Type I and I-trimer collagens as substrates for breast carcinoma cells in culture. Effect on growth rate, morphological appearance and actin organization.

Type I-trimer collagen, isolated from biopsy fragments of ductal infiltrating carcinomas, was used as a substrate for human breast carcinoma cells in long-term culture to monitor growth rate, morphological appearance and actin organization in comparison with normal type I collagen and plain plastic. After 11 days of culture, type I-trimer collagen exerts a more pronounced effect on cell proliferation, leading to a final increment of cell population of 35% versus regular type I substrate. Furthermore, type I-trimer collagen induces cell motility, as testified by morphological appearance and actin immunofluorescence test. On the basis of the in vitro results, it is postulated that in vivo the stromal areas containing trimer collagen, rather than repressing invasive growth, may provide a more suitable environment for tumor proliferation and spreading-out with respect to regular type I.