameter of ∼75 nm with a ζ-potential of -12 mV. NaYF4:Tb@RB efficiently generated ROS in cultured luciferase-expressing murine epithelial breast cancer (4T1-luc) cells under low dose X-ray irradiation (0.5 Gy). The ROS generation amounts of NaYF4:Tb@RB were 1.5-2-fold higher than those of NaGdF4:Tb@RB, in which host nanocrystals were prepared with optically active Gd3+. Flow cytometric and confocal microscopic analyses showed higher intracellular ROS production of NaYF4:Tb@RB, compared to NaYF4:Tb and RB, resulting in higher X-ray-induced DNA damage in cultured 4T1-luc cells. Ultimately, NaYF4:Tb@RB elicited significant cytotoxicity after X-ray irradiation (0.5 Gy), while inducing marginal cytotoxicity without X-ray irradiation. Altogether, this research proposes a promising ScNP design for efficient X-PDT agents that make the better use of incident X-ray energy while causing the fewest side effects.

Effects of Oxygen Gas Injection on the Subsequent Development of Chick Embryos in a Shell-Less Culture System.

The effects of oxygen gas injection starting on day 17 of incubation (D17) in a chick shell-less culture system (cSLC) on the subsequent embryo development were examined on day 19 of incubation (D19). On D19 of cSLC, the plasma phosphorus and total cholesterol concentrations of the embryos were significantly higher (P<0.05), while the plasma calcium concentrations were significantly lower (P<0.05) than those in the intact control (IC) group. However, no significant differences in embryo viability and other major blood component levels were observed among the experimental groups (P>0.05). The percutaneous oxygen saturation was lower in D17-cSLC embryos before oxygen gas supplementation than in the IC (P<0.05) embryos. Severe renal tubular degeneration of the metanephros was observed in D19-cSLC embryos despite oxygen gas injection starting from D17. These results indicate that D19-cSLC embryos are hypoxia even after injecting oxygen gas starting on D17.

Effects of Calcium Lactate on the Development of Chicken Embryos in a Shell-less Culture System up to Day Seventeen of Incubation.

This study examined the effects of calcium lactate on the development of chicken embryos in a shell-less culture system (cSLCS) up to the seventeenth day of incubation. In the presence of calcium lactate, a significant reduction in embryo viability was observed during the first week of incubation in cSLCS. On day 17 of embryo development, no significant difference was observed in the blood plasma calcium concentration or tibia bone density between cSLCS and intact control embryos, whereas the tibia length was significantly shorter in cSLCS embryos than in the intact control. These results suggest that calcium lactate supplementation in cSLCS supports bone formation in developing chicken embryos, but has adverse effects on the viability of embryos, particularly during the first week of embryo development.

Structural tuning of oligonucleotides for enhanced blood circulation properties of unit polyion complexes prepared from two-branched poly(ethylene glycol)-block-poly(l-lysine).

Downsizing nanocarriers is a promising strategy for systemically targeting fibrotic cancers, such as pancreatic cancer, owing to enhanced tissue permeability. We recently developed a small oligonucleotide nanocarrier called a unit polyion complex (uPIC) using a single oligonucleotide molecule and one or two molecule(s) of two-branched poly(ethylene glycol)-b-poly(l-lysine) (bPEG-PLys). The uPIC is a dynamic polyion-pair equilibrated with free bPEG-PLys, and thus, is highly stabilized in the presence of excess amounts of free bPEG-PLys in the bloodstream. However, the dynamic polyion-pairing behavior of uPICs needs to be further investigated for longevity in the bloodstream, especially under lower amounts of free bPEG-PLys. Herein, the polyion-pairing behavior of uPICs was investigated by highlighting oligonucleotide stability and negative charge number. To this end, small interfering RNA (siRNA) and antisense oligonucleotides (ASO) were chemically modified to acquire nuclease resistance, and the ASO was hybridized with complementary RNA (cRNA) to form a hetero-duplex oligonucleotide (HDO) with twice the negative charges. While all oligonucleotides similarly formed sub-20 nm-sized uPICs from a single oligonucleotide molecule, the association number of bPEG-PLys (ANbPEG-PLys) in uPICs varied based on the negative charge number of oligonucleotides (N-), that is, ANbPEG-PLys = ~2 at N- = ~40 (i.e., siRNA and HDO) and ANbPEG-PLys = ~1 at N- = 20 (i.e., ASO), presumably because of the balanced charge neutralization between the oligonucleotide and bPEG-PLys with a positive charge number (N+) of ~20. Ultimately, the uPICs prepared from the chemically modified oligonucleotide with higher negative charges showed considerably longer blood retention than those from the control oligonucleotides without chemical modifications or with lower negative charges. The difference in the blood circulation properties of uPICs was more pronounced under lower amounts of free bPEG-PLys. These results demonstrate that the chemical modification and higher negative charge in oligonucleotides facilitated the polyion-pairing between the oligonucleotide and bPEG-PLys under harsh biological conditions, facilitating enhanced blood circulation of uPICs.

Targeting the Notch-regulated non-coding RNA TUG1 for glioma treatment.

Targeting self-renewal is an important goal in cancer therapy and recent studies have focused on Notch signalling in the maintenance of stemness of glioma stem cells (GSCs). Understanding cancer-specific Notch regulation would improve specificity of targeting this pathway. In this study, we find that Notch1 activation in GSCs specifically induces expression of the lncRNA, TUG1. TUG1 coordinately promotes self-renewal by sponging miR-145 in the cytoplasm and recruiting polycomb to repress differentiation genes by locus-specific methylation of histone H3K27 via YY1-binding activity in the nucleus. Furthermore, intravenous treatment with antisense oligonucleotides targeting TUG1 coupled with a drug delivery system induces GSC differentiation and efficiently represses GSC growth in vivo. Our results highlight the importance of the Notch-lncRNA axis in regulating self-renewal of glioma cells and provide a strong rationale for targeting TUG1 as a specific and potent therapeutic approach to eliminate the GSC population.

ephA9, a novel avian receptor tyrosine kinase gene.

Protein tyrosine kinase (TK) receptors are known to play crucial roles in various aspects of normal development and in tumorigenesis. Germ cells before their colonizing to the gonads during embryogenesis are called primordial germ cells (PGCs). To identify TK genes expressed in chicken PGCs, we purified these cells from the blood of 2.5-day-old embryos, extracted the polyA(+) RNA, and subjected it to reverse transcription-polymerase chain reaction (RT-PCR) amplification with TK gene-specific primers. As a result, we identified 13 receptor TK genes and 6 non-receptor TK genes. One of the receptor TK genes appeared to be novel, and thus the full-length DNA complementary to RNA (cDNA) sequence was retrieved by the rapid cloning of cDNA ends method. Sequence analysis of this cDNA indicated that it encoded a novel TK receptor of the Eph family. The putative amino-acid sequence of this TK was 63.0% identical to that of human EphA1; therefore, we designated our novel TK as EphA9. Northern blot hybridizations indicated that ephA9 RNA transcripts were present in the kidney, lung, testis, and thymus but not in the spleen, brain, or liver. Expression of a fusion protein containing the intracellular domain of EphA9 in bacterial cells showed that this domain had TK enzymatic activity. The EphA9 species produced in Cos-1 cells transfected with an expression vector were tyrosine-phosphorylated. These data suggest that EphA9 plays its biological role(s) in various organs of chickens as an active TK.