Proposed model for the molecular mechanisms underlying TRAIL and DTCD-induced apoptotic pathways.

<p>Proposed model for the molecular mechanisms underlying TRAIL and DTCD-induced apoptotic pathways.</p

DTCD increases DR5 but not DR4 levels in ovarian cancer cell lines.

<p>(A) DTCD-induced DR5 upregulation in A2780 cells. Cells were treated with 10 µM DTCD for the indicated time or treated with indicated amount of DTCD for 24 h and then subjected to Western blot analysis. (B) Effects of DTCD on the surface expression levels of DR5. Cells were incubated with or without 10 µM DTCD for 24 h, then subjected to flow cytometry analysis. (C) DTCD-induced DR5 upregulation in other types of ovarian cancer cells. (D) Effect of DR5 siRNA on DTCD/TRAIL-induced cell death. A2780 cells were transfected with control siRNA or DR5 siRNA. 24 h after the transfection, cells were treated with 10 µM DTCD and 200 ng/mL TRAIL for another 24 h. Cellular viability was determined by MTT assay (<i>left</i>). The levels of DR5 were analyzed by Western Blotting (<i>right</i>). *, <i>P</i><0.05 versus vehicle control.</p

DTCD synergizes with TRAIL in activation of ASK1/ERK pathway.

<p>(A) Cells were treated with DTCD (10 µM) at indicated time points and the expression of ASK1 and p-ASK1 was determined by immunoblotting. For <i>in vitro</i> kinase activity assay, the ASK1 in the lysates was immunoprecipitated (IP) with the anti-ASK1 antibody and then incubated with MKK4 in the presence of [γ-³²P] ATP, and MKK4 phosphorylation was detected via autoradiogram. (B) Suppression of ASK1 expression by RNA interference inhibits DTCD and/or TRAIL-induced apoptosis upon ERK activation. A2780 cells were transfected with ASK1 siRNA and treated with DTCD in the presence or absence of TRAIL. The levels of p-ASK1, ASK1, p-ERK, ERK, Sp1 and DR5 were analyzed by Western Blotting. Cell apoptosis were assayed by AnnexinV/PI staining (C). (D) Oxidation of Trx will bring on dissociation of the complex Trx-1-ASK1 and activation of MAPK system. A2780 cells were treated with DTCD for 1 h. Cell protein lysates were treated with or without DTT (1 mmol/L) for 30 min and then subjected to immunoprecipitation (IP) using an anti-Trx-1 antibody and the precipitates were immunoblotted for ASK1. (E) The level of Trx-1 was detected by Western blot in whole-cell lysates from A2780 cells treated with DTCD for 1 h in the absence or presence of TRAIL (200 ng/mL). Cell lysates were processed to identify Trx-1 redox forms denoted as follows: <i>red</i>, reduced form; <i>ox</i>, oxidized form, the topmost <i>ox</i> band is the one most oxidized.</p

DTCD mediates transcription of DR5 through Sp1 activation.

<p>(A) DTCD treatment increases the DR5 mRNA levels. Real-time PCR was used to quantify the DR5 mRNA levels following 24 h of DTCD treatment. (B) Effects of DTCD on DR5 promoter activity. pDR5/−605 plasmid was transfected into A2780 cells, which were then treated with DTCD (10 µM) for the indicated time points or indicated amounts of DTCD, lysed and assayed for luciferase activity. (C) DTCD activates Sp1 translocation to the nucleus. (D) <i>In vivo</i> binding of Sp1 on DR5 promoter regions by DTCD. ChIP assay was done using antibodies against Sp1 in both cells. Negative controls were done using antibody against rabbit IgG.</p

DTCD sensitizes human ovarian cancer cells to TRAIL-induced cytotoxicity <b><i>in vitro</i></b><b>.</b>

<p>(A) The structural formula of DTCD. (B) Cytotoxic effects of TRAIL or DTCD on human ovarian carcinoma cells. Cells were treated with different concentrations of TRAIL (0–500 ng/mL, <i>left</i>) or DTCD (0–10 µM, <i>right</i>) for 24 h. Then cell viability was determined by MTT assay. *, <i>P</i><0.05, *, <i>P</i><0.01 versus vehicle control. (C) DTCD sensitize resistant ovarian cancer cells, but not HOSE cells to TRAIL induced cytotoxicity. Ovarian cancer cells and HEMC cells were treated simultaneously with DTCD (10 µM) and/or TRAIL (200 ng/mL) for 24 h. (D) Synergistic induction of cell death by DTCD and TRAIL. For combination experiments, five doses of DTCD and TRAIL were used from serial dilutions covering the IC₅₀ (fractional affected 0.5) values. The combination index (CI) analysis was conducted according to the median-effect plot analysis of Chou and Talalay. CI <1, CI = 1, and CI >1 represent synergism, additivity, and antagonism of the two agents, respectively. (E) Effects of combined treatment with DTCD and TRAIL on cell apoptosis. Cells were treated with DTCD (10 µM) and/or TRAIL (200 ng/mL) for 24 h after 30 min pretreatment with (+)/without (−) z-VAD-fmk (25 µM), then assayed by AnnexinV/PI staining. (F) Representative images of DNA fragmentation and nuclear condensation in response to DTCD and/or TRAIL treatment as detected by TUNEL and DAPI staining assay (magnification, 200×).</p

DTCD affects the levels of MAPK phosphorylation.

<p>A2780 cells were incubated with 10 µM of DTCD for indicated times (A) or with indicated amounts of DTCD+TRAIL for 1 h (B) and the levels of -ERK, -JNK, - p38 and their phosphorylated forms were determined by western blotting. (C) MAPKs are involved in DTCD-mediated upregulation of Sp1 DNA binding activity. A2780 cells were stimulated with 10 µM DTCD for 24 h after pretreatment with 20 µmol/L PD98059, 20 µmol/L SP600125, and 10 µmol/L SB203580 for 1 h. Then, Sp1 DNA binding activity and nuclear translocation were analyzed by EMSA (<i>left</i>) and Western blotting (<i>right</i>), respectively. (D) Effects of PD98059 on DR5 promoter activity and expression assay. PD98059 inhibits DR5 luciferase activity induced by DTCD. pDR5/605 plasmid was transfected into A2780 cells, which were then pretreated with 20 µmol/L PD98059 for 1 h and further treated with 10 µM DTCD for 24 h, lysed and assayed for luciferase activity and Western blot assay, respectively. (E) Effects of PD98059 on the cytotoxicity induced by DTCD and TRAIL.A2780 cells were treated with DTCD (10 µM) and TRAIL (200 ng/mL) in the presence of indicated amount of PD98059 for 24 h. Cell viability was determined by MTT assay. (F) Cells were transfected with ERK1 siRNA, ERK 2 siRNA or control siRNA, respectively. 24 h after the transfection, cells were treated with 10 µM DTCD for another 24 h, and cell extracts were subjected to Western blotting. (G) Cells were transfected with JNK1/2 siRNA or p38 siRNA, then treated with 10 µM DTCD for 24 h. Western blotting was then used to analyze the extracts for JNK, and p38 MAPK expression.</p

<i>In vivo</i> efficacy of TRAIL in combination with DTCD.

<p>(A) The tumor growth inhibitory effect of DTCD and TRAIL on A2780 human xenograft models. The relative tumor volume (RTV) on day n was calculated using RTV = TVn/TV₀, where TVn is the TV on day n and TV0 is the TV on day 0. (B) Therapeutic effect of treatment was expressed in terms of T/C. The calculation formula is T/C (%) = mean RTV of the treated group/mean RTV of the control group×100%.</p

Black Anatase Titania with Ultrafast Sodium-Storage Performances Stimulated by Oxygen Vacancies

Nanostructured black anatase titania with oxygen vacancies (OVs) is efficiently obtained and employed as an anode in sodium-ion batteries (SIBs) for the first time. The incorporation of OVs into TiO₂ is demonstrated to render considerably enhanced-rate performances, higher initial capacities, and an accelerated electrochemical activation process during cycling, derived from the boosted intrinsic electric conductivity and improved kinetics of Na uptake. Bestowed with the integrated merits of OVs and shortened Na ion diffusion length in the nanostructure, black titania delivers a reversible specific capacity of 207.6 mAh g^–1 at 0.2 C, retains 99.1% over 500 cycles at 1 C stably, and still maintains 91.2 mAh g^–1 even at the high rate of 20 C. Density functional theory (DFT) calculations suggest that the lower sodiation energy barrier of anatase with OVs enables a more favorable Na intercalation into black anatase. Thus, it is of great significance to introduce OVs into TiO₂ to stimulate ultrafast and durable sodium-storage properties, which also offers a potential strategy to project more superior electrodes, utilizing internal defects