Physcion, a naturally occurring anthraquinone derivative, induces apoptosis and autophagy in human nasopharyngeal carcinoma.

AIM: Physcion is a major bioactive ingredient in the traditional Chinese medicine Radix et Rhizoma Rhei, which has an anthraquinone chemical structure and exhibits a variety of pharmacological activities including laxative, hepatoprotective, anti-inflammatory, anti-microbial and anti-proliferative effects. In this study we investigated the effect of physcion on human nasopharyngeal carcinoma in vitro and in vivo, as well as the mechanisms underlying the anti-tumor action. METHODS: The nasopharyngeal carcinoma cell line CNE2 was treated with physcion, and cell viability was detected using MTT and colony formation assays. Flow cytometry was used to assess the cell cycle arrest, mitochondrial membrane potential loss, apoptosis, autophagy and intracellular ROS generation. Apoptotic cell death was also confirmed by a TUNEL assay. The expression of target or marker molecules was determined using Western blotting. The activity of caspase-3, 8, and 9 was detected with an ELISA kit. A xenograft murine model was used to evaluate the in vivo anti-tumor action of physcion, the mice were administered physcion (10, 20 mg·kg-1·d-1, ip) for 30 d. RESULTS: Treatment with physcion (5, 10, and 20 µmol/L) dose-dependently suppressed the cell viability and colony formation in CNE2 cells. Physcion (10 and 20 µmol/L) dose-dependently blocked cell cycle progression at G1 phase and induced both caspase-dependent apoptosis and autophagy in CNE2 cells. Furthermore, physcion treatment induced excessive ROS generation in CNE2 cells, and subsequently disrupted the miR-27a/ZBTB10 axis, resulting in repression of the transcription factor Sp1 that was involved in physcion-induced apoptosis and autophagy. Moreover, physcion-induced autophagy acted as a pro-apoptotic factor, and possibly contributed to physcion-induced apoptosis. In the xenograft murine model, administration of physcion dose-dependently suppressed the tumor growth without affecting the body weight. Furthermore, the anti-tumor effects of physcion were correlated with downregulation of Sp1 and suppression of miR-27a in the tumor tissues. CONCLUSION: Physcion induces apoptosis and autophagy in human nasopharyngeal carcinoma by targeting Sp1, which was mediated by ROS/miR-27a/ZBTB10 signaling. The results suggest that physcion is a promising candidate for the treatment of human nasopharyngeal carcinoma.

Accurate modeling of high order spatial dispersion of wire medium.

The wire medium consisting of an array of parallel thin metallic wires was previously studied by using an effective medium with spatial dispersion. In this paper, the validity of conventional effective model was examined analytically and numerically by studying a canonical structure of the wire medium. It is noted that the conventional model fails for high transversal spatial harmonics, which consequently results in discrepancy in the scattering between the effective model and the physical structure. In this study, we propose a new effective model to include higher order spatial dispersions: instead of the second-order expansion, the proposed dispersion equation is based on the fourth-order expansion of the dispersion equation of the photonic states. Compared with the 3D full-wave simulation results of the wire medium, the proposed model has demonstrated significant improvement in numerical accuracy in characterizing the EM behavior in this type of metamaterials.

[A preliminary study of application of the antibacterial solution containing silver ion to the surface of soft lining material].

We tried to find the effects of the application of the antibacterial solution containing silver ions on the surface of the denture soft lining material. We selected the right concentration of the silver-containing solution and coated a soft lining material with the solution so that the soft lining material could be antibacterial. The antibacterial solution containing silver ions was prepared by sol-gel method. MIC of C. a and S. a were tested by broth dilution test. The surface property and thickness were tested after coated. The in vitro antibacterial ratio against C. a and S. a were demonstrated by the method of plate-counting. A film was formed after coating, while the adequacy was not changed. Antibacterial ratio of 0.64 mg/ml group against C. a was 90.82%, and that against S. a was 94.96% in 24 hours, respectively. It was found that the antibacterial property of the soft lining material can be acquired by coating this antibacterial solution with silver ion, without changing the adequacy.

[Research on different soft liner/base resin thickness ratios and fracture behavior of denture base].

Six groups of soft liner/base resin were made into standard test samples of 60.0 mm x 25.0 mm x 3.0 mm, with different soft lining materials/base resin ratios of 0: 3.0, 0.5: 2.5, 1.0: 2.0, 1.5: 1.5, 2.0: 1.0, 2.5: 0.5. The yield strength and resilience of each group were tested by universal testing machine. We found that when the thickness of soft liner increased, the yield strength of samples was reducing, whereas the resilience was enhancing. The change of yield strength and resilience became stabilized between the ratio of 1.5: 1.5 to 2.03: 1.0. We concluded that, under this testing condition, the thickness of soft liner should not exceed 2.0 mm, and we suggested that the ratio of soft liner/base resin should be controlled within the scope of 1/1 to 2/1 according to the whole base thickness.