PRETREATMENT BY TUBULIN AGENTS DECREASES C-MYC INDUCTION IN HUMAN COLON-CARCINOMA CELL-LINE HT29-D4

For HT29-D4 cell line, we confirmed the interaction between c-Myc prot ein and microtubules by immunoprecipitation, We then studied the effec t of antimitotic agents, nocodazole and the taxoids [paclitaxel (taxol ) and docetaxel (taxotere)] on c-myc oncogene expression, The expressi on was analysed by RT-PCR and Western blot, Taxol (1 mu M), taxotere ( 1 mu M) and nocodazole (3 mu M) inhibited by 30-50% the c-myc inductio n produced by growth factors in culture medium, According to the flow cytometry analysis, the inhibition is not linked to the mitotic block, These results observed for both stabilizing and depolymerizing agents suggest that microtubular system is involved in c-myc expression more through its dynamic properties which influence signal transduction an d intracellular transports than through its direct interaction with c- Myc protein. (C) 1997 Academic Press.