Flavone acetic acid suppresses human peripheral blood lymphocyte and human colonic lamina propria lymphocyte DNA synthesis.

Flavone 8-acetic acid (FAA) is a new experimental antitumor drug with activity against various murine and human solid tumors in vitro and in vivo. We previously demonstrated that FAA suppressed the growth of a human colon cancer cell line (HCT-116). In this study we investigated the effect of FAA on human peripheral blood (PBL) and human colonic lamina propria lymphocyte (LPL) DNA synthesis. Our results show that FAA inhibited DNA synthesis in PBL and LPL in a dose-dependent fashion. In addition, FAA inhibited the activity of the intracellular enzyme, ornithine decarboxylase (ODC), in stimulated PBL and LPL. FAA did not inhibit phorbol ester (PDB) and calcium ionophor(ionomycin)-stimulated LPL DNA synthesis. These results suggest that FAA alters DNA synthesis of human peripheral and colonic mucosal lymphocytes. We postulate that FAA may affect the human peripheral and mucosal immune system.