Effects of Selenium Species on the Belousov-Zhabotinsky Reaction.

The effects of selenium species on the Belousov-Zhabotinsky (B-Z) reaction were investigated by adding them to the system before and during oscillation. When selenium species were added into the system before oscillation, sodium selenite prolonged the induction period, whose effect was strong as sodium selenite could consume malonic acid to prohibit the accumulation of bromomalonic acid. For selenomethionine and selenocystine, their effects were derived from their reaction with •CH2COOH and •Br2- producing a radical cation of selenoamino acids, which prohibited the accumulation of bromomalonic acid. Here, the selenium atoms in selenoamino acids, as reactive centers, took part in the redox reaction. As a result, the induction period was prolonged. However, as a diselenide, selenocystine can reduce bromate in acidic medium, which led to shortening of the induction period. Therefore, the effect of selenocystine on the induction period was the result of two opposite effects. Nanoselenium shortened the induction period in a certain concentration range because bromate was directly reduced by nanoselenium and the accumulation of bromomalonic acid was promoted. Furthermore, the dose perturbation effect was investigated by the injection of nanoselenium during oscillation. It was found that the amplitude was increased or decreased in a dose-dependent fashion when nanoselenium was injected at peak or trough of the time-dependent redox potential curve.

Anticancer and Antiangiogenic Iron(II) Complexes That Target Thioredoxin Reductase to Trigger Cancer Cell Apoptosis.

Thioredoxin reductase (TrxR) is a selenoenzyme that could regulate intracellular oxidative balance and found to be overexpressed in many human tumor cells. Due to its important role in cancer progression, TrxR is becoming an attractive target in chemotherapeutic drug design. In this study, a new class of Fe(II) complexes with phenanthroline derivatives as ligands were synthesized and characterized. The mechanism of cell death induced by complex 3 revealed that the growth of cancer cells was suppressed by apoptosis and specifically inhibited the activities of TrxR. Furthermore, complex 3 exhibited brilliant antiangiogenic activity against HUVEC cells and inhibited cell migration and invasion. In addition, results of hematological analysis and H&E staining demonstrated that complex 3 has negligible toxicity on function of the major organs of mice. Taken together, this study provides a strategy for drug design to exploit Fe-based phenanthroline derivative as a chemotherapeutic agent in cancer treatment.

Data on the characterization and anticancer action of iron(II) polypyridyl complexes.

This data article contains complementary figures and results related to the research article entitled, "Cellular localization of iron(II) polypyridyl complexes determines their anticancer action mechanisms" [1] (Chen et al., 2015). The characterization of Fe(II) complexes by ESI-MS, (1)H NMR, (13)C NMR spectroscopy, FT-IR spectra, UV-vis spectra was provided. Also,the data for the stability of Fe(II) complexes 1-5 in DMSO/Milli-Q water/ culture medium (without serum or phenol red) at 37 °C at different periods of time by UV-vis spectra and (1)H NMR was showed. At the same time, the anticancer efficacy, cellular distribution and ROS generation in MCF-7 cells of complexes are reported. In addition, we also show the cellular localization of complex 4, the relative fluorescence intensity of complex 1 and complex 3 pretreated with anti-TfR (2 µg/mL) in MCF-7 cells using flow cytometry. The compilation of this data provides an invaluable resource for the wider research community and the interpretation of these data could be found in the research article noted above.

X-ray-responsive selenium nanoparticles for enhanced cancer chemo-radiotherapy.

Resistance of cancer to radiotherapy and/or chemotherapy is one of the important reasons of clinical treatment failure and recurrence. Chemoradiation is an optional method to over-coming of radioresistance and chemoresistance. Selenium nanoparticles (SeNPs) with special chemical and physical properties, has been identified as a novel nanocarrier and therapy agent with broad-spectrum anticancer activities due to generate ROS in cells. Herein, X-ray responsive selenium nanoparticles were facilely fabricated by using PEG as surface decorator and template. This nanosystem (PEG-SeNPs) demonstrated X-ray responsive property that was attributed to its amorphous characteristic. Interestingly, the nanosystem demonstrated significant radiosensitization effects with X-ray. Specifically, co-treatment of cancer cells with PEG-SeNPs and X-ray significantly and synergistically enhanced the cells growth inhibition through induction of cell apoptosis, as evidenced by DNA fragmentation and activation of caspase-3. In the cell model, we found that internalized nanoparticles could degrade upon X-ray exposure, which further confirm the X-ray responsive property of the nanoparticles. Moreover, the nanosystem could significantly induced intracellular ROS generation in a time-dependent manner, which peaked at about 40min and gradually decreased thereafter. As a results, ROS overproduction led to mitochondria fragmentation and the cell apoptosis. Taken together, this study provides a novel strategy for rational design and facile synthesis of chemo-radio therapeutic radiosensitization nanomaterials.

Cellular localization of iron(II) polypyridyl complexes determines their anticancer action mechanisms.

Elucidation of relationship among cellular uptake, localization and biological activities of metal complexes could make great breakthrough in the understanding of their action mechanisms and provide useful information for rational design of metal-based anticancer drugs. Iron(II) complexes have emerged as potential anticancer drug candidates with application potential in cancer imaging and therapy. Herein, a series of iron(II) polypyridyl complexes with different lipophilicity were rationally designed, synthesized and identified as potent anticancer agents. The relationship between the cellular localization and molecular action mechanisms of the complexes was also elucidated. The results showed that, the increase in planarity of the Fe(II) polypyridyl complexes enhanced their lipophilicity and cellular uptake, leading to improved anticancer efficacy. The hydrophilic Fe(II) complex entered cancer cells through transferring receptor (TfR)-mediated endocytosis, and translocated to cell nucleus, where they induced S phase cell cycle arrest through triggering DNA damage-mediated p53 pathway. Interestingly, the hydrophobic Fe(II) complexes displayed higher anticancer efficacy than the hydrophilic ones, but shared the same uptake pathway (TfR-mediated endocytosis) in cancer cells. They accumulated and localized in cell cytoplasm, and induced G0/G1 cells cycle arrest through regulation of AKT pathway and activation of downstream effector proteins. These results support that the cellular localization of Fe(II) complexes regulated by their lipophilicity could affect the anticancer efficacy and action mechanisms. Taken together, this study may enhance our understanding on the rational design of the next-generation anticancer metal complexes.

Mixed-ligand ruthenium polypyridyl complexes as apoptosis inducers in cancer cells, the cellular translocation and the important role of ROS-mediated signaling.

Ruthenium (Ru) polypyridyl complexes have emerged as leading players among the potential metal-based candidates for cancer treatment. However, the roles of cellular translocation in their action mechanisms remain elusive. Herein we present the synthesis and characterization of a series of ruthenium (Ru) complexes containing phenanthroline derivatives with varying lipophilicities, and examine their mechanism of anticancer action. Results showed that increasing the lipophilicity of complexes can enhance the rates of cellular uptake. The in vitro anticancer efficacy of these complexes depended on the levels of ROS overproduction, rather than on cellular Ru uptake levels. The introduction of a phenolic group on the ligand effectively enhanced their intracellular ROS generation and anticancer activities. In particular, complex 4, with an ortho-phenolic group on the ligand, exhibited better selectivity between cancer and normal cells in comparison with cisplatin. Notably, complex 4 entered the cancer cells partially through transferrin receptor-mediated endocytosis, and then it translocated from lysosomes to the mitochondria, where it activated mitochondrial dysfunction by regulation of Bcl-2 family proteins, thus leading to intracellular ROS overproduction. Excess ROS amplified apoptotic signals by activating many downstream pathways such as p53 and MAPK pathways to promote cell apoptosis. Overall, this study provides a drug design strategy for discovery of Ru-based apoptosis inducers, and elucidates the intracellular translocation of these complexes.

Ruthenium polypyridyl complexes as inducer of ROS-mediated apoptosis in cancer cells by targeting thioredoxin reductase.

TrxR is an NADPH-dependent selenoenzyme upregulated in a number of cancers. It plays a pivotal role in cancer progression and represents an increasingly attractive target for anticancer drugs. The limitations of cisplatin in cancer treatment have motivated the extensive investigation to other metal complexes, especially ruthenium (Ru) complexes. In this study, we present the in vitro biological evaluation of four Ru(II) polypridyl complexes with diimine ligands, namely, [Ru(bpy)3](2+) (1), [Ru(phen)3](2+) (2), [Ru(ip)3](2+) (3), [Ru(pip)3](2+) (4) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, ip = imidazole[4,5-f][1,10]phenanthroline, pip = 2-phenylimidazo[4,5-f][1,10]phenanthroline), and demonstrate that they exhibit antiproliferative activities against A375 human melanoma cells through inhibition of TrxR. As the planarity of the structure increases, their TrxR-inhibitory effects and in vitro anticancer activities were enhanced. Among them, complex 4 exhibited higher antiproliferative activity than cisplatin, and the TrxR-inhibitory potency of 4 was more effective than auranofin, a positive TrxR inhibitor. Complex 4 suppressed the cancer cell growth through induction of apoptosis as evidenced by accumulation of sub-G1 cell population, DNA fragmentation and nuclear condensation. Moreover, complex 4 was able to localize in mitochondria and therein induced ROS-dependent apoptosis by inhibition of TrxR activity. Activation of MAPKs, AKT, DNA damage-mediated p53 phosphorylation and inhibition of VEGFR signaling were also triggered in cells exposed to complex 4. On the basis of this evidence, we suggest that Ru polypyridyl complexes could be developed as TrxR-targeted agents that demonstrate application potentials for treatment of cancers.

Dinuclear zinc(II) complexes containing (benzimidazol-2-yl)benzene that overcome drug resistance in hepatocellular carcinoma cells through induction of mitochondria fragmentation.

Herein we demonstrated that dinuclear zinc complexes could overcome drug resistance in R-HepG2 drug resistance hepatocellular carcinoma cells through induction of mitochondria-mediated apoptosis or by triggering mitochondria fragmentation, depletion of the membrane potential and intracellular ATP levels.

[Observation on hybrid bioartificial liver support systems in treating chronic severe hepatitis: a study of 60 cases].

OBJECTIVE: To study the clinical efficacy of three kinds of hybrid bioartificial liver support systems (HBLSS) in treating chronic severe hepatitis. METHODS: A bioartificial liver support system (BAL), comprising porcine hepatocytes and fiber tube style bioreactor, was constructed. Then three kinds of HBLSS were constructed: Molecular absorbent recirculating system (MARS) plus BAL; slow plasma exchange (SPE) plus continuous hemodiafiltration (CHDF) and BAL; and SPE plus hemoperfusion (HP) and BAL. One hundred-twenty patients in middle or late stages of chronic severe hepatitis were enrolled in this study. They were randomly divided into 6 groups: H1 group was treated with BAL+MARS, H2 with BAL+SPE+CHDF and H3 with BAL+SPE+HP (as treatment groups); C1 group was treated with MARS, C2 with SPE+CHDF and C3 with SPE+HP (as control groups). The changes in the clinical symptoms, in the hepatic encephalopathy stages, and in the serum total bilirubin (TBIL), the serum albumin (ALB), the prothrombin activities (PTA), endotoxin, ammonia, creatinine and a-fetal protein (AFP) were all observed before the treatment, right after it and 72 hours later. The improving and curing rates and the rates of side effect occurrences in each group were observed. RESULTS: In all 6 groups, the patients' clinical symptoms ameliorated; their TBIL, endotoxin and ammonia levels decreased (P<0.05), and their PTA and AFP levels lowered significantly (P<0.05). But in the H1, H2 and H3 groups they were more distinctive than in the control groups. In H1 and H2 groups creatinine and ammonia levels were decreased more significantly than in the H3 group (P<0.05). The improving and curing rates of each group were 65 % (13/20), 60% (12/20), 45% (9/20), 45% (9/20), 40% (8/20) and 20% (4/20) respectively. No serious side effects were observed during the treatment. CONCLUSION: In treating middle and late stage chronic severe hepatitis, the measures used in H1, H2 and H3 are better than those in C1, C2 and C3. Furthermore, H1 and H2 treatments can ameliorate hepatic and renal functions, prevent the development of multiple organ dysfunction syndrome, and are better than those used in H3.

[Therapeutic application of molecular adsorbent recirculation system in the treatment of multiple organ dysfunction syndrome patients].

OBJECTIVE: To assess the effectiveness of molecular adsorbent recirculation system (MARS) to remove nitric oxide(NO) and cytokines in multiple organ dysfunction syndrome(MODS) in patients with severe liver failure. METHODS: Single MARS treatment were performed for 198 times with duration ranging from 6 to 24 hours on 61 MODS patients (42M/19F). The efficacy was evaluated by sequential organ failure assessment, biochemical parameters and the levels of pro-inflammatory cytokines. RESULTS: The MARS therapy resulted in a significant removal of NO and certain cytokines such as tumor necrosis factor-alpha(TNF-alpha), interleukin-2(IL-2), IL-6, IL-8, and lipopolysaccharide-binding protein(LBP), together with marked reduction of other non-water soluble albumin bound toxins and water soluble toxins. These were associated with an improvement of the patients' clinical conditions, including deranged hemodynamics, respiratory function, cardiovascular and renal functions, hepatic encephalopathy, thus resulting in a marked decrease of sequential organ failure assessment(SOFA) score and improved outcome. Twenty-five patients were able to be discharged from the hospital, and successful liver transplantation could be performed in 6 patients. The overall survival rate of 61 patients was 41.0%. CONCLUSION: MARS could be used for the treatment of MODS patients associated with elevated levels of NO and cytokines with satisfactory results.