Blocking basement membrane collagen deposition inhibits the growth of 7,12-dimethylbenzanthracene-induced rat mammary tumors.

7,12-Dimethylbenzanthracene-induced rat mammary tumors contain basement membrane collagen in vivo and in vitro in primary culture, as determined by immunofluorescence. The proline analogue dis-hydroxyproline, which selectively blocks collagen accumulation, inhibits tumor cell growth in vitro. In vivo cis-hydroxyproline blocks tumor growth and produces epithelial cell degeneration and tumor necrosis at a non-toxic dose. This compound has no effect on the growth of the mammary carcinoma cell line 64/24, which makes no basement membrane collagen. As we have previously described for the normal proliferating rat mammary gland, basement membrane collagen deposition may be necessary for the growth of some rat mammary tumors.