Beta-Actin-derived Peptides Isolated from Acidic Extract of Rat Spleen Suppress Tumor Cell Growth

Twenty-two fragments of beta-actin and beta-actin-related protein were isolated from the acidic extracts of rat spleen tissue. beta-Actin fragments (75-90), (78-89), and (78-88), 0.01-1 microM, decreased live cell number of L929 murine tumor fibroblasts by 80-90%, with maximal cytotoxic effect of 30-40%. The fragments of (78-90) segment and the fragment of beta-actin-related protein (69-77) were less active (inhibitory effect up to 55%, cytotoxic-up to 25%).