title: Alpha lipoic acid selectively inhibits proliferation and adhesion to fibronectin of v-H-ras-transformed 3Y1 cells.
abstract: Here, we focused on the effects of racemic α-lipoic acid on proliferation and adhesion properties of 3Y1 rat fibroblasts and the v-H-ras-transformed derivative, HR-3Y1-2 cells. Racemic α-lipoic acid inhibited proliferation of HR-3Y1-2 but not 3Y1 cells at 0.3 and 1.0 mM. R-(+)-α-lipoic acid also inhibited proliferation of HR-3Y1-2 cells equivalent to that of racemic α-lipoic acid. In addition, racemic α-lipoic acid decreased intracellular reactive oxygen species levels in HR-3Y1 cells but not 3Y1 cells. Next, we evaluated the effects of racemic α-lipoic acid on cell adhesion to fibronectin. The results indicated that racemic α-lipoic acid decreased adhesive ability of HR-3Y1-2 cells to fibronectin-coated plates. As blocking antibody experiment revealed that β1-integrin plays a key role in cell adhesion in this experimental system, the effects of racemic α-lipoic acid on the expression of β1-integrin were examined. The results indicated that racemic α-lipoic acid selectively downregulated the expression of cell surface β1-integrin expression in HR-3Y1-2 cells. Intriguingly, exogenous hydrogen peroxide upregulated cell surface β1-integrin expression in 3Y1 cells. Taken together, these data suggest that reduction of intracellular reactive oxygen species levels by α-lipoic acid could be an effective means of ameliorating abnormal growth and adhesive properties in v-H-ras transformed cells.
authors.affiliation: Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuenkibanadai-nishi, Miyazaki 889-2192, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Yamasaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iwase
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kawano
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sakakibara
authors.forename: Masahito
authors.initials: M
authors.lastname: Suiko
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nishiyama