Inhibition of NF‐\kappaB transcriptional activity by \alpha ‐tocopheryl succinate

Article type: Research Article

Authors: Nakamura, Tetsuya^; | Goto, Masaki | Matsumoto, Akira | Tanaka, Isao

Affiliations: Department of Post Marketing Research and Drug Information, Eisai Co., Ltd., 5‐5‐5 Koishikawa, Bunkyo‐ku, Tokyo 112, Japan | Tsukuba Research Laboratories, Eisai Co., Ltd., 5‐5‐5 Koishikawa, Bunkyo‐ku, Tokyo 112, Japan | Department of Applied Drug Research, Eisai Co., Ltd., 5‐5‐5 Koishikawa, Bunkyo‐ku, Tokyo 112, Japan

Note: [] To whom correspondence should be addressed: Tetsuya Nakamura, Department of Post Marketing Research and Drug Information, Eisai Co., Ltd., 5‐5‐5 Koishikawa, Bunkyo‐ku, Tokyo 112, Japan.

Abstract: The role of vitamin E in cell regulation in addition to its function as an antioxidant has attracted attention. The effects of \alpha‐tocopherol (T) and \alpha‐tocopheryl succinate (TS) on transcriptional activation of the tumor necrosis factor alpha (TNF‐\alpha ) gene and nuclear factor kappa B (NF‐\kappa B) activation were examined. Two stable transformants were used: TR‐1 cells derived from THP‐1 cells transfected with a vector contains the human TNF‐\alpha promoter (1.4‐kb) joined to the human placental alkaline phosphatase (PLAP) coding sequence, and B164 cells derived from the same cell line but carrying the vector containing the human \beta ‐actin promoter (4.3‐kb) as a control. The transfectants were cultured in the presence of TS, followed by stimulation with lipopolysaccharide (LPS). After stimulation, PLAP activity secreted into the culture medium was measured. TS reduced TNF‐\alpha transcriptional activity in a concentration‐dependent manner, while no effect was observed on that of the \beta ‐actin promoter. Gel shift assay revealed that THP‐1 cells pretreated with TS and then with LPS showed inhibition of NF‐\kappa B activity by 43% at 50 \muM versus the TS‐untreated group. Since TS did not affect activator protein‐1 (AP‐1) activity under the same conditions, the inhibitory effect of TS on NF‐\kappa B activation might be specific. However, T had no effect on the results of the gel shift assay. Vitamin E transportation was analyzed by simultaneous determination of vitamin E and its derivatives using HPLC. The vitamin E recovered from culture pellets showed almost the same amounts of T and TS transferred and was recovered in unchanged form. These observations indicated that TS inhibited NF‐\kappa B activation and/or translocation to the nuclei in its unchanged form under the culture conditions used here. These results suggested that vitamin E is involved in signal transduction via an effect distinct from its antioxidant function. To explain the lack of activity with T, it remains to be clarified whether physiological incorporation of T occurred.

Keywords: NF‐[TeX:] \kappa B, LPS, TNF‐[TeX:] \alpha , THP‐1 cells, [TeX:] \alpha ‐tocopheryl succinate

Journal: Biofactors, vol. 7, no. 1-2, pp. 21-30, 1998