Synthesis, characterization, and in-vitro antitumor activity of the polyethylene glycol (350 and 1000) succinate derivatives of the tocopherol and tocotrienol isomers of Vitamin E.

Abu-Fayyad A, Nazzal S.

Int J Pharm. 2017 Mar 15;519(1-2):145-156. doi: 10.1016/j.ijpharm.2017.01.020. Epub 2017 Jan 16.

Abstract

Vitamin E refers to a group of saturated tocopherol (T) isomers and the biologically more active unsaturated tocotrienol (T₃) isomers. PEGylated α-tocopherol, commercially known as Vitamin E TPGS, has been used as an emulsifier and therapeutic agent for children with vitamin E deficiency. Limited information, however, is available about the PEG conjugates of the tocotrienol isomers of vitamin E. The current work was therefore undertaken to synthesize and characterize the water soluble polyethylene glycol (PEG 350 and 1000) derivatives of T and T₃. Yield and the identity of the synthesized products were confirmed by ¹H NMR, mass spectroscopy, HPLC, and thermal analysis. The self-assembly of the PEGylated vitamin E isomers in water at critical micelle concentrations (CMC) was further confirmed by size, zeta, and Cryo-TEM image analysis. While stable at pH 7.4, PEG conjugates were found to rapidly hydrolyze at pH 1.2. Our data showed that PEGylated T₃ isomers were significantly more active as inhibitors for P-glycoprotein than PEGylated T. The in vitro cytotoxicity of the conjugates was also tested against a large panel of normal and tumorigenic cells. Of the conjugates, γ-T₃PGS 1000 and δ-T₃PGS 1000 were found to have the least toxicity against non-tumorigenic breast and pancreatic cell lines, which may be advantageous for its use as functional excipients in drug delivery. The results from the current work have demonstrated the feasibility of synthesizing PEGylated conjugates of vitamin E isomers and highlighted the potential use of these conjugates in drug delivery as functional and safer excipients especially for γ-T₃PGS 1000 and δ-T₃PGS 1000 conjugate.

Fukushima T, Yamasaki A, Harada T, Chikumi H, Watanabe M, Okazaki R, Takata M, Hasegawa Y, Kurai J, Yanai M, Yamamoto A, Sueda Y, Halayko AJ, Shimizu E.

Yonago Acta Med. 2017 Mar 9;60(1):16-23. eCollection 2017.

Abstract

Tocotrienols, members of the vitamin E family, exist in four different isoforms (α, β, γ and δ tocotrienol) that have can be protective against brain damage, as well as having anticancer effects in vivo and in vitro. We have shown that γ-tocotrienol inhibits human airway smooth muscle cell proliferation and migration induced by platelet-derived growth factor (PDGF)-BB by suppressing RhoA activation. In this study, we tested whether γ-tocotrienol modulates transforming growth factor (TGF) -β-induced induction of human airway smooth muscle (ASM) into a contractile phenotype and concomitant synthesis of extracellular matrix proteins. ASM cells were stimulated with TGF-β1 (2 ng/mL) for 48 hours and the effect of γ-tocotrienol (50 μM) on α-smooth muscle actin, fibronectin and collagen I expression was assessed using Western blotting. The signaling pathways involved in TGF-β1 stimulation were also investigated. Results show TGF-β1 increased α-smooth muscle actin, fibronectin and collagen Ⅰ abundance by 3- to 5-fold. This response was inhibited significantly by γ-tocotrienol. Furthermore, γ-tocotrienol suppressed RhoA activation, but did not affect Smad2 or Smad3 phosphorylation. These results indicate that γ-tocotrienol has potential for benefit in modulating on airway remodeling in asthma, likely via a mechanism involving the suppression of TGF-β activation of RhoA.

Nomura SJ, Robien K, Zota AR.

J Nutr. 2017 Mar 8. pii: jn243162. doi: 10.3945/jn.116.243162. [Epub ahead of print]

Abstract

Background: Leukocyte telomere length (LTL) is a biomarker of the aging process and is associated with the risk of chronic disease. Higher exposure to cadmium may be associated with shorter LTL, and adequate nutrient concentrations may be associated with longer LTL; however, the potential interaction between metals and nutrients on LTL has yet to be examined.Objectives: The objective of this study was to evaluate whether serum concentrations of vitamins and carotenoids were associated with LTL, and whether they modified the association between blood cadmium and LTL in the US NHANES (1999-2002).Methods: We evaluated cross-sectional associations between LTL and serum concentrations of vitamin A, γ-tocopherol, α-tocopherol, folate, and vitamin B-12 (1999-2002; n = 7458) and α-carotene, β-carotene, β-cryptoxanthin, lutein + zeaxanthin, and lycopene (2001-2002; n = 4018) in a nationally representative sample of US adults (≥20 y of age) with the use of multivariable linear regression. We further investigated whether vitamin and carotenoid concentrations modified associations between blood cadmium and LTL with models stratified by serum nutrient concentrations and the inclusion of an interaction term.Results: Blood cadmium was inversely associated with LTL (percentage of LTL difference per 1 μg/L = -3.74; 95% CI: -5.35, -2.10). Serum vitamin A was positively associated (percentage of LTL difference per 1 μg/L = 4.01; 95% CI: 0.26, 7.90) and γ-tocopherol was inversely associated (percentage of LTL difference per 1 μg/dL = -2.49; 95% CI: -4.21, -0.73) with LTL. Serum folate (P-trend = 0.06) and α-tocopherol (P-trend = 0.10) were marginally positively associated with LTL, whereas vitamin B-12 (P-trend = 0.78) was not associated with LTL. Serum carotenoids were generally positively associated with LTL. Serum vitamin and carotenoid concentrations did not modify blood cadmium and LTL associations (P-interaction > 0.10).Conclusions: Results from this cross-sectional study suggest that exposure to cadmium and certain nutrients may be associated with LTL in US adults, but the serum concentrations of the vitamins and carotenoids evaluated did not modify cross-sectional associations between cadmium exposure and LTL.

Rafati A, Nourzei N, Karbalay-Doust S, Noorafshan A.

Acta Histochem. 2017 Mar;119(2):172-180. doi: 10.1016/j.acthis.2017.01.004. Epub 2017 Jan 23.

Abstract

Tartrazine is a food color that may adversely affect the nervous system. Vitamin E is a neuro-protective agent. This study aimed to evaluate the effects of tartrazine and vitamin E on the performance of rats in memory and learning tests as well as the structure of medial Prefrontal Cortex (mPFC). The rats were first divided into seven groups which received the followings for a period of seven weeks: distilled water, corn oil, vitamin E (100mg/kg/day), a low dose (50mg/kg/day) and a high dose (50mg/kg/day) of tartrazine with and without vitamin E. Behavioral tests were conducted and the brain was extracted for stereological methods The high dose of tartrazine decreased the exploration time of novel objects (P<0.01). The low and high doses of tartrazine led into an increase in working and reference memory errors in acquisition and retention phases (eight-arm radial maze) compared to distilled water group (P<0.01). Additionally, the high dose of tartrazine induced a reduction in the volume of mPFC (∼13%) and its subdivision. Not only that, but the number of neurons and glial cells (∼14%) as well as the mushroom and thin spines per dendrite length declined. The length of dendrites per neuron also reduced in comparison to the distilled water group (P<0.01). Nonetheless, concomitant treatment of the rats with vitamin E plus tartrazine prevented the above-mentioned changes. An acceptable daily dose of tartrazine could induce impairment in spatial memory and dendrite structure. Moreover, a high dose of tartrazine may defect the visual memory, mPFC structure, the spatial memory and also cause dendrite changes. Vitamin E could prevent the behavioral and structural changes.

Tu L, Wang M, Zhao WY, Zhang ZZ, Tang DF, Zhang YQ, Cao H, Zhang ZG.

Mater Sci Eng C Mater Biol Appl. 2017 Mar 1;72:177-184. doi: 10.1016/j.msec.2016.10.052. Epub 2016 Oct 26.

Abstract

Gastrointestinal stromal tumors (GIST) are one of the most common forms of mesenchymal cancers of the gastrointestinal tract. Although chemotherapeutic drugs inhibited the proliferation of GIST, however, sizable proportion of people developed resistance and therefore difficult to treat. In the present study, O-carboxymethyl chitosan (OCMC)-tocopherol polymer conjugate was synthesized and formulated into stable polymeric nanoparticles. The main aim of present study was to increase the therapeutic efficacy of miR-218 in GIST. The mean size of nanoparticles was ~110nm with a spherical shape. The miR-218 NP has been shown inhibit the cell proliferation and exhibited a superior cell apoptosis. The miR-218 NP inhibited the cell invasion and promoted the apoptosis of GIST cancer cells. In the present study, we have successfully showed that KIT1 is the target gene of miR-218 as shown by the luciferase reporter assay. These findings collectively suggest the miR-218 loaded nanoparticle by virtue of effective transfection could act as a tumor suppressor miRNA in the treatment of GIST.

Shin J, Yang SJ, Lim Y.

Exp Biol Med (Maywood). 2017 Mar;242(5):505-515. doi: 10.1177/1535370216683836. Epub 2016 Dec 13.

Abstract

Delayed wound healing is one of the major diabetic complications. During wound healing process, the early inflammatory stage is important for better prognosis. One of antioxidant nutrient, gamma-tocopherol (GT) is considered to regulate inflammatory conditions. This study investigated the effect of GT supplementation on mechanism associated with inflammation, oxidative stress, and apoptosis during early cutaneous wound healing in diabetic mice. Diabetes was induced by alloxan injection in ICR mice. All mice were divided into three groups: non-diabetic control mice (CON), diabetic control mice (DMC), and diabetic mice supplemented with GT (GT). After two weeks of GT supplementation, excisional wounds were made by biopsy punches (4 mm). Diabetic mice showed increases in fasting blood glucose (FBG) level, hyper-inflammatory response, oxidative stress, and delayed wound closure rate compared to non-diabetic mice. However, GT supplementation reduced FBG level and accelerated wound closure rate by regulation of inflammatory response-related proteins such as nuclear factor kappa B, interleukin-1β, tumor necrosis factor-α, and c-reactive protein, and oxidative stress-related markers including nuclear factor (erythroid derived 2)-like 2, NAD(P)H dehydrogenase quinone1, heme oxygenase-1, manganese superoxide dismutase, catalase and glutathione peroxidase and apoptosis-related markers such as sirtuin-1, peroxisome proliferator-activated receptor gamma coactivator 1- α, and p53 in diabetic mice. Taken together, GT would be a potential therapeutic to prevent diabetes-induced delayed wound healing by regulation of inflammatory response, apoptosis, and oxidative stress. Impact statement Gamma tocopherol has shown ameliorative effect on diabetic wound healing by regulation of inflammation, oxidative stress, and apoptosis demonstrated by nuclear factor kappa B, nuclear factor (erythroid derived 2)-like 2, and sirtuin-1.

Fusi E, Giromini C, Rebucci R, Pinotti L, Caprarulo V, Cheli F, Vitari F, Domeneghini C, Baldi A.

J Anim Physiol Anim Nutr (Berl). 2017 Mar 1. doi: 10.1111/jpn.12682. [Epub ahead of print]

Abstract

Ochratoxin A (OTA) is a potent nephrotoxic fungi metabolite that affects animal and human health. At the cellular level, OTA is able to alter functions and viability by several mechanisms of action. Several strategies to counteract its toxicity have been studied. We investigated the role of α-tocopherol in counteracting OTA oxidative damage in Madin-Darby canine kidney (MDCK) cells by pre-incubating the cells for 3 hr with the antioxidant (1 nm, 10 μm) and then adding OTA (0-1.2 μg/ml) for the following 24 hr. Cell viability, lactate dehydrogenase (LDH) release, TUNEL staining and occludin and Zo1 localization by immunofluorescence were determined. Here, 1 nm α-tocopherol was shown to significantly reduce (p < .05) the cytotoxicity, LDH release and apoptotic rate induced by OTA. The presence of the antioxidant at the same concentration maintained the localization of occludin and Zo1 in the rim of the MDCK cells after the 24-hr OTA exposure. These results indicate that a low concentration of α-tocopherol could block OTA toxicity, supporting its defensive role in the cellular membrane.

Ding Y, Peng Y, Deng L, Fan J, Huang B.

J Steroid Biochem Mol Biol. 2017 Mar;167:67-77. doi: 10.1016/j.jsbmb.2016.11.009. Epub 2016 Nov 15.

Abstract

In addition to its antioxidant properties, γ-tocotrienol also has the ability to inhibit HMG-CoA reductase, which is the key enzyme in the mevalonate pathway for cholesterol biosynthesis. Statins, the competitive inhibitors of HMG-CoA reductase, display potent anticancer activity and reversal ability of multidrug resistance in a variety of tumor cells, which is believed to be due to their inhibition of HMG-CoA reductase. Here, we determined the role of the mevalonate pathway in γ-tocotrienol-mediated reversal of multidrug resistance in cancer cells. We found both γ-tocotrienol and atorvastatin effectively reversed multidrug resistance of MCF-7/Adr and markedly inhibited the intracellular levels of FPP and GGPP. Exogenous addition of mevalonate or FPP and GGPP almost completely prevented the reversal ability of atorvastatin but only partly attenuated the reversal effect of γ-tocotrienol on doxorubicin resistance. In addition, γ-tocotrienol actively inhibited the expression of P-gp and increased the accumulation of doxorubicin in cells, which led to the enhanced G2/M arrest and cell apoptosis. Taken together, γ-tocotrienol reversed the multidrug resistance of MCF-7/Adr with a mechanism distinct from that of atorvastatin. Instead of the mevalonate pathway, the inhibition of P-gp expression is a potential mechanism by which γ-tocotrienol reverses multidrug resistance in MCF-7/Adr.

Jain S, Garg T, Kushwah V, Thanki K, Agrawal AK, Dora CP.

J Drug Target. 2017 Mar 8:1-12. doi: 10.1080/1061186X.2017.1298603. [Epub ahead of print]

Abstract

The present study evaluates the prophylactic efficacy of α-tocopherol (α-TOH), resveratrol (RES), and coenzyme Q10 (CoQ10) co-loaded self-nanoemulsifying drug delivery system (α-TOH-RES-CoQ10 SNEDDS) in 7,12-Dimethylbenz[a]anthracene (DMBA) induced breast cancer model. SNEDDS formulation components were rationally selected and optimized for maximum drug loading by applying the design of experiments and further evaluated for stability in simulated gastrointestinal fluids, functional stability of antioxidants, in vitro release, Caco-2 cell uptake, oral bioavailability and prophylactic anticancer activity. The SNEDDS demonstrated excellent stability in stimulated gastrointestinal fluids. The functional activity of antioxidants was confirmed by 2,2-diphenylpicrylhydrazyl (DPPH) scavenging assay wherein significantly (p > .05) higher antioxidant activity was observed in case of SNEDDS as compared with free antioxidants. Coumarin 6 (C-6)-loaded SNEDDS formulation demonstrated remarkably higher Caco-2 cell uptake in comparison with free C-6, indicative of efficient internalization of sub-micron SNEDDS droplets by Caco-2 cells. In line with Caco-2 cell uptake observations, α-TOH-RES-CoQ10-SNEDDS showed ∼2.30- and ∼3.64-fold increase in the AUC_0-∞ values of RES and CoQ10 in comparison with free antioxidants. Significantly lower (p < .001) tumor volume (∼327 mm³) was found in case of animals treated with α-TOH-RES-CoQ10-SNEDDS in comparison with free antioxidant combination (∼1070 mm³) and DMBA control (∼1540 mm³) groups. Conclusively, the proposed strategy posed great potential in improving the prophylactic activity of antioxidants and hold promise for further exploration.

Shiozawa N, Sugahara R, Namiki K, Sato C, Ando A, Sato A, Virgona N, Yano T.

Anticancer Drugs. 2017 Mar;28(3):289-297. doi: 10.1097/CAD.0000000000000460.

Abstract

Prostate cancer (PCa) is one of the most common cancers in Western countries and acquires a malignant phenotype, androgen-independent growth. PCa under hypoxia often has resistance to chemotherapy and radiotherapy. However, an effective therapy against PCa under hypoxia has not yet been established. In this report, we investigated the inhibitory effect of a redox-silent analogue of tocotrienol on the survival of a human androgen-independent PCa cell line (PC3) under hypoxia. We found that the redox-silent analogue exerted a cytotoxic effect on PC3 cells in a dose-dependent manner irrespective of either hypoxia or normoxia. Moreover, under hypoxia, the analogue dose dependently reduced the protein levels of hypoxia-inducible factor (HIF)-1α and HIF-2α. In addition, a specific inhibitor toward HIF-1α induced cytotoxicity on PC3 cells, whereas selective inhibition of HIF-2α exerted no effect. Furthermore, suppression of HIFs levels by the analogue in hypoxic PC3 cells was closely associated with the inactivation of Fyn, a member of the nonreceptor tyrosine kinase family, as confirmed by the action of a specific inhibitor toward the kinase (PP2). Taken together, these results suggest that the tocotrienol analogue could inhibit the survival of PC3 cells under hypoxia, mainly by the inhibition of Fyn/HIF-1α signaling, and this may lead to the establishment of a new effective therapy for androgen-independent PCa.