T\imor Necrosis Factor Acts as a 1\imor Promoter in BALB/3T3 Cell Transformation1
نویسندگان
چکیده
Tumor necrosis factor (TNF), a cytokine, and okadaic acid, a tumor promoter, strongly phosphorylated the same proteins, vimentin and heat shock protein 27, although their time courses were different. Human TNF-a at a concentration of 0.6 UMmarkedly stimulated transformation of BALB/3T3 cells initiated with 3-methylcholanthrene. The human TNF-a was about 1000 times more effective than the chemical tumor promoters, okadaic acid and U-O-tetradecanoylphorbol-lS-acetate. TNF induced growth of v-Ha-ra; transfected BALB/3T3 cells (Bhas 42 cells), whereas it did not induce growth of nontransfected BALB/3T3 cells. Oka daic acid induced mouse TNF-a from Bhas 42 and BALB/3T3 cells. The results suggest that a chemical tumor promoter induces the secretion of TNF-a from various cells. The TNF then acts as an endogenous tumor promoter in vivo.
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