Background: Introduction of human chromosome 8 to a highly metastatic subline (AT6.2) from the Dunning R-3327 rat prostate cancer resulted in suppression of metastatic ability of the resultant microcell hybrids (AT6.2-8 clones) [12]. The present study has been performed to clarify which step of metastasis was suppressed in the microcell hybrids.
Methods: Northern blot analysis of E-cadherin and alpha-catenin, in vitro invasion assay, and intra-venous metastasis assay by injection of tumor cells into the lateral tail vein of nude mice were performed.
Results: No detectable expressions of either E-cadherin or alpha-catenin were found in either AT6.2 parental or AT6.2-8 microcell hybrid clones. In the invasion assay, invasiveness of AT6.2-8 hybrid clones was less than that of the AT6.2 parental clone. In the intravenous metastasis assay, no significant differences in the number of lung metastases were observed among these cell lines.
Conclusions: Introduction of human chromosome 8 to AT6.2 cells shows suppression of invasiveness and no suppression of cell dissociation or process after entry into blood circulation. This suggests that human chromosome 8 contains suppressor gene(s) for the invasive ability of prostate cancer.