A protein produced by a monocytic human cell line can induce apoptosis on tumor cells.
A serum-free medium conditioned by U937, a human cell line of monocyte/macrophage origin, was found capable of inducing apoptosis on exponentially growing U937 cells themselves (autocrine suicide). The apoptosis-inducing agent is a macromolecule and possibly a protein (SKT factor), with a relative molecular mass in the range of 18-25 kDa. All human tumor cell lines examined have been induced to apoptosis with high efficiency, whereas non transformed human lymphocytes and monocytes are insensitive to the apoptosis-inducing activity; moreover, partially differentiated U937 are not killed but induced to full maturation. These observations suggest that the SKT factor could possibly be a cytokine with a specific cytotoxic tropism, that resembles in many respects the cytokine tumor necrosis factor (TNF), even though no TNF is detectable in the conditioned medium.
Ghibelli
L
L
Dipartimento di Biologia, Università di Roma Tor Vergata, Italy.
Coppola
S
S
Nosseri
C
C
Bergamini
A
A
Beninati
S
S
D017209:Apoptosis; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002454:Cell Differentiation; D002460:Cell Line; D017077:Culture Media, Conditioned; D016207:Cytokines / Q000096:biosynthesis / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D006801:Humans; D008264:Macrophages / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism*; D009369:Neoplasms / Q000473:pathology*; D014176:Protein Biosynthesis; D011506:Proteins / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D002087:Butyrates; D017077:Culture Media, Conditioned; D016207:Cytokines; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; D020148:Butyric Acid; D013755:Tetradecanoylphorbol Acetate; D004121:Dimethyl Sulfoxide