Using PCR, 20 bladder tumours at differing stage and grade, a non-tumourigenic urothelial cell line (SV-HUC-1) and 17 bladder cancer cell lines were examined for expression of this alternatively spliced (AS) KAI1 mRNA.
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 have used bisulphite methylation analysis of DNA from paraffin-embedded invasive bladder tumour samples and from bladder cancer cell lines to determine if hypermethylation of a CpG island within the KAI1 promoter is responsible for this effect.
KAI1 expression is decreased in the progression of common solid epithelial tumors of adulthood, including lung, prostate, breast, esophageal, gastric, pancreatic, and bladder cancers.
Our results suggest that down-regulation of KAI1 mRNA is significantly associated with invasive bladder cancer and that KAI1 may represent an invasion/metastasis suppressor gene in bladder cancer.