A novel human tocopherol-associated protein: cloning, in vitro expression, and characterization.

Vitamin E (alpha-tocopherol) is an essential dietary nutrient for humans and animals. The mechanisms involved in cellular regulation as well as in the preferential cellular and tissue accumulation of alpha-tocopherol are not yet well established. We previously reported (Stocker, A., Zimmer, S., Spycher, S. E., and Azzi, A. (1999) IUBMB Life 48, 49-55) the identification of a novel 46-kDa tocopherol-associated protein (TAP) in the cytosol of bovine liver. Here, we describe the identification, the molecular cloning into Escherichia coli, and the in vitro expression of the human homologue of bovine TAP, hTAP. This protein appears to belong to a family of hydrophobic ligand binding proteins, which have the CRAL (cis-retinal binding motif) sequence in common. By using a biotinylated alpha-tocopherol derivative and the IASys resonant mirror biosensor, the purified recombinant protein was shown to bind tocopherol at a specific binding site with K(d) 4.6 x 10(-7) m. Northern analyses showed that hTAP mRNA has a size of approximately 2800 base pairs and is ubiquitously expressed. The highest amounts of hTAP message are found in liver, brain, and prostate. In conclusion, hTAP has sequence homology to proteins containing the CRAL_TRIO structural motif. TAP binds to alpha-tocopherol and biotinylated tocopherol, suggesting the existence of a hydrophobic pocket, possibly analogous to that of SEC14

Protective effect of dendrosomal curcumin combination on colon cancer in rat

Background: Cancer is a multistep process that develops very rapidly after its onset. Previous studies have confirmed antitumor effects of curcumin (1,7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione diferuloylmethane) that can potentially prevent colon cancer development with low side-effects. Different methods have been performed to increase the efficiency and effectiveness of curcumin among which dendrosome, a nanoparticle created by Sarbolouki et al. was used in this study. The present study was undertaken to evaluate the effects of dendrosomal curcumin on rat colon cancer. Methods: In this study which was performed in Cancer Research Center of Tehran University of Medical Sciences in 2010 year, forty rats were equally divided into control, curcumin and curcumin-dendrosome groups. Animals received azoxymethane (15 mg/kg s.c.), a carcinogen, once a week for two weeks. Curcumin (0.2%) and curcumin-dendrosome were administered to the respective animals 2 weeks before the first and 14 weeks after the last azoxymethane injections. Eventually, colorectal specimens from tumoral and adjacent non-tumoral mucosal tissues were fixed in 10% formaldehyde, and passaged and embedded in paraffin. Histopathological and immunohistochemical studies were performed on the specimens. Results: The mean number of lesions, nuclear/cytoplasmic ratio, epithelial stratification, loss of nuclear polarity, goblet depletion, structural abnormality and beta-catenin expression were higher in the control group compared to curcumin and curcumin-dendrosome groups. These parameters had significantly decreased in the dendrosomal curcumin group (P<0.05). Conclusion: The present study shows that dendrosome can be used as a suitable nanoparticle to increase curcumin efficiency in the prevention or treatment of colon cancer

Effects of EPA and vitamin E on serum enzymatic antioxidants and peroxidation indices in patients with type II diabetes mellitus

Background: Diabetes mellitus is associated with chronic changes in peripheral arteries because of oxidative stress and insufficient antioxidative defense mechanism. Omega-3 fatty acid supplementation could be effective in some diabetes complications; however, polyunsaturated fatty acids may increase lipid peroxidation. This study aimed to determine whether eicosapentaenoic acid alone or in conjunction with vitamin E had differential effects on serum antioxidants and peroxidation indices. Methods: This double-blind, placebo-controlled trial was carried out on 136 patients with type II diabetic mellitus (age 48.8±4.4 yr, BMI 27.8±1.7 kg/m2). The four groups of the study either received two grams of omega-3 fatty acids, 400 IU of vitamin E, a combination of the two or placebo for three months. Their serum total antioxidant capacity, enzymatic antioxidants and peroxidation indices were assessed. Result: Fasting serum TAC increased in EPA+E (10.7, P&lt; 0.001) and E groups (7.5, P&lt; 0.05). SOD, G-PX and G-RD increased in EPA group (7.3, 5.1, and 8.4, P&lt; 0.05, respectively). MDA and protein carbonyl decreased in EPA and E groups (respectively, 12.5, 7.6 P&lt; 0.05, P&lt; 0.05; 13, 15.3 P&lt; 0.001, P&lt; 0.05). After adjustment for baseline values, age, sex, BMI and duration of diagnosed diabetes, protein carbonyl decreased in EPA+E and E group (30.7, 15.3; P&lt; 0.05 respectively) relative to the placebo group. Conclusion: EPA, by itself has a statistically significant effect on serum total antioxidant capacity, enzymatic antioxidants and peroxidation indices in diabetic patients compared to EPA+E or E alone