ANTISENSE SRC EXPRESSION INHIBITS U937 HUMAN LEUKEMIA-CELL PROLIFERATION IN CONJUNCTION WITH REDUCTION OF C-MYB EXPRESSION

To elucidate the role of pp60(c-src) in U937 human monoblastoid leukem ia cell proliferation, recombinant plasmids containing the src gene or myb gene, which could produce antisense src or antisense myb RNA afte r dexamethasone treatment, were constructed and transfected into U937 cells (U937-ASRC, U937-AMYB). pp60(c-src) synthesis in U937-ASRC was d iminished by the third day after induction of antisense src RNA and th e eel proliferation was reduced, furthermore, the amount of p75(c-myb) was significantly decreased by the third day. p75(c-myb) synthesis in U937-AMYB was diminished by the second day after induction of antisen se myb RNA and the cell growth was significantly inhibited but the amo unt of pp60(c-src) in U937-AMYB was not reduced. These results suggest that a decrease in the amount of pp60(c-src) leads to an inhibition o f p75(c-myb) expression and subsequent reduction in the U937 cell prol iferation. (C) 1994 Academic Press, Inc.