AUTOCRINE TRANSFORMING GROWTH-FACTOR-BETA (TGF-BETA) MODULATES THE 120 KD AND 105 KD RETINOBLASTOMA (RB) PROTEIN SPECIES IN CBS COLON-CARCINOMA CELLS AS REVEALED BY AN ANTISENSE TGF-BETA-1 EXPRESSION VECTOR

Specific RE protein species modulated by autocrine TGF beta are unknow n. CBS NEO (with autocrine TGF beta) and antisense TGF beta 1 transfec ted CBS RSVAS cells were compared for mitogenesis and RE species modul ation. Significantly, high MW (120, 130 kD) were abundant relative to low MW (116, 110, 105 kD combined) RE species. CBS NEO required growth factors (GF) for maximal DNA synthesis (14-fold). 120 kD and 105 kD w ere significantly modulated in CBS NEO-GF. Nutrients (N) were an suffi cient to maximally stimulate CBS RSVAS (8-fold). 130 kD and 116-110 lo w MW species were moderately induced by both N (CBS RSVAS-N) and GF (C BS NEO-GF), independent of autocrine TGF beta. In conclusion, autocrin e TGF beta (CBS) has a role in modulation of 120 kD and 105 kD RE spec ies which may play a role in the inhibitory action of autocrine TGF be ta pathway.