Iwamoto S, Takeda K, Kamijo R, Konno K
1st Department of Biochemistry, School of Medicine, Showa University, Tokyo, Japan.
Biochem Biophys Res Commun. 1990 Jul 16;170(1):73-9. doi: 10.1016/0006-291x(90)91242-k.
1,25-dihydroxyvitamin D3 (1,25(OH)2D3) dose-dependently inhibited the cytotoxicity of tumor necrosis factor (TNF) in a human monoblastic leukemic cell line, U-937. Combination of TNF and 1,25(OH)2D3 remarkably increased mitochondrial superoxide dismutase (mSOD) of U-937 cells, TNF alone increased it only slightly and 1,25(OH)2D3 alone did not. The cytosolic SOD (cSOD) activity was not changed by TNF or/and 1,25(OH)2D3. The mSOD activity was not inhibited by 2 mM KCN, suggesting that mSOD should be a manganese SOD (MnSOD). These results suggest that 1,25(OH)2D3 may reduce the susceptibility to TNF cytotoxicity of U-937 cells by enhancing the ability of inducing MnSOD by TNF.
1,25 - 二羟维生素D3（1,25(OH)2D3）呈剂量依赖性地抑制肿瘤坏死因子（TNF）对人单核细胞白血病细胞系U - 937的细胞毒性。TNF与1,25(OH)2D3联合使用显著增加了U - 937细胞的线粒体超氧化物歧化酶（mSOD），单独使用TNF仅使其略有增加，而单独使用1,25(OH)2D3则无此作用。细胞溶质超氧化物歧化酶（cSOD）活性不受TNF或/和1,25(OH)2D3的影响。2 mM的KCN不抑制mSOD活性，提示mSOD应为锰超氧化物歧化酶（MnSOD）。这些结果表明，1,25(OH)2D3可能通过增强TNF诱导MnSOD的能力来降低U - 937细胞对TNF细胞毒性的敏感性。
