Production and significance of TGF-beta in AT-3 metastatic cell line established from the Dunning rat prostatic adenocarcinoma

Abstract

A colony formation assay using NRK-49F cells revealed that a metastatic cell line, AT-3, established from the Dunning prostatic carcinoma could produce TGF-beta in a latent form. TGF-beta at a concentration as low as 0.05 ng/ml either stimulated the attachment or detachment of AT-3 cells depending on the kind of culture media. Acid extracts from conditioned medium (5 micrograms/ml) showed the activity comparable to that of TGF-beta (5 ng/ml). The detached cells were able to grow in suspension. TGF-beta (0.1 ng/ml) could also stimulate the growth of MC3T3-El osteoblasts established from mouse calvaria. These results suggest that TGF-beta is a key growth factor for osteoblastic bony metastasis of prostate cancer.