Redox regulation of the tumor suppressor PTEN by the thioredoxin system and cumene hydroperoxide.

Intracellular redox status influences the oxidation and enzyme activity of the tumor suppressor phosphatase and tensin homolog on chromosome 10 (PTEN). Cumene hydroperoxide (CuHP), an organic hydroperoxide, is a known tumor promoter. However, molecular targets and action mechanism of CuHP in tumor promotion have not been well characterized.

Redox Regulation of the Tumor Suppressor PTEN by Hydrogen Peroxide and Tert-Butyl Hydroperoxide.

Organic peroxides and hydroperoxides are skin tumor promoters. Free radical derivatives from these compounds are presumed to be the prominent mediators of tumor promotion. However, the molecular targets of these species are unknown.

Protective effect of diet supplemented with rice prolamin extract against DNCB-induced atopic dermatitis in BALB/c mice.

Background: Rice prolamin has been reported to possess antioxidative, anti-inflammatory and immune-promoting properties. This study is aimed to examine the protective effects of dietary rice prolamin extract (RPE) against dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like skin lesions in mice.

Methods: BALB/c mice were fed diet supplemented with 0-0.

Assay of the redox state of the tumor suppressor PTEN by mobility shift.

PTEN is reversibly oxidized in various cells by exogenous hydrogen peroxide as well as by endogenous hydrogen peroxide generated when cells are stimulated with growth factors, cytokines and hormones. A gel mobility shift assay showed that oxidized PTEN migrated more rapidly than reduced PTEN on a non-reducing SDS-PAGE gel. Oxidized PTEN was reduced when treated with dithiothreitol.

Use of non-melanocytic HEK293 cells stably expressing human tyrosinase for the screening of anti-melanogenic agents.

Tyrosinase (TYR) from mushrooms has been inappropriately used in the screening assay for hypopigmenting agents even though its biochemical properties are different from those of human TYR. Cell-free extracts of human epidermal melanocyes (HEMs) could be another choice for the assay, but HEMs grow too slowly to get a sufficient amount of cell-free extracts. In the present study, human embryonic kidney (HEK) 293 cells were transfected with a human TYR construct to establish a cell line that grows rapidly and expresses human TYR constitutively.