Strategies for the development of selenium-based anticancer drugs

A Photoinducible DNA Cross-Linking Agent with Potent Cytotoxicity and Selectivity Toward Triple-Negative Breast Cancer Cell Line

DNA interstrand cross-links (ICLs) are the sources of the cytotoxicity of many anticancer agents. Selenium compounds showed great potential as anticancer drugs. In this work, we synthesized a binaphthalene analog 1 containing phenyl selenide (-SePh) as the leaving group and investigated its photochemical reactivity toward DNA as well as its cytotoxicity and selectivity. DNA ICLs were not observed with binaphthalene phenyl selenide 1 without UV irradiation, while ∼15% DNA ICL products were detected with UV irradiation, indicating a photoresponsive property of 1. The trapping reactions with TEMPO and MeONH2, respectively, suggested that free radicals and carbocations are involved in the DNA cross-linking process induced by the photoirradiation of 1. The photochemical reactivity of 1 toward DNA was sequence-dependent. DNA interstrand cross-linking occurred mainly at dG/dC base pairs, while monoalkylations occurred at dGs and dAs. Additionally, we have demonstrated that 1 alone without UV irradiation did not inhibit cancer cell growth even with a concentration of 100 μM, while the cytotoxicity of 1 toward cancer cells was significantly enhanced upon 350 nm irradiation with an IC50 of 1.7 μM. No cytotoxicity was observed toward normal epithelial MCF 10A cells, regardless of UV exposure, in the presence or absence of 1. The alkaline comet assay suggested that the photoinduced cytotoxicity of 1 is correlated to cellular DNA damage. Normal cells showed higher levels of GSH than cancer cells and exhibited efficient DNA repair mechanisms, which can both prevent and repair potential DNA damage induced by 1, contributing to the selective cytotoxicity of the prodrug toward triple-negative breast cancer cells.

Synthesis, cytotoxicity, antioxidant activity and molecular modeling of new NSAIDs-EBS derivatives

Two series of NSAIDs-EBS derivatives (5a-j and 9a-i) based on the hybridization of nonsteroidal anti-inflammatory drugs (NSAIDs) skeleton and Ebselen moiety were synthesized. Their cytotoxicity was evaluated against five types of human cancer cell lines, BGC-823 (human gastric cancer cell line), SW480 (human colon adenocarcinoma cells), MCF-7 (human breast adenocarcinoma cells), HeLa (human cervical cancer cells), A549 (human lung carcinoma cells). Moreover, the most active compound 5j showed IC50 values below 3 μM in all cancer cell lines and with remarkable anticancer activity against MCF-7 (1.5 μM) and HeLa (1.7 μM). The redox properties of the NSAIDs-EBS derivatives prepared herein were conducted by 2, 2-didiphenyl-1-picrylhydrazyl (DPPH), bleomycin dependent DNA damage and glutathione peroxidase (GPx)-like assays. Finally, TrxR1 inhibition activity assay and molecular docking study revealed NSAIDs-EBS derivatives could serve as potential TrxR1 inhibitor.

The association between serum selenium levels and pathological features of papillary thyroid cancer in 284 patients

Objective

The relationship between serum selenium levels and papillary thyroid cancer (PTC), especially the pathological features, still remains controversial. We conducted this study to investigate the relationship between serum selenium levels and PTC in a Chinese population.

Methods

Cross-sectional data of 284 patients with PTC were collected from the First Affiliated Hospital of Shandong First Medical University. The general clinical characteristics, serum selenium levels, and tumor pathological features were described in PTC. The association between serum selenium levels and pathological features in PTC was analyzed using SPSS 26.0 statistical software.

Results

Our results showed that the median serum selenium level was 79.15 μg/L (IQR: 71.00 - 86.98 μg/L) in PTC patients. Serum selenium levels were lower in females than males (p = 0.035). Serum selenium levels were negatively correlated with the number of lymph node metastases (p = 0.048). High serum selenium (OR = 0.397, 95%CI: 0.217 - 0.725) and diastolic blood pressure (OR = 1.028, 95%CI: 1.005 - 1.051) were related factors for the incidence of bilateral tumors. High serum selenium (OR = 0.320, 95%CI: 0.166 - 0.617) and diastolic blood pressure (OR = 1.066, 95%CI: 1.031 - 1.103) were related factors for tumor multifocal incidence.

Conclusions

The serum selenium levels of PTC patients in females were lower than males. High serum selenium levels might be a protective factor in PTC patients. Further research is necessary to better understand the influence of selenium on PTC progression.

Age-dependent assessment of selenium nanoparticles: biodistribution and toxicity study in young and adult rats

Aim: To study the biodistribution and toxicology of selenium nanoparticles (SeNPs) versus their bulk counterpart in young and adult male rats in a 28-day study. Methods: SeNPs were synthesized and conjugated with indocyanine green to assess comparative biodistribution by in vivo imaging and further characterized by transmission electron microscopy, Fourier transform infrared, scanning electron microscopy/energy dispersive x-ray spectroscopy, UV and ζ-analysis. The toxicity of bulk selenium was evaluated relative to its nano form by hematology indices, redox, inflammatory markers and histopathology. Results: Indocyanine green-conjugated nanoparticles showed preferential accumulation in the liver, followed by testis and kidney. The protective effect of SeNPs was more significantly observed in young livers than in adults compared with the bulk counterpart. Conclusion: Age-dependent monitoring and diagnosis of toxicity may need different biomarkers of selenium and may also provide better understanding of SeNPs as therapeutics.

Triple Cross-linked Dynamic Responsive Hydrogel Loaded with Selenium Nanoparticles for Modulating the Inflammatory Microenvironment via PI3K/Akt/NF-κB and MAPK Signaling Pathways

Modulating the inflammatory microenvironment can inhibit the process of inflammatory diseases (IDs). A tri-cross-linked inflammatory microenvironment-responsive hydrogel with ideal mechanical properties achieves triggerable and sustained drug delivery and regulates the inflammatory microenvironment. Here, this study develops an inflammatory microenvironment-responsive hydrogel (OD-PP@SeNPs) composed of phenylboronic acid grafted polylysine (PP), oxidized dextran (OD), and selenium nanoparticles (SeNPs). The introduction of SeNPs as initiators and nano-fillers into the hydrogel results in extra cross-linking of the polymer network through hydrogen bonding. Based on Schiff base bonds, Phenylboronate ester bonds, and hydrogen bonds, a reactive oxygen species (ROS)/pH dual responsive hydrogel with a triple-network is achieved. The hydrogel has injectable, self-healing, adhesion, outstanding flexibility, suitable swelling capacity, optimal biodegradability, excellent stimuli-responsive active substance release performance, and prominent biocompatibility. Most importantly, the hydrogel with ROS scavenging and pH-regulating ability protects cells from oxidative stress and induces macrophages into M2 polarization to reduce inflammatory cytokines through PI3K/AKT/NF-κB and MAPK pathways, exerting anti-inflammatory effects and reshaping the inflammatory microenvironment, thereby effectively treating typical IDs, including S. aureus infected wound and rheumatoid arthritis in rats. In conclusion, this dynamically responsive injectable hydrogel with a triple-network structure provides an effective strategy to treat IDs, holding great promise in clinical application.

Preparation of Selenium-Based Drug-Modified Polymeric Ligand-Functionalised Fe3O4 Nanoparticles as Multimodal Drug Carrier and Magnetic Hyperthermia Inductor

In recent years, much effort has been invested into developing multifunctional drug delivery systems to overcome the drawbacks of conventional carriers. Magnetic nanoparticles are not generally used as carriers but can be functionalised with several different biomolecules and their size can be tailored to present a hyperthermia response, allowing for the design of multifunctional systems which can be active in therapies. In this work, we have designed a drug carrier nanosystem based on Fe₃O₄ nanoparticles with large heating power and 4-amino-2-pentylselenoquinazoline as an attached drug that exhibits oxidative properties and high selectivity against a variety of cancer malignant cells. For this propose, two samples composed of homogeneous Fe₃O₄ nanoparticles (NPs) with different sizes, shapes, and magnetic properties have been synthesised and characterised. The surface modification of the prepared Fe₃O₄ nanoparticles has been developed using copolymers composed of poly(ethylene-alt-maleic anhydride), dodecylamine, polyethylene glycol and the drug 4-amino-2-pentylselenoquinazoline. The obtained nanosystems were properly characterised. Their in vitro efficacy in colon cancer cells and as magnetic hyperthermia inductors was analysed, thereby leaving the door open for their potential application as multimodal agents.

An injectable hydrogel based on Bi2Se3 nanosheets and hyaluronic acid for chemo-photothermal synergistic therapy

To resolve poor accumulation caused by systemic administration, injectable and responsive hydrogels are the prospective drug delivery systems for localized tumor treatment, owning to negligible invasiveness and accurate administration. Herein, an injectable hydrogel, based on dopamine (DA) crosslinked hyaluronic acid and Bi₂Se₃ nanosheets (NSs) loading with doxorubicin (DOX) coated with polydopamine (Bi₂Se₃-DOX@PDA), was developed for synergistic chem-photothermal cancer therapy. The ultrathin functional Bi₂Se₃-DOX@PDA NSs could be responsive to the weak acidic condition and photothermal effect under NIR laser irradiation, achieving controlled release of DOX. Moreover, nanocomposite hydrogel based on hyaluronic acid matrix could be precisely administrated through intratumoral injection since its injectability and self-healing capacity, remaining at injected sites for at least 12 days. Furthermore, the excellent therapeutics effect of Bi₂Se₃-DOX@PDA nanocomposite hydrogel was demonstrated on 4 T1 xenograft tumor with outstanding injectability and negligible systemic side-effect. In short, the construction of Bi₂Se₃-DOX@PDA nanocomposite hydrogel paves a prospective path for local treatment of cancers.

Antiproliferative Effect of Inorganic and Organic Selenium Compounds in Breast Cell Lines

Triple-negative breast cancer (TNBC) is an aggressive, fast-growing tumor that is more likely to spread to distant organs. Among women diagnosed with breast cancer, the prevalence of TNBC is 20%, and treatment is currently limited to chemotherapy. Selenium (Se), an essential micronutrient, has been explored as an antiproliferative agent. Therefore, this study aimed to evaluate the effects of exposure to organic (selenomethionine, ebselen, and diphenyl diselenide) and inorganic (sodium selenate and sodium selenite) Se molecules in different breast cell lines. The compounds were tested at 1, 10, 50, and 100 μM for 48 h in the non-tumor breast cell line (MCF-10A) and TNBC derivatives cell lines (BT-549 and MDA-MB-231). The effects of Se on cell viability, apoptotic and necrotic processes, colony formation, and cell migration were analyzed. Exposure to selenomethionine and selenate did not alter the evaluated parameters. However, selenomethionine had the highest selectivity index (SI). The exposure to the highest doses of selenite, ebselen, and diphenyl diselenide resulted in antiproliferative and antimetastatic effects. Selenite had a high SI to the BT cell line; however, the SI of ebselen and diphenyl diselenide was low in both tumoral cell lines. In conclusion, the Se compounds had different effects on the breast cell lines, and additional tests are needed to reveal the antiproliferative effects of Se compounds.

Using chitosan-stabilized, hyaluronic acid-modified selenium nanoparticles to deliver CD44-targeted PLK1 siRNAs for treating bladder cancer

Aims: Achieving an effective biocompatible system for siRNAs delivery to the tumor site remains a significant challenge. Materials & methods: Selenium nanoparticles (SeNPs) modified by chitosan (CS) and hyaluronic acid (HA) were fabricated for PLK1 siRNAs (siPLK1) delivery to the bladder cancer cells. The HA-CS-SeNP@siPLK1 efficacy was evaluated using in vitro and in vivo models. Results: HA-CS-SeNP@siPLK1 was selectively internalized into T24 cells through clathrin-mediated endocytosis. Treatment with HA-CS-SeNP@siPLK1 successfully silenced the PLK1 gene, inhibited cell proliferation and induced cell cycle arrest in vitro. HA-CS-SeNP@siPLK1 could also inhibit tumor growth in vivo without causing systemic toxicity. Conclusion: Our results suggest that HA-CS-SeNPs may provide a good vehicle for delivering siPLK1 to the bladder tumor site.

Natural Sources of Selenium as Functional Food Products for Chemoprevention

Cancer is one of the leading causes of death worldwide, the incidence of which is increasing annually. Interest has recently grown in the anti-cancer effect of functional foods rich in selenium (Se). Although clinical studies are inconclusive and anti-cancer mechanisms of Se are not fully understood, daily doses of 100-200 µg of Se may inhibit genetic damage and the development of cancer in humans. The anti-cancer effects of this trace element are associated with high doses of Se supplements. The beneficial anti-cancer properties of Se and the difficulty in meeting the daily requirements for this micronutrient in some populations make it worth considering the use of functional foods enriched in Se. This review evaluated studies on the anti-cancer activity of the most used functional products rich in Se on the European market.

Reversal of Multidrug Resistance by Symmetrical Selenoesters in Colon Adenocarcinoma Cells

Recently, selenium containing derivatives have attracted more attention in medicinal chemistry. In the present work, the anticancer activity of symmetrical selenoesters was investigated by studying the reversal of efflux pump-related and apoptosis resistance in sensitive and resistant human colon adenocarcinoma cells expressing the ABCB1 protein. The combined effect of the compounds with doxorubicin was demonstrated with a checkerboard assay. The ABCB1 inhibitory and the apoptosis-inducing effects of the derivatives were measured with flow cytometry. Whole transcriptome sequencing was carried out on Illumina platform upon the treatment of resistant cells with the most potent derivatives. One ketone and three methyl ester selenoesters showed synergistic or weak synergistic interaction with doxorubicin, respectively. Ketone selenoesters were the most potent ABCB1 inhibitors and apoptosis inducers. Nitrile selenoesters could induce moderate early and late apoptotic processes that could be explained by their ABCB1 modulating properties. The transcriptome analysis revealed that symmetrical selenoesters may influence the redox state of the cells and interfere with metastasis formation. It can be assumed that these symmetrical selenocompounds possess toxic, DNA-damaging effects due to the presence of two selenium atoms in the molecule, which may be augmented by the presence of symmetrical groups.

Synthesis of Selenoesters via Aldol Condensation and/or Conjugate Reduction and Their Antiviral Activities

A variety of unsaturated selenoesters (including phenolic ones) were produced in good to high yields and with high E/Z ratios using TiCl₄-promoted aldol condensation between Se-phenyl selenoacetate and their respective aldehydes without aqueous workup. A representative phenolic unsaturated selenoester was applied to acylation of tyrosine methyl ester without protection of the phenolic hydroxy groups to furnish the corresponding amino acid conjugate. The conjugate reduction of the unsaturated selenoesters including phenolic ones and selenocoumarin with HSiEt₃ was catalyzed by B(C₆F₅)₃ to afford the corresponding saturated selenoesters in good to high yields. This method was also applicable to the reduction of a saturated selenoester to the corresponding O-silyl hemiselenoacetal in a high yield. Moreover, most acyclic unsaturated selenoesters were found to show good multiple antiviral activities against HIV-1, HBV, and SARS-CoV-2.

The protective role of nutritional antioxidants against oxidative stress in thyroid disorders

An imbalance between pro-oxidative and antioxidative cellular mechanisms is oxidative stress (OxS) which may be systemic or organ-specific. Although OxS is a consequence of normal body and organ physiology, severely impaired oxidative homeostasis results in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells' function and viability. The thyroid gland is an organ that exhibits both oxidative and antioxidative processes. In terms of OxS severity, the thyroid gland's response could be physiological (i.e. hormone production and secretion) or pathological (i.e. development of diseases, such as goitre, thyroid cancer, or thyroiditis). Protective nutritional antioxidants may benefit defensive antioxidative systems in resolving pro-oxidative dominance and redox imbalance, preventing or delaying chronic thyroid diseases. This review provides information on nutritional antioxidants and their protective roles against impaired redox homeostasis in various thyroid pathologies. We also review novel findings related to the connection between the thyroid gland and gut microbiome and analyze the effects of probiotics with antioxidant properties on thyroid diseases.

Synthesis of selenophene-based chalcone analogs and assessment of their biological activity as anticancer agents

Selenium is an essential micronutrient that is beneficial to human health. Selenium-containing drugs have been developed as antioxidants, anti-inflammatory, and anticancer agents. However, the synthesis of selenium-containing chalcones has not been fully explored. Therefore, we report the synthesis of novel selenophene-based chalcone analogs and reveal their biological activities as anticancer agents. Among the seven synthesized molecules, compounds 6, 8, and 10 exhibited anticancer activity with IC₅₀ values of 19.98 ± 3.38, 38.23 ± 3.30, and 46.95 ± 5.68 μM, respectively, against human colorectal adenocarcinoma (HT-29) cells. Clonogenic assays and Western blot analysis tests further confirmed that compound 6 effectively induced apoptosis in HT-29 cells through mitochondrial- and caspase-3-dependent pathways.

Anti-inflammatory and Immunomodulatory Potency of Selenium-Enriched Probiotic Mutants in Mice with Induced Ulcerative Colitis

Selenium-enriched Lactobacillus plantarum and Bifidobacterium longum mutants were used as a protector against Piroxicam-induced ulcerative colitis (UC). In this study, 32 BALB/c male mice were distributed to four groups: the control group, the Piroxicam group which was given 0.8 mg Piroxicam, SP and SB groups which were given 0.8 mg Piroxicam, and plus Lactobacillus plantarum and Bifidobacterium longum selenium-enriched mutants, respectively. Bodyweight; serum content of IgG, IgM, TNF-α, IL-2, IL-6, and IL-10; CBC; myeloperoxidase enzyme activity; histopathological examination of colon and spleen; and expression of TNF-α, IL-2, IL-6, and IL-10 genes in colon and spleen with qRT-PCR were determined. Bodyweight was found to reduce in the Piroxicam group and then recovery in the SB group. Serum content of IgG, IL-2, and IL-10 reduced in the Piroxicam group, whereas IgG, TNF-α, and IL-6 increased in the Piroxicam group in comparison to the other groups. Myeloperoxidase activity witnessed a significant increase in the Piroxicam group compared with the other groups. No significant differences were observed between all groups in measurements of red cells, hemoglobin, neutrophil, monocyte, eosinophil, and basophil in blood. Meanwhile, the white blood cells and platelets recorded the highest and lowest value, respectively, in the Piroxicam group. The colon of the Piroxicam group showed a noticeably massive infiltration of inflammatory cells in the lamina propria. These inflammations were mildly reduced in the SP group, while the reduction in the SB group was significant. In the Piroxicam group, splenic parenchyma saw an increase in the number of melanomacrophages, while hypertrophic plasma cells were observed in the SP group. The spleen of the SB group exhibits a nearly normal form. TNF-α and IL-6 genes had significantly upregulated in the colon of the Piroxicam group compared to the control group, while they were significantly downregulated in the SB group. In contrast, IL-2 and IL-10 genes had upregulated in the colon of the SB group compared to the control groups, while they had downregulated in the Piroxicam group. The expression of these genes had not recorded significant differences between all groups in the spleen. Therefore, this study recommends Bifidobacterium longum selenium-enriched mutants as anti-inflammatory and immunomodulatory supplements.

Systemic Essential Metal and Metalloid Levels in Patients with Benign Breast Disease and Breast Cancer

The objective of the present study is evaluation of serum and hair levels of essential metals and metalloids in women with benign breast disease and breast cancer in order to define similar and distinct patterns that may mediate the link between these pathologies. A total of 310 adult women aged 20-80 years old were enrolled in the present study. Of those, 103 patients had benign (fibrocystic) breast disease, 107 patients had breast cancer (stage II), and 100 women were healthy and with absence of breast pathology. Trace metal and metalloid levels in hair and serum were evaluated by inductively coupled argon plasma mass-spectrometry (ICP-MS). The data demonstrate that breast cancer patients were characterized by significantly higher hair Cr and V levels, as well as reduced Cu and Mn content as compared to both benign breast disease patients and controls. In contrast, serum Cu levels in women with breast cancer exceeded those in the controls and benign breast disease cases. Patients with both benign and malignant breast tumors were characterized by lower serum Mn levels as compared to the control values. Serum Cu/Zn and especially Cu/Mn were found to be significantly increased in cancer patients. Significantly reduced hair and serum Se levels were noted only in women with fibrocystic disease. Based on the analysis of two biosamples, it is proposed that malignant breast tumor development is associated with the reduction of systemic Mn and Zn levels, and a concomitant elevation of Cu concentrations.

The role of selenoprotein P in the determining the sensitivity of cervical cancer patients to concurrent chemoradiotherapy: A metabonomics-based analysis

BACKGROUND

The effect of selenoprotein P (SELENOP) levels on the sensitivity of cervical cancer patients to concurrent chemoradiotherapy (CCRT) has not been reported. In this study, the effects of the variations in plasma SELENOP levels on the sensitivity of cervical cancer patients to CCRT were investigated using metabonomics.

METHODS

Two patient groups were evaluated, i.e., the case group: 11 patients with intermediate to advanced primary squamous cervical cancer, who developed resistance against CCRT, and the sensitivity group: 11 patients who did not develop resistance were matched in a 1:1 ratio (controls). Blood samples were collected before and after CCRT, and the plasma SELENOP levels were measured by ELISA. The different metabolites present in the plasma were analyzed by UPLC-MS-MS.

RESULTS

SELENOP levels exhibited a significant reduction in both the resistant and sensitive groups after CCRT (F = 50.705, P < 0.001), and interaction effects between sensitivity and pre-and post-treatment on SELENOP levels were observed (F = 7.414, P = 0.013). Further, a more significant reduction in the SELENOP levels was observed in the CCRT-resistant group (mean reduction, 0.028 µg/mL; P < 0.001) than in the sensitive group (mean reduction, 0.013 µg/mL; P = 0.006). Four metabolic biomarkers, i.e., C18, C19, C20 sphingomyelin, and phosphatidylcholine 20:2/22:6, were shown to be differentially expressed between the resistant and sensitive groups pre-and post-treatment. C20 sphingomyelin levels exhibited a significant correlation with SELENOP levels (r = -0.326, P = 0.031).

CONCLUSION

The levels of plasma SELENOP in the CCRT-resistant group decreased significantly, suggesting that SELENOP might affect the sensitivity by modulating lipid synthesis and metabolism.

Different Effects of Low Selenite and Selenium-Nanoparticle Supplementation on Adipose Tissue Function and Insulin Secretion in Adolescent Male Rats

Adolescence is a period of intense growth and endocrine changes, and obesity and insulin-resistance processes during this period have lately been rising. Selenium (Se) homeostasis is related to lipid metabolism depending on the form and dose of Se. This study tests the actions of low-dose selenite and Se nanoparticles (SeNPs) on white (WAT) and brown adipose tissue (BAT) deposition, insulin secretion, and GPx1, IRS-1 and FOXO3a expression in the WAT of adolescent rats as regards oxidative stress, adipocyte length and adipokine secretion. Four groups of male adolescent rats were treated: control (C), low selenite supplementation (S), low SeNP supplementation (NS) and moderate SeNP supplementation (NSS). Supplementation was received orally through water intake; NS and NSS rats received two- and tenfold more Se than C animals, respectively. SeNPs were obtained by reducing Se tetrachloride in the presence of ascorbic acid. For the first time in vivo, it was demonstrated that low selenite supplementation contributed to increased adipogenesis via the insulin signaling pathway and LCN2 modulation, while low SeNP administration prevented fat depots in WAT via the decrease in insulin signaling and FOXO3a autophagy in WAT, lowering inflammation. These effects were independent of GPx1 expression or activity in WAT. These findings provide data for dietary approaches to prevent obesity and/or anorexia during adolescence. These findings may be relevant to future studies looking at a nutritional approach aimed at pre-venting obesity and/or anorexia in adolescence.

Citric acid-mediated green synthesis of selenium nanoparticles: antioxidant, antimicrobial, and anticoagulant potential applications

Using microwave technique in the presence of citric acid, selenium nanoparticles (SeNPs) were fabricated. The morphological characteristics revealed that the spherical SeNPs with diameters ranging from 10.5 to 20 nm aggregated spherical shapes with sizes ranging from 0.67 to 0.83 mm. Moreover, the antioxidant efficacy was assessed by the DPPH radical scavenging test, which depicted that green-prepared nanoparticle at a 106.3 mg/mL dosage had the maximum scavenging capacity (301.1 ± 11.42 mg/g). Otherwise, with nanoparticle concentrations of 500 mg/ml, in vitro cell viability of SeNPs through human breast cancer MCF-7 cell lines was reduced to 61.2 ± 2.2% after 1 day of exposure. The antibacterial activity was tested against G-negative Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli), G-positive bacteria Bacillus subtilis (B. subtilis), and Staphylococcus aureus (S. aureus), which demonstrated that SeNPs had little activity against S. aureus. Still, it had the highest activity against E. coli, with a zone of inhibition (ZOI) of 25.2 ± 1.5 mm compared to 16.0 ± 0.6 mm for the standard antibiotic. Most notably, biogenic SeNPs have anticoagulant activities using activated partial thromboplastin time (aPTT) assessment. Based on previous findings, SeNPs can be used in medical aid and their cell viability, antioxidant, anticoagulant, and effects on bacteria.

Relationship between the oxidative status and the tumor growth in transplanted triple-negative 4T1 breast tumor mice after oral administration of rhenium(I)-diselenoether

BACKGROUND

Selective inhibitory effects of rhenium(I)-diselenoether (Re-diSe) were observed in cultured breast malignant cells. They were attributed to a decrease in Reactive Oxygen Species (ROS) production. A concomitant decrease in the production of Transforming Growth Factor-beta (TGFβ1), Insulin Growth Factor 1 (IGF1), and Vascular Endothelial Growth Factor A (VEGFA) by the malignant cells was also observed.

AIM

The study aimed to investigate the anti-tumor effects of Re-diSe on mice bearing 4T1 breast tumors, an experimental model of triple-negative breast cancer, and correlate them with several biomarkers.

MATERIAL AND METHODS

4T1 mammary breast cancer cells were orthotopically inoculated into syngenic BALB/c Jack mice. Different doses of Re-diSe (1, 10, and 60 mg/kg) were administered orally for 23 consecutive days to assess the efficacy and toxicity. The oxidative status was evaluated by assaying Advanced Oxidative Protein Products (AOPP), and by the dinitrophenylhydrazone (DNPH) test in plasma of healthy mice, non-treated tumor-bearing mice (controls), treated tumor-bearing mice, and tumors in all tumor-bearing mice. Tumor necrosis factor (TNFα), VEGFA, VEGFB, TGFβ1, Interferon, and selenoprotein P (selenoP) were selected as biomarkers.

RESULTS

Doses of 1 and 10 mg/kg did not affect the tumor weights. There was a significant increase in the tumor weights in mice treated with the maximum dose of 60 mg/kg, concomitantly with a significant decrease in AOPP, TNFα, and TGFβ1 in the tumors. SelenoP concentrations increased in the plasma but not in the tumors.

CONCLUSION

We did not confirm the anti-tumor activity of the Re-diSe compound in this experiment. However, the transplantation of the tumor cells did not induce an expected pro-oxidative status without any increase of the oxidative biomarkers in the plasma of controls compared to healthy mice. This condition could be essential to evaluate the effect of an antioxidant drug. The choice of the experimental model will be primordial to assess the effects of the Re-diSe compound in further studies.

Effect of extracts from eggs of Helix aspersa maxima and Helix aspersa aspersa snails on Caco-2 colon cancer cells

Background

Colorectal cancer is the third most commonly diagnosed cancer. Natural compounds, administered together with conventional chemotherapeutic agent(s) and/or radiotherapy, may be a novel element in the combination therapy of this cancer. Considering the anticancer properties of compounds derived from different tissues of various snail species confirmed earlier, the purpose of the present research was to evaluate the effect of extracts from eggs of Helix aspera maxima and Helix aspersa aspersa snails, and fractions of extracts containing particles of different molecular weights on Caco-2 human epithelial colorectal adenocarcinoma cells.

Methods

The extracts and fractions were analyzed for antioxidant activity, phenols and total carbohydrates using colorimetric methods. Lipid peroxidation products and glutathione in eggs were also examined using these methods. Crude protein and fat in eggs were determined. Molecular weights of egg proteins and glycoproteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Astaxanthin, selected vitamins and amino acids in eggs were measured using liquid chromatography methods, and minerals by emission spectroscopy, mass spectrometry or X-ray fluorescence. The action of extracts on the cell viability was determined by the MTT (methylthiazolyldiphenyl-tetrazolium bromide) test, based on the mitochondrial oxidative activity, after 24 and 72 h of treatment. The influence of fractions on the cell viability was assayed after 24 h. The effect of extracts on the percentage of live and dead cells was evaluated by the trypan blue assay, in which live cells exclude trypan blue, while dead cells take up this dye, after 12, 24, 48 and 72 h of treatment. Their influence on the integrity of cell membranes was determined based on the activity of LDH (lactate dehydrogenase), released from damaged cells, after 24 and 72 h of treatment. Then, the effect of extracts on the content of lipid peroxidation products in cells was examined using colorimetric method, after 24 h of treatment. Their influence on types of cell death was determined by flow cytometry, after this time.

Results

The extracts and their fractions containing molecules <3 kDa decreased the cell viability, after 24 h of treatment. The extracts reduced the percentage of live cells (also after 48 h), increased the degree of cell membrane damage and the amount of lipid peroxidation products, induced apoptosis and reduced necrosis.

Conclusions

Antioxidants, phenols, lipid peroxidation products, anticancer peptides, restriction of methionine, appropriate ratio of essential amino acids to non-essential amino acids, vitamin D3, Ca, Mg, S, Cu, Mn, Zn, Se and other bioactive compounds comprised in the extracts and their additive and synergistic effects may have influenced Caco-2 cells. Natural extracts or the chemical compounds contained in them might be used in the combination therapy of colorectal cancer, which requires further research.

Ni and Fe Catalyzed Cascade Radical Reactions of Oxime Esters with Diselenides

A radical cyclization and ring-opening of oxime esters with diselenides was developed. Both Ni(0) and Fe(II) catalysts could be employed for the selenylation of olefin-containing and cyclic oxime ester derivatives....

Direct selenosulfonylation of unsaturated compounds: a review

In this review, we have discussed recent developments on the direct selenosulfonylation of unsaturated compounds which lead to the formation of two new carbon-sulfur and carbon-selenium bonds in a single operation. The reactions were classified based on the type of starting unsaturated compound and product. Thus, the review is divided into three major sections. The first describes the current literature on selenosulfonylation of alkenes. The second section covers the available literature on selenosulfonylation of alkynes. The third focuses exclusively on selenosulfonylation of allenes.

In this review, we have discussed recent developments on the direct selenosulfonylation of unsaturated compounds which lead to the formation of two new carbon-sulfur and carbon-selenium bonds in a single operation.

NSAIDs: Old Acquaintance in the Pipeline for Cancer Treatment and Prevention─Structural Modulation, Mechanisms of Action, and Bright Future

The limitations of current chemotherapeutic drugs are still a major issue in cancer treatment. Thus, targeted multimodal therapeutic approaches need to be strategically developed to successfully control tumor growth and prevent metastatic burden. Inflammation has long been recognized as a hallmark of cancer and plays a key role in the tumorigenesis and progression of the disease. Several epidemiological, clinical, and preclinical studies have shown that traditional nonsteroidal anti-inflammatory drugs (NSAIDs) exhibit anticancer activities. This Perspective reports the most recent outcomes for the treatment and prevention of different types of cancers for several NSAIDs alone or in combination with current chemotherapeutic drugs. Furthermore, an extensive review of the most promising structural modifications is reported, such as phospho, H₂S, and NO releasing-, selenium-, metal complex-, and natural product-NSAIDs, among others. We also provide a perspective about the new strategies used to obtain more efficient NSAID- or NSAID derivative- formulations for targeted delivery.

Mechanisms of the Cytotoxic Effect of Selenium Nanoparticles in Different Human Cancer Cell Lines

In recent decades, studies on the functional features of Se nanoparticles (SeNP) have gained great popularity due to their high biocompatibility, stability, and pronounced selectivity. A large number of works prove the anticarcinogenic effect of SeNP. In this work, the molecular mechanisms regulating the cytotoxic effects of SeNP, obtained by laser ablation, were studied by the example of four human cancer cell lines: A-172 (glioblastoma), Caco-2, (colorectal adenocarcinoma), DU-145 (prostate carcinoma), MCF-7 (breast adenocarcinoma). It was found that SeNP had different concentration-dependent effects on cancer cells of the four studied human lines. SeNP at concentrations of less than 1 μg/mL had no cytotoxic effect on the studied cancer cells, with the exception of the A-172 cell line, for which 0.5 μg/mL SeNP was the minimum concentration affecting its metabolic activity. It was shown that SeNP concentration-dependently caused cancer cell apoptosis, but not necrosis. In addition, it was found that SeNP enhanced the expression of pro-apoptotic genes in almost all cancer cell lines, with the exception of Caco-2 and activated various pathways of adaptive and pro-apoptotic signaling pathways of UPR. Different effects of SeNP on the expression of ER-resident selenoproteins and selenium-containing glutathione peroxidases and thioredoxin reductases, depending on the cell line, were established. In addition, SeNP triggered Ca²⁺ signals in all investigated cancer cell lines. Different sensitivity of cancer cell lines to SeNP can determine the induction of the process of apoptosis in them through regulation of the Ca²⁺ signaling system, mechanisms of ER stress, and activation of various expression patterns of genes encoding pro-apoptotic proteins.

Therapeutic Potential of Selenium in Glioblastoma

Little progress has been made in the long-term management of malignant brain tumors, leaving patients with glioblastoma, unfortunately, with a fatal prognosis. Glioblastoma remains the most aggressive primary brain cancer in adults. Similar to other cancers, glioblastoma undergoes a cellular metabolic reprogramming to form an oxidative tumor microenvironment, thereby fostering proliferation, angiogenesis and tumor cell survival. Latest investigations revealed that micronutrients, such as selenium, may have positive effects in glioblastoma treatment, providing promising chances regarding the current limitations in surgical treatment and radiochemotherapy outcomes. Selenium is an essential micronutrient with anti-oxidative and anti-cancer properties. There is additional evidence of Se deficiency in patients suffering from brain malignancies, which increases its importance as a therapeutic option for glioblastoma therapy. It is well known that selenium, through selenoproteins, modulates metabolic pathways and regulates redox homeostasis. Therefore, selenium impacts on the interaction in the tumor microenvironment between tumor cells, tumor-associated cells and immune cells. In this review we take a closer look at the current knowledge about the potential of selenium on glioblastoma, by focusing on brain edema, glioma-related angiogenesis, and cells in tumor microenvironment such as glioma-associated microglia/macrophages.

The Activation of Endothelial Cells Relies on a Ferroptosis-Like Mechanism: Novel Perspectives in Management of Angiogenesis and Cancer Therapy

The activation of endothelial cells (ECs) is a crucial step on the road map of tumor angiogenesis and expanding evidence indicates that a pro-oxidant tumor microenvironment, conditioned by cancer metabolic rewiring, is a relevant controller of this process. Herein, we investigated the contribution of oxidative stress-induced ferroptosis to ECs activation. Moreover, we also addressed the anti-angiogenic effect of Propranolol. We observed that a ferroptosis-like mechanism, induced by xCT inhibition with Erastin, at a non-lethal level, promoted features of ECs activation, such as proliferation, migration and vessel-like structures formation, concomitantly with the depletion of reduced glutathione (GSH) and increased levels of oxidative stress and lipid peroxides. Additionally, this ferroptosis-like mechanism promoted vascular endothelial cadherin (VE-cadherin) junctional gaps and potentiated cancer cell adhesion to ECs and transendothelial migration. Propranolol was able to revert Erastin-dependent activation of ECs and increased levels of hydrogen sulfide (H₂S) underlie the mechanism of action of Propranolol. Furthermore, we tested a dual-effect therapy by promoting ECs stability with Propranolol and boosting oxidative stress to induce cancer cell death with a nanoformulation comprising selenium-containing chrysin (SeChry) encapsulated in a fourth generation polyurea dendrimer (SeChry@PURE_G4). Our data showed that novel developments in cancer treatment may rely on multi-targeting strategies focusing on nanoformulations for a safer induction of cancer cell death, taking advantage of tumor vasculature stabilization.

Selenium nanoparticles: Synthesis, in-vitro cytotoxicity, antioxidant activity and interaction studies with ct-DNA and HSA, HHb and Cyt c serum proteins

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Spherical SeNPs with average size 134 nm were synthesized employing Vitamin C.

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The synthesized SeNPs represented great antioxidant and anticancer activity.

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The interaction of SeNPs with ct-DNA, HSA, HHb and Cyt c was investigated.

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Nano-selenium can bind to ct-DNA through partial intercalation binding mode.

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HSA, HHb and Cyt c could keep their biological activity even in the presence of Nano-selenium.

The aim of this study was the synthesis of selenium nanoparticles (SeNPs) employing vitamin C as a biocompatible and low toxic reducing agent. The synthesized selenium nanoparticles were characterized by using UV–vis, FT-IR, SEM-EDX, TEM, DLS, and zeta potential measurements. The results of the DPPH free radical scavenging assay demonstrate that this synthesized nano-selenium has strong potentials to scavenge the free radicals and cytotoxicity against MCF-7 and Raji Burkitt's lymphoma cancer cell lines. The interaction of calf thymus DNA (ct-DNA) with SeNPs indicated that the anticancer activity might be associated with the DNA-binding properties of nano-selenium. Finally, it was found that the synthesized nano-selenium can bind to the most important blood proteins such as human serum albumin (HSA), human hemoglobin (HHb), and Cytochrome c (Cyt c). The results showed that the secondary structure of these proteins remains unchanged, suggesting that the synthesized nano-selenium could be employed as a carrier in the drug delivery system without any cytotoxicity effect.

Transition-metal-free C-S, C-Se, and C-Te Bond Formation from Organoboron Compounds

The present review describes the successful application of organoboron compounds in transition-metal-free C-S, C-Se, and C-Te bond formations. We presented studies regarding these C-Chalcogen bond formations using organoboron reagents, such as boronic acids, boronic esters, borate anions, and several sources of chalcogen atoms/moieties. Moreover, a broad range of transition-metal-free approaches to synthesize sulfides, selenides, and tellurides were described using conventional heating methods, which are sometimes green since they use green solvents, safe reagents, among others. Furthermore, protocols using alternative energy sources, including ultrasound, microwave irradiation, photocatalysis, and electrolytic processes, were also shown to be suitable. These protocols were applied to prepare a broad scope of functionalized chalcogenides with high molecular diversity. These studies and their proposed mechanisms were also reported herein in addition to the reuse of reaction promoters.

A pan-cancer study of selenoprotein genes as promising targets for cancer therapy

BACKGROUND

The most important health benefit of selenium (Se) is in the prevention and control of cancer. Glutathione peroxidases (GPXs) and thioredoxin reductases (TXNRDs) are selenoenzymes that are thought to play a role in oxidative stress. The differential expression of genes of the TXNRD and GPX families is closely related to carcinogenesis and the occurrence of cancer. This study comprehensively analyzed the expression profiles of seven genes in the TXNRD and GPX families, in terms of their correlations with patient survival and immune-cell subtypes, tumor microenvironment, and drug sensitivity.

RESULTS

The expression profiles of genes in the TXNRD and GPX families differ between different types of cancer, and also between and within individual cancer cases. The expression levels of the seven analyzed genes are related to the overall survival of patients. The TXNRD1 and TXNRD3 genes are mainly related to poor prognoses, while other genes are related to good or poor prognoses depending on the type of cancer. All of the genes were found to be correlated to varying degrees with immune-cell subtypes, level of mechanistic cell infiltration, and tumor cell stemness. The TXNRD1, GPX1, and GPX2 genes may exert dual effects in tumor mutagenesis and development, while the TXNRD1, GPX1, GPX2, and GPX3 genes were found to be related to drug sensitivity or the formation of drug resistance.

CONCLUSIONS

The results will greatly help in identifying the association between genes and tumorigenesis, especially in the immune response, tumor microenvironment, and drug resistance, and very important when attempting to identify new therapeutic targets.

Disease Ionomics: Understanding the Role of Ions in Complex Disease

Ionomics is a novel multidisciplinary field that uses advanced techniques to investigate the composition and distribution of all minerals and trace elements in a living organism and their variations under diverse physiological and pathological conditions. It involves both high-throughput elemental profiling technologies and bioinformatic methods, providing opportunities to study the molecular mechanism underlying the metabolism, homeostasis, and cross-talk of these elements. While much effort has been made in exploring the ionomic traits relating to plant physiology and nutrition, the use of ionomics in the research of serious diseases is still in progress. In recent years, a number of ionomic studies have been carried out for a variety of complex diseases, which offer theoretical and practical insights into the etiology, early diagnosis, prognosis, and therapy of them. This review aims to give an overview of recent applications of ionomics in the study of complex diseases and discuss the latest advances and future trends in this area. Overall, disease ionomics may provide substantial information for systematic understanding of the properties of the elements and the dynamic network of elements involved in the onset and development of diseases.

Effects of organic selenium on absorption and bioaccessibility of arsenic in radish under arsenic stress

Arsenic (As) exposure poses a serious threat to human health. The present study investigated the effects of organic Se on As accumulation, migration, and As bioaccessibility in As-stressed radish. The results showed that organic Se can effectively block the accumulation of As in radish, reduce As bioaccessibility, and promote the conversion of As from inorganic to organic form. The total As content decreased with increasing Se application in raw radish roots, the gastric fraction and the gastrointestinal fraction. Compared to the control (CK) group, the As bioaccessibility in the 24Se treatment of the yeast Se and malt Se groups decreased by 26% and 37%, respectively. These findings provide new comprehensive information for the application of organic Se to alleviate the toxicological effects of As and reduce the health risks of As in edible plants. In the future, it is necessary to carry out a deeper study of the interaction between Se and As through advanced analytical methods.

The innovative potential of selenium-containing agents for fighting cancer and viral infections

Selenium-containing compounds have emerged as a potentially promising treatment for viral infections and tumor development and dissemination. Selenium per se is often considered as a toxic element with little or no beneficial effects, but considerable advances have been made in the understanding of the complex biology, chemistry and drug delivery of this element, especially when it is included in bioactive molecules. Here, we summarize and critically discuss recent findings in the field of selenium-based applications for the treatment of cancer and viral infections.

Nutritional supplements in combination with chemotherapy or targeted therapy reduces tumor progression in mice bearing triple-negative breast cancer

The potential anti-cancer properties of selenium (Se) and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) have been documented. However, few studies have been conducted examining anti-tumor effects of nutritional supplements (NS) containing Se and EPA/DHA in combination with anti-cancer agents, such as taxol (Tax), adriamycin (Adr), and avastin (Ava). Compared with triple-negative breast cancer (TNBC)-bearing positive control (TB) mice, a low dose of Tax, Adr, and Ava decreased tumor size and the incidence of metastasis in TB-Tax, TB-Adr, and TB-Ava groups. Combination treatment with anti-cancer agent and NS (2.7 μg Se and 5.1 mg EPA/3.7 mg DHA/g) induced additional decreases in TB-Tax-NS, TB-Adr-NS, and TB-Ava-NS groups. Th1-associated cytokines were increased, and Th2-type cytokines were decreased significantly in TB mice with combination treatment than that of anti-cancer agent treatment alone. Combination treatment with anti-cancer agents and NS has also been shown to further increased tumor malondialdehyde (MDA) levels, lowered hypoxia-inducible factor (HIF)-1α, angiogenic markers (vascular endothelial growth factor [VEGF] and CD31) and metastatic potential, as well as reduced heat shock proteins, receptor tyrosine kinase AXL, and surface markers of cancer stem cells, and increased apoptotic proteins. For immune checkpoint molecules, combination treatment was associated with a greater decrease in programmed cell death ligand-1 (PD-L1) in both tumors and mammary glands, but PD-1 level in primary tumors was increased. Our results suggest that combination treatment with low-dose anti-cancer agents (Tax, Adr, and Ava) and oral supplementation of Se/ EPA/DHA significantly decreased tumor growth and metastatic progression in TNBC mice through multiple anti-tumor mechanisms.

Selenium-Directed ortho-C-H Borylation by Iridium Catalysis

An iridium-catalyzed selenium-directed ortho-C-H borylation of benzyl selenide derivatives was successfully developed. This is the first example where selenium is used as a directing group in C-H borylation. The reaction was carried out using the tricyclohexylphosphine ligand for an improved catalytic efficiency. Various substrates were tolerated and afforded either ortho-monoborylated products (substrates bearing ortho- or meta-substituents) or diborylated products (substrates bearing para-substituents) in good yields. This study provides an efficient synthetic method for the preparation of a variety of organoselenium compounds.

Selenium in plant foods: speciation analysis, bioavailability, and factors affecting composition

Interest in selenium has been increasing over the past few decades with growing knowledge of its importance to overall health. The ability of several plants to accumulate and transform inorganic selenium forms into its bioactive organic compounds has important implications for human nutrition and health. In this review, we present the studies carried out during the last decade to characterize selenium species produced by different plant foods. Attention is also paid to the effect of selenium treatment on chemical composition and antioxidant properties of plants.

Selenium involvement in mitochondrial function in thyroid disorders

Selenium (Se), an important oligoelement, is a component of the antioxidant system. Over the last decade, it has been ever more frequently discussed in the context of thyroid disorders. Graves' disease and Hashimoto's thyroiditis, differentiated thyroid cancer, and even endemic goiter may have common triggers that are activated by excess reactive oxygen species (ROS), which are involved in various stages of the pathogenesis of thyroid disorders. Most oxidative events occur in mitochondria, organelles that contain enzymes with Se as a cofactor. Mitochondria are responsible for the production of ATP in the cell and are also a major site of ROS production. Thyroid hormone status (the thyroid being the organ with the highest concentration of Se in the body) has a profound impact on mitochondria biogenesis. In this review, we focus on the role of Se in mitochondrial function in thyroid disorders with impaired oxidative stress, since both thyroid hormone synthesis and thyroid dysfunction involve ROS. The role of Se deficiency or its excess in relation to mitochondrial dysfunction in the context of thyroid disorders is therefore of interest.

Accumulation of Selenium in Candida utilis Growing in Media of Increasing Concentration of this Element

Selenium is considered an essential component of all living organisms. Studies on the enrichment of yeast cells with selenium, using the ability of cell biomass to bind this element, are being reported more and more. Yeast cultures were cultivated in YPD medium enriched with Na2SeO3 salts for 72 h at 28 °C on a shaker utilizing reciprocating motion. Selenium in cell biomass was determined with the use of ICP–MS. It was observed that the addition of selenium to the experimental medium (in the range of 4–100 mg/L) increased the content of this element in the yeast cell biomass. During the extension of cultivation time, the number of yeast cells and biomass yield exhibited a decreasing trend. Based on the obtained results, it was concluded that yeast cells exhibited the ability to accumulate selenium in both logarithmic and stationary growth phases. The dose of 20 and 30 mg/L of selenium in the culture medium meets the expectations in terms of both the content of selenium bound to yeast cells (1944 ± 110.8 μg/g dry weight) under 48-h cultivation. The obtained results confirmed that the Candida utilis ATCC 9950 strain exhibits the ability to bind selenium, which means that the biomass of these yeasts may be used as a natural source of selenium in the diet of humans and animals.

Novel N,N'-Disubstituted Acylselenoureas as Potential Antioxidant and Cytotoxic Agents

Selenium compounds are pivotal in medicinal chemistry for their antitumoral and antioxidant properties. Forty seven acylselenoureas have been designed and synthesized following a fragment-based approach. Different scaffolds, including carbo- and hetero-cycles, along with mono- and bi-cyclic moieties, have been linked to the selenium containing skeleton. The dose- and time-dependent radical scavenging activity for all of the compounds were assessed using the in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assays. Some of them showed a greater radical scavenging capacity at low doses and shorter times than ascorbic acid. Therefore, four compounds were evaluated to test their protective effects against H₂O₂-induced oxidative stress. One derivative protected cells against H₂O₂-induced damage, increasing cell survival by up to 3.6-fold. Additionally, in vitro cytotoxic activity of all compounds was screened against several cancer cells. Eight compounds were selected to determine their half maximal inhibitory concentration (IC₅₀) values towards breast and lung cancer cells, along with their selectivity indexes. The breast cancer cells turned out to be much more sensitive than the lung. Two compounds (5d and 10a) stood out with IC₅₀ values between 4.2 μM and 8.0 μM towards MCF-7 and T47D cells, with selectivity indexes greater than 22.9. In addition, compound 10b exhibited dual antioxidant and cytotoxic activities. Although further evidence is needed, the acylselenourea scaffold could be a feasible frame to develop new dual agents.

Increasing selenium supplementation to a moderately-reduced energy and protein diet improves antioxidant status and meat quality without affecting growth performance in finishing pigs

BACKGROUND

Along with economic development and living standards' improvement, more and more attention has been converted from satisfying meat quantity to pursuing meat quality.

RESEARCH PURPOSE

This study was conducted to evaluate the effects of increasing selenium (Se) supplementation to a moderately-reduced energy and protein diet (MREP) on growth performance, antioxidant status, meat quality in finishing pigs.

BASIC PROCEDURES

A total of 144 "Duroc × Landrace × Yorkshire" pigs with the average body weight of 75 ± 1 kg were randomly allotted to 3 dietary treatments with six replicates per treatment and eight pigs per replicate. The 3 experimental diets were as follows: (1) Normal energy and protein (NEP) +0.2 mg/kg Se diet (14.02 MJ/kg DE, 14% CP and 0.2 mg/kg Se as selenite sodium), (2) MREP +0.2 mg/kg Se diet (13.60 MJ/kg DE, 13% CP and 0.2 mg/kg Se as selenite sodium), and (3) MREP +0.5 mg/kg Se diet (13.60 MJ/kg DE, 13% CP, 0.2 mg/kg Se as selenite sodium, and 0.3 mg/kg Se as Se-enriched yeast). The study lasted for 45 days.

MAIN FINDINGS

The results show that there were no differences for growth performance, antioxidant status and meat quality of finishing pigs between NEP +0.2 mg/kg Se group and MREP +0.2 mg/kg Se group (P＞0.05). However, compared to pigs from MREP +0.2 mg/kg Se group, pigs from MREP +0.5 mg/kg Se group had greater Se concentration, GSH-Px activity and GSH concentration, but lower MDA concentration in serum (P＜0.05). Also, pigs from MREP +0.5 mg/kg Se group had greater Se concentration, T-AOC, and SOD activity, but lower MDA concentration in loin compared with pigs from MREP +0.2 mg/kg Se group (P＜0.05). As for meat quality, pigs from MREP +0.5 mg/kg Se group had greater a* value (relative redness) at 45 min and 24 h in loin compared with pigs from MREP +0.2 mg/kg Se group (P＜0.05). Compared to pigs from MREP +0.2 mg/kg Se group, pigs from MREP +0.5 mg/kg Se group had lower MDA concentration of fresh pork during a simulated retail display at 0, 1, 2, 4, 6 and 7 day (P＜0.05).

PRINCIPAL CONCLUSIONS

In conclusion, increasing selenium supplementation to a moderately-reduced energy and protein diet improved antioxidant status and meat quality without affecting growth performance in finishing pigs. (New Aspects) The present study provided a nutritional strategy for reducing feed costs and improving pork quality without influencing growth performance in finishing pigs.

Design of Rhenium Compounds in Targeted Anticancer Therapeutics

Background:

Many rhenium (Re) complexes with potential anticancer properties have been synthesized in the recent years with the aim to overcome the clinical limitations of platinum agents. Re(I) tricarbonyl complexes are the most common but Re compounds with higher oxidation states have also been investigated, as well as hetero-metallic complexes and Re-loaded self-assembling devices. Many of these compounds display promising cytotoxic and phototoxic properties against malignant cells but all Re compounds are still at the stage of preclinical studies.

Methods:

The present review focused on the rhenium based cancer drugs that were in preclinical and clinical trials were examined critically. The detailed targeted interactions and experimental evidences of Re compounds reported by the patentable and non-patentable research findings used to write this review.

Results:

In the present review, we described the most recent and promising rhenium compounds focusing on their potential mechanism of action including, phototoxicity, DNA binding, mitochondrial effects, oxidative stress regulation or enzyme inhibition. Many ligands have been described that modulating the lipophilicity, the luminescent properties, the cellular uptake, the biodistribution, and the cytotoxicity, the pharmacological and toxicological profile.

Conclusion:

Re-based anticancer drugs can also be used in targeted therapies by coupling to a variety of biologically relevant targeting molecules. On the other hand, combination with conventional cytotoxic molecules, such as doxorubicin, allowed to take into profit the targeting properties of Re for example toward mitochondria. Through the example of the diseleno-Re complex, we showed that the main target could be the oxidative status, with a down-stream regulation of signaling pathways, and further on selective cell death of cancer cells versus normal cells.

Targeting Glutathione and Cystathionine β-Synthase in Ovarian Cancer Treatment by Selenium-Chrysin Polyurea Dendrimer Nanoformulation

Ovarian cancer is the main cause of death from gynecological cancer, with its poor prognosis mainly related to late diagnosis and chemoresistance (acquired or intrinsic) to conventional alkylating and reactive oxygen species (ROS)-generating drugs. We and others reported that the availability of cysteine and glutathione (GSH) impacts the mechanisms of resistance to carboplatin in ovarian cancer. Different players in cysteine metabolism can be crucial in chemoresistance, such as the cystine/glutamate antiporter system Xc (xCT) and the H2S-synthesizing enzyme cystathionine β-synthase (CBS) in the pathway of cysteine catabolism. We hypothesized that, by disrupting cysteine metabolic flux, chemoresistance would be reverted. Since the xCT transporter is also able to take up selenium, we used selenium-containing chrysin (SeChry) as a plausible competitive inhibitor of xCT. For that, we tested the effects of SeChry on three different ovarian cancer cell lines (ES2, OVCAR3, and OVCAR8) and in two non-malignant cell lines (HaCaT and HK2). Results showed that, in addition to being highly cytotoxic, SeChry does not affect the uptake of cysteine, although it increases GSH depletion, indicating that SeChry might induce oxidative stress. However, enzymatic assays revealed an inhibitory effect of SeChry toward CBS, thus preventing production of the antioxidant H2S. Notably, our data showed that SeChry and folate-targeted polyurea dendrimer generation four (SeChry@PUREG4-FA) nanoparticles increased the specificity for SeChry delivery to ovarian cancer cells, reducing significantly the toxicity against non-malignant cells. Collectively, our data support SeChry@PUREG4-FA nanoparticles as a targeted strategy to improve ovarian cancer treatment, where GSH depletion and CBS inhibition underlie SeChry cytotoxicity.