The cadherin cell-cell adhesion pathway in prostate cancer progression.

Cadherins are a family of calcium-dependent cell-cell adhesion molecules involved in cell-cell aggregation and morphoregulatory cell function. Dysfunction of the cadherin pathway is involved in tumour invasiveness and disease progression for a variety of carcinomas. E-cadherin is a prognostic marker in prostatic cancer, based on the correlation of the grade of E-cadherin expression and tumour grade, stage, metastasis and survival, as well as recurrence after radical prostatectomy. P-cadherin was shown to be lost in all prostatic cancers, although this most likely reflects loss of the basal cell population rather than a transcriptional down-regulation, suggesting that loss of P-cadherin expression is an early event in the tumorigenesis of prostatic carcinomas. Catenins, particularly alpha-catenin, also play an important role in the dysfunction of the cell adhesion complex. Mechanisms of inactivation of the cadherin-catenin pathway include LOH, gene deletions and gene promoter hypermethylation. Therapeutic strategies have been investigated in tumour models, i.e. the use of demethylating agents for the hypermethylated promoter region of E-cadherin or gene transfer in PC-3 cells with homozygous deletion of the alpha-catenin gene. The complexity of neoplastic changes cannot be explained by alterations of cell adhesion molecules alone; but as demonstrated, cadherins and catenins play an important role in this process.