A comparative evaluation of various invasion assays testing colon carcinoma cell lines

Various colon carcinoma cell lines were tested in different invasion assays , i.e. invasion into Matrigel, into confluent fibroblast layers and into ch icken heart tissue. Furthermore, invasive capacity and metastatic potential were determined in nude mice. The colon carcinoma cells used were the huma n cell lines Caco-2, SW-480, SW-620 and HT-29, and the murine lines Colon-2 6 and -38. None of the human colon carcinoma cells migrated through porous membranes coated with Matrigel; of the murine lines, only Colon-26 did. Whe n incubated in a mixture of Matrigel and culture medium non-invading cells formed spheroid cultures, whereas invading cells showed a stellate outgrowt h. Only the heterogeneously shaped (epithelioid and stellate) cells of SW-4 80 and SW-620 and the spindle-shaped cells of Colon-26 invaded clearly conf luent skin and colon fibroblasts as well as chicken heart tissue. However, when transplanted into the caecum of nude and syngeneic mice, all the lines tested were invasive with the exception of Caco-2 cells. We conclude that the outcome of in vitro tests measuring the invasive capacity of neoplastic cells is largely dependent on the test system used. invasive capacity in v itro is strongly correlated with cells having a spindle cell shape, vimenti n expression and E-cadherin down regulation. In contrast, HT-29 and Colon-3 8 cells having an epithelioid phenotype were clearly invasive and metastati c in vivo, but not in vitro. (C) 1999 Cancer Research Campaign.