Suppression by carotenoids of microtenoids of microcystin‐induced morphological changes in mouse hepatocytes

• DOI: 10.1007/bf02536288
• Publication Date: 2006-11-29T20:20:58Z
• Authors: Rie Matsushima‐Ni...; Yoshihiro Shidoji; Shinji Nishiwaki; Tetsuya Yamada; Hisataka Moriwaki; Yasutoshi Muto
• Keywords: Microcystin-LR; Hyperphosphorylation

Abstract Microcystin‐LR is a liver tumor promoter in the okadaic acid class, group of potent inhibitors protein phosphatases 1 and 2A. Because inhibition phosphatases, microcystin‐LR induces hyperphosphorylation cellular proteins, including cytoskeletal proteins—cytokeratins 8 18—and causes morphological changes mouse hepatocytes primary culture. We studied effects carotenoids to antagonize microcystin‐LR‐induced hepatocytes. β‐Carotene (100 nM 100 μM), suppressed induced by dose‐dependent manner. Other tested exerted similar suppressive effects, although retinoids, such as all‐ trans retinol, retinoic acid, 9‐ cis were only weakly suppressive. The relative potency suppression correlated significantly with number conjugated double bonds configuration. strongly proteins without significant basal phosphorylation level. antioxidants, α‐tocopherol, did not protect cells against microcystin‐LR. Taken together, antagonistic are difficult explain their antioxidant or provitamin A activities. Suppression may be novel mechanism which inhibit promotion.