Inverse correlation between KAI1 mRNA levels and invasive behaviour in bladder cancer cell lines.

We have previously shown that levels of KAI1 mRNA are dramatically reduced in invasive human bladder cancers. To further investigate the role of KAI1 in bladder cancer, we have examined the relationship between KAI1 mRNA levels and cell behaviour in 18 bladder cancer cell lines and a virus-transformed uro-epithelial cell line. We found that low KAI1 mRNA levels correlated with increased in vitro invasive ability, reduced Ca(2+)-dependent and -independent cell-cell adhesion and reduced adhesion to fibronectin. These data support the idea that loss of KAI1 expression is an important factor in tumour cell invasive behaviour.