Inhibition of lymphoma cell proliferation by supernatant from fibrosarcoma cultures: preliminary evidence that the inhibitory material is prostaglandin E.

Supernatants obtained from mouse fibrosarcoma cultures 48 hr after the addition of fresh medium contained dialyzable material which inhibited the proliferation of syngeneic lymphoma cells in vitro, as measured by 3H-thymidine incorporation. Three lines of evidence indicate that the supernatant inhibitory material is probably prostaglandin (PG) E. First, the supernatant and dialysis of the supernatant contained a substance with the same characteristics as PGE1 or PGE2 as detected by thin layer chromatography. Second, PGE2-treatment of lymphoma cells mimicked the inhibition of proliferation observed with supernatant inhibitory substance. Third, indomethacin, treatment of fibrosarcoma cultures reduced the amount of supernatant inhibitory substance present.