Biotinylated selenocyanates: Potent and selective cytostatic agents.

Most of the currently available cytotoxic agents for tackling cancer are devoid of selectivity, thus causing severe side-effects. This situation stimulated us to develop new antiproliferative agents with enhanced affinity towards tumour cells. We focused our attention on novel chalcogen-containing compounds (thiosemicarbazones, disulfides, selenoureas, thio- and selenocyanates), and particularly on selenium derivatives, as it has been documented that this kind of compounds might act as prodrugs releasing selenium-based reactive species on tumour cells. Particularly interesting in terms of potency and selectivity was a pharmacophore comprised by a selenocyanato-alkyl fragment connected to a p-phenylenediamine residue, where the nature of the second amino moiety (free, Boc-protected, enamine-protected) provided a wide variety of antiproliferative activities, ranging from the low micromolar to the nanomolar values. The optimized structure was in turn conjugated through a peptide linkage with biotin (vitamin B7), a cellular growth promoter, whose receptor is overexpressed in numerous cancer cells; the purpose was to develop a selective vector towards malignant cells. Such biotinylated derivative behaved as a very strong antiproliferative agent, achieving GI50 values in the low nM range for most of the tested cancer cells; moreover, it was featured with an outstanding selectivity, with GI50 > 100 µM against human fibroblasts. Mechanistic studies on the mode of inhibition of the biotinylated selenocyanate revealed (Annexin-V assay) a remarkable increase in the number of apoptotic cells compared to the control experiment; moreover, depolarization of the mitochondrial membrane was detected by flow cytometry analysis, and with fluorescent microscopy, what supports the apoptotic cell death. Prior to the apoptotic events, cytostatic effects were observed against SW1573 cells using label-free cell-living imaging; therefore, tumour cell division was prevented. Multidrug resistant cell lines exhibited a reduced sensitivity towards the biotinylated selenocyanate, probably due to its P-gp-mediated efflux. Remarkably, antiproliferative levels could be restored by co-administration with tariquidar, a P-gp inhibitor; this approach can, therefore, overcome multidrug resistance mediated by the P-gp efflux system.

A New Peracetylated Oleuropein Derivative Ameliorates Joint Inflammation and Destruction in a Murine Collagen-Induced Arthritis Model via Activation of the Nrf-2/Ho-1 Antioxidant Pathway and Suppression of MAPKs and NF-κB Activation.

: Oleuropein (OL), an olive tree secoiridoid and its peracetylated derivate (Per-OL) have exhibited several beneficial effects on LPS-stimulated macrophages and murine experimental systemic lupus erythematosus (SLE). This study was designed to evaluate dietary Per-OL in comparison with OL supplementation effects on collagen-induced arthritis (CIA) murine model. Three-weeks-old DBA-1/J male mice were fed from weaning with a standard commercial diet or experimental enriched-diets in 0.05 % (w/w) OL, 0.05% and 0.025% Per-OL. After six weeks of pre-treatment, arthritis was induced by bovine collagen type II by tail base injection (day 0) and on day 21, mice received a booster injection. Mice were sacrificed 42 days after the first immunization. Both Per-OL and OL diets significantly prevented histological damage and arthritic score development, although no statistically significant differences were observed between both compounds. Also, serum collagen oligomeric matrix protein (COMP), metalloprotease (MMP)-3 and pro-inflammatory cytokines levels were ameliorated in paws from secoiridoids fed animals. Mitogen-activated protein kinases (MAPK)s and nuclear transcription factor-kappa-B (NF-κB) activations were drastically down-regulated whereas nuclear factor E2-related factor 2 (Nrf2) and heme-oxygenase-1 (HO-1) protein expressions were up-regulated in those mice fed with OL and Per-OL diets. We conclude that both Per-OL and its parent compound, OL, supplements might provide a basis for developing a new dietary strategy for the prevention of rheumatoid arthritis.

Preventive effects of dietary hydroxytyrosol acetate, an extra virgin olive oil polyphenol in murine collagen-induced arthritis.

SCOPE: Hydroxytyrosol acetate (HTy-Ac), an extra virgin olive oil (EVOO) polyphenol, has recently been reported to exhibit antioxidant and anti-inflammatory effects on LPS-stimulated macrophagesand ulcerative colitis. This study was designed to evaluate dietary HTy-Ac supplementation effects on collagen-induced arthritis (CIA) in mice. METHODS AND RESULTS: DBA-1/J mice were fed from weaning with 0.05% HTy-Ac. After 6 weeks, arthritis was induced by type II collagen. Mice were sacrificed 42 days after first immunization. Blood was recollected and paws were histological and biochemically processed. HTy-Ac diet significantly prevent edarthritis development and decreased serum IgG1 and IgG2a, cartilage olimeric matrix protein (COMP) and metalloproteinase-3 (MMP-3) levels, as well as, pro-inflammatory cytokines levels (TNF-α, IFN-γ, IL-1ß, IL-6 and IL-17A). The activation of Janus kinase-signal transducer and activator of transcription (JAK/STAT), mitogen-activated protein kinases (MAPKs) and nuclear transcription factor-kappa B (NF-κB) pathways were drastically ameliorated whereas nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) protein expressions were significantly up-regulated in those mice fed with HTy-Ac. CONCLUSION: HTy-Ac improved the oxidative events and returned pro-inflammatory proteins expression to basal levels probably through JAK/STAT, MAPKs and NF-κB pathways. HTy-Ac supplement might provide a basis for developing a new dietary strategy for the prevention of rheumatoid arthritis.

Phenolic thio- and selenosemicarbazones as multi-target drugs.

A series of isosteric phenolic thio- and selenosemicarbazones have been obtained by condensation of naturally-occurring phenolic aldehydes and thio(seleno)semicarbazides. Title compounds were designed as potential multi-target drugs, and a series of structure-activity relationships could be established upon their in vitro assays: antioxidant activity, α-glucosidase inhibition and antiproliferative activity against six human tumor cell lines: A549 (non-small cell lung), HBL-100 (breast), HeLa (cervix), SW1573 (non-small cell lung), T-47D (breast) and WiDr (colon). For the antiradical activity, selenium atom and 2 or 3 phenolic hydroxyl groups proved to be essential motifs; remarkably, the compound with the most potent activity, with a trihydroxyphenyl scaffold (EC50 = 4.87 ± 1.57 µM) was found to be stronger than natural hydroxytyrosol, a potent antioxidant present in olive oil (EC50 = 13.80 ± 1.41 µM). Furthermore, one of the thiosemicarbazones was found to be a strong non-competitive inhibitor of α-glucosidase (Ki = 9.6 ± 1.6 µM), with an 8-fold increase in activity compared to acarbose (Ki = 77.9 ± 11.4 µM), marketed for the treatment of type-2 diabetes. Most of the synthesized compounds also exhibited relevant antiproliferative activities; in particular, seleno derivatives showed GI50 values lower than 6.0 µM for all the tested cell lines; N-naphthyl mono- and dihydroxylated derivatives behaved as more potent antiproliferative agents than 5-fluorouracil or cisplatin.

Anti-inflammatory and joint protective effects of extra-virgin olive-oil polyphenol extract in experimental arthritis.

The consumption of extra virgin olive oil (EVOO) in Mediterranean countries has shown beneficial effects. A wide range of evidence indicates that phenolic compounds present in EVOO are endowed with anti-inflammatory properties. In this work, we evaluated the effects of EVOO-polyphenol extract (PE) in a model of rheumatoid arthritis, the collagen-induced arthritis model in mice. On day 0, DBA-1/J mice were immunized with bovine type II collagen. On day 21, mice received a booster injection. PE (100 and 200 mg/kg) was orally administered once a day from days 29 to 41 to arthritic mice. We have demonstrated that PE decreases joint edema, cell migration, cartilage degradation and bone erosion. PE significantly reduced the levels of proinflammatory cytokines and prostaglandin E2 in the joint as well as the expression of cyclooxygenase-2 and microsomal prostaglandin E synthase-1. Our data indicate that PE inhibits c-Jun N-terminal kinase, p38 and signal transducer and activator of transcription-3. In addition, PE decreases nuclear factor κB translocation leading to the down-regulation of the arthritic process. These results support the interest of natural diet components in the development of therapeutic products for arthritic conditions.

Phenolic compounds and antioxidant capacity of virgin olive oil.

The characterisation of virgin olive oil from Arbequina, Carrasqueña, Corniche, Manzanilla Cacereña, Morisca, Picual, and Verdial de Badajoz varieties according to the individual phenolic compounds at different ripening stage was carried out. In all olive oil varieties studied, secoiridoid derivatives were most abundant, followed by phenolic alcohols, flavonoids and phenolic acids. The secoiridoid derivatives of hydroxytyrosol were the most important complex phenols for Picual and Carrasqueña, whereas the tyrosol derivatives were the major ones found in Manzanilla Cacereña, and Verdial de Badajoz. For secoiridoid derivatives of hydroxytyrosol and tyrosol, Arbequina was the oil variety showing the lowest concentration. Tyrosol, hydroxytyrosol, vanillic acid, p-cumaric acid, luteolin, and apigenin levels were greater in early harvested samples in almost all oils analysed. Antioxidant activity measurements (antiradical, lipid peroxide inhibition, H2O2 and NO scavenging) were also accomplished for the seven varieties in the first ripening stage.