Mechanisms of suppression of X-ray-induced transformation of 10T1/2 cells by lipopolysaccharide.
X-ray induced neoplastic transformation of C3H/10T1/2 cells was suppressed equally by Lipid A and LPS. We examined the effects of several modifiers of arachidonic acid (AA) metabolism in our investigation on the suppression mechanism of LPS. Dexamethasone (DM), an inhibitor of phospholipase A2 (PLA2), abolished the effect of LPS, whereas bromophenacyl bromide (BPB), another inhibitor of PLA2 did not. AA and aspirin neither changed the transformation frequency nor blocked the effect of LPS. TPA, 12-O-tetradecanoyl-phorbol-13-acetate, slightly enhanced radiation transformation, which was diminished by LPS. We also examined the effects of these modifiers on the release of radioactivity from 3H-AA-labeled 10T1/2 cells. No definite correlation was found between the change of AA metabolism and suppression of the transformation frequency by LPS. LPS, however, enhanced dose-dependent myristoylation of the 22 and 67 kDa proteins of 10T1/2 cells.
Sakiyama
H
H
Division of Physiology and Pathology, National Institute of Radiological Sciences, Chiba-shi, Japan.
Yasukawa
M
M
Nishijima
M
M
Wada
E
E
Kanegasaki
S
S
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000528:radiation effects*; D003864:Depression, Chemical; D008050:Lipid A / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D008809:Mice, Inbred C3H; D014965:X-Rays
D008050:Lipid A; D008070:Lipopolysaccharides; D016718:Arachidonic Acid